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Sample records for ten leading vaccine-candidate

  1. Differing patterns of selection and geospatial genetic diversity within two leading Plasmodium vivax candidate vaccine antigens.

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    Christian M Parobek

    2014-04-01

    Full Text Available Although Plasmodium vivax is a leading cause of malaria around the world, only a handful of vivax antigens are being studied for vaccine development. Here, we investigated genetic signatures of selection and geospatial genetic diversity of two leading vivax vaccine antigens--Plasmodium vivax merozoite surface protein 1 (pvmsp-1 and Plasmodium vivax circumsporozoite protein (pvcsp. Using scalable next-generation sequencing, we deep-sequenced amplicons of the 42 kDa region of pvmsp-1 (n = 44 and the complete gene of pvcsp (n = 47 from Cambodian isolates. These sequences were then compared with global parasite populations obtained from GenBank. Using a combination of statistical and phylogenetic methods to assess for selection and population structure, we found strong evidence of balancing selection in the 42 kDa region of pvmsp-1, which varied significantly over the length of the gene, consistent with immune-mediated selection. In pvcsp, the highly variable central repeat region also showed patterns consistent with immune selection, which were lacking outside the repeat. The patterns of selection seen in both genes differed from their P. falciparum orthologs. In addition, we found that, similar to merozoite antigens from P. falciparum malaria, genetic diversity of pvmsp-1 sequences showed no geographic clustering, while the non-merozoite antigen, pvcsp, showed strong geographic clustering. These findings suggest that while immune selection may act on both vivax vaccine candidate antigens, the geographic distribution of genetic variability differs greatly between these two genes. The selective forces driving this diversification could lead to antigen escape and vaccine failure. Better understanding the geographic distribution of genetic variability in vaccine candidate antigens will be key to designing and implementing efficacious vaccines.

  2. Promising new vaccine candidates against Campylobacter in broilers.

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    Marine Meunier

    Full Text Available Campylobacter is the leading cause of human bacterial gastroenteritis in the European Union. Birds represent the main reservoir of the bacteria, and human campylobacteriosis mainly occurs after consuming and/or handling poultry meat. Reducing avian intestinal Campylobacter loads should impact the incidence of human diseases. At the primary production level, several measures have been identified to reach this goal, including vaccination of poultry. Despite many studies, however, no efficient vaccine is currently available. We have recently identified new vaccine candidates using the reverse vaccinology strategy. This study assessed the in vivo immune and protective potential of six newly-identified vaccine antigens. Among the candidates tested on Ross broiler chickens, four (YP_001000437.1, YP_001000562.1, YP_999817.1, and YP_999838.1 significantly reduced cecal Campylobacter loads by between 2 and 4.2 log10 CFU/g, with the concomitant development of a specific humoral immune response. In a second trial, cecal load reductions results were not statistically confirmed despite the induction of a strong immune response. These vaccine candidates need to be further investigated since they present promising features.

  3. Identification of Novel Potential Vaccine Candidates against Tuberculosis Based on Reverse Vaccinology

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    Gloria P. Monterrubio-López

    2015-01-01

    Full Text Available Tuberculosis (TB is a chronic infectious disease, considered as the second leading cause of death worldwide, caused by Mycobacterium tuberculosis. The limited efficacy of the bacillus Calmette-Guérin (BCG vaccine against pulmonary TB and the emergence of multidrug-resistant TB warrants the need for more efficacious vaccines. Reverse vaccinology uses the entire proteome of a pathogen to select the best vaccine antigens by in silico approaches. M. tuberculosis H37Rv proteome was analyzed with NERVE (New Enhanced Reverse Vaccinology Environment prediction software to identify potential vaccine targets; these 331 proteins were further analyzed with VaxiJen for the determination of their antigenicity value. Only candidates with values ≥0.5 of antigenicity and 50% of adhesin probability and without homology with human proteins or transmembrane regions were selected, resulting in 73 antigens. These proteins were grouped by families in seven groups and analyzed by amino acid sequence alignments, selecting 16 representative proteins. For each candidate, a search of the literature and protein analysis with different bioinformatics tools, as well as a simulation of the immune response, was conducted. Finally, we selected six novel vaccine candidates, EsxL, PE26, PPE65, PE_PGRS49, PBP1, and Erp, from M. tuberculosis that can be used to improve or design new TB vaccines.

  4. PROTECTIVE ACTIVITY STUDY OF A CANDIDATE VACCINE AGAINST ROTAVIRUS INFECTION BASED ON RECOMBINANT PROTEIN FliCVP6VP8

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    I. V. Dukhovlinov

    2016-01-01

    Full Text Available Rotavirus infection is among leading causes of severe diarrhea which often leads to severe dehydration, especially, in children under 5 years old. In Russia, the incidence of rotavirus infection is constantly increased, due to higher rates of actual rotavirus infection cases and improved diagnostics of the disease. Immunity to rotavirus is unstable, thus causing repeated infections intra vitam. Anti-infectious resistance in reconvalescents is explained by induction of specific IgM, IgG, and, notably, IgA antibodies. Due to absence of market drugs with direct action against rotavirus, a rational vaccination is considered the most effective way to control the disease. Currently available vaccines for prevention of rotavirus infection are based on live attenuated rotavirus strains, human and/or animal origin, which replicate in human gut. Their implementation may result into different complications. Meanwhile, usage of vaccines based on recombinant proteins is aimed to avoid risks associated with introduction of a complete virus into humans. In this paper, we studied protective activity of candidate vaccines against rotavirus.In this work we studied protective activity of a candidate vaccine against rotavirus infection based on recombinant FliCVP6VP8 protein which includes VP6 and VP8, as well as components of Salmonella typhimurium flagellin (FliC as an adjuvant. Different components are joined by flexible bridges. Efficiency of the candidate vaccine was studied in animal model using Balb/c mice. We have shown high level of protection which occurs when the candidate vaccine is administered twice intramuscularly. Complete protection of animals against mouse rotavirus EDC after intramuscular immunization with a candidate vaccine was associated with arising rotavirus-specific IgA and IgG antibodies in serum and intestine of immunized animals. The efficacy of candidate vaccine based on recombinant protein FliCVP6VP8 against rotavirus infection was

  5. Advanced Vaccine Candidates for Lassa Fever

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    Igor S. Lukashevich

    2012-10-01

    Full Text Available Lassa virus (LASV is the most prominent human pathogen of the Arenaviridae. The virus is transmitted to humans by a rodent reservoir, Mastomys natalensis, and is capable of causing lethal Lassa Fever (LF. LASV has the highest human impact of any of the viral hemorrhagic fevers (with the exception of Dengue Fever with an estimated several hundred thousand infections annually, resulting in thousands of deaths in Western Africa. The sizeable disease burden, numerous imported cases of LF in non-endemic countries, and the possibility that LASV can be used as an agent of biological warfare make a strong case for vaccine development. Presently there is no licensed vaccine against LF or approved treatment. Recently, several promising vaccine candidates have been developed which can potentially target different groups at risk. The purpose of this manuscript is to review the LASV pathogenesis and immune mechanisms involved in protection. The current status of pre-clinical development of the advanced vaccine candidates that have been tested in non-human primates will be discussed. Major scientific, manufacturing, and regulatory challenges will also be considered.

  6. Novel approaches to identify protective malaria vaccine candidates

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    Wan Ni eChia

    2014-11-01

    Full Text Available Efforts to develop vaccines against malaria have been the focus of substantial research activities for decades. Several categories of candidate vaccines are currently being developed for protection against malaria, based on antigens corresponding to the pre-erythrocytic, blood-stage or sexual stages of the parasite. Long lasting sterile protection from Plasmodium falciparum sporozoite challenge has been observed in human following vaccination with whole parasite formulations, clearly demonstrating that a protective immune response targeting predominantly the pre-erythrocytic stages can develop against malaria. However, most of vaccine candidates currently being investigated, which are mostly subunits vaccines, have not been able to induce substantial (>50% protection thus far. This is due to the fact that the antigens responsible for protection against the different parasite stages are still yet to be known and relevant correlates of protection have remained elusive. For a vaccine to be developed in a timely manner, novel approaches are required. In this article, we review the novel approaches that have been developed to identify the antigens for the development of an effective malaria vaccine.

  7. A novel live-attenuated vaccine candidate for mayaro Fever.

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    William J Weise

    2014-08-01

    Full Text Available Mayaro virus (MAYV is an emerging, mosquito-borne alphavirus that causes a dengue-like illness in many regions of South America, and which has the potential to urbanize. Because no specific treatment or vaccine is available for MAYV infection, we capitalized on an IRES-based approach to develop a live-attenuated MAYV vaccine candidate. Testing in infant, immunocompetent as well as interferon receptor-deficient mice demonstrated a high degree of attenuation, strong induction of neutralizing antibodies, and efficacy against lethal challenge. This vaccine strain was also unable to infect mosquito cells, a major safety feature for a live vaccine derived from a mosquito-borne virus. Further preclinical development of this vaccine candidate is warranted to protect against this important emerging disease.

  8. Update on the Clinical Development of Candidate Malaria Vaccines

    National Research Council Canada - National Science Library

    Ballou, W. R; Arevalo-Herrera, Myriam; Carucci, Daniel; Richie, Thomas L; Corradin, Giampietro; Diggs, Carter; Druilhe, Pierre; Giersing, Birgitte K; Saul, Allan; Heppner, D. G

    2004-01-01

    ... powerful driver for stimulating clinical development of candidate vaccines for malaria. This new way forward promises to greatly increase the likelihood of bringing a safe and effective vaccine to licensure...

  9. Efficacy of chimeric Pestivirus vaccine candidates against classical swine fever: protection and DIVA characteristics.

    Science.gov (United States)

    Eblé, P L; Geurts, Y; Quak, S; Moonen-Leusen, H W; Blome, S; Hofmann, M A; Koenen, F; Beer, M; Loeffen, W L A

    2013-03-23

    Currently no live DIVA (Differentiating Infected from Vaccinated Animals) vaccines against classical swine fever (CSF) are available. The aim of this study was to investigate whether chimeric pestivirus vaccine candidates (CP7_E2alf, Flc11 and Flc9) are able to protect pigs against clinical signs, and to reduce virus shedding and virus transmission, after a challenge with CSF virus (CSFV), 7 or 14 days after a single intramuscular vaccination. In these vaccine candidates, either the E2 or the E(rns) encoding genome region of a bovine viral diarrhoea virus strain were combined with a cDNA copy of CSFV or vice versa. Furthermore, currently available serological DIVA tests were evaluated. The vaccine candidates were compared to the C-strain. All vaccine candidates protected against clinical signs. No transmission to contact pigs was detected in the groups vaccinated with C-strain, CP7_E2alf and Flc11. Limited transmission occurred in the groups vaccinated with Flc9. All vaccine candidates would be suitable to stop on-going transmission of CSFV. For Flc11, no reliable differentiation was possible with the current E(rns)-based DIVA test. For CP7_E2alf, the distribution of the inhibition percentages was such that up to 5% false positive results may be obtained in a large vaccinated population. For Flc9 vaccinated pigs, the E2 ELISA performed very well, with an expected 0.04% false positive results in a large vaccinated population. Both CP7_E2alf and Flc9 are promising candidates to be used as live attenuated marker vaccines against CSF, with protection the best feature of CP7_E2alf, and the DIVA principle the best feature of Flc9. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Generation and Characterization of Live Attenuated Influenza A(H7N9 Candidate Vaccine Virus Based on Russian Donor of Attenuation.

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    Svetlana Shcherbik

    Full Text Available Avian influenza A (H7N9 virus has emerged recently and continues to cause severe disease with a high mortality rate in humans prompting the development of candidate vaccine viruses. Live attenuated influenza vaccines (LAIV are 6:2 reassortant viruses containing the HA and NA gene segments from wild type influenza viruses to induce protective immune responses and the six internal genes from Master Donor Viruses (MDV to provide temperature sensitive, cold-adapted and attenuated phenotypes.LAIV candidate A/Anhui/1/2013(H7N9-CDC-LV7A (abbreviated as CDC-LV7A, based on the Russian MDV, A/Leningrad/134/17/57 (H2N2, was generated by classical reassortment in eggs and retained MDV temperature-sensitive and cold-adapted phenotypes. CDC-LV7A had two amino acid substitutions N123D and N149D (H7 numbering in HA and one substitution T10I in NA. To evaluate the role of these mutations on the replication capacity of the reassortants in eggs, the recombinant viruses A(H7N9RG-LV1 and A(H7N9RG-LV2 were generated by reverse genetics. These changes did not alter virus antigenicity as ferret antiserum to CDC-LV7A vaccine candidate inhibited hemagglutination by homologous A(H7N9 virus efficiently. Safety studies in ferrets confirmed that CDC-LV7A was attenuated compared to wild-type A/Anhui/1/2013. In addition, the genetic stability of this vaccine candidate was examined in eggs and ferrets by monitoring sequence changes acquired during virus replication in the two host models. No changes in the viral genome were detected after five passages in eggs. However, after ten passages additional mutations were detected in the HA gene. The vaccine candidate was shown to be stable in the ferret model; post-vaccination sequence data analysis showed no changes in viruses collected in nasal washes present at day 5 or day 7.Our data indicate that the A/Anhui/1/2013(H7N9-CDC-LV7A reassortant virus is a safe and genetically stable candidate vaccine virus that is now available for

  11. Meta-analysis of variables affecting mouse protection efficacy of whole organism Brucella vaccines and vaccine candidates

    Science.gov (United States)

    2013-01-01

    Background Vaccine protection investigation includes three processes: vaccination, pathogen challenge, and vaccine protection efficacy assessment. Many variables can affect the results of vaccine protection. Brucella, a genus of facultative intracellular bacteria, is the etiologic agent of brucellosis in humans and multiple animal species. Extensive research has been conducted in developing effective live attenuated Brucella vaccines. We hypothesized that some variables play a more important role than others in determining vaccine protective efficacy. Using Brucella vaccines and vaccine candidates as study models, this hypothesis was tested by meta-analysis of Brucella vaccine studies reported in the literature. Results Nineteen variables related to vaccine-induced protection of mice against infection with virulent brucellae were selected based on modeling investigation of the vaccine protection processes. The variable "vaccine protection efficacy" was set as a dependent variable while the other eighteen were set as independent variables. Discrete or continuous values were collected from papers for each variable of each data set. In total, 401 experimental groups were manually annotated from 74 peer-reviewed publications containing mouse protection data for live attenuated Brucella vaccines or vaccine candidates. Our ANOVA analysis indicated that nine variables contributed significantly (P-value Brucella vaccine protection efficacy: vaccine strain, vaccination host (mouse) strain, vaccination dose, vaccination route, challenge pathogen strain, challenge route, challenge-killing interval, colony forming units (CFUs) in mouse spleen, and CFU reduction compared to control group. The other 10 variables (e.g., mouse age, vaccination-challenge interval, and challenge dose) were not found to be statistically significant (P-value > 0.05). The protection level of RB51 was sacrificed when the values of several variables (e.g., vaccination route, vaccine viability, and

  12. Comparative Infectivity Determinations of Dengue Virus Vaccine Candidates in Rhesus Monkeys, Mosquitoes, and Cell Cultures

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    1993-01-28

    34 are required for the evaluation of these vaccine candidates. RE: DAMDI7-89-C-9175 Page 16 REFERENCES 1. Sabin AB, Sclesinger RW, 1945. Production of...AD-A261 892 CONTRACT NO: DAMD17-89-C-9 175 \\II\\IllI\\I\\I1\\\\~il\\ TITLE: COMPARATIVE INFECTIVITY DETERMINATIONS OF DENGUE VIRUS VACCINE CANDIDATES IN... Vaccine Candidates in Rhesus Monkeys, 63002A Mosquitoes, and Cell Cultures 3M263002D870 AC 6. AUTHOR(S) DA335475 Edmundo Kraiselburd 7. PERFORMING

  13. Evidence for globally shared, cross-reacting polymorphic epitopes in the pregnancy-associated malaria vaccine candidate VAR2CSA

    DEFF Research Database (Denmark)

    Avril, Marion; Kulasekara, Bridget R; Gose, Severin O

    2008-01-01

    Pregnancy-associated malaria (PAM) is characterized by the placental sequestration of Plasmodium falciparum-infected erythrocytes (IEs) with the ability to bind to chondroitin sulfate A (CSA). VAR2CSA is a leading candidate for a pregnancy malaria vaccine, but its large size ( approximately 350 k...

  14. Differing Efficacies of Lead Group A Streptococcal Vaccine Candidates and Full-Length M Protein in Cutaneous and Invasive Disease Models

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    Tania Rivera-Hernandez

    2016-06-01

    Full Text Available Group A Streptococcus (GAS is an important human pathogen responsible for both superficial infections and invasive diseases. Autoimmune sequelae may occur upon repeated infection. For this reason, development of a vaccine against GAS represents a major challenge, since certain GAS components may trigger autoimmunity. We formulated three combination vaccines containing the following: (i streptolysin O (SLO, interleukin 8 (IL-8 protease (Streptococcus pyogenes cell envelope proteinase [SpyCEP], group A streptococcal C5a peptidase (SCPA, arginine deiminase (ADI, and trigger factor (TF; (ii the conserved M-protein-derived J8 peptide conjugated to ADI; and (iii group A carbohydrate lacking the N-acetylglucosamine side chain conjugated to ADI. We compared these combination vaccines to a “gold standard” for immunogenicity, full-length M1 protein. Vaccines were adjuvanted with alum, and mice were immunized on days 0, 21, and 28. On day 42, mice were challenged via cutaneous or subcutaneous routes. High-titer antigen-specific antibody responses with bactericidal activity were detected in mouse serum samples for all vaccine candidates. In comparison with sham-immunized mice, all vaccines afforded protection against cutaneous challenge. However, only full-length M1 protein provided protection in the subcutaneous invasive disease model.

  15. Development of an inactivated candidate vaccine against Chandipura virus (Rhabdoviridae: Vesiculovirus).

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    Jadi, R S; Sudeep, A B; Barde, P V; Arankalle, V A; Mishra, A C

    2011-06-20

    A Vero cell based vaccine candidate against Chandipura (CHP) virus (Rhabdoviridae: Vesiculovirus), was developed and evaluated for immunogenicity in mice. Virus was purified by ultracentrifugation on 30% glycerol cushion followed by differential centrifugation on 10-60% sucrose gradient and inactivated with β-propio lactone at a concentration of 1:3500. The inactivated product was blended with aluminium phosphate (3%) and immunized 4-week-old Swiss albino mice. Neutralizing antibodies in the range of 1:10 to 160 and 1:80 to 1:320 was detected with 85% and 100% sero-conversion after 2nd and 3rd dose, respectively. All the immunized mice with antibody titer above 1:20 survived live virus challenge. The vaccine candidate has potential to be an efficient vaccine against CHP virus. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Discovery of Novel Leptospirosis Vaccine Candidates Using Reverse and Structural Vaccinology

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    Alan John Alexander McBride

    2017-04-01

    Full Text Available Leptospira spp. are diderm (two membranes bacteria that infect mammals causing leptospirosis, a public health problem with global implications. Thousands of people die every year due to leptospirosis, especially in developing countries with tropical climates. Prophylaxis is difficult due to multiple factors, including the large number of asymptomatic hosts that transmit the bacteria, poor sanitation, increasing numbers of slum dwellers, and the lack of an effective vaccine. Several leptospiral recombinant antigens were evaluated as a replacement for the inactivated (bacterin vaccine; however, success has been limited. A prospective vaccine candidate is likely to be a surface-related protein that can stimulate the host immune response to clear leptospires from blood and organs. In this study, a comprehensive bioinformatics approach based on reverse and structural vaccinology was applied toward the discovery of novel leptospiral vaccine candidates. The Leptospira interrogans serovar Copenhageni strain L1-130 genome was mined in silico for the enhanced identification of conserved β-barrel (βb transmembrane proteins and outer membrane (OM lipoproteins. Orthologs of the prospective vaccine candidates were screened in the genomes of 20 additional Leptospira spp. Three-dimensional structural models, with a high degree of confidence, were created for each of the surface-exposed proteins. Major histocompatibility complex II (MHC-II epitopes were identified, and their locations were mapped on the structural models. A total of 18 βb transmembrane proteins and 8 OM lipoproteins were identified. These proteins were conserved among the pathogenic Leptospira spp. and were predicted to have epitopes for several variants of MHC-II receptors. A structural and functional analysis of the sequence of these surface proteins demonstrated that most βb transmembrane proteins seem to be TonB-dependent receptors associated with transportation. Other proteins

  17. Identification Of Protein Vaccine Candidates Using Comprehensive Proteomic Analysis Strategies

    National Research Council Canada - National Science Library

    Rohrbough, James G

    2007-01-01

    Presented in this dissertation are proteomic analysis studies focused on identifying proteins to be used as vaccine candidates against Coccidioidomycosis, a potentially fatal human pulmonary disease...

  18. Comparative evaluation of phenol and thimerosal as preservatives for a candidate vaccine against American cutaneous leishmaniasis

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    Wilson Mayrink

    2010-02-01

    Full Text Available For decades thimerosal has been used as a preservative in the candidate vaccine for cutaneous leishmaniasis, which was developed by Mayrink et al. The use of thimerosal in humans has been banned due to its mercury content. This study addresses the standardization of phenol as a new candidate vaccine preservative. We have found that the proteolytic activity was abolished when the test was conducted using the candidate vaccine added to merthiolate (MtVac as well as to phenol (PhVac. The Montenegro's skin test conversion rates induced by MtVac and by PhVac was 68.06% and 85.9%, respectively, and these values were statistically significant (p < 0.05. The proliferative response of peripheral mononuclear blood cells shows that the stimulation index of mice immunized with both candidate vaccines was higher than the one in control animals (p < 0.05. The ability of the candidate vaccines to induce protection in C57BL/10 mice against a challenge with infective Leishmania amazonensis promastigotes was tested and the mice immunized with PhVac developed smaller lesions than the mice immunized with MtVac. Electrophoresis of phenol-preserved antigen revealed a number of proteins, which were better preserved in PhVac. These results do in fact encourage the use of phenol for preserving the immunogenic and biochemical properties of the candidate vaccine for cutaneous leishmaniasis.

  19. Biohazard Analysis of Select Biodefense Vaccine Candidates - Venezuelan Equine Encephalitis Virus Strain 3526 and Francisella Tularensis LVS

    International Nuclear Information System (INIS)

    Rao, V.

    2007-01-01

    Biohazard assessment of biodefense vaccine candidates forms the basis for a facility- and activity-specific risk assessment performed to determine the biosafety levels and general safety standards required for biological product development. As a part of our support to the US biodefense vaccine development program, we perform a systematic biohazard assessment of potential vaccine candidates with the primary objective to, (a) Identify and characterize hazard elements associated with the wild type and vaccine strains, (b) Provide biohazard information on the etiologic agent (vaccine candidate) to assess Phase 1 clinical trial facility sites, (c) Provide a baseline to conduct an agent and facility-specific risk assessment at clinical trial facilities interested in performing phase 1 clinical trial, (d) Provide comparative hazard profiles of the vaccine candidates wit MSDS for wild-type to identify and establish appropriate protective biosafety levels, and (e) Support determination of a hazard level to select personal protective equipment as required under the OSHA guidelines. This paper will describe the biohazard analysis of two vaccine candidates, Venezuelan Equine Encephalitis Virus Strain 3526 and Francisella tularensis LVS, a viral and bacterial agent, respectively. As part of the biohazard assessment we preformed a thorough review of published literature on medical pathology, epidemiology, pre-clinical investigational studies, and environmental data on the etiologic agent subtypes and the vaccine candidates. Using standard analytical procedures, the data were then analyzed relative to two intrinsic hazard parameters-health hazard and environmental hazard. Using a weight-of-evidence (WOE) approach, the potential hazards of etiologic agent wild subtypes and vaccine candidates were ranked under three main categories: Public Health Hazard, Environmental Hazard, and Overall Hazard. A WOE scoring system allows for both a determination of the intrinsic hazard of each

  20. Biohazard Analysis of Select Biodefense Vaccine Candidates - Venezuelan Equine Encephalitis Virus Strain 3526 and Francisella Tularensis LVS

    Energy Technology Data Exchange (ETDEWEB)

    Rao, V [National Security Programs, Computer Science Corporation, Alexandria (United States)

    2007-07-01

    Biohazard assessment of biodefense vaccine candidates forms the basis for a facility- and activity-specific risk assessment performed to determine the biosafety levels and general safety standards required for biological product development. As a part of our support to the US biodefense vaccine development program, we perform a systematic biohazard assessment of potential vaccine candidates with the primary objective to, (a) Identify and characterize hazard elements associated with the wild type and vaccine strains, (b) Provide biohazard information on the etiologic agent (vaccine candidate) to assess Phase 1 clinical trial facility sites, (c) Provide a baseline to conduct an agent and facility-specific risk assessment at clinical trial facilities interested in performing phase 1 clinical trial, (d) Provide comparative hazard profiles of the vaccine candidates wit MSDS for wild-type to identify and establish appropriate protective biosafety levels, and (e) Support determination of a hazard level to select personal protective equipment as required under the OSHA guidelines. This paper will describe the biohazard analysis of two vaccine candidates, Venezuelan Equine Encephalitis Virus Strain 3526 and Francisella tularensis LVS, a viral and bacterial agent, respectively. As part of the biohazard assessment we preformed a thorough review of published literature on medical pathology, epidemiology, pre-clinical investigational studies, and environmental data on the etiologic agent subtypes and the vaccine candidates. Using standard analytical procedures, the data were then analyzed relative to two intrinsic hazard parameters-health hazard and environmental hazard. Using a weight-of-evidence (WOE) approach, the potential hazards of etiologic agent wild subtypes and vaccine candidates were ranked under three main categories: Public Health Hazard, Environmental Hazard, and Overall Hazard. A WOE scoring system allows for both a determination of the intrinsic hazard of each

  1. Reduced antibody responses against Plasmodium falciparum vaccine candidate antigens in the presence of Trichuris trichiura

    DEFF Research Database (Denmark)

    Esen, Meral; Mordmüller, Benjamin; de Salazar, Pablo Martinez

    2012-01-01

    BACKGROUND: Helminth infections are highly prevalent in the tropics and may have an effect on immune responses to vaccines due to their immunomodulatory effect. The prevalence of helminth infections in young children, the target group for malaria and most other vaccines, is high. Therefore we...... assessed the influence of helminth infection on vaccine-induced immune responses in a phase I clinical trial of the malaria vaccine candidate GMZ2. METHODS: Twenty Gabonese preschool-age children were vaccinated with GMZ2, a blood stage malaria vaccine candidate. Humoral immune response against the vaccine...... antigens and parasitological status were assessed. Vaccine-specific antibody concentrations and memory B-cell numbers were compared in worm infected and non-infected participants. RESULTS: Antibody response to GMZ2 was 3.4-fold (95% confidence interval: 1.6, 7.4) higher in Trichuris trichiura negative...

  2. Novel Plasmodium falciparum malaria vaccines: evidence-based searching for variant surface antigens as candidates for vaccination against pregnancy-associated malaria

    DEFF Research Database (Denmark)

    Staalsoe, Trine; Jensen, Anja T R; Theander, Thor G

    2002-01-01

    Malaria vaccine development has traditionally concentrated on careful molecular, biochemical, and immunological characterisation of candidate antigens. In contrast, evidence of the importance of identified antigens in immunity to human infection and disease has generally been limited to statistic......Malaria vaccine development has traditionally concentrated on careful molecular, biochemical, and immunological characterisation of candidate antigens. In contrast, evidence of the importance of identified antigens in immunity to human infection and disease has generally been limited...... to statistically significant co-variation with protection rather than on demonstration of causal relationships. We have studied the relationship between variant surface antigen-specific antibodies and clinical protection from Plasmodium falciparum malaria in general, and from pregnancy-associated malaria (PAM......) in particular, to provide robust evidence of a causal link between the two in order to allow efficient and evidence-based identification of candidate antigens for malaria vaccine development....

  3. Generation of a parvovirus B19 vaccine candidate.

    Science.gov (United States)

    Chandramouli, Sumana; Medina-Selby, Angelica; Coit, Doris; Schaefer, Mary; Spencer, Terika; Brito, Luis A; Zhang, Pu; Otten, Gillis; Mandl, Christian W; Mason, Peter W; Dormitzer, Philip R; Settembre, Ethan C

    2013-08-20

    Parvovirus B19 is the causative agent of fifth disease in children, aplastic crisis in those with blood dyscrasias, and hydrops fetalis. Previous parvovirus B19 virus-like-particle (VLP) vaccine candidates were produced by co-infection of insect cells with two baculoviruses, one expressing wild-type VP1 and the other expressing VP2. In humans, the VLPs were immunogenic but reactogenic. We have developed new VLP-based parvovirus B19 vaccine candidates, produced by co-expressing VP2 and either wild-type VP1 or phospholipase-negative VP1 in a regulated ratio from a single plasmid in Saccharomyces cerevisiae. These VLPs are expressed efficiently, are very homogeneous, and can be highly purified. Although VP2 alone can form VLPs, in mouse immunizations, VP1 and the adjuvant MF59 are required to elicit a neutralizing response. Wild-type VLPs and those with phospholipase-negative VP1 are equivalently potent. The purity, homogeneity, yeast origin, and lack of phospholipase activity of these VLPs address potential causes of previously observed reactogenicity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Immunogenicity of mumps virus vaccine candidates matching circulating genotypes in the United States and China.

    Science.gov (United States)

    Zengel, James; Phan, Shannon I; Pickar, Adrian; Xu, Pei; He, Biao

    2017-07-13

    Mumps virus (MuV) causes acute infection in humans with characteristic swelling of the parotid gland. While vaccination has greatly reduced the incidence of MuV infection, there have been multiple large outbreaks of mumps virus (MuV) in highly vaccinated populations. The most common vaccine strain, Jeryl Lynn, belongs to genotype A, which is no longer a circulating genotype. We have developed two vaccine candidates that match the circulating genotypes in the United States (genotype G) and China (genotype F). We found that there was a significant decrease in the ability of the Jeryl Lynn vaccine to produce neutralizing antibody responses to non-matched viruses, when compared to either of our vaccine candidates. Our data suggests that an updated vaccine may allow for better immunity against the circulating MuV genotypes G and F. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. An Approach to Identify and Characterize a Subunit Candidate Shigella Vaccine Antigen.

    Science.gov (United States)

    Pore, Debasis; Chakrabarti, Manoj K

    2016-01-01

    Shigellosis remains a serious issue throughout the developing countries, particularly in children under the age of 5. Numerous strategies have been tested to develop vaccines targeting shigellosis; unfortunately despite several years of extensive research, no safe, effective, and inexpensive vaccine against shigellosis is available so far. Here, we illustrate in detail an approach to identify and establish immunogenic outer membrane proteins from Shigella flexneri 2a as subunit vaccine candidates.

  6. A full-length Plasmodium falciparum recombinant circumsporozoite protein expressed by Pseudomonas fluorescens platform as a malaria vaccine candidate.

    Directory of Open Access Journals (Sweden)

    Amy R Noe

    Full Text Available The circumsporozoite protein (CSP of Plasmodium falciparum is a major surface protein, which forms a dense coat on the sporozoite's surface. Preclinical research on CSP and clinical evaluation of a CSP fragment-based RTS, S/AS01 vaccine have demonstrated a modest degree of protection against P. falciparum, mediated in part by humoral immunity and in part by cell-mediated immunity. Given the partial protective efficacy of the RTS, S/AS01 vaccine in a recent Phase 3 trial, further improvement of CSP-based vaccines is crucial. In this report, we describe the preclinical development of a full-length, recombinant CSP (rCSP-based vaccine candidate against P. falciparum malaria suitable for current Good Manufacturing Practice (cGMP production. Utilizing a novel high-throughput Pseudomonas fluorescens expression platform, we demonstrated greater efficacy of full-length rCSP as compared to N-terminally truncated versions, rapidly down-selected a promising lead vaccine candidate, and developed a high-yield purification process to express immunologically active, intact antigen for clinical trial material production. The rCSP, when formulated with various adjuvants, induced antigen-specific antibody responses as measured by enzyme-linked immunosorbent assay (ELISA and immunofluorescence assay (IFA, as well as CD4+ T-cell responses as determined by ELISpot. The adjuvanted rCSP vaccine conferred protection in mice when challenged with transgenic P. berghei sporozoites containing the P. falciparum repeat region of CSP. Furthermore, heterologous prime/boost regimens with adjuvanted rCSP and an adenovirus type 35-vectored CSP (Ad35CS showed modest improvements in eliciting CSP-specific T-cell responses and anti-malarial protection, depending on the order of vaccine delivery. Collectively, these data support the importance of further clinical development of adjuvanted rCSP, either as a stand-alone product or as one of the components in a heterologous prime

  7. Exoproteome and Secretome Derived Broad Spectrum Novel Drug and Vaccine Candidates in Vibrio cholerae Targeted by Piper betel Derived Compounds

    Science.gov (United States)

    Barh, Debmalya; Barve, Neha; Gupta, Krishnakant; Chandra, Sudha; Jain, Neha; Tiwari, Sandeep; Leon-Sicairos, Nidia; Canizalez-Roman, Adrian; Rodrigues dos Santos, Anderson; Hassan, Syed Shah; Almeida, Síntia; Thiago Jucá Ramos, Rommel; Augusto Carvalho de Abreu, Vinicius; Ribeiro Carneiro, Adriana; de Castro Soares, Siomar; Luiz de Paula Castro, Thiago; Miyoshi, Anderson; Silva, Artur; Kumar, Anil; Narayan Misra, Amarendra; Blum, Kenneth; Braverman, Eric R.; Azevedo, Vasco

    2013-01-01

    Vibrio cholerae is the causal organism of the cholera epidemic, which is mostly prevalent in developing and underdeveloped countries. However, incidences of cholera in developed countries are also alarming. Because of the emergence of new drug-resistant strains, even though several generic drugs and vaccines have been developed over time, Vibrio infections remain a global health problem that appeals for the development of novel drugs and vaccines against the pathogen. Here, applying comparative proteomic and reverse vaccinology approaches to the exoproteome and secretome of the pathogen, we have identified three candidate targets (ompU, uppP and yajC) for most of the pathogenic Vibrio strains. Two targets (uppP and yajC) are novel to Vibrio, and two targets (uppP and ompU) can be used to develop both drugs and vaccines (dual targets) against broad spectrum Vibrio serotypes. Using our novel computational approach, we have identified three peptide vaccine candidates that have high potential to induce both B- and T-cell-mediated immune responses from our identified two dual targets. These two targets were modeled and subjected to virtual screening against natural compounds derived from Piper betel. Seven compounds were identified first time from Piper betel to be highly effective to render the function of these targets to identify them as emerging potential drugs against Vibrio. Our preliminary validation suggests that these identified peptide vaccines and betel compounds are highly effective against Vibrio cholerae. Currently we are exhaustively validating these targets, candidate peptide vaccines, and betel derived lead compounds against a number of Vibrio species. PMID:23382822

  8. Exoproteome and secretome derived broad spectrum novel drug and vaccine candidates in Vibrio cholerae targeted by Piper betel derived compounds.

    Directory of Open Access Journals (Sweden)

    Debmalya Barh

    Full Text Available Vibrio cholerae is the causal organism of the cholera epidemic, which is mostly prevalent in developing and underdeveloped countries. However, incidences of cholera in developed countries are also alarming. Because of the emergence of new drug-resistant strains, even though several generic drugs and vaccines have been developed over time, Vibrio infections remain a global health problem that appeals for the development of novel drugs and vaccines against the pathogen. Here, applying comparative proteomic and reverse vaccinology approaches to the exoproteome and secretome of the pathogen, we have identified three candidate targets (ompU, uppP and yajC for most of the pathogenic Vibrio strains. Two targets (uppP and yajC are novel to Vibrio, and two targets (uppP and ompU can be used to develop both drugs and vaccines (dual targets against broad spectrum Vibrio serotypes. Using our novel computational approach, we have identified three peptide vaccine candidates that have high potential to induce both B- and T-cell-mediated immune responses from our identified two dual targets. These two targets were modeled and subjected to virtual screening against natural compounds derived from Piper betel. Seven compounds were identified first time from Piper betel to be highly effective to render the function of these targets to identify them as emerging potential drugs against Vibrio. Our preliminary validation suggests that these identified peptide vaccines and betel compounds are highly effective against Vibrio cholerae. Currently we are exhaustively validating these targets, candidate peptide vaccines, and betel derived lead compounds against a number of Vibrio species.

  9. Pilot scale production of highly efficacious and stable enterovirus 71 vaccine candidates.

    Directory of Open Access Journals (Sweden)

    Ai-Hsiang Chou

    Full Text Available BACKGROUND: Enterovirus 71 (EV71 has caused several epidemics of hand, foot and mouth diseases (HFMD in Asia and now is being recognized as an important neurotropic virus. Effective medications and prophylactic vaccine against EV71 infection are urgently needed. Based on the success of inactivated poliovirus vaccine, a prototype chemically inactivated EV71 vaccine candidate has been developed and currently in human phase 1 clinical trial. PRINCIPAL FINDING: In this report, we present the development of a serum-free cell-based EV71 vaccine. The optimization at each step of the manufacturing process was investigated, characterized and quantified. In the up-stream process development, different commercially available cell culture media either containing serum or serum-free was screened for cell growth and virus yield using the roller-bottle technology. VP-SFM serum-free medium was selected based on the Vero cell growth profile and EV71 virus production. After the up-stream processes (virus harvest, diafiltration and concentration, a combination of gel-filtration liquid chromatography and/or sucrose-gradient ultracentrifugation down-stream purification processes were investigated at a pilot scale of 40 liters each. Although the combination of chromatography and sucrose-gradient ultracentrifugation produced extremely pure EV71 infectious virus particles, the overall yield of vaccine was 7-10% as determined by a VP2-based quantitative ELISA. Using chromatography as the downstream purification, the virus yield was 30-43%. To retain the integrity of virus neutralization epitopes and the stability of the vaccine product, the best virus inactivation was found to be 0.025% formalin-treatment at 37 °C for 3 to 6 days. Furthermore, the formalin-inactivated virion vaccine candidate was found to be stable for >18 months at 4 °C and a microgram of viral proteins formulated with alum adjuvant could induce strong virus-neutralizing antibody responses in mice

  10. Pilot scale production of highly efficacious and stable enterovirus 71 vaccine candidates.

    Science.gov (United States)

    Chou, Ai-Hsiang; Liu, Chia-Chyi; Chang, Cheng-Peng; Guo, Meng-Shin; Hsieh, Shih-Yang; Yang, Wen-Hsueh; Chao, Hsin-Ju; Wu, Chien-Long; Huang, Ju-Lan; Lee, Min-Shi; Hu, Alan Yung-Chi; Lin, Sue-Chen; Huang, Yu-Yun; Hu, Mei-Hua; Chow, Yen-Hung; Chiang, Jen-Ron; Chang, Jui-Yuan; Chong, Pele

    2012-01-01

    Enterovirus 71 (EV71) has caused several epidemics of hand, foot and mouth diseases (HFMD) in Asia and now is being recognized as an important neurotropic virus. Effective medications and prophylactic vaccine against EV71 infection are urgently needed. Based on the success of inactivated poliovirus vaccine, a prototype chemically inactivated EV71 vaccine candidate has been developed and currently in human phase 1 clinical trial. In this report, we present the development of a serum-free cell-based EV71 vaccine. The optimization at each step of the manufacturing process was investigated, characterized and quantified. In the up-stream process development, different commercially available cell culture media either containing serum or serum-free was screened for cell growth and virus yield using the roller-bottle technology. VP-SFM serum-free medium was selected based on the Vero cell growth profile and EV71 virus production. After the up-stream processes (virus harvest, diafiltration and concentration), a combination of gel-filtration liquid chromatography and/or sucrose-gradient ultracentrifugation down-stream purification processes were investigated at a pilot scale of 40 liters each. Although the combination of chromatography and sucrose-gradient ultracentrifugation produced extremely pure EV71 infectious virus particles, the overall yield of vaccine was 7-10% as determined by a VP2-based quantitative ELISA. Using chromatography as the downstream purification, the virus yield was 30-43%. To retain the integrity of virus neutralization epitopes and the stability of the vaccine product, the best virus inactivation was found to be 0.025% formalin-treatment at 37 °C for 3 to 6 days. Furthermore, the formalin-inactivated virion vaccine candidate was found to be stable for >18 months at 4 °C and a microgram of viral proteins formulated with alum adjuvant could induce strong virus-neutralizing antibody responses in mice, rats, rabbits, and non-human primates. These

  11. Immunogenicity of novel mumps vaccine candidates generated by genetic modification.

    Science.gov (United States)

    Xu, Pei; Chen, Zhenhai; Phan, Shannon; Pickar, Adrian; He, Biao

    2014-03-01

    Mumps is a highly contagious human disease, characterized by lateral or bilateral nonsuppurative swelling of the parotid glands and neurological complications that can result in aseptic meningitis or encephalitis. A mumps vaccination program implemented since the 1960s reduced mumps incidence by more than 99% and kept the mumps case numbers as low as hundreds of cases per year in the United States before 2006. However, a large mumps outbreak occurred in vaccinated populations in 2006 and again in 2009 in the United States, raising concerns about the efficacy of the vaccination program. Previously, we have shown that clinical isolate-based recombinant mumps viruses lacking expression of either the V protein (rMuVΔV) or the SH protein (rMuVΔSH) are attenuated in a neurovirulence test using newborn rat brains (P. Xu et al., Virology 417:126-136, 2011, http://dx.doi.org/10.1016/j.virol.2011.05.003; P. Xu et al., J. Virol. 86:1768-1776, 2012, http://dx.doi.org/10.1128/JVI.06019-11) and may be good candidates for vaccine development. In this study, we examined immunity induced by rMuVΔSH and rMuVΔV in mice. Furthermore, we generated recombinant mumps viruses lacking expression of both the V protein and the SH protein (rMuVΔSHΔV). Analysis of rMuVΔSHΔV indicated that it was stable in tissue culture cell lines. Importantly, rMuVΔSHΔV was immunogenic in mice, indicating that it is a promising candidate for mumps vaccine development.

  12. Ten Leading Causes of Death and Injury

    Science.gov (United States)

    ... Overdose Traumatic Brain Injury Violence Prevention Ten Leading Causes of Death and Injury Recommend on Facebook Tweet Share Compartir ... in Hospital Emergency Departments, United States – 2014 Leading Causes of Death Charts Causes of Death by Age Group 2016 [ ...

  13. Comparative testing of six antigen-based malaria vaccine candidates directed toward merozoite-stage Plasmodium falciparum

    DEFF Research Database (Denmark)

    Arnot, David E; Cavanagh, David R; Remarque, Edmond J

    2008-01-01

    Immunogenicity testing of Plasmodium falciparum antigens being considered as malaria vaccine candidates was undertaken in rabbits. The antigens compared were recombinant baculovirus MSP-1(19) and five Pichia pastoris candidates, including two versions of MSP-1(19), AMA-1 (domains I and II), AMA-1......G concentrations. The two P. pastoris-produced MSP-1(19)-induced IgGs conferred the lowest growth inhibition. Comparative analysis of immunogenicity of vaccine antigens can be used to prioritize candidates before moving to expensive GMP production and clinical testing. The assays used have given discriminating...

  14. Identification of Novel Vaccine Candidates against Campylobacter through Reverse Vaccinology

    Directory of Open Access Journals (Sweden)

    Marine Meunier

    2016-01-01

    Full Text Available Campylobacteriosis is the most prevalent bacterial foodborne gastroenteritis affecting humans in the European Union. Human cases are mainly due to Campylobacter jejuni or Campylobacter coli, and contamination is associated with the handling and/or consumption of poultry meat. In fact, poultry constitutes the bacteria’s main reservoir. A promising way of decreasing the incidence of campylobacteriosis in humans would be to decrease avian colonization. Poultry vaccination is of potential for this purpose. However, despite many studies, there is currently no vaccine available on the market to reduce the intestinal Campylobacter load in chickens. It is essential to identify and characterize new vaccine antigens. This study applied the reverse vaccinology approach to detect new vaccine candidates. The main criteria used to select immune proteins were localization, antigenicity, and number of B-epitopes. Fourteen proteins were identified as potential vaccine antigens. In vitro and in vivo experiments now need to be performed to validate the immune and protective power of these newly identified antigens.

  15. Vaccination of dogs with six different candidate leishmaniasis vaccines composed of a chimerical recombinant protein containing ribosomal and histone protein epitopes in combination with different adjuvants.

    Science.gov (United States)

    Poot, J; Janssen, L H M; van Kasteren-Westerneng, T J; van der Heijden-Liefkens, K H A; Schijns, V E J C; Heckeroth, A

    2009-07-16

    Chimerical protein "Q", composed of antigenic ribosomal and histone sequences, in combination with live BCG is a promising canine leishmaniasis vaccine candidate; one of the few vaccine candidates that have been tested successfully in dogs. Unfortunately, live BCG is not an appropriate adjuvant for commercial application due to safety problems in dogs. In order to find a safe adjuvant with similar efficacy to live BCG, muramyl dipeptide, aluminium hydroxide, Matrix C and killed Propionibacterium acnes in combination with either E. coli- or baculovirus-produced recombinant JPCM5_Q protein were tested. Groups of five or seven dogs were vaccinated with six different adjuvant-antigen combinations and challenged with a high dose intravenous injection of Leishmania infantum JPC strain promastigotes. All candidate vaccines proved to be safe, and both humoral and cellular responses to the recombinant proteins were detected at the end of the prime-boost vaccination scheme. However, clinical and parasitological data obtained during the 10 month follow-up period indicated that protection was not induced by either of the six candidate vaccines. Although no direct evidence was obtained, our data suggest that live BCG may have a significant protective effect against challenge with L. infantum in dogs.

  16. SARS CTL vaccine candidates; HLA supertype-, genome-wide scanning and biochemical validation

    DEFF Research Database (Denmark)

    Sylvester-Hvid, C; Nielsen, M; Lamberth, K

    2004-01-01

    . Exact knowledge of how the immune system handles protein antigens would allow for the identification of such linear sequences directly from genomic/proteomic sequence information (Lauemoller et al., Rev Immunogenet 2001: 2: 477-91). The latter was recently established when a causative coronavirus (SARS...... of the HLA supertypes and identified almost 100 potential vaccine candidates. These should be further validated in SARS survivors and used for vaccine formulation. We suggest that immunobioinformatics may become a fast and valuable tool in rational vaccine design....

  17. SARS CTL vaccine candidates; HLA supertype-, genome-wide scanning and biochemical validation

    DEFF Research Database (Denmark)

    Sylvester-Hvid, C.; Nielsen, Morten; Lamberth, K.

    2004-01-01

    . Exact knowledge of how the immune system handles protein antigens would allow for the identification of such linear sequences directly, from genomic/proteomic sequence information (Lauemoller et al., Rev Immunogenet 2001: 2: 477-91). The latter was recently established when a causative coronavirus (SARS...... of the HLA supertypes and identified almost 100 potential vaccine candidates. These should be further validated in SARS survivors and used for vaccine formulation. We suggest that immunobioinformatics may become a fast and valuable tool in rational vaccine design....

  18. Safety and immunogenicity of GMZ2 - a MSP3-GLURP fusion protein malaria vaccine candidate

    DEFF Research Database (Denmark)

    Esen, Meral; Kremsner, Peter G; Schleucher, Regina

    2009-01-01

    Malaria is a major public health problem in Sub-Saharan Africa. In highly endemic regions infants, children and pregnant women are mostly affected. An effective malaria vaccine would complement existing malaria control strategies because it can be integrated in existing immunization programs easily....... Here we present the results of the first phase Ia clinical trial of GMZ2 adjuvanted in aluminium hydroxide. GMZ2 is a malaria vaccine candidate, designed upon the rationale to induce immune responses against asexual blood stages of Plasmodium falciparum similar to those encountered in semi...... is a safe and immunogenic malaria vaccine candidate suitable for further clinical development....

  19. Characterization of Two Metal Binding Lipoproteins as Vaccine Candidates for Enterococcal Infections.

    Science.gov (United States)

    Romero-Saavedra, Felipe; Laverde, Diana; Budin-Verneuil, Aurélie; Muller, Cécile; Bernay, Benoit; Benachour, Abdellah; Hartke, Axel; Huebner, Johannes

    2015-01-01

    Enterococcus faecium and faecalis are Gram-positive opportunistic pathogens that have become leading causes of nosocomial infections over the last decades. Especially multidrug resistant enterococci have become a challenging clinical problem worldwide. Therefore, new treatment options are needed and the identification of alternative targets for vaccine development has emerged as a feasible alternative to fight the infections caused by these pathogens. We extrapolate the transcriptomic data from a mice peritonitis infection model in E. faecalis to identify putative up-regulated surface proteins under infection conditions in E. faecium. After the bionformatic analyses two metal binding lipoproteins were identified to have a high homology (>72%) between the two species, the manganese ABC transporter substrate-binding lipoprotein (PsaAfm,) and the zinc ABC transporter substrate-binding lipoprotein (AdcAfm). These candidate lipoproteins were overexpressed in Escherichia coli and purified. The recombinant proteins were used to produce rabbit polyclonal antibodies that were able to induce specific opsonic antibodies that mediated killing of the homologous strain E. faecium E155 as well as clinical strains E. faecium E1162, Enterococcus faecalis 12030, type 2 and type 5. Mice were passively immunized with the antibodies raised against recombinant lipoproteins, showing significant reduction of colony counts in mice livers after the bacterial challenge and demonstrating the efficacy of these metal binding lipoproteins as promising vaccine candidates to treat infections caused by these enterococcal pathogens. Overall, our results demonstrate that these two metal binding lipoproteins elicited specific, opsonic and protective antibodies, with an extensive cross-reactivity and serotype-independent coverage among these two important nocosomial pathogens. Pointing these two protein antigens as promising immunogens, that can be used as single components or as carrier proteins

  20. Extended Preclinical Safety, Efficacy and Stability Testing of a Live-attenuated Chikungunya Vaccine Candidate.

    Directory of Open Access Journals (Sweden)

    Kenneth S Plante

    Full Text Available We recently described a new, live-attenuated vaccine candidate for chikungunya (CHIK fever, CHIKV/IRES. This vaccine was shown to be well attenuated, immunogenic and efficacious in protecting against CHIK virus (CHIKV challenge of mice and nonhuman primates. To further evaluate its preclinical safety, we compared CHIKV/IRES distribution and viral loads in interferon-α/β receptor-incompetent A129 mice to another CHIK vaccine candidate, 181/clone25, which proved highly immunogenic but mildly reactive in human Phase I/II clinical trials. Compared to wild-type CHIK virus, (wt-CHIKV, both vaccines generated lower viral loads in a wide variety of tissues and organs, including the brain and leg muscle, but CHIKV/IRES exhibited marked restrictions in dissemination and viral loads compared to 181/clone25, and was never found outside the blood, spleen and muscle. Unlike wt-CHIKV, which caused disrupted splenic architecture and hepatic lesions, histopathological lesions were not observed in animals infected with either vaccine strain. To examine the stability of attenuation, both vaccines were passaged 5 times intracranially in infant A129 mice, then assessed for changes in virulence by comparing parental and passaged viruses for footpad swelling, weight stability and survival after subcutaneous infection. Whereas strain 181/clone25 p5 underwent a significant increase in virulence as measured by weight loss (from 30% and mortality (from 0 to 100%, CHIKV/IRES underwent no detectible change in any measure of virulence (no significant weight loss and no mortality. These data indicate greater nonclinical safety of the CHIKV/IRES vaccine candidate compared to 181/clone25, further supporting its eligibility for human testing.

  1. [Ten years of human papillomavirus vaccination. From dermatology to oncology via infectology].

    Science.gov (United States)

    Moraga-Llop, Fernando A

    2018-05-01

    Human papillomavirus (HPV) was first identified in dermatology, and it was subsequently demonstrated that is was required for the development of uterine cervical cancer and other tumours, after a persistent infection by any of its oncogenic genotypes. Ten years ago, the most common infections and cancers associated with HPV could be prevented by immunisation with 2vaccines, one bivalent, and another tetravalent, and having just marketed a nonavalent one. During the period 2007-2008, the HPV vaccine was included in the Autonomous Communities vaccination calendar, and it is the second vaccine, after that of Hepatitis B, that prevents cancer. In these 10 years that these vaccines have been available the knowledge has progressed and there have been significant advances in vaccination strategies, as well as in the indications and recommendations. These include, lowering the age in the vaccination schedule, prescribing of 2doses at 9 years and at 13-14 years, systematic vaccination of the male in some countries, immunisation of the woman after adolescence, implementation of vaccination programmes in developed countries, prevention of other cancers, recommendations for vaccinations for populations at high risk of HPV infection, scientific evidence on the impact and effectiveness of vaccination, and confirmation of the safety of these vaccines, with more than 270 million doses administered, as has already been observed in clinical trials. The role of health professionals is essential to achieve and maintain high vaccine coverage. Copyright © 2017 Asociación Española de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

  2. Strategic evaluation of vaccine candidate antigens for the prevention of Visceral Leishmaniasis.

    Science.gov (United States)

    Duthie, Malcolm S; Favila, Michelle; Hofmeyer, Kimberley A; Tutterrow, Yeung L; Reed, Steven J; Laurance, John D; Picone, Alessandro; Guderian, Jeffrey; Bailor, H Remy; Vallur, Aarthy C; Liang, Hong; Mohamath, Raodoh; Vergara, Julie; Howard, Randall F; Coler, Rhea N; Reed, Steven G

    2016-05-27

    Infection with Leishmania parasites results in a range of clinical manifestations and outcomes, the most severe of which is visceral leishmaniasis (VL). Vaccination will likely provide the most effective long-term control strategy, as the large number of vectors and potential infectious reservoirs renders sustained interruption of Leishmania parasite transmission extremely difficult. Selection of the best vaccine is complicated because, although several vaccine antigen candidates have been proposed, they have emerged following production in different platforms. To consolidate the information that has been generated into a single vaccine platform, we expressed seven candidates as recombinant proteins in E. coli. After verifying that each recombinant protein could be recognized by VL patients, we evaluated their protective efficacy against experimental L. donovani infection of mice. Administration in formulation with the Th1-potentiating adjuvant GLA-SE indicated that each antigen could elicit antigen-specific Th1 responses that were protective. Considering the ability to reduce parasite burden along with additional factors such as sequence identity across Leishmania species, we then generated a chimeric fusion protein comprising a combination of the 8E, p21 and SMT proteins. This E. coli -expressed fusion protein was also demonstrated to protect against L. donovani infection. These data indicate a novel recombinant vaccine antigen with the potential for use in VL control programs. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  3. Engineering and expression of a human rotavirus candidate vaccine in Nicotiana benthamiana.

    Science.gov (United States)

    Pêra, Francisco F P G; Mutepfa, David L R; Khan, Ayesha M; Els, Johann H; Mbewana, Sandiswa; van Dijk, Alberdina A A; Rybicki, Edward P; Hitzeroth, Inga I

    2015-12-02

    Human rotaviruses are the main cause of severe gastroenteritis in children and are responsible for over 500 000 deaths annually. There are two live rotavirus vaccines currently available, one based on human rotavirus serotype G1P[8], and the other a G1-G4 P[8] pentavalent vaccine. However, the recent emergence of the G9 and other novel rotavirus serotypes in Africa and Asia has prompted fears that current vaccines might not be fully effective against these new varieties. We report an effort to develop an affordable candidate rotavirus vaccine against the new emerging G9P[6] (RVA/Human-wt/ZAF/GR10924/1999/G9P[6]) strain. The vaccine is based on virus-like particles which are both highly immunogenic and safe. The vaccine candidate was produced in Nicotiana benthamiana by transient expression, as plants allow rapid production of antigens at lower costs, without the risk of contamination by animal pathogens. Western blot analysis of plant extracts confirmed the successful expression of two rotavirus capsid proteins, VP2 and VP6. These proteins assembled into VLPs resembling native rotavirus particles when analysed by transmission electron microscopy (TEM). Expression of the rotavirus glycoprotein VP7 and the spike protein VP4 was also tried. However, VP7 expression caused plant wilting during the course of the time trial and expression could never be detected for either protein. We therefore created three fusion proteins adding the antigenic part of VP4 (VP8*) to VP6 in an attempt to produce more appropriately immunogenic particles. Fusion protein expression in tobacco plants was detected by western blot using anti-VP6 and anti-VP4 antibodies, but no regular particles were observed by TEM, even when co-expressed with VP2. Our results suggest that the rotavirus proteins produced in N. benthamiana are candidates for a subunit vaccine specifically for the G9P[6] rotavirus strain. This could be more effective in developing countries, thereby possibly providing a higher

  4. Identification and development of a promising novel mumps vaccine candidate strain.

    Science.gov (United States)

    Liang, Yan; Ma, Shaohui; Liu, Longding; Zhao, Hongling; Wang, Lichun; Jiang, Li; Xie, Zhongping; Dong, Chenghong; Li, Qihan

    2010-12-01

    Mumps epidemics are usually caused by airborne transmission of mumps virus (MuV) and have high morbidity in non-immunized children. Epidemiological studies in many regions of China show that the genotype F viral strain is the most prevalent. However, the genotype A strain is currently used to prepare vaccines. Regional epidemiological MuV data suggest a significant application for the development of live attenuated mumps vaccines targeting specific genotypes. This article reports the isolation and culture of a genotype F MuV candidate strain that could be used to prepare a live attenuated mumps vaccine. This strain is shown to have good immunological efficacy and stability in neurovirulence evaluations. This work should facilitate the implementation of mumps vaccination in mainland China by targeting the most prevalent MuV genotype, genotype F. Copyright © 2010 Institut Pasteur. Published by Elsevier SAS. All rights reserved.

  5. Evaluation of novel oral vaccine candidates and validation of a caprine model of Johne's disease

    Science.gov (United States)

    Hines, Murray E.; Turnquist, Sue E.; Ilha, Marcia R. S.; Rajeev, Sreekumari; Jones, Arthur L.; Whittington, Lisa; Bannantine, John P.; Barletta, Raúl G.; Gröhn, Yrjö T.; Katani, Robab; Talaat, Adel M.; Li, Lingling; Kapur, Vivek

    2014-01-01

    Johne's disease (JD) caused by Mycobacterium avium subspecies paratuberculosis (MAP) is a major threat to the dairy industry and possibly some cases of Crohn's disease in humans. A MAP vaccine that reduced of clinical disease and/or reduced fecal shedding would aid in the control of JD. The objectives of this study were (1) to evaluate the efficacy of 5 attenuated strains of MAP as vaccine candidates compared to a commercial control vaccine using the protocol proposed by the Johne's Disease Integrated Program (JDIP) Animal Model Standardization Committee (AMSC), and (2) to validate the AMSC Johne's disease goat challenge model. Eighty goat kids were vaccinated orally twice at 8 and 10 weeks of age with an experimental vaccine or once subcutaneously at 8 weeks with Silirum® (Zoetis), or a sham control oral vaccine at 8 and 10 weeks. Kids were challenged orally with a total of approximately 1.44 × 109 CFU divided in two consecutive daily doses using MAP ATCC-700535 (K10-like bovine isolate). All kids were necropsied at 13 months post-challenge. Results indicated that the AMSC goat challenge model is a highly efficient and valid model for JD challenge studies. None of the experimental or control vaccines evaluated prevented MAP infection or eliminated fecal shedding, although the 329 vaccine lowered the incidence of infection, fecal shedding, tissue colonization and reduced lesion scores, but less than the control vaccine. Based on our results the relative performance ranking of the experimental live-attenuated vaccines evaluated, the 329 vaccine was the best performer, followed by the 318 vaccine, then 316 vaccine, 315 vaccine and finally the 319 vaccine was the worst performer. The subcutaneously injected control vaccine outperformed the orally-delivered mutant vaccine candidates. Two vaccines (329 and 318) do reduce presence of JD gross and microscopic lesions, slow progression of disease, and one vaccine (329) reduced fecal shedding and tissue colonization. PMID

  6. Evaluation of Novel Oral Vaccine Candidates and Validation of a Caprine Model of Johne's Disease

    Directory of Open Access Journals (Sweden)

    Murray E. Hines

    2014-03-01

    Full Text Available Johne’s disease (JD caused by Mycobacterium avium subspecies paratuberculosis (MAP is a major threat to the dairy industry and possibly some cases of Crohn’s disease in humans. A MAP vaccine that reduced of clinical disease and/or reduced fecal shedding would aid in the control of JD. The objectives of this study were 1 to evaluate the efficacy of 5 attenuated strains of MAP as vaccine candidates compared to a commercial control vaccine using the protocol proposed by the Johne’s Disease Integrated Program (JDIP Animal Model Standardization Committee (AMSC, and 2 to validate the AMSC Johne’s disease goat challenge model. Eighty goat kids were vaccinated orally twice at 8 and 10 weeks of age with an experimental vaccine or once subcutaneously at 8 weeks with Silirum® (Zoetis, or a sham control oral vaccine at 8 and 10 weeks. Kids were challenged orally with a total of approximately 1.44 X 10^9 CFU divided in 2 consecutive daily doses using MAP ATCC-700535 (K10-like bovine isolate. All kids were necropsied at 13 months post challenge. Results indicated that the AMSC goat challenge model is a highly efficient and valid model for JD challenge studies. None of the experimental or control vaccines evaluated prevented MAP infection or eliminated fecal shedding, although the 329 vaccine lowered the incidence of infection, fecal shedding, tissue colonization and reduced lesion scores, but less than the control vaccine. Based on our results the relative performance ranking of the experimental live-attenuated vaccines evaluated, the 329 vaccine was the best performer, followed by the 318 vaccine, then 316 vaccine, 315 vaccine and finally the 319 vaccine was the worst performer. The subcutaneously injected control vaccine outperformed the orally-delivered mutant vaccine candidates. Two vaccines (329 and 318 do reduce presence of JD gross and microscopic lesions, slow progression of disease, and one vaccine (329 reduced fecal shedding and tissue

  7. Egg-Independent Influenza Vaccines and Vaccine Candidates

    Directory of Open Access Journals (Sweden)

    Ilaria Manini

    2017-07-01

    Full Text Available Vaccination remains the principal way to control seasonal infections and is the most effective method of reducing influenza-associated morbidity and mortality. Since the 1940s, the main method of producing influenza vaccines has been an egg-based production process. However, in the event of a pandemic, this method has a significant limitation, as the time lag from strain isolation to final dose formulation and validation is six months. Indeed, production in eggs is a relatively slow process and production yields are both unpredictable and highly variable from strain to strain. In particular, if the next influenza pandemic were to arise from an avian influenza virus, and thus reduce the egg-laying hen population, there would be a shortage of embryonated eggs available for vaccine manufacturing. Although the production of egg-derived vaccines will continue, new technological developments have generated a cell-culture-based influenza vaccine and other more recent platforms, such as synthetic influenza vaccines.

  8. Ebola Virus Disease Candidate Vaccines Under Evaluation in Clinical Trials

    Science.gov (United States)

    2016-06-02

    evidence that oral vaccines fail in populations with disturbed microbiota, poor nutrition , and high intestinal inflammation [102-104]. Additionally...countermeasure development against Ebola virus disease becoming a global public- health priority. This review summarizes the status quo of candidate...members of the mononegaviral family Filoviridae) cause two diseases recognized by the World Health Organization (WHO): Ebola virus disease (EVD) can be

  9. Identification Of Protein Vaccine Candidates Using Comprehensive Proteomic Analysis Strategies

    Science.gov (United States)

    2007-12-01

    that fascinating fungus known as Coccidioides. I also want to thank the UA Mass Spectrometry Facility and the UA Proteomics Consortium, especially...W. & N. N. Kav. 2006. The proteome of the phytopathogenic fungus Sclerotinia sclerotiorum. Proteomics 6: 5995-6007. 127. de Godoy, L. M., J. V...IDENTIFICATION OF PROTEIN VACCINE CANDIDATES USING COMPREHENSIVE PROTEOMIC ANALYSIS STRATEGIES by James G. Rohrbough

  10. Rapid strategy for screening by pyrosequencing of influenza virus reassortants--candidates for live attenuated vaccines.

    Science.gov (United States)

    Shcherbik, Svetlana V; Pearce, Nicholas C; Levine, Marnie L; Klimov, Alexander I; Villanueva, Julie M; Bousse, Tatiana L

    2014-01-01

    Live attenuated influenza vaccine viruses (LAIVs) can be generated by classical reassortment of gene segments between a cold adapted, temperature sensitive and attenuated Master Donor Virus (MDV) and a seasonal wild-type (wt) virus. The vaccine candidates contain hemagglutinin (HA) and neuraminidase (NA) genes derived from the circulating wt viruses and the remaining six genes derived from the MDV strains. Rapid, efficient selection of the viruses with 6∶2 genome compositions from the large number of genetically different viruses generated during reassortment is essential for the biannual production schedule of vaccine viruses. This manuscript describes a new approach for the genotypic analysis of LAIV reassortant virus clones based on pyrosequencing. LAIV candidate viruses were created by classical reassortment of seasonal influenza A (H3N2) (A/Victoria/361/2011, A/Ohio/02/2012, A/Texas/50/2012) or influenza A (H7N9) (A/Anhui/1/2013) wt viruses with the MDV A/Leningrad/134/17/57(H2N2). Using strain-specific pyrosequencing assays, mixed gene variations were detected in the allantoic progenies during the cloning procedure. The pyrosequencing analysis also allowed for estimation of the relative abundance of segment variants in mixed populations. This semi-quantitative approach was used for selecting specific clones for the subsequent cloning procedures. The present study demonstrates that pyrosequencing analysis is a useful technique for rapid and reliable genotyping of reassortants and intermediate clones during the preparation of LAIV candidates, and can expedite the selection of vaccine virus candidates.

  11. Rapid strategy for screening by pyrosequencing of influenza virus reassortants--candidates for live attenuated vaccines.

    Directory of Open Access Journals (Sweden)

    Svetlana V Shcherbik

    Full Text Available BACKGROUND: Live attenuated influenza vaccine viruses (LAIVs can be generated by classical reassortment of gene segments between a cold adapted, temperature sensitive and attenuated Master Donor Virus (MDV and a seasonal wild-type (wt virus. The vaccine candidates contain hemagglutinin (HA and neuraminidase (NA genes derived from the circulating wt viruses and the remaining six genes derived from the MDV strains. Rapid, efficient selection of the viruses with 6∶2 genome compositions from the large number of genetically different viruses generated during reassortment is essential for the biannual production schedule of vaccine viruses. METHODOLOGY/PRINCIPAL FINDINGS: This manuscript describes a new approach for the genotypic analysis of LAIV reassortant virus clones based on pyrosequencing. LAIV candidate viruses were created by classical reassortment of seasonal influenza A (H3N2 (A/Victoria/361/2011, A/Ohio/02/2012, A/Texas/50/2012 or influenza A (H7N9 (A/Anhui/1/2013 wt viruses with the MDV A/Leningrad/134/17/57(H2N2. Using strain-specific pyrosequencing assays, mixed gene variations were detected in the allantoic progenies during the cloning procedure. The pyrosequencing analysis also allowed for estimation of the relative abundance of segment variants in mixed populations. This semi-quantitative approach was used for selecting specific clones for the subsequent cloning procedures. CONCLUSIONS/SIGNIFICANCE: The present study demonstrates that pyrosequencing analysis is a useful technique for rapid and reliable genotyping of reassortants and intermediate clones during the preparation of LAIV candidates, and can expedite the selection of vaccine virus candidates.

  12. Effect of the pre-erythrocytic candidate malaria vaccine RTS,S/AS01E on blood stage immunity in young children

    DEFF Research Database (Denmark)

    Bejon, Philip; Cook, Jackie; Bergmann-Leitner, Elke

    2011-01-01

    (See the article by Greenhouse et al, on pages 19-26.) Background. RTS,S/AS01(E) is the lead candidate malaria vaccine and confers pre-erythrocytic immunity. Vaccination may therefore impact acquired immunity to blood-stage malaria parasites after natural infection. Methods. We measured, by enzyme......, MSP-1(42), and MSP-3 antibody concentrations and no significant change in GIA. Increasing anti-merozoite antibody concentrations and GIA were prospectively associated with increased risk of clinical malaria. Conclusions. Vaccination with RTS,S/AS01E reduces exposure to blood-stage parasites and, thus......-linked immunosorbent assay, antibodies to 4 Plasmodium falciparum merozoite antigens (AMA-1, MSP-1(42), EBA-175, and MSP-3) and by growth inhibitory activity (GIA) using 2 parasite clones (FV0 and 3D7) at 4 times on 860 children who were randomized to receive with RTS,S/AS01(E) or a control vaccine. Results. Antibody...

  13. The Supersymmetric Top-Ten Lists

    OpenAIRE

    Haber, Howard E.

    1993-01-01

    Ten reasons are given why supersymmetry is the leading candidate for physics beyond the Standard Model. Ultimately, the experimental discovery of supersymmetric particles at future colliders will determine whether supersymmetry is relevant for TeV scale physics. The grand hope of supersymmetry enthusiasts is to connect TeV scale supersymmetry with Planck scale physics. The ten most pressing theoretical problems standing in the way of this goal are briefly described.

  14. Surface display of Clonorchis sinensis enolase on Bacillus subtilis spores potentializes an oral vaccine candidate.

    Science.gov (United States)

    Wang, Xiaoyun; Chen, Wenjun; Tian, Yanli; Mao, Qiang; Lv, Xiaoli; Shang, Mei; Li, Xuerong; Yu, Xinbing; Huang, Yan

    2014-03-10

    Clonorchis sinensis (C. sinensis) infections remain the common public health problem in freshwater fish consumption areas. New effective prevention strategies are still the urgent challenges to control this kind of foodborne infectious disease. The biochemical importance and biological relevance render C. sinensis enolase (Csenolase) as a potential vaccine candidate. In the present study, we constructed Escherichia coli/Bacillus subtilis shuttle genetic engineering system and investigated the potential of Csenolase as an oral vaccine candidate for C. sinensis prevention in different immunization routes. Our results showed that, compared with control groups, both recombinant Csenolase protein and nucleic acid could induce a mixed IgG1/IgG2a immune response when administrated subcutaneously (Psinensis infection. Csenolase derived oral vaccine conferred worm reduction rate and egg reduction rate at 60.07% (Psinensis prevention. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Rotavirus vaccines: an overview.

    OpenAIRE

    Midthun, K; Kapikian, A Z

    1996-01-01

    Rotavirus vaccine development has focused on the delivery of live attenuated rotavirus strains by the oral route. The initial "Jennerian" approach involving bovine (RIT4237, WC3) or rhesus (RRV) rotavirus vaccine candidates showed that these vaccines were safe, well tolerated, and immunogenic but induced highly variable rates of protection against rotavirus diarrhea. The goal of a rotavirus vaccine is to prevent severe illness that can lead to dehydration in infants and young children in both...

  16. Immune response profiles of calves following vaccination with live BCG and inactivated Mycobacterium bovis vaccine candidates.

    Directory of Open Access Journals (Sweden)

    E M D L van der Heijden

    Full Text Available Conventional control and eradication strategies for bovine tuberculosis (BTB face tremendous difficulties in developing countries; countries with wildlife reservoirs, a complex wildlife-livestock-human interface or a lack of veterinary and veterinary public health surveillance. Vaccination of cattle and other species might in some cases provide the only suitable control strategy for BTB, while in others it may supplement existing test-and-slaughter schemes. However, the use of live BCG has several limitations and the global rise of HIV/AIDS infections has furthermore warranted the exploration of inactivated vaccine preparations. The aim of this study was to compare the immune response profiles in response to parenteral vaccination with live BCG and two inactivated vaccine candidates in cattle. Twenty-four mixed breed calves (Bos taurus aged 4-6 months, were allocated to one of four groups and vaccinated sub-cutaneously with live M. bovis BCG (Danish 1331, formalin-inactivated M. bovis BCG, heat-killed M. bovis or PBS/Montanide™ (control. Interferon-γ responsiveness and antibody production were measured prior to vaccination and at weekly intervals thereafter for twelve weeks. At nine weeks post-priming, animals were skin tested using tuberculins and MTBC specific protein cocktails and subsequently challenged through intranodular injection of live M. bovis BCG. The animals in the heat-killed M. bovis group demonstrated strong and sustained cell-mediated and humoral immune responses, significantly higher than the control group in response to vaccination, which may indicate a protective immune profile. Animals in this group showed reactivity to the skin test reagents, confirming good vaccine take. Lastly, although not statistically significant, recovery of BCG after challenge was lowest in the heat-killed M. bovis group. In conclusion, the parenteral heat-killed M. bovis vaccine proved to be clearly immunogenic in cattle in the present study

  17. Cell biological characterization of the malaria vaccine candidate trophozoite exported protein 1.

    Directory of Open Access Journals (Sweden)

    Caroline Kulangara

    Full Text Available In a genome-wide screen for alpha-helical coiled coil motifs aiming at structurally defined vaccine candidates we identified PFF0165c. This protein is exported in the trophozoite stage and was named accordingly Trophozoite exported protein 1 (Tex1. In an extensive preclinical evaluation of its coiled coil peptides Tex1 was identified as promising novel malaria vaccine candidate providing the rational for a comprehensive cell biological characterization of Tex1. Antibodies generated against an intrinsically unstructured N-terminal region of Tex1 and against a coiled coil domain were used to investigate cytological localization, solubility and expression profile. Co-localization experiments revealed that Tex1 is exported across the parasitophorous vacuole membrane and located to Maurer's clefts. Change in location is accompanied by a change in solubility: from a soluble state within the parasite to a membrane-associated state after export to Maurer's clefts. No classical export motifs such as PEXEL, signal sequence/anchor or transmembrane domain was identified for Tex1.

  18. Ensayo preclínico de la vacuna candid #1 producida en Argentina contra la Fiebre Hemorrágica Argentina Preclinical assay of Candid #1 vaccine against Argentine Hemorrhagic Fever made in Argentina

    Directory of Open Access Journals (Sweden)

    Ana M. Ambrosio

    2005-08-01

    Full Text Available Se comparó en cobayos la seguridad, inmunogenicidad y eficacia protectora de un lote de vacuna Candid #1(C#1 fabricada en Estados Unidos de América (EE.UU. y distintos lotes de la misma vacuna fabricados en Argentina (Arg. El lote TSI 5-1-92 (EE.UU. y los lotes Exp Nº 3, 7A y 8A (Arg fueron inoculados (0.5 ml, IM en cobayos de 250-400 g. Para cada ensayo diez animales recibieron solución fisiológica y sirvieron como control. Todos fueron desafiados con la cepa patógena P23790 de virus Junin. Se registró: a temperatura rectal, b peso corporal, c presencia de anticuerpos neutralizantes (AcNT pre y post-vacunación, d respuesta al desafío. Todos los animales vacunados desarrollaron AcNT anti virus Junin (rango = 40- 81920 y sobrevivieron al desafío. En cada grupo control 8/10 animales murieron (día 23.3 ± 5.4 post-desafío. Los cobayos resultaron idénticamente protegidos de una descarga letal de virus Junin por la vacuna importada y los diferentes lotes de C#1 producidos en Argentina.Candid #1 vaccine against Argentine Hemorrhagic Fever produced in USA versus lots of the same vaccine made in Argentina were compared in guinea pigs regarding safety, immunogenicity and protective efficacy against a challenge with pathogenic Junin virus. Lots Nº Exp 3, 7A and 8A of Argentine origin as well as lot TSI 5-1-92 from USA were inoculated in guinea pigs of 250-400 g in two consecutive assays. Ten animals inoculated with saline performed as normal controls in each experiment. Parameters studied were: a temperature; b body weight; c neutralizing antibodies to Junin virus; d response to viral challenge. Animals gained weight and remained normothermic up to the challenge. Guinea pigs that received Candid #1 from any manufacturer elicited neutralizing antibodies to Junin virus (titles from 40 to 81920 and survived to challenge whilst 8/10 animals died in each control group. Data presented demonstrated that Candid #1 vaccines from USA or Argentine

  19. Construction of a trivalent candidate vaccine against Shigella species with DNA recombination

    Institute of Scientific and Technical Information of China (English)

    王恒樑; 冯尔玲; 林云; 廖翔; 金明; 黄留玉; 苏国富; 黄翠芬

    2002-01-01

    In this work asd gene of Shigella flexneri 2a strain T32 was replaced by Vibrio cholerae toxin B subunit (ctxB) gene with DNA recombination in vivo and in vitro. The resulting derivative of T32, designed as FWL01, could stably express CtxB, but its growth in LB medium depended on the presence of diaminopimelic acid (DAP). Then form I plasmid of Shigella sonnei strain S7 was labeled with strain T32 asd gene and mobilized into FWL01. Thus a trivalent candidate oral vaccine strain, designed as FSW01, was constructed. In this candidate strain, a balanced-lethal system was constituted between the host strain and the form I plasmid expressing S. sonnei O antigen. Therefore the candidate strain can express stably not only its own O antigen but also CtxB and O antigen of S. sonnei in the absence of any antibiotic. Experiments showed that FSW01 did not invade HeLa cells or cause keratoconjunctivitis in guinea pigs. However, rabbits immunized FSW01 can elicit significant immune responses. In mice and rhesus monkey models, vaccinated animals were protected against the challenges of wild S. flexneri 2a strain 2457T and S. sonnei strain S9.

  20. A multi-country study of dengue vaccination strategies with Dengvaxia and a future vaccine candidate in three dengue-endemic countries: Vietnam, Thailand, and Colombia.

    Science.gov (United States)

    Lee, Jung-Seok; Lourenço, José; Gupta, Sunetra; Farlow, Andrew

    2018-04-19

    The dengue vaccination era began when Dengvaxia (CYD-TDV) became available in 2016. In addition, several second-generation vaccine candidates are currently in phase 3 trials, suggesting that a broader availability of dengue vaccines may be possible in the near future. Advancing on the recent WHO-SAGE recommendations for the safe and effective use of CYD-TDV at the regional level on average, this study investigates the vaccination impacts and cost-effectiveness of CYD-TDV and of a hypothetical new vaccine candidate (NVC) in a country-specific manner for three endemic countries: Vietnam, Thailand, and Colombia. The vaccination impacts of CYD-TDV and NVC were derived by fitting the empirical seroprevalence rates of 9 year olds into an individual-based meta-population transmission model, previously used for the WHO-SAGE working group. The disability-adjusted life years were estimated by applying country-specific parametric values. The cost-effectiveness analyses of four intervention strategies in combination with routine and catch-up campaigns were compared for both vaccines to inform decision makers regarding the most suitable immunization program in each of the three countries. Both CYD-TDV and NVC could be cost-effective at the DALY threshold cost of $2000 depending upon vaccination costs. With CYD-TDV, targeting 9 year olds in routine vaccination programs and 10-29 year olds as a one-off catch-up campaign was the most cost-effective strategy in all three countries. With NVC, while the most cost-effective strategy was to vaccinate 9-29 and 9-18 year olds in Vietnam and Thailand respectively, vaccinating younger age cohorts between 1 and 5 years old in Colombia was more cost-effective than other strategies. Given that three countries will soon face decisions regarding whether and how to incorporate CYD-TDV or future dengue vaccines into their budget-constrained national immunization programs, the current study outcomes can be used to help decision makers

  1. A Rapid and Improved Method to Generate Recombinant Dengue Virus Vaccine Candidates.

    Science.gov (United States)

    Govindarajan, Dhanasekaran; Guan, Liming; Meschino, Steven; Fridman, Arthur; Bagchi, Ansu; Pak, Irene; ter Meulen, Jan; Casimiro, Danilo R; Bett, Andrew J

    2016-01-01

    Dengue is one of the most important mosquito-borne infections accounting for severe morbidity and mortality worldwide. Recently, the tetravalent chimeric live attenuated Dengue vaccine Dengvaxia® was approved for use in several dengue endemic countries. In general, live attenuated vaccines (LAV) are very efficacious and offer long-lasting immunity against virus-induced disease. Rationally designed LAVs can be generated through reverse genetics technology, a method of generating infectious recombinant viruses from full length cDNA contained in bacterial plasmids. In vitro transcribed (IVT) viral RNA from these infectious clones is transfected into susceptible cells to generate recombinant virus. However, the generation of full-length dengue virus cDNA clones can be difficult due to the genetic instability of viral sequences in bacterial plasmids. To circumvent the need for a single plasmid containing a full length cDNA, in vitro ligation of two or three cDNA fragments contained in separate plasmids can be used to generate a full-length dengue viral cDNA template. However, in vitro ligation of multiple fragments often yields low quality template for IVT reactions, resulting in inconsistent low yield RNA. These technical difficulties make recombinant virus recovery less efficient. In this study, we describe a simple, rapid and efficient method of using LONG-PCR to recover recombinant chimeric Yellow fever dengue (CYD) viruses as potential dengue vaccine candidates. Using this method, we were able to efficiently generate several viable recombinant viruses without introducing any artificial mutations into the viral genomes. We believe that the techniques reported here will enable rapid and efficient recovery of recombinant flaviviruses for evaluation as vaccine candidates and, be applicable to the recovery of other RNA viruses.

  2. Advances and challenges in malaria vaccine development.

    Science.gov (United States)

    Crompton, Peter D; Pierce, Susan K; Miller, Louis H

    2010-12-01

    Malaria caused by Plasmodium falciparum remains a major public health threat, especially among children and pregnant women in Africa. An effective malaria vaccine would be a valuable tool to reduce the disease burden and could contribute to elimination of malaria in some regions of the world. Current malaria vaccine candidates are directed against human and mosquito stages of the parasite life cycle, but thus far, relatively few proteins have been studied for potential vaccine development. The most advanced vaccine candidate, RTS,S, conferred partial protection against malaria in phase II clinical trials and is currently being evaluated in a phase III trial in Africa. New vaccine targets need to be identified to improve the chances of developing a highly effective malaria vaccine. A better understanding of the mechanisms of naturally acquired immunity to malaria may lead to insights for vaccine development.

  3. Rotavirus vaccines

    Directory of Open Access Journals (Sweden)

    Kang G

    2006-01-01

    Full Text Available Rotavirus, the most common cause of severe diarrhea and a leading cause of mortality in children, has been a priority target for vaccine development for the past several years. The first rotavirus vaccine licensed in the United States was withdrawn because of an association of the vaccine with intussusception. However, the need for a vaccine is greatest in the developing world, because the benefits of preventing deaths due to rotavirus disease are substantially greater than the risk of intussusception. Early vaccines were based on animal strains. More recently developed and licenced vaccines are either animal-human reassortants or are based on human strains. In India, two candidate vaccines are in the development process, but have not yet reached efficacy trials. Many challenges regarding vaccine efficacy and safety remain. In addition to completing clinical evaluations of vaccines in development in settings with the highest disease burden and virus diversity, there is also a need to consider alternative vaccine development strategies.

  4. Evaluation of Lethal Giant Larvae as a Schistosomiasis Vaccine Candidate

    Directory of Open Access Journals (Sweden)

    Yufan Cao

    2016-01-01

    Full Text Available Schistosomiasis is a neglected tropical disease of humans, and it is considered to be the second most devastating parasitic disease after malaria. Eggs produced by normally developed female worms are important in the transmission of the parasite, and they responsible for the pathogenesis of schistosomiasis. The tumor suppressor gene lethal giant larvae (lgl has an essential function in establishing apical-basal cell polarity, cell proliferation, differentiation, and tissue organization. In our earlier study, downregulation of the lgl gene induced a significant reduction in the egg hatching rate of Schistosoma japonicum (Sj eggs. In this study, the Sjlgl gene was used as a vaccine candidate against schistosomiasis, and vaccination achieved and maintained a stable reduction of the egg hatching rate, which is consistent with previous studies, in addition to reducing the worm burden and liver egg burden in some trials.

  5. In vivo electroporation enhances the immunogenicity of an HIV-1 DNA vaccine candidate in healthy volunteers.

    Directory of Open Access Journals (Sweden)

    Sandhya Vasan

    Full Text Available DNA-based vaccines have been safe but weakly immunogenic in humans to date.We sought to determine the safety, tolerability, and immunogenicity of ADVAX, a multigenic HIV-1 DNA vaccine candidate, injected intramuscularly by in vivo electroporation (EP in a Phase-1, double-blind, randomized placebo-controlled trial in healthy volunteers. Eight volunteers each received 0.2 mg, 1 mg, or 4 mg ADVAX or saline placebo via EP, or 4 mg ADVAX via standard intramuscular injection at weeks 0 and 8. A third vaccination was administered to eleven volunteers at week 36. EP was safe, well-tolerated and considered acceptable for a prophylactic vaccine. EP delivery of ADVAX increased the magnitude of HIV-1-specific cell mediated immunity by up to 70-fold over IM injection, as measured by gamma interferon ELISpot. The number of antigens to which the response was detected improved with EP and increasing dosage. Intracellular cytokine staining analysis of ELISpot responders revealed both CD4+ and CD8+ T cell responses, with co-secretion of multiple cytokines.This is the first demonstration in healthy volunteers that EP is safe, tolerable, and effective in improving the magnitude, breadth and durability of cellular immune responses to a DNA vaccine candidate.ClinicalTrials.gov NCT00545987.

  6. In silico analysis to identify vaccine candidates common to multiple serotypes of Shigella and evaluation of their immunogenicity

    KAUST Repository

    Pahil, Sapna

    2017-08-02

    Shigellosis or bacillary dysentery is an important cause of diarrhea, with the majority of the cases occurring in developing countries. Considering the high disease burden, increasing antibiotic resistance, serotype-specific immunity and the post-infectious sequelae associated with shigellosis, there is a pressing need of an effective vaccine against multiple serotypes of the pathogen. In the present study, we used bio-informatics approach to identify antigens shared among multiple serotypes of Shigella spp. This approach led to the identification of many immunogenic peptides. The five most promising peptides based on MHC binding efficiency were a putative lipoprotein (EL PGI I), a putative heat shock protein (EL PGI II), Spa32 (EL PGI III), IcsB (EL PGI IV) and a hypothetical protein (EL PGI V). These peptides were synthesized and the immunogenicity was evaluated in BALB/c mice by ELISA and cytokine assays. The putative heat shock protein (HSP) and the hypothetical protein elicited good humoral response, whereas putative lipoprotein, Spa32 and IcsB elicited good T-cell response as revealed by increased IFN-γ and TNF-α cytokine levels. The patient sera from confirmed cases of shigellosis were also evaluated for the presence of peptide specific antibodies with significant IgG and IgA antibodies against the HSP and the hypothetical protein, bestowing them as potential future vaccine candidates. The antigens reported in this study are novel and have not been tested as vaccine candidates against Shigella. This study offers time and cost-effective way of identifying unprecedented immunogenic antigens to be used as potential vaccine candidates. Moreover, this approach should easily be extendable to find new potential vaccine candidates for other pathogenic bacteria.

  7. In silico analysis to identify vaccine candidates common to multiple serotypes of Shigella and evaluation of their immunogenicity.

    Science.gov (United States)

    Pahil, Sapna; Taneja, Neelam; Ansari, Hifzur Rahman; Raghava, G P S

    2017-01-01

    Shigellosis or bacillary dysentery is an important cause of diarrhea, with the majority of the cases occurring in developing countries. Considering the high disease burden, increasing antibiotic resistance, serotype-specific immunity and the post-infectious sequelae associated with shigellosis, there is a pressing need of an effective vaccine against multiple serotypes of the pathogen. In the present study, we used bio-informatics approach to identify antigens shared among multiple serotypes of Shigella spp. This approach led to the identification of many immunogenic peptides. The five most promising peptides based on MHC binding efficiency were a putative lipoprotein (EL PGI I), a putative heat shock protein (EL PGI II), Spa32 (EL PGI III), IcsB (EL PGI IV) and a hypothetical protein (EL PGI V). These peptides were synthesized and the immunogenicity was evaluated in BALB/c mice by ELISA and cytokine assays. The putative heat shock protein (HSP) and the hypothetical protein elicited good humoral response, whereas putative lipoprotein, Spa32 and IcsB elicited good T-cell response as revealed by increased IFN-γ and TNF-α cytokine levels. The patient sera from confirmed cases of shigellosis were also evaluated for the presence of peptide specific antibodies with significant IgG and IgA antibodies against the HSP and the hypothetical protein, bestowing them as potential future vaccine candidates. The antigens reported in this study are novel and have not been tested as vaccine candidates against Shigella. This study offers time and cost-effective way of identifying unprecedented immunogenic antigens to be used as potential vaccine candidates. Moreover, this approach should easily be extendable to find new potential vaccine candidates for other pathogenic bacteria.

  8. In silico analysis to identify vaccine candidates common to multiple serotypes of Shigella and evaluation of their immunogenicity

    KAUST Repository

    Pahil, Sapna; Taneja, Neelam; Ansari, Hifzur Rahman; Raghava, G. P. S.

    2017-01-01

    Shigellosis or bacillary dysentery is an important cause of diarrhea, with the majority of the cases occurring in developing countries. Considering the high disease burden, increasing antibiotic resistance, serotype-specific immunity and the post-infectious sequelae associated with shigellosis, there is a pressing need of an effective vaccine against multiple serotypes of the pathogen. In the present study, we used bio-informatics approach to identify antigens shared among multiple serotypes of Shigella spp. This approach led to the identification of many immunogenic peptides. The five most promising peptides based on MHC binding efficiency were a putative lipoprotein (EL PGI I), a putative heat shock protein (EL PGI II), Spa32 (EL PGI III), IcsB (EL PGI IV) and a hypothetical protein (EL PGI V). These peptides were synthesized and the immunogenicity was evaluated in BALB/c mice by ELISA and cytokine assays. The putative heat shock protein (HSP) and the hypothetical protein elicited good humoral response, whereas putative lipoprotein, Spa32 and IcsB elicited good T-cell response as revealed by increased IFN-γ and TNF-α cytokine levels. The patient sera from confirmed cases of shigellosis were also evaluated for the presence of peptide specific antibodies with significant IgG and IgA antibodies against the HSP and the hypothetical protein, bestowing them as potential future vaccine candidates. The antigens reported in this study are novel and have not been tested as vaccine candidates against Shigella. This study offers time and cost-effective way of identifying unprecedented immunogenic antigens to be used as potential vaccine candidates. Moreover, this approach should easily be extendable to find new potential vaccine candidates for other pathogenic bacteria.

  9. In silico analysis to identify vaccine candidates common to multiple serotypes of Shigella and evaluation of their immunogenicity.

    Directory of Open Access Journals (Sweden)

    Sapna Pahil

    Full Text Available Shigellosis or bacillary dysentery is an important cause of diarrhea, with the majority of the cases occurring in developing countries. Considering the high disease burden, increasing antibiotic resistance, serotype-specific immunity and the post-infectious sequelae associated with shigellosis, there is a pressing need of an effective vaccine against multiple serotypes of the pathogen. In the present study, we used bio-informatics approach to identify antigens shared among multiple serotypes of Shigella spp. This approach led to the identification of many immunogenic peptides. The five most promising peptides based on MHC binding efficiency were a putative lipoprotein (EL PGI I, a putative heat shock protein (EL PGI II, Spa32 (EL PGI III, IcsB (EL PGI IV and a hypothetical protein (EL PGI V. These peptides were synthesized and the immunogenicity was evaluated in BALB/c mice by ELISA and cytokine assays. The putative heat shock protein (HSP and the hypothetical protein elicited good humoral response, whereas putative lipoprotein, Spa32 and IcsB elicited good T-cell response as revealed by increased IFN-γ and TNF-α cytokine levels. The patient sera from confirmed cases of shigellosis were also evaluated for the presence of peptide specific antibodies with significant IgG and IgA antibodies against the HSP and the hypothetical protein, bestowing them as potential future vaccine candidates. The antigens reported in this study are novel and have not been tested as vaccine candidates against Shigella. This study offers time and cost-effective way of identifying unprecedented immunogenic antigens to be used as potential vaccine candidates. Moreover, this approach should easily be extendable to find new potential vaccine candidates for other pathogenic bacteria.

  10. Conjugating recombinant proteins to Pseudomonas aeruginosa ExoProtein A: a strategy for enhancing immunogenicity of malaria vaccine candidates

    OpenAIRE

    Qian, Feng; Wu, Yimin; Muratova, Olga; Zhou, Hong; Dobrescu, Gelu; Duggan, Peter; Lynn, Lambert; Song, Guanhong; Zhang, Yanling; Reiter, Karine; MacDonald, Nicholas; Narum, David L.; Long, Carole A.; Miller, Louis H.; Saul, Allan

    2007-01-01

    Conjugation of polysaccharides to carrier proteins has been a successful approach for producing safe and effective vaccines. In an attempt to increase the immunogenicity of two malarial vaccine candidate proteins of Plasmodium falciparum, apical membrane antigen 1 (AMA1) for blood stage vaccines and surface protein 25 (Pfs25) for mosquito stage vaccines, each was chemically conjugated to the mutant, nontoxic Pseudomonas aeruginosa ExoProtein A (rEPA). AMA1 is a large (66 kD) relatively good i...

  11. Successes and failures in human tuberculosis vaccine development.

    Science.gov (United States)

    Zenteno-Cuevas, Roberto

    2017-12-01

    Tuberculosis (TB) is an infectious disease caused mainly by Mycobacterium tuberculosis. In 2016, the WHO estimated 10.5 million new cases and 1.8 million deaths, making this disease the leading cause of death by an infectious agent. The current and projected TB situation necessitates the development of new vaccines with improved attributes compared to the traditional BCG method. Areas covered: In this review, the authors describe the most promising candidate vaccines against TB and discuss additional key elements in vaccine development, such as animal models, new adjuvants and immunization routes and new strategies for the identification of candidate vaccines. Expert opinion: At present, around 13 candidate vaccines for TB are in the clinical phase of evaluation; however, there is still no substitute for the BCG vaccine. One major impediment to developing an effective vaccine is our lack of understanding of several of the mechanisms associated with infection and the immune response against TB. However, the recent implementation of an entirely new set of technological advances will facilitate the proposal of new candidates. Finally, development of a new vaccine will require a major coordination of effort in order to achieve its effective administration to the people most in need of it.

  12. Strategies & recent development of transmission-blocking vaccines against Plasmodium falciparum

    Directory of Open Access Journals (Sweden)

    Neha Chaturvedi

    2016-01-01

    Full Text Available Transmission blocking malaria vaccines are aimed to block the development and maturity of sexual stages of parasite within mosquitoes. The vaccine candidate antigens (Pfs25, Pfs48/45, Pfs230 that have shown transmission blocking immunity in model systems are in different stages of development. These antigens are immunogenic with limited genetic diversity. Pfs25 is a leading candidate and currently in phase I clinical trial. Efforts are now focused on the cost-effective production of potent antigens using safe adjuvants and optimization of vaccine delivery system that are capable of inducing strong immune responses. This review addresses the potential usefulness, development strategies, challenges, clinical trials and current status of Plasmodium falciparum sexual stage malaria vaccine candidate antigens for the development of transmission-blocking vaccines.

  13. Broad blockade antibody responses in human volunteers after immunization with a multivalent norovirus VLP candidate vaccine: immunological analyses from a phase I clinical trial.

    Directory of Open Access Journals (Sweden)

    Lisa C Lindesmith

    2015-03-01

    Full Text Available Human noroviruses (NoVs are the primary cause of acute gastroenteritis and are characterized by antigenic variation between genogroups and genotypes and antigenic drift of strains within the predominant GII.4 genotype. In the context of this diversity, an effective NoV vaccine must elicit broadly protective immunity. We used an antibody (Ab binding blockade assay to measure the potential cross-strain protection provided by a multivalent NoV virus-like particle (VLP candidate vaccine in human volunteers.Sera from ten human volunteers immunized with a multivalent NoV VLP vaccine (genotypes GI.1/GII.4 were analyzed for IgG and Ab blockade of VLP interaction with carbohydrate ligand, a potential correlate of protective immunity to NoV infection and illness. Immunization resulted in rapid rises in IgG and blockade Ab titers against both vaccine components and additional VLPs representing diverse strains and genotypes not represented in the vaccine. Importantly, vaccination induced blockade Ab to two novel GII.4 strains not in circulation at the time of vaccination or sample collection. GII.4 cross-reactive blockade Ab titers were more potent than responses against non-GII.4 VLPs, suggesting that previous exposure history to this dominant circulating genotype may impact the vaccine Ab response. Further, antigenic cartography indicated that vaccination preferentially activated preexisting Ab responses to epitopes associated with GII.4.1997. Study interpretations may be limited by the relevance of the surrogate neutralization assay and the number of immunized participants evaluated.Vaccination with a multivalent NoV VLP vaccine induces a broadly blocking Ab response to multiple epitopes within vaccine and non-vaccine NoV strains and to novel antigenic variants not yet circulating at the time of vaccination. These data reveal new information about complex NoV immune responses to both natural exposure and to vaccination, and support the potential

  14. The fimbrial protein FlfA from Gallibacterium anatis is a virulence factor and vaccine candidate

    DEFF Research Database (Denmark)

    Bager, Ragnhild Jørgensen; Nesta, Barbara; Pors, Susanne Elisabeth

    2013-01-01

    in the natural chicken host. Furthermore, protection against G. anatis 12656-12 could be induced by immunizing chickens with recombinant FlfA. Finally, in vitro expression of FlfA homologs was observed in a genetically diverse set of G. anatis strains, suggesting the potential of FlfA as a serotype-independent...... vaccine candidate This is the first study describing a fimbrial subunit protein of G. anatis with a clear potential as a vaccine antigen....

  15. Vacuna contra la fiebre hemorrágica argentina Candid#1 producida en la Argentina: Inmunogenicidad y seguridad Candid#1 vaccine against Argentine Hemorrhagic Fever produced in Argentina: Immunogenicity and safety

    Directory of Open Access Journals (Sweden)

    Delia A. Enria

    2010-06-01

    Full Text Available Se realizó un estudio clínico en 946 voluntarios humanos sanos, donde se comparó la vacuna Candid#1 producida en Argentina con la elaborada en EE.UU., que había sido utilizada en estudios previos. Como objetivo primario se evaluó la equivalencia en la eficacia utilizando como marcador subrogante a la inmunogenicidad medida por detección de anticuerpos neutralizantes. Como objetivo secundario se evaluó la equivalencia en inocuidad comparando las tasas de reacciones adversas. Ambas vacunas mostraron una tasa equivalente de inmunogenicidad ligeramente superior al 95.5%, que es la eficacia estimada para Candid #1 en estudios previos. No se observaron eventos adversos graves relacionados con la vacuna. Los eventos adversos generales considerados relacionados fueron de escasa significación clínica y de resolución espontánea o con tratamiento sintomático; se presentaron en los receptores de ambas vacunas en tasas equivalentes (29.9% para la vacuna fabricada en la Argentina y 35.0% para la fabricada en EE.UU., e incluyeron: cefalea, decaimiento, mialgias, plaquetopenia leve (A clinical study in 946 human volunteers was done to compare Candid #1 vaccine manufactured in Argentina with the vaccine produced in USA that had been previously used. The efficacy was evaluated using immunogenicity measured by the detection of neutralizing antibodies as a subrogate marker. Safety was evaluated comparing the rate of adverse events. Both vaccines showed a comparable rate of seroconversion, slighty higher than the efficacy estimated from previous studies (95.5%. There were no severe adverse events related to the vaccines. The general events considered related to the vaccines were not clinically relevant and disappeared either spontaneously or with symptomatic treatment. Similar rates of adverse events (29.9% for the Argentine vaccine and 35.0% for the USA vaccine were found for both vaccines. These included: headache, weakness, myalgias, mild low blood

  16. A Rapid and Improved Method to Generate Recombinant Dengue Virus Vaccine Candidates.

    Directory of Open Access Journals (Sweden)

    Dhanasekaran Govindarajan

    Full Text Available Dengue is one of the most important mosquito-borne infections accounting for severe morbidity and mortality worldwide. Recently, the tetravalent chimeric live attenuated Dengue vaccine Dengvaxia® was approved for use in several dengue endemic countries. In general, live attenuated vaccines (LAV are very efficacious and offer long-lasting immunity against virus-induced disease. Rationally designed LAVs can be generated through reverse genetics technology, a method of generating infectious recombinant viruses from full length cDNA contained in bacterial plasmids. In vitro transcribed (IVT viral RNA from these infectious clones is transfected into susceptible cells to generate recombinant virus. However, the generation of full-length dengue virus cDNA clones can be difficult due to the genetic instability of viral sequences in bacterial plasmids. To circumvent the need for a single plasmid containing a full length cDNA, in vitro ligation of two or three cDNA fragments contained in separate plasmids can be used to generate a full-length dengue viral cDNA template. However, in vitro ligation of multiple fragments often yields low quality template for IVT reactions, resulting in inconsistent low yield RNA. These technical difficulties make recombinant virus recovery less efficient. In this study, we describe a simple, rapid and efficient method of using LONG-PCR to recover recombinant chimeric Yellow fever dengue (CYD viruses as potential dengue vaccine candidates. Using this method, we were able to efficiently generate several viable recombinant viruses without introducing any artificial mutations into the viral genomes. We believe that the techniques reported here will enable rapid and efficient recovery of recombinant flaviviruses for evaluation as vaccine candidates and, be applicable to the recovery of other RNA viruses.

  17. An assessment of enterotoxigenic Escherichia coli and Shigella vaccine candidates for infants and children.

    Science.gov (United States)

    Walker, Richard I

    2015-02-18

    Despite improvements to water quality, sanitation, and the implementation of current prevention and treatment interventions, diarrhea remains a major cause of illness and death, especially among children less than five years of age in the developing world. Rotavirus vaccines have already begun making a real impact on diarrhea, but several more enteric vaccines will be necessary to achieve broader reductions of illness and death. Among the many causes of diarrheal disease, enterotoxigenic Escherichia coli (ETEC) and Shigella are the two most important bacterial pathogens for which there are no currently licensed vaccines. Vaccines against these two pathogens could greatly reduce the impact of disease caused by these infections. This review describes the approaches to ETEC and Shigella vaccines that are currently under development, including a range of both cellular and subunit approaches for each pathogen. In addition, the review discusses strategies for maximizing the potential benefit of these vaccines, which includes the feasibility of co-administration, consolidation, and combination of vaccine candidates, as well as issues related to effective administration of enteric vaccines to infants. Recent impact studies indicate that ETEC and Shigella vaccines could significantly benefit global public health. Either vaccine, particularly if they could be combined together or with another enteric vaccine, would be an extremely valuable tool for saving lives and promoting the health of infants and children in the developing world, as well as potentially providing protection to travelers and military personnel visiting endemic areas. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Oral administration of live Shigella vaccine candidates in rhesus monkeys show no evidence of competition for colonization and immunogenicity between different serotypes.

    Science.gov (United States)

    Ranallo, R T; Kaminski, R; Baqar, S; Dutta, M; Lugo-Roman, L A; Boren, T; Barnoy, S; Venkatesan, M M

    2014-03-26

    Live oral monovalent Shigella flexneri 2a vaccine candidates as well as bivalent formulations with Shigella sonnei were evaluated in a rhesus monkey model for colonization and immunogenicity. Freshly harvested suspensions of S. flexneri 2a vaccine candidates WRSf2G12 and WRSf2G15 as well as S. sonnei vaccine candidate WRSs3 were nasogastrically administered to groups of rhesus monkeys, Macaca mulatta, either in a monovalent form or when combined with each other. The animals were monitored daily for physical well-being, stools were subjected to quantitative colony immunoblot assays for bacterial excretion and blood and stools were evaluated for humoral and mucosal immune responses. No clinical symptoms were noted in any group of animals and the vaccine candidates were excreted robustly for 48-72h without significant changes in either the magnitude or duration of excretion when given as a monovalent or as bivalent mixtures. Similarly, immunological interferences were not apparent in the magnitude of humoral and mucosal immune responses observed toward Shigella-specific antigens when monkeys were fed monovalent or bivalent formulations. These results predict that a multivalent live oral vaccine of more than one serotype can have a favorable outcome for protection against shigellosis. Published by Elsevier Ltd.

  19. The Capricious Nature of Bacterial Pathogens: Phasevarions and Vaccine Development

    Directory of Open Access Journals (Sweden)

    Aimee Tan

    2016-12-01

    Full Text Available Infectious diseases are a leading cause of morbidity and mortality worldwide, and vaccines are one of the most successful and cost-effective tools for disease prevention. One of the key considerations for rational vaccine development is the selection of appropriate antigens. Antigens must induce a protective immune response, and this response should be directed to stably expressed antigens so the target microbe can always be recognized by the immune system. Antigens with variable expression, due to environmental signals or phase variation (i.e., high frequency, random switching of expression, are not ideal vaccine candidates because variable expression could lead to immune evasion. Phase variation is often mediated by the presence of highly mutagenic simple tandem DNA repeats, and genes containing such sequences can be easily identified, and their use discounted as vaccine antigens reconsidered. Recent research has identified phase variably expressed DNA methyltransferases that act as global epigenetic regulators. These phase variable regulons, known as phasevarions, are associated with altered virulence phenotypes and/or expression of vaccine candidates. As such, genes encoding candidate vaccine antigens that have no obvious mechanism of phase variation may be subject to indirect, epigenetic control as part of a phasevarion. Bioinformatic and experimental studies are required to elucidate the distribution and mechanism of action of these DNA methyltransferases, and most importantly, whether they mediate epigenetic regulation of potential and current vaccine candidates. This process is essential to define the stably expressed antigen target profile of bacterial pathogens and thereby facilitate efficient, rational selection of vaccine antigens.

  20. Lipoprotein NMB0928 from Neisseria meningitidis serogroup B as a novel vaccine candidate.

    Science.gov (United States)

    Delgado, Maité; Yero, Daniel; Niebla, Olivia; González, Sonia; Climent, Yanet; Pérez, Yusleydis; Cobas, Karem; Caballero, Evelín; García, Darien; Pajón, Rolando

    2007-12-05

    Polysaccharide-based vaccines for serogroup B Neisseria meningitidis have failed to induce protective immunity. As a result, efforts to develop vaccines for serogroup B meningococcal disease have mostly focused on outer membrane proteins (OMP). Vaccine candidates based on meningococcal OMP have emerged in the form of outer membrane vesicles (OMVs) or, more recently, purified recombinant proteins, as alternative strategies for serogroup B vaccine development. In our group, the protein composition of the Cuban OMVs-based vaccine VA-MENGOC-BC was elucidated using two-dimensional gel electrophoresis and mass spectrometry. The proteomic map of this product allowed the identification of new putative protective proteins not previously reported as components of an antimeningococcal vaccine. In the present study, we have determined the immunogenicity and protective capacity of NMB0928, one of those proteins present in the OMVs. The antigen was obtained as a recombinant protein in Escherichia coli, purified and used to immunize mice. The antiserum produced against the protein was capable to recognize the natural protein in different meningococcal strains by whole-cell ELISA and Western blotting. After immunization, recombinant NMB0928 induced bactericidal antibodies, and when the protein was administered inserted into liposomes, the elicited antibodies were protective in the infant rat model. These results suggest that NMB0928 is a novel antigen worth to be included in a broadly protective meningococcal vaccine.

  1. Construction and characterization of human rotavirus recombinant VP8* subunit parenteral vaccine candidates.

    Science.gov (United States)

    Wen, Xiaobo; Cao, Dianjun; Jones, Ronald W; Li, Jianping; Szu, Shousun; Hoshino, Yasutaka

    2012-09-21

    Two currently licensed live oral rotavirus vaccines (Rotarix® and RotaTeq®) are highly efficacious against severe rotavirus diarrhea. However, the efficacy of such vaccines in selected low-income African and Asian countries is much lower than that in middle or high-income countries. Additionally, these two vaccines have recently been associated with rare case of intussusception in vaccinated infants. We developed a novel recombinant subunit parenteral rotavirus vaccine which may be more effective in low-income countries and also avert the potential problem of intussusception. Truncated recombinant VP8* (ΔVP8*) protein of human rotavirus strain Wa P[8], DS-1 P[4] or 1076 P[6] expressed in Escherichia coli was highly soluble and was generated in high yield. Guinea pigs hyperimmunized intramuscularly with each of the ΔVP8* proteins (i.e., P[8], P[4] or P[6]) developed high levels of homotypic as well as variable levels of heterotypic neutralizing antibodies. Moreover, the selected ΔVP8* proteins when administered to mice at a clinically relevant dosage, route and schedule, elicited high levels of serum anti-VP8* IgG and/or neutralizing antibodies. Our data indicated that the ΔVP8* proteins may be a plausible additional candidate as new parenteral rotavirus vaccines. Published by Elsevier Ltd.

  2. Satisfactory safety and immunogenicity of MSP3 malaria vaccine candidate in Tanzanian children aged 12–24 months

    Directory of Open Access Journals (Sweden)

    Segeja Method D

    2009-07-01

    Full Text Available Abstract Background Development and deployment of an effective malaria vaccine would complement existing malaria control measures. A blood stage malaria vaccine candidate, Merozoite Surface Protein-3 (MSP3, produced as a long synthetic peptide, has been shown to be safe in non-immune and semi-immune adults. A phase Ib dose-escalating study was conducted to assess the vaccine's safety and immunogenicity in children aged 12 to 24 months in Korogwe, Tanzania (ClinicalTrials.gov number: NCT00469651. Methods This was a double-blind, randomized, controlled, dose escalation phase Ib trial, in which children were given one of two different doses of the MSP3 antigen (15 μg or 30 μg or a control vaccine (Engerix B. Children were randomly allocated either to the MSP3 candidate malaria vaccine or the control vaccine administered at a schedule of 0, 1, and 2 months. Immunization with lower and higher doses was staggered for safety reasons starting with the lower dose. The primary endpoint was safety and reactogenicity within 28 days post-vaccination. Blood samples were obtained at different time points to measure immunological responses. Results are presented up to 84 days post-vaccination. Results A total of 45 children were enrolled, 15 in each of the two MSP3 dose groups and 15 in the Engerix B group. There were no important differences in reactogenicity between the two MSP3 groups and Engerix B. Grade 3 adverse events were infrequent; only five were detected throughout the study, all of which were transient and resolved without sequelae. No serious adverse event reported was considered to be related to MSP3 vaccine. Both MSP3 dose regimens elicited strong cytophilic IgG responses (subclasses IgG1 and IgG3, the isotypes involved in the monocyte-dependant mechanism of Plasmodium falciparum parasite-killing. The titers reached are similar to those from African adults having reached a state of premunition. Furthermore, vaccination induced seroconversion in

  3. NIH Research Leads to Cervical Cancer Vaccine

    Science.gov (United States)

    ... Issues Sexually Transmitted Diseases NIH Research Leads to Cervical Cancer Vaccine Past Issues / Fall 2008 Table of Contents ... in women, the cause of the majority of cervical cancers. Photo courtesy of Judy Folkenberg, NLM Writer By ...

  4. A Large Size Chimeric Highly Immunogenic Peptide Presents Multistage Plasmodium Antigens as a Vaccine Candidate System against Malaria.

    Science.gov (United States)

    Lozano, José Manuel; Varela, Yahson; Silva, Yolanda; Ardila, Karen; Forero, Martha; Guasca, Laura; Guerrero, Yuly; Bermudez, Adriana; Alba, Patricia; Vanegas, Magnolia; Patarroyo, Manuel Elkin

    2017-11-01

    Rational strategies for obtaining malaria vaccine candidates should include not only a proper selection of target antigens for antibody stimulation, but also a versatile molecular design based on ordering the right pieces from the complex pathogen molecular puzzle towards more active and functional immunogens. Classical Plasmodium falciparum antigens regarded as vaccine candidates have been selected as model targets in this study. Among all possibilities we have chosen epitopes of Pf CSP, STARP; MSA1 and Pf 155/RESA from pre- and erythrocyte stages respectively for designing a large 82-residue chimeric immunogen. A number of options aimed at diminishing steric hindrance for synthetic procedures were assessed based on standard Fmoc chemistry such as building block orthogonal ligation; pseudo-proline and microwave-assisted procedures, therefore the large-chimeric target was produced, characterized and immunologically tested. Antigenicity and functional in vivo efficacy tests of the large-chimera formulations administered alone or as antigen mixtures have proven the stimulation of high antibody titers, showing strong correlation with protection and parasite clearance of vaccinated BALB/c mice after being lethally challenged with both P. berghei -ANKA and P. yoelii 17XL malaria strains. Besides, 3D structure features shown by the large-chimera encouraged as to propose using these rational designed large synthetic molecules as reliable vaccine candidate-presenting systems.

  5. A Large Size Chimeric Highly Immunogenic Peptide Presents Multistage Plasmodium Antigens as a Vaccine Candidate System against Malaria

    Directory of Open Access Journals (Sweden)

    José Manuel Lozano

    2017-11-01

    Full Text Available Rational strategies for obtaining malaria vaccine candidates should include not only a proper selection of target antigens for antibody stimulation, but also a versatile molecular design based on ordering the right pieces from the complex pathogen molecular puzzle towards more active and functional immunogens. Classical Plasmodium falciparum antigens regarded as vaccine candidates have been selected as model targets in this study. Among all possibilities we have chosen epitopes of PfCSP, STARP; MSA1 and Pf155/RESA from pre- and erythrocyte stages respectively for designing a large 82-residue chimeric immunogen. A number of options aimed at diminishing steric hindrance for synthetic procedures were assessed based on standard Fmoc chemistry such as building block orthogonal ligation; pseudo-proline and microwave-assisted procedures, therefore the large-chimeric target was produced, characterized and immunologically tested. Antigenicity and functional in vivo efficacy tests of the large-chimera formulations administered alone or as antigen mixtures have proven the stimulation of high antibody titers, showing strong correlation with protection and parasite clearance of vaccinated BALB/c mice after being lethally challenged with both P. berghei-ANKA and P. yoelii 17XL malaria strains. Besides, 3D structure features shown by the large-chimera encouraged as to propose using these rational designed large synthetic molecules as reliable vaccine candidate-presenting systems.

  6. Polymorphism in liver-stage malaria vaccine candidate proteins: immune evasion and implications for vaccine design.

    Science.gov (United States)

    Flanagan, Katie L; Wilson, Kirsty L; Plebanski, Magdalena

    2016-01-01

    The pre-erythrocytic stage of infection by malaria parasites represents a key target for vaccines that aim to eradicate malaria. Two important broad immune evasion strategies that can interfere with vaccine efficacy include the induction of dendritic cell (DC) dysfunction and regulatory T cells (Tregs) by blood-stage malaria parasites, leading to inefficient priming of T cells targeting liver-stage infections. The parasite also uses 'surgical strike' strategies, whereby polymorphism in pre-erythrocytic antigens can interfere with host immunity. Specifically, we review how even single amino acid changes in T cell epitopes can lead to loss of binding to major histocompatibility complex (MHC), lack of cross-reactivity, or antagonism and immune interference, where simultaneous or sequential stimulation with related variants of the same T cell epitope can cause T cell anergy or the conversion of effector to immunosuppressive T cell phenotypes.

  7. Working towards dengue as a vaccine-preventable disease: challenges and opportunities.

    Science.gov (United States)

    Shrivastava, Ambuj; Tripathi, Nagesh K; Dash, Paban K; Parida, Manmohan

    2017-10-01

    Dengue is an emerging viral disease that affects the human population around the globe. Recent advancements in dengue virus research have opened new avenues for the development of vaccines against dengue. The development of a vaccine against dengue is a challenging task because any of the four serotypes of dengue viruses can cause disease. The development of a dengue vaccine aims to provide balanced protection against all the serotypes. Several dengue vaccine candidates are in the developmental stages such as inactivated, live attenuated, recombinant subunit, and plasmid DNA vaccines. Area covered: The authors provide an overview of the progress made in the development of much needed dengue vaccines. The authors include their expert opinion and their perspectives for future developments. Expert opinion: Human trials of a live attenuated tetravalent chimeric vaccine have clearly demonstrated its potential as a dengue vaccine. Other vaccine candidate molecules such as DENVax, a recombinant chimeric vaccine andTetraVax, are at different stages of development at this time. The authors believe that the novel strategies for testing and improving the immune response of vaccine candidates in humans will eventually lead to the development of a successful dengue vaccine in future.

  8. Live, Attenuated Influenza A H5N1 Candidate Vaccines Provide Broad Cross-Protection in Mice and Ferrets

    Science.gov (United States)

    Mills, Kimberly L; Jin, Hong; Duke, Greg; Lu, Bin; Luke, Catherine J; Murphy, Brian; Swayne, David E; Kemble, George; Subbarao, Kanta

    2006-01-01

    Background Recent outbreaks of highly pathogenic influenza A H5N1 viruses in humans and avian species that began in Asia and have spread to other continents underscore an urgent need to develop vaccines that would protect the human population in the event of a pandemic. Methods and Findings Live, attenuated candidate vaccines possessing genes encoding a modified H5 hemagglutinin (HA) and a wild-type (wt) N1 neuraminidase from influenza A H5N1 viruses isolated in Hong Kong and Vietnam in 1997, 2003, and 2004, and remaining gene segments derived from the cold-adapted (ca) influenza A vaccine donor strain, influenza A/Ann Arbor/6/60 ca (H2N2), were generated by reverse genetics. The H5N1 ca vaccine viruses required trypsin for efficient growth in vitro, as predicted by the modification engineered in the gene encoding the HA, and possessed the temperature-sensitive and attenuation phenotypes specified by the internal protein genes of the ca vaccine donor strain. More importantly, the candidate vaccines were immunogenic in mice. Four weeks after receiving a single dose of 106 50% tissue culture infectious doses of intranasally administered vaccines, mice were fully protected from lethality following challenge with homologous and antigenically distinct heterologous wt H5N1 viruses from different genetic sublineages (clades 1, 2, and 3) that were isolated in Asia between 1997 and 2005. Four weeks after receiving two doses of the vaccines, mice and ferrets were fully protected against pulmonary replication of homologous and heterologous wt H5N1 viruses. Conclusions The promising findings in these preclinical studies of safety, immunogenicity, and efficacy of the H5N1 ca vaccines against antigenically diverse H5N1 vaccines provide support for their careful evaluation in Phase 1 clinical trials in humans. PMID:16968127

  9. Live, attenuated influenza A H5N1 candidate vaccines provide broad cross-protection in mice and ferrets.

    Directory of Open Access Journals (Sweden)

    Amorsolo L Suguitan

    2006-09-01

    Full Text Available Recent outbreaks of highly pathogenic influenza A H5N1 viruses in humans and avian species that began in Asia and have spread to other continents underscore an urgent need to develop vaccines that would protect the human population in the event of a pandemic.Live, attenuated candidate vaccines possessing genes encoding a modified H5 hemagglutinin (HA and a wild-type (wt N1 neuraminidase from influenza A H5N1 viruses isolated in Hong Kong and Vietnam in 1997, 2003, and 2004, and remaining gene segments derived from the cold-adapted (ca influenza A vaccine donor strain, influenza A/Ann Arbor/6/60 ca (H2N2, were generated by reverse genetics. The H5N1 ca vaccine viruses required trypsin for efficient growth in vitro, as predicted by the modification engineered in the gene encoding the HA, and possessed the temperature-sensitive and attenuation phenotypes specified by the internal protein genes of the ca vaccine donor strain. More importantly, the candidate vaccines were immunogenic in mice. Four weeks after receiving a single dose of 10(6 50% tissue culture infectious doses of intranasally administered vaccines, mice were fully protected from lethality following challenge with homologous and antigenically distinct heterologous wt H5N1 viruses from different genetic sublineages (clades 1, 2, and 3 that were isolated in Asia between 1997 and 2005. Four weeks after receiving two doses of the vaccines, mice and ferrets were fully protected against pulmonary replication of homologous and heterologous wt H5N1 viruses.The promising findings in these preclinical studies of safety, immunogenicity, and efficacy of the H5N1 ca vaccines against antigenically diverse H5N1 vaccines provide support for their careful evaluation in Phase 1 clinical trials in humans.

  10. Limited antigenic variation in the Trypanosoma cruzi candidate vaccine antigen TSA-1.

    Science.gov (United States)

    Knight, J M; Zingales, B; Bottazzi, M E; Hotez, P; Zhan, B

    2014-12-01

    Chagas disease (American trypanosomiasis caused by Trypanosoma cruzi) is one of the most important neglected tropical diseases in the Western Hemisphere. The toxicities and limited efficacies of current antitrypanosomal drugs have prompted a search for alternative technologies such as a therapeutic vaccine comprised of T. cruzi antigens, including a recombinant antigen encoding the N-terminal 65 kDa portion of Trypomastigote surface antigen-1 (TSA-1). With at least six known genetically distinct T. cruzi lineages, variability between the different lineages poses a unique challenge for the development of broadly effective therapeutic vaccine. The variability across the major lineages in the current vaccine candidate antigen TSA-1 has not previously been addressed. To assess the variation in TSA-1, we cloned and sequenced TSA-1 from several different T. cruzi strains representing three of the most clinically relevant lineages. Analysis of the different alleles showed limited variation in TSA-1 across the different strains and fit with the current theory for the evolution of the different lineages. Additionally, minimal variation in known antigenic epitopes for the HLA-A 02 allele suggests that interlineage variation in TSA-1 would not impair the range and efficacy of a vaccine containing TSA-1. © 2014 John Wiley & Sons Ltd.

  11. Dynamic profiles of neutralizing antibody responses elicited in rhesus monkeys immunized with a combined tetravalent DTaP-Sabin IPV candidate vaccine.

    Science.gov (United States)

    Sun, Mingbo; Ma, Yan; Xu, Yinhua; Yang, Huijuan; Shi, Li; Che, Yanchun; Liao, Guoyang; Jiang, Shude; Zhang, Shumin; Li, Qihan

    2014-02-19

    The World Health Organization has recommended that a Sabin inactivated polio vaccine (IPV) should gradually and synchronously replace oral polio vaccines for routine immunizations because its benefits in eliminating vaccine-associated paralytic poliomyelitis have been reported in different phases of clinical trials. It is also considered important to explore new tetravalent diphtheria, tetanus, and acellular pertussis-Sabin IPV (DTaP-sIPV) candidate vaccines for possible use in developing countries. In this study, the immunogenicity of a combined tetravalent DTaP-sIPV candidate vaccine was investigated in primates by evaluating the neutralizing antibody responses it induced. The dynamic profiles of the antibody responses to each of the separate antigenic components and serotypes of Sabin IPV were determined and their corresponding geometric mean titers were similar to those generated by the tetravalent diphtheria, tetanus, and acellular pertussis-conventional IPV (DTaP-cIPV), the tetravalent diphtheria, tetanus, and acellular pertussis (DTaP), and Sabin IPV vaccines in the control groups. This implies that protective immunogenic effects are conferred by this combined tetravalent formulation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Comparison of the nucleotide sequence of wild-type hepatitis - A virus and its attenuated candidate vaccine derivative

    International Nuclear Information System (INIS)

    Cohen, J.I.; Rosenblum, B.; Ticehurst, J.R.; Daemer, R.; Feinstone, S.; Purcell, R.H.

    1987-01-01

    Development of attenuated mutants for use as vaccines is in progress for other viruses, including influenza, rotavirus, varicella-zoster, cytomegalovirus, and hepatitis-A virus (HAV). Attenuated viruses may be derived from naturally occurring mutants that infect human or nonhuman hosts. Alternatively, attenuated mutants may be generated by passage of wild-type virus in cell culture. Production of attenuated viruses in cell culture is a laborious and empiric process. Despite previous empiric successes, understanding the molecular basis for attenuation of vaccine viruses could facilitate future development and use of live-virus vaccines. Comparison of the complete nucleotide sequences of wild-type (virulent) and vaccine (attenuated) viruses has been reported for polioviruses and yellow fever virus. Here, the authors compare the nucleotide sequence of wild-type HAV HM-175 with that of a candidate vaccine derivative

  13. Candidate mosaic proteins for a pan-filoviral cytotoxic T-Cell lymphocyte vaccine

    Energy Technology Data Exchange (ETDEWEB)

    Fenimore, Paul W [Los Alamos National Laboratory; Fischer, William M [Los Alamos National Laboratory; Kuiken, Carla [Los Alamos National Laboratory; Foley, Brian T [Los Alamos National Laboratory; Thurmond, J R [Los Alamos National Laboratory; Yusim, K [Los Alamos National Laboratory; Korber, B T [Los Alamos National Laboratory

    2008-01-01

    than is possible with a wild-type protein, (2) reducing the number of low-prevalence k-mers minimizes the likelihood of undesirable immunodominance, and (3) excluding exogenous k-mers will result in mosaic proteins whose processing for presentation is close to what occurs with wild-type proteins. The first and second applications of the mosaic method were to HIV and Hepatitis C Virus (HCV). HIV is the virus with the largest number of known sequences, and consequently a plethora of information for the CTL vaccine designer to incorporate into their mosaics. Experience with HIV and HCV mosaics supports the validity of the three conjectures above. The available FILV sequences are probably closer to the minimum amount of information needed to make a meaningful mosaic vaccine candidate. There were 532 protein sequences in the National Institutes of Health GenPept database in November 2007 when our reference set was downloaded. These sequences come from both Ebola and Marburg viruses (EBOV and MARV), representing transcripts of all 7 genes. The coverage of viral diversity by the 7 genes is variable, with genes 1 (nucleoprotein, NP), 4 (glycoprotein, GP; soluble glycoprotein, sGP) and 7 (polymerase, L) giving the best coverage. Broadly-protective vaccine candidates for diverse viruses, such as HIV or Hepatitis C virus (HCV) have required pools of antigens. FILV is similar in this regard. While we have designed CTL mosaic proteins using all 7 types of filoviral proteins, only NP, GP and L proteins are reported here. If it were important to include other proteins in a mosaic CTL vaccine, additional sequences would be required to cover the space of known viral diversity.

  14. Evaluation of a Group A Streptococcus synthetic oligosaccharide as vaccine candidate.

    Science.gov (United States)

    Kabanova, Anna; Margarit, Immaculada; Berti, Francesco; Romano, Maria R; Grandi, Guido; Bensi, Giuliano; Chiarot, Emiliano; Proietti, Daniela; Swennen, Erwin; Cappelletti, Emilia; Fontani, Paola; Casini, Daniele; Adamo, Roberto; Pinto, Vittoria; Skibinski, David; Capo, Sabrina; Buffi, Giada; Gallotta, Marilena; Christ, William J; Campbell, A Stewart; Pena, John; Seeberger, Peter H; Rappuoli, Rino; Costantino, Paolo

    2010-12-10

    Bacterial infections caused by Group A Streptococcus (GAS) are a serious health care concern that currently cannot be prevented by vaccination. The GAS cell-wall polysaccharide (GAS-PS) is an attractive vaccine candidate due to its constant expression pattern on different bacterial strains and protective properties of anti-GAS-PS antibodies. Here we report for the first time the immunoprotective efficacy of glycoconjugates with synthetic GAS oligosaccharides as compared to those containing the native GAS-PS. A series of hexa- and dodecasaccharides based on the GAS-PS structure were prepared by chemical synthesis and conjugated to CRM(197). When tested in mice, the conjugates containing the synthetic oligosaccharides conferred levels of immunoprotection comparable to those elicited by the native conjugate. Antisera from immunized rabbits promoted phagocytosis of encapsulated GAS strains. Furthermore we discuss variables that might correlate with glycoconjugate immunogenicity and demonstrate the potential of the synthetic approach that benefits from increased antigen purity and facilitated manufacturing. Copyright © 2010 Elsevier Ltd. All rights reserved.

  15. Nuclear Magnetic Resonance (NMR Study for the Detection and Quantitation of Cholesterol in HSV529 Therapeutic Vaccine Candidate

    Directory of Open Access Journals (Sweden)

    Rahima Khatun

    Full Text Available This study describes the NMR-based method to determine the limit of quantitation (LOQ and limit of detection (LOD of cholesterol, a process-related impurity in the replication-deficient Herpes Simplex Virus (HSV type 2 candidate vaccine HSV529. Three signature peaks from the 1D 1H NMR of a cholesterol reference spectrum were selected for the identification of cholesterol. The LOQ for a cholesterol working standard was found to be 1 μg/mL, and the LOD was found to be 0.1 μg/mL. The identity of cholesterol, separated from the formulation of growth supplement by thin layer chromatography (TLC, was confirmed by 1D 1H NMR and 2D 1H-13C HSQC NMR. The three signature peaks of cholesterol were detected only in a six-times concentrated sample of HSV529 candidate vaccine sample and not in the single dose HSV529 vaccine sample under similar experimental conditions. Taken together, the results demonstrated that NMR is a direct method that can successfully identify and quantify cholesterol in viral vaccine samples, such as HSV529, and as well as in the growth supplement used during the upstream stages of HSV529 manufacturing. Keywords: Herpes simplex virus type 2 (HSV-2, Viral vaccine, NMR, Residuals, LOD and LOQ, TLC, Growth supplement

  16. Naturally acquired antibody responses to recombinant Pfs230 and Pfs48/45 transmission blocking vaccine candidates

    NARCIS (Netherlands)

    Jones, S; Grignard, L.; Nebie, I.; Chilongola, J.; Dodoo, D.; Sauerwein, R.W.; Theisen, M.; Roeffen, W.F.; Singh, S.K; Singh, R.K.; Kyei-Baafour, E.; Tetteh, K.; Drakeley, C.; Bousema, T.

    2015-01-01

    OBJECTIVES: Pfs48/45 and Pfs230 are Plasmodium falciparum sexual stage proteins and promising malaria transmission-blocking vaccine candidates. Antibody responses against these proteins may be naturally acquired and target antigens may be under selective pressure. This has consequences for the

  17. Collaborative study to assess the suitability of a candidate International Standard for yellow fever vaccine.

    Science.gov (United States)

    Ferguson, Morag; Heath, Alan

    2004-12-01

    Yellow fever vaccines are routinely assayed by plaque assay. However, the results of these assays are then converted into mouse LD(50) using correlations/conversion factors which, in many cases, were established many years ago. The minimum required potency in WHO Recommendations is 10(3) LD(50)/dose. Thirteen participants from 8 countries participated in a collaborative study whose aim was to assess the suitability of two candidate preparations to serve as an International Standard for yellow fever vaccine. In addition, the study investigated the relationship between the mouse LD(50) test and plaque forming units with a view to updating the WHO recommendations. Plaque assays were more reproducible than mouse assays, as expected. Differences in sensitivities of plaque assays were observed between laboratories but these differences appear to be consistent within a laboratory for all samples and the expression of potency relative to the candidate standard vaccine improved the reproducibility of assays between laboratories. However, the use of potencies had little effect on the between laboratory variability in mouse LD(50) assays. There appears to be a consistent relationship between overall mean LD(50) and plaques titre for all study preparations other than sample E. The slope of the correlation curve is >1 and it would appear that 10(3) LD(50) is approximately equivalent to 10(4) plaque forming units (PFU), based on the overall means of all laboratory results. The First International Standard for yellow fever vaccine, NIBSC Code 99/616, has been established as the First International Standard for yellow fever vaccine by the Expert Committee of Biological Standards of the World Health Organisation. The International Standard has been arbitrarily assigned a potency of 10(4.5) International Units (IU) per ampoule. Manufacturers and National Control Laboratories are including the First International Standard for yellow fever vaccine in routine assays so that the minimum

  18. A plant-produced Pfs230 vaccine candidate blocks transmission of Plasmodium falciparum.

    Science.gov (United States)

    Farrance, Christine E; Rhee, Amy; Jones, R Mark; Musiychuk, Konstantin; Shamloul, Moneim; Sharma, Satish; Mett, Vadim; Chichester, Jessica A; Streatfield, Stephen J; Roeffen, Will; van de Vegte-Bolmer, Marga; Sauerwein, Robert W; Tsuboi, Takafumi; Muratova, Olga V; Wu, Yimin; Yusibov, Vidadi

    2011-08-01

    Plasmodium falciparum is transmitted to a new host after completing its sexual cycle within a mosquito. Developing vaccines against the parasite sexual stages is a critical component in the fight against malaria. We are targeting multiple proteins of P. falciparum which are found only on the surfaces of the sexual forms of the parasite and where antibodies against these proteins have been shown to block the progression of the parasite's life cycle in the mosquito and thus block transmission to the next human host. We have successfully produced a region of the Pfs230 antigen in our plant-based transient-expression system and evaluated this vaccine candidate in an animal model. This plant-produced protein, 230CMB, is expressed at approximately 800 mg/kg in fresh whole leaf tissue and is 100% soluble. Administration of 230CMB with >90% purity induces strong immune responses in rabbits with high titers of transmission-blocking antibodies, resulting in a greater than 99% reduction in oocyst counts in the presence of complement, as determined by a standard membrane feeding assay. Our data provide a clear perspective on the clinical development of a Pfs230-based transmission-blocking malaria vaccine.

  19. Bioinformatics analysis of Brucella vaccines and vaccine targets using VIOLIN.

    Science.gov (United States)

    He, Yongqun; Xiang, Zuoshuang

    2010-09-27

    Brucella spp. are Gram-negative, facultative intracellular bacteria that cause brucellosis, one of the commonest zoonotic diseases found worldwide in humans and a variety of animal species. While several animal vaccines are available, there is no effective and safe vaccine for prevention of brucellosis in humans. VIOLIN (http://www.violinet.org) is a web-based vaccine database and analysis system that curates, stores, and analyzes published data of commercialized vaccines, and vaccines in clinical trials or in research. VIOLIN contains information for 454 vaccines or vaccine candidates for 73 pathogens. VIOLIN also contains many bioinformatics tools for vaccine data analysis, data integration, and vaccine target prediction. To demonstrate the applicability of VIOLIN for vaccine research, VIOLIN was used for bioinformatics analysis of existing Brucella vaccines and prediction of new Brucella vaccine targets. VIOLIN contains many literature mining programs (e.g., Vaxmesh) that provide in-depth analysis of Brucella vaccine literature. As a result of manual literature curation, VIOLIN contains information for 38 Brucella vaccines or vaccine candidates, 14 protective Brucella antigens, and 68 host response studies to Brucella vaccines from 97 peer-reviewed articles. These Brucella vaccines are classified in the Vaccine Ontology (VO) system and used for different ontological applications. The web-based VIOLIN vaccine target prediction program Vaxign was used to predict new Brucella vaccine targets. Vaxign identified 14 outer membrane proteins that are conserved in six virulent strains from B. abortus, B. melitensis, and B. suis that are pathogenic in humans. Of the 14 membrane proteins, two proteins (Omp2b and Omp31-1) are not present in B. ovis, a Brucella species that is not pathogenic in humans. Brucella vaccine data stored in VIOLIN were compared and analyzed using the VIOLIN query system. Bioinformatics curation and ontological representation of Brucella vaccines

  20. Comparative genomics study for the identification of drug and vaccine targets in Staphylococcus aureus: MurA ligase enzyme as a proposed candidate.

    Science.gov (United States)

    Ghosh, Soma; Prava, Jyoti; Samal, Himanshu Bhusan; Suar, Mrutyunjay; Mahapatra, Rajani Kanta

    2014-06-01

    Now-a-days increasing emergence of antibiotic-resistant pathogenic microorganisms is one of the biggest challenges for management of disease. In the present study comparative genomics, metabolic pathways analysis and additional parameters were defined for the identification of 94 non-homologous essential proteins in Staphylococcus aureus genome. Further study prioritized 19 proteins as vaccine candidates where as druggability study reports 34 proteins suitable as drug targets. Enzymes from peptidoglycan biosynthesis, folate biosynthesis were identified as candidates for drug development. Furthermore, bacterial secretory proteins and few hypothetical proteins identified in our analysis fulfill the criteria of vaccine candidates. As a case study, we built a homology model of one of the potential drug target, MurA ligase, using MODELLER (9v12) software. The model has been further selected for in silico docking study with inhibitors from the DrugBank database. Results from this study could facilitate selection of proteins for entry into drug design and vaccine production pipelines. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Replacement of the Ectodomains of the Hemagglutinin-Neuraminidase and Fusion Glycoproteins of Recombinant Parainfluenza Virus Type 3 (PIV3) with Their Counterparts from PIV2 Yields Attenuated PIV2 Vaccine Candidates

    OpenAIRE

    Tao, Tao; Skiadopoulos, Mario H.; Davoodi, Fatemeh; Riggs, Jeffrey M.; Collins, Peter L.; Murphy, Brian R.

    2000-01-01

    We sought to develop a live attenuated parainfluenza virus type 2 (PIV2) vaccine strain for use in infants and young children, using reverse genetic techniques that previously were used to rapidly produce a live attenuated PIV1 vaccine candidate. The PIV1 vaccine candidate, designated rPIV3-1cp45, was generated by substituting the full-length HN and F proteins of PIV1 for those of PIV3 in the attenuated cp45 PIV3 vaccine candidate (T. Tao et al., J. Virol. 72:2955–2961, 1998; M. H. Skiadopoul...

  2. [Overview of the Ebola vaccines in pre-clinical and clinical development].

    Science.gov (United States)

    Buchy, P

    2016-10-01

    The Ebola epidemic that occurred in West Africa between 2013-2016 significantly accelerated the research and development of Ebola vaccines. Few dozens of clinical trials have been recently conducted leading to opportunities to test several new vaccine candidates. Other vaccines are still in early development phases (table 1). This paper provides an overview of the new developments in that area.

  3. Top Down Tandem Mass Spectrometric Analysis of a Chemically Modified Rough-Type Lipopolysaccharide Vaccine Candidate

    Science.gov (United States)

    Oyler, Benjamin L.; Khan, Mohd M.; Smith, Donald F.; Harberts, Erin M.; Kilgour, David P. A.; Ernst, Robert K.; Cross, Alan S.; Goodlett, David R.

    2018-02-01

    Recent advances in lipopolysaccharide (LPS) biology have led to its use in drug discovery pipelines, including vaccine and vaccine adjuvant discovery. Desirable characteristics for LPS vaccine candidates include both the ability to produce a specific antibody titer in patients and a minimal host inflammatory response directed by the innate immune system. However, in-depth chemical characterization of most LPS extracts has not been performed; hence, biological activities of these extracts are unpredictable. Additionally, the most widely adopted workflow for LPS structure elucidation includes nonspecific chemical decomposition steps before analyses, making structures inferred and not necessarily biologically relevant. In this work, several different mass spectrometry workflows that have not been previously explored were employed to show proof-of-principle for top down LPS primary structure elucidation, specifically for a rough-type mutant (J5) E. coli-derived LPS component of a vaccine candidate. First, ion mobility filtered precursor ions were subjected to collision induced dissociation (CID) to define differences in native J5 LPS v. chemically detoxified J5 LPS (dLPS). Next, ultra-high mass resolving power, accurate mass spectrometry was employed for unequivocal precursor and product ion empirical formulae generation. Finally, MS3 analyses in an ion trap instrument showed that previous knowledge about dissociation of LPS components can be used to reconstruct and sequence LPS in a top down fashion. A structural rationale is also explained for differential inflammatory dose-response curves, in vitro, when HEK-Blue hTLR4 cells were administered increasing concentrations of native J5 LPS v. dLPS, which will be useful in future drug discovery efforts. [Figure not available: see fulltext.

  4. The meningococcal vaccine candidate neisserial surface protein A (NspA binds to factor H and enhances meningococcal resistance to complement.

    Directory of Open Access Journals (Sweden)

    Lisa A Lewis

    2010-07-01

    Full Text Available Complement forms an important arm of innate immunity against invasive meningococcal infections. Binding of the alternative complement pathway inhibitor factor H (fH to fH-binding protein (fHbp is one mechanism meningococci employ to limit complement activation on the bacterial surface. fHbp is a leading vaccine candidate against group B Neisseria meningitidis. Novel mechanisms that meningococci employ to bind fH could undermine the efficacy of fHbp-based vaccines. We observed that fHbp deletion mutants of some meningococcal strains showed residual fH binding suggesting the presence of a second receptor for fH. Ligand overlay immunoblotting using membrane fractions from one such strain showed that fH bound to a approximately 17 kD protein, identified by MALDI-TOF analysis as Neisserial surface protein A (NspA, a meningococcal vaccine candidate whose function has not been defined. Deleting nspA, in the background of fHbp deletion mutants, abrogated fH binding and mAbs against NspA blocked fH binding, confirming NspA as a fH binding molecule on intact bacteria. NspA expression levels vary among strains and expression correlated with the level of fH binding; over-expressing NspA enhanced fH binding to bacteria. Progressive truncation of the heptose (Hep I chain of lipooligosaccharide (LOS, or sialylation of lacto-N-neotetraose LOS both increased fH binding to NspA-expressing meningococci, while expression of capsule reduced fH binding to the strains tested. Similar to fHbp, binding of NspA to fH was human-specific and occurred through fH domains 6-7. Consistent with its ability to bind fH, deleting NspA increased C3 deposition and resulted in increased complement-dependent killing. Collectively, these data identify a key complement evasion mechanism with important implications for ongoing efforts to develop meningococcal vaccines that employ fHbp as one of its components.

  5. Conjugating recombinant proteins to Pseudomonas aeruginosa ExoProtein A: a strategy for enhancing immunogenicity of malaria vaccine candidates.

    Science.gov (United States)

    Qian, Feng; Wu, Yimin; Muratova, Olga; Zhou, Hong; Dobrescu, Gelu; Duggan, Peter; Lynn, Lambert; Song, Guanhong; Zhang, Yanling; Reiter, Karine; MacDonald, Nicholas; Narum, David L; Long, Carole A; Miller, Louis H; Saul, Allan; Mullen, Gregory E D

    2007-05-16

    Conjugation of polysaccharides to carrier proteins has been a successful approach for producing safe and effective vaccines. In an attempt to increase the immunogenicity of two malarial vaccine candidate proteins of Plasmodium falciparum, apical membrane antigen 1 (AMA1) to a blood stage vaccine candidate and surface protein 25 (Pfs25) a mosquito stage vaccine candidate, were each independently chemically conjugated to the mutant, nontoxic Pseudomonas aeruginosa ExoProtein A (rEPA). AMA1 is a large (66kD) relatively good immunogen in mice; Pfs25 is a poorly immunogenic protein when presented on alum to mice. Mice were immunized on days 0 and 28 with AMA1- or Pfs25-rEPA conjugates or unconjugated AMA1 or Pfs25, all formulated on Alhydrogel. Remarkably, sera from mice 14 days after the second immunization with Pfs25-rEPA conjugates displayed over a 1000-fold higher antibody titers as compared to unconjugated Pfs25. In contrast, AMA1 conjugated under the same conditions induced only a three-fold increase in antibody titers. When tested for functional activity, antibodies elicited by the AMA1-rEPA inhibited invasion of erythrocytes by blood-stage parasites and antibodies elicited by the Pfs25-rEPA conjugates blocked the development of the sexual stage parasites in the mosquito midgut. These results demonstrate that conjugation to rEPA induces a marked improvement in the antibody titer in mice for the poor immunogen (Pfs25) and for the larger protein (AMA1). These conjugates now need to be tested in humans to determine if mice are predictive of the response in humans.

  6. Phase 1/2a Trial of Plasmodium vivax Malaria Vaccine Candidate VMP001/AS01B in Malaria-Naive Adults: Safety, Immunogenicity, and Efficacy.

    Directory of Open Access Journals (Sweden)

    Jason W Bennett

    2016-02-01

    Full Text Available A vaccine to prevent infection and disease caused by Plasmodium vivax is needed both to reduce the morbidity caused by this parasite and as a key component in efforts to eradicate malaria worldwide. Vivax malaria protein 1 (VMP001, a novel chimeric protein that incorporates the amino- and carboxy- terminal regions of the circumsporozoite protein (CSP and a truncated repeat region that contains repeat sequences from both the VK210 (type 1 and the VK247 (type 2 parasites, was developed as a vaccine candidate for global use.We conducted a first-in-human Phase 1 dose escalation vaccine study with controlled human malaria infection (CHMI of VMP001 formulated in the GSK Adjuvant System AS01B. A total of 30 volunteers divided into 3 groups (10 per group were given 3 intramuscular injections of 15 μg, 30 μg, or 60 μg respectively of VMP001, all formulated in 500 μL of AS01B at each immunization. All vaccinated volunteers participated in a P. vivax CHMI 14 days following the third immunization. Six non-vaccinated subjects served as infectivity controls.The vaccine was shown to be well tolerated and immunogenic. All volunteers generated robust humoral and cellular immune responses to the vaccine antigen. Vaccination did not induce sterile protection; however, a small but significant delay in time to parasitemia was seen in 59% of vaccinated subjects compared to the control group. An association was identified between levels of anti-type 1 repeat antibodies and prepatent period.This trial was the first to assess the efficacy of a P. vivax CSP vaccine candidate by CHMI. The association of type 1 repeat-specific antibody responses with delay in the prepatency period suggests that augmenting the immune responses to this domain may improve strain-specific vaccine efficacy. The availability of a P. vivax CHMI model will accelerate the process of P. vivax vaccine development, allowing better selection of candidate vaccines for advancement to field trials.

  7. An Investigation of Immunogenicity of Chitosan-Based Botulinum Neurotoxin E Binding Domain Recombinant Candidate Vaccine via Mucosal Route

    Directory of Open Access Journals (Sweden)

    Mohammad Javad Bagheripour

    2017-01-01

    Full Text Available Background and Objectives: Botulism syndrome is caused by serotypes A-G of neurotoxins of Clostridium genus. Neurotoxin binding domain is an appropriate vaccine candidate due to its immunogenic activity. In this study, the immunogenicity of chitosan-based botulinum neurotoxin E binding domain recombinant candidate vaccine was investigated via mucosal route of administration. Methods: In this experimental study, chitosan nanoparticles containing rBoNT/E protein were synthesized by ionic gelation method and were administered orally and intranasally to mice. After each administration, IgG antibody titer was measured by ELISA method. Finally, all groups were challenged with active botulinum neurotoxin type E. Data were analyzed using Duncan and repeated ANOVA tests. The significance level was considered as p0.05, even intranasal route reduced the immunogenicity.

  8. The Human Hookworm Vaccine.

    Science.gov (United States)

    Hotez, Peter J; Diemert, David; Bacon, Kristina M; Beaumier, Coreen; Bethony, Jeffrey M; Bottazzi, Maria Elena; Brooker, Simon; Couto, Artur Roberto; Freire, Marcos da Silva; Homma, Akira; Lee, Bruce Y; Loukas, Alex; Loblack, Marva; Morel, Carlos Medicis; Oliveira, Rodrigo Correa; Russell, Philip K

    2013-04-18

    Hookworm infection is one of the world's most common neglected tropical diseases and a leading cause of iron deficiency anemia in low- and middle-income countries. A Human Hookworm Vaccine is currently being developed by the Sabin Vaccine Institute and is in phase 1 clinical testing. The candidate vaccine is comprised of two recombinant antigens known as Na-GST-1 and Na-APR-1, each of which is an important parasite enzyme required for hookworms to successfully utilize host blood as a source of energy. The recombinant proteins are formulated on Alhydrogel(®) and are being tested in combination with a synthetic Toll-like receptor 4 agonist. The aim of the vaccine is to induce anti-enzyme antibodies that will reduce both host blood loss and the number of hookworms attached to the gut. Transfer of the manufacturing technology to the Oswaldo Cruz Foundation (FIOCRUZ)/Bio-Manguinhos (a Brazilian public sector developing country vaccine manufacturer) is planned, with a clinical development plan that could lead to registration of the vaccine in Brazil. The vaccine would also need to be introduced in the poorest regions of Africa and Asia, where hookworm infection is highly endemic. Ultimately, the vaccine could become an essential tool for achieving hookworm control and elimination, a key target in the 2012 London Declaration on Neglected Tropical Diseases. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Characterization of Brucella abortus mutant strain Δ22915, a potential vaccine candidate.

    Science.gov (United States)

    Bao, Yanqing; Tian, Mingxing; Li, Peng; Liu, Jiameng; Ding, Chan; Yu, Shengqing

    2017-04-04

    Brucellosis, caused by Brucella spp., is an important zoonosis worldwide. Vaccination is an effective strategy for protection against Brucella infection in livestock in developing countries and in wildlife in developed countries. However, current vaccine strains including S19 and RB51 are pathogenic to humans and pregnant animals, limiting their use. In this study, we constructed the Brucella abortus (B. abortus) S2308 mutant strain Δ22915, in which the putative lytic transglycosylase gene BAB_RS22915 was deleted. The biological properties of mutant strain Δ22915 were characterized and protection of mice against virulent S2308 challenge was evaluated. The mutant strain Δ22915 showed reduced survival within RAW264.7 cells and survival in vivo in mice. In addition, the mutant strain Δ22915 failed to escape fusion with lysosomes within host cells, and caused no observable pathological damage. RNA-seq analysis indicated that four genes associated with amino acid/nucleotide transport and metabolism were significantly upregulated in mutant strain Δ22915. Furthermore, inoculation of ∆22915 at 10 5 colony forming units induced effective host immune responses and long-term protection of BALB/c mice. Therefore, mutant strain ∆22915 could be used as a novel vaccine candidate in the future to protect animals against B. abortus infection.

  10. Generation of transgenic corn-derived Actinobacillus pleuropneumoniae ApxIIA fused with the cholera toxin B subunit as a vaccine candidate

    Science.gov (United States)

    Shin, Min-Kyoung; Jung, Myung Hwan; Lee, Won-Jung; Choi, Pil Son; Jang, Yong-Suk

    2011-01-01

    Corn, one of the most important forage crops worldwide, has proven to be a useful expression vehicle due to the availability of established transformation procedures for this well-studied plant. The exotoxin Apx, a major virulence factor, is recognized as a common antigen of Actinobacillus (A.) pleuropneumoniae, the causative agent of porcine pleuropneumonia. In this study, a cholera toxin B (CTB)-ApxIIA#5 fusion protein and full-size ApxIIA expressed in corn seed, as a subunit vaccine candidate, were observed to induce Apx-specific immune responses in mice. These results suggest that transgenic corn-derived ApxIIA and CTB-ApxIIA#5 proteins are potential vaccine candidates against A. pleuropneumoniae infection. PMID:22122907

  11. Advances in the development of vaccines for dengue fever

    Directory of Open Access Journals (Sweden)

    Simmons M

    2012-05-01

    Full Text Available Monika Simmons1, Nimfa Teneza-Mora1, Robert Putnak21Viral and Rickettsial Diseases Department, Naval Medical Research Center, 2Division of Viral Diseases, Walter Reed Army Institute of Research, Silver Spring, MD, USAAbstract: Dengue fever is caused by the mosquito-borne dengue virus (DENV serotypes 1–4, and is the most common arboviral infection of humans in subtropical and tropical regions of the world. There are currently no prophylaxis or treatment options in the form of vaccines or antivirals, leaving vector control the only method of prevention. A particular challenge with DENV is that a successful vaccine has to be effective against all four serotypes without predisposing for antibody-mediated enhanced disease. In this review, we discuss the current lead vaccine candidates in clinical trials, as well as some second-generation vaccine candidates undergoing preclinical evaluation. In addition, we discuss DENV epidemiology, clinical disease and strategies used for Flavivirus antivirals in the past, the development of new DENV therapeutics, and their potential usefulness for prophylaxis and treatment.Keywords: tetravalent dengue vaccine, live attenuated vaccine, purified inactivated vaccine, DNA vaccine, antibody-dependent enhancement, antivirals

  12. HIV-1 Immunogen: an overview of almost 30 years of clinical testing of a candidate therapeutic vaccine.

    Science.gov (United States)

    Graziani, Gina M; Angel, Jonathan B

    2016-07-01

    Although current antiretroviral therapy (ART) has transformed HIV infection into a chronic, manageable disease, ART does not cure HIV infection. Furthermore, the majority of the world's infected individuals live in resource-limited countries in which access to ART is limited. Thus, the development of an effective therapeutic HIV vaccine would be an invaluable treatment alternative. Developed by the late Dr. Jonas Salk, HIV-1 Immunogen (Remune®) is a candidate therapeutic vaccine that has been studied in thousands of HIV-infected individuals in more than a dozen clinical trials during almost three decades. This Drug Evaluation, which summarizes the results of these trials that have shown the vaccine to be safe and immunogenic, also discusses the contradictory and controversial conclusions drawn from the phases 2, 2/3 and 3 trials that assessed the clinical efficacy of this vaccine. Given the lack of unequivocal clinical benefits of HIV-1 Immunogen despite almost 30 years of extensive testing, it does not appear, in our view, that this vaccine is a clinically effective immunotherapy. However, inclusion of this vaccine in the newly proposed 'Kick/Shock and Kill' strategy for HIV eradication, or use as a prophylactic vaccine, could be considered for future trials.

  13. Phase 1 trial of malaria transmission blocking vaccine candidates Pfs25 and Pvs25 formulated with montanide ISA 51.

    Directory of Open Access Journals (Sweden)

    Yimin Wu

    2008-07-01

    Full Text Available Pfs25 and Pvs25, surface proteins of mosquito stage of the malaria parasites P. falciparum and P. vivax, respectively, are leading candidates for vaccines preventing malaria transmission by mosquitoes. This single blinded, dose escalating, controlled Phase 1 study assessed the safety and immunogenicity of recombinant Pfs25 and Pvs25 formulated with Montanide ISA 51, a water-in-oil emulsion.The trial was conducted at The Johns Hopkins Center for Immunization Research, Washington DC, USA, between May 16, 2005-April 30, 2007. The trial was designed to enroll 72 healthy male and non-pregnant female volunteers into 1 group to receive adjuvant control and 6 groups to receive escalating doses of the vaccines. Due to unexpected reactogenicity, the vaccination was halted and only 36 volunteers were enrolled into 4 groups: 3 groups of 10 volunteers each were immunized with 5 microg of Pfs25/ISA 51, 5 microg of Pvs25/ISA 51, or 20 microg of Pvs25/ISA 51, respectively. A fourth group of 6 volunteers received adjuvant control (PBS/ISA 51. Frequent local reactogenicity was observed. Systemic adverse events included two cases of erythema nodosum considered to be probably related to the combination of the antigen and the adjuvant. Significant antibody responses were detected in volunteers who completed the lowest scheduled doses of Pfs25/ISA 51. Serum anti-Pfs25 levels correlated with transmission blocking activity.It is feasible to induce transmission blocking immunity in humans using the Pfs25/ISA 51 vaccine, but these vaccines are unexpectedly reactogenic for further development. This is the first report that the formulation is associated with systemic adverse events including erythema nodosum.ClinicalTrials.gov NCT00295581.

  14. Points for Consideration for dengue vaccine introduction - recommendations by the Dengue Vaccine Initiative.

    Science.gov (United States)

    Lim, Jacqueline Kyungah; Lee, Yong-Seok; Wilder-Smith, Annelies; Thiry, Georges; Mahoney, Richard; Yoon, In-Kyu

    2016-01-01

    Dengue is a public health problem in the tropics and subtropics. There are several vaccine candidates in clinical development. However, there may be gaps in the new vaccine introduction after vaccine licensure before it becomes available in developing countries. In anticipation of the first dengue vaccine candidate to be licensed, Dengue Vaccine Initiative (DVI) and, its predecessor, Pediatric Dengue Vaccine Initiative (PDVI) have been working on points for consideration to accelerate evidence-based dengue vaccine introduction, once a vaccine becomes available. In this paper, we review the history of PDVI and its successor, the DVI, and elaborate on the points of consideration for dengue vaccine introduction.

  15. Safety of the malaria vaccine candidate, RTS,S/AS01E in 5 to 17 month old Kenyan and Tanzanian Children.

    Directory of Open Access Journals (Sweden)

    John Lusingu

    2010-11-01

    Full Text Available The malaria vaccine candidate, RTS,S/AS01(E, showed promising protective efficacy in a trial of Kenyan and Tanzanian children aged 5 to 17 months. Here we report on the vaccine's safety and tolerability. The experimental design was a Phase 2b, two-centre, double-blind (observer- and participant-blind, randomised (1∶1 ratio controlled trial. Three doses of study or control (rabies vaccines were administered intramuscularly at 1 month intervals. Solicited adverse events (AEs were collected for 7 days after each vaccination. There was surveillance and reporting for unsolicited adverse events for 30 days after each vaccination. Serious adverse events (SAEs were recorded throughout the study period which lasted for 14 months after dose 1 in Korogwe, Tanzania and an average of 18 months post-dose 1 in Kilifi, Kenya. Blood samples for safety monitoring of haematological, renal and hepatic functions were taken at baseline, 3, 10 and 14 months after dose 1. A total of 894 children received RTS,S/AS01(E or rabies vaccine between March and August 2007. Overall, children vaccinated with RTS,S/AS01(E had fewer SAEs (51/447 than children in the control group (88/447. One SAE episode in a RTS,S/AS01(E recipient and nine episodes among eight rabies vaccine recipients met the criteria for severe malaria. Unsolicited AEs were reported in 78% of subjects in the RTS,S/AS01(E group and 74% of subjects in the rabies vaccine group. In both vaccine groups, gastroenteritis and pneumonia were the most frequently reported unsolicited AE. Fever was the most frequently observed solicited AE and was recorded after 11% of RTS,S/AS01(E doses compared to 31% of doses of rabies vaccine. The candidate vaccine RTS,S/AS01(E showed an acceptable safety profile in children living in a malaria-endemic area in East Africa. More data on the safety of RTS,S/AS01(E will become available from the Phase 3 programme.

  16. Leishmaniasis vaccine candidates for development: a global overview.

    Science.gov (United States)

    Khamesipour, Ali; Rafati, Sima; Davoudi, Noushin; Maboudi, Fereidoun; Modabber, Farrokh

    2006-03-01

    A vaccine against different forms of leishmaniasis should be feasible considering the wealth of information on genetics and biology of the parasite, clinical and experimental immunology of leishmaniasis, and the availability of vaccines that can protect experimental animals against challenge with different Leishmania species. However, there is no vaccine against any form of leishmaniasis for general human use. One major factor is the lack of a conceived market for human leishmaniasis vaccines. Hence pharmaceutical industries involved in vaccine development are not interested in investing millions of dollars and a decade that is required for developing a new vaccine. Besides, leishmaniasis is a local/regional problem and not a global one. According to the estimates of the World Health Organization, 90 per cent of visceral leishmaniasis occurs in five countries (Bangladesh, Brazil, India, Nepal and Sudan). Those in need are amongst the poorest people in these countries. It should therefore be the objectives of these countries to develop a vaccine. Fortunately, both Brazil and India have designated the control of visceral leishmaniasis as a top priority for their respective Ministries of Health. The purpose of this review is to present only the vaccines in use and those in development for use in dogs or humans. This is not an exhaustive review of vaccine discovery or the principles of clinical immunology underlying vaccine development.

  17. Structure and interactions of a malarial vaccine candidate, AMA1, form the parasite plasmodium falciparum

    International Nuclear Information System (INIS)

    Miles, L.A.; Keizer, D.W.; Hodder, A.N.; Nair, M.; Hinds, M.G.; Norton, R.S.; Li, F.; Foley, M.; Coley, A.; Anders, R.F.

    2001-01-01

    Full text: Apical membrane antigen 1 (AMA1), a merozoite surface protein found in all species of Plasmodium and other apicomplexan parasites, is a strong candidate for inclusion in a malarial vaccine. Recombinant AMA1 protected against P. fragile in monkeys and P. chabaudi adami in mice. P. falciparum AMA1 which has a 62-kDa ectodomain consisting of three disulphide-stabilised domains, is a target of antibodies that inhibit merozoite invasion in vitro. Here we describe the solution structure of domain III (14 kDa), determined by NMR on 15 N- and 13 C/ 15 N-labelled samples. It has a well-defined disulphide-stabilised core interrupted by a disordered loop, and both the N- and C-terminal regions of the molecule are unstructured. The structured region includes all three disulphide bonds. Naturally-occurring mutations across 11 different P falciparum strains that are located far apart in the sequence cluster around the disulphide core in the 3D structure of domain III, suggesting that this region contains the major epitopes recognised by neutralising antibodies. Consistent with this, the disulphide-bond stabilised conformation of the ectodomain was essential for protection, as the antigen was not an effective vaccine after reduction and alkylation. Peptides have been found by phage display that bind to AMA1 and block merozoite invasion of erythrocytes. We have investigated their solution structures and interaction with full-length AMA1 ectodomain in an effort to understand the structure-function relationships of this important vaccine candidate

  18. Effect of vaccine dose on the safety and immunogenicity of a candidate TB vaccine, MVA85A, in BCG vaccinated UK adults.

    Science.gov (United States)

    Pathan, Ansar A; Minassian, Angela M; Sander, Clare R; Rowland, Rosalind; Porter, David W; Poulton, Ian D; Hill, Adrian V S; Fletcher, Helen A; McShane, Helen

    2012-08-17

    A non-randomised, open-label, Phase I safety and immunogenicity dose-finding study to assess the safety and immunogenicity of the candidate TB vaccine Modified Vaccinia virus Ankara expressing Antigen 85A (MVA85A) from Mycobacterium tuberculosis (MTB) in healthy adult volunteers previously vaccinated with BCG. Healthy BCG-vaccinated volunteers were vaccinated with either 1×10(7) or 1×10(8)PFU of MVA85A. All adverse events were documented and antigen specific T cell responses were measured using an ex vivo IFN-γ ELISPOT assay. Safety and immunogenicity were compared between the 2 dose groups and with a previous trial in which a dose of 5×10(7)PFU MVA85A had been administered. There were no serious adverse events recorded following administration of either 1×10(7) or 1×10(8)PFU of MVA85A. Systemic adverse events were more frequently reported following administration of 1×10(8)PFU of MVA85A when compared to either 5×10(7) or 1×10(7)PFU of MVA85A but were mild or moderate in severity and resolved completely within 7 days of immunisation. Antigen specific T cell responses as measured by the IFN-γ ELISPOT were significantly higher following immunisation in adults receiving 1×10(8)PFU compared to the 5×10(7) and 1×10(7) doses. Additionally, a broader range of Ag85A epitopes are detected following 1×10(8)PFU of MVA85A. A higher dose of 1×10(8)PFU of MVA85A is well-tolerated, increases the frequency of IFN-γ secreting T cells detected following immunisation and broadens the range of Ag85A epitopes detected. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Optimization of HIV-1 Envelope DNA Vaccine Candidates within Three Different Animal Models, Guinea Pigs, Rabbits and Cynomolgus Macaques.

    Science.gov (United States)

    Borggren, Marie; Vinner, Lasse; Andresen, Betina Skovgaard; Grevstad, Berit; Repits, Johanna; Melchers, Mark; Elvang, Tara Laura; Sanders, Rogier W; Martinon, Frédéric; Dereuddre-Bosquet, Nathalie; Bowles, Emma Joanne; Stewart-Jones, Guillaume; Biswas, Priscilla; Scarlatti, Gabriella; Jansson, Marianne; Heyndrickx, Leo; Grand, Roger Le; Fomsgaard, Anders

    2013-07-19

    HIV-1 DNA vaccines have many advantageous features. Evaluation of HIV-1 vaccine candidates often starts in small animal models before macaque and human trials. Here, we selected and optimized DNA vaccine candidates through systematic testing in rabbits for the induction of broadly neutralizing antibodies (bNAb). We compared three different animal models: guinea pigs, rabbits and cynomolgus macaques. Envelope genes from the prototype isolate HIV-1 Bx08 and two elite neutralizers were included. Codon-optimized genes, encoded secreted gp140 or membrane bound gp150, were modified for expression of stabilized soluble trimer gene products, and delivered individually or mixed. Specific IgG after repeated i.d. inoculations with electroporation confirmed in vivo expression and immunogenicity. Evaluations of rabbits and guinea pigs displayed similar results. The superior DNA construct in rabbits was a trivalent mix of non-modified codon-optimized gp140 envelope genes. Despite NAb responses with some potency and breadth in guinea pigs and rabbits, the DNA vaccinated macaques displayed less bNAb activity. It was concluded that a trivalent mix of non-modified gp140 genes from rationally selected clinical isolates was, in this study, the best option to induce high and broad NAb in the rabbit model, but this optimization does not directly translate into similar responses in cynomolgus macaques.

  20. Optimization of HIV-1 Envelope DNA Vaccine Candidates within Three Different Animal Models, Guinea Pigs, Rabbits and Cynomolgus Macaques

    Directory of Open Access Journals (Sweden)

    Roger Le Grand

    2013-07-01

    Full Text Available HIV-1 DNA vaccines have many advantageous features. Evaluation of HIV-1 vaccine candidates often starts in small animal models before macaque and human trials. Here, we selected and optimized DNA vaccine candidates through systematic testing in rabbits for the induction of broadly neutralizing antibodies (bNAb. We compared three different animal models: guinea pigs, rabbits and cynomolgus macaques. Envelope genes from the prototype isolate HIV-1 Bx08 and two elite neutralizers were included. Codon-optimized genes, encoded secreted gp140 or membrane bound gp150, were modified for expression of stabilized soluble trimer gene products, and delivered individually or mixed. Specific IgG after repeated i.d. inoculations with electroporation confirmed in vivo expression and immunogenicity. Evaluations of rabbits and guinea pigs displayed similar results. The superior DNA construct in rabbits was a trivalent mix of non-modified codon-optimized gp140 envelope genes. Despite NAb responses with some potency and breadth in guinea pigs and rabbits, the DNA vaccinated macaques displayed less bNAb activity. It was concluded that a trivalent mix of non-modified gp140 genes from rationally selected clinical isolates was, in this study, the best option to induce high and broad NAb in the rabbit model, but this optimization does not directly translate into similar responses in cynomolgus macaques.

  1. Cellular and humoral immune responses in sheep vaccinated with candidate antigens MAP2698c and MAP3567 from Mycobacterium avium subspecies paratuberculosis

    Science.gov (United States)

    Gurung, Ratna B.; Purdie, Auriol C.; Whittington, Richard J.; Begg, Douglas J.

    2014-01-01

    Control of Johne's disease, caused by Mycobacterium avium subspecies paratuberculosis (MAP) in ruminants using commercially available vaccine reduces production losses, mortality, fecal shedding and histopathological lesions but does not provide complete protection from infection and interferes with serological diagnosis of Johne's disease and bovine tuberculosis. At this time no recombinant antigens have been found to provide superior protection compared to whole killed or live-attenuated MAP vaccines. Therefore, there is a need to evaluate more candidate MAP antigens. In this study recombinant MAP antigens MAP2698c and MAP3567 were formulated with four different MONTANIDE™ (ISA 50V2, 61VG, 71VG, and 201VG) adjuvants and evaluated for their ability to produce specific immune responses in vaccinated sheep. The cellular immune response was measured with an interferon-gamma (IFN-γ) release assay and the humoral immune response was measured by antibody detection enzyme linked immunosorbent assay. Recombinant vaccine formulation with the antigen MAP2698c and MONTANIDE™ ISA 201VG adjuvant produced strong whole-MAP as well as MAP2698c-specific IFN-γ responses in a high proportion of the vaccinated sheep. The formulation caused less severe injection site lesions in comparison to other formulations. The findings from this study suggest that the MAP2698c + 201VG should be evaluated in a challenge trial to determine the efficacy of this vaccine candidate. PMID:25077074

  2. Attenuated Mycobacterium tuberculosis SO2 vaccine candidate is unable to induce cell death.

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    Adriana Aporta

    Full Text Available It has been proposed that Mycobacterium tuberculosis virulent strains inhibit apoptosis and trigger cell death by necrosis of host macrophages to evade innate immunity, while non-virulent strains induce typical apoptosis activating a protective host response. As part of the characterization of a novel tuberculosis vaccine candidate, the M. tuberculosis phoP mutant SO2, we sought to evaluate its potential to induce host cell death. The parental M. tuberculosis MT103 strain and the current vaccine against tuberculosis Bacillus Calmette-Guérin (BCG were used as comparators in mouse models in vitro and in vivo. Our data reveal that attenuated SO2 was unable to induce apoptotic events neither in mouse macrophages in vitro nor during lung infection in vivo. In contrast, virulent MT103 triggers typical apoptotic events with phosphatidylserine exposure, caspase-3 activation and nuclear condensation and fragmentation. BCG strain behaved like SO2 and did not induce apoptosis. A clonogenic survival assay confirmed that viability of BCG- or SO2-infected macrophages was unaffected. Our results discard apoptosis as the protective mechanism induced by SO2 vaccine and provide evidence for positive correlation between classical apoptosis induction and virulent strains, suggesting apoptosis as a possible virulence determinant during M. tuberculosis infection.

  3. Considerations for the rational design of a Chlamydia vaccine

    OpenAIRE

    Liang, Steven; Bulir, David; Kaushic, Charu; Mahony, James

    2016-01-01

    ABSTRACT Chlamydia trachomatis is the leading cause of preventable blindness and the most common bacterial sexually transmitted infection. Remarkable progress in vaccine research over the past six?decades has led to the advancement of novel C. trachomatis vaccine candidates into clinical trials. However, many questions regarding the role of specific cellular populations and molecular mechanisms in protective immunity against human C. trachomatis genital tract infections remain unanswered. Bio...

  4. Transcription status of vaccine candidate genes of Plasmodium falciparum during the hepatic phase of its life cycle.

    NARCIS (Netherlands)

    Bodescot, M.; Silvie, O.; Siau, A.; Refour, P.; Pino, P.; Franetich, J.F.; Hannoun, L.; Sauerwein, R.W.; Mazier, D.

    2004-01-01

    The CSP, EMP2/MESA, MSP2, MSP3, MSP5, RAP1, RAP2, RESA1, SERA1 and SSP2/TRAP genes of Plasmodium falciparum are vaccine candidates. The hepatic phase of the infection is of major interest due to the protection induced by immunization with radiation-attenuated sporozoites. We therefore performed

  5. CD4+ T-cell Responses Among Adults and Young Children In Response to Streptococcus pneumoniae and Haemophilus influenzae Vaccine Candidate Protein Antigens

    OpenAIRE

    Sharma, Sharad K.; Roumanes, David; Almudevar, Anthony; Mosmann, Tim R.; Pichichero, Michael E.

    2013-01-01

    We characterized cytokine profiles of CD4+ T-helper (h) cells in adults and young children to ascertain if responses occur to next-generation candidate vaccine antigens PspA, PcpA, PhtD, PhtE, Ply, LytB of Streptococcus pneumonia (Spn) and Protein D and OMP26 of non-typeable Haemophilus influenzae (NTHi). Adults had vaccine antigen-specific Th1 - and Th2 cells responsive to all antigens evaluated whereas young children had significant numbers of vaccine antigen-specific CD4+ T cells producing...

  6. Naturally acquired antibody responses to recombinant Pfs230 and Pfs48/45 transmission blocking vaccine candidates.

    Science.gov (United States)

    Jones, Sophie; Grignard, Lynn; Nebie, Issa; Chilongola, Jaffu; Dodoo, Daniel; Sauerwein, Robert; Theisen, Michael; Roeffen, Will; Singh, Shrawan Kumar; Singh, Rajesh Kumar; Singh, Sanjay; Kyei-Baafour, Eric; Tetteh, Kevin; Drakeley, Chris; Bousema, Teun

    2015-07-01

    Pfs48/45 and Pfs230 are Plasmodium falciparum sexual stage proteins and promising malaria transmission-blocking vaccine candidates. Antibody responses against these proteins may be naturally acquired and target antigens may be under selective pressure. This has consequences for the future evaluation of vaccine immunogenicity and efficacy in populations naturally exposed to malaria. We determined naturally acquired antibody responses to the recombinant proteins Pfs48/45-10C and Pfs230-230CMB in children from three malaria endemic settings in Ghana, Tanzania and Burkina Faso. We also examined genetic polymorphisms in the P. falciparum gene pfs48/45. Antibody prevalence was 1.1-18.2% for 10C and 6.7-18.9% for 230CMB. In Burkina Faso we observed evidence of an age-dependent acquisition pattern for both 10C (p < 0.001) and 230CMB (p = 0.031). Membrane feeding assays on a separate dataset demonstrated an association between functional transmission reducing activity and antibody prevalence for both 10C (p = 0.017) and 230CMB (p = 0.049). 17 single nucleotide polymorphisms were found in pfs48/45 (from 126 samples), with 5 non-synonymous SNPs in the Pfs48/45 10C region. We conclude there are naturally acquired antibody responses to both vaccine candidates which have functional relevance by reducing the transmissibility of infected individuals. We identified genetic polymorphisms, in pfs48/45 which exhibited geographical specificity. Copyright © 2015 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  7. Protection against Fasciola gigantica using paramyosin antigen as a candidate for vaccine production.

    Science.gov (United States)

    Abou-Elhakam, H; Rabee, I; El Deeb, S; El Amir, A

    2013-11-15

    Yet no vaccine to protect ruminants against liver fluke infection has been commercialized. In an attempt to develop a suitable vaccine against Fasciola gigantica (F. gigantica) infection in rabbits, using 97 kDa Pmy antigen. It was found that, the mean worm burdens and bile egg count after challenge were reduced significantly by 58.40 and 61.40%, respectively. On the other hand, immunization of rabbits with Pmy induced a significant expression of humoral antibodies (IgM, total IgG, IgG1, IgG2 and IgG4) and different cytokines (IL-6, IL-10, L-12 and TNF-alpha). Among Ig isotypes, IgG2 and IgG4 were most dominant Post-infection (PI) while, recording a low IgG1 level. The dominance of IgG2 and IgG4 suggested late T helper1 (Th1) involvement in rabbit's cellular response. While, the low IgG1 level suggested Th2 response to adult F. gigantica worm Pmy. Among all cytokines, IL-10 was the highest in rabbits immunized with Pmy PI suggesting also the enhancement of Th2 response. It was clear that the native F. gigantica Pmy is considered as a relevant candidate for vaccination against fascioliasis. Also, these data suggested the immunoprophylactic effect of the native F. gigantica Pmy which is mediated by a mixed Th1/Th2 response.

  8. Pulmonary immunity and durable protection induced by the ID93/GLA-SE vaccine candidate against the hyper-virulent Korean Beijing Mycobacterium tuberculosis strain K.

    Science.gov (United States)

    Cha, Seung Bin; Kim, Woo Sik; Kim, Jong-Seok; Kim, Hongmin; Kwon, Kee Woong; Han, Seung Jung; Cho, Sang-Nae; Coler, Rhea N; Reed, Steven G; Shin, Sung Jae

    2016-04-27

    The majority of tuberculosis (TB) vaccine candidates advanced to clinical trials have been evaluated preclinically using laboratory-adapted strains. However, it has been proposed that challenge with clinical isolates in preclinical vaccine testing could provide further and more practical validation. Here, we tested the ID93/GLA-SE TB vaccine candidate against the clinical Mycobacterium tuberculosis (Mtb) strain K (Mtb K) belonging to the Beijing family, the most prevalent Mtb strain in South Korea. Mice immunized with ID93/GLA-SE exhibited a significant reduction in bacteria and reduced lung inflammation against Mtb K when compared to non-immunized controls. In addition, we analyzed the immune responses in the lungs of ID93/GLA-SE-immunized mice, and showed that ID93/GLA-SE was able to elicit sustained Th1-biased immune responses including antigen-specific multifunctional CD4(+) T cell co-producing IFN-γ, TNF-α, and IL-2 as well as a high magnitude of IFN-γ response for up to 10 weeks post-challenge. Notably, further investigation of T cell subsets in the lung following challenge showed remarkable generation of CD8(+) central memory T cells by ID93/GLA-SE-immunization. Our findings showed that ID93/GLA-SE vaccine confers a high level of robust protection against the hypervirulent Mtb Beijing infection which was characterized by pulmonary Th1-polarized T-cell immune responses. These findings may also provide relevant information for potential utility of this vaccine candidate in East-Asian countries where the Beijing genotype is highly prevalent. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Immunoprotective efficacy of Acinetobacter baumannii outer membrane protein, FilF, predicted in silico as a potential vaccine candidate

    Directory of Open Access Journals (Sweden)

    Ravinder eSingh

    2016-02-01

    Full Text Available Acinetobacter baumannii is emerging as a serious nosocomial pathogen with multidrug resistance that has made it difficult to cure and development of efficacious treatment against this pathogen is direly needed. This has led to investigate vaccine approach to prevent and treat A. baumannii infections. In this work, an outer membrane putative pilus assembly protein, FilF, was predicted as vaccine candidate by in silico analysis of A. baumannii proteome and was found to be conserved among the A. baumannii strains. It was cloned and expressed in E. coli BL21(DE3 and purified by Ni-NTA chromatography. Immunization with FilF generated high antibody titer (>64000 and provided 50% protection against a standardized lethal dose (10*8 CFU of A. baumannii in murine pneumonia model. FilF immunization reduced the bacterial load in lungs by 2 and 4 log cycles, 12 and 24 h post infection as compared to adjuvant control; reduced the levels of pro-inflammatory cytokines TNF-α, IL-6, IL-33, IFN-γ and IL-1β significantly and histology of lung tissue supported the data by showing considerably reduced damage and infiltration of neutrophils in lungs. These results demonstrate the in vivo validation of immunoprotective efficacy of a protein predicted as a vaccine candidate by in silico proteomic analysis and open the possibilities for exploration of a large array of uncharacterized proteins.

  10. Conservation and diversity of influenza A H1N1 HLA-restricted T cell epitope candidates for epitope-based vaccines.

    Directory of Open Access Journals (Sweden)

    Paul Thiamjoo Tan

    2010-01-01

    Full Text Available The immune-related evolution of influenza viruses is exceedingly complex and current vaccines against influenza must be reformulated for each influenza season because of the high degree of antigenic drift among circulating influenza strains. Delay in vaccine production is a serious problem in responding to a pandemic situation, such as that of the current H1N1 strain. Immune escape is generally attributed to reduced antibody recognition of the viral hemagglutinin and neuraminidase proteins whose rate of mutation is much greater than that of the internal non-structural proteins. As a possible alternative, vaccines directed at T cell epitope domains of internal influenza proteins, that are less susceptible to antigenic variation, have been investigated.HLA transgenic mouse strains expressing HLA class I A*0201, A*2402, and B*0702, and class II DRB1*1501, DRB1*0301 and DRB1*0401 were immunized with 196 influenza H1N1 peptides that contained residues of highly conserved proteome sequences of the human H1N1, H3N2, H1N2, H5N1, and avian influenza A strains. Fifty-four (54 peptides that elicited 63 HLA-restricted peptide-specific T cell epitope responses were identified by IFN-gamma ELISpot assay. The 54 peptides were compared to the 2007-2009 human H1N1 sequences for selection of sequences in the design of a new candidate H1N1 vaccine, specifically targeted to highly-conserved HLA-restricted T cell epitopes.Seventeen (17 T cell epitopes in PB1, PB2, and M1 were selected as vaccine targets based on sequence conservation over the past 30 years, high functional avidity, non-identity to human peptides, clustered localization, and promiscuity to multiple HLA alleles. These candidate vaccine antigen sequences may be applicable to any avian or human influenza A virus.

  11. GapA, a potential vaccine candidate antigen against Streptococcus agalactiae in Nile tilapia (Oreochromis niloticus).

    Science.gov (United States)

    Zhang, Ze; Yu, Angen; Lan, Jiangfeng; Zhang, Hua; Hu, Minqiang; Cheng, Jiewei; Zhao, Lijuan; Lin, Li; Wei, Shun

    2017-04-01

    Streptococcosis due to the bacterium Streptococcus agalactiae (S. agalactiae) has resulted in enormous economic losses in aquaculture worldwide, especially in the tilapia culture industry. Previously, there were limited vaccines that could be employed against streptococcosis in tilapia. This study aimed to develop a vaccine candidate using the glyceraldehyde-phosphate dehydrogenase protein (GapA) of S. agalactiae encoded by the gapA gene. Tilapia were intraperitoneally injected with PBS, PBS + Freund's adjuvant, PBS + Montanide's adjuvant, GapA + Freund's adjuvant, GapA + Montanide's adjuvant, killed S. agalactiae whole cells (WC)+Freund's adjuvant, or killed S. agalactiae whole cells (WC)+ Montanide's adjuvant. They were then challenged with S. agalactiae, and the relative percentage survival (RPS) was monitored 14 days after the challenge. The highest RPSs were observed in the WC groups, with 76.7% in WC + Freund's adjuvant and 74.4% in WC + Montanide's adjuvant groups; these were followed by the GapA groups, with 63.3% in GapA + Freund's adjuvant and 45.6% in GapA + Montanide's adjuvant groups. The RPS of the PBS group was 0%, and those of PBS + Freund's adjuvant and PBS + Montanide's adjuvant groups were 6.7% and 3.3%, respectively. Additionally, the IgM antibody responses elicited in GapA groups and WC groups were significantly higher than those in PBS groups. Furthermore, the expressions of cytokine (IL-1β and TNF-α) mRNAs in the GapA groups and WC groups were significantly higher than those in the PBS groups. Taken together, these results reveal that the GapA protein is a promising vaccine candidate that could be used to prevent streptococcosis in tilapia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Safety and tolerability of a live oral Salmonella typhimurium vaccine candidate in SIV-infected nonhuman primates.

    Science.gov (United States)

    Ault, Alida; Tennant, Sharon M; Gorres, J Patrick; Eckhaus, Michael; Sandler, Netanya G; Roque, Annelys; Livio, Sofie; Bao, Saran; Foulds, Kathryn E; Kao, Shing-Fen; Roederer, Mario; Schmidlein, Patrick; Boyd, Mary Adetinuke; Pasetti, Marcela F; Douek, Daniel C; Estes, Jacob D; Nabel, Gary J; Levine, Myron M; Rao, Srinivas S

    2013-12-02

    Nontyphoidal Salmonella (NTS) serovars are a common cause of acute food-borne gastroenteritis worldwide and can cause invasive systemic disease in young infants, the elderly, and immunocompromised hosts, accompanied by high case fatality. Vaccination against invasive NTS disease is warranted where the disease incidence and mortality are high and multidrug resistance is prevalent, as in sub-Saharan Africa. Live-attenuated vaccines that mimic natural infection constitute one strategy to elicit protection. However, they must particularly be shown to be adequately attenuated for consideration of immunocompromised subjects. Accordingly, we examined the safety and tolerability of an oral live attenuated Salmonella typhimurium vaccine candidate, CVD 1921, in an established chronic simian immunodeficiency virus (SIV)-infected rhesus macaque model. We evaluated clinical parameters, histopathology, and measured differences in mucosal permeability to wild-type and vaccine strains. Compared to the wild-type S. typhimurium strain I77 in both SIV-infected and SIV-uninfected nonhuman primate hosts, this live-attenuated vaccine shows reduced shedding and systemic spread, exhibits limited pathological disease manifestations in the digestive tract, and induces low levels of cellular infiltration in tissues. Furthermore, wild-type S. typhimurium induces increased intestinal epithelial damage and permeability, with infiltration of neutrophils and macrophages in both SIV-infected and SIV-uninfected nonhuman primates compared to the vaccine strain. Based on shedding, systemic spread, and histopathology, the live-attenuated S. typhimurium strain CVD 1921 appears to be safe and well-tolerated in the nonhuman primate model, including chronically SIV-infected rhesus macaques. Copyright © 2013. Published by Elsevier Ltd.

  13. Considerations for the rational design of a Chlamydia vaccine.

    Science.gov (United States)

    Liang, Steven; Bulir, David; Kaushic, Charu; Mahony, James

    2017-04-03

    Chlamydia trachomatis is the leading cause of preventable blindness and the most common bacterial sexually transmitted infection. Remarkable progress in vaccine research over the past six decades has led to the advancement of novel C. trachomatis vaccine candidates into clinical trials. However, many questions regarding the role of specific cellular populations and molecular mechanisms in protective immunity against human C. trachomatis genital tract infections remain unanswered. Biomarkers of vaccine induced protective immunity are elusive in humans, while a cautionary message on the translatability of data obtained from current animal models has emanated from vaccine research and development efforts against other important human pathogens. In this commentary, we highlight recent advances in Chlamydia vaccine development and discuss their implications in the context of a rational approach to the design of a human C. trachomatis vaccine.

  14. Chimeric Pestivirus Experimental Vaccines.

    Science.gov (United States)

    Reimann, Ilona; Blome, Sandra; Beer, Martin

    2016-01-01

    Chimeric pestiviruses have shown great potential as marker vaccine candidates against pestiviral infections. Exemplarily, we describe here the construction and testing of the most promising classical swine fever vaccine candidate "CP7_E2alf" in detail. The description is focused on classical cloning technologies in combination with reverse genetics.

  15. Need for a safe vaccine against respiratory syncytial virus infection

    Directory of Open Access Journals (Sweden)

    Joo-Young Kim

    2012-09-01

    Full Text Available Human respiratory syncytial virus (HRSV is a major cause of severe respiratory tract illnesses in infants and young children worldwide. Despite its importance as a respiratory pathogen, there is currently no licensed vaccine for HRSV. Following failure of the initial trial of formalin-inactivated virus particle vaccine, continuous efforts have been made for the development of safe and efficacious vaccines against HRSV. However, several obstacles persist that delay the development of HRSV vaccine, such as the immature immune system of newborn infants and the possible Th2-biased immune responses leading to subsequent vaccine-enhanced diseases. Many HRSV vaccine strategies are currently being developed and evaluated, including live-attenuated viruses, subunit-based, and vector-based candidates. In this review, the current HRSV vaccines are overviewed and the safety issues regarding asthma and vaccine-induced pathology are discussed.

  16. Controlling dengue with vaccines in Thailand.

    Directory of Open Access Journals (Sweden)

    Dennis L Chao

    Full Text Available Dengue is a mosquito-borne infectious disease that constitutes a growing global threat with the habitat expansion of its vectors Aedes aegyti and A. albopictus and increasing urbanization. With no effective treatment and limited success of vector control, dengue vaccines constitute the best control measure for the foreseeable future. With four interacting dengue serotypes, the development of an effective vaccine has been a challenge. Several dengue vaccine candidates are currently being tested in clinical trials. Before the widespread introduction of a new dengue vaccine, one needs to consider how best to use limited supplies of vaccine given the complex dengue transmission dynamics and the immunological interaction among the four dengue serotypes.We developed an individual-level (including both humans and mosquitoes, stochastic simulation model for dengue transmission and control in a semi-rural area in Thailand. We calibrated the model to dengue serotype-specific infection, illness and hospitalization data from Thailand. Our simulations show that a realistic roll-out plan, starting with young children then covering progressively older individuals in following seasons, could reduce local transmission of dengue to low levels. Simulations indicate that this strategy could avert about 7,700 uncomplicated dengue fever cases and 220 dengue hospitalizations per 100,000 people at risk over a ten-year period.Vaccination will have an important role in controlling dengue. According to our modeling results, children should be prioritized to receive vaccine, but adults will also need to be vaccinated if one wants to reduce community-wide dengue transmission to low levels.

  17. Controlling Dengue with Vaccines in Thailand

    Science.gov (United States)

    Chao, Dennis L.; Halstead, Scott B.; Halloran, M. Elizabeth; Longini, Ira M.

    2012-01-01

    Background Dengue is a mosquito-borne infectious disease that constitutes a growing global threat with the habitat expansion of its vectors Aedes aegyti and A. albopictus and increasing urbanization. With no effective treatment and limited success of vector control, dengue vaccines constitute the best control measure for the foreseeable future. With four interacting dengue serotypes, the development of an effective vaccine has been a challenge. Several dengue vaccine candidates are currently being tested in clinical trials. Before the widespread introduction of a new dengue vaccine, one needs to consider how best to use limited supplies of vaccine given the complex dengue transmission dynamics and the immunological interaction among the four dengue serotypes. Methodology/Principal Findings We developed an individual-level (including both humans and mosquitoes), stochastic simulation model for dengue transmission and control in a semi-rural area in Thailand. We calibrated the model to dengue serotype-specific infection, illness and hospitalization data from Thailand. Our simulations show that a realistic roll-out plan, starting with young children then covering progressively older individuals in following seasons, could reduce local transmission of dengue to low levels. Simulations indicate that this strategy could avert about 7,700 uncomplicated dengue fever cases and 220 dengue hospitalizations per 100,000 people at risk over a ten-year period. Conclusions/Significance Vaccination will have an important role in controlling dengue. According to our modeling results, children should be prioritized to receive vaccine, but adults will also need to be vaccinated if one wants to reduce community-wide dengue transmission to low levels. PMID:23145197

  18. Vaccine Adverse Events Reported during the First Ten Years (1998–2008 after Introduction in the State of Rondonia, Brazil

    Directory of Open Access Journals (Sweden)

    Mônica P. L. Cunha

    2013-01-01

    Full Text Available Despite good safety records, vaccines given to young children can cause adverse events. We investigated the reported adverse events following immunization (AEFI of vaccines given to children of less than seven years of age during the first ten years (1998 to 2008 in the state of Rondonia, Brazil. We worked with the events related to BCG (Bacillus Calmett-Guérin, HB (hepatitis B, DTwP/Hib (diphtheria-tetanus-pertussis+Hemophillus influenza b, DTP (diphtheria-tetanus-pertussis, MMR (mumps, measles, rubella, and YF (yellow fever vaccines because they were part of the recommended scheme. The number of doses of vaccines given was 3,231,567 with an average of AEFI of 57.2/year during the studied period. DTwP/Hib was responsible for 298 (57.8%, DTP 114 (22.9%, HB 31 (6%, MMR 28 (5.4%, BCG 24 (4.7%, and YF 20 (3.9% of the reported AEFI. The combination of the AEFI for DTwP/Hib vaccines showed the highest number of systemic (61.4% and local events (33.8%. Young children (≤1-year old were more susceptible to AEFI occurring in the 6 hours (54.2% following vaccine uptake. This study suggests significant differences in reactogenicity of vaccines and that despite limitations of the AEFI Brazilian registry system we cannot ignore underreporting and should use the system to expand our understanding of adverse events and effects.

  19. Challenges to developing effective streptococcal vaccines to prevent rheumatic fever and rheumatic heart disease

    Directory of Open Access Journals (Sweden)

    Sharma A

    2014-05-01

    Full Text Available Abhinay Sharma, D Patric Nitsche-SchmitzDepartment of Medical Microbiology, Helmholtz Center for Infection Research, Braunschweig, GermanyAbstract: Acute rheumatic fever is a sequela of Streptococcus pyogenes and potentially of Streptococcus dysgalactiae subsp. equisimilis infections. Acute rheumatic fever is caused by destructive autoimmunity and inflammation in the extracellular matrix and can lead to rheumatic heart disease, which is the most frequent cardiologic disease that is acquired in youth. Although effective treatments are available, acute rheumatic fever and rheumatic heart disease remain serious threats to human health, which affect millions and cause high economic losses. This has motivated the search for a vaccine that prevents the causative streptococcal infections. A variety of potential vaccine candidates have been identified and investigated in the past. Today, new approaches are applied to find alternative candidates. Nevertheless, several obstacles lie in the way of an approved S. pyogenes vaccine for use in humans. Herein, a subjective selection of promising vaccine candidates with respect to the prevention of acute rheumatic fever/rheumatic heart disease and safety regarding immunological side effects is discussed.Keywords: autoimmune disease, side effects, M protein vaccine, molecular mimicry, coiled-coil, collagen binding, PARF

  20. Evaluation of a genetically modified foot-and-mouth disease virus vaccine candidate generated by reverse genetics

    Science.gov (United States)

    2012-01-01

    . Thus, the full-length cDNA clone of FMDV can be a useful tool to develop genetically engineered FMDV vaccine candidates to help control porcinophilic FMD epidemics in China. PMID:22591597

  1. Evaluation of a genetically modified foot-and-mouth disease virus vaccine candidate generated by reverse genetics

    Directory of Open Access Journals (Sweden)

    Li Pinghua

    2012-05-01

    wild O/HN/CHA/93 virus. Thus, the full-length cDNA clone of FMDV can be a useful tool to develop genetically engineered FMDV vaccine candidates to help control porcinophilic FMD epidemics in China.

  2. Next-Generation Dengue Vaccines: Novel Strategies Currently Under Development

    Directory of Open Access Journals (Sweden)

    Anna P. Durbin

    2011-09-01

    Full Text Available Dengue has become the most important arboviral infection worldwide with more than 30 million cases of dengue fever estimated to occur each year. The need for a dengue vaccine is great and several live attenuated dengue candidate vaccines are proceeding through clinical evaluation. The need to induce a balanced immune response against all four DENV serotypes with a single vaccine has been a challenge for dengue vaccine developers. A live attenuated DENV chimeric vaccine produced by Sanofi Pasteur has recently entered Phase III evaluation in numerous dengue-endemic regions of the world. Viral interference between serotypes contained in live vaccines has required up to three doses of the vaccine be given over a 12-month period of time. For this reason, novel DENV candidate vaccines are being developed with the goal of achieving a protective immune response with an immunization schedule that can be given over the course of a few months. These next-generation candidates include DNA vaccines, recombinant adenovirus vectored vaccines, alphavirus replicons, and sub-unit protein vaccines. Several of these novel candidates will be discussed.

  3. Next-generation dengue vaccines: novel strategies currently under development.

    Science.gov (United States)

    Durbin, Anna P; Whitehead, Stephen S

    2011-10-01

    Dengue has become the most important arboviral infection worldwide with more than 30 million cases of dengue fever estimated to occur each year. The need for a dengue vaccine is great and several live attenuated dengue candidate vaccines are proceeding through clinical evaluation. The need to induce a balanced immune response against all four DENV serotypes with a single vaccine has been a challenge for dengue vaccine developers. A live attenuated DENV chimeric vaccine produced by Sanofi Pasteur has recently entered Phase III evaluation in numerous dengue-endemic regions of the world. Viral interference between serotypes contained in live vaccines has required up to three doses of the vaccine be given over a 12-month period of time. For this reason, novel DENV candidate vaccines are being developed with the goal of achieving a protective immune response with an immunization schedule that can be given over the course of a few months. These next-generation candidates include DNA vaccines, recombinant adenovirus vectored vaccines, alphavirus replicons, and sub-unit protein vaccines. Several of these novel candidates will be discussed.

  4. The effect of current Schistosoma mansoni infection on the immunogenicity of a candidate TB vaccine, MVA85A, in BCG-vaccinated adolescents: An open-label trial.

    Directory of Open Access Journals (Sweden)

    Anne Wajja

    2017-05-01

    Full Text Available Helminth infection may affect vaccine immunogenicity and efficacy. Adolescents, a target population for tuberculosis booster vaccines, often have a high helminth burden. We investigated effects of Schistosoma mansoni (Sm on the immunogenicity and safety of MVA85A, a model candidate tuberculosis vaccine, in BCG-vaccinated Ugandan adolescents.In this phase II open label trial we enrolled 36 healthy, previously BCG-vaccinated adolescents, 18 with no helminth infection detected, 18 with Sm only. The primary outcome was immunogenicity measured by Ag85A-specific interferon gamma ELISpot assay. Tuberculosis and schistosome-specific responses were also assessed by whole-blood stimulation and multiplex cytokine assay, and by antibody ELISAs.Ag85A-specific cellular responses increased significantly following immunisation but with no differences between the two groups. Sm infection was associated with higher pre-immunisation Ag85A-specific IgG4 but with no change in antibody levels following immunisation. There were no serious adverse events. Most reactogenicity events were of mild or moderate severity and resolved quickly.The significant Ag85A-specific T cell responses and lack of difference between Sm-infected and uninfected participants is encouraging for tuberculosis vaccine development. The implications of pre-existing Ag85A-specific IgG4 antibodies for protective immunity against tuberculosis among those infected with Sm are not known. MVA85A was safe in this population.ClinicalTrials.gov NCT02178748.

  5. Safety and immunogenicity of the malaria vaccine candidate MSP3 long synthetic peptide in 12-24 months-old Burkinabe children.

    NARCIS (Netherlands)

    Sirima, S.B.; Tiono, A.B.; Diarra, A.; Ouedraogo, A.L.; Yaro, J.B.; Ouedraogo, E.; Gansane, A.; Bougouma, E.C.; Konate, A.T.; Kabore, Y.; Traore, A.; Roma, C.; Soulama, I.; Luty, A.J.F.; Cousens, S.; Nebie, I.

    2009-01-01

    BACKGROUND: A Phase Ia trial in European volunteers of the candidate vaccine merozoite surface protein 3 (MSP3), a Plasmodium falciparum blood stage membrane, showed that it induces biologically active antibodies able to achieve parasite killing in vitro, while a phase Ib trial in semi-immune adult

  6. Potential public health impact of RTS,S malaria candidate vaccine in sub-Saharan Africa: a modelling study.

    Science.gov (United States)

    Sauboin, Christophe J; Van Bellinghen, Laure-Anne; Van De Velde, Nicolas; Van Vlaenderen, Ilse

    2015-12-23

    Adding malaria vaccination to existing interventions could help to reduce the health burden due to malaria. This study modelled the potential public health impact of the RTS,S candidate malaria vaccine in 42 malaria-endemic countries in sub-Saharan Africa. An individual-based Markov cohort model was constructed with three categories of malaria transmission intensity and six successive malaria immunity levels. The cycle time was 5 days. Vaccination was assumed to reduce the risk of infection, with no other effects. Vaccine efficacy was assumed to wane exponentially over time. Malaria incidence and vaccine efficacy data were taken from a Phase III trial of the RTS,S vaccine with 18 months of follow-up (NCT00866619). The model was calibrated to reproduce the malaria incidence in the control arm of the trial in each transmission category and published age distribution data. Individual-level heterogeneity in malaria exposure and vaccine protection was accounted for. Parameter uncertainty and variability were captured by using stochastic model transitions. The model followed a cohort from birth to 10 years of age without malaria vaccination, or with RTS,S malaria vaccination administered at age 6, 10 and 14 weeks or at age 6, 7-and-a-half and 9 months. Median and 95% confidence intervals were calculated for the number of clinical malaria cases, severe cases, malaria hospitalizations and malaria deaths expected to be averted by each vaccination strategy. Univariate sensitivity analysis was conducted by varying the values of key input parameters. Vaccination assuming the coverage of diphtheria-tetanus-pertussis (DTP3) at age 6, 10 and 14 weeks is estimated to avert over five million clinical malaria cases, 119,000 severe malaria cases, 98,600 malaria hospitalizations and 31,000 malaria deaths in the 42 countries over the 10-year period. Vaccination at age 6, 7-and-a-half and 9 months with 75% of DTP3 coverage is estimated to avert almost 12.5 million clinical malaria cases

  7. Leishmania infantum HSP70-II null mutant as candidate vaccine against leishmaniasis: a preliminary evaluation

    Directory of Open Access Journals (Sweden)

    Fresno Manuel

    2011-07-01

    Full Text Available Abstract Background Visceral leishmaniasis is the most severe form of leishmaniasis and no effective vaccine exists. The use of live attenuated vaccines is emerging as a promising vaccination strategy. Results In this study, we tested the ability of a Leishmania infantum deletion mutant, lacking both HSP70-II alleles (ΔHSP70-II, to provide protection against Leishmania infection in the L. major-BALB/c infection model. Administration of the mutant line by either intraperitoneal, intravenous or subcutaneous route invariably leads to the production of high levels of NO and the development in mice of type 1 immune responses, as determined by analysis of anti-Leishmania IgG subclasses. In addition, we have shown that ΔHSP70-II would be a safe live vaccine as immunodeficient SCID mice, and hamsters (Mesocricetus auratus, infected with mutant parasites did not develop any sign of pathology. Conclusions The results suggest that the ΔHSP70-II mutant is a promising and safe vaccine, but further studies in more appropriate animal models (hamsters and dogs are needed to appraise whether this attenuate mutant would be useful as vaccine against visceral leishmaniasis.

  8. Dengue vaccine: come let's fight the menace.

    Science.gov (United States)

    Chawla, Sumit; Sahoo, Soumya Swaroop; Singh, Inderjeet; Verma, Madhur; Gupta, Vikas; Kumari, Sneh

    2015-01-01

    Although dengue has a global distribution, the World Health Organization (WHO) South-East Asia region together with Western Pacific region bears nearly 75% of the current global disease burden. Globally, the societal burden has been estimated to be approximately 528 to 1300 disability-adjusted life years (DALY) per million to populations in endemic regions Dengue is believed to infect 50 to 100 million people worldwide a year with half a million life-threatening infections requiring hospitalization, resulting in approximately 12,500 to 25,000 deaths. Despite being known for decades and nearly half the world's population is at risk for infection with as many as 100 million cases occurring annually, the pitiable state is that we still have no antiviral drugs to treat it and no vaccines to prevent it. In recent years, however, the development of dengue vaccines has accelerated dramatically in tandem with the burgeoning dengue problem with a rejuvenated vigour. However, recent progress in molecular-based vaccine strategies, as well as a renewed commitment by the World Health Organization (WHO) to co-ordinate global efforts on vaccine development, finally provides hope that control of this serious disease may be at hand. Today, several vaccines are in various stages of advanced development, with clinical trials currently underway on 5 candidate vaccines. Trials in the most advanced stages are showing encouraging preliminary data, and the leading candidate could be licensed as early as 2015.

  9. Naturally acquired antibody responses to recombinant Pfs230 and Pfs48/45 transmission blocking vaccine candidates

    DEFF Research Database (Denmark)

    Jones, Sophie; Grignard, Lynn; Nebie, Issa

    2015-01-01

    for the future evaluation of vaccine immunogenicity and efficacy in populations naturally exposed to malaria. METHODS: We determined naturally acquired antibody responses to the recombinant proteins Pfs48/45-10C and Pfs230-230CMB in children from three malaria endemic settings in Ghana, Tanzania and Burkina Faso......OBJECTIVES: Pfs48/45 and Pfs230 are Plasmodium falciparum sexual stage proteins and promising malaria transmission-blocking vaccine candidates. Antibody responses against these proteins may be naturally acquired and target antigens may be under selective pressure. This has consequences....... We also examined genetic polymorphisms in the P. falciparum gene pfs48/45. RESULTS: Antibody prevalence was 1.1-18.2% for 10C and 6.7-18.9% for 230CMB. In Burkina Faso we observed evidence of an age-dependent acquisition pattern for both 10C (p assays...

  10. Identification of mutations in the M RNA of a candidate vaccine strain of Rift Valley fever virus.

    Science.gov (United States)

    Takehara, K; Min, M K; Battles, J K; Sugiyama, K; Emery, V C; Dalrymple, J M; Bishop, D H

    1989-04-01

    The M RNA species of a candidate vaccine strain of Rift Valley fever virus (RVFV ZH-548M12), derived by consecutive high level mutagenesis using 5-fluorouracil (H. Caplen, C. J. Peters, and D. H. L. Bishop, J. Gen. Virol., 66, 2271-2277, 1985), has been cloned and the cDNA sequenced. The data have been compared to those obtained for the parent virus strain RVFV ZH-548 as well as the previously published data for RVFV ZH-501 (M. S. Collett, A. F. Purchio, K. Keegan, S. Frazier, W. Hays, D. K. Anderson, M. D. Parker, C. Schmaljohn, J. Schmidt, and J. M. Dalrymple, Virology, 144, 228-245, 1985). Some eight nucleotide and three amino acid differences were identified between the M RNAs of ZH-501 and ZH-548. Between the M RNAs of ZH-548 and that of the M12 mutant there were 12 nucleotide and 7 amino acid changes. Unique to the mutant virus is a new AUG codon upstream of that which initiates the open reading frame of the RVFV M gene product (the viral glycoprotein precursor). The significance of this and other differences in the mutant RNA with regard to the derivation and potential attenuation of the candidate vaccine is discussed.

  11. Current Ebola vaccines

    Science.gov (United States)

    Hoenen, Thomas; Groseth, Allison; Feldmann, Heinz

    2012-01-01

    Introduction Ebolaviruses cause severe viral hemorrhagic fever in humans and non-human primates, with case fatality rates of up to 90%. Currently, neither a specific treatment nor a vaccine licensed for use in humans is available. However, a number of vaccine candidates have been developed in the last decade that are highly protective in non-human primates, the gold standard animal model for Ebola hemorrhagic fever. Areas covered This review analyzes a number of scenarios for the use of ebolavirus vaccines, discusses the requirements for ebolavirus vaccines in these scenarios, and describes current ebolavirus vaccines. Among these vaccines are recombinant Adenoviruses, recombinant Vesicular Stomatitis viruses, recombinant Human Parainfluenza viruses and virus-like particles. Interestingly, one of these vaccine platforms, based on recombinant Vesicular Stomatitis viruses, has also demonstrated post-exposure protection in non-human primates. Expert opinion The most pressing remaining challenge is now to move these vaccine candidates forward into human trials and towards licensure. In order to achieve this, it will be necessary to establish the mechanisms and correlates of protection for these vaccines, and to continue to demonstrate their safety, particularly in potentially immunocompromised populations. However, already now there is sufficient evidence that, from a scientific perspective, a vaccine protective against ebolaviruses is possible. PMID:22559078

  12. Evaluation of Live Recombinant Nonpathogenic Leishmania tarentolae Expressing Cysteine Proteinase and A2 Genes as a Candidate Vaccine against Experimental Canine Visceral Leishmaniasis.

    Directory of Open Access Journals (Sweden)

    Mehdi Shahbazi

    Full Text Available Canine Visceral Leishmaniasis (CVL is a major veterinary and public health problem caused by Leishmania infantum (L. infantum in many endemic countries. It is a severe chronic disease with generalized parasite spread to the reticuloendothelial system, such as spleen, liver and bone marrow and is often fatal when left untreated. Control of VL in dogs would dramatically decrease infection pressure of L. infantum for humans, since dogs are the main domestic reservoir. In the past decade, various subunits and DNA antigens have been identified as potential vaccine candidates in experimental animal models, but none has been approved for human use so far. In this study, we vaccinated outbreed dogs with a prime-boost regimen based on recombinant L. tarentolae expressing the L. donovani A2 antigen along with cysteine proteinase genes (CPA and CPB without its unusual C-terminal extension (CPB-CTE and evaluated its immunogenicity and protective immunity against L. infantum infectious challenge. We showed that vaccinated animals produced significantly higher levels of IgG2, but not IgG1, and also IFN-γ and TNF-α, but low IL-10 levels, before and after challenge as compared to control animals. Protection in dogs was also correlated with a strong DTH response and low parasite burden in the vaccinated group. Altogether, immunization with recombinant L. tarentolae A2-CPA-CPB-CTE was proven to be immunogenic and induced partial protection in dogs, hence representing a promising live vaccine candidate against CVL.

  13. Evaluation of Live Recombinant Nonpathogenic Leishmania tarentolae Expressing Cysteine Proteinase and A2 Genes as a Candidate Vaccine against Experimental Canine Visceral Leishmaniasis

    Science.gov (United States)

    Shahbazi, Mehdi; Zahedifard, Farnaz; Taheri, Tahereh; Taslimi, Yasaman; Jamshidi, Shahram; Shirian, Sadegh; Mahdavi, Niousha; Hassankhani, Mehdi; Daneshbod, Yahya; Zarkesh-Esfahani, Sayyed Hamid; Papadopoulou, Barbara; Rafati, Sima

    2015-01-01

    Canine Visceral Leishmaniasis (CVL) is a major veterinary and public health problem caused by Leishmania infantum (L. infantum) in many endemic countries. It is a severe chronic disease with generalized parasite spread to the reticuloendothelial system, such as spleen, liver and bone marrow and is often fatal when left untreated. Control of VL in dogs would dramatically decrease infection pressure of L. infantum for humans, since dogs are the main domestic reservoir. In the past decade, various subunits and DNA antigens have been identified as potential vaccine candidates in experimental animal models, but none has been approved for human use so far. In this study, we vaccinated outbreed dogs with a prime-boost regimen based on recombinant L. tarentolae expressing the L. donovani A2 antigen along with cysteine proteinase genes (CPA and CPB without its unusual C-terminal extension (CPB-CTE) and evaluated its immunogenicity and protective immunity against L. infantum infectious challenge. We showed that vaccinated animals produced significantly higher levels of IgG2, but not IgG1, and also IFN-γ and TNF-α, but low IL-10 levels, before and after challenge as compared to control animals. Protection in dogs was also correlated with a strong DTH response and low parasite burden in the vaccinated group. Altogether, immunization with recombinant L. tarentolae A2-CPA-CPB-CTE was proven to be immunogenic and induced partial protection in dogs, hence representing a promising live vaccine candidate against CVL. PMID:26197085

  14. Future of human Chlamydia vaccine: potential of self-adjuvanting biodegradable nanoparticles as safe vaccine delivery vehicles.

    Science.gov (United States)

    Sahu, Rajnish; Verma, Richa; Dixit, Saurabh; Igietseme, Joseph U; Black, Carolyn M; Duncan, Skyla; Singh, Shree R; Dennis, Vida A

    2018-03-01

    There is a persisting global burden and considerable public health challenge by the plethora of ocular, genital and respiratory diseases caused by members of the Gram-negative bacteria of the genus Chlamydia. The major diseases are conjunctivitis and blinding trachoma, non-gonococcal urethritis, cervicitis, pelvic inflammatory disease, ectopic pregnancy, tubal factor infertility, and interstitial pneumonia. The failures in screening and other prevention programs led to the current medical opinion that an efficacious prophylactic vaccine is the best approach to protect humans from chlamydial infections. Unfortunately, there is no human Chlamydia vaccine despite successful veterinary vaccines. A major challenge has been the effective delivery of vaccine antigens to induce safe and effective immune effectors to confer long-term protective immunity. The dawn of the era of biodegradable polymeric nanoparticles and the adjuvanted derivatives may accelerate the realization of the dream of human vaccine in the foreseeable future. Areas covered: This review focuses on the current status of human chlamydial vaccine research, specifically the potential of biodegradable polymeric nanovaccines to provide efficacious Chlamydia vaccines in the near future. Expert commentary: The safety of biodegradable polymeric nanoparticles-based experimental vaccines with or without adjuvants and the array of available chlamydial vaccine candidates would suggest that clinical trials in humans may be imminent. Also, the promising results from vaccine testing in animal models could lead to human vaccines against trachoma and reproductive diseases simultaneously.

  15. [Towards a new vaccine economy?].

    Science.gov (United States)

    Poirot, P; Martin, J F

    1994-01-01

    When Jonas Salk announced in the mid-50s the availability of a new vaccine against poliomyelitis, the world had the impression that it was now controlling infectious diseases. In fact, the success of this vaccine has been considerable and although some innovations lead to the launch of vaccines against flu, measles, rubella or mumps, the world vaccine market remained remarkably stable till the mid-80s. However, since 1984 (launch of the hepatitis B vaccine) there have been very substantial changes and further change is expected in the next ten years in the world market. Today, big companies are making a concentrated supply: Pasteur Mérieux with its subsidiary Connaught, SmithKline Beecham who acquired the Belgian company RIT, and Merck & Co. who is joining its forces with Pasteur Mérieux. Medium sized and small companies remain and reflect the situation of the past, but must work hard to secure their long term existence eventhough the world demand is going to double before the year 2000. Very substantial technological innovations explain to a large extent the development of the supply: progress in molecular biology, and particularly genetic engineering, lead to recombinant vaccines of which hepatitis B is the best example with worldwide sales in the range of $600 million a year. Similarly, conjugation technologies have allowed the development of new vaccines against meningitis, particularly Haemophilus influenzae type b. More recently, an efficacious vaccine against hepatitis A has been launched and many new products will be marketed in the next years against herpes, Lyme disease, and agents of other meningitis, etc.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Safety Lead Optimization and Candidate Identification: Integrating New Technologies into Decision-Making.

    Science.gov (United States)

    Dambach, Donna M; Misner, Dinah; Brock, Mathew; Fullerton, Aaron; Proctor, William; Maher, Jonathan; Lee, Dong; Ford, Kevin; Diaz, Dolores

    2016-04-18

    Discovery toxicology focuses on the identification of the most promising drug candidates through the development and implementation of lead optimization strategies and hypothesis-driven investigation of issues that enable rational and informed decision-making. The major goals are to [a] identify and progress the drug candidate with the best overall drug safety profile for a therapeutic area, [b] remove the most toxic drugs from the portfolio prior to entry into humans to reduce clinical attrition due to toxicity, and [c] establish a well-characterized hazard and translational risk profile to enable clinical trial designs. This is accomplished through a framework that balances the multiple considerations to identify a drug candidate with the overall best drug characteristics and provides a cogent understanding of mechanisms of toxicity. The framework components include establishing a target candidate profile for each program that defines the qualities of a successful candidate based on the intended therapeutic area, including the risk tolerance for liabilities; evaluating potential liabilities that may result from engaging the therapeutic target (pharmacology-mediated or on-target) and that are chemical structure-mediated (off-target); and characterizing identified liabilities. Lead optimization and investigation relies upon the integrated use of a variety of technologies and models (in silico, in vitro, and in vivo) that have achieved a sufficient level of qualification or validation to provide confidence in their use. We describe the strategic applications of various nonclinical models (established and new) for a holistic and integrated risk assessment that is used for rational decision-making. While this review focuses on strategies for small molecules, the overall concepts, approaches, and technologies are generally applicable to biotherapeutics.

  17. A Semi-Synthetic Glycoconjugate Vaccine Candidate for Carbapenem-Resistant Klebsiella pneumoniae.

    Science.gov (United States)

    Seeberger, Peter H; Pereira, Claney L; Khan, Naeem; Xiao, Guozhi; Diago-Navarro, Elizabeth; Reppe, Katrin; Opitz, Bastian; Fries, Bettina C; Witzenrath, Martin

    2017-11-06

    Hospital-acquired infections are an increasingly serious health concern. Infections caused by carpabenem-resistant Klebsiella pneumoniae (CR-Kp) are especially problematic, with a 50 % average survival rate. CR-Kp are isolated from patients with ever greater frequency, 7 % within the EU but 62 % in Greece. At a time when antibiotics are becoming less effective, no vaccines to protect from this severe bacterial infection exist. Herein, we describe the convergent [3+3] synthesis of the hexasaccharide repeating unit from its capsular polysaccharide and related sequences. Immunization with the synthetic hexasaccharide 1 glycoconjugate resulted in high titers of cross-reactive antibodies against CR-Kp CPS in mice and rabbits. Whole-cell ELISA was used to establish the surface staining of CR-Kp strains. The antibodies raised were found to promote phagocytosis. Thus, this semi-synthetic glycoconjugate is a lead for the development of a vaccine against a rapidly progressing, deadly bacterium. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Assessment of Lactobacillus gasseri as a candidate oral vaccine vector.

    Science.gov (United States)

    Stoeker, Laura; Nordone, Shila; Gunderson, Sara; Zhang, Lin; Kajikawa, Akinobu; LaVoy, Alora; Miller, Michael; Klaenhammer, Todd R; Dean, Gregg A

    2011-11-01

    Lactobacillus species are commensal bacteria that have long been recognized as probiotic microbes and are generally regarded as safe (GRAS) for human consumption. We have investigated the use of L. gasseri as a vaccine vector for oral immunization against mucosal pathogens. Recent research has shown that the immune response to different lactobacilli can vary widely depending on the species or subspecies of Lactobacillus being studied. While some lactobacilli seem to induce oral tolerance, others induce an adaptive immune response. This study characterized the systemic and mucosal immune response to wild-type and genetically modified L. gasseri. L. gasseri primarily activates TLR2/6, with additional activation through the TLR2 homodimer. To expand the Toll-like receptor (TLR) activation profile of L. gasseri and the immunogenicity of the vector, a plasmid containing fliC, the gene encoding bacterial flagellin, was introduced which resulted in the strong activation of TLR5. The treatment of human myeloid dendritic cells with recombinant lactobacilli expressing flagellin triggered phenotypic maturation and the release of proinflammatory cytokines. In contrast, bacterial treatment also resulted in a statistically significant increase in IL-10 production. In vivo studies established that treatment with L. gasseri led to a diversification of B-cell populations in the lamina propria of the murine colon. Furthermore, treatment with genetically modified L. gasseri led to a significant decrease in the percentage of FoxP3(+) colonic lymphocytes. Taken together, these data clarify the interaction of L. gasseri with the host immune system and support further investigation of the in vivo immunogenicity of L. gasseri expressing both flagellin and candidate vaccine antigens.

  19. Oral vaccination: where we are?

    Science.gov (United States)

    Silin, Dmytro S; Lyubomska, Oksana V; Jirathitikal, Vichai; Bourinbaiar, Aldar S

    2007-07-01

    As early as 900 years ago, the Bedouins of the Negev desert were reported to kill a rabid dog, roast its liver and feed it to a dog-bitten person for three to five days according to the size and number of bites [1] . In sixteenth century China, physicians routinely prescribed pills made from the fleas collected from sick cows, which purportedly prevented smallpox. One may dismiss the wisdom of the Bedouins or Chinese but the Nobel laureate, Charles Richet, demonstrated in 1900 that feeding raw meat can cure tuberculous dogs - an approach he termed zomotherapy. Despite historical clues indicating the feasibility of oral vaccination, this particular field is notoriously infamous for the abundance of dead-end leads. Today, most commercial vaccines are delivered by injection, which has the principal limitation that recipients do not like needles. In the last few years, there has been a sharp increase in interest in needle-free vaccine delivery; new data emerges almost daily in the literature. So far, there are very few licensed oral vaccines, but many more vaccine candidates are in development. Vaccines delivered orally have the potential to take immunization to a fundamentally new level. In this review, the authors summarize the recent progress in the area of oral vaccines.

  20. Conventional influenza vaccines influence the performance of a universal influenza vaccine in mice.

    Science.gov (United States)

    Rowell, Janelle; Lo, Chia-Yun; Price, Graeme E; Misplon, Julia A; Epstein, Suzanne L; Garcia, Mayra

    2018-02-08

    Universal influenza vaccines are designed to protect against diverse strains of influenza virus. Preclinical testing of new vaccine candidates is usually done in naïve animals, despite intended use in the human population with its varied immune history including responses to previous vaccinations. As an approach more relevant to human use, we tested a candidate universal influenza vaccine in mice with a history of conventional vaccination. Female BALB/c mice were given two intramuscular doses of inactivated influenza vaccine (IIV) or diphtheria and tetanus toxoids vaccine (DT), one month apart. Another group was given two intranasal doses of live attenuated influenza virus (LAIV). One month after the second dose, mice were given the universal influenza vaccine: recombinant adenoviruses expressing influenza A nucleoprotein (A/NP) and matrix 2 (M2) (A/NP + M2-rAd). Immune responses to universal vaccine antigens A/NP and M2 were assessed by ELISA and interferon-γ ELISPOT. Protection was tested by challenge with mouse-adapted A/FM/1/47 (H1N1) and monitoring for weight loss and survival. Universal vaccine performance was enhanced, inhibited or unaffected by particular prior vaccinations. Mice given Afluria IIV and LAIV had greater antibody and T-cell response to A/NP than mice without prior vaccination, providing examples of enhanced A/NP + M2-rAd performance. Though Fluvirin IIV partially inhibited, the universal vaccine still provided considerable protection unlike conventional vaccination. Fluzone IIV and DT had no effect on A/NP + M2-rAd performance. Thus our results demonstrate that universal vaccine candidate A/NP + M2-rAd was at least partially effective in mice with diverse prior histories. However, the degree of protection and nature of the immune responses may be affected by a history of conventional vaccination and suggests that performance in humans would be influenced by immune history. Published by Elsevier Ltd.

  1. Au-Ge based Candidate Alloys for High-Temperature Lead-Free Solder Alternatives

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hald, John; Hattel, Jesper Henri

    2009-01-01

    Au-Ge based candidate alloys have been proposed as an alternative to high-lead content solders that are currently being used for high-temperature applications. The influence of the low melting point metals namely In, Sb and Sn to the Au-Ge eutectic with respect to the microstructure and microhard......Au-Ge based candidate alloys have been proposed as an alternative to high-lead content solders that are currently being used for high-temperature applications. The influence of the low melting point metals namely In, Sb and Sn to the Au-Ge eutectic with respect to the microstructure...... was primarily strengthened by the refined (Ge) dispersed phase. The distribution of phases played a relatively more crucial role in determining the ductility of the bulk solder alloy. In the present work it was found that among the low melting point metals, the addition of Sb to the Au-Ge eutectic would...

  2. A Library of Plasmodium vivax Recombinant Merozoite Proteins Reveals New Vaccine Candidates and Protein-Protein Interactions

    Science.gov (United States)

    Hostetler, Jessica B.; Sharma, Sumana; Bartholdson, S. Josefin; Wright, Gavin J.; Fairhurst, Rick M.; Rayner, Julian C.

    2015-01-01

    Background A vaccine targeting Plasmodium vivax will be an essential component of any comprehensive malaria elimination program, but major gaps in our understanding of P. vivax biology, including the protein-protein interactions that mediate merozoite invasion of reticulocytes, hinder the search for candidate antigens. Only one ligand-receptor interaction has been identified, that between P. vivax Duffy Binding Protein (PvDBP) and the erythrocyte Duffy Antigen Receptor for Chemokines (DARC), and strain-specific immune responses to PvDBP make it a complex vaccine target. To broaden the repertoire of potential P. vivax merozoite-stage vaccine targets, we exploited a recent breakthrough in expressing full-length ectodomains of Plasmodium proteins in a functionally-active form in mammalian cells and initiated a large-scale study of P. vivax merozoite proteins that are potentially involved in reticulocyte binding and invasion. Methodology/Principal Findings We selected 39 P. vivax proteins that are predicted to localize to the merozoite surface or invasive secretory organelles, some of which show homology to P. falciparum vaccine candidates. Of these, we were able to express 37 full-length protein ectodomains in a mammalian expression system, which has been previously used to express P. falciparum invasion ligands such as PfRH5. To establish whether the expressed proteins were correctly folded, we assessed whether they were recognized by antibodies from Cambodian patients with acute vivax malaria. IgG from these samples showed at least a two-fold change in reactivity over naïve controls in 27 of 34 antigens tested, and the majority showed heat-labile IgG immunoreactivity, suggesting the presence of conformation-sensitive epitopes and native tertiary protein structures. Using a method specifically designed to detect low-affinity, extracellular protein-protein interactions, we confirmed a predicted interaction between P. vivax 6-cysteine proteins P12 and P41, further

  3. Development and evaluation of novel recombinant adenovirus-based vaccine candidates for infectious bronchitis virus and Mycoplasma gallisepticum in chickens.

    Science.gov (United States)

    Zhang, Dongchao; Long, Yuqing; Li, Meng; Gong, Jianfang; Li, Xiaohui; Lin, Jing; Meng, Jiali; Gao, Keke; Zhao, Ruili; Jin, Tianming

    2018-04-01

    Avian infectious bronchitis caused by the infectious bronchitis virus (IBV), and mycoplasmosis caused by Mycoplasma gallisepticum (MG) are two major respiratory diseases in chickens that have resulted in severe economic losses in the poultry industry. We constructed a recombinant adenovirus that simultaneously expresses the S1 spike glycoprotein of IBV and the TM-1 protein of MG (pBH-S1-TM-1-EGFP). For comparison, we constructed two recombinant adenoviruses (pBH-S1-EGFP and pBH-TM-1-EGFP) that express either the S1 spike glycoprotein or the TM-1 protein alone. The protective efficacy of these three vaccine constructs against challenge with IBV and/or MG was evaluated in specific pathogen free chickens. Groups of seven-day-old specific pathogen free chicks were immunized twice, two weeks apart, via the oculonasal route with the pBH-S1-TM-1-EGFP, pBH-S1-EGFP, or pBH-TM-1-EGFP vaccine candidates or the commercial attenuated infectious bronchitis vaccine strain H52 and MG vaccine strain F-36 (positive controls), and challenged with virulent IBV or MG two weeks later. Interestingly, by days 7 and 14 after the booster immunization, pBH-S1-TM-1-EGFP-induced antibody titre was significantly higher (P attenuated commercial IBV vaccine; however, there was no significant difference between the pBH-S1-TM-1-EGFP and attenuated commercial MG vaccine groups (P > 0.05). The clinical signs, the gross, and histopathological lesions scores of the adenovirus vaccine constructs were not significantly different from that of the attenuated commercial IBV or MG vaccines (positive controls) (P > 0.05). These results demonstrate the potential of the bivalent pBH-S1-TM-1-EGFP adenovirus construct as a combination vaccine against IB and mycoplasmosis.

  4. Improving the Th1 cellular efficacy of the lead Yersinia pestis rF1-V subunit vaccine using SA-4-1BBL as a novel adjuvant.

    Science.gov (United States)

    Dinc, Gunes; Pennington, Jarrod M; Yolcu, Esma S; Lawrenz, Matthew B; Shirwan, Haval

    2014-09-03

    The lead candidate plague subunit vaccine is the recombinant fusion protein rF1-V adjuvanted with alum. While alum generates Th2 regulated robust humoral responses, immune protection against Yersinia pestis has been shown to also involve Th1 driven cellular responses. Therefore, the rF1-V-based subunit vaccine may benefit from an adjuvant system that generates a mixed Th1 and humoral immune response. We herein assessed the efficacy of a novel SA-4-1BBL costimulatory molecule as a Th1 adjuvant to improve cellular responses generated by the rF1-V vaccine. SA-4-1BBL as a single adjuvant had better efficacy than alum in generating CD4(+) and CD8(+) T cells producing TNFα and IFNγ, signature cytokines for Th1 responses. The combination of SA-4-1BBL with alum further increased this Th1 response as compared with the individual adjuvants. Analysis of the humoral response revealed that SA-4-1BBL as a single adjuvant did not generate a significant Ab response against rF1-V, and SA-4-1BBL in combination with alum did not improve Ab titers. However, the combined adjuvants significantly increased the ratio of Th1 regulated IgG2c in C57BL/6 mice to the Th2 regulated IgG1. Finally, a single vaccination with rF1-V adjuvanted with SA-4-1BBL+alum had better protective efficacy than vaccines containing individual adjuvants. Taken together, these results demonstrate that SA-4-1BBL improves the protective efficacy of the alum adjuvanted lead rF1-V subunit vaccine by generating a more balanced Th1 cellular and humoral immune response. As such, this adjuvant platform may prove efficacious not only for the rF1-V vaccine but also against other infections that require both cellular and humoral immune responses for protection. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Quantitative PCR evaluation of cellular immune responses in Kenyan children vaccinated with a candidate malaria vaccine.

    Directory of Open Access Journals (Sweden)

    Jedidah Mwacharo

    2009-12-01

    Full Text Available The T-cell mediated immune response plays a central role in the control of malaria after natural infection or vaccination. There is increasing evidence that T-cell responses are heterogeneous and that both the quality of the immune response and the balance between pro-inflammatory and regulatory T-cells determines the outcome of an infection. As Malaria parasites have been shown to induce immunosuppressive responses to the parasite and non-related antigens this study examined T-cell mediated pro-inflammatory and regulatory immune responses induced by malaria vaccination in children in an endemic area to determine if these responses were associated with vaccine immunogenicity.Using real-time RT- PCR we profiled the expression of a panel of key markers of immunogenecity at different time points after vaccination with two viral vector vaccines expressing the malaria TRAP antigen (FP9-TRAP and MVA-TRAP or following rabies vaccination as a control.The vaccine induced modest levels of IFN-gamma mRNA one week after vaccination. There was also an increase in FoxP3 mRNA expression in both TRAP stimulated and media stimulated cells in the FFM ME-TRAP vaccine group; however, this may have been driven by natural exposure to parasite rather than by vaccination.Quantitative PCR is a useful method for evaluating vaccine induced cell mediated immune responses in frozen PBMC from children in a malaria endemic country. Future studies should seek to use vaccine vectors that increase the magnitude and quality of the IFN-gamma immune response in naturally exposed populations and should monitor the induction of a regulatory T cell response.

  6. Preclinical Development and Production of Virus-Like Particles As Vaccine Candidates for Hepatitis C

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    Makutiro Ghislain Masavuli

    2017-12-01

    Full Text Available Hepatitis C Virus (HCV infects 2% of the world’s population and is the leading cause of liver disease and liver transplantation. It poses a serious and growing worldwide public health problem that will only be partially addressed with the introduction of new antiviral therapies. However, these treatments will not prevent re-infection particularly in high risk populations. The introduction of a HCV vaccine has been predicted, using simulation models in a high risk population, to have a significant effect on reducing the incidence of HCV. A vaccine with 50 to 80% efficacy targeted to high-risk intravenous drug users could dramatically reduce HCV incidence in this population. Virus like particles (VLPs are composed of viral structural proteins which self-assemble into non-infectious particles that lack genetic material and resemble native viruses. Thus, VLPs represent a safe and highly immunogenic vaccine delivery platform able to induce potent adaptive immune responses. Currently, many VLP-based vaccines have entered clinical trials, while licensed VLP vaccines for hepatitis B virus (HBV and human papilloma virus (HPV have been in use for many years. The HCV core, E1 and E2 proteins can self-assemble into immunogenic VLPs while inclusion of HCV antigens into heterogenous (chimeric VLPs is also a promising approach. These VLPs are produced using different expression systems such as bacterial, yeast, mammalian, plant, or insect cells. Here, this paper will review HCV VLP-based vaccines and their immunogenicity in animal models as well as the different expression systems used in their production.

  7. Immunogenicity of a virosomally-formulated Plasmodium falciparum GLURP-MSP3 chimeric protein-based malaria vaccine candidate in comparison to adjuvanted formulations

    DEFF Research Database (Denmark)

    Tamborrini, Marco; Stoffel, Sabine A; Westerfeld, Nicole

    2011-01-01

    In clinical trials, immunopotentiating reconstituted influenza virosomes (IRIVs) have shown great potential as a versatile antigen delivery platform for synthetic peptides derived from Plasmodium falciparum antigens. This study describes the immunogenicity of a virosomally-formulated recombinant ...... fusion protein comprising domains of the two malaria vaccine candidate antigens MSP3 and GLURP....

  8. Identification of potential new protein vaccine candidates through pan-surfomic analysis of pneumococcal clinical isolates from adults.

    Directory of Open Access Journals (Sweden)

    Alfonso Olaya-Abril

    Full Text Available Purified polysaccharide and conjugate vaccines are widely used for preventing infections in adults and in children against the Gram-positive bacterium Streptococcus pneumoniae, a pathogen responsible for high morbidity and mortality rates, especially in developing countries. However, these polysaccharide-based vaccines have some important limitations, such as being serotype-dependent, being subjected to losing efficacy because of serotype replacement and high manufacturing complexity and cost. It is expected that protein-based vaccines will overcome these issues by conferring a broad coverage independent of serotype and lowering production costs. In this study, we have applied the "shaving" proteomic approach, consisting of the LC/MS/MS analysis of peptides generated by protease treatment of live cells, to a collection of 16 pneumococcal clinical isolates from adults, representing the most prevalent strains circulating in Spain during the last years. The set of unique proteins identified in all the isolates, called "pan-surfome", consisted of 254 proteins, which included most of the protective protein antigens reported so far. In search of new candidates with vaccine potential, we identified 32 that were present in at least 50% of the clinical isolates analyzed. We selected four of them (Spr0012, Spr0328, Spr0561 and SP670_2141, whose protection capacity has not yet been tested, for assaying immunogenicity in human sera. All of them induced the production of IgM antibodies in infected patients, thus indicating that they could enter the pipeline for vaccine studies. The pan-surfomic approach shows its utility in the discovery of new proteins that can elicit protection against infectious microorganisms.

  9. A 52 Kilodalton Protein Vaccine Candidate for Francisella tularensis

    Science.gov (United States)

    2004-12-01

    du vaccin vivant F. tularensis (LVS). Soixante pourcent (60%) des souris vaccindes ont survdcu la dose ltale multiple alors que toutes les souris non...le lysat des cellules de cultures vivantes du vaccin vivant F. tularensis. Plusieurs composants de Francisella tularensis ont dt6 identifids par cet...antiserum. Le s6rum de souris provenant de souris vaccin6es avec F. tularensis non- vivant n’a pas identifid ces composants. A partir de ces prot6ines

  10. The recent progress in RSV vaccine technology.

    Science.gov (United States)

    Fretzayas, Andrew; Papadopoulou, Anna; Kotzia, Doxa; Moustaki, Maria

    2012-12-01

    The most effective way to control RSV infection would be the development of an expedient and safe vaccine. Subunit vaccines, live attenuated RSV vaccines, plasmid DNA vaccines have been tested either in human or in mouse models without reaching the ultimate goal of efficacy and safety, at least in humans. Viruses such as adenovirus, sendai virus, measles virus were also used as vectors for the generation of RSV vaccines with promising results in animal models. Recent patents describe new techniques for the generation of candidate vaccines. These patents include virus like particles as vaccine platforms, recombinant RSVs or modified RSV F protein as component of the vaccine. Despite the number of the candidate vaccines, the new RSV vaccines should overcome many obstacles before being established as effective vaccines for the control of RSV infections especially for the young infants who are more susceptible to the virus.

  11. Attenuation and efficacy of human parainfluenza virus type 1 (HPIV1 vaccine candidates containing stabilized mutations in the P/C and L genes

    Directory of Open Access Journals (Sweden)

    Skiadopoulos Mario H

    2007-07-01

    Full Text Available Abstract Background Two recombinant, live attenuated human parainfluenza virus type 1 (rHPIV1 mutant viruses have been developed, using a reverse genetics system, for evaluation as potential intranasal vaccine candidates. These rHPIV1 vaccine candidates have two non-temperature sensitive (non-ts attenuating (att mutations primarily in the P/C gene, namely CR84GHNT553A (two point mutations used together as a set and CΔ170 (a short deletion mutation, and two ts att mutations in the L gene, namely LY942A (a point mutation, and LΔ1710–11 (a short deletion, the last of which has not been previously described. The latter three mutations were specifically designed for increased genetic and phenotypic stability. These mutations were evaluated on the HPIV1 backbone, both individually and in combination, for attenuation, immunogenicity, and protective efficacy in African green monkeys (AGMs. Results The rHPIV1 mutant bearing the novel LΔ1710–11 mutation was highly ts and attenuated in AGMs and was immunogenic and efficacious against HPIV1 wt challenge. The rHPIV1-CR84G/Δ170HNT553ALY942A and rHPIV1-CR84G/Δ170HNT553ALΔ1710–11 vaccine candidates were highly ts, with shut-off temperatures of 38°C and 35°C, respectively, and were highly attenuated in AGMs. Immunization with rHPIV1-CR84G/Δ170HNT553ALY942A protected against HPIV1 wt challenge in both the upper and lower respiratory tracts. In contrast, rHPIV1-CR84G/Δ170HNT553ALΔ1710–11 was not protective in AGMs due to over-attenuation, but it is expected to replicate more efficiently and be more immunogenic in the natural human host. Conclusion The rHPIV1-CR84G/Δ170HNT553ALY942A and rHPIV1-CR84G/Δ170HNT553ALΔ1710–11 vaccine candidates are clearly highly attenuated in AGMs and clinical trials are planned to address safety and immunogenicity in humans.

  12. Newer Vaccines against Mosquito-borne Diseases.

    Science.gov (United States)

    Aggarwal, Anju; Garg, Neha

    2018-02-01

    Mosquitos are responsible for a number of protozoal and viral diseases. Malaria, dengue, Japanese encephalitis (JE) and chikungunya epidemics occur commonly all over the world, leading to marked mortality and morbidity in children. Zika, Yellow fever and West Nile fever are others requiring prevention. Environmental control and mosquito bite prevention are useful in decreasing the burden of disease but vaccination has been found to be most cost-effective and is the need of the hour. RTS,S/AS01 vaccine is the first malaria vaccine being licensed for use against P. falciparum malaria. Dengvaxia (CYD-TDV) against dengue was licensed first in Mexico in 2015. A Vero-cell derived, inactivated and alum-adjuvanted JE vaccine based on the SA14-14-2 strain was approved in 2009 in North America, Australia and various European countries. It can be used from 2 mo of age. In India, immunization is carried out in endemic regions at 1 y of age. Another inactivated Vero-cell culture derived Kolar strain, 821564XY, JE vaccine is being used in India. Candidate vaccines against dengue, chikungunya and West Nile fever are been discussed. A continued research and development of new vaccines are required for controlling these mosquito-borne diseases.

  13. High-yield production of a stable Vero cell-based vaccine candidate against the highly pathogenic avian influenza virus H5N1

    International Nuclear Information System (INIS)

    Zhou, Fangye; Zhou, Jian; Ma, Lei; Song, Shaohui; Zhang, Xinwen; Li, Weidong; Jiang, Shude; Wang, Yue; Liao, Guoyang

    2012-01-01

    Highlights: ► Vero cell-based HPAI H5N1 vaccine with stable high yield. ► Stable high yield derived from the YNVa H3N2 backbone. ► H5N1/YNVa has a similar safety and immunogenicity to H5N1delta. -- Abstract: Highly pathogenic avian influenza (HPAI) viruses pose a global pandemic threat, for which rapid large-scale vaccine production technology is critical for prevention and control. Because chickens are highly susceptible to HPAI viruses, the supply of chicken embryos for vaccine production might be depleted during a virus outbreak. Therefore, developing HPAI virus vaccines using other technologies is critical. Meeting vaccine demand using the Vero cell-based fermentation process has been hindered by low stability and yield. In this study, a Vero cell-based HPAI H5N1 vaccine candidate (H5N1/YNVa) with stable high yield was achieved by reassortment of the Vero-adapted (Va) high growth A/Yunnan/1/2005(H3N2) (YNVa) virus with the A/Anhui/1/2005(H5N1) attenuated influenza vaccine strain (H5N1delta) using the 6/2 method. The reassorted H5N1/YNVa vaccine maintained a high hemagglutination (HA) titer of 1024. Furthermore, H5N1/YNVa displayed low pathogenicity and uniform immunogenicity compared to that of the parent virus.

  14. Mechanism of protection induced by group A Streptococcus vaccine candidate J8-DT: contribution of B and T-cells towards protection.

    Directory of Open Access Journals (Sweden)

    Manisha Pandey

    Full Text Available Vaccination with J8-DT, a leading GAS vaccine candidate, results in protective immunity in mice. Analysis of immunologic correlates of protection indicated a role of J8-specific antibodies that were induced post-immunization. In the present study, several independent experimental approaches were employed to investigate the protective immunological mechanisms involved in J8-DT-mediated immunity. These approaches included the passive transfer of mouse or rabbit immune serum/antibodies in addition to selective depletion of T-cell subsets prior to bacterial challenge. Passive transfer of J8-DT antiserum/antibodies from mice and rabbits conferred significant resistance against challenge to mice. To exclude the possibility of involvement of other host immune factors, the studies were repeated in SCID mice, which highlighted the need for an ongoing immune response for long-lived protection. Depletion of CD4(+ and CD8(+ T-cell subsets confirmed that an active de novo immune response, involving CD4(+ T-helper cells, is required for continued synthesis of antibodies resulting in protection against GAS infection. Taken together these results indicate an involvement of CD4(+ T-cells in J8-DT-mediated protection possibly via an ability to maintain antibody levels. These results have considerable relevance to the development of a broad spectrum passive immunotherapy for GAS disease.

  15. Enhanced mucosal immune responses induced by a combined candidate mucosal vaccine based on Hepatitis A virus and Hepatitis E virus structural proteins linked to tuftsin.

    Science.gov (United States)

    Gao, Yan; Su, Qiudong; Yi, Yao; Jia, Zhiyuan; Wang, Hao; Lu, Xuexin; Qiu, Feng; Bi, Shengli

    2015-01-01

    Hepatitis A virus (HAV) and Hepatitis E virus (HEV) are the most common causes of infectious hepatitis. These viruses are spread largely by the fecal-oral route and lead to clinically important disease in developing countries. To evaluate the potential of targeting hepatitis A and E infection simultaneously, a combined mucosal candidate vaccine was developed with the partial open reading frame 2 (ORF2) sequence (aa 368-607) of HEV (HE-ORF2) and partial virus protein 1 (VP1) sequence (aa 1-198) of HAV (HA-VP1), which included the viral neutralization epitopes. Tuftsin is an immunostimulatory peptide which can enhance the immunogenicity of a protein by targeting it to macrophages and dendritic cells. Here, we developed a novel combined protein vaccine by conjugating tuftsin to HE-ORF2 and HA-VP1 and used synthetic CpG oligodeoxynucleotides (ODNs) as the adjuvant. Subsequent experiments in BALB/c mice demonstrated that tuftsin enhanced the serum-specific IgG and IgA antibodies against HEV and HAV at the intestinal, vaginal and pulmonary interface when delivered intranasally. Moreover, mice from the intranasally immunized tuftsin group (HE-ORF2-tuftsin + HA-VP1-tuftsin + CpG) showed higher levels of IFN-γ-secreting splenocytes (Th1 response) and ratio of CD4+/CD8+ T cells than those of the no-tuftsin group (HE-ORF2 + HA-VP1 + CpG). Thus, the tuftsin group generated stronger humoral and cellular immune responses compared with the no-tuftsin group. Moreover, enhanced responses to the combined protein vaccine were obtained by intranasal immunization compared with intramuscular injection. By integrating HE-ORF2, HA-VP1 and tuftsin in a vaccine, this study validated an important concept for further development of a combined mucosal vaccine against hepatitis A and E infection.

  16. Prospects and perspectives for development of a vaccine against herpes simplex virus infections.

    Science.gov (United States)

    McAllister, Shane C; Schleiss, Mark R

    2014-11-01

    Herpes simplex viruses 1 and 2 are human pathogens that lead to significant morbidity and mortality in certain clinical settings. The development of effective antiviral medications, however, has had little discernible impact on the epidemiology of these pathogens, largely because the majority of infections are clinically silent. Decades of work have gone into various candidate HSV vaccines, but to date none has demonstrated sufficient efficacy to warrant licensure. This review examines developments in HSV immunology and vaccine development published since 2010, and assesses the prospects for improved immunization strategies that may result in an effective, licensed vaccine in the near future.

  17. Assessment of Lactobacillus gasseri as a Candidate Oral Vaccine Vector ▿

    Science.gov (United States)

    Stoeker, Laura; Nordone, Shila; Gunderson, Sara; Zhang, Lin; Kajikawa, Akinobu; LaVoy, Alora; Miller, Michael; Klaenhammer, Todd R.; Dean, Gregg A.

    2011-01-01

    Lactobacillus species are commensal bacteria that have long been recognized as probiotic microbes and are generally regarded as safe (GRAS) for human consumption. We have investigated the use of L. gasseri as a vaccine vector for oral immunization against mucosal pathogens. Recent research has shown that the immune response to different lactobacilli can vary widely depending on the species or subspecies of Lactobacillus being studied. While some lactobacilli seem to induce oral tolerance, others induce an adaptive immune response. This study characterized the systemic and mucosal immune response to wild-type and genetically modified L. gasseri. L. gasseri primarily activates TLR2/6, with additional activation through the TLR2 homodimer. To expand the Toll-like receptor (TLR) activation profile of L. gasseri and the immunogenicity of the vector, a plasmid containing fliC, the gene encoding bacterial flagellin, was introduced which resulted in the strong activation of TLR5. The treatment of human myeloid dendritic cells with recombinant lactobacilli expressing flagellin triggered phenotypic maturation and the release of proinflammatory cytokines. In contrast, bacterial treatment also resulted in a statistically significant increase in IL-10 production. In vivo studies established that treatment with L. gasseri led to a diversification of B-cell populations in the lamina propria of the murine colon. Furthermore, treatment with genetically modified L. gasseri led to a significant decrease in the percentage of FoxP3+ colonic lymphocytes. Taken together, these data clarify the interaction of L. gasseri with the host immune system and support further investigation of the in vivo immunogenicity of L. gasseri expressing both flagellin and candidate vaccine antigens. PMID:21900526

  18. Vaccination against Salmonella Infection: the Mucosal Way.

    Science.gov (United States)

    Gayet, Rémi; Bioley, Gilles; Rochereau, Nicolas; Paul, Stéphane; Corthésy, Blaise

    2017-09-01

    Salmonella enterica subspecies enterica includes several serovars infecting both humans and other animals and leading to typhoid fever or gastroenteritis. The high prevalence of associated morbidity and mortality, together with an increased emergence of multidrug-resistant strains, is a current global health issue that has prompted the development of vaccination strategies that confer protection against most serovars. Currently available systemic vaccine approaches have major limitations, including a reduced effectiveness in young children and a lack of cross-protection among different strains. Having studied host-pathogen interactions, microbiologists and immunologists argue in favor of topical gastrointestinal administration for improvement in vaccine efficacy. Here, recent advances in this field are summarized, including mechanisms of bacterial uptake at the intestinal epithelium, the assessment of protective host immunity, and improved animal models that closely mimic infection in humans. The pros and cons of existing vaccines are presented, along with recent progress made with novel formulations. Finally, new candidate antigens and their relevance in the refined design of anti- Salmonella vaccines are discussed, along with antigen vectorization strategies such as nanoparticles or secretory immunoglobulins, with a focus on potentiating mucosal vaccine efficacy. Copyright © 2017 American Society for Microbiology.

  19. A phase I randomized clinical trial of candidate human immunodeficiency virus type 1 vaccine MVA.HIVA administered to Gambian infants.

    Directory of Open Access Journals (Sweden)

    Muhammed O Afolabi

    Full Text Available A vaccine to decrease transmission of human immunodeficiency virus type 1 (HIV-1 during breast-feeding would complement efforts to eliminate infant HIV-1 infection by antiretroviral therapy. Relative to adults, infants have distinct immune development, potentially high-risk of transmission when exposed to HIV-1 and rapid progression to AIDS when infected. To date, there have been only three published HIV-1 vaccine trials in infants.We conducted a randomized phase I clinical trial PedVacc 001 assessing the feasibility, safety and immunogenicity of a single dose of candidate vaccine MVA.HIVA administered intramuscularly to 20-week-old infants born to HIV-1-negative mothers in The Gambia.Infants were followed to 9 months of age with assessment of safety, immunogenicity and interference with Expanded Program on Immunization (EPI vaccines. The trial is the first stage of developing more complex prime-boost vaccination strategies against breast milk transmission of HIV-1.From March to October 2010, 48 infants (24 vaccine and 24 no-treatment were enrolled with 100% retention. The MVA.HIVA vaccine was safe with no difference in adverse events between vaccinees and untreated infants. Two vaccine recipients (9% and no controls had positive ex vivo interferon-γ ELISPOT assay responses. Antibody levels elicited to the EPI vaccines, which included diphtheria, tetanus, whole-cell pertussis, hepatitis B virus, Haemophilus influenzae type b and oral poliovirus, reached protective levels for the vast majority and were similar between the two arms.A single low-dose of MVA.HIVA administered to 20-week-old infants in The Gambia was found to be safe and without interference with the induction of protective antibody levels by EPI vaccines, but did not alone induce sufficient HIV-1-specific responses. These data support the use of MVA carrying other transgenes as a boosting vector within more complex prime-boost vaccine strategies against transmission of HIV-1 and

  20. Reverse Vaccinology: An Approach for Identifying Leptospiral Vaccine Candidates

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    Odir A. Dellagostin

    2017-01-01

    Full Text Available Leptospirosis is a major public health problem with an incidence of over one million human cases each year. It is a globally distributed, zoonotic disease and is associated with significant economic losses in farm animals. Leptospirosis is caused by pathogenic Leptospira spp. that can infect a wide range of domestic and wild animals. Given the inability to control the cycle of transmission among animals and humans, there is an urgent demand for a new vaccine. Inactivated whole-cell vaccines (bacterins are routinely used in livestock and domestic animals, however, protection is serovar-restricted and short-term only. To overcome these limitations, efforts have focused on the development of recombinant vaccines, with partial success. Reverse vaccinology (RV has been successfully applied to many infectious diseases. A growing number of leptospiral genome sequences are now available in public databases, providing an opportunity to search for prospective vaccine antigens using RV. Several promising leptospiral antigens were identified using this approach, although only a few have been characterized and evaluated in animal models. In this review, we summarize the use of RV for leptospirosis and discuss the need for potential improvements for the successful development of a new vaccine towards reducing the burden of human and animal leptospirosis.

  1. APPROACHING THE TARGET: THE PATH TOWARDS AN EFFECTIVE MALARIA VACCINE

    Directory of Open Access Journals (Sweden)

    Alberto L. García-Basteiro

    2012-01-01

    Full Text Available Eliciting an effective malaria vaccine has been the goal of the scientific community for many years. A malaria vaccine, added to existing tools and strategies, would further prevent and decrease the unacceptable malaria morbidity and mortality burden. Great progress has been made over the last decade, with some vaccine candidates in the clinical phases of development. The RTS,S malaria vaccine candidate, based on a recombinant P. falciparum protein, is the most advanced of such candidates, currently undergoing a large phase III trial. RTS,S has consistently shown an efficacy of around 50% against the first clinical episode of malaria, with protection in some cases extending up to 4 years of duration. Thus, it is hoped that this candidate vaccine will eventually become the first licensed malaria vaccine. This first vaccine against a human parasite is a groundbreaking achievement, but improved malaria vaccines conferring higher protection will be needed if the aspiration of malaria eradication is to be achieved

  2. High-yield production of a stable Vero cell-based vaccine candidate against the highly pathogenic avian influenza virus H5N1

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Fangye; Zhou, Jian; Ma, Lei; Song, Shaohui; Zhang, Xinwen; Li, Weidong; Jiang, Shude [No. 5, Department of Bioproducts, Institute of Medical Biology, Chinese Academy of Medical Science and Pecking Union Medical College, Jiaoling Avenue 935, Kunming, Yunnan Province 650102, People' s Republic of China (China); Wang, Yue [National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Yingxin Lane 100, Xicheng District, Beijing 100052, People' s Republic of China (China); Liao, Guoyang [No. 5, Department of Bioproducts, Institute of Medical Biology, Chinese Academy of Medical Science and Pecking Union Medical College, Jiaoling Avenue 935, Kunming, Yunnan Province 650102, People' s Republic of China (China)

    2012-05-18

    Highlights: Black-Right-Pointing-Pointer Vero cell-based HPAI H5N1 vaccine with stable high yield. Black-Right-Pointing-Pointer Stable high yield derived from the YNVa H3N2 backbone. Black-Right-Pointing-Pointer H5N1/YNVa has a similar safety and immunogenicity to H5N1delta. -- Abstract: Highly pathogenic avian influenza (HPAI) viruses pose a global pandemic threat, for which rapid large-scale vaccine production technology is critical for prevention and control. Because chickens are highly susceptible to HPAI viruses, the supply of chicken embryos for vaccine production might be depleted during a virus outbreak. Therefore, developing HPAI virus vaccines using other technologies is critical. Meeting vaccine demand using the Vero cell-based fermentation process has been hindered by low stability and yield. In this study, a Vero cell-based HPAI H5N1 vaccine candidate (H5N1/YNVa) with stable high yield was achieved by reassortment of the Vero-adapted (Va) high growth A/Yunnan/1/2005(H3N2) (YNVa) virus with the A/Anhui/1/2005(H5N1) attenuated influenza vaccine strain (H5N1delta) using the 6/2 method. The reassorted H5N1/YNVa vaccine maintained a high hemagglutination (HA) titer of 1024. Furthermore, H5N1/YNVa displayed low pathogenicity and uniform immunogenicity compared to that of the parent virus.

  3. The clinical development process for a novel preventive vaccine: An overview

    Directory of Open Access Journals (Sweden)

    K Singh

    2016-01-01

    Full Text Available Each novel vaccine candidate needs to be evaluated for safety, immunogenicity, and protective efficacy in humans before it is licensed for use. After initial safety evaluation in healthy adults, each vaccine candidate follows a unique development path. This article on clinical development gives an overview on the development path based on the expectations of various guidelines issued by the World Health Organization (WHO, the European Medicines Agency (EMA, and the United States Food and Drug Administration (USFDA. The manuscript describes the objectives, study populations, study designs, study site, and outcome(s of each phase (Phase I-III of a clinical trial. Examples from the clinical development of a malaria vaccine candidate, a rotavirus vaccine, and two vaccines approved for human papillomavirus (HPV have also been discussed. The article also tabulates relevant guidelines, which can be referred to while drafting the development path of a novel vaccine candidate.

  4. Optimizing expression of the pregnancy malaria vaccine candidate, VAR2CSA in Pichia pastoris.

    Science.gov (United States)

    Avril, Marion; Hathaway, Marianne J; Cartwright, Megan M; Gose, Severin O; Narum, David L; Smith, Joseph D

    2009-06-29

    VAR2CSA is the main candidate for a vaccine against pregnancy-associated malaria, but vaccine development is complicated by the large size and complex disulfide bonding pattern of the protein. Recent X-ray crystallographic information suggests that domain boundaries of VAR2CSA Duffy binding-like (DBL) domains may be larger than previously predicted and include two additional cysteine residues. This study investigated whether longer constructs would improve VAR2CSA recombinant protein secretion from Pichia pastoris and if domain boundaries were applicable across different VAR2CSA alleles. VAR2CSA sequences were bioinformatically analysed to identify the predicted C11 and C12 cysteine residues at the C-termini of DBL domains and revised N- and C-termimal domain boundaries were predicted in VAR2CSA. Multiple construct boundaries were systematically evaluated for protein secretion in P. pastoris and secreted proteins were tested as immunogens. From a total of 42 different VAR2CSA constructs, 15 proteins (36%) were secreted. Longer construct boundaries, including the predicted C11 and C12 cysteine residues, generally improved expression of poorly or non-secreted domains and permitted expression of all six VAR2CSA DBL domains. However, protein secretion was still highly empiric and affected by subtle differences in domain boundaries and allelic variation between VAR2CSA sequences. Eleven of the secreted proteins were used to immunize rabbits. Antibodies reacted with CSA-binding infected erythrocytes, indicating that P. pastoris recombinant proteins possessed native protein epitopes. These findings strengthen emerging data for a revision of DBL domain boundaries in var-encoded proteins and may facilitate pregnancy malaria vaccine development.

  5. Optimizing expression of the pregnancy malaria vaccine candidate, VAR2CSA in Pichia pastoris

    Directory of Open Access Journals (Sweden)

    Narum David L

    2009-06-01

    Full Text Available Abstract Background VAR2CSA is the main candidate for a vaccine against pregnancy-associated malaria, but vaccine development is complicated by the large size and complex disulfide bonding pattern of the protein. Recent X-ray crystallographic information suggests that domain boundaries of VAR2CSA Duffy binding-like (DBL domains may be larger than previously predicted and include two additional cysteine residues. This study investigated whether longer constructs would improve VAR2CSA recombinant protein secretion from Pichia pastoris and if domain boundaries were applicable across different VAR2CSA alleles. Methods VAR2CSA sequences were bioinformatically analysed to identify the predicted C11 and C12 cysteine residues at the C-termini of DBL domains and revised N- and C-termimal domain boundaries were predicted in VAR2CSA. Multiple construct boundaries were systematically evaluated for protein secretion in P. pastoris and secreted proteins were tested as immunogens. Results From a total of 42 different VAR2CSA constructs, 15 proteins (36% were secreted. Longer construct boundaries, including the predicted C11 and C12 cysteine residues, generally improved expression of poorly or non-secreted domains and permitted expression of all six VAR2CSA DBL domains. However, protein secretion was still highly empiric and affected by subtle differences in domain boundaries and allelic variation between VAR2CSA sequences. Eleven of the secreted proteins were used to immunize rabbits. Antibodies reacted with CSA-binding infected erythrocytes, indicating that P. pastoris recombinant proteins possessed native protein epitopes. Conclusion These findings strengthen emerging data for a revision of DBL domain boundaries in var-encoded proteins and may facilitate pregnancy malaria vaccine development.

  6. Drug efficiency: a new concept to guide lead optimization programs towards the selection of better clinical candidates.

    Science.gov (United States)

    Braggio, Simone; Montanari, Dino; Rossi, Tino; Ratti, Emiliangelo

    2010-07-01

    As a result of their wide acceptance and conceptual simplicity, drug-like concepts are having a major influence on the drug discovery process, particularly in the selection of the 'optimal' absorption, distribution, metabolism, excretion and toxicity and physicochemical parameters space. While they have an undisputable value when assessing the potential of lead series or in evaluating inherent risk of a portfolio of drug candidates, they result much less useful in weighing up compounds for the selection of the best potential clinical candidate. We introduce the concept of drug efficiency as a new tool both to guide the drug discovery program teams during the lead optimization phase and to better assess the developability potential of a drug candidate.

  7. Leptospirosis vaccines: Past, present, and future

    Directory of Open Access Journals (Sweden)

    Koizumi N

    2005-01-01

    Full Text Available It is well known that Leptospira vaccine prevents the disease. However specificity for serovars limits the efficacy of killed whole cell vaccines. Leptospiral antigens that induce cross-protective immunity to the various serovars are sought as new vaccine candidates. In this paper, we have summarized both past and current findings about leptospiral antigens that are conserved among pathogenic leptospires and that induce protective immunity in animal models. The full-length genome sequences of two Leptospira strains have been published and reverse vaccinology has been used to identify leptospiral vaccine candidates. Although humoral immunity is thought to be dominant in protection from leptospiral infection, a role for cell-mediated immunity is now being explored.

  8. Technical Transformation of Biodefense Vaccines

    Science.gov (United States)

    Lu, Shan; Wang, Shixia

    2013-01-01

    Biodefense vaccines are developed against a diverse group of pathogens. Vaccines were developed for some of these pathogens a long time ago but they are facing new challenges to move beyond the old manufacturing technologies. New vaccines to be developed against other pathogens have to determine whether to follow traditional vaccination strategies or to seek new approaches. Advances in basic immunology and recombinant DNA technology have fundamentally transformed the process of formulating a vaccine concept, optimizing protective antigens, and selecting the most effective vaccine delivery approach for candidate biodefense vaccines. PMID:19837293

  9. Vaccines in a hurry.

    Science.gov (United States)

    Søborg, Christian; Mølbak, Kåre; Doherty, T Mark; Ulleryd, Peter; Brooks, Tim; Coenen, Claudine; van der Zeijst, Ben

    2009-05-26

    Preparing populations for health threats, including threats from new or re-emerging infectious diseases is recognised as an important public health priority. The development, production and application of emergency vaccinations are the important measures against such threats. Vaccines are cost-effective tools to prevent disease, and emergency vaccines may be the only means to prevent a true disaster for global society in the event of a new pandemic with potential to cause morbidity and mortality comparable to the Spanish flu, the polio epidemics in the 1950s, or the SARS outbreak in 2003 if its spread had not been contained in time. Given the early recognition of a new threat, and given the advances of biotechnology, vaccinology and information systems, it is not an unrealistic goal to have promising prototype vaccine candidates available in a short time span following the identification of a new infectious agent; this is based on the assumption that the emerging infection is followed by natural immunity. However, major bottlenecks for the deployment of emergency vaccine are lack of established systems for fast-track regulatory approval of such candidates and limited international vaccine production capacity. In the present discussion paper, we propose mechanisms to facilitate development of emergency vaccines in Europe by focusing on public-private scientific partnerships, fast-track approval of emergency vaccine by regulatory agencies and proposing incentives for emergency vaccine production in private vaccine companies.

  10. Impact and cost-effectiveness of rotavirus vaccination in Bangladesh.

    Science.gov (United States)

    Pecenka, Clint; Parashar, Umesh; Tate, Jacqueline E; Khan, Jahangir A M; Groman, Devin; Chacko, Stephen; Shamsuzzaman, Md; Clark, Andrew; Atherly, Deborah

    2017-07-13

    Diarrheal disease is a leading cause of child mortality globally, and rotavirus is responsible for more than a third of those deaths. Despite substantial decreases, the number of rotavirus deaths in children under five was 215,000 per year in 2013. Of these deaths, approximately 41% occurred in Asia and 3% of those in Bangladesh. While Bangladesh has yet to introduce rotavirus vaccination, the country applied for Gavi support and plans to introduce it in 2018. This analysis evaluates the impact and cost-effectiveness of rotavirus vaccination in Bangladesh and provides estimates of the costs of the vaccination program to help inform decision-makers and international partners. This analysis used Pan American Health Organization's TRIVAC model (version 2.0) to examine nationwide introduction of two-dose rotavirus vaccination in 2017, compared to no vaccination. Three mortality scenarios (low, high, and midpoint) were assessed. Benefits and costs were examined from the societal perspective over ten successive birth cohorts with a 3% discount rate. Model inputs were locally acquired and complemented by internationally validated estimates. Over ten years, rotavirus vaccination would prevent 4000 deaths, nearly 500,000 hospitalizations and 3 million outpatient visits in the base scenario. With a Gavi subsidy, cost/disability adjusted life year (DALY) ratios ranged from $58/DALY to $142/DALY averted. Without a Gavi subsidy and a vaccine price of $2.19 per dose, cost/DALY ratios ranged from $615/DALY to $1514/DALY averted. The discounted cost per DALY averted was less than the GDP per capita for nearly all scenarios considered, indicating that a routine rotavirus vaccination program is highly likely to be cost-effective. Even in a low mortality setting with no Gavi subsidy, rotavirus vaccination would be cost-effective. These estimates exclude the herd immunity benefits of vaccination, so represent a conservative estimate of the cost-effectiveness of rotavirus vaccination

  11. Novel structurally designed vaccine for S. aureus α-hemolysin: protection against bacteremia and pneumonia.

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    Rajan P Adhikari

    Full Text Available Staphylococcus aureus (S. aureus is a human pathogen associated with skin and soft tissue infections (SSTI and life threatening sepsis and pneumonia. Efforts to develop effective vaccines against S. aureus have been largely unsuccessful, in part due to the variety of virulence factors produced by this organism. S. aureus alpha-hemolysin (Hla is a pore-forming toxin expressed by most S. aureus strains and reported to play a key role in the pathogenesis of SSTI and pneumonia. Here we report a novel recombinant subunit vaccine candidate for Hla, rationally designed based on the heptameric crystal structure. This vaccine candidate, denoted AT-62aa, was tested in pneumonia and bacteremia infection models using S. aureus strain Newman and the pandemic strain USA300 (LAC. Significant protection from lethal bacteremia/sepsis and pneumonia was observed upon vaccination with AT-62aa along with a Glucopyranosyl Lipid Adjuvant-Stable Emulsion (GLA-SE that is currently in clinical trials. Passive transfer of rabbit immunoglobulin against AT-62aa (AT62-IgG protected mice against intraperitoneal and intranasal challenge with USA300 and produced significant reduction in bacterial burden in blood, spleen, kidney, and lungs. Our Hla-based vaccine is the first to be reported to reduce bacterial dissemination and to provide protection in a sepsis model of S. aureus infection. AT62-IgG and sera from vaccinated mice effectively neutralized the toxin in vitro and AT62-IgG inhibited the formation of Hla heptamers, suggesting antibody-mediated neutralization as the primary mechanism of action. This remarkable efficacy makes this Hla-based vaccine a prime candidate for inclusion in future multivalent S. aureus vaccine. Furthermore, identification of protective epitopes within AT-62aa could lead to novel immunotherapy for S. aureus infection.

  12. Protection efficacy of the Brucella abortus ghost vaccine candidate lysed by the N-terminal 24-amino acid fragment (GI24) of the 36-amino acid peptide PMAP-36 (porcine myeloid antimicrobial peptide 36) in murine models.

    Science.gov (United States)

    Kwon, Ae Jeong; Moon, Ja Young; Kim, Won Kyong; Kim, Suk; Hur, Jin

    2016-11-01

    Brucella abortus cells were lysed by the N-terminal 24-amino acid fragment (GI24) of the 36-amino acid peptide PMAP-36 (porcine myeloid antimicrobial peptide 36). Next, the protection efficacy of the lysed fragment as a vaccine candidate was evaluated. Group A mice were immunized with sterile PBS, group B mice were intraperitoneally (ip) immunized with 3 × 10 8 colony-forming units (CFUs) of B. abortus strain RB51, group C mice were immunized ip with 3 × 10 8 cells of the B. abortus vaccine candidate, and group D mice were orally immunized with 3 × 10 9 cells of the B. abortus vaccine candidate. Brucella lipopolysaccharide (LPS)-specific serum IgG titers were considerably higher in groups C and D than in group A. The levels of interleukin (IL)-4, IL-10, tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) were significantly higher in groups B-D than in group A. After an ip challenge with B. abortus 544, only group C mice showed a significant level of protection as compared to group A. Overall, these results show that ip immunization with a vaccine candidate lysed by GI24 can effectively protect mice from systemic infection with virulent B. abortus.

  13. Randomized controlled trial of RTS,S/AS02D and RTS,S/AS01E malaria candidate vaccines given according to different schedules in Ghanaian children.

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    Seth Owusu-Agyei

    2009-10-01

    Full Text Available The target delivery channel of RTS,S candidate malaria vaccines in malaria-endemic countries in Africa is the World Health Organisation Expanded Program on Immunization. As an Adjuvant System, age de-escalation and schedule selection step, this study assessed 3 schedules of RTS,S/AS01(E and RTS,S/AS02(D in infants and young children 5-17 months of age in Ghana.A Phase II, partially-blind randomized controlled study (blind to vaccine, not to schedule, of 19 months duration was conducted in two (2 centres in Ghana between August 2006 and May 2008. Subjects were allocated randomly (1:1:1:1:1:1 to one of six study groups at each study site, each defining which vaccine should be given and by which schedule (0,1-, 0,1,2- or 0,1,7-months. For the 0,1,2-month schedule participants received RTS,S/AS01(E or rabies vaccine at one center and RTS,S/AS01(E or RTS,S/AS02(D at the other. For the other schedules at both study sites, they received RTS,S/AS01(E or RTS,S/AS02(D. The primary outcome measure was the occurrence of serious adverse events until 10 months post dose 1.The number of serious adverse events reported across groups was balanced. One child had a simple febrile convulsion, which evolved favourably without sequelae, considered to be related to RTS,S/AS01(E vaccination. Low grade reactions occurred slightly more frequently in recipients of RTS,S/AS than rabies vaccines; grade 3 reactions were infrequent. Less local reactogenicity occurred with RTS,S/AS01(E than RTS,S/AS02(D. Both candidate vaccines were highly immunogenic for anti-circumsporozoite and anti-Hepatitis B Virus surface antigen antibodies. Recipients of RTS,S/AS01(E compared to RTS,S/AS02(D had higher peak anti-circumsporozoite antibody responses for all 3 schedules. Three dose schedules were more immunogenic than 2 dose schedules. Area under the curve analyses for anti-circumsporozoite antibodies were comparable between the 0,1,2- and 0,1,7-month RTS,S/AS01(E schedules.Both candidate

  14. Recombinant α-actinin subunit antigens of Trichomonas vaginalis as potential vaccine candidates in protecting against trichomoniasis.

    Science.gov (United States)

    Xie, Yi-Ting; Gao, Jiang-Mei; Wu, Ya-Ping; Tang, Petrus; Hide, Geoff; Lai, De-Hua; Lun, Zhao-Rong

    2017-02-16

    Human trichomoniasis caused by Trichomonas vaginalis is one of the most common sexually transmitted diseases with more than 200 million cases worldwide. It has caused a series of health problems to patients. For prevention and control of infectious diseases, vaccines are usually considered as one of the most cost-efficient tools. However, until now, work on the development of T. vaginalis vaccines is still mainly focused on the screening of potential immunogens. Alpha-actinin characterized by high immunogenicity in T. vaginalis was suggested as a promising candidate. Therefore, the purpose of this study was to evaluate the protective potency of recombinant α-actinin against T. vaginalis infection in a mouse intraperitoneal model. Two selected coding regions of α-actinin (ACT-F, 14-469 aa and ACT-T, 462-844 aa) amplified from cDNA were cloned into pET-32a (+) expression vector and transfected into BL21 cells. After induction with IPTG and purification with electroelution, the two recombinant fusion proteins were emulsified in Freund's adjuvant (FA) and used to immunize BALB/C mice. Following intraperitoneal inoculation with T. vaginalis, the survival rate of mice was monitored for the assessment of protective potency. After immunization, the antibody level in mouse serum was assessed by ELISA, splenocyte proliferation response was detected with CCK8 and cytokines in the supernatant of splenocytes were quantified with a cytometric bead-based assay. We successfully obtained purified ACT-F (70.33 kDa) and ACT-T (61.7kDa). Both recombinant proteins could provide significant protection against T. vaginalis challenge, especially ACT-T (with 100% protection within one month). Meanwhile, high levels of specific total IgG and subtypes (IgG1 > IgG2a) were detected in sera from the immunized mice. Our results also revealed a statistically significant increase in splenocyte proliferation and related cytokine (IFN-γ, IL-6, IL-17A and IL-10) production after repeated

  15. The lead-acid eloflux cell. Research tool and candidate for advanced batteries

    Energy Technology Data Exchange (ETDEWEB)

    Kullmeine, U.; Kappus, W.

    1982-12-01

    The discharge capacity of usual lead-acid cells is limited by several mechanisms among which acid depletion is the most incisive. It is shown that the use of the so-called eloflux principle which is characterized by the flow of electrolyte through the porous electrodes, allows a significant deepe discharge and that by avoiding acid depletion the study of the other limiting processes and their functional dependence on the discharge conditions is possible. From the results it is concluded that an eloflux lead-acid cell is a promising candidate for advanced batteries with high energy density and performance.

  16. Immunogenicity of a virosomally-formulated Plasmodium falciparum GLURP-MSP3 chimeric protein-based malaria vaccine candidate in comparison to adjuvanted formulations

    Directory of Open Access Journals (Sweden)

    Tamborrini Marco

    2011-12-01

    Full Text Available Abstract Background In clinical trials, immunopotentiating reconstituted influenza virosomes (IRIVs have shown great potential as a versatile antigen delivery platform for synthetic peptides derived from Plasmodium falciparum antigens. This study describes the immunogenicity of a virosomally-formulated recombinant fusion protein comprising domains of the two malaria vaccine candidate antigens MSP3 and GLURP. Methods The highly purified recombinant protein GMZ2 was coupled to phosphatidylethanolamine and the conjugates incorporated into the membrane of IRIVs. The immunogenicity of this adjuvant-free virosomal formulation was compared to GMZ2 formulated with the adjuvants Montanide ISA 720 and Alum in three mouse strains with different genetic backgrounds. Results Intramuscular injections of all three candidate vaccine formulations induced GMZ2-specific antibody responses in all mice tested. In general, the humoral immune response in outbred NMRI mice was stronger than that in inbred BALB/c and C57BL/6 mice. ELISA with the recombinant antigens demonstrated immunodominance of the GLURP component over the MSP3 component. However, compared to the Al(OH3-adjuvanted formulation the two other formulations elicited in NMRI mice a larger proportion of anti-MSP3 antibodies. Analyses of the induced GMZ2-specific IgG subclass profiles showed for all three formulations a predominance of the IgG1 isotype. Immune sera against all three formulations exhibited cross-reactivity with in vitro cultivated blood-stage parasites. Immunofluorescence and immunoblot competition experiments showed that both components of the hybrid protein induced IgG cross-reactive with the corresponding native proteins. Conclusion A virosomal formulation of the chimeric protein GMZ2 induced P. falciparum blood stage parasite cross-reactive IgG responses specific for both MSP3 and GLURP. GMZ2 thus represents a candidate component suitable for inclusion into a multi-valent virosomal

  17. WHO informal consultation on scientific basis for regulatory evaluation of candidate human vaccines from plants, Geneva, Switzerland, 24-25 January 2005.

    NARCIS (Netherlands)

    Laan, Jan Willem van der; Minor, Philip; Mahoney, Richard; Arntzen, Charles; Shin, Jinho; Wood, David

    2006-01-01

    In January 2005, WHO convened a meeting of leading experts in plant-derived vaccines and experts from regulatory authorities for an informal discussion on the state-of-the-art and to analyse whether specific guidance might be needed for plant-derived vaccines that is not yet provided by regulatory

  18. Serum-free microcarrier based production of replication deficient Influenza vaccine candidate virus lacking NS1 using Vero cells

    Directory of Open Access Journals (Sweden)

    Yan Mylene L

    2011-08-01

    Full Text Available Abstract Background Influenza virus is a major health concern that has huge impacts on the human society, and vaccination remains as one of the most effective ways to mitigate this disease. Comparing the two types of commercially available Influenza vaccine, the live attenuated virus vaccine is more cross-reactive and easier to administer than the traditional inactivated vaccines. One promising live attenuated Influenza vaccine that has completed Phase I clinical trial is deltaFLU, a deletion mutant lacking the viral Nonstructural Protein 1 (NS1 gene. As a consequence of this gene deletion, this mutant virus can only propagate effectively in cells with a deficient interferon-mediated antiviral response. To demonstrate the manufacturability of this vaccine candidate, a batch bioreactor production process using adherent Vero cells on microcarriers in commercially available animal-component free, serum-free media is described. Results Five commercially available animal-component free, serum-free media (SFM were evaluated for growth of Vero cells in agitated Cytodex 1 spinner flask microcarrier cultures. EX-CELL Vero SFM achieved the highest cell concentration of 2.6 × 10^6 cells/ml, whereas other SFM achieved about 1.2 × 10^6 cells/ml. Time points for infection between the late exponential and stationary phases of cell growth had no significant effect in the final virus titres. A virus yield of 7.6 Log10 TCID50/ml was achieved using trypsin concentration of 10 μg/ml and MOI of 0.001. The Influenza vaccine production process was scaled up to a 3 liter controlled stirred tank bioreactor to achieve a cell density of 2.7 × 10^6 cells/ml and virus titre of 8.3 Log10 TCID50/ml. Finally, the bioreactor system was tested for the production of the corresponding wild type H1N1 Influenza virus, which is conventionally used in the production of inactivated vaccine. High virus titres of up to 10 Log10 TCID50/ml were achieved. Conclusions We describe for the

  19. Hepatitis B vaccination: Efficiency of pretesting by RIA-methods

    Energy Technology Data Exchange (ETDEWEB)

    Hale, T I; Schmid, B

    1984-04-01

    Vaccination of individuals who possess antibodies against HBs virus from a previous infection is not necessary. Health-care personnel represents a large population of potential vaccine recipients. The risk of developing hepatitis B among these workers is proportional to the degree of their exposure to both blood and blood products as well as to patients with hepatitis B. The decision to screen before vaccination depends on the costs of screening, the costs of vaccination, and the likelihood of vaccination candidates having had hepatitis B. We have demonstrated the cost effective use of screening using RIA-methods in a group of health workers for anti-HBs. If care is taken in the organization of the vaccination program, prevaccination screening of vaccine candidates can save considerable amounts of money.

  20. Vaccines for bovine neosporosis: current status and key aspects for development.

    Science.gov (United States)

    Horcajo, P; Regidor-Cerrillo, J; Aguado-Martínez, A; Hemphill, A; Ortega-Mora, L M

    2016-12-01

    Bovine neosporosis is a worldwide concern due to its global distribution and great economic impact. Reproductive failure in cattle due to abortion leads to major economic losses associated with the disease. Currently, there is no treatment or vaccine available against abortion or transmission caused by Neospora caninum infection in cattle. However, vaccination is considered the best measure of control against bovine neosporosis. Several host and parasite factors can influence the dynamics of the infection in bovines. Moreover, the availability of well-defined infection models is a key factor for the evaluation of vaccine candidates. However, working with cattle is not easy due to difficult handling, facilities and costs, and therefore, 'more affordable' models could be used for screening of promising vaccines to establish proof of concept. So far, live-attenuated vaccines have shown good efficacy against exogenous transplacental transmission; however, they have relevant disadvantages and associated risks, which render inactivated or subunit vaccines the best way forward. The identification of novel potential targets and vaccines, and the application of innovative vaccine technologies in harmonized experimental animal models, will accelerate the development of an effective vaccine against bovine neosporosis. © 2016 John Wiley & Sons Ltd.

  1. Safety and immunogenicity of three different formulations of an adjuvanted varicella-zoster virus subunit candidate vaccine in older adults: a phase II, randomized, controlled study

    NARCIS (Netherlands)

    Chlibek, Roman; Smetana, Jan; Pauksens, Karlis; Rombo, Lars; van den Hoek, J. Anneke R.; Richardus, Jan H.; Plassmann, Georg; Schwarz, Tino F.; Ledent, Edouard; Heineman, Thomas C.

    2014-01-01

    This study investigated the safety and immunogenicity of different formulations and schedules of a candidate subunit herpes zoster vaccine containing varicella-zoster virus glycoprotein E (gE) with or without the adjuvant system AS01B. In this phase II, single-blind, randomized, controlled study,

  2. Vaccine-induced toxic epidermal necrolysis: A case and systematic review.

    Science.gov (United States)

    Chahal, Dev; Aleshin, Maria; Turegano, Mamina; Chiu, Melvin; Worswick, Scott

    2018-01-15

    Erythema multiforme (EM), Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are cutaneous hypersensitivityreactions that develop in response to specific triggers such as medications and certain infections. Vaccines, which undergo rigorous safety testing prior to use in humans, are a rare cause of SJS/TEN and little is known about the frequency of such events and corresponding pathogenesis. Herein, we discuss a case of suspected TEN in a 19-year-old woman who received the meningococcal B vaccine (the first report of such an association) and conduct a systematic review of the associated literature. We also discuss management of this patient with a single dose of etanercept. Relevant literature was searched using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method. A total of 29 articles reporting EM, SJS, or TEN following vaccination were included from >5 countries. Of the 29, 22 articles reported EM, 6/29 reported SJS, and 4/29 reported TEN (3 articlesreported cases of both EM and SJS/TEN). We suggest consideration of vaccines as an etiology for cases of SJS or TEN that begin with an EM-like presentation, and provide further evidence for the use of etanercept as a viable treatment for TEN.

  3. Vaccines and Immunization Practice.

    Science.gov (United States)

    Hogue, Michael D; Meador, Anna E

    2016-03-01

    Vaccines are among most cost-effective public health strategies. Despite effective vaccines for many bacterial and viral illnesses, tens of thousands of adults and hundreds of children die each year in the United States from vaccine-preventable diseases. Underutilization of vaccines requires rethinking the approach to incorporating vaccines into practice. Arguably, immunizations could be a part all health care encounters. Shared responsibility is paramount if deaths are to be reduced. This article reviews the available vaccines in the US market, as well as practice recommendations of the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Post-Genomics and Vaccine Improvement for Leishmania

    Science.gov (United States)

    Seyed, Negar; Taheri, Tahereh; Rafati, Sima

    2016-01-01

    Leishmaniasis is a parasitic disease that primarily affects Asia, Africa, South America, and the Mediterranean basin. Despite extensive efforts to develop an effective prophylactic vaccine, no promising vaccine is available yet. However, recent advancements in computational vaccinology on the one hand and genome sequencing approaches on the other have generated new hopes in vaccine development. Computational genome mining for new vaccine candidates is known as reverse vaccinology and is believed to further extend the current list of Leishmania vaccine candidates. Reverse vaccinology can also reduce the intrinsic risks associated with live attenuated vaccines. Individual epitopes arranged in tandem as polytopes are also a possible outcome of reverse genome mining. Here, we will briefly compare reverse vaccinology with conventional vaccinology in respect to Leishmania vaccine, and we will discuss how it influences the aforementioned topics. We will also introduce new in vivo models that will bridge the gap between human and laboratory animal models in future studies. PMID:27092123

  5. A randomized trial assessing the safety and immunogenicity of AS01 and AS02 adjuvanted RTS,S malaria vaccine candidates in children in Gabon.

    Directory of Open Access Journals (Sweden)

    Bertrand Lell

    2009-10-01

    Full Text Available The malaria vaccine candidate antigen RTS,S includes parts of the pre-erythrocytic stage circumsporozoite protein fused to the Hepatitis B surface antigen. Two Adjuvant Systems are in development for this vaccine, an oil-in water emulsion--based formulation (AS02 and a formulation based on liposomes (AS01.In this Phase II, double-blind study (NCT00307021, 180 healthy Gabonese children aged 18 months to 4 years were randomized to receive either RTS,S/AS01(E or RTS,S/AS02(D, on a 0-1-2 month vaccination schedule. The children were followed-up daily for six days after each vaccination and monthly for 14 months. Blood samples were collected at 4 time-points. Both vaccines were well tolerated. Safety parameters were distributed similarly between the two groups. Both vaccines elicited a strong specific immune response after Doses 2 and 3 with a ratio of anti-CS GMT titers (AS02(D/AS01(E of 0.88 (95% CI: 0.68-1.15 post-Dose 3. After Doses 2 and 3 of experimental vaccines, anti-CS and anti-HBs antibody GMTs were higher in children who had been previously vaccinated with at least one dose of hepatitis B vaccine compared to those not previously vaccinated.RTS,S/AS01(E proved similarly as well tolerated and immunogenic as RTS,S/AS02(D, completing an essential step in the age de-escalation process within the RTS,S clinical development plan.ClinicalTrials.gov. NCT00307021.

  6. Análisis de la utilidad de la vacuna Candid 1 en la prevención de la fiebre hemorrágica argentina en niños Analysis of the usefulness of Candid 1 vaccine in preventing Argentine hemorrhagic fever in children

    Directory of Open Access Journals (Sweden)

    María Rosa Feuillade

    2005-08-01

    Full Text Available OBJETIVO: Determinar la estrategia más racional de vacunación con Candid 1 para prevenir la fiebre hemorrágica argentina (FHA en los menores de 15 años que viven en el área endémica. MÉTODOS: Para el análisis de la efectividad estimada se diseñó un modelo de árbol de decisión, con dos posibles opciones: vacunar a todos los menores del área endémica (vacunación ampliada o vacunar solamente a los menores de 15 años con mayor riesgo (vacunación selectiva. Estas opciones se compararon con la alternativa de no vacunar. La evaluación se complementó con un análisis de sensibilidad para identificar los valores umbral de las variables críticas que podrían modificar la decisión tomada. Las probabilidades empleadas se tomaron de estudios clínicos y epidemiológicos previos. RESULTADOS: Según el modelo empleado, la estrategia de vacunación ampliada fue la mejor opción, con una utilidad total esperada de 9,99998 (siendo 10 el valor máximo posible. El análisis de sensibilidad demostró que la vacunación selectiva sería la estrategia de mayor utilidad si la incidencia en la población de bajo riesgo se reduce a menos de 3 por 1 000 000 habitantes o si la tasa de reacciones adversas graves a la vacuna asciende a más de 9 por 100 000 habitantes. Ninguna variación de los parámetros empleados en el modelo respaldó la opción de no vacunar. CONCLUSIONES: Con los parámetros de riesgo y de beneficio empleados, se recomienda vacunar con Candid 1 a todos los menores de 15 años que viven en el área endémica de FHA. El modelo propuesto puede adaptarse a las necesidades futuras y ayudar a tomar decisiones mediante la incorporación de los datos prospectivos de la vigilancia de la enfermedad. Estos resultados pueden usarse como base para estudios de costo y eficacia y para otros análisis cuantitativos.OBJECTIVE: To determine the most rational strategy of vaccination with Candid 1 vaccine in order to prevent Argentine hemorrhagic

  7. Isolation and Characterization of Vaccine Candidate Genes Including CSP and MSP1 in Plasmodium yoelii.

    Science.gov (United States)

    Kim, Seon-Hee; Bae, Young-An; Seoh, Ju-Young; Yang, Hyun-Jong

    2017-06-01

    Malaria is an infectious disease affecting humans, which is transmitted by the bite of Anopheles mosquitoes harboring sporozoites of parasitic protozoans belonging to the genus Plasmodium . Despite past achievements to control the protozoan disease, malaria still remains a significant health threat up to now. In this study, we cloned and characterized the full-unit Plasmodium yoelii genes encoding merozoite surface protein 1 (MSP1), circumsporozoite protein (CSP), and Duffy-binding protein (DBP), each of which can be applied for investigations to obtain potent protective vaccines in the rodent malaria model, due to their specific expression patterns during the parasite life cycle. Recombinant fragments corresponding to the middle and C-terminal regions of PyMSP1 and PyCSP, respectively, displayed strong reactivity against P. yoelii -infected mice sera. Specific native antigens invoking strong humoral immune response during the primary and secondary infections of P. yoelii were also abundantly detected in experimental ICR mice. The low or negligible parasitemia observed in the secondary infected mice was likely to result from the neutralizing action of the protective antibodies. Identification of these antigenic proteins might provide the necessary information and means to characterize additional vaccine candidate antigens, selected solely on their ability to produce the protective antibodies.

  8. Recent advances in the development of vaccines for Ebola virus disease.

    Science.gov (United States)

    Ohimain, Elijah Ige

    2016-01-04

    Ebola virus is one of the most dangerous microorganisms in the world causing hemorrhagic fevers in humans and non-human primates. Ebola virus (EBOV) is a zoonotic infection, which emerges and re-emerges in human populations. The 2014 outbreak was caused by the Zaire strain, which has a kill rate of up to 90%, though 40% was recorded in the current outbreak. The 2014 outbreak is larger than all 20 outbreaks that have occurred since 1976, when the virus was first discovered. It is the first time that the virus was sustained in urban centers and spread beyond Africa into Europe and USA. Thus far, over 22,000 cases have been reported with about 50% mortality in one year. There are currently no approved therapeutics and preventive vaccines against Ebola virus disease (EVD). Responding to the devastating effe1cts of the 2014 outbreak and the potential risk of global spread, has spurred research for the development of therapeutics and vaccines. This review is therefore aimed at presenting the progress of vaccine development. Results showed that conventional inactivated vaccines produced from EBOV by heat, formalin or gamma irradiation appear to be ineffective. However, novel vaccines production techniques have emerged leading to the production of candidate vaccines that have been demonstrated to be effective in preclinical trials using small animal and non-human primates (NHP) models. Some of the promising vaccines have undergone phase 1 clinical trials, which demonstrated their safety and immunogenicity. Many of the candidate vaccines are vector based such as Vesicular Stomatitis Virus (VSV), Rabies Virus (RABV), Adenovirus (Ad), Modified Vaccinia Ankara (MVA), Cytomegalovirus (CMV), human parainfluenza virus type 3 (HPIV3) and Venezuelan Equine Encephalitis Virus (VEEV). Other platforms include virus like particle (VLP), DNA and subunit vaccines. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Vaccination against group B streptococcus.

    Science.gov (United States)

    Heath, Paul T; Feldman, Robert G

    2005-04-01

    Streptococcus agalactiae (Group B streptococcus) is an important cause of disease in infants, pregnant women, the elderly and in immunosuppressed adults. An effective vaccine is likely to prevent the majority of infant disease (both early and late onset), as well as Group B streptococcus-related stillbirths and prematurity, to avoid the current real and theoretical limitations of intrapartum antibiotic prophylaxis, and to be cost effective. The optimal time to administer such a vaccine would be in the third trimester of pregnancy. The main limitations on the production of a Group B streptococcus vaccine are not technical or scientific, but regulatory and legal. A number of candidates including capsular conjugate vaccines using traditional carrier proteins such as tetanus toxoid and mutant diphtheria toxin CRM197, as well as Group B streptococcus-specific proteins such as C5a peptidase, protein vaccines using one or more Group B streptococcus surface proteins and mucosal vaccines, have the potential to be successful vaccines. The capsular conjugate vaccines using tetanus and CRM197 carrier proteins are the most advanced candidates, having already completed Phase II human studies including use in the target population of pregnant women (tetanus toxoid conjugate), however, no definitive protein conjugates have yet been trialed. However, unless the regulatory environment is changed specifically to allow the development of a Group B streptococcus vaccine, it is unlikely that one will ever reach the market.

  10. A live attenuated H7N7 candidate vaccine virus induces neutralizing antibody that confers protection from challenge in mice, ferrets and monkeys

    Science.gov (United States)

    A live attenuated H7N7 candidate vaccine virus was generated by reverse genetics using the modified hemagglutinin (HA) and neuraminidase (NA) genes of HP A/Netherlands/219/03 (NL/03) (H7N7) wild-type (wt) virus and the six internal protein genes of the cold-adapted (ca) A/Ann Arbor/6/60 ca (AA ca) (...

  11. In silico prediction of monovalent and chimeric tetravalent vaccines for prevention and treatment of dengue fever.

    Science.gov (United States)

    Vijayakumar, Subramaniyan; Ramesh, Venkatachalam; Prabhu, Srinivasan; Manogar, Palani

    2017-11-01

    Reverse vaccinology method was used to predict the monovalent peptide vaccine candidate to produce antibodies for therapeutic purpose and to predict tetravalent vaccine candidate to act as a common vaccine to cover all the fever dengue virus serotypes. Envelope (E)-proteins of DENV-1-4 serotypes were used for vaccine prediction using NCBI, Uniprot/Swissprot, Swiss-prot viewer, VaxiJen V2.0, TMHMM, BCPREDS, Propred-1, Propred and MHC Pred,. E-proteins of DENV-1-4 serotypes were identified as antigen from which T cell epitopes, through B cell epitopes, were predicted to act as peptide vaccine candidates. Each selected T cell epitope of E-protein was confirmed to act as vaccine and to induce complementary antibody against particular serotype of dengue virus. Chimeric tetravalent vaccine was formed by the conjugation of four vaccines, each from four dengue serotypes to act as a common vaccine candidate for all the four dengue serotypes. It can be justifiably concluded that the monovalent 9-mer T cell epitope for each DENV serotypes can be used to produce specific antibody agaomst dengue virus and a chimeric common tetravalent vaccine candidate to yield a comparative vaccine to cover any of the four dengue virus serotype. This vaccine is expected to act as highly immunogenic against preventing dengue fever.

  12. Dengue Fever: Causes, Complications, and Vaccine Strategies

    Directory of Open Access Journals (Sweden)

    Niyati Khetarpal

    2016-01-01

    Full Text Available Dengue is a highly endemic infectious disease of the tropical countries and is rapidly becoming a global burden. It is caused by any of the 4 serotypes of dengue virus and is transmitted within humans through female Aedes mosquitoes. Dengue disease varies from mild fever to severe conditions of dengue hemorrhagic fever and shock syndrome. Globalization, increased air travel, and unplanned urbanization have led to increase in the rate of infection and helped dengue to expand its geographic and demographic distribution. Dengue vaccine development has been a challenging task due to the existence of four antigenically distinct dengue virus serotypes, each capable of eliciting cross-reactive and disease-enhancing antibody response against the remaining three serotypes. Recently, Sanofi Pasteur’s chimeric live-attenuated dengue vaccine candidate has been approved in Mexico, Brazil, and Philippines for usage in adults between 9 and 45 years of age. The impact of its limited application to the public health system needs to be evaluated. Simultaneously, the restricted application of this vaccine candidate warrants continued efforts in developing a dengue vaccine candidate which is additionally efficacious for infants and naïve individuals. In this context, alternative strategies of developing a designed vaccine candidate which does not allow production of enhancing antibodies should be explored, as it may expand the umbrella of efficacy to include infants and naïve individuals.

  13. Novel GMO-Based Vaccines against Tuberculosis: State of the Art and Biosafety Considerations.

    Science.gov (United States)

    Leunda, Amaya; Baldo, Aline; Goossens, Martine; Huygen, Kris; Herman, Philippe; Romano, Marta

    2014-06-16

    Novel efficient vaccines are needed to control tuberculosis (TB), a major cause of morbidity and mortality worldwide. Several TB vaccine candidates are currently in clinical and preclinical development. They fall into two categories, the one of candidates designed as a replacement of the Bacille Calmette Guérin (BCG) to be administered to infants and the one of sub-unit vaccines designed as booster vaccines. The latter are designed as vaccines that will be administered to individuals already vaccinated with BCG (or in the future with a BCG replacement vaccine). In this review we provide up to date information on novel tuberculosis (TB) vaccines in development focusing on the risk assessment of candidates composed of genetically modified organisms (GMO) which are currently evaluated in clinical trials. Indeed, these vaccines administered to volunteers raise biosafety concerns with respect to human health and the environment that need to be assessed and managed.

  14. Chikungunya Virus Vaccines: Viral Vector-Based Approaches.

    Science.gov (United States)

    Ramsauer, Katrin; Tangy, Frédéric

    2016-12-15

    In 2013, a major chikungunya virus (CHIKV) epidemic reached the Americas. In the past 2 years, >1.7 million people have been infected. In light of the current epidemic, with millions of people in North and South America at risk, efforts to rapidly develop effective vaccines have increased. Here, we focus on CHIKV vaccines that use viral-vector technologies. This group of vaccine candidates shares an ability to potently induce humoral and cellular immune responses by use of highly attenuated and safe vaccine backbones. So far, well-described vectors such as modified vaccinia virus Ankara, complex adenovirus, vesicular stomatitis virus, alphavirus-based chimeras, and measles vaccine Schwarz strain (MV/Schw) have been described as potential vaccines. We summarize here the recent data on these experimental vaccines, with a focus on the preclinical and clinical activities on the MV/Schw-based candidate, which is the first CHIKV-vectored vaccine that has completed a clinical trial. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

  15. Hepatitis B vaccination: Efficiency of pretesting by RIA-methods

    International Nuclear Information System (INIS)

    Hale, T.I.; Schmid, B.

    1984-01-01

    Vaccination of individuals who possess antibodies against HBs virus from a previous infection is not necessary. Health-care personnel represents a large population of potential vaccine recipients. The risk of developing hepatitis B among these workers is proportional to the degree of their exposure to both blood and blood products as well as to patients with hepatitis B. The decision to screen before vaccination depends on the costs of screening, the costs of vaccination, and the likelihood of vaccination candidates having had hepatitis B. We have demonstrated the cost effective use of screening using RIA-methods in a group of health workers for anti-HBs. If care is taken in the organization of the vaccination program, prevaccination screening of vaccine candidates can save considerable amounts of money. (orig.) [de

  16. Efficacy of RTS,S/AS01E malaria vaccine and exploratory analysis on anti-circumsporozoite antibody titres and protection in children aged 5-17 months in Kenya and Tanzania: a randomised controlled trial

    DEFF Research Database (Denmark)

    Olotu, Ally; Lusingu, John; Leach, Amanda

    2011-01-01

    RTS,S/AS01E is the lead candidate malaria vaccine. We recently showed efficacy against clinical falciparum malaria in 5-17 month old children, during an average of 8 months follow-up. We aimed to assess the efficacy of RTS,S/AS01E during 15 months of follow-up.......RTS,S/AS01E is the lead candidate malaria vaccine. We recently showed efficacy against clinical falciparum malaria in 5-17 month old children, during an average of 8 months follow-up. We aimed to assess the efficacy of RTS,S/AS01E during 15 months of follow-up....

  17. Characterization of Inherent Particles and Mechanism of Thermal Stress Induced Particle Formation in HSV-2 Viral Vaccine Candidate.

    Science.gov (United States)

    Li, Lillian; Kirkitadze, Marina; Bhandal, Kamaljit; Roque, Cristopher; Yang, Eric; Carpick, Bruce; Rahman, Nausheen

    2017-11-10

    Vaccine formulations may contain visible and/or subvisible particles, which can vary in both size and morphology. Extrinsic particles, which are particles not part of the product such as foreign contaminants, are generally considered undesirable and should be eliminated or controlled in injectable products. However, biological products, in particular vaccines, may also contain particles that are inherent to the product. Here we focus on the characterization of visible and subvisible particles in a live, replication-deficient viral vaccine candidate against HSV genital herpes in an early developmental stage. HSV-2 viral vaccine was characterized using a panel of analytical methods, including Fourier transform infrared spectroscopy (FTIR), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Western blot, liquid chromatography-mass spectrometry (LC-MS), light microscopy, transmission electron microscopy (TEM), micro-flow imaging (MFI), dynamic light scattering (DLS), right angle light scattering (RALS), and intrinsic fluorescence. Particles in HSV-2 vaccine typically ranged from hundreds of nanometers to hundreds of micrometers in size and were determined to be inherent to the product. The infectious titer did not correlate with any trend in subvisible particle concentration and size distribution as shown by DLS, MFI, and TEM under stressed conditions. This suggested that particle changes in the submicron range were related to HSV-2 virion structure and had direct impact on biological activity. It was also observed that subvisible and visible particles could induce aggregation in the viral product. The temperature induced aggregation was observed by RALS, intrinsic fluorescence, and DLS. The increase of subvisible particle size with temperature could be fitted to a two-step thermokinetic model. Visible and subvisible particles were found to be inherent to the HSV-2 viral vaccine product. The mechanism of protein aggregation was discussed and a two

  18. Safety and immunogenicity of a candidate parvovirus B19 vaccine.

    Science.gov (United States)

    Bernstein, David I; El Sahly, Hana M; Keitel, Wendy A; Wolff, Mark; Simone, Gina; Segawa, Claire; Wong, Susan; Shelly, Daniel; Young, Neal S; Dempsey, Walla

    2011-10-06

    Parvovirus B19 is an important human pathogen causing erythema infectiosum, transient aplastic crisis in individuals with underlying hemolytic disorders and hydropsfetalis. We therefore evaluated a parvovirus B19 virus like particle (VLP) vaccine. The safety and immunogenicity of a 25 μg dose of parvovirus B19 recombinant capsid; 2.5 and 25 μg doses of the recombinant capsid given with MF59; and saline placebo were assessed in healthy adults. Because of 3 unexplained cutaneous events the study was halted after enrollment of 43 subjects and before any subject received their third scheduled dose. The rashes developed 5-9 days after the first or second injection and were seen in one placebo recipient (without an injection site lesion) and two vaccine recipients (with injection site reactions). No clear cause was established. Other safety evaluations revealed mostly injection site reactions that were mild to moderate with an increase in pain in subjects receiving vaccine and MF59. After dose 2 the majority of vaccine recipients developed ELISA and neutralizing antibody to parvovirus B19. Given the possible severe consequences of parvovirus B19 infection, further development of a safe and effective vaccine continues to be important. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Gene-based vaccine development for improving animal production in developing countries. Possibilities and constraints

    International Nuclear Information System (INIS)

    Egerton, J.R.

    2005-01-01

    For vaccine production, recombinant antigens must be protective. Identifying protective antigens or candidate antigens is an essential precursor to vaccine development. Even when a protective antigen has been identified, cloning of its gene does not lead directly to vaccine development. The fimbrial protein of Dichelobacter nodosus, the agent of foot-rot in ruminants, was known to be protective. Recombinant vaccines against this infection are ineffective if expressed protein subunits are not assembled as mature fimbriae. Antigenic competition between different, but closely related, recombinant antigens limited the use of multivalent vaccines based on this technology. Recombinant antigens may need adjuvants to enhance response. DNA vaccines, potentiated with genes for different cytokines, may replace the need for aggressive adjuvants, and especially where cellular immunity is essential for protection. The expression of antigens from animal pathogens in plants and the demonstration of some immunity to a disease like rinderpest after ingestion of these, suggests an alternative approach to vaccination by injection. Research on disease pathogenesis and the identification of candidate antigens is specific to the disease agent. The definition of expression systems and the formulation of a vaccine for each disease must be followed by research to establish safety and efficacy. Where vaccines are based on unique gene sequences, the intellectual property is likely to be protected by patent. Organizations, licensed to produce recombinant vaccines, expect to recover their costs and to make a profit. The consequence is that genetically-derived vaccines are expensive. The capacity of vaccines to help animal owners of poorer countries depends not only on quality and cost but also on the veterinary infrastructure where they are used. Ensuring the existence of an effective animal health infrastructure in developing countries is as great a challenge for the developed world as

  20. A safe vaccine (DV-STM-07 against Salmonella infection prevents abortion and confers protective immunity to the pregnant and new born mice.

    Directory of Open Access Journals (Sweden)

    Vidya Devi Negi

    Full Text Available Pregnancy is a transient immuno-compromised condition which has evolved to avoid the immune rejection of the fetus by the maternal immune system. The altered immune response of the pregnant female leads to increased susceptibility to invading pathogens, resulting in abortion and congenital defects of the fetus and a subnormal response to vaccination. Active vaccination during pregnancy may lead to abortion induced by heightened cell mediated immune response. In this study, we have administered the highly attenuated vaccine strain DeltapmrG-HM-D (DV-STM-07 in female mice before the onset of pregnancy and followed the immune reaction against challenge with virulent S. Typhimurium in pregnant mice. Here we demonstrate that DV-STM-07 vaccine gives protection against Salmonella in pregnant mice and also prevents Salmonella induced abortion. This protection is conferred by directing the immune response towards Th2 activation and Th1 suppression. The low Th1 response prevents abortion. The use of live attenuated vaccine just before pregnancy carries the risk of transmission to the fetus. We have shown that this vaccine is safe as the vaccine strain is quickly eliminated from the mother and is not transmitted to the fetus. This vaccine also confers immunity to the new born mice of vaccinated mothers. Since there is no evidence of the vaccine candidate reaching the new born mice, we hypothesize that it may be due to trans-colostral transfer of protective anti-Salmonella antibodies. These results suggest that our vaccine DV-STM-07 can be very useful in preventing abortion in the pregnant individuals and confer immunity to the new born. Since there are no such vaccine candidates which can be given to the new born and to the pregnant women, this vaccine holds a very bright future to combat Salmonella induced pregnancy loss.

  1. Adjuvant-Associated Peripheral Blood mRNA Profiles and Kinetics Induced by the Adjuvanted Recombinant Protein Candidate Tuberculosis Vaccine M72/AS01 in Bacillus Calmette–Guérin-Vaccinated Adults

    Directory of Open Access Journals (Sweden)

    Robert A. van den Berg

    2018-03-01

    Full Text Available Systems biology has the potential to identify gene signatures associated with vaccine immunogenicity and protective efficacy. The main objective of this study was to identify optimal postvaccination time points for evaluating peripheral blood RNA expression profiles in relation to vaccine immunogenicity and potential efficacy in recipients of the candidate tuberculosis vaccine M72/AS01. In this phase II open-label study (NCT01669096; https://clinicaltrials.gov/, healthy Bacillus Calmette–Guérin-primed, HIV-negative adults were administered two doses (30 days apart of M72/AS01. Twenty subjects completed the study and 18 subjects received two doses. Blood samples were collected pre-dose 1, pre-dose 2, and 1, 7, 10, 14, 17, and 30 days post-dose 2. RNA expression in whole blood (WB and peripheral blood mononuclear cells (PBMCs was quantified using microarray technology. Serum interferon-gamma responses and M72-specific CD4+ T cell responses to vaccination, and the observed safety profile were similar to previous trials. Two different approaches were utilized to analyze the RNA expression data. First, a kinetic analysis of RNA expression changes using blood transcription modules revealed early (1 day post-dose 2 activation of several pathways related to innate immune activation, both in WB and PBMC. Second, using a previously identified gene signature as a classifier, optimal postvaccination time points were identified. Since M72/AS01 efficacy remains to be established, a PBMC-derived gene signature associated with the protective efficacy of a similarly adjuvanted candidate malaria vaccine was used as a proxy for this purpose. This approach was based on the assumption that the AS01 adjuvant used in both studies could induce shared innate immune pathways. Subjects were classified as gene signature positive (GS+ or gene signature negative (GS−. Assignments of subjects to GS+ or GS− groups were confirmed by significant differences in RNA

  2. Novel GMO-Based Vaccines against Tuberculosis: State of the Art and Biosafety Considerations

    Science.gov (United States)

    Leunda, Amaya; Baldo, Aline; Goossens, Martine; Huygen, Kris; Herman, Philippe; Romano, Marta

    2014-01-01

    Novel efficient vaccines are needed to control tuberculosis (TB), a major cause of morbidity and mortality worldwide. Several TB vaccine candidates are currently in clinical and preclinical development. They fall into two categories, the one of candidates designed as a replacement of the Bacille Calmette Guérin (BCG) to be administered to infants and the one of sub-unit vaccines designed as booster vaccines. The latter are designed as vaccines that will be administered to individuals already vaccinated with BCG (or in the future with a BCG replacement vaccine). In this review we provide up to date information on novel tuberculosis (TB) vaccines in development focusing on the risk assessment of candidates composed of genetically modified organisms (GMO) which are currently evaluated in clinical trials. Indeed, these vaccines administered to volunteers raise biosafety concerns with respect to human health and the environment that need to be assessed and managed. PMID:26344627

  3. Novel GMO-Based Vaccines against Tuberculosis: State of the Art and Biosafety Considerations

    Directory of Open Access Journals (Sweden)

    Amaya Leunda

    2014-06-01

    Full Text Available Novel efficient vaccines are needed to control tuberculosis (TB, a major cause of morbidity and mortality worldwide. Several TB vaccine candidates are currently in clinical and preclinical development. They fall into two categories, the one of candidates designed as a replacement of the Bacille Calmette Guérin (BCG to be administered to infants and the one of sub-unit vaccines designed as booster vaccines. The latter are designed as vaccines that will be administered to individuals already vaccinated with BCG (or in the future with a BCG replacement vaccine. In this review we provide up to date information on novel tuberculosis (TB vaccines in development focusing on the risk assessment of candidates composed of genetically modified organisms (GMO which are currently evaluated in clinical trials. Indeed, these vaccines administered to volunteers raise biosafety concerns with respect to human health and the environment that need to be assessed and managed.

  4. Identification of synthetic vaccine candidates against SARS CoV infection

    International Nuclear Information System (INIS)

    Lien, Shu-Pei; Shih, Yi-Ping; Chen, Hsin-Wei; Tsai, Jy-Ping; Leng, Chih-Hsiang; Lin, Min-Han; Lin, Li-Hsiu; Liu, Hsin-Yu; Chou, Ai-Hsiang; Chang, Yu-Wen; Chen, Yi-Ming A.; Chong, Pele; Liu, Shih-Jen

    2007-01-01

    Three peptides, D1 (amino acid residues 175-201), D2 (a.a. 434-467), and TM (a.a. 1128-1159), corresponding to the spike protein (S) of severe acute respiratory syndrome corona virus (SARS CoV) were synthesized and their immunological functions were investigated in three different animals models (mice, guinea pigs, and rabbits). The peptides mixture formulated either with Freund's adjuvant or synthetic adjuvant Montanide ISA-51/oligodeoxy nucleotide CpG (ISA/CpG) could elicit antisera in immunized animals which were capable of inhibiting SARS/HIV pseudovirus entry into HepG2 cells. The neutralizing epitopes were identified using peptides to block the neutralizing effect of guinea pig antisera. The major neutralizing epitope was located on the D2 peptide, and the amino acid residue was fine mapped to 434-453. In BALB/c mice T-cell proliferation assay revealed that only D2 peptide contained T-cell epitope, the sequence of which corresponded to amino acid residue 434-448. The ISA/CpG formulation generated anti-D2 IgG titer comparable to those obtained from Freund's adjuvant formulation, but generated fewer antibodies against D1 or TM peptides. The highly immunogenic D2 peptide contains both neutralizing and Th cell epitopes. These results suggest that synthetic peptide D2 would be useful as a component of SARS vaccine candidates

  5. Impact of a Plasmodium falciparum AMA1 vaccine on antibody responses in adult Malians.

    Directory of Open Access Journals (Sweden)

    Alassane Dicko

    2007-10-01

    Full Text Available Apical Membrane Antigen 1 (AMA1 of Plasmodium falciparum merozoites is a leading blood-stage malaria vaccine candidate. Protection of Aotus monkeys after vaccination with AMA1 correlates with antibody responses.A randomized, controlled, double-blind phase 1 clinical trial was conducted in 54 healthy Malian adults living in an area of intense seasonal malaria transmission to assess the safety and immunogenicity of the AMA1-C1 malaria vaccine. AMA1-C1 contains an equal mixture of yeast-expressed recombinant proteins based on sequences from the FVO and 3D7 clones of P. falciparum, adsorbed on Alhydrogel. The control vaccine was the hepatitis B vaccine (Recombivax. Participants were enrolled into 1 of 3 dose cohorts (n = 18 per cohort and randomized 2:1 to receive either AMA1-C1 or Recombivax. Participants in the first, second, and third cohorts randomized to receive AMA1-C1 were vaccinated with 5, 20 and 80 microg of AMA1-C1, respectively. Vaccinations were administered on days 0, 28, and 360, and participants were followed until 6 months after the final vaccination. AMA1-C1 was well tolerated; no vaccine-related severe or serious adverse events were observed. AMA1 antibody responses to the 80 microg dose increased rapidly from baseline levels by days 14 and 28 after the first vaccination and continued to increase after the second vaccination. After a peak 14 days following the second vaccination, antibody levels decreased to baseline levels one year later at the time of the third vaccination that induced little or no increase in antibody levels.Although the AMA1-C1 vaccine candidate was well-tolerated and induced antibody responses to both vaccine and non-vaccine alleles, the antibody response after a third dose given at one year was lower than the response to the initial vaccinations. Additionally, post-vaccination increases in anti-AMA1 antibody levels were not associated with significant changes in in vitro growth inhibition of P. falciparum

  6. Rotavirus vaccines and vaccination in Latin America

    Directory of Open Access Journals (Sweden)

    Linhares Alexandre C.

    2000-01-01

    overcome by giving three doses of the rotavirus vaccine or by using a higher-titer formulation of it. Wild enteroviruses, however, may cause primary rotavirus vaccine failure in developing countries. Studies in Peru with RRV-TV have shown a trend towards higher vaccine efficacy rates against "pure" (rotavirus-only diarrheal episodes. Economic analyses made in the United States indicate that a vaccine that costs less than US$ 9 per dose would lead to a net savings in medical costs. To date, however, cost-benefit studies have not been done in developing countries. In the future, it is possible that some Latin American countries might adapt their polio production facilities to the preparation of rotavirus vaccines for human use. A year after RRV-TV was licensed for vaccination of infants in the United States, the occurrence of intussusception as an adverse event led to the vaccine's withdrawal from the market. The implications of that action, particularly for Latin America, will be addressed in this article, including the need to explore alternative rotavirus candidate vaccines, particularly through the conduct of parallel clinical trials in both developed and developing countries.

  7. Rotavirus vaccines and vaccination in Latin America

    Directory of Open Access Journals (Sweden)

    Alexandre C. Linhares

    2000-11-01

    overcome by giving three doses of the rotavirus vaccine or by using a higher-titer formulation of it. Wild enteroviruses, however, may cause primary rotavirus vaccine failure in developing countries. Studies in Peru with RRV-TV have shown a trend towards higher vaccine efficacy rates against "pure" (rotavirus-only diarrheal episodes. Economic analyses made in the United States indicate that a vaccine that costs less than US$ 9 per dose would lead to a net savings in medical costs. To date, however, cost-benefit studies have not been done in developing countries. In the future, it is possible that some Latin American countries might adapt their polio production facilities to the preparation of rotavirus vaccines for human use. A year after RRV-TV was licensed for vaccination of infants in the United States, the occurrence of intussusception as an adverse event led to the vaccine's withdrawal from the market. The implications of that action, particularly for Latin America, will be addressed in this article, including the need to explore alternative rotavirus candidate vaccines, particularly through the conduct of parallel clinical trials in both developed and developing countries.

  8. Application of “Systems Vaccinology” to Evaluate Inflammation and Reactogenicity of Adjuvanted Preventative Vaccines

    Directory of Open Access Journals (Sweden)

    David J. M. Lewis

    2015-01-01

    Full Text Available Advances in “omics” technology (transcriptomics, proteomics, metabolomics, genomics/epigenomics, etc. allied with statistical and bioinformatics tools are providing insights into basic mechanisms of vaccine and adjuvant efficacy or inflammation/reactogenicity. Predictive biomarkers of relatively frequent inflammatory reactogenicity may be identified in systems vaccinology studies involving tens or hundreds of participants and used to screen new vaccines and adjuvants in in vitro, ex vivo, animal, or human models. The identification of rare events (such as those observed with initial rotavirus vaccine or suspected autoimmune complications will require interrogation of large data sets and population-based research before application of systems vaccinology. The Innovative Medicine Initiative funded public-private project BIOVACSAFE is an initial attempt to systematically identify biomarkers of relatively common inflammatory events after adjuvanted immunization using human, animal, and population-based models. Discriminatory profiles or biomarkers are being identified, which require validation in large trials involving thousands of participants before they can be generalized. Ultimately, it is to be hoped that the knowledge gained from such initiatives will provide tools to the industry, academia, and regulators to select optimal noninflammatory but immunogenic and effective vaccine adjuvant combinations, thereby shortening product development cycles and identifying unsuitable vaccine candidates that would fail in expensive late stage development or postmarketing.

  9. Issues in the economic evaluation of influenza vaccination by injection of healthy working adults in the US: a review and decision analysis of ten published studies.

    Science.gov (United States)

    Hogan, Thomas J

    2012-05-01

    The objective was to review recent economic evaluations of influenza vaccination by injection in the US, assess their evidence, and conclude on their collective findings. The literature was searched for economic evaluations of influenza vaccination injection in healthy working adults in the US published since 1995. Ten evaluations described in nine papers were identified. These were synopsized and their results evaluated, the basic structure of all evaluations was ascertained, and sensitivity of outcomes to changes in parameter values were explored using a decision model. Areas to improve economic evaluations were noted. Eight of nine evaluations with credible economic outcomes were favourable to vaccination, representing a statistically significant result compared with a proportion of 50% that would be expected if vaccination and no vaccination were economically equivalent. Evaluations shared a basic structure, but differed considerably with respect to cost components, assumptions, methods, and parameter estimates. Sensitivity analysis indicated that changes in parameter values within the feasible range, individually or simultaneously, could reverse economic outcomes. Given stated misgivings, the methods of estimating influenza reduction ascribed to vaccination must be researched to confirm that they produce accurate and reliable estimates. Research is also needed to improve estimates of the costs per case of influenza illness and the costs of vaccination. Based on their assumptions, the reviewed papers collectively appear to support the economic benefits of influenza vaccination of healthy adults. Yet the underlying assumptions, methods and parameter estimates themselves warrant further research to confirm they are accurate, reliable and appropriate to economic evaluation purposes.

  10. Vaccines: an ongoing promise?

    Science.gov (United States)

    Alsahli, M; Farrell, R J; Michetti, P

    2001-01-01

    Over the past decade, intensive research has focused on developing a vaccine therapy for Helicobacter pylori. Substantial unresolved questions cloud the current approach, and the development of a vaccine against this unique organism has proved very challenging. Many candidate vaccines have been tested in animal models. The immunogenicity and the safety of some vaccine formulations have been recently evaluated through clinical trials, and the efficacy of these vaccine therapies in humans will be determined in the near future. This article will provide an overview of the current knowledge of natural and vaccine-induced immune responses to H. pylori infection. It will also review past vaccine successes and failures in animal models and the limited experience to date in using vaccine therapy in humans. Several obstacles to H. pylori vaccine development efforts along with the future direction of these efforts will be discussed. Copyright 2001 S. Karger AG, Basel

  11. Modeling The Economic Burden Of Adult Vaccine-Preventable Diseases In The United States.

    Science.gov (United States)

    Ozawa, Sachiko; Portnoy, Allison; Getaneh, Hiwote; Clark, Samantha; Knoll, Maria; Bishai, David; Yang, H Keri; Patwardhan, Pallavi D

    2016-11-01

    Vaccines save thousands of lives in the United States every year, but many adults remain unvaccinated. Low rates of vaccine uptake lead to costs to individuals and society in terms of deaths and disabilities, which are avoidable, and they create economic losses from doctor visits, hospitalizations, and lost income. To identify the magnitude of this problem, we calculated the current economic burden that is attributable to vaccine-preventable diseases among US adults. We estimated the total remaining economic burden at approximately $9 billion (plausibility range: $4.7-$15.2 billion) in a single year, 2015, from vaccine-preventable diseases related to ten vaccines recommended for adults ages nineteen and older. Unvaccinated individuals are responsible for almost 80 percent, or $7.1 billion, of the financial burden. These results not only indicate the potential economic benefit of increasing adult immunization uptake but also highlight the value of vaccines. Policies should focus on minimizing the negative externalities or spillover effects from the choice not to be vaccinated, while preserving patient autonomy. Project HOPE—The People-to-People Health Foundation, Inc.

  12. Immunogenicity and Safety of Yellow Fever Vaccine (Stamaril) When Administered Concomitantly With a Tetravalent Dengue Vaccine Candidate in Healthy Toddlers at 12-13 Months of Age in Colombia and Peru: A Randomized Trial.

    Science.gov (United States)

    López, Pio; Lanata, Claudio F; Zambrano, Betzana; Cortés, Margarita; Andrade, Teresa; Amemiya, Isabel; Terrones, Cynthia; Gil, Ana I; Verastegui, Hector; Marquez, Viviana; Crevat, Denis; Jezorwski, John; Noriega, Fernando

    2016-10-01

    Dengue and yellow fever (YF) viruses are closely related members of the Flaviviridae family. Given the inherent similarities between the YF vaccine and dengue vaccine (CYD-TDV) candidate, it is possible that the latter could interfere with the response to the licensed YF vaccine when coadministered. In this randomized, observer-blind, controlled, phase III trial, conducted in Colombia and Peru, 787 toddlers were administered YF vaccine concomitantly with CYD-TDV (group 1) or placebo (group 2), followed by CYD-TDV after 6 and 12 months. YF and dengue neutralizing antibody titers were determined using a 50% plaque reduction neutralization test. Noninferiority was demonstrated if the lower limit of the 2-sided 95% confidence interval of the difference in seroconversion rates [(YF + CYD-TDV) - YF alone] was greater than -10%. The safety of both vaccines was also assessed. Concomitant administration of YF with either CYD-TDV or placebo yielded YF seroconversion rates of 100.0% and 99.7%, respectively. The difference in YF seroconversion rates between the 2 groups was 0.33% (95% confidence interval:0.98; 1.87), demonstrating that the immune response against YF administered concomitantly with CYD-TDV was noninferior to YF administered with placebo. After 2 injections of CYD-TDV, the percentage of participants with dengue titres ≥10 (1/dil) for the 4 dengue serotypes were 91.2%-100% for group 1 and 97.2%-100% in group 2. There were no safety concerns during the study period. Concomitant administration of YF vaccine with CYD-TDV has no relevant impact on the immunogenicity or safety profile of the YF vaccine.

  13. Immunogenicity and Efficacy of Live L. tarentolae Expressing KMP11-NTGP96-GFP Fusion as a Vaccine Candidate against Experimental Visceral Leishmaniasis Caused by L. infantum

    Directory of Open Access Journals (Sweden)

    Vahid NASIRI

    2016-10-01

    Full Text Available Background: The aim of present study was to evaluate the protective efficacy of live recombinant L. tarentolae expressing KMP11-NTGP96-GFP fusion as candidates for live engineered recombinant vaccine against visceral leishmaniasis in BALB/c mice.Methods: KMP-11 and NT-GP96 genes cloned into the pJET1.2/blunt cloning vector and then into pEGFP-N1 expression vector. The KMP-11, NT-GP96 and GFP fused in pEGFP-N1 and subcloned into Leishmanian pLEXSY-neo vector. Finally this construct was transferred to L. tarentolae by electroporation. Tranfection was confirmed by SDS-PAGE, WESTERN blot, flowcytometry and RT-PCR. Protective efficacy of this construct was evaluated as a vaccine candidate against visceral leishmaniasis. Parasite burden, humoral and cellular immune responses were assessed before and at 4 weeks after challenge.Results: KMP- NT-Gp96-GFP Fusion was cloned successfully into pLEXSY -neo vector and this construct successfully transferred to L. tarentolae. Finding indicated that immunization with L. tarentolae tarentolae-KMP11-NTGP96-GFP provides significant protection against visceral leishmaniasis and was able to induce an increased expression of IFN-γ and IgG2a. Following challenge, a reduced parasite load in the spleen of the KMP11-NTGP96-GFP immunized group was detected.Conclusion: The present study is the first to use a combination of a Leishmania antigen with an immunologic antigen in live recombinant L. tarentolae and results suggest that L. tarentolae-KMP11-NTGP96-GFP could be considered as a potential tool in vaccination against visceral leishmaniasis and this vaccination strategy could provide a potent rout for future vaccine development. 

  14. Effect of vaccination with an inactivated vaccine on transplacental transmission of BTV-8 in mid term pregnant ewes and heifers

    NARCIS (Netherlands)

    Sluijs, van der M.T.W.; Schroer-Joosten, D.P.H.; Fid-Fourkour, A.; Vrijenhoek, M.; Debyser, I.; Gregg, D.A.; Dufe, D.M.; Moulin, V.; Moormann, R.J.M.; Smit, de A.J.

    2012-01-01

    The effect of vaccination with a commercial inactivated Bluetongue virus serotype 8 (BTV-8) vaccine on the ability of BTV-8 to cross the ruminant placenta was investigated in two experiments. Ten pregnant ewes (Experiment 1) or heifers (Experiment 2) were vaccinated according to the manufacturer's

  15. Idala: An unnamed Function Peptide Vaccine for Tuberculosis

    African Journals Online (AJOL)

    Color development in a microplate reader was ... peptide vaccine for tuberculosis tested by mice immunogenicity experiment. Keywords: ... potential new tuberculosis vaccine candidate. [3]. ..... New York and London: Garland Science,.

  16. Bronchus-associated lymphoid tissue (BALT and survival in a vaccine mouse model of tularemia.

    Directory of Open Access Journals (Sweden)

    Damiana Chiavolini

    2010-06-01

    Full Text Available Francisella tularensis causes severe pulmonary disease, and nasal vaccination could be the ideal measure to effectively prevent it. Nevertheless, the efficacy of this type of vaccine is influenced by the lack of an effective mucosal adjuvant.Mice were immunized via the nasal route with lipopolysaccharide isolated from F. tularensis and neisserial recombinant PorB as an adjuvant candidate. Then, mice were challenged via the same route with the F. tularensis attenuated live vaccine strain (LVS. Mouse survival and analysis of a number of immune parameters were conducted following intranasal challenge. Vaccination induced a systemic antibody response and 70% of mice were protected from challenge as showed by their improved survival and weight regain. Lungs from mice recovering from infection presented prominent lymphoid aggregates in peribronchial and perivascular areas, consistent with the location of bronchus-associated lymphoid tissue (BALT. BALT areas contained proliferating B and T cells, germinal centers, T cell infiltrates, dendritic cells (DCs. We also observed local production of antibody generating cells and homeostatic chemokines in BALT areas.These data indicate that PorB might be an optimal adjuvant candidate for improving the protective effect of F. tularensis antigens. The presence of BALT induced after intranasal challenge in vaccinated mice might play a role in regulation of local immunity and long-term protection, but more work is needed to elucidate mechanisms that lead to its formation.

  17. Approaches and Perspectives for Development of African Swine Fever Virus Vaccines

    Directory of Open Access Journals (Sweden)

    Marisa Arias

    2017-10-01

    Full Text Available African swine fever (ASF is a complex disease of swine, caused by a large DNA virus belonging to the family Asfarviridae. The disease shows variable clinical signs, with high case fatality rates, up to 100%, in the acute forms. ASF is currently present in Africa and Europe where it circulates in different scenarios causing a high socio-economic impact. In most affected regions, control has not been effective in part due to lack of a vaccine. The availability of an effective and safe ASFV vaccines would support and enforce control–eradication strategies. Therefore, work leading to the rational development of protective ASF vaccines is a high priority. Several factors have hindered vaccine development, including the complexity of the ASF virus particle and the large number of proteins encoded by its genome. Many of these virus proteins inhibit the host’s immune system thus facilitating virus replication and persistence. We review previous work aimed at understanding ASFV–host interactions, including mechanisms of protective immunity, and approaches for vaccine development. These include live attenuated vaccines, and “subunit” vaccines, based on DNA, proteins, or virus vectors. In the shorter to medium term, live attenuated vaccines are the most promising and best positioned candidates. Gaps and future research directions are evaluated.

  18. Maximizing protection from use of oral cholera vaccines in developing country settings

    Science.gov (United States)

    Desai, Sachin N; Cravioto, Alejandro; Sur, Dipika; Kanungo, Suman

    2014-01-01

    When oral vaccines are administered to children in lower- and middle-income countries, they do not induce the same immune responses as they do in developed countries. Although not completely understood, reasons for this finding include maternal antibody interference, mucosal pathology secondary to infection, malnutrition, enteropathy, and previous exposure to the organism (or related organisms). Young children experience a high burden of cholera infection, which can lead to severe acute dehydrating diarrhea and substantial mortality and morbidity. Oral cholera vaccines show variations in their duration of protection and efficacy between children and adults. Evaluating innate and memory immune response is necessary to understand V. cholerae immunity and to improve current cholera vaccine candidates, especially in young children. Further research on the benefits of supplementary interventions and delivery schedules may also improve immunization strategies. PMID:24861554

  19. AIDS vaccine: Present status and future challenges

    Directory of Open Access Journals (Sweden)

    Nigam P

    2006-01-01

    Full Text Available Development of a preventive vaccine for HIV is the best hope of controlling the AIDS pandemic. HIV has, however, proved a difficult pathogen to vaccinate against because of its very high mutation rate and capability to escape immune responses. Neutralizing antibodies that can neutralize diverse field strains have so far proved difficult to induce. Adjuvanting these vaccines with cytokine plasmids and a "prime-boost," approach is being evaluated in an effort to induce both CTL and antibody responses and thereby have immune responses active against both infected cells and free viral particles, thereby necessitating fewer doses of recombinant protein to reach maximum antibodies titers. Although obstacles exist in evaluation of candidate HIV vaccines, evidence from natural history studies, new molecular tools in virology and immunology, new adjuvants, new gene expression systems, new antigen delivery systems, recent discoveries in HIV entry and pathogenesis, and promising studies of candidate vaccines in animal models have provided reasons to hope that developing a safe and effective AIDS vaccine is possible and within reach.

  20. A novel chimeric protein composed of recombinant Mycoplasma hyopneumoniae antigens as a vaccine candidate evaluated in mice.

    Science.gov (United States)

    de Oliveira, Natasha Rodrigues; Jorge, Sérgio; Gomes, Charles Klazer; Rizzi, Caroline; Pacce, Violetta Dias; Collares, Thais Farias; Monte, Leonardo Garcia; Dellagostin, Odir Antônio

    2017-03-01

    Enzootic Pneumonia (EP) is caused by the Mycoplasma hyopneumoniae pathogenic bacteria, and it represents a significant respiratory disease that is responsible for major economic losses within the pig industry throughout the world. The bacterins that are currently commercially available have been proven to offer only partial protection against M. hyopneumoniae, and the development of more efficient vaccines is required. Several recombinant antigens have been evaluated via different immunization strategies and have been found to be highly immunogenic. This work describes the construction and immunological characterization of a multi-antigen chimera composed of four M. hyopneumoniae antigens: P97R1, P46, P95, and P42. Immunogenic regions of each antigen were selected and combined to encode a single polypeptide. The gene was cloned and expressed in Escherichia coli, and the chimeric protein was recognized by specific antibodies against each subunit, as well as by convalescent pig sera. The immunogenic properties of the chimera were then evaluated in a mice model through two recombinant vaccines that were formulated as follows: (1) purified chimeric protein plus adjuvant or (2) recombinant Escherichia coli bacterin. The immune response induced in BALB/c mice immunized with each formulation was characterized in terms of total IgG levels, IgG1, and IgG2a isotypes against each antigen present in the chimera. The results of the study indicated that novel chimeric protein is a potential candidate for the future development of a more effective vaccine against EP. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Development of Au-Ge based candidate alloys as an alternative to high-lead content solders

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hald, John; Hattel, Jesper Henri

    2010-01-01

    Au-Ge based candidate alloys have been proposed as an alternative to high-lead content solders that are currently being used for high-temperature applications. The changes in microstructure and microhardness associated with the addition of low melting point metals namely In, Sb and Sn to the Au......-Ge-In and Au-Ge-Sn combinations was determined to be the classic solid solution strengthening. The Au-Ge-Sb combination was primarily strengthened by the refined (Ge) dispersed phase. The aging temperature had a significant influence on the microhardness in the case of the Au-Ge-Sn candidate alloy...

  2. From genomes to vaccines: Leishmania as a model.

    Science.gov (United States)

    Almeida, Renata; Norrish, Alan; Levick, Mark; Vetrie, David; Freeman, Tom; Vilo, Jaak; Ivens, Alasdair; Lange, Uta; Stober, Carmel; McCann, Sharon; Blackwell, Jenefer M

    2002-01-01

    The 35 Mb genome of Leishmania should be sequenced by late 2002. It contains approximately 8500 genes that will probably translate into more than 10 000 proteins. In the laboratory we have been piloting strategies to try to harness the power of the genome-proteome for rapid screening of new vaccine candidate. To this end, microarray analysis of 1094 unique genes identified using an EST analysis of 2091 cDNA clones from spliced leader libraries prepared from different developmental stages of Leishmania has been employed. The plan was to identify amastigote-expressed genes that could be used in high-throughput DNA-vaccine screens to identify potential new vaccine candidates. Despite the lack of transcriptional regulation that polycistronic transcription in Leishmania dictates, the data provide evidence for a high level of post-transcriptional regulation of RNA abundance during the developmental cycle of promastigotes in culture and in lesion-derived amastigotes of Leishmania major. This has provided 147 candidates from the 1094 unique genes that are specifically upregulated in amastigotes and are being used in vaccine studies. Using DNA vaccination, it was demonstrated that pooling strategies can work to identify protective vaccines, but it was found that some potentially protective antigens are masked by other disease-exacerbatory antigens in the pool. A total of 100 new vaccine candidates are currently being tested separately and in pools to extend this analysis, and to facilitate retrospective bioinformatic analysis to develop predictive algorithms for sequences that constitute potentially protective antigens. We are also working with other members of the Leishmania Genome Network to determine whether RNA expression determined by microarray analyses parallels expression at the protein level. We believe we are making good progress in developing strategies that will allow rapid translation of the sequence of Leishmania into potential interventions for disease

  3. Limited variation in vaccine candidate Plasmodium falciparum Merozoite Surface Protein-6 over multiple transmission seasons

    Directory of Open Access Journals (Sweden)

    Branch OraLee H

    2010-05-01

    same community. By contrast, PfMSP6 was highly stable at the sequence level, with no SNPs detected in the 506 samples analysed. This limited diversity supports further investigation of PfMSP6 as a blood stage vaccine candidate, with the clear caveat that any such vaccine must either contain both alleles or generate cross-protective responses that react against both allele classes. Detailed immunoepidemiology studies are needed to establish the viability of these approaches before PfMSP6 advances further down the vaccine development pipeline.

  4. Dengue human infection models to advance dengue vaccine development.

    Science.gov (United States)

    Larsen, Christian P; Whitehead, Stephen S; Durbin, Anna P

    2015-12-10

    Dengue viruses (DENV) currently infect approximately 400 million people each year causing millions to seek care and overwhelming the health care infrastructure in endemic areas. Vaccines to prevent dengue and therapeutics to treat dengue are not currently available. The efficacy of the most advanced candidate vaccine against symptomatic dengue in general and DENV-2 in particular was much lower than expected, despite the ability of the vaccine to induce neutralizing antibody against all four DENV serotypes. Because seroconversion to the DENV serotypes following vaccination was thought to be indicative of induced protection, these results have made it more difficult to assess which candidate vaccines should or should not be evaluated in large studies in endemic areas. A dengue human infection model (DHIM) could be extremely valuable to down-select candidate vaccines or therapeutics prior to engaging in efficacy trials in endemic areas. Two DHIM have been developed to assess the efficacy of live attenuated tetravalent (LATV) dengue vaccines. The first model, developed by the Laboratory of Infectious Diseases at the U. S. National Institutes of Health, utilizes a modified DENV-2 strain DEN2Δ30. This virus was derived from the DENV-2 Tonga/74 that caused only very mild clinical infection during the outbreak from which it was recovered. DEN2Δ30 induced viremia in 100%, rash in 80%, and neutropenia in 27% of the 30 subjects to whom it was given. The Walter Reed Army Institute of Research (WRAIR) is developing a DHIM the goal of which is to identify DENV that cause symptomatic dengue fever. WRAIR has evaluated seven viruses and has identified two that meet dengue fever criteria. Both of these models may be very useful in the evaluation and down-selection of candidate dengue vaccines and therapeutics. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  5. Development of recombinant vaccine candidate molecule against Shigella infection.

    Science.gov (United States)

    Chitradevi, S T S; Kaur, G; Sivaramakrishna, U; Singh, D; Bansal, A

    2016-10-17

    Shigellosis is an acute bacillary diarrheal disease caused by the gram negative bacillus Shigella. The existence of multiple Shigella serotypes and their growing resistance to antibiotics stress the urgent need for the development of vaccine that is protective across all serotypes. Shigella's IpaB antigen is involved in translocon pore formation, promotes bacterial invasion and induces apoptosis in macrophages. S. Typhi GroEL (Hsp 60) is the immunodominant antigen inducing both arms of immunity and has been explored as adjuvant in this study. The present study evaluates the immunogenicity and protective efficacy of recombinant IpaB domain-GroEL fusion protein in mice against lethal Shigella infection. The IpaB domain and GroEL genes were fused using overlap extension PCR and cloned in pRSETA expression vector. Fused gene was expressed in Escherichia coli BL-21 cells and the resulting 90 KDa fusion protein was purified by affinity chromatography. Intranasal (i.n.) immunization of mice with fusion protein increased the IgG and IgA antibody titers as compared to the group immunized with IpaB and GroEL and control PBS immunized group. Also IgG1 and IgG2a antibodies induced in fusion protein immunized mice were higher than co-immunized group. Significant increase in lymphocyte proliferation and cytokine levels (IFN-γ, IL-4 and IL-10), indicates induction of both Th1 and Th2 immune responses in both immunized groups. Immunization with fusion protein protected 90-95% of mice whereas 80-85% survivability was observed in co-immunized group against lethal challenge with S. flexneri, S. boydii and S. sonnei. Passive immunization conferred 60-70% protection in mice against all these Shigella species. Organ burden and histopathology studies also revealed significant decrease in lung infection as compared to the co-immunized group. Since IpaB is the conserved dominant molecule in all Shigella species, this study will lead to an ideal platform for the development of safe

  6. Prescreening of Nicotine Hapten Linkers in Vitro To Select Hapten-Conjugate Vaccine Candidates for Pharmacokinetic Evaluation in Vivo.

    Science.gov (United States)

    Arutla, Viswanath; Leal, Joseph; Liu, Xiaowei; Sokalingam, Sriram; Raleigh, Michael; Adaralegbe, Adejimi; Liu, Li; Pentel, Paul R; Hecht, Sidney M; Chang, Yung

    2017-05-08

    Since the demonstration of nicotine vaccines as a possible therapeutic intervention for the effects of tobacco smoke, extensive effort has been made to enhance nicotine specific immunity. Linker modifications of nicotine haptens have been a focal point for improving the immunogenicity of nicotine, in which the evaluation of these modifications usually relies on in vivo animal models, such as mice, rats or nonhuman primates. Here, we present two in vitro screening strategies to estimate and predict the immunogenic potential of our newly designed nicotine haptens. One utilizes a competition enzyme-linked immunoabsorbent assay (ELISA) to profile the interactions of nicotine haptens or hapten-protein conjugates with nicotine specific antibodies, both polyclonal and monoclonal. Another relies on computational modeling of the interactions between haptens and amino acid residues near the conjugation site of the carrier protein to infer linker-carrier protein conjugation effect on antinicotine antibody response. Using these two in vitro methods, we ranked the haptens with different linkers for their potential as viable vaccine candidates. The ELISA-based hapten ranking was in an agreement with the results obtained by in vivo nicotine pharmacokinetic analysis. A correlation was found between the average binding affinity (IC 50 ) of the haptens to an anti-Nic monoclonal antibody and the average brain nicotine concentration in the immunized mice. The computational modeling of hapten and carrier protein interactions helps exclude conjugates with strong linker-carrier conjugation effects and low in vivo efficacy. The simplicity of these in vitro screening strategies should facilitate the selection and development of more effective nicotine conjugate vaccines. In addition, these data highlight a previously under-appreciated contribution of linkers and hapten-protein conjugations to conjugate vaccine immunogenicity by virtue of their inclusion in the epitope that binds and

  7. A new strategy based on SmRho protein loaded chitosan nanoparticles as a candidate oral vaccine against schistosomiasis.

    Directory of Open Access Journals (Sweden)

    Carolina R Oliveira

    Full Text Available BACKGROUND: Schistosomiasis is one of the most important neglected tropical diseases and an effective control is unlikely in the absence of improved sanitation and vaccination. A new approach of oral vaccination with alginate coated chitosan nanoparticles appears interesting because their great stability and the ease of target accessibility, besides of chitosan and alginate immunostimulatory properties. Here we propose a candidate vaccine based on the combination of chitosan-based nanoparticles containing the antigen SmRho and coated with sodium alginate. METHODS AND FINDINGS: Our results showed an efficient performance of protein loading of nanoparticles before and after coating with alginate. Characterization of the resulting nanoparticles reported a size around 430 nm and a negative zeta potential. In vitro release studies of protein showed great stability of coated nanoparticles in simulated gastric fluid (SGF and simulated intestinal fluid (SIF. Further in vivo studies was performed with different formulations of chitosan nanoparticles and it showed that oral immunization was not able to induce high levels of antibodies, otherwise intramuscular immunization induced high levels of both subtypes IgG1 and IgG2a SmRho specific antibodies. Mice immunized with nanoparticles associated to CpG showed significant modulation of granuloma reaction. Mice from all groups immunized orally with nanoparticles presented significant levels of protection against infection challenge with S. mansoni worms, suggesting an important role of chitosan in inducing a protective immune response. Finally, mice immunized with nanoparticles associated with the antigen SmRho plus CpG had 38% of the granuloma area reduced and also presented 48% of protection against of S. mansoni infection. CONCLUSIONS: Taken together, this results support this new strategy as an efficient delivery system and a potential vaccine against schistosomiasis.

  8. In a randomized trial, the live attenuated tetravalent dengue vaccine TV003 is well-tolerated and highly immunogenic in subjects with flavivirus exposure prior to vaccination.

    Directory of Open Access Journals (Sweden)

    Stephen S Whitehead

    2017-05-01

    Full Text Available Infection caused by the four serotypes of dengue virus (DENV-1-4 is a leading cause of mosquito-borne disease. Clinically-severe dengue disease is more common when secondary dengue infection occurs following prior infection with a heterologous dengue serotype. Other flaviviruses such as yellow fever virus, Japanese encephalitis virus, and Zika virus, can also elicit antibodies which are cross-reactive to DENV. As candidate dengue vaccines become available in endemic settings and for individuals who have received other flavivirus vaccines, it is important to examine vaccine safety and immunogenicity in these flavivirus-experienced populations. We performed a randomized, controlled trial of the National Institutes of Health live attenuated tetravalent dengue vaccine candidate (TV003 in fifty-eight individuals with prior exposure to flavivirus infection or vaccine. As in prior studies of this vaccine in flavivirus-naive volunteers, flavivirus-experienced subjects received two doses of vaccine six months apart and were followed closely for clinical events, laboratory changes, viremia, and neutralizing antibody titers. TV003 was well tolerated with few adverse events other than rash, which was predominately mild. Following one dose, 87% of vaccinees had an antibody response to all four serotypes (tetravalent response, suggesting a robust immune response. In addition, 76% of vaccinees were viremic; mean peak titers ranged from 0.68–1.1 log10 PFU/mL and did not differ by serotype. The second dose of TV003 was not associated with viremia, rash, or a sustained boost in antibody titers indicating that a single dose of the vaccine is likely sufficient to prevent viral replication and thus protect against disease. In comparison to the viremia and neutralizing antibody response elicited by TV003 in flavivirus-naïve subjects from prior studies, we found that subjects who were flavivirus-exposed prior to vaccination exhibited slightly higher DENV-3 viremia

  9. Vaccines. An Ebola whole-virus vaccine is protective in nonhuman primates.

    Science.gov (United States)

    Marzi, Andrea; Halfmann, Peter; Hill-Batorski, Lindsay; Feldmann, Friederike; Shupert, W Lesley; Neumann, Gabriele; Feldmann, Heinz; Kawaoka, Yoshihiro

    2015-04-24

    Zaire ebolavirus is the causative agent of the current outbreak of hemorrhagic fever disease in West Africa. Previously, we showed that a whole Ebola virus (EBOV) vaccine based on a replication-defective EBOV (EBOVΔVP30) protects immunized mice and guinea pigs against lethal challenge with rodent-adapted EBOV. Here, we demonstrate that EBOVΔVP30 protects nonhuman primates against lethal infection with EBOV. Although EBOVΔVP30 is replication-incompetent, we additionally inactivated the vaccine with hydrogen peroxide; the chemically inactivated vaccine remained antigenic and protective in nonhuman primates. EBOVΔVP30 thus represents a safe, efficacious, whole-EBOV vaccine candidate that differs from other EBOV vaccine platforms in that it presents all viral proteins and the viral RNA to the host immune system, which might contribute to protective immune responses. Copyright © 2015, American Association for the Advancement of Science.

  10. Serotype distribution of Streptococcus pneumoniae isolated from patients with invasive pneumococcal disease in Brazil before and after ten-pneumococcal conjugate vaccine implementation.

    Science.gov (United States)

    dos Santos, Silvia R; Passadore, Lilian F; Takagi, Elizabeth H; Fujii, Cristiane M; Yoshioka, Cristina R M; Gilio, Alfredo E; Martinez, Marina B

    2013-12-09

    The ten-pneumococcal conjugate vaccine (PCV10) was introduced into the national immunization program for childhood vaccination schedules by the Brazilian Health Public Service in March 2010. The aim of this study was to compare Streptococcus pneumoniae serotype distribution, antibiotic resistance patterns, and potential coverage before (January 2006-June 2010) and after (July 2010-September 2012) PCV10 introduction. The incidence of invasive pneumococcal disease (IPD), patient demographics, and disease characteristics were recorded. This study was conducted at the University Hospital of Sao Paulo University in Brazil from January 2006 to September 2012. Serotyping was performed using multiplex PCR typing, and antimicrobial sensitivity by Clinical and Laboratory Standards Institute (CLSI). A total of 259 S. pneumoniae strains were isolated from patients with IPD. The ages of the patients ranged from 3 months to 95 years old. The strains were isolated from cerebrospinal fluid, pleural fluid, and blood. The incidence of IPD among patients at HU-USP changed after the introduction of PCV10. The overall incidence of IPD was 3.42 cases per 1000 admissions in the vaccine pre- implementation period and of 2.99 cases per 1000 admissions in the vaccine post-implementation period. The incidence of IPD among children<2 y.o. attended at HU-USP changed significantly after the introduction of PCV10, from 20.30 to 3.97 of incidence. The incidence of PCV10- serotypes decrease from 16.47 to 0.44 in the same age, before and after PC10 implementation, respectively. Moreover, it was possible to realize the sensitivity to penicillin among isolates increased significantly in the post-vaccine period. Data from this study suggest that PCV10 contributed to decrease with PID rate among children less than 2 y.o. The resistance rate among pneumococcal isolates also could be observed since serotypes with greater resistance to beta lactam antibiotics were not easily isolated after vaccination

  11. Ebolavirus Vaccines: Progress in the Fight Against Ebola Virus Disease

    Directory of Open Access Journals (Sweden)

    Xiao-Xin Wu

    2015-11-01

    Full Text Available Ebolaviruses are highly infectious pathogens that cause lethal Ebola virus disease (EVD in humans and non-human primates (NHPs. Due to their high pathogenicity and transmissibility, as well as the potential to be misused as a bioterrorism agent, ebolaviruses would threaten the health of global populations if not controlled. In this review, we describe the origin and structure of ebolaviruses and the development of vaccines from the beginning of the 1980s, including conventional ebolavirus vaccines, DNA vaccines, Ebola virus-like particles (VLPs, vaccinia virus-based vaccines, Venezuelan equine encephalitis virus (VEEV-like replicon particles, Kunjin virus-based vaccine, recombinant Zaire Ebolavirus∆VP30, recombinant cytomegalovirus (CMV-based vaccines, recombinant rabies virus (RABV-based vaccines, recombinant paramyxovirus-based vaccines, adenovirus-based vaccines and vesicular stomatitis virus (VSV-based vaccines. No licensed vaccine or specific treatment is currently available to counteract ebolavirus infection, although DNA plasmids and several viral vector approaches have been evaluated as promising vaccine platforms. These vaccine candidates have been confirmed to be successful in protecting NHPs against lethal infection. Moreover, these vaccine candidates were successfully advanced to clinical trials. The present review provides an update of the current research on Ebola vaccines, with the aim of providing an overview on current prospects in the fight against EVD.

  12. Antibiotic Resistance Determinant-Focused Acinetobacter baumannii Vaccine Designed Using Reverse Vaccinology.

    Science.gov (United States)

    Ni, Zhaohui; Chen, Yan; Ong, Edison; He, Yongqun

    2017-02-21

    As one of the most influential and troublesome human pathogens, Acinetobacter baumannii ( A. baumannii ) has emerged with many multidrug-resistant strains. After collecting 33 complete A. baumannii genomes and 84 representative antibiotic resistance determinants, we used the Vaxign reverse vaccinology approach to predict classical type vaccine candidates against A. baumannii infections and new type vaccine candidates against antibiotic resistance. Our genome analysis identified 35 outer membrane or extracellular adhesins that are conserved among all 33 genomes, have no human protein homology, and have less than 2 transmembrane helices. These 35 antigens include 11 TonB dependent receptors, 8 porins, 7 efflux pump proteins, and 2 fimbrial proteins (FilF and CAM87009.1). CAM86003.1 was predicted to be an adhesin outer membrane protein absent from 3 antibiotic-sensitive strains and conserved in 21 antibiotic-resistant strains. Feasible anti-resistance vaccine candidates also include one extracellular protein (QnrA), 3 RND type outer membrane efflux pump proteins, and 3 CTX-M type β-lactamases. Among 39 β-lactamases, A. baumannii CTX-M-2, -5, and -43 enzymes are predicted as adhesins and better vaccine candidates than other β-lactamases to induce preventive immunity and enhance antibiotic treatments. This report represents the first reverse vaccinology study to systematically predict vaccine antigen candidates against antibiotic resistance for a microbial pathogen.

  13. Third generation DIVA vaccine towards classical swine fever virus. Efficacy in face of maternal immunity

    DEFF Research Database (Denmark)

    Rangelova, Desislava Yordanova

    General purpose and objectives Classical swine fever (CSF) is a highly contagious disease that causes huge economical losses and animal welfare concerns worldwide. Generally, vaccination is an effective and safe method to control the disease. Following vaccination the pig’s immune system develops...... a new DIVA vaccine candidate. The vaccine candidate “CP7E2alf” is intended for either intramuscular vaccination of domestic pig or for bait vaccination of wild boar. In this thesis as part of the clinical testing of the injection vaccine the efficacy of “CP7E2alf” was evaluated in young piglets...

  14. The Last Ten Years of Advancements in Plant-Derived Recombinant Vaccines against Hepatitis B

    Directory of Open Access Journals (Sweden)

    Young Hee Joung

    2016-10-01

    Full Text Available Disease prevention through vaccination is considered to be the greatest contribution to public health over the past century. Every year more than 100 million children are vaccinated with the standard World Health Organization (WHO-recommended vaccines including hepatitis B (HepB. HepB is the most serious type of liver infection caused by the hepatitis B virus (HBV, however, it can be prevented by currently available recombinant vaccine, which has an excellent record of safety and effectiveness. To date, recombinant vaccines are produced in many systems of bacteria, yeast, insect, and mammalian and plant cells. Among these platforms, the use of plant cells has received considerable attention in terms of intrinsic safety, scalability, and appropriate modification of target proteins. Research groups worldwide have attempted to develop more efficacious plant-derived vaccines for over 30 diseases, most frequently HepB and influenza. More inspiring, approximately 12 plant-made antigens have already been tested in clinical trials, with successful outcomes. In this study, the latest information from the last 10 years on plant-derived antigens, especially hepatitis B surface antigen, approaches are reviewed and breakthroughs regarding the weak points are also discussed.

  15. AEROMONAS SALMONICIDA INFECTION IN VACCINATED RAINBOW TROUT

    DEFF Research Database (Denmark)

    Chettri, Jiwan Kumar; Skov, Jakob; Mohammad, Rezkar Jaafar

    In vivo testing of any candidate vaccine is influenced by the choice of challenge method and the external environmental conditions. In the present study, a comparative challenge study was performed to evaluate the efficacy of different vaccines against the bacterial pathogen Aeromonas salmonicida...

  16. Next generation vaccines.

    Science.gov (United States)

    Riedmann, Eva M

    2011-07-01

    In February this year, about 100 delegates gathered for three days in Vienna (Austria) for the Next Generation Vaccines conference. The meeting held in the Vienna Hilton Hotel from 23rd-25th February 2011 had a strong focus on biotech and industry. The conference organizer Jacob Fleming managed to put together a versatile program ranging from the future generation of vaccines to manufacturing, vaccine distribution and delivery, to regulatory and public health issues. Carefully selected top industry experts presented first-hand experience and shared solutions for overcoming the latest challenges in the field of vaccinology. The program also included several case study presentations on novel vaccine candidates in different stages of development. An interactive pre-conference workshop as well as interactive panel discussions during the meeting allowed all delegates to gain new knowledge and become involved in lively discussions on timely, interesting and sometimes controversial topics related to vaccines.

  17. Evaluation of smallpox vaccines using variola neutralization.

    Science.gov (United States)

    Damon, Inger K; Davidson, Whitni B; Hughes, Christine M; Olson, Victoria A; Smith, Scott K; Holman, Robert C; Frey, Sharon E; Newman, Frances; Belshe, Robert B; Yan, Lihan; Karem, Kevin

    2009-08-01

    The search for a 'third'-generation smallpox vaccine has resulted in the development and characterization of several vaccine candidates. A significant barrier to acceptance is the absence of challenge models showing induction of correlates of protective immunity against variola virus. In this light, virus neutralization provides one of few experimental methods to show specific 'in vitro' activity of vaccines against variola virus. Here, we provide characterization of the ability of a modified vaccinia virus Ankara vaccine to induce variola virus-neutralizing antibodies, and we provide comparison with the neutralization elicited by standard Dryvax vaccination.

  18. Molecular signature of high yield (growth influenza a virus reassortants prepared as candidate vaccine seeds.

    Directory of Open Access Journals (Sweden)

    Manojkumar Ramanunninair

    Full Text Available Human influenza virus isolates generally grow poorly in embryonated chicken eggs. Hence, gene reassortment of influenza A wild type (wt viruses is performed with a highly egg adapted donor virus, A/Puerto Rico/8/1934 (PR8, to provide the high yield reassortant (HYR viral 'seeds' for vaccine production. HYR must contain the hemagglutinin (HA and neuraminidase (NA genes of wt virus and one to six 'internal' genes from PR8. Most studies of influenza wt and HYRs have focused on the HA gene. The main objective of this study is the identification of the molecular signature in all eight gene segments of influenza A HYR candidate vaccine seeds associated with high growth in ovo.The genomes of 14 wt parental viruses, 23 HYRs (5 H1N1; 2, 1976 H1N1-SOIV; 2, 2009 H1N1pdm; 2 H2N2 and 12 H3N2 and PR8 were sequenced using the high-throughput sequencing pipeline with big dye terminator chemistry.Silent and coding mutations were found in all internal genes derived from PR8 with the exception of the M gene. The M gene derived from PR8 was invariant in all 23 HYRs underlining the critical role of PR8 M in high yield phenotype. None of the wt virus derived internal genes had any silent change(s except the PB1 gene in X-157. The highest number of recurrent silent and coding mutations was found in NS. With respect to the surface antigens, the majority of HYRs had coding mutations in HA; only 2 HYRs had coding mutations in NA.In the era of application of reverse genetics to alter influenza A virus genomes, the mutations identified in the HYR gene segments associated with high growth in ovo may be of great practical benefit to modify PR8 and/or wt virus gene sequences for improved growth of vaccine 'seed' viruses.

  19. Development of an epitope-based HIV-1 vaccine strategy from HIV-1 lipopeptide to dendritic-based vaccines.

    Science.gov (United States)

    Surenaud, Mathieu; Lacabaratz, Christine; Zurawski, Gérard; Lévy, Yves; Lelièvre, Jean-Daniel

    2017-10-01

    Development of a safe, effective and globally affordable Human Immunodeficiency Virus strain 1 (HIV-1) vaccine offers the best hope for future control of the HIV-1 pandemic. However, with the exception of the recent RV144 trial, which elicited a modest level of protection against infection, no vaccine candidate has shown efficacy in preventing HIV-1 infection or in controlling virus replication in humans. There is also a great need for a successful immunotherapeutic vaccine since combination antiretroviral therapy (cART) does not eliminate the reservoir of HIV-infected cells. But to date, no vaccine candidate has proven to significantly alter the natural history of an individual with HIV-1 infection. Areas covered: For over 25 years, the ANRS (France Recherche Nord&Sud Sida-HIV hépatites) has been committed to an original program combining basic science and clinical research developing an epitope-based vaccine strategy to induce a multiepitopic cellular response against HIV-1. This review describes the evolution of concepts, based on strategies using HIV-1 lipopeptides towards the use of dendritic cell (DC) manipulation. Expert commentary: Understanding the crucial role of DCs in immune responses allowed moving from the non-specific administration of HIV-1 sequences with lipopeptides to DC-based vaccines. These DC-targeting strategies should improve HIV-1 vaccine efficacy.

  20. Characterization and protective efficacy in an animal model of a novel truncated rotavirus VP8 subunit parenteral vaccine candidate.

    Science.gov (United States)

    Xue, Miaoge; Yu, Linqi; Che, Yaojian; Lin, Haijun; Zeng, Yuanjun; Fang, Mujin; Li, Tingdong; Ge, Shengxiang; Xia, Ningshao

    2015-05-21

    The cell-attachment protein VP8* of rotavirus is a potential candidate parenteral vaccine. However, the yield of full-length VP8 protein (VP8*, residues 1-231) expressed in Escherichia coli was low, and a truncated VP8 protein (ΔVP8*, residues 65-231) cannot elicit efficient protective immunity in a mouse model. In this study, tow novel truncated VP8 proteins, VP8-1 (residues 26-231) and VP8-2 (residues 51-231), were expressed in E. coli and evaluated for immunogenicity and protective efficacy, compared with VP8* and ΔVP8*. As well as ΔVP8*, the protein VP8-1 and VP8-2 were successfully expressed in high yield and purified in homogeneous dimeric forms, while the protein VP8* was expressed with lower yield and prone to aggregation and degradation in solution. Although the immunogenicity of the protein VP8*, VP8-1, VP8-2 and ΔVP8* was comparable, immunization of VP8* and VP8-1 elicited significantly higher neutralizing antibody titers than that of VP8-2 and ΔVP8* in mice. Furthermore, when assessed using a mouse maternal antibody model, the efficacy of VP8-1 to protect against rotavirus-induced diarrhea in pups was comparable to that of VP8*, both were dramatically higher than that of VP8-2 and ΔVP8*. Taken together, the novel truncated protein VP8-1, with increased yield, improved homogeneity and high protective efficacy, is a viable candidate for further development of a parenterally administrated prophylactic vaccine against rotavirus infection. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Novel CTL epitopes identified through a Y. pestis proteome-wide analysis in the search for vaccine candidates against plague.

    Science.gov (United States)

    Zvi, Anat; Rotem, Shahar; Zauberman, Ayelet; Elia, Uri; Aftalion, Moshe; Bar-Haim, Erez; Mamroud, Emanuelle; Cohen, Ofer

    2017-10-20

    The causative agent of Plague, Yersinia pestis, is a highly virulent pathogen and a potential bioweapon. Depending on the route of infection, two prevalent occurrences of the disease are known, bubonic and pneumonic. The latter has a high fatality rate. In the absence of a licensed vaccine, intense efforts to develop a safe and efficacious vaccine have been conducted, and humoral-driven subunit vaccines containing the F1 and LcrV antigens are currently under clinical trials. It is well known that a cellular immune response might have an essential additive value to immunity and protection against Y. pestis infection. Nevertheless, very few documented epitopes eliciting a protective T-cell response have been reported. Here, we present a combined high throughput computational and experimental effort towards identification of CD8 T-cell epitopes. All 4067 proteins of Y. pestis were analyzed with state-of-the-art recently developed prediction algorithms aimed at mapping potential MHC class I binders. A compilation of the results obtained from several prediction methods revealed a total of 238,000 peptide candidates, which necessitated downstream filtering criteria. Our previously established and proven approach for enrichment of true positive CTL epitopes, which relies on mapping clusters rich in tandem or overlapping predicted MHC binders ("hotspots"), was applied, as well as considerations of predicted binding affinity. A total of 1532 peptides were tested for their ability to elicit a specific T-cell response by following the production of IFNγ from splenocytes isolated from vaccinated mice. Altogether, the screen resulted in 178 positive responders (11.8%), all novel Y. pestis CTL epitopes. These epitopes span 113 Y. pestis proteins. Substantial enrichment of membrane-associated proteins was detected for epitopes selected from hotspots of predicted MHC binders. These results considerably expand the repertoire of known CTL epitopes in Y. pestis and pave the way to

  2. Production optimisation of a DNA vaccine candidate against ...

    African Journals Online (AJOL)

    Plasmid DNA (pDNA) vaccines are promising means to prevent and treat infectious diseases, such as leishmaniasis, but immunisation protocols require large amounts of supercoiled plasmid DNA (scpDNA). Although pDNA can be produced at a reasonable cost in bioreactors; this scale of production may not be the best ...

  3. Hepatitis B Virus Vaccine: The Nigerian Story | Odusanya | Journal ...

    African Journals Online (AJOL)

    Hepatitis B (HBV) virus in endemic in Nigeria. Infection is acquired mainly in childhood through horizontal transmission. The infection is preventable by vaccination. Universal childhood vaccination against the infection started in Nigeria less than ten years. Hepatitis B vaccine coverage in Nigeria is 41%, though now it has ...

  4. Subunit vaccine candidates against Aeromonas salmonicida in rainbow trout Oncorhynchus mykiss.

    Science.gov (United States)

    Marana, Moonika Haahr; Jørgensen, Louise von Gersdorff; Skov, Jakob; Chettri, Jiwan Kumar; Holm Mattsson, Andreas; Dalsgaard, Inger; Kania, Per Walter; Buchmann, Kurt

    2017-01-01

    Aeromonas salmonicida subsp. salmonicida is the etiological agent of furunculosis and a major fish health problem in salmonid aquaculture worldwide. Injection vaccination with commercial mineral oil-adjuvanted bacterin vaccines has been partly successful in preventing the disease but in Danish rainbow trout (Oncorhynchus mykiss, Walbaum) aquaculture furunculosis outbreaks still occur. In this study we tested the efficacy of experimental subunit vaccines against A. salmonicida infection in rainbow trout. We utilized in silico screening of the proteome of A. salmonicida subsp. salmonicida strain A449 and identified potential protective protein antigens that were tested by in vivo challenge trial. A total of 14 proteins were recombinantly expressed in Escherichia coli and prepared in 3 different subunit vaccine combinations to immunize 3 groups of rainbow trout by intraperitoneal (i.p.) injection. The fish were exposed to virulent A. salmonicida 7 weeks after immunization. To assess the efficacy of the subunit vaccines we evaluated the immune response in fish after immunization and challenge infection by measuring the antibody levels and monitoring the survival of fish in different groups. The survival of fish at 3 weeks after challenge infection showed that all 3 groups of fish immunized with 3 different protein combinations exhibited significantly lower mortalities (17-30%) compared to the control groups (48% and 56%). The ELISA results revealed significantly elevated antibody levels in fish against several protein antigens, which in some cases were positively correlated to the survival.

  5. Construction and evaluation of novel rhesus monkey adenovirus vaccine vectors.

    Science.gov (United States)

    Abbink, Peter; Maxfield, Lori F; Ng'ang'a, David; Borducchi, Erica N; Iampietro, M Justin; Bricault, Christine A; Teigler, Jeffrey E; Blackmore, Stephen; Parenteau, Lily; Wagh, Kshitij; Handley, Scott A; Zhao, Guoyan; Virgin, Herbert W; Korber, Bette; Barouch, Dan H

    2015-02-01

    Adenovirus vectors are widely used as vaccine candidates for a variety of pathogens, including HIV-1. To date, human and chimpanzee adenoviruses have been explored in detail as vaccine vectors. The phylogeny of human and chimpanzee adenoviruses is overlapping, and preexisting humoral and cellular immunity to both are exhibited in human populations worldwide. More distantly related adenoviruses may therefore offer advantages as vaccine vectors. Here we describe the primary isolation and vectorization of three novel adenoviruses from rhesus monkeys. The seroprevalence of these novel rhesus monkey adenovirus vectors was extremely low in sub-Saharan Africa human populations, and these vectors proved to have immunogenicity comparable to that of human and chimpanzee adenovirus vaccine vectors in mice. These rhesus monkey adenoviruses phylogenetically clustered with the poorly described adenovirus species G and robustly stimulated innate immune responses. These novel adenoviruses represent a new class of candidate vaccine vectors. Although there have been substantial efforts in the development of vaccine vectors from human and chimpanzee adenoviruses, far less is known about rhesus monkey adenoviruses. In this report, we describe the isolation and vectorization of three novel rhesus monkey adenoviruses. These vectors exhibit virologic and immunologic characteristics that make them attractive as potential candidate vaccine vectors for both HIV-1 and other pathogens. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  6. Comparative genomic analysis of Brucella abortus vaccine strain 104M reveals a set of candidate genes associated with its virulence attenuation.

    Science.gov (United States)

    Yu, Dong; Hui, Yiming; Zai, Xiaodong; Xu, Junjie; Liang, Long; Wang, Bingxiang; Yue, Junjie; Li, Shanhu

    2015-01-01

    The Brucella abortus strain 104M, a spontaneously attenuated strain, has been used as a vaccine strain in humans against brucellosis for 6 decades in China. Despite many studies, the molecular mechanisms that cause the attenuation are still unclear. Here, we determined the whole-genome sequence of 104M and conducted a comprehensive comparative analysis against the whole genome sequences of the virulent strain, A13334, and other reference strains. This analysis revealed a highly similar genome structure between 104M and A13334. The further comparative genomic analysis between 104M and A13334 revealed a set of genes missing in 104M. Some of these genes were identified to be directly or indirectly associated with virulence. Similarly, a set of mutations in the virulence-related genes was also identified, which may be related to virulence alteration. This study provides a set of candidate genes associated with virulence attenuation in B.abortus vaccine strain 104M.

  7. Ebolavirus Vaccines: Progress in the Fight Against Ebola Virus Disease.

    Science.gov (United States)

    Wu, Xiao-Xin; Yao, Hang-Ping; Wu, Nan-Ping; Gao, Hai-Nv; Wu, Hai-Bo; Jin, Chang-Zhong; Lu, Xiang-Yun; Xie, Tian-Shen; Li, Lan-Juan

    2015-01-01

    Ebolaviruses are highly infectious pathogens that cause lethal Ebola virus disease (EVD) in humans and non-human primates (NHPs). Due to their high pathogenicity and transmissibility, as well as the potential to be misused as a bioterrorism agent, ebolaviruses would threaten the health of global populations if not controlled. In this review, we describe the origin and structure of ebolaviruses and the development of vaccines from the beginning of the 1980s, including conventional ebolavirus vaccines, DNA vaccines, Ebola virus-like particles (VLPs), vaccinia virus-based vaccines, Venezuelan equine encephalitis virus (VEEV)-like replicon particles, Kunjin virus-based vaccine, recombinant Zaire Ebolavirusx2206;VP30, recombinant cytomegalovirus (CMV)-based vaccines, recombinant rabies virus (RABV)-based vaccines, recombinant paramyxovirus-based vaccines, adenovirus-based vaccines and vesicular stomatitis virus (VSV)-based vaccines. No licensed vaccine or specific treatment is currently available to counteract ebolavirus infection, although DNA plasmids and several viral vector approaches have been evaluated as promising vaccine platforms. These vaccine candidates have been confirmed to be successful in protecting NHPs against lethal infection. Moreover, these vaccine candidates were successfully advanced to clinical trials. The present review provides an update of the current research on Ebola vaccines, with the aim of providing an overview on current prospects in the fight against EVD. © 2015 The Author(s) Published by S. Karger AG, Basel.

  8. Prophylactic Hepatitis E Vaccine.

    Science.gov (United States)

    Zhang, Jun; Zhao, Qinjian; Xia, Ningshao

    2016-01-01

    Hepatitis E has been increasingly recognized as an underestimated global disease burden in recent years. Subpopulations with more serious infection-associated damage or death include pregnant women, patients with basic liver diseases, and elderly persons. Vaccine would be the most effective means for prevention of HEV infection. The lack of an efficient cell culture system for HEV makes the development of classic inactive or attenuated vaccine infeasible. Hence, the recombinant vaccine approaches are explored deeply. The neutralizing sites are located almost exclusively in the capsid protein, pORF2, of the virion. Based on pORF2, many vaccine candidates showed potential of protecting primate animals; two of them were tested in human and evidenced to be well tolerated in adults and highly efficacious in preventing hepatitis E. The world's first hepatitis E vaccine, Hecolin ® (HEV 239 vaccine), was licensed in China and launched in 2012.

  9. A recombinant pseudorabies virus co-expressing capsid proteins precursor P1-2A of FMDV and VP2 protein of porcine parvovirus: a trivalent vaccine candidate.

    Science.gov (United States)

    Hong, Qi; Qian, Ping; Li, Xiang-Min; Yu, Xiao-Lan; Chen, Huan-Chun

    2007-11-01

    Pseudorabies (PR), foot-and-mouth disease (FMD), and porcine parvovirus disease are three important infectious diseases in swine worldwide. The gene-deleted pseudorabies virus (PRV) has been used as a live-viral vector to develop multivalent genetic engineering vaccine. In this study, a recombinant PRV, which could co-express protein precursor P1-2A of FMDV and VP2 protein of PPV, was constructed using PRV TK(-)/gE(-)/LacZ(+) mutant as the vector. After homologous recombination and plaque purification, recombinant virus PRV TK(-)/gE(-)/P1-2A-VP2 was acquired and identified. Immunogenicity, safety of the recombinant PRV and its protection against PRV were confirmed in a mouse model by indirect ELISA and serum neutralization test. The results show that the recombinant PRV is a candidate vaccine strain to develop a novel trivalent vaccine against PRV, FMDV and PPV in swine.

  10. Immunogenicity and in vitro Protective Efficacy of a Recombinant Multistage Plasmodium falciparum Candidate Vaccine

    Science.gov (United States)

    Shi, Ya Ping; Hasnain, Seyed E.; Sacci, John B.; Holloway, Brian P.; Fujioka, Hisashi; Kumar, Nirbhay; Wohlhueter, Robert; Hoffman, Stephen L.; Collins, William E.; Lal, Altaf A.

    1999-02-01

    Compared with a single-stage antigen-based vaccine, a multistage and multivalent Plasmodium falciparum vaccine would be more efficacious by inducing "multiple layers" of immunity. We have constructed a synthetic gene that encodes for 12 B cell, 6 T cell proliferative, and 3 cytotoxic T lymphocyte epitopes derived from 9 stage-specific P. falciparum antigens corresponding to the sporozoite, liver, erythrocytic asexual, and sexual stages. The gene was expressed in the baculovirus system, and a 41-kDa antigen, termed CDC/NIIMALVAC-1, was purified. Immunization in rabbits with the purified protein in the presence of different adjuvants generated antibody responses that recognized vaccine antigen, linear peptides contained in the vaccine, and all stages of P. falciparum. In vitro assays of protection revealed that the vaccine-elicited antibodies strongly inhibited sporozoite invasion of hepatoma cells and growth of blood-stage parasites in the presence of monocytes. These observations demonstrate that a multicomponent, multistage malaria vaccine can induce immune responses that inhibit parasite development at multiple stages. The rationale and approach used in the development of a multicomponent P. falciparum vaccine will be useful in the development of a multispecies human malaria vaccine and vaccines against other infectious diseases.

  11. Cost of production of live attenuated dengue vaccines: a case study of the Instituto Butantan, Sao Paulo, Brazil.

    Science.gov (United States)

    Mahoney, R T; Francis, D P; Frazatti-Gallina, N M; Precioso, A R; Raw, I; Watler, P; Whitehead, P; Whitehead, S S

    2012-07-06

    A vaccine to prevent dengue disease is urgently needed. Fortunately, a few tetravalent candidate vaccines are in the later stages of development and show promise. But, if the cost of these candidates is too high, their beneficial potential will not be realized. The price of a vaccine is one of the most important factors affecting its ultimate application in developing countries. In recent years, new vaccines such as those for human papilloma virus and pneumococcal disease (conjugate vaccine) have been introduced with prices in developed countries exceeding $50 per dose. These prices are above the level affordable by developing countries. In contrast, other vaccines such as those against Japanese encephalitis (SA14-14-2 strain vaccine) and meningitis type A have prices in developing countries below one dollar per dose, and it is expected that their introduction and use will proceed more rapidly. Because dengue disease is caused by four related viruses, vaccines must be able to protect against all four. Although there are several live attenuated dengue vaccine candidates under clinical evaluation, there remains uncertainty about the cost of production of these tetravalent vaccines, and this uncertainty is an impediment to rapid progress in planning for the introduction and distribution of dengue vaccines once they are licensed. We have undertaken a detailed economic analysis, using standard industrial methodologies and applying generally accepted accounting practices, of the cost of production of a live attenuated vaccine, originally developed at the US National Institutes of Health (National Institute of Allergy and Infectious Diseases), to be produced at the Instituto Butantan in Sao Paulo, Brazil. We determined direct costs of materials, direct costs of personnel and labor, indirect costs, and depreciation. These were analyzed assuming a steady-state production of 60 million doses per year. Although this study does not seek to compute the price of the final

  12. Pricing of new vaccines.

    Science.gov (United States)

    Lee, Bruce Y; McGlone, Sarah M

    2010-08-01

    New vaccine pricing is a complicated process that could have substantial long-standing scientific, medical, and public health ramifications. Pricing can have a considerable impact on new vaccine adoption and, thereby, either culminate or thwart years of research and development and public health efforts. Typically, pricing strategy consists of the following ten components: 1. Conduct a target population analysis; 2. Map potential competitors and alternatives; 3. Construct a vaccine target product profile (TPP) and compare it to projected or actual TPPs of competing vaccines; 4. Quantify the incremental value of the new vaccine's characteristics; 5. Determine vaccine positioning in the marketplace; 6. Estimate the vaccine price-demand curve; 7. Calculate vaccine costs (including those of manufacturing, distribution, and research and development); 8. Account for various legal, regulatory, third party payer, and competitor factors; 9. Consider the overall product portfolio; 10. Set pricing objectives; 11. Select pricing and pricing structure. While the biomedical literature contains some studies that have addressed these components, there is still considerable room for more extensive evaluation of this important area.

  13. Hendra and Nipah viruses: pathogenesis, animal models and recent breakthroughs in vaccination

    Directory of Open Access Journals (Sweden)

    Weingartl HM

    2015-09-01

    Full Text Available Hana M Weingartl National Centre for Foreign Animal Disease, Canadian Food Inspection Agency, Winnipeg, MB, Canada Abstract: Hendra and Nipah viruses are two highly pathogenic zoonotic members of the genus Henipavirus, family Paramyxoviridae, requiring work under biosafety level 4 conditions due to a lack of effective therapy and human vaccines. Several vaccine candidates were protective in animal models: recombinant vaccinia virus expressing Nipah virus (NiV F and G proteins in hamsters against NiV; recombinant ALVAC–NiV F and G in swine against NiV; recombinant Hendra virus (HeV soluble G protein (sGHeV against HeV and NiV in cats, ferrets, horses, and African green monkeys (AGM; recombinant vesicular stomatitis virus-based vectors expressing NiV F or G against NiV in hamsters and ferrets; measles virus-based NiV G vaccine candidate in hamsters and AGMs against NiV; and adenoassociated virus expressing NiG protein, which protected hamsters against NiV. The sGHeV was licensed for use in horses (Equivac HeV® in 2012. It is the first vaccine candidate licensed against a biosafety level 4 agent. With the development of suitable animal models (ferret, hamster and, importantly, AGM, progress can be made toward development of a human vaccine.Keywords: henipavirus, equine, swine, human infection, animal models, vaccine candidates

  14. New vaccines against otitis media: projected benefits and cost-effectiveness.

    Science.gov (United States)

    O'Brien, Megan A; Prosser, Lisa A; Paradise, Jack L; Ray, G Thomas; Kulldorff, Martin; Kurs-Lasky, Marcia; Hinrichsen, Virginia L; Mehta, Jyotsna; Colborn, D Kathleen; Lieu, Tracy A

    2009-06-01

    New vaccines that offer protection against otitis media caused by nontypeable Haemophilus influenzae and by Moraxella catarrhalis are under development. However, the potential health benefits and economic effects of such candidate vaccines have not been systematically assessed. We created a computerized model to compare the projected benefits and costs of (1) the currently available 7-valent pneumococcal conjugate vaccine, (2) a candidate pneumococcal-nontypeable H influenzae vaccine that has been tested in Europe, (3) a hypothetical pneumococcal-nontypeable H influenzae-Moraxella vaccine, and (4) no vaccination. The clinical probabilities of acute otitis media and of otitis media with effusion were generated from multivariate analyses of data from 2 large health maintenance organizations and from the Pittsburgh Child Development/Otitis Media Study cohort. Other probabilities, costs, and quality-of-life values were derived from published and unpublished sources. The base-case analysis assumed vaccine dose costs of $65 for the 7-valent pneumococcal conjugate vaccine, $100 for the pneumococcal-nontypeable H influenzae vaccine, and $125 for the pneumococcal-nontypeable H influenzae-Moraxella vaccine. With no vaccination, we projected that 13.7 million episodes of acute otitis media would occur annually in US children aged 0 to 4 years, at an annual cost of $3.8 billion. The 7-valent pneumococcal conjugate vaccine was projected to prevent 878,000 acute otitis media episodes, or 6.4% of those that would occur with no vaccination; the corresponding value for the pneumococcal-nontypeable H influenzae vaccine was 3.7 million (27%) and for the pneumococcal-nontypeable H influenzae-Moraxella vaccine was 4.2 million (31%). Using the base-case vaccine costs, pneumococcal-nontypeable H influenzae vaccine use would result in net savings compared with nontypeable 7-valent pneumococcal conjugate use. Conversely, pneumococcal-nontypeable H influenzae-Moraxella vaccine use would not

  15. Comparative evaluation of the protective efficacy of two formulations of a recombinant Chlamydia abortus subunit candidate vaccine in a mouse model.

    Science.gov (United States)

    Pan, Qing; Pais, Roshan; Ohandjo, Adaugo; He, Cheng; He, Qing; Omosun, Yusuf; Igietseme, J U; Eko, F O

    2015-04-08

    Chlamydia abortus (C. abortus) is the causative agent of ovine enzootic abortion (OEA) and poses a zoonotic risk to pregnant women. Current live attenuated 1B vaccines are efficacious but cause disease in vaccinated animals and inactivated vaccines are only marginally protective. We tested the ability of a new C. abortus subunit vaccine candidate based on the conserved and immunogenic polymorphic membrane protein D (Pmp18D) formulated in CpG1826+FL (Fms-like tyrosine kinase 3 Ligand; Flt3L) or Vibrio cholerae ghosts (VCG) to induce innate and cross protective immunity against genital C. abortus infection. We found that delivery of rPmp18D with VCG was more effective than with CpG+FL in up-regulating the expression of molecules critically involved in T cell activation and differentiation, including MHC II, CD40, CD80, and CD86, activation of TLRs and NLRP3 inflammasome engagement, and secretion of IL-1β and TNF-α but not IL-10 and IL-4. rVCG-Pmp18D-immunized mice elicited more robust antigen-specific IFN-γ, IgA and IgG2c antibody responses compared to CpG+FL-delivered rPmp18D. Based on the number of mice with positive vaginal cultures, length of vaginal shedding, and number of inclusion forming units recovered following challenge with the heterologous C. abortus strain B577, vaccine delivery with VCG induced superior protective immunity than delivery with a combination of CpG1826 and FL, a nasal DC-targeting adjuvant. These results demonstrate that the ability of VCG to enhance protective immunity against genital C. abortus infection is superior to that of CpG+FL adjuvants. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Progress in Brucella vaccine development

    Science.gov (United States)

    YANG, Xinghong; SKYBERG, Jerod A.; CAO, Ling; CLAPP, Beata; THORNBURG, Theresa; PASCUAL, David W.

    2012-01-01

    Brucella spp. are zoonotic, facultative intracellular pathogens, which cause animal and human disease. Animal disease results in abortion of fetuses; in humans, it manifests flu-like symptoms with an undulant fever, with osteoarthritis as a common complication of infection. Antibiotic regimens for human brucellosis patients may last several months and are not always completely effective. While there are no vaccines for humans, several licensed live Brucella vaccines are available for use in livestock. The performance of these animal vaccines is dependent upon the host species, dose, and route of immunization. Newly engineered live vaccines, lacking well-defined virulence factors, retain low residual virulence, are highly protective, and may someday replace currently used animal vaccines. These also have possible human applications. Moreover, due to their enhanced safety and efficacy in animal models, subunit vaccines for brucellosis show great promise for their application in livestock and humans. This review summarizes the progress of brucellosis vaccine development and presents an overview of candidate vaccines. PMID:23730309

  17. Current status of flavivirus vaccines.

    Science.gov (United States)

    Barrett, A D

    2001-12-01

    Although there are approximately 68 flaviviruses recognized, vaccines have been developed to control very few human flavivirus diseases. Licensed live attenuated vaccines have been developed for yellow fever (strain 17D) and Japanese encephalitis (strain SA14-14-2) viruses, and inactivated vaccines have been developed for Japanese encephalitis and tick-borne encephalitis viruses. The yellow fever live attenuated 17D vaccine is one of the most efficacious and safe vaccines developed to date and has been used to immunize more than 300 million people. A number of experimental vaccines are being developed, most notably for dengue. Candidate tetravalent live attenuated dengue vaccines are undergoing clinical trials. Other vaccines are being developed using reverse genetics, DNA vaccines, and recombinant immunogens. In addition, the yellow fever 17D vaccine has been used as a backbone to generate chimeric viruses containing the premembrane and envelope protein genes from other flaviviruses. The "Chimerivax" platform has been used to construct chimeric Japanese encephalitis and dengue viruses that are in different phases of development. Similar strategies are being used by other laboratories.

  18. Vaccines for viral and parasitic diseases produced with baculovirus vectors

    NARCIS (Netherlands)

    Oers, van M.M.

    2006-01-01

    The baculovirus¿insect cell expression system is an approved system for the production of viral antigens with vaccine potential for humans and animals and has been used for production of subunit vaccines against parasitic diseases as well. Many candidate subunit vaccines have been expressed in this

  19. Chimeric classical swine fever (CSF)-Japanese encephalitis (JE) viral replicon as a non-transmissible vaccine candidate against CSF and JE infections.

    Science.gov (United States)

    Yang, Zhenhua; Wu, Rui; Li, Robert W; Li, Ling; Xiong, Zhongliang; Zhao, Haizhong; Guo, Deyin; Pan, Zishu

    2012-04-01

    A trans-complemented chimeric CSF-JE virus replicon was constructed using an infectious cDNA clone of the CSF virus (CSFV) Alfort/187 strain. The CSFV E2 gene was deleted, and a fragment containing the region encoding a truncated envelope protein (tE, amino acid 292-402, domain III) of JE virus (JEV) was inserted into the resultant plasmid, pA187delE2, to generate the recombinant cDNA clone pA187delE2/JEV-tE. Porcine kidney 15 (PK15) cells that constitutively express the CSFV E2p7 proteins were then transfected with in vitro-transcribed RNA from pA187delE2/JEV-tE. As a result, the chimeric CSF-JE virus replicon particle (VRP), rv187delE2/JEV-tE, was rescued. In a mouse model, immunization with the chimeric CSF-JE VRP induced strong production of JEV-specific antibody and conferred protection against a lethal JEV challenge. Pigs immunized with CSF-JE VRP displayed strong anti-CSFV and anti-JEV antibody responses and protection against CSFV and JEV challenge infections. Our evidence suggests that E2-complemented CSF-JE VRP not only has potential as a live-attenuated non-transmissible vaccine candidate against CSF and JE but also serves as a potential DIVA (Differentiating Infected from Vaccinated Animals) vaccine for CSF in pigs. Together, our data suggest that the non-transmissible chimeric VRP expressing foreign antigenic proteins may represent a promising strategy for bivalent DIVA vaccine design. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Next-Generation Dengue Vaccines: Novel Strategies Currently Under Development

    OpenAIRE

    Anna P. Durbin; Stephen S. Whitehead

    2011-01-01

    Dengue has become the most important arboviral infection worldwide with more than 30 million cases of dengue fever estimated to occur each year. The need for a dengue vaccine is great and several live attenuated dengue candidate vaccines are proceeding through clinical evaluation. The need to induce a balanced immune response against all four DENV serotypes with a single vaccine has been a challenge for dengue vaccine developers. A live attenuated DENV chimeric vaccine produced by Sanofi Past...

  1. Vaccination coverage among social and healthcare workers in ten countries of Samu-social international sites.

    Science.gov (United States)

    Marshall, Esaie; Salmon, Dominique; Bousfiha, Nadia; Togola, Yacouba; Ouedraogo, François; Santantonio, Maud; Dieng, Coumba Khadidja; Tartière, Suzanne; Emmanuelli, Xavier

    2017-09-18

    We aim to determine the vaccination coverage of social and healthcare workers in International sites of Samusocial, providing emergency care to homeless people, and to assess factors associated with having received necessary doses at adulthood. Data on immunization coverage of social and healthcare workers were provided by a cross-sectional survey, conducted from February to April 2015 among 252 Samusocial workers in 10 countries. Vaccination status and characteristics of participants were collected through a self-administered questionnaire. Prevalence rate ratio (PRR) of vaccination status was calculated using Poisson regression models. Among 252 Samusocial social and health workers who felt a questionnaire, median age was 39years, 42.1% were female, 88.9% were in contact with homeless beneficiaries (19.1% health workers). Overall, 90.1% of Samusocial staff felt adult vaccinations was useful and 70.2% wished to receive booster doses in future. Vaccination coverage at adulthood was satisfactory for diphtheria and poliomyelitis (96%), but low for influenza (20.8%), meningococcus (50.5%), hepatitis B (56.3%), yellow fever (58.1%), measles (81.3%) and pertussis (90.7%). The main reasons for not having received vaccination booster doses were forgetting the dates of booster doses (38.4%) and not having received the information (13.5%). In adjusted analysis, prevalence of up-to-date for vaccination schedule was 35% higher among health workers than among social workers (aPRR=1.35, 95%CI: 1.01-1.82, P=0.05) and was 56% higher among workers who had a documentary evidence of vaccination than in those who did not (aPRR=1.56, 95%CI: 1.19-2.02, P=0.001). The Samusocial International workers vaccine coverage at adulthood was insufficient and disparate by region. It is necessary to strengthen the outreach of this staff and increase immunization policy for hepatitis B, diphtheria, tetanus, and measles, as well as for yellow fever, rabies and meningococcal ACYW135 vaccines in at

  2. Dengue vaccines: Challenges, development, current status and prospects

    Directory of Open Access Journals (Sweden)

    A Ghosh

    2015-01-01

    Full Text Available Infection with dengue virus (DENV is the most rapidly spreading mosquito-borne viral disease in the world. The clinical spectrum of dengue, caused by any of the four serotypes of DENV, ranges from mild self-limiting dengue fever to severe dengue, in the form dengue hemorrhagic fever (DHF and dengue shock syndrome (DSS. Increased rates of hospitalization due to severe dengue, during outbreaks, result in massive economic losses and strained health services. In the absence of specific antiviral therapy, control of transmission of DENV by vector management is the sole method available for decreasing dengue-associated morbidity. Since vector control strategies alone have not been able to satisfactorily achieve reduction in viral transmission, the implementation of a safe, efficacious and cost-effective dengue vaccine as a supplementary measure is a high public health priority. However, the unique and complex immunopathology of dengue has complicated vaccine development. Dengue vaccines have also been challenged by critical issues like lack of animal models for the disease and absence of suitable markers of protective immunity. Although no licensed dengue vaccine is yet available, several vaccine candidates are under phases of development, including live attenuated virus vaccines, live chimeric virus vaccines, inactivated virus vaccines, subunit vaccines, DNA vaccines and viral-vectored vaccines. Although some vaccine candidates have progressed from animal trials to phase II and III in humans, a number of issues regarding implementation of dengue vaccine in countries like India still need to be addressed. Despite the current limitations, collaborative effects of regulatory bodies like World Health Organization with vaccine manufacturers and policy makers, to facilitate vaccine development and standardize field trials can make a safe and efficacious dengue vaccine a reality in near future.

  3. Status of prophylactic and therapeutic genital herpes vaccines.

    Science.gov (United States)

    Awasthi, Sita; Friedman, Harvey M

    2014-06-01

    A half billion people have genital herpes infections worldwide. Approximately one-fifth of American women between ages 14 and 49 are HSV-2 seropositive. The development of an effective genital herpes vaccine is a global health necessity based on the mental anguish genital herpes causes for some individuals, the fact that pregnant women with genital herpes risk transmitting infection to their newborn children, and the observation that HSV-2 infection is associated with a 3-fold to 4-fold increased probability of HIV acquisition. We review the strengths and limitations of preclinical animal models used to assess genital herpes vaccine candidates and the goals of prophylactic and therapeutic vaccines. We also discuss the current pipeline of vaccine candidates and lessons learned from past clinical trials that serve as a stimulus for new strategies, study designs and endpoint determinations. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Loss of confidence in vaccines following media reports of infant deaths after hepatitis B vaccination in China.

    Science.gov (United States)

    Yu, Wenzhou; Liu, Dawei; Zheng, Jingshan; Liu, Yanmin; An, Zhijie; Rodewald, Lance; Zhang, Guomin; Su, Qiru; Li, Keli; Xu, Disha; Wang, Fuzhen; Yuan, Ping; Xia, Wei; Ning, Guijun; Zheng, Hui; Chu, Yaozhu; Cui, Jian; Duan, Mengjuan; Hao, Lixin; Zhou, Yuqing; Wu, Zhenhua; Zhang, Xuan; Cui, Fuqiang; Li, Li; Wang, Huaqing

    2016-04-01

    China reduced hepatitis B virus (HBV) infection by 90% among children under 5 years old with safe and effective hepatitis B vaccines (HepB). In December 2013, this success was threatened by widespread media reports of infant deaths following HepB administration. Seventeen deaths and one case of anaphylactic shock following HBV vaccination had been reported. We conducted a telephone survey to measure parental confidence in HepB in eleven provinces at four points in time; reviewed maternal HBV status and use of HepB for newborns in birth hospitals in eight provinces before and after the event; and monitored coverage with hepatitis B vaccine and other programme vaccines in ten provinces. HepB from the implicated company was suspended during the investigation, which showed that the deaths were not caused by HepB vaccination. Before the event, 85% respondents regarded domestic vaccines as safe, decreasing to 26.7% during the event. During the height of the crisis, 30% of parents reported being hesitant to vaccinate and 18.4% reported they would refuse HepB. Use of HepB in the monitored provinces decreased by 18.6%, from 53 653 doses the week before the event to 43 688 doses during the week that Biokangtai HepB was suspended. Use of HepB within the first day of life decreased by 10% among infants born to HBsAg-negative mothers, and by 6% among infants born to HBsAg-positive mothers. Vaccine refusal and HepB birth dose rates returned to baseline within 2 months; confidence increased, but remained below baseline. The HBV vaccine event resulted in the suspension of a safe vaccine, which was associated with a decline of parental confidence, and refusal of vaccination. Suspension of a vaccine can lead to loss of confidence that is difficult to recover. Timely and credible investigation, accompanied by proactive outreach to stakeholders and the media, may help mitigate negative impact of future coincidental adverse events following immunization. © The Author 2016; all rights

  5. The candidate TB vaccine, MVA85A, induces highly durable Th1 responses.

    Directory of Open Access Journals (Sweden)

    Michele Tameris

    Full Text Available Vaccination against tuberculosis (TB should provide long-term protective immunity against Mycobacterium tuberculosis (M.tb. The current TB vaccine, Bacille Calmette-Guerin (BCG, protects against disseminated childhood TB, but protection against lung TB in adolescents and adults is variable and mostly poor. One potential reason for the limited durability of protection may be waning of immunity through gradual attrition of BCG-induced T cells. We determined if a MVA85A viral-vector boost could enhance the durability of mycobacteria-specific T cell responses above those induced by BCG alone.We describe a long-term follow-up study of persons previously vaccinated with MVA85A. We performed a medical history and clinical examination, a tuberculin skin test and measured vaccine-specific T cell responses in persons previously enrolled as adults, adolescents, children or infants into three different Phase II trials, between 2005 and 2011.Of 252 potential participants, 183 (72.6% consented and completed the study visit. Vaccine-induced Ag85A-specific CD4+ T cell responses were remarkably persistent in healthy, HIV-uninfected adults, adolescents, children and infants, up to 6 years after MVA85A vaccination. Specific CD4+ T cells expressed surface markers consistent with either CD45RA-CCR7+ central memory or CD45RA-CCR7- effector memory T cells. Similarly durable Ag85A-specific CD4+ T cell responses were detected in HIV-infected persons who were on successful antiretroviral therapy when MVA85A was administered. By contrast, Ag85A-specific CD4+ T cell frequencies in untreated MVA85A-vaccinated HIV-infected persons were mostly undetectable 3-5 years after vaccination.MVA85A induces remarkably durable T cell responses in immunocompetent persons. However, results from a recent phase IIb trial of MVA85A, conducted in infants from the same geographic area and study population, showed no vaccine efficacy, suggesting that these durable T cell responses do not

  6. Live attenuated vaccines: Historical successes and current challenges.

    Science.gov (United States)

    Minor, Philip D

    2015-05-01

    Live attenuated vaccines against human viral diseases have been amongst the most successful cost effective interventions in medical history. Smallpox was declared eradicated in 1980; poliomyelitis is nearing global eradication and measles has been controlled in most parts of the world. Vaccines function well for acute diseases such as these but chronic infections such as HIV are more challenging for reasons of both likely safety and probable efficacy. The derivation of the vaccines used has in general not been purely rational except in the sense that it has involved careful clinical trials of candidates and subsequent careful follow up in clinical use; the identification of the candidates is reviewed. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

  7. Large animal models for vaccine development and testing.

    Science.gov (United States)

    Gerdts, Volker; Wilson, Heather L; Meurens, Francois; van Drunen Littel-van den Hurk, Sylvia; Wilson, Don; Walker, Stewart; Wheler, Colette; Townsend, Hugh; Potter, Andrew A

    2015-01-01

    The development of human vaccines continues to rely on the use of animals for research. Regulatory authorities require novel vaccine candidates to undergo preclinical assessment in animal models before being permitted to enter the clinical phase in human subjects. Substantial progress has been made in recent years in reducing and replacing the number of animals used for preclinical vaccine research through the use of bioinformatics and computational biology to design new vaccine candidates. However, the ultimate goal of a new vaccine is to instruct the immune system to elicit an effective immune response against the pathogen of interest, and no alternatives to live animal use currently exist for evaluation of this response. Studies identifying the mechanisms of immune protection; determining the optimal route and formulation of vaccines; establishing the duration and onset of immunity, as well as the safety and efficacy of new vaccines, must be performed in a living system. Importantly, no single animal model provides all the information required for advancing a new vaccine through the preclinical stage, and research over the last two decades has highlighted that large animals more accurately predict vaccine outcome in humans than do other models. Here we review the advantages and disadvantages of large animal models for human vaccine development and demonstrate that much of the success in bringing a new vaccine to market depends on choosing the most appropriate animal model for preclinical testing. © The Author 2015. Published by Oxford University Press on behalf of the Institute for Laboratory Animal Research. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  8. An optimized, fast-to-perform mouse lung infection model with the human pathogen Chlamydia trachomatis for in vivo screening of antibiotics, vaccine candidates and modified host-pathogen interactions.

    Science.gov (United States)

    Dutow, Pavel; Wask, Lea; Bothe, Miriam; Fehlhaber, Beate; Laudeley, Robert; Rheinheimer, Claudia; Yang, Zhangsheng; Zhong, Guangming; Glage, Silke; Klos, Andreas

    2016-03-01

    Chlamydia trachomatis causes sexually transmitted diseases with infertility, pelvic inflammatory disease and neonatal pneumonia as complications. The duration of urogenital mouse models with the strict mouse pathogen C. muridarum addressing vaginal shedding, pathological changes of the upper genital tract or infertility is rather long. Moreover, vaginal C. trachomatis application usually does not lead to the complications feared in women. A fast-to-perform mouse model is urgently needed to analyze new antibiotics, vaccine candidates, immune responses (in gene knockout animals) or mutants of C. trachomatis. To complement the valuable urogenital model with a much faster and quantifiable screening method, we established an optimized lung infection model for the human intracellular bacterium C. trachomatis serovar D (and L2) in immunocompetent C57BL/6J mice. We demonstrated its usefulness by sensitive determination of antibiotic effects characterizing advantages and limitations achievable by early or delayed short tetracycline treatment and single-dose azithromycin application. Moreover, we achieved partial acquired protection in reinfection with serovar D indicating usability for vaccine studies, and showed a different course of disease in absence of complement factor C3. Sensitive monitoring parameters were survival rate, body weight, clinical score, bacterial load, histological score, the granulocyte marker myeloperoxidase, IFN-γ, TNF-α, MCP-1 and IL-6. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Minimizing pain during childhood vaccination injections: improving adherence to vaccination schedules

    Directory of Open Access Journals (Sweden)

    Eden LM

    2014-09-01

    Full Text Available Lacey M Eden, Janelle LB Macintosh, Karlen E Luthy, Renea L Beckstrand College of Nursing, Brigham Young University, Provo, UT, USA Abstract: Pain experienced in childhood can lead to long-term and psychologically detrimental effects. Unfortunately, the most common pain experienced in childhood is caused by vaccinations and may lead to non-adherence to the recommended vaccination schedule. As a result, it is the health care provider's responsibility to take measures to reduce vaccination pain; however, there are a plethora of pain relieving interventions during immunizations and it is unclear which interventions are most cost efficient, timely, and effective. Studies have been conducted to investigate the efficacy of different pain management interventions during vaccinations. This review evaluates various pain relieving interventions and provide health care providers age appropriate guidance on pain relieving interventions during vaccinations. Employment of these strategies may successfully reduce vaccination-associated pain in infants, children, and adolescents, and may improve compliance with the vaccination schedule. Keywords: immunization, intervention, effective, compliance

  10. Intranasal P particle vaccine provided partial cross-variant protection against human GII.4 norovirus diarrhea in gnotobiotic pigs.

    Science.gov (United States)

    Kocher, Jacob; Bui, Tammy; Giri-Rachman, Ernawati; Wen, Ke; Li, Guohua; Yang, Xingdong; Liu, Fangning; Tan, Ming; Xia, Ming; Zhong, Weiming; Jiang, Xi; Yuan, Lijuan

    2014-09-01

    Noroviruses (NoVs) are the leading cause of nonbacterial acute gastroenteritis worldwide in people of all ages. The P particle is a novel vaccine candidate derived from the protruding (P) domain of the NoV VP1 capsid protein. This study utilized the neonatal gnotobiotic pig model to evaluate the protective efficacies of primary infection, P particles, and virus-like particles (VLPs) against NoV infection and disease and the T cell responses to these treatments. Pigs either were vaccinated intranasally with GII.4/1997 NoV (VA387)-derived P particles or VLPs or were inoculated orally with a GII.4/2006b NoV variant. At postinoculation day (PID) 28, pigs either were euthanized or were challenged with the GII.4/2006b variant and monitored for diarrhea and virus shedding for 7 days. The T cell responses in intestinal and systemic lymphoid tissues were examined. Primary NoV infection provided 83% homologous protection against diarrhea and 49% homologous protection against virus shedding, while the P particle and VLP vaccines provided cross-variant protection (47% and 60%, respectively) against diarrhea. The protection rates against diarrhea are significantly inversely correlated with T cell expansion in the duodenum and are positively correlated with T cell expansion in the ileum and spleen. The P particle vaccine primed for stronger immune responses than VLPs, including significantly higher numbers of activated CD4+ T cells in all tissues, gamma interferon-producing (IFN-γ+) CD8+ T cells in the duodenum, regulatory T cells (Tregs) in the blood, and transforming growth factor β (TGF-β)-producing CD4+ CD25- FoxP3+ Tregs in the spleen postchallenge, indicating that P particles are more immunogenic than VLPs at the same dose. In conclusion, the P particle vaccine is a promising vaccine candidate worthy of further development. The norovirus (NoV) P particle is a vaccine candidate derived from the protruding (P) domain of the NoV VP1 capsid protein. P particles can be

  11. HA03 as an Iranian Candidate Concealed Antigen for Vaccination against Hyalomma anatolicum anatolicum: Comparative Structural and In silico Studies

    Directory of Open Access Journals (Sweden)

    Mohammadi, A.

    2013-12-01

    Full Text Available In the last decades researchers had focused on developing a vaccine against tick based on protective antigen. Recombinant vaccines based on concealed antigen from Boophilus microplus have been developed in Australia and Cuba by the name of TICKGARD and GAVAC (De La Fuente and Kocan, 2006. Further studies on this antigen have shown some extent of protection against other species (De Vos et al., 2001. In Iran most important species is Hyalomma anatolicum and limited information about its control are available. This paper reports structural and polymorphic analysis of HA03 as an Iranian candidate concealed antigen of H. a. anatolicum deposited in Gen-Bank .(Aghaeipour et al. GQ228820. The comparison between this antigen and other mid gut concealed antigen that their characteristics are available in GenBank showed there are high rate of similarity between them. The HA03 amino acid sequence had a homology of around 89%, 64%, 56% with HA98, BM86, BM95 respectively. Potential of MHC class I and II binding region indicated a considerable variation between BM86 antigen and its efficiency against Iranian H. a. anatolicum. In addition, predicted major of hydrophobisity and similarity in N-glycosylation besides large amount of cystein and seven EGF like regions presented in protein structure revealed that value of HA03 as a new protective antigen and the necessity of the development, BM86 homolog of H. a. anatolicum HA03 based recombinant vaccine.

  12. Status of vaccine research and development of vaccines for herpes simplex virus.

    Science.gov (United States)

    Johnston, Christine; Gottlieb, Sami L; Wald, Anna

    2016-06-03

    Herpes simplex virus type-1 (HSV-1) and -2 (HSV-2) are highly prevalent global pathogens which commonly cause recurrent oral and genital ulcerations. Less common but more serious complications include meningitis, encephalitis, neonatal infection, and keratitis. HSV-2 infection is a significant driver of the HIV epidemic, increasing the risk of HIV acquisition 3 fold. As current control strategies for genital HSV-2 infection, including antiviral therapy and condom use, are only partially effective, vaccines will be required to reduce infection. Both preventive and therapeutic vaccines for HSV-2 are being pursued and are in various stages of development. We will provide an overview of efforts to develop HSV-2 vaccines, including a discussion of the clinical need for an HSV vaccine, and status of research and development with an emphasis on recent insights from trials of vaccine candidates in clinical testing. In addition, we will touch upon aspects of HSV vaccine development relevant to low and middle income countries. Copyright © 2016 World Health Organization. Published by Elsevier Ltd.. All rights reserved.

  13. Immunogenicity, protective efficacy, and non-replicative status of the HSV-2 vaccine candidate HSV529 in mice and guinea pigs.

    Science.gov (United States)

    Bernard, Marie-Clotilde; Barban, Véronique; Pradezynski, Fabrine; de Montfort, Aymeric; Ryall, Robert; Caillet, Catherine; Londono-Hayes, Patricia

    2015-01-01

    HSV-2 vaccine is needed to prevent genital disease, latent infection, and virus transmission. A replication-deficient mutant virus (dl5-29) has demonstrated promising efficacy in animal models of genital herpes. However, the immunogenicity, protective efficacy, and non-replicative status of the highly purified clinical vaccine candidate (HSV529) derived from dl5-29 have not been evaluated. Humoral and cellular immune responses were measured in mice and guinea pigs immunized with HSV529. Protection against acute and recurrent genital herpes, mortality, latent infection, and viral shedding after vaginal HSV-2 infection was determined in mice or in naïve and HSV-1 seropositive guinea pigs. HSV529 replication and pathogenicity were investigated in three sensitive models of virus replication: severe combined immunodeficient (SCID/Beige) mice inoculated by the intramuscular route, suckling mice inoculated by the intracranial route, and vaginally-inoculated guinea pigs. HSV529 immunization induced HSV-2-neutralizing antibody production in mice and guinea pigs. In mice, it induced production of specific HSV-2 antibodies and splenocytes secreting IFNγ or IL-5. Immunization effectively prevented HSV-2 infection in all three animal models by reducing mortality, acute genital disease severity and frequency, and viral shedding. It also reduced ganglionic viral latency and recurrent disease in naïve and HSV-1 seropositive guinea pigs. HSV529 replication/propagation was not detected in the muscles of SCID/Beige mice, in the brains of suckling mice, or in vaginal secretions of inoculated guinea pigs. These results confirm the non-replicative status, as well as its immunogenicity and efficacy in mice and guinea pigs, including HSV-1 seropositive guinea pigs. In mice, HSV529 produced Th1/Th2 characteristic immune response thought to be necessary for an effective vaccine. These results further support the clinical investigation of HSV529 in human subjects as a prophylactic vaccine.

  14. Immunogenicity, protective efficacy, and non-replicative status of the HSV-2 vaccine candidate HSV529 in mice and guinea pigs.

    Directory of Open Access Journals (Sweden)

    Marie-Clotilde Bernard

    Full Text Available HSV-2 vaccine is needed to prevent genital disease, latent infection, and virus transmission. A replication-deficient mutant virus (dl5-29 has demonstrated promising efficacy in animal models of genital herpes. However, the immunogenicity, protective efficacy, and non-replicative status of the highly purified clinical vaccine candidate (HSV529 derived from dl5-29 have not been evaluated. Humoral and cellular immune responses were measured in mice and guinea pigs immunized with HSV529. Protection against acute and recurrent genital herpes, mortality, latent infection, and viral shedding after vaginal HSV-2 infection was determined in mice or in naïve and HSV-1 seropositive guinea pigs. HSV529 replication and pathogenicity were investigated in three sensitive models of virus replication: severe combined immunodeficient (SCID/Beige mice inoculated by the intramuscular route, suckling mice inoculated by the intracranial route, and vaginally-inoculated guinea pigs. HSV529 immunization induced HSV-2-neutralizing antibody production in mice and guinea pigs. In mice, it induced production of specific HSV-2 antibodies and splenocytes secreting IFNγ or IL-5. Immunization effectively prevented HSV-2 infection in all three animal models by reducing mortality, acute genital disease severity and frequency, and viral shedding. It also reduced ganglionic viral latency and recurrent disease in naïve and HSV-1 seropositive guinea pigs. HSV529 replication/propagation was not detected in the muscles of SCID/Beige mice, in the brains of suckling mice, or in vaginal secretions of inoculated guinea pigs. These results confirm the non-replicative status, as well as its immunogenicity and efficacy in mice and guinea pigs, including HSV-1 seropositive guinea pigs. In mice, HSV529 produced Th1/Th2 characteristic immune response thought to be necessary for an effective vaccine. These results further support the clinical investigation of HSV529 in human subjects as a

  15. Development and trial of vaccines against Brucella.

    Science.gov (United States)

    Lalsiamthara, Jonathan; Lee, John Hwa

    2017-08-31

    The search for ideal brucellosis vaccines remains active today. Currently, no licensed human or canine anti-brucellosis vaccines are available. In bovines, the most successful vaccine (S19) is only used in calves, as adult vaccination results in orchitis in male, prolonged infection, and possible abortion complications in pregnant female cattle. Another widely deployed vaccine (RB51) has a low protective efficacy. An ideal vaccine should exhibit a safe profile as well as enhance protective efficacy. However, currently available vaccines exhibit one or more major drawbacks. Smooth live attenuated vaccines suffer shortcomings such as residual virulence and serodiagnostic interference. Inactivated vaccines, in general, confer relatively low levels of protection. Recent developments to improve brucellosis vaccines include generation of knockout mutants by targeting genes involved in metabolism, virulence, and the lipopolysaccharide synthesis pathway, as well as generation of DNA vaccines, mucosal vaccines, and live vectored vaccines, have all produced varying degrees of success. Herein, we briefly review the bacteriology, pathogenesis, immunological implications, candidate vaccines, vaccinations, and models related to Brucella .

  16. Temperature-sensitive mutations for live-attenuated Rift Valley fever vaccines: Implications from other RNA viruses

    Directory of Open Access Journals (Sweden)

    Shoko eNishiyama

    2015-08-01

    Full Text Available Rift Valley fever (RVF is a mosquito-borne zoonotic disease endemic to the African continent. RVF is characterized by high rate of abortions in ruminants and hemorrhagic fever, encephalitis or blindness in humans. RVF is caused by the Rift Valley fever virus (RVFV: genus Phlebovirus, family Bunyaviridae. Vaccination is the only known effective strategy to prevent the disease, but there are no licensed RVF vaccines available for humans. A live-attenuated vaccine candidate derived from the wild-type pathogenic Egyptian ZH548 strain, MP-12, has been conditionally licensed for veterinary use in the United States. MP-12 displays a temperature-sensitive (ts phenotype and does not replicate at 41oC. The ts mutation limits viral replication at a specific body temperature and may lead to an attenuation of the virus. Here we will review well-characterized ts mutations for RNA viruses, and further discuss the potential in designing novel live-attenuated vaccines for RVF.

  17. Antigen-Specific lgA B Memory Cell Responses to Shigella Antigens Elicited in Volunteers Immunized with Live Attenuated Shigella flexneri 2a Oral Vaccine Candidates

    Science.gov (United States)

    2011-01-01

    167. [10] E.V. Oaks, T.L. Hale, S.B. Formal, Serum immune response to Shigella protein antigens in rhesus monkeys and humans infected with Shigella ...cell responses to Shigella antigens elicited in volunteers immunized with live attenuated Shigella flexneri 2a oral vaccine candidates J.K. Simona,b... Shigella ;. B cell memory; Immunoglobulin lgA; Mucosal immunity Abstract We studied the induction of antigen-specific lgA memory B cells (BM) in

  18. A cell wall protein-based vaccine candidate induce protective immune response against Sporothrix schenckii infection.

    Science.gov (United States)

    Portuondo, Deivys Leandro; Batista-Duharte, Alexander; Ferreira, Lucas Souza; Martínez, Damiana Téllez; Polesi, Marisa Campos; Duarte, Roberta Aparecida; de Paula E Silva, Ana Carolina Alves; Marcos, Caroline Maria; Almeida, Ana Marisa Fusco de; Carlos, Iracilda Zeppone

    2016-02-01

    Sporotrichosis is a subcutaneous mycosis caused by several closely related thermo-dimorphic fungi of the Sporothrix schenckii species complex, affecting humans and other mammals. In the last few years, new strategies have been proposed for controlling sporotrichosis owning to concerns about its growing incidence in humans, cats, and dogs in Brazil, as well as the toxicity and limited efficacy of conventional antifungal drugs. In this study, we assessed the immunogenicity and protective properties of two aluminum hydroxide (AH)-adsorbed S. schenckii cell wall protein (ssCWP)-based vaccine formulations in a mouse model of systemic S. schenckii infection. Fractioning by SDS-PAGE revealed nine protein bands, two of which were functionally characterized: a 44kDa peptide hydrolase and a 47kDa enolase, which was predicted to be an adhesin. Sera from immunized mice recognized the 47kDa enolase and another unidentified 71kDa protein, whereas serum from S. schenckii-infected mice recognized both these proteins plus another unidentified 9.4kDa protein. Furthermore, opsonization with the anti-ssCWP sera led to markedly increased phagocytosis and was able to strongly inhibit the fungus' adhesion to fibroblasts. Immunization with the higher-dose AH-adjuvanted formulation led to increased ex vivo release of IL-12, IFN-γ, IL-4, and IL-17, whereas only IL-12 and IFN-γ were induced by the higher-dose non-adjuvanted formulation. Lastly, passive transference of the higher-dose AH-adjuvanted formulation's anti-ssCWP serum was able to afford in vivo protection in a subsequent challenge with S. schenckii, becoming a viable vaccine candidate for further testing. Copyright © 2015 Elsevier GmbH. All rights reserved.

  19. Vaccines for viral and bacterial pathogens causing acute gastroenteritis: Part II: Vaccines for Shigella, Salmonella, enterotoxigenic E. coli (ETEC) enterohemorragic E. coli (EHEC) and Campylobacter jejuni

    Science.gov (United States)

    O’Ryan, Miguel; Vidal, Roberto; del Canto, Felipe; Carlos Salazar, Juan; Montero, David

    2015-01-01

    In Part II we discuss the following bacterial pathogens: Shigella, Salmonella (non-typhoidal), diarrheogenic E. coli (enterotoxigenic and enterohemorragic) and Campylobacter jejuni. In contrast to the enteric viruses and Vibrio cholerae discussed in Part I of this series, for the bacterial pathogens described here there is only one licensed vaccine, developed primarily for Vibrio cholerae and which provides moderate protection against enterotoxigenic E. coli (ETEC) (Dukoral®), as well as a few additional candidates in advanced stages of development for ETEC and one candidate for Shigella spp. Numerous vaccine candidates in earlier stages of development are discussed. PMID:25715096

  20. Single-dose mucosal immunization with a candidate universal influenza vaccine provides rapid protection from virulent H5N1, H3N2 and H1N1 viruses.

    Directory of Open Access Journals (Sweden)

    Graeme E Price

    2010-10-01

    Full Text Available The sudden emergence of novel influenza viruses is a global public health concern. Conventional influenza vaccines targeting the highly variable surface glycoproteins hemagglutinin and neuraminidase must antigenically match the emerging strain to be effective. In contrast, "universal" vaccines targeting conserved viral components could be used regardless of viral strain or subtype. Previous approaches to universal vaccination have required protracted multi-dose immunizations. Here we evaluate a single dose universal vaccine strategy using recombinant adenoviruses (rAd expressing the conserved influenza virus antigens matrix 2 and nucleoprotein.In BALB/c mice, administration of rAd via the intranasal route was superior to intramuscular immunization for induction of mucosal responses and for protection against highly virulent H1N1, H3N2, or H5N1 influenza virus challenge. Mucosally vaccinated mice not only survived, but had little morbidity and reduced lung virus titers. Protection was observed as early as 2 weeks post-immunization, and lasted at least 10 months, as did antibodies and lung T cells with activated phenotypes. Virus-specific IgA correlated with but was not essential for protection, as demonstrated in studies with IgA-deficient animals.Mucosal administration of NP and M2-expressing rAd vectors provided rapid and lasting protection from influenza viruses in a subtype-independent manner. Such vaccines could be used in the interval between emergence of a new virus strain and availability of strain-matched vaccines against it. This strikingly effective single-dose vaccination thus represents a candidate off-the-shelf vaccine for emergency use during an influenza pandemic.

  1. Vaccination against tuberculosis.

    Science.gov (United States)

    Martin, Carlos; Aguilo, Nacho; Gonzalo-Asensio, Jesús

    2018-04-04

    BCG (Bacille Calmette-Guérin) vaccination is included in the immunization schedule for tuberculosis endemic countries with a global coverage at birth close to 90% worldwide. BCG was attenuated from Mycobacterium bovis almost a century ago, and provides a strong protection against disseminated forms of the disease, though very limited against pulmonary forms of tuberculosis, responsible for transmission. Novel prophylactic tuberculosis vaccines are in clinical development either to replace BCG or to improve its protection against respiratory forms of the disease. There are limitations understanding the immunological responses involved and the precise type of long-lived immunity that new vaccines need to induce. MTBVAC is the first and only tuberculosis vaccine candidate based on live-attenuated Mycobacterium tuberculosis in clinical evaluation. MTBVAC clinical development plans to target tuberculosis prevention in newborns, as a BCG replacement strategy, and as secondary objective to be tested in adolescents and adults previous vaccinated with BCG. Copyright © 2018 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  2. Ebola hemorrhagic Fever and the current state of vaccine development.

    Science.gov (United States)

    Hong, Joo Eun; Hong, Kee-Jong; Choi, Woo Young; Lee, Won-Ja; Choi, Yeon Hwa; Jeong, Chung-Hyeon; Cho, Kwang-Il

    2014-12-01

    Current Ebola virus outbreak in West Africa already reached the total number of 1,323 including 729 deaths by July 31st. the fatality is around 55% in the southeastern area of Guinea, Sierra Leone, Liberia, and Nigeria. The number of patients with Ebola Hemorrhagic Fever (EHF) was continuously increasing even though the any effective therapeutics or vaccines has not been developed yet. The Ebola virus in Guinea showed 98% homology with Zaire Ebola Virus. Study of the pathogenesis of Ebola virus infection and assess of the various candidates of vaccine have been tried for a long time, especially in United States and some European countries. Even though the attenuated live vaccine and DNA vaccine containing Ebola viral genes were tested and showed efficacy in chimpanzees, those candidates still need clinical tests requiring much longer time than the preclinical development to be approved for the practical treatment. It can be expected to eradicate Ebola virus by a safe and efficient vaccine development similar to the case of smallpox virus which was extinguished from the world by the variola vaccine.

  3. Economic value of dengue vaccine in Thailand.

    Science.gov (United States)

    Lee, Bruce Y; Connor, Diana L; Kitchen, Sarah B; Bacon, Kristina M; Shah, Mirat; Brown, Shawn T; Bailey, Rachel R; Laosiritaworn, Yongjua; Burke, Donald S; Cummings, Derek A T

    2011-05-01

    With several candidate dengue vaccines under development, this is an important time to help stakeholders (e.g., policy makers, scientists, clinicians, and manufacturers) better understand the potential economic value (cost-effectiveness) of a dengue vaccine, especially while vaccine characteristics and strategies might be readily altered. We developed a decision analytic Markov simulation model to evaluate the potential health and economic value of administering a dengue vaccine to an individual (≤ 1 year of age) in Thailand from the societal perspective. Sensitivity analyses evaluated the effects of ranging various vaccine (e.g., cost, efficacy, side effect), epidemiological (dengue risk), and disease (treatment-seeking behavior) characteristics. A ≥ 50% efficacious vaccine was highly cost-effective [GDP) ($4,289)] up to a total vaccination cost of $60 and cost-effective [GDP ($12,868)] up to a total vaccination cost of $200. When the total vaccine series was $1.50, many scenarios were cost saving.

  4. Molecular characterization of thyroid hormone receptor beta from Schistosoma japonicum and assessment of its potential as a vaccine candidate antigen against schistosomiasis in BALB/c mice

    Directory of Open Access Journals (Sweden)

    Qiu Chunhui

    2012-08-01

    Full Text Available Abstract Background Thyroid hormones (TH modulate growth, development and differentiation and metabolic processes by interacting with thyroid hormone receptors (THRs. The purpose of this study was to identify a novel thyroid hormone receptor beta encoding gene of Schistosoma japonicum (SjTHRβ and to investigate its potential as a vaccine candidate antigen against schistosomiasis in BALB/c mice. Methods The full-length cDNA sequence of SjTHRβ, its gene organization, and its transcript levels were characterized, and the phylogenetic relationship between THR, RAR and RXR from other organisms were analysis, the ability of this protein binding to a conserved DNA core motif, and its potential as a vaccine candidate antigen against schistosomiasis in BALB/c mice were evaluated. Results The SjTHRβ cDNA was cloned, verified by 5’ and 3’ Rapid Amplification of cDNA Ends and shown to be polyadenylated at the 3’end, suggesting the transcript is full-length. SjTHRβ is homologous to THRs from other species and has a predicted conservative DNA binding domain and ligand binding domain that normally characterizes these receptors. A comparative quantitative PCR analysis showed that SjTHRβ was the highest expressed in 21d worms and the lowest in 7 d and 13 d schistosomula. The cDNA corresponding to DNA binding domain (SjTHRβ-DBD and ligand binding domain (SjTHRβ-LBD were cloned and subsequently expressed in E coli. The expressed proteins were used to immunize mice and generate specific serum against recombinant SjTHRβ (rSjTHRβ. Western blotting revealed that anti-rSjTHRβ-LBD serum recognized two protein bands in extracts from 21 d worm with molecular sizes of approximately 95 kDa and 72 kDa. Electrophoretic mobility shift assay (EMSA analysis showed that rSjTHRβ-DBD could bind to a conserved DNA core motif. Immunization of BALB/c mice with rSjTHRβ-LBD could induce partial protective efficacy(27.52% worm reduction and 29.50% liver eggs

  5. Subunit vaccine candidates against Aeromonas salmonicida in rainbow trout Oncorhynchus mykiss

    DEFF Research Database (Denmark)

    Marana, Moonika Haahr; Jørgensen, Louise von Gersdorff; Skov, Jakob

    2017-01-01

    rainbow trout (Oncorhynchus mykiss, Walbaum) aquaculture furunculosis outbreaks still occur. In this study we tested the efficacy of experimental subunit vaccines against A. salmonicida infection in rainbow trout. We utilized in silico screening of the proteome of A. salmonicida subsp. salmonicida strain...... A449 and identified potential protective protein antigens that were tested by in vivo challenge trial. A total of 14 proteins were recombinantly expressed in Escherichia coli and prepared in 3 different subunit vaccine combinations to immunize 3 groups of rainbow trout by intraperitoneal (i...

  6. Bioinformatics in New Generation Flavivirus Vaccines

    Directory of Open Access Journals (Sweden)

    Penelope Koraka

    2010-01-01

    Full Text Available Flavivirus infections are the most prevalent arthropod-borne infections world wide, often causing severe disease especially among children, the elderly, and the immunocompromised. In the absence of effective antiviral treatment, prevention through vaccination would greatly reduce morbidity and mortality associated with flavivirus infections. Despite the success of the empirically developed vaccines against yellow fever virus, Japanese encephalitis virus and tick-borne encephalitis virus, there is an increasing need for a more rational design and development of safe and effective vaccines. Several bioinformatic tools are available to support such rational vaccine design. In doing so, several parameters have to be taken into account, such as safety for the target population, overall immunogenicity of the candidate vaccine, and efficacy and longevity of the immune responses triggered. Examples of how bio-informatics is applied to assist in the rational design and improvements of vaccines, particularly flavivirus vaccines, are presented and discussed.

  7. Rational development of an attenuated recombinant cyprinid herpesvirus 3 vaccine using prokaryotic mutagenesis and in vivo bioluminescent imaging.

    Science.gov (United States)

    Boutier, Maxime; Ronsmans, Maygane; Ouyang, Ping; Fournier, Guillaume; Reschner, Anca; Rakus, Krzysztof; Wilkie, Gavin S; Farnir, Frédéric; Bayrou, Calixte; Lieffrig, François; Li, Hong; Desmecht, Daniel; Davison, Andrew J; Vanderplasschen, Alain

    2015-02-01

    Cyprinid herpesvirus 3 (CyHV 3) is causing severe economic losses worldwide in common and koi carp industries, and a safe and efficacious attenuated vaccine compatible with mass vaccination is needed. We produced single deleted recombinants using prokaryotic mutagenesis. When producing a recombinant lacking open reading frame 134 (ORF134), we unexpectedly obtained a clone with additional deletion of ORF56 and ORF57. This triple deleted recombinant replicated efficiently in vitro and expressed an in vivo safety/efficacy profile compatible with use as an attenuated vaccine. To determine the role of the double ORF56-57 deletion in the phenotype and to improve further the quality of the vaccine candidate, a series of deleted recombinants was produced and tested in vivo. These experiments led to the selection of a double deleted recombinant lacking ORF56 and ORF57 as a vaccine candidate. The safety and efficacy of this strain were studied using an in vivo bioluminescent imaging system (IVIS), qPCR, and histopathological examination, which demonstrated that it enters fish via skin infection similar to the wild type strain. However, compared to the parental wild type strain, the vaccine candidate replicated at lower levels and spread less efficiently to secondary sites of infection. Transmission experiments allowing water contamination with or without additional physical contact between fish demonstrated that the vaccine candidate has a reduced ability to spread from vaccinated fish to naïve sentinel cohabitants. Finally, IVIS analyses demonstrated that the vaccine candidate induces a protective mucosal immune response at the portal of entry. Thus, the present study is the first to report the rational development of a recombinant attenuated vaccine against CyHV 3 for mass vaccination of carp. We also demonstrated the relevance of the CyHV 3 carp model for studying alloherpesvirus transmission and mucosal immunity in teleost skin.

  8. ERM immersion vaccination and adjuvants

    DEFF Research Database (Denmark)

    Skov, J.; Chettri, J. K.; Jaafar, R. M.

    2015-01-01

    Two candidate adjuvants were tested with a commercial ERM dip vaccine (AquaVac™ Relera, MSD Animal Health) for rainbow trout in an experimental design compatible with common vaccination practices at farm level, i.e. immersion of fish in vaccine (±adjuvant) for 30 s. The adjuvants were...... the commercial product Montanide™ IMS 1312 VG PR (SEPPIC), and a soluble and ≥98% pure β-glucan from yeast (Saccharomyces cerevisiae) (Sigma-Aldrich). Hence, five experimental groups in duplicate were established and exposed to vaccine and adjuvants in the following combinations: AquaVac™ Relera (alone); Aqua......Vac™ Relera + Montanide™; AquaVac™ Relera + β-glucan; Montanide™ (alone); and β-glucan (alone). Approximately 450 degree days post-vaccination, the fish were bath-challenged with live Yersinia ruckeri to produce survival curves. Blood, skin and gills were sampled at selected time points during the course...

  9. Polymeric micro/nanoparticles: Particle design and potential vaccine delivery applications.

    Science.gov (United States)

    Yue, Hua; Ma, Guanghui

    2015-11-04

    Particle based adjuvant showed promising signs on delivering antigen to immune cells and acting as stimulators to elicit preventive or therapeutic response. Nevertheless, the wide size distribution of available polymeric particles has so far obscured the immunostimulative effects of particle adjuvant, and compromised the progress in pharmacological researches. To conquer this hurdle, our research group has carried out a series of researches regarding the particulate vaccine, by taking advantage of the successful fabrication of polymeric particles with uniform size. In this review, we highlight the insight and practical progress focused on the effects of physiochemical property (e.g. particle size, charge, hydrophobicity, surface chemical group, and particle shape) and antigen loading mode on the resultant biological/immunological outcome. The underlying mechanisms of how the particles-based vaccine functioned in the immune system are also discussed. Based on the knowledge, particles with high antigen payload and optimized attributes could be designed for expected adjuvant purpose, leading to the development of high efficient vaccine candidates. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Characterization of candidate DOE sites for fabricating MOX fuel for lead assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Holdaway, R.F.; Miller, J.W.; Sease, J.D.; Moses, R.J.; O`Connor, D.G. [Oak Ridge National Lab., TN (United States); Carrell, R.D. [Technical Resources International, Inc., Richland, WA (United States); Jaeger, C.D. [Sandia National Labs., Albuquerque, NM (United States); Thompson, M.L.; Strasser, A.A. [Delta-21 Resources, Inc., Oak Ridge, TN (United States)

    1998-03-01

    The Office of Fissile Materials Disposition (MD) of the Department of Energy (DOE) is directing the program to disposition US surplus weapons-usable plutonium. For the reactor option for disposition of this surplus plutonium, MD is seeking to contract with a consortium, which would include a mixed-oxide (MOX) fuel fabricator and a commercial US reactor operator, to fabricate and burn MOX fuel in existing commercial nuclear reactors. This option would entail establishing a MOX fuel fabrication facility under the direction of the consortium on an existing DOE site. Because of the lead time required to establish a MOX fuel fabrication facility and the need to qualify the MOX fuel for use in a commercial reactor, MD is considering the early fabrication of lead assemblies (LAs) in existing DOE facilities under the technical direction of the consortium. The LA facility would be expected to produce a minimum of 1 metric ton heavy metal per year and must be operational by June 2003. DOE operations offices were asked to identify candidate sites and facilities to be evaluated for suitability to fabricate MOX fuel LAs. Savannah River Site, Argonne National Laboratory-West, Hanford, Lawrence Livermore National Laboratory, and Los Alamos National Laboratory were identified as final candidates to host the LA project. A Site Evaluation Team (SET) worked with each site to develop viable plans for the LA project. SET then characterized the suitability of each of the five plans for fabricating MOX LAs using 28 attributes and documented the characterization to aid DOE and the consortium in selecting the site for the LA project. SET concluded that each option has relative advantages and disadvantages in comparison with other options; however, each could meet the requirements of the LA project as outlined by MD and SET.

  11. Characterization of candidate DOE sites for fabricating MOX fuel for lead assemblies

    International Nuclear Information System (INIS)

    Holdaway, R.F.; Miller, J.W.; Sease, J.D.; Moses, R.J.; O'Connor, D.G.; Carrell, R.D.; Jaeger, C.D.; Thompson, M.L.; Strasser, A.A.

    1998-03-01

    The Office of Fissile Materials Disposition (MD) of the Department of Energy (DOE) is directing the program to disposition US surplus weapons-usable plutonium. For the reactor option for disposition of this surplus plutonium, MD is seeking to contract with a consortium, which would include a mixed-oxide (MOX) fuel fabricator and a commercial US reactor operator, to fabricate and burn MOX fuel in existing commercial nuclear reactors. This option would entail establishing a MOX fuel fabrication facility under the direction of the consortium on an existing DOE site. Because of the lead time required to establish a MOX fuel fabrication facility and the need to qualify the MOX fuel for use in a commercial reactor, MD is considering the early fabrication of lead assemblies (LAs) in existing DOE facilities under the technical direction of the consortium. The LA facility would be expected to produce a minimum of 1 metric ton heavy metal per year and must be operational by June 2003. DOE operations offices were asked to identify candidate sites and facilities to be evaluated for suitability to fabricate MOX fuel LAs. Savannah River Site, Argonne National Laboratory-West, Hanford, Lawrence Livermore National Laboratory, and Los Alamos National Laboratory were identified as final candidates to host the LA project. A Site Evaluation Team (SET) worked with each site to develop viable plans for the LA project. SET then characterized the suitability of each of the five plans for fabricating MOX LAs using 28 attributes and documented the characterization to aid DOE and the consortium in selecting the site for the LA project. SET concluded that each option has relative advantages and disadvantages in comparison with other options; however, each could meet the requirements of the LA project as outlined by MD and SET

  12. [New vaccines against group B meningococcal diseases].

    Science.gov (United States)

    Hietalahti, Jukka; Meri, Seppo

    2015-01-01

    There has been no efficient general vaccine against serogroup B meningococcus (MenB), since its polysialic acid capsule is of low immunogenicity and could potentially induce autoimmunity. Reverse vaccinology has revealed new promising protein candidates for vaccine development. One of them is factor H-binding protein (fHbp), which has the potential to curb the alternative pathway of human complement. As fHbp can elicit antibodies that promote complement-mediated lysis, a vaccine partly based on it has been introduced against MenB infections. FHbp has been the milestone protein for structural vaccinology to create optimal chimeric antigens for vaccine use.

  13. Preventive medicines: vaccination, prophylaxis of infectious diseases, disinfectants.

    Science.gov (United States)

    Heininger, Ulrich

    2011-01-01

    Immunizations belong to the most successful interventions in medicine. Like other drugs, vaccines undergo long periods of pre-clinical development, followed by careful clinical testing through study Phases I, II, and III before they receive licensure. A successful candidate vaccine will move on to be an investigational vaccine to undergo three phases of pre-licensure clinical trials in a stepwise fashion before it can be considered for approval, followed by an optional fourth phase of post-marketing assessment. The overall risk-benefit assessment of a candidate vaccine is very critical in making the licensure decision for regulatory authorities, supported by their scientific committees. It includes analyses of immunogenicity, efficacy, reactogenicity or tolerability, and safety of the vaccine. Public trust in vaccines is a key to the success of immunization programs worldwide. Maintaining this trust requires knowledge of the benefits and scientific understanding of real or perceived risks of immunizations. Under certain circumstances, pre- or post-exposure passive immunization can be achieved by administration of immunoglobulines. In terms of prevention of infectious diseases, disinfection can be applied to reduce the risk of transmission of pathogens from patient to patient, health-care workers to patients, patients to health-care workers, and objects or medical devices to patients.

  14. Intranasal delivery of a protein subunit vaccine using a Tobacco Mosaic Virus platform protects against pneumonic plague.

    Science.gov (United States)

    Arnaboldi, Paul M; Sambir, Mariya; D'Arco, Christina; Peters, Lauren A; Seegers, Jos F M L; Mayer, Lloyd; McCormick, Alison A; Dattwyler, Raymond J

    2016-11-11

    Yersinia pestis, one of history's deadliest pathogens, has killed millions over the course of human history. It has attributes that make it an ideal choice to produce mass casualties and is a prime candidate for use as a biological weapon. When aerosolized, Y. pestis causes pneumonic plague, a pneumonia that is 100% lethal if not promptly treated with effective antibiotics. Currently, there is no FDA approved plague vaccine. The current lead vaccine candidate, a parenterally administered protein subunit vaccine comprised of the Y. pestis virulence factors, F1 and LcrV, demonstrated variable levels of protection in primate pneumonic plague models. As the most likely mode of exposure in biological attack with Y. pestis is by aerosol, this raises a question of whether this parenteral vaccine will adequately protect humans against pneumonic plague. In the present study we evaluated two distinct mucosal delivery platforms for the intranasal (IN) administration of LcrV and F1 vaccine proteins, a live bacterial vector, Lactobacillus plantarum, and a Tobacco Mosaic Virus (TMV) based delivery platform. IN administration of L. plantarum expressing LcrV, or TMV-conjugated to LcrV and F1 (TMV-LcrV+TMV-F1) resulted in the similar induction of high titers of IgG antibodies and evidence of proinflammatory cytokine secretion. However, only the TMV-conjugate delivery platform protected against subsequent lethal challenge with Y. pestis. TMV-LcrV+TMV-F1 co-vaccinated mice had no discernable morbidity and no mortality, while mice vaccinated with L. plantarum expressing LcrV or rLcrV+rF1 without TMV succumbed to infection or were only partially protected. Thus, TMV is a suitable mucosal delivery platform for an F1-LcrV subunit vaccine that induces complete protection against pneumonic infection with a lethal dose of Y. pestis in mice. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Phase I safety and immunogenicity evaluation of MVA-CMDR, a multigenic, recombinant modified vaccinia Ankara-HIV-1 vaccine candidate.

    Science.gov (United States)

    Currier, Jeffrey R; Ngauy, Viseth; de Souza, Mark S; Ratto-Kim, Silvia; Cox, Josephine H; Polonis, Victoria R; Earl, Patricia; Moss, Bernard; Peel, Sheila; Slike, Bonnie; Sriplienchan, Somchai; Thongcharoen, Prasert; Paris, Robert M; Robb, Merlin L; Kim, Jerome; Michael, Nelson L; Marovich, Mary A

    2010-11-15

    We conducted a Phase I randomized, dose-escalation, route-comparison trial of MVA-CMDR, a candidate HIV-1 vaccine based on a recombinant modified vaccinia Ankara viral vector expressing HIV-1 genes env/gag/pol. The HIV sequences were derived from circulating recombinant form CRF01_AE, which predominates in Thailand. The objective was to evaluate safety and immunogenicity of MVA-CMDR in human volunteers in the US and Thailand. MVA-CMDR or placebo was administered intra-muscularly (IM; 10(7) or 10(8) pfu) or intradermally (ID; 10(6) or 10(7) pfu) at months 0, 1 and 3, to 48 healthy volunteers at low risk for HIV-1 infection. Twelve volunteers in each dosage group were randomized to receive MVA-CMDR or placebo (10∶2). Volunteers were actively monitored for local and systemic reactogenicity and adverse events post vaccination. Cellular immunogenicity was assessed by a validated IFNγ Elispot assay, an intracellular cytokine staining assay, lymphocyte proliferation and a (51)Cr-release assay. Humoral immunogenicity was assessed by ADCC for gp120 and binding antibody ELISAs for gp120 and p24. MVA-CMDR was safe and well tolerated with no vaccine related serious adverse events. Cell-mediated immune responses were: (i) moderate in magnitude (median IFNγ Elispot of 78 SFC/10(6) PBMC at 10(8) pfu IM), but high in response rate (70% (51)Cr-release positive; 90% Elispot positive; 100% ICS positive, at 10(8) pfu IM); (ii) predominantly HIV Env-specific CD4(+) T cells, with a high proliferative capacity and durable for at least 6 months (100% LPA response rate by the IM route); (iv) dose- and route-dependent with 10(8) pfu IM being the most immunogenic treatment. Binding antibodies against gp120 and p24 were detectable in all vaccination groups with ADCC capacity detectable at the highest dose (40% positive at 10(8) pfu IM). MVA-CMDR delivered both intramuscularly and intradermally was safe, well-tolerated and elicited durable cell-mediated and humoral immune responses

  16. Phase I safety and immunogenicity evaluation of MVA-CMDR, a multigenic, recombinant modified vaccinia Ankara-HIV-1 vaccine candidate.

    Directory of Open Access Journals (Sweden)

    Jeffrey R Currier

    2010-11-01

    Full Text Available We conducted a Phase I randomized, dose-escalation, route-comparison trial of MVA-CMDR, a candidate HIV-1 vaccine based on a recombinant modified vaccinia Ankara viral vector expressing HIV-1 genes env/gag/pol. The HIV sequences were derived from circulating recombinant form CRF01_AE, which predominates in Thailand. The objective was to evaluate safety and immunogenicity of MVA-CMDR in human volunteers in the US and Thailand.MVA-CMDR or placebo was administered intra-muscularly (IM; 10(7 or 10(8 pfu or intradermally (ID; 10(6 or 10(7 pfu at months 0, 1 and 3, to 48 healthy volunteers at low risk for HIV-1 infection. Twelve volunteers in each dosage group were randomized to receive MVA-CMDR or placebo (10∶2. Volunteers were actively monitored for local and systemic reactogenicity and adverse events post vaccination. Cellular immunogenicity was assessed by a validated IFNγ Elispot assay, an intracellular cytokine staining assay, lymphocyte proliferation and a (51Cr-release assay. Humoral immunogenicity was assessed by ADCC for gp120 and binding antibody ELISAs for gp120 and p24. MVA-CMDR was safe and well tolerated with no vaccine related serious adverse events. Cell-mediated immune responses were: (i moderate in magnitude (median IFNγ Elispot of 78 SFC/10(6 PBMC at 10(8 pfu IM, but high in response rate (70% (51Cr-release positive; 90% Elispot positive; 100% ICS positive, at 10(8 pfu IM; (ii predominantly HIV Env-specific CD4(+ T cells, with a high proliferative capacity and durable for at least 6 months (100% LPA response rate by the IM route; (iv dose- and route-dependent with 10(8 pfu IM being the most immunogenic treatment. Binding antibodies against gp120 and p24 were detectable in all vaccination groups with ADCC capacity detectable at the highest dose (40% positive at 10(8 pfu IM.MVA-CMDR delivered both intramuscularly and intradermally was safe, well-tolerated and elicited durable cell-mediated and humoral immune responses

  17. Establishing Correlates of Protection for Vaccine Development: Considerations for the Respiratory Syncytial Virus Vaccine Field.

    Science.gov (United States)

    Kulkarni, Prasad S; Hurwitz, Julia L; Simões, Eric A F; Piedra, Pedro A

    2018-03-01

    Correlates of protection (CoPs) can play a significant role in vaccine development by assisting the selection of vaccine candidates for clinical trials, supporting clinical trial design and implementation, and simplifying tests of vaccine modifications. Because of this important role in vaccine development, it is essential that CoPs be defined by well-designed immunogenicity and efficacy studies, with attention paid to benefits and limitations. The respiratory syncytial virus (RSV) field is unique in that a great deal of information about the humoral response is available from basic research and clinical studies. Polyclonal and monoclonal antibodies have been used routinely in the clinic to protect vulnerable infants from infection, providing a wealth of information about correlations between neutralizing antibodies and disease prevention. Considerations for the establishment of future CoPs to support RSV vaccine development in different populations are therefore discussed.

  18. Rotavirus vaccines

    Science.gov (United States)

    Yen, Catherine; Tate, Jacqueline E; Hyde, Terri B; Cortese, Margaret M; Lopman, Benjamin A; Jiang, Baoming; Glass, Roger I; Parashar, Umesh D

    2014-01-01

    Rotavirus is the leading cause of severe diarrhea among children rotavirus vaccines have been efficacious and effective, with many countries reporting substantial declines in diarrheal and rotavirus-specific morbidity and mortality. However, the full public health impact of these vaccines has not been realized. Most countries, including those with the highest disease burden, have not yet introduced rotavirus vaccines into their national immunization programs. Research activities that may help inform vaccine introduction decisions include (1) establishing effectiveness, impact, and safety for rotavirus vaccines in low-income settings; (2) identifying potential strategies to improve performance of oral rotavirus vaccines in developing countries, such as zinc supplementation; and (3) pursuing alternate approaches to oral vaccines, such as parenteral immunization. Policy- and program-level barriers, such as financial implications of new vaccine introductions, should be addressed to ensure that countries are able to make informed decisions regarding rotavirus vaccine introduction. PMID:24755452

  19. Rotavirus Vaccine

    Science.gov (United States)

    Why get vaccinated?Rotavirus is a virus that causes diarrhea, mostly in babies and young children. The diarrhea can be severe, and lead ... and fever are also common in babies with rotavirus.Before rotavirus vaccine, rotavirus disease was a common ...

  20. Humoral immune response to Plasmodium falciparum vaccine candidate GMZ2 and its components in populations naturally exposed to seasonal malaria in Ethiopia

    DEFF Research Database (Denmark)

    Mamo, Hassen; Esen, Meral; Ajua, Anthony

    2013-01-01

    for malaria infection microscopically and by the rapid diagnostic test (RDT). Sera were tested by using enzyme-linked immunosorbent assay (ELISA) for total immunoglobulin (Ig) G against P. falciparum blood-stage vaccine candidate GMZ2 and its subunits (Glutamate-rich protein (GLURP-R0), merozoite surface...... transmission in the two localities and/or genetic differences between the two populations in their response to the antigens. In both study sites, IgG subclass levels to GLURP-R0 were significantly higher than that to MSP3 for all corresponding subclasses in most individuals, indicating the higher relative...

  1. Influenza vaccination guidelines and vaccine sales in southeast Asia: 2008-2011.

    Directory of Open Access Journals (Sweden)

    Vinay Gupta

    Full Text Available BACKGROUND: Southeast Asia is a region with great potential for the emergence of a pandemic influenza virus. Global efforts to improve influenza surveillance in this region have documented the burden and seasonality of influenza viruses and have informed influenza prevention strategies, but little information exists about influenza vaccination guidelines and vaccine sales. METHODS: To ascertain the existence of influenza vaccine guidelines and define the scope of vaccine sales, we sent a standard three-page questionnaire to the ten member nations of the Association of Southeast Asian Nations. We also surveyed three multinational manufacturers who supply influenza vaccines in the region. RESULTS: Vaccine sales in the private sector were <1000 per 100,000 population in the 10 countries. Five countries reported purchasing vaccine for use in the public sector. In 2011, Thailand had the highest combined reported rate of vaccine sales (10,333 per 100,000. In the 10 countries combined, the rate of private sector sales during 2010-2011 (after the A(H1N12009pdm pandemic exceeded 2008 pre-pandemic levels. Five countries (Indonesia, Malaysia, Singapore, Thailand and Vietnam had guidelines for influenza vaccination but only two were consistent with global guidelines. Four recommended vaccination for health care workers, four for elderly persons, three for young children, three for persons with underlying disease, and two for pregnant women. CONCLUSIONS: The rate of vaccine sales in Southeast Asia remains low, but there was a positive impact in sales after the A(H1N12009pdm pandemic. Low adherence to global vaccine guidelines suggests that more work is needed in the policy arena.

  2. An E2-Substituted Chimeric Pestivirus With DIVA Vaccine Properties

    DEFF Research Database (Denmark)

    Rasmussen, Thomas Bruun; Uttenthal, Åse; Nielsen, Jens

    An advantage of the use of chimeric pestiviruses as modified live vaccines against classical swine fever (CSF) resides in their capacity to be manipulated to achieve the characteristics desired for safe and efficacious DIVA vaccines. We have recently generated a new chimeric virus, Riems26_E2gif...... vaccinated pigs were protected. This new chimeric pestivirus represents a C-strain based DIVA vaccine candidate that can be differentiated based on CSFV E2 specific antibodies....

  3. A Recombinant Vesicular Stomatitis Virus Ebola Vaccine.

    Science.gov (United States)

    Regules, Jason A; Beigel, John H; Paolino, Kristopher M; Voell, Jocelyn; Castellano, Amy R; Hu, Zonghui; Muñoz, Paula; Moon, James E; Ruck, Richard C; Bennett, Jason W; Twomey, Patrick S; Gutiérrez, Ramiro L; Remich, Shon A; Hack, Holly R; Wisniewski, Meagan L; Josleyn, Matthew D; Kwilas, Steven A; Van Deusen, Nicole; Mbaya, Olivier Tshiani; Zhou, Yan; Stanley, Daphne A; Jing, Wang; Smith, Kirsten S; Shi, Meng; Ledgerwood, Julie E; Graham, Barney S; Sullivan, Nancy J; Jagodzinski, Linda L; Peel, Sheila A; Alimonti, Judie B; Hooper, Jay W; Silvera, Peter M; Martin, Brian K; Monath, Thomas P; Ramsey, W Jay; Link, Charles J; Lane, H Clifford; Michael, Nelson L; Davey, Richard T; Thomas, Stephen J

    2017-01-26

    The worst Ebola virus disease (EVD) outbreak in history has resulted in more than 28,000 cases and 11,000 deaths. We present the final results of two phase 1 trials of an attenuated, replication-competent, recombinant vesicular stomatitis virus (rVSV)-based vaccine candidate designed to prevent EVD. We conducted two phase 1, placebo-controlled, double-blind, dose-escalation trials of an rVSV-based vaccine candidate expressing the glycoprotein of a Zaire strain of Ebola virus (ZEBOV). A total of 39 adults at each site (78 participants in all) were consecutively enrolled into groups of 13. At each site, volunteers received one of three doses of the rVSV-ZEBOV vaccine (3 million plaque-forming units [PFU], 20 million PFU, or 100 million PFU) or placebo. Volunteers at one of the sites received a second dose at day 28. Safety and immunogenicity were assessed. The most common adverse events were injection-site pain, fatigue, myalgia, and headache. Transient rVSV viremia was noted in all the vaccine recipients after dose 1. The rates of adverse events and viremia were lower after the second dose than after the first dose. By day 28, all the vaccine recipients had seroconversion as assessed by an enzyme-linked immunosorbent assay (ELISA) against the glycoprotein of the ZEBOV-Kikwit strain. At day 28, geometric mean titers of antibodies against ZEBOV glycoprotein were higher in the groups that received 20 million PFU or 100 million PFU than in the group that received 3 million PFU, as assessed by ELISA and by pseudovirion neutralization assay. A second dose at 28 days after dose 1 significantly increased antibody titers at day 56, but the effect was diminished at 6 months. This Ebola vaccine candidate elicited anti-Ebola antibody responses. After vaccination, rVSV viremia occurred frequently but was transient. These results support further evaluation of the vaccine dose of 20 million PFU for preexposure prophylaxis and suggest that a second dose may boost antibody responses

  4. Generation and characterization of a novel candidate gene therapy and vaccination vector based on human species D adenovirus type 56.

    Science.gov (United States)

    Duffy, Margaret R; Alonso-Padilla, Julio; John, Lijo; Chandra, Naresh; Khan, Selina; Ballmann, Monika Z; Lipiec, Agnieszka; Heemskerk, Evert; Custers, Jerome; Arnberg, Niklas; Havenga, Menzo; Baker, Andrew H; Lemckert, Angelique

    2018-01-01

    The vectorization of rare human adenovirus (HAdV) types will widen our knowledge of this family and their interaction with cells, tissues and organs. In this study we focus on HAdV-56, a member of human Ad species D, and create ease-of-use cloning systems to generate recombinant HAdV-56 vectors carrying foreign genes. We present in vitro transduction profiles for HAdV-56 in direct comparison to the most commonly used HAdV-5-based vector. In vivo characterizations demonstrate that when it is delivered intravenously (i.v.) HAdV-56 mainly targets the spleen and, to a lesser extent, the lungs, whilst largely bypassing liver transduction in mice. HAdV-56 triggered robust inflammatory and cellular immune responses, with higher induction of IFNγ, TNFα, IL5, IL6, IP10, MCP1 and MIG1 compared to HAdV-5 following i.v. administration. We also investigated its potential as a vaccine vector candidate by performing prime immunizations in mice with HAdV-56 encoding luciferase (HAdV-56-Luc). Direct comparisons were made to HAdV-26, a highly potent human vaccine vector currently in phase II clinical trials. HAdV-56-Luc induced luciferase 'antigen'-specific IFNγ-producing cells and anti-HAdV-56 neutralizing antibodies in Balb/c mice, demonstrating a near identical profile to that of HAdV-26. Taken together, the data presented provides further insight into human Ad receptor/co-receptor usage, and the first report on HAdV-56 vectors and their potential for gene therapy and vaccine applications.

  5. Imperfect Vaccine Aggravates the Long-Standing Dilemma of Voluntary Vaccination

    Science.gov (United States)

    Wu, Bin; Fu, Feng; Wang, Long

    2011-01-01

    Achieving widespread population immunity by voluntary vaccination poses a major challenge for public health administration and practice. The situation is complicated even more by imperfect vaccines. How the vaccine efficacy affects individuals' vaccination behavior has yet to be fully answered. To address this issue, we combine a simple yet effective game theoretic model of vaccination behavior with an epidemiological process. Our analysis shows that, in a population of self-interested individuals, there exists an overshooting of vaccine uptake levels as the effectiveness of vaccination increases. Moreover, when the basic reproductive number, , exceeds a certain threshold, all individuals opt for vaccination for an intermediate region of vaccine efficacy. We further show that increasing effectiveness of vaccination always increases the number of effectively vaccinated individuals and therefore attenuates the epidemic strain. The results suggest that ‘number is traded for efficiency’: although increases in vaccination effectiveness lead to uptake drops due to free-riding effects, the impact of the epidemic can be better mitigated. PMID:21687680

  6. Imperfect vaccine aggravates the long-standing dilemma of voluntary vaccination.

    Directory of Open Access Journals (Sweden)

    Bin Wu

    Full Text Available Achieving widespread population immunity by voluntary vaccination poses a major challenge for public health administration and practice. The situation is complicated even more by imperfect vaccines. How the vaccine efficacy affects individuals' vaccination behavior has yet to be fully answered. To address this issue, we combine a simple yet effective game theoretic model of vaccination behavior with an epidemiological process. Our analysis shows that, in a population of self-interested individuals, there exists an overshooting of vaccine uptake levels as the effectiveness of vaccination increases. Moreover, when the basic reproductive number, R0, exceeds a certain threshold, all individuals opt for vaccination for an intermediate region of vaccine efficacy. We further show that increasing effectiveness of vaccination always increases the number of effectively vaccinated individuals and therefore attenuates the epidemic strain. The results suggest that 'number is traded for efficiency': although increases in vaccination effectiveness lead to uptake drops due to free-riding effects, the impact of the epidemic can be better mitigated.

  7. Major surfome and secretome profile of Streptococcus agalactiae from Nile tilapia (Oreochromis niloticus): Insight into vaccine development.

    Science.gov (United States)

    Li, Wei; Wang, Hai-Qing; He, Run-Zhen; Li, Yan-Wei; Su, You-Lu; Li, An-Xing

    2016-08-01

    Streptococcus agalactiae is a major piscine pathogen that is responsible for huge economic losses to the aquaculture industry. Safe recombinant vaccines, based on a small number of antigenic proteins, are emerging as the most attractive, cost-effective solution against S. agalactiae. The proteins of S. agalactiae exposed to the environment, including surface proteins and secretory proteins, are important targets for the immune system and they are likely to be good vaccine candidates. To obtain a precise profile of its surface proteins, S. agalactiae strain THN0901, which was isolated from tilapia (Oreochromis niloticus), was treated with proteinase K to cleave surface-exposed proteins, which were identified by liquid chromatography-tandem spectrometry (LC-MS/MS). Forty surface-associated proteins were identified, including ten proteins containing cell wall-anchoring motifs, eight lipoproteins, eleven membrane proteins, seven secretory proteins, three cytoplasmic proteins, and one unknown protein. In addition, culture supernatant proteins of S. agalactiae were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and all of the Coomassie-stained bands were subsequently identified by LC-MS/MS. A total of twenty-six extracellular proteins were identified, including eleven secretory proteins, seven cell wall proteins, three membrane proteins, two cytoplasmic proteins and three unknown proteins. Of these, six highly expressed surface-associated and secretory proteins are putative to be vaccine candidate of piscine S. agalactiae. Moreover, immunogenic secreted protein, a highly expressed protein screened from the secretome in the present study, was demonstrated to induce high antibody titer in tilapia, and it conferred protection against S. agalactiae, as evidenced by the relative percent survival (RPS) 48.61± 8.45%. The data reported here narrow the scope of screening protective antigens, and provide guidance in the development of a novel

  8. Evaluation of vaccine candidate potential of deltaaroA, deltahtrA and deltaaroAdeltahtrA mutants of Salmonella enterica subspecies enterica serovar Abortusequi in guinea pigs.

    Science.gov (United States)

    Singh, Bhoj Raj; Chandra, Mudit; Hansda, Dhananjoy; Alam, Javed; Babu, Narayanan; Siddiqui, Mehtab Z; Agrawal, Ravi K; Sharma, Gautam

    2013-04-01

    Salmonella enterica subspecies enterica serovar Abortusequi (S. Abortusequi), a host adapted Salmonella causes abortions, still births and foal mortality in equids. Though known since more than 100 years, it is still a problem in many of the developing countries including India. There is dearth of really good vaccine affording immunity lasting at least for one full gestation. In search of a potential vaccine candidate, three defined deletion mutants (deltaaroA, deltahtrA and deltaaroAdeltahtrA) of S. Abortusequi were tested in guinea pig model for attenuation, safety, immunogenicity, humoral immune response, protective efficacy and persistence in host. The deltahtrA and deltaaroAdeltahtrA mutants were found to be safe on oral inoculation in doses as high as 4.2 x 10(9) cfu/animal. Also through subcutaneous inoculation deltaaroAdeltahtrA mutant did not induce any abortion in pregnant guinea pigs. All the three mutants did not induce any illness or death in 1-2 week-old baby guinea pigs except deltahtrA mutant which caused mortality on intraperitoneal inoculation. Inoculation with mutants protected against challenge and increased breeding efficiency of guinea pigs. After >4.5 months of mutant inoculation, guinea pigs were protected against abortifacient dose of wild type S. Abortusequi and mother guinea pigs also conferred resistance to their babies to the similar challenge. Early humoral immune response of S. Abortusequi mutants was characteristic. Faecal excretion of deltaaroA and htrA mutants was detected up to 45 days of inoculation in guinea pigs while deltaaroAdeltahtrA mutant could not be detected after 21 days of inoculation. The results indicated that the double deletion mutant (deltaaroAdeltahtrA) was the most effective and safe candidate for vaccination against S. Abortusequi through mucosal route of inoculation.

  9. Genetic and phenotypic characterization of manufacturing seeds for a tetravalent dengue vaccine (DENVax.

    Directory of Open Access Journals (Sweden)

    Claire Y-H Huang

    Full Text Available We have developed a manufacturing strategy that can improve the safety and genetic stability of recombinant live-attenuated chimeric dengue vaccine (DENVax viruses. These viruses, containing the pre-membrane (prM and envelope (E genes of dengue serotypes 1-4 in the replicative background of the attenuated dengue-2 PDK-53 vaccine virus candidate, were manufactured under cGMP.After deriving vaccine viruses from RNA-transfected Vero cells, six plaque-purified viruses for each serotype were produced. The plaque-purified strains were then analyzed to select one stock for generation of the master seed. Full genetic and phenotypic characterizations of the master virus seeds were conducted to ensure these viruses retained the previously identified attenuating determinants and phenotypes of the vaccine viruses. We also assessed vector competence of the vaccine viruses in sympatric (Thai Aedes aegypti mosquito vectors.All four serotypes of master vaccine seeds retained the previously defined safety features, including all three major genetic loci of attenuation, small plaques, temperature sensitivity in mammalian cells, reduced replication in mosquito cell cultures, and reduced neurovirulence in new-born mice. In addition, the candidate vaccine viruses demonstrated greatly reduced infection and dissemination in Aedes aegypti mosquitoes, and are not likely to be transmissible by these mosquitoes. This manufacturing strategy has successfully been used to produce the candidate tetravalent vaccine, which is currently being tested in human clinical trials in the United States, Central and South America, and Asia.

  10. Algae-based oral recombinant vaccines

    Science.gov (United States)

    Specht, Elizabeth A.; Mayfield, Stephen P.

    2014-01-01

    Recombinant subunit vaccines are some of the safest and most effective vaccines available, but their high cost and the requirement of advanced medical infrastructure for administration make them impractical for many developing world diseases. Plant-based vaccines have shifted that paradigm by paving the way for recombinant vaccine production at agricultural scale using an edible host. However, enthusiasm for “molecular pharming” in food crops has waned in the last decade due to difficulty in developing transgenic crop plants and concerns of contaminating the food supply. Microalgae could be poised to become the next candidate in recombinant subunit vaccine production, as they present several advantages over terrestrial crop plant-based platforms including scalable and contained growth, rapid transformation, easily obtained stable cell lines, and consistent transgene expression levels. Algae have been shown to accumulate and properly fold several vaccine antigens, and efforts are underway to create recombinant algal fusion proteins that can enhance antigenicity for effective orally delivered vaccines. These approaches have the potential to revolutionize the way subunit vaccines are made and delivered – from costly parenteral administration of purified protein, to an inexpensive oral algae tablet with effective mucosal and systemic immune reactivity. PMID:24596570

  11. Algae-based oral recombinant vaccines

    Directory of Open Access Journals (Sweden)

    Elizabeth A Specht

    2014-02-01

    Full Text Available Recombinant subunit vaccines are some of the safest and most effective vaccines available, but their high cost and the requirement of advanced medical infrastructure for administration make them impractical for many developing world diseases. Plant-based vaccines have shifted that paradigm by paving the way for recombinant vaccine production at agricultural scale using an edible host. However, enthusiasm for molecular pharming in food crops has waned in the last decade due to difficulty in developing transgenic crop plants and concerns of contaminating the food supply. Microalgae are poised to become the next candidate in recombinant subunit vaccine production, and they present several advantages over terrestrial crop plant-based platforms including scalable and contained growth, rapid transformation, easily obtained stable cell lines, and consistent transgene expression levels. Algae have been shown to accumulate and properly fold several vaccine antigens, and efforts are underway to create recombinant algal fusion proteins that can enhance antigenicity for effective orally-delivered vaccines. These approaches have the potential to revolutionize the way subunit vaccines are made and delivered – from costly parenteral administration of purified protein, to an inexpensive oral algae tablet with effective mucosal and system immune reactivity.

  12. Alzheimer's disease: is a vaccine possible?

    International Nuclear Information System (INIS)

    Alves, R.P.S.; Yang, M.J.; Batista, M.T.; Ferreira, L.C.S.

    2014-01-01

    The cause of Alzheimer's disease is still unknown, but the disease is distinctively characterized by the accumulation of β-amyloid plaques and neurofibrillary tangles in the brain. These features have become the primary focus of much of the research looking for new treatments for the disease, including immunotherapy and vaccines targeting β-amyloid in the brain. Adverse effects observed in a clinical trial based on the β-amyloid protein were attributed to the presence of the target antigen and emphasized the relevance of finding safer antigen candidates for active immunization. For this kind of approach, different vaccine formulations using DNA, peptide, and heterologous prime-boost immunization regimens have been proposed. Promising results are expected from different vaccine candidates encompassing B-cell epitopes of the β-amyloid protein. In addition, recent results indicate that targeting another protein involved in the etiology of the disease has opened new perspectives for the effective prevention of the illness. Collectively, the evidence indicates that the idea of finding an effective vaccine for the control of Alzheimer's disease, although not without challenges, is a possibility

  13. Live attenuated vaccines: Historical successes and current challenges

    Energy Technology Data Exchange (ETDEWEB)

    Minor, Philip D., E-mail: Philip.Minor@nibsc.org

    2015-05-15

    Live attenuated vaccines against human viral diseases have been amongst the most successful cost effective interventions in medical history. Smallpox was declared eradicated in 1980; poliomyelitis is nearing global eradication and measles has been controlled in most parts of the world. Vaccines function well for acute diseases such as these but chronic infections such as HIV are more challenging for reasons of both likely safety and probable efficacy. The derivation of the vaccines used has in general not been purely rational except in the sense that it has involved careful clinical trials of candidates and subsequent careful follow up in clinical use; the identification of the candidates is reviewed. - Highlights: • Live vaccines against human diseases caused by viruses have been very successful. • They have been developed by empirical clinical studies and problems identified in later use. • It can be difficult to balance ability to cause disease and ability to immunise for a strain. • There is currently no reliable basis for predicting success from pure virological studies. • Vaccinia, which eradicated smallpox, is the paradigm for all successes and issues.

  14. Live attenuated vaccines: Historical successes and current challenges

    International Nuclear Information System (INIS)

    Minor, Philip D.

    2015-01-01

    Live attenuated vaccines against human viral diseases have been amongst the most successful cost effective interventions in medical history. Smallpox was declared eradicated in 1980; poliomyelitis is nearing global eradication and measles has been controlled in most parts of the world. Vaccines function well for acute diseases such as these but chronic infections such as HIV are more challenging for reasons of both likely safety and probable efficacy. The derivation of the vaccines used has in general not been purely rational except in the sense that it has involved careful clinical trials of candidates and subsequent careful follow up in clinical use; the identification of the candidates is reviewed. - Highlights: • Live vaccines against human diseases caused by viruses have been very successful. • They have been developed by empirical clinical studies and problems identified in later use. • It can be difficult to balance ability to cause disease and ability to immunise for a strain. • There is currently no reliable basis for predicting success from pure virological studies. • Vaccinia, which eradicated smallpox, is the paradigm for all successes and issues

  15. Alzheimer's disease: is a vaccine possible?

    Energy Technology Data Exchange (ETDEWEB)

    Alves, R.P.S. [Universidade de São Paulo, Instituto de Ciências Biomédicas II, Departamento de Microbiologia, Laboratório de Desenvolvimento de Vacinas, São Paulo, SP, Brasil, Laboratório de Desenvolvimento de Vacinas, Departamento de Microbiologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo, São Paulo, SP (Brazil); Yang, M.J. [Instituto Butantan, Laboratório de Genética, São Paulo, SP, Brasil, Laboratório de Genética, Instituto Butantan, São Paulo, SP (Brazil); Batista, M.T.; Ferreira, L.C.S. [Universidade de São Paulo, Instituto de Ciências Biomédicas II, Departamento de Microbiologia, Laboratório de Desenvolvimento de Vacinas, São Paulo, SP, Brasil, Laboratório de Desenvolvimento de Vacinas, Departamento de Microbiologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo, São Paulo, SP (Brazil)

    2014-05-09

    The cause of Alzheimer's disease is still unknown, but the disease is distinctively characterized by the accumulation of β-amyloid plaques and neurofibrillary tangles in the brain. These features have become the primary focus of much of the research looking for new treatments for the disease, including immunotherapy and vaccines targeting β-amyloid in the brain. Adverse effects observed in a clinical trial based on the β-amyloid protein were attributed to the presence of the target antigen and emphasized the relevance of finding safer antigen candidates for active immunization. For this kind of approach, different vaccine formulations using DNA, peptide, and heterologous prime-boost immunization regimens have been proposed. Promising results are expected from different vaccine candidates encompassing B-cell epitopes of the β-amyloid protein. In addition, recent results indicate that targeting another protein involved in the etiology of the disease has opened new perspectives for the effective prevention of the illness. Collectively, the evidence indicates that the idea of finding an effective vaccine for the control of Alzheimer's disease, although not without challenges, is a possibility.

  16. Schistosome syntenin partially protects vaccinated mice against Schistosoma mansoni infection.

    Directory of Open Access Journals (Sweden)

    Barbara C Figueiredo

    2014-08-01

    Full Text Available Schistosomiasis is a neglected tropical disease caused by several species of trematode of the genus Schistosoma. The disease affects more than 200 million people in the world and causes up to 280,000 deaths per year, besides having high morbidity due to chronic illness that damages internal organs. Current schistosomiasis control strategies are mainly based on chemotherapy, but many researchers believe that the best long-term strategy to control disease is a combination of drug treatment and immunization with an anti-schistosome vaccine. Among the most promising molecules as vaccine candidates are the proteins present in the tegument and digestive tract of the parasite.In this study, we describe for the first time Schistosoma mansoni syntenin (SmSynt and we evaluate its potential as a recombinant vaccine. We demonstrate by real-time PCR that syntenin is mainly expressed in intravascular life stages (schistosomula and adult worms of the parasite life cycle and, by confocal microscopy, we localize it in digestive epithelia in adult worms and schistosomula. Administration of siRNAs targeting SmSynt leads to the knock-down of syntenin gene and protein levels, but this has no demonstrable impact on parasite morphology or viability, suggesting that high SmSynt gene expression is not essential for the parasites in vitro. Mice immunization with rSmSynt, formulated with Freund's adjuvant, induces a Th1-type response, as suggested by the production of IFN-γ and TNF-α by rSmSynt-stimulated cultured splenocytes. The protective effect conferred by vaccination with rSmSynt was demonstrated by 30-37% reduction of worm burden, 38-43% reduction in the number, and 35-37% reduction in the area, of liver granulomas.Our report is the first characterization of syntenin in Schistosoma mansoni and our data suggest that this protein is a potential candidate for the development of a multi-antigen vaccine to control schistosomiasis.

  17. Enzymatic shaving of the tegument surface of live schistosomes for proteomic analysis: a rational approach to select vaccine candidates.

    Directory of Open Access Journals (Sweden)

    William Castro-Borges

    2011-03-01

    Full Text Available The membrane-associated and membrane-spanning constituents of the Schistosoma mansoni tegument surface, the parasite's principal interface with the host bloodstream, have recently been characterized using proteomic techniques. Biotinylation of live worms using membrane-impermeant probes revealed that only a small subset of the proteins was accessible to the reagents. Their position within the multilayered architecture of the surface has not been ascertained.An enzymatic shaving approach on live worms has now been used to release the most accessible components, for analysis by MS/MS. Treatment with trypsin, or phosphatidylinositol-specific phospholipase C (PiPLC, only minimally impaired membrane integrity. PiPLC-enriched proteins were distinguished from those released in parasite vomitus or by handling damage, using isobaric tagging. Trypsin released five membrane proteins, Sm200, Sm25 and three annexins, plus host CD44 and the complement factors C3 and C4. Nutrient transporters and ion channels were absent from the trypsin fraction, suggesting a deeper location in the surface complex; surprisingly, two BAR-domain containing proteins were released. Seven parasite and two host proteins were enriched by PiPLC treatment, the vaccine candidate Sm29 being the most prominent along with two orthologues of human CD59, potentially inhibitors of complement fixation. The enzymes carbonic anhydrase and APD-ribosyl cyclase were also enriched, plus Sm200 and alkaline phosphatase. Host GPI-anchored proteins CD48 and CD90, suggest 'surface painting' during worm peregrination in the portal system.Our findings suggest that the membranocalyx secreted over the tegument surface is not the inert barrier previously proposed, some tegument proteins being externally accessible to enzymes and thus potentially located within it. Furthermore, the detection of C3 and C4 indicates that the complement cascade is initiated, while two CD59 orthologues suggest a potential

  18. Protection of yearling ponies against Strongylus vulgaris by foalhood vaccination.

    Science.gov (United States)

    Klei, T R; French, D D; Chapman, M R; McClure, J R; Dennis, V A; Taylor, H W; Hutchinson, G W

    1989-06-01

    The long-term efficacy of an irradiation attenuated larval (L3) vaccine against Strongylus vulgaris was tested in ponies which were reared on pasture. Prior to foaling, mares were divided into two groups. One group of mares and foals received regular (eight weekly) treatment with ivermectin and the second group remained untreated. Half the foals in each pasture group were vaccinated at eight to ten weeks of age. Foals were weaned at three to four months of age and maintained on separate pastures. At eight to ten months of age, ponies were placed in box stalls and half of each treatment group were challenged with S. vulgaris (5 x 1000 L3). Clinical signs and lesions typical of acute verminous arteritis were found at necropsy in the ivermectin treated non-vaccinated challenged yearlings. Ivermectin treated vaccinated challenged yearlings did not show these clinical signs, had markedly reduced to absent arterial lesions and showed an 89 per cent reduction in arterial larval burdens post mortem. Significant differences in clinical signs, arterial lesions or arterial larval burdens were not seen between vaccinated and non-vaccinated foals reared without benefit of ivermectin treatment.

  19. Thermostable cross-protective subunit vaccine against Brucella species.

    Science.gov (United States)

    Cherwonogrodzky, John W; Barabé, Nicole D; Grigat, Michelle L; Lee, William E; Poirier, Robert T; Jager, Scott J; Berger, Bradley J

    2014-12-01

    A subunit vaccine candidate was produced from Brucella suis 145 (biovar 4; expressing both the A antigen of Brucella abortus and the M antigen of Brucella melitensis). The preparation consisted mostly of polysaccharide (PS; >90% [wt/wt]; both cell-associated PS and exo-PS were combined) and a small amount of protein (1 to 3%) with no apparent nucleic acids. Vaccinated mice were protected (these had a statistically significant reduction in bacterial colonization compared to that of unvaccinated controls) when challenged with representative strains of three Brucella species most pathogenic for humans, i.e., B. abortus, B. melitensis, and B. suis. As little as 1 ng of the vaccine, without added adjuvant, protected mice against B. suis 145 infection (5 × 10(5) CFU), and a single injection of 1 μg of this subunit vaccine protected mice from B. suis 145 challenge for at least 14 months. A single immunization induced a serum IgG response to Brucella antigens that remained elevated for up to 9 weeks. The use of heat (i.e., boiling-water bath, autoclaving) in the vaccine preparation showed that it was thermostable. This method also ensured safety and security. The vaccine produced was immunogenic and highly protective against multiple strains of Brucella and represents a promising candidate for further evaluation. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  20. Life course vaccination and healthy aging.

    Science.gov (United States)

    Gusmano, Michael K; Michel, Jean-Pierre

    2009-06-01

    The authors notice the low vaccine coverage rate among European citizens and inventory the multiple reasons leading to the non-use of preventable infectious diseases vaccines in adults whose mortality consequences represent an important and unexpected burden of diseases. These facts are in close relation with the disruption of vaccine recommendations after the childhood vaccine program, the poor literacy knowledge concerning vaccines among the general population, but also unfortunately among physicians and other health care workers. Popular beliefs, fear of side-effects, fear of needles facilitated the constitution of active non-vaccine groups which conduct to the reappearance in non-vaccinated adults and with dramatic consequences of preventable childhood infectious diseases. This careful analysis of the current preventable infectious disease vaccine coverage in old adults leads to propose a life course vaccine programme including adult vaccinations as part of healthy aging as well as old adults' vaccine guidelines integrated in health prevention programs.

  1. Catalase epitopes vaccine design for Helicobacter pylori : A ...

    African Journals Online (AJOL)

    Catalase, an important enzyme in the virulence of H. pylori, could be a suitable candidate for vaccine design because it is highly conserved, which is important for the survival of H. pylori; it is expressed in high level and it is exposed on the surface of the bacteria. In this study, we designed epitope-based vaccine for catalase ...

  2. Malaria vaccines and their potential role in the elimination of malaria

    Directory of Open Access Journals (Sweden)

    Greenwood Brian M

    2008-12-01

    Full Text Available Abstract Research on malaria vaccines is currently directed primarily towards the development of vaccines that prevent clinical malaria. Malaria elimination, now being considered seriously in some epidemiological situations, requires a different vaccine strategy, since success will depend on killing all parasites in the community in order to stop transmission completely. The feature of the life-cycles of human malarias that presents the greatest challenge to an elimination programme is the persistence of parasites as asymptomatic infections. These are an important source from which transmission to mosquitoes can occur. Consequently, an elimination strategy requires a community-based approach covering all individuals and not just those who are susceptible to clinical malaria. The progress that has been made in development of candidate malaria vaccines is reviewed. It is unlikely that many of these will have the efficacy required for complete elimination of parasites, though they may have an important role to play as part of future integrated control programmes. Vaccines for elimination must have a high level of efficacy in order to stop transmission to mosquitoes. This might be achieved with some pre-erythrocytic stage candidate vaccines or by targeting the sexual stages directly with transmission-blocking vaccines. An expanded malaria vaccine programme with such objectives is now a priority.

  3. Status of vaccine research and development of vaccines for leishmaniasis.

    Science.gov (United States)

    Gillespie, Portia M; Beaumier, Coreen M; Strych, Ulrich; Hayward, Tara; Hotez, Peter J; Bottazzi, Maria Elena

    2016-06-03

    A number of leishmaniasis vaccine candidates are at various stages of pre-clinical and clinical development. Leishmaniasis is a vector-borne neglected tropical disease (NTD) caused by a protozoan parasite of the genus Leishmania and transmitted to humans by the bite of a sand fly. Visceral leishmaniasis (VL, kala-azar) is a high mortality NTD found mostly in South Asia and East Africa, while cutaneous leishmaniasis (CL) is a disfiguring NTD highly endemic in the Middle East, Central Asia, North Africa, and the Americas. Estimates attribute 50,000 annual deaths and 3.3 million disability-adjusted life years to leishmaniasis. There are only a few approved drug treatments, no prophylactic drug and no vaccine. Ideally, an effective vaccine against leishmaniasis will elicit long-lasting immunity and protect broadly against VL and CL. Vaccines such as Leish-F1, F2 and F3, developed at IDRI and designed based on selected Leishmania antigen epitopes, have been in clinical trials. Other groups, including the Sabin Vaccine Institute in collaboration with the National Institutes of Health are investigating recombinant Leishmania antigens in combination with selected sand fly salivary gland antigens in order to augment host immunity. To date, both VL and CL vaccines have been shown to be cost-effective in economic modeling studies. Copyright © 2016 World Health Organization. Published by Elsevier Ltd.. All rights reserved.

  4. Virus-like particles as nanovaccine candidates

    International Nuclear Information System (INIS)

    Guillen, G; Aguilar, J C; Dueñas, S; Hermida, L; Iglesias, E; Penton, E; Lobaina, Y; Lopez, M; Mussachio, A; Falcon, V; Alvarez, L; Martinez, G; Gil, L; Valdes, I; Izquierdo, A; Lazo, L; Marcos, E; Guzman, G; Muzio, V; Herrera, L

    2013-01-01

    The existing vaccines are mainly limited to the microorganisms we are able to culture and produce and/or to those whose killing is mediated by humoral response (antibody mediated). It has been more difficult to develop vaccines capable of inducing a functional cellular response needed to prevent or cure chronic diseases. New strategies should be taken into account in the improvement of cell-based immune responses in order to prevent and control the infections and eventually clear the virus. Preclinical and clinical results with vaccine candidates developed as a vaccine platform based on virus-like particles (VLPs) evidenced their ability to stimulate mucosal as well as systemic immunity. Particles based on envelope, membrane or nucleocapsid microbial proteins induce a strong immune response after nasal or parenteral administration in mice, non-human primates and humans. In addition, the immune response obtained was modulated in a Th1 sense. The VLPs were also able to immunoenhance the humoral and cellular immune responses against several viral pathogens. Studies in animals and humans with nasal and systemic formulations evidenced that it is possible to induce functional immune response against HBV, HCV, HIV and dengue virus. (paper)

  5. Development of standardized laboratory methods and quality processes for a phase III study of the RTS, S/AS01 candidate malaria vaccine

    Directory of Open Access Journals (Sweden)

    Carter Terrell

    2011-08-01

    Full Text Available Abstract Background A pivotal phase III study of the RTS,S/AS01 malaria candidate vaccine is ongoing in several research centres across Africa. The development and establishment of quality systems was a requirement for trial conduct to meet international regulatory standards, as well as providing an important capacity strengthening opportunity for study centres. Methods Standardized laboratory methods and quality assurance processes were implemented at each of the study centres, facilitated by funding partners. Results A robust protocol for determination of parasite density based on actual blood cell counts was set up in accordance with World Health Organization recommendations. Automated equipment including haematology and biochemistry analyzers were put in place with standard methods for bedside testing of glycaemia, base excess and lactacidaemia. Facilities for X-rays and basic microbiology testing were also provided or upgraded alongside health care infrastructure in some centres. External quality assurance assessment of all major laboratory methods was established and method qualification by each laboratory demonstrated. The resulting capacity strengthening has ensured laboratory evaluations are conducted locally to the high standards required in clinical trials. Conclusion Major efforts by study centres, together with support from collaborating parties, have allowed standardized methods and robust quality assurance processes to be put in place for the phase III evaluation of the RTS, S/AS01 malaria candidate vaccine. Extensive training programmes, coupled with continuous commitment from research centre staff, have been the key elements behind the successful implementation of quality processes. It is expected these activities will culminate in healthcare benefits for the subjects and communities participating in these trials. Trial registration Clinicaltrials.gov NCT00866619

  6. First results of phase 3 trial of RTS,S/AS01 malaria vaccine in African children

    DEFF Research Database (Denmark)

    Agnandji, Selidji Todagbe; Lell, Bertrand; Soulanoudjingar, Solange Solmeheim

    2011-01-01

    An ongoing phase 3 study of the efficacy, safety, and immunogenicity of candidate malaria vaccine RTS,S/AS01 is being conducted in seven African countries.......An ongoing phase 3 study of the efficacy, safety, and immunogenicity of candidate malaria vaccine RTS,S/AS01 is being conducted in seven African countries....

  7. Malaria vaccines: lessons from field trials

    Directory of Open Access Journals (Sweden)

    Claudio J. Struchiner

    1994-07-01

    Full Text Available Malaria vaccine candidates have already been tested and new trials are being carried out. We present a brief description of specific issues of validity that are relevant when assessing vaccine efficacy in the field and illustrate how the application of these principles might improve our interpretation of the data being gathered in actual malaria vaccine field trials. Our discussion assumes that vaccine evaluation shares the same general principles of validity with epidemiologic causal inference, i.e., the process of drawing inferences from epidemiologic data aiming at the identification of causes of diseases. Judicious exercise of these principles indicates that, for meaningful interpretation, measures of vaccine efficacy require definitions based upon arguments conditional on the amount of exposure to infection, and specification of the initial and final states in which one believes the effect of interest takes place.

  8. Immunogenicity of a Psoralen-Inactivated Dengue Virus Type 1 Vaccine Candidate in Mice

    Science.gov (United States)

    2010-02-01

    United States Naval Medical Research Center Detachment, Lima, Peru , 1 and United States Naval Medical Research Center, Silver Spring, Maryland2 R...and 28. The mice in group B mice received 10-ng vaccine doses on study clays 0, 14, and 28. The mice in group C received 10-ng vaccine doses on

  9. Oral vaccination of wildlife against rabies: Differences among host species in vaccine uptake efficiency.

    Science.gov (United States)

    Vos, Ad; Freuling, Conrad M; Hundt, Boris; Kaiser, Christiane; Nemitz, Sabine; Neubert, Andreas; Nolden, Tobias; Teifke, Jens P; Te Kamp, Verena; Ulrich, Reiner; Finke, Stefan; Müller, Thomas

    2017-07-13

    Oral vaccination using attenuated and recombinant rabies vaccines has been proven a powerful tool to combat rabies in wildlife. However, clear differences have been observed in vaccine titers needed to induce a protective immune response against rabies after oral vaccination in different reservoir species. The mechanisms contributing to the observed resistance against oral rabies vaccination in some species are not completely understood. Hence, the immunogenicity of the vaccine virus strain, SPBN GASGAS, was investigated in a species considered to be susceptible to oral rabies vaccination (red fox) and a species refractory to this route of administration (striped skunk). Additionally, the dissemination of the vaccine virus in the oral cavity was analyzed for these two species. It was shown that the palatine tonsils play a critical role in vaccine virus uptake. Main differences could be observed in palatine tonsil infection between both species, revealing a locally restricted dissemination of infected cells in foxes. The absence of virus infected cells in palatine tonsils of skunks suggests a less efficient uptake of or infection by vaccine virus which may lead to a reduced response to oral vaccination. Understanding the mechanisms of oral resistance to rabies virus vaccine absorption and primary replication may lead to the development of novel strategies to enhance vaccine efficacy in problematic species like the striped skunk. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. A Francisella tularensis live vaccine strain that improves stimulation of antigen-presenting cells does not enhance vaccine efficacy.

    Directory of Open Access Journals (Sweden)

    Deanna M Schmitt

    Full Text Available Vaccination is a proven strategy to mitigate morbidity and mortality of infectious diseases. The methodology of identifying and testing new vaccine candidates could be improved with rational design and in vitro testing prior to animal experimentation. The tularemia vaccine, Francisella tularensis live vaccine strain (LVS, does not elicit complete protection against lethal challenge with a virulent type A Francisella strain. One factor that may contribute to this poor performance is limited stimulation of antigen-presenting cells. In this study, we examined whether the interaction of genetically modified LVS strains with human antigen-presenting cells correlated with effectiveness as tularemia vaccine candidates. Human dendritic cells infected with wild-type LVS secrete low levels of proinflammatory cytokines, fail to upregulate costimulatory molecules, and activate human T cells poorly in vitro. One LVS mutant, strain 13B47, stimulated higher levels of proinflammatory cytokines from dendritic cells and macrophages and increased costimulatory molecule expression on dendritic cells compared to wild type. Additionally, 13B47-infected dendritic cells activated T cells more efficiently than LVS-infected cells. A deletion allele of the same gene in LVS displayed similar in vitro characteristics, but vaccination with this strain did not improve survival after challenge with a virulent Francisella strain. In vivo, this mutant was attenuated for growth and did not stimulate T cell responses in the lung comparable to wild type. Therefore, stimulation of antigen-presenting cells in vitro was improved by genetic modification of LVS, but did not correlate with efficacy against challenge in vivo within this model system.

  11. Vaccine Platforms to Control Arenaviral Hemorrhagic Fevers.

    Science.gov (United States)

    Carrion, Ricardo; Bredenbeek, Peter; Jiang, Xiaohong; Tretyakova, Irina; Pushko, Peter; Lukashevich, Igor S

    2012-11-20

    Arenaviruses are rodent-borne emerging human pathogens. Diseases caused by these viruses, e.g., Lassa fever (LF) in West Africa and South American hemorrhagic fevers (HFs), are serious public health problems in endemic areas. We have employed replication-competent and replication-deficient strategies to design vaccine candidates potentially targeting different groups "at risk". Our leader LF vaccine candidate, the live reassortant vaccine ML29, is safe and efficacious in all tested animal models including non-human primates. In this study we showed that treatment of fatally infected animals with ML29 two days after Lassa virus (LASV) challenge protected 80% of the treated animals. In endemic areas, where most of the target population is poor and many live far from health care facilities, a single-dose vaccination with ML29 would be ideal solution. Once there is an outbreak, a fast-acting vaccine or post-exposure prophylaxis would be best. The 2(nd) vaccine technology is based on Yellow Fever (YF) 17D vaccine. We designed YF17D-based recombinant viruses expressing LASV glycoproteins (GP) and showed protective efficacy of these recombinants. In the current study we developed a novel technology to clone LASV nucleocapsid within YF17D C gene. Low immunogenicity and stability of foreign inserts must be addressed to design successful LASV/YFV bivalent vaccines to control LF and YF in overlapping endemic areas of West Africa. The 3(rd) platform is based on the new generation of alphavirus replicon virus-like-particle vectors (VLPV). Using this technology we designed VLPV expressing LASV GP with enhanced immunogenicity and bivalent VLPV expressing cross-reactive GP of Junin virus (JUNV) and Machupo virus (MACV), causative agents of Argentinian and Bolivian HF, respectively. A prime-boost regimen required for VLPV immunization might be practical for medical providers, military, lab personnel, and visitors in endemic areas.

  12. Identifying protective Streptococcus pyogenes vaccine antigens recognized by both B and T cells in human adults and children

    DEFF Research Database (Denmark)

    Mortensen, Rasmus; Nissen, Thomas Nørrelykke; Fredslund, Sine

    2016-01-01

    No commercial vaccine exists against Group A streptococci (GAS; Streptococcus pyogenes) and only little is known about anti-GAS protective immunity. In our effort to discover new protective vaccine candidates, we selected 21 antigens based on an in silico evaluation. These were all well-conserved......No commercial vaccine exists against Group A streptococci (GAS; Streptococcus pyogenes) and only little is known about anti-GAS protective immunity. In our effort to discover new protective vaccine candidates, we selected 21 antigens based on an in silico evaluation. These were all well...

  13. Histomorphometric characteristics of immune cells in small intestine of pigs perorally immunized with vaccine candidate F18ac+ nonenterotoxigenic E. coli strain

    Directory of Open Access Journals (Sweden)

    I. Valpotic

    2009-12-01

    Full Text Available Colidiarrhea and colienterotoxemia caused by F4+ and/or F18+ enterotoxigenic E. coli (ETEC strains are the most prevalent infections of suckling and weaned pigs. Here we tested the immunogenicity and protective effectiveness of attenuated F18ac+ non-ETEC vaccine candidate strain against challenge infection with F4ac+ ETEC strain by quantitative phenotypic analysis of small intestinal leukocyte subsets in weaned pigs. We also evaluated levamisole as an immune response modifier (IRM and its adjuvanticity when given in the combination with the experimental vaccine. The pigs were parenterally immunized with either levamisole (at days -2, -1 and 0 or with levamisole and perorally given F18ac+ non-ETEC strain (at day 0, and challenged with F4ac+ ETEC strain 7 days later. At day 13 the pigs were euthanatized and sampled for immunohistological/histomorphometrical analyses. Lymphoid CD3+, CD45RA+, CD45RC+, CD21+, IgA+ and myeloid SWC3+ cell subsets were identified in jejunal and ileal epithelium, lamina propria and Peyer’s patches using the avidin-biotin complex method, and their numbers were determined by computer-assisted histomorphometry. Quantitative immunophenotypic analyses showed that levamisole treated pigs had highly increased numbers of jejunal CD3+, CD45RC+ and SWC3+ cells (p<0.05 as compared to those recorded in nontreated control pigs. In the ileum of these pigs we have recorded that only CD21+ cells were significantly increased (p<0.01. The pigs that were treated with levamisole adjuvanted experimental vaccine had significantly increased numbers of all tested cell subsets in both segments of the small intestine. It was concluded that levamisole adjuvanted F18ac+ non-ETEC vaccine was a requirement for the elicitation of protective gut immunity in this model; nonspecific immunization with levamisole was less effective, but confirmed its potential as an IRM.

  14. Economics and financing of vaccines for diarrheal diseases.

    Science.gov (United States)

    Bartsch, Sarah M; Lee, Bruce Y

    2014-01-01

    The considerable burden of infectious disease-caused diarrhea around the world has motivated the continuing development of a number of vaccine candidates over the past several decades with some reaching the market. As with all major public health interventions, understanding the economics and financing of vaccines against diarrheal diseases is essential to their development and implementation. This review focuses on each of the major infectious pathogens that commonly cause diarrhea, the current understanding of their economic burden, the status of vaccine development, and existing economic evaluations of the vaccines. While the literature on the economics and financing of vaccines against diarrhea diseases is growing, there is considerable room for more inquiry. Substantial gaps exist for many pathogens, circumstances, and effects. Economics and financing studies are integral to vaccine development and implementation.

  15. DIVA vaccine properties of the live chimeric pestivirus strain CP7_E2gif

    DEFF Research Database (Denmark)

    von Rosen, Tanya; Rangelova, Desislava Yordanova; Nielsen, Jens

    2014-01-01

    Live modified vaccines to protect against classical swine fever virus (CSFV), based on chimeric pestiviruses, have been developed to enable serological Differentiation of Infected from Vaccinated Animals (DIVA). In this context, the chimeric virus CP7_E2gif vaccine candidate is unique as it does...

  16. Modern Vaccines/Adjuvants Formulation—Session 2 (Plenary II)

    Science.gov (United States)

    Collin, Nicolas

    2013-01-01

    On the 15–17th May 2013, the Fourth International Conference on Modern Vaccines/Adjuvants Formulation was organized in Lausanne, Switzerland, and gathered stakeholders from academics and from the industry to discuss several challenges, advances and promises in the field of vaccine adjuvants. Plenary session 2 of the meeting was composed of four different presentations covering: (1) the recent set-up of an adjuvant technology transfer and training platform in Switzerland, (2) the proposition to revisit existing paradigms of modern vaccinology, (3) the properties of polyethyleneimine as potential new vaccine adjuvant, and (4) the progresses in the design of HIV vaccine candidates able to induce broadly neutralizing antibodies. PMID:23966098

  17. Muc1 based breast cancer vaccines: role of post translational modifications

    International Nuclear Information System (INIS)

    Begum, M.; Khurshid, R.; Nagra, S.A.

    2008-01-01

    Vaccine development is one of the most promising fields in cancer research. After autologous transplantation, due to low tumour burden, patients are more likely to respond immunologically to a cancer vaccine. MUC1 with its adhesive and anti adhesive functions, immunostimulatory and immunosuppressive activities, is therefore a good candidate for breast cancer vaccine. A structure-based insight into the immunogenicity of natural MUC1 glyco forms, of its sub-domains, motifs and post translational modification like glycosylation and myriostoylation may aid the design of tumour vaccines. Primary sequences of human MUC1 were retrieved from the SWISSPROT data bank. Protein pattern search: The primary sequence of Human MUC1 was searched at PROSITE (a dictionary of protein sites and patterns) database. Our study observes that post-translational modifications play an important role in presenting MUC1 as a candidate for breast cancer vaccine. It is found that the phosphorylation and glycosylation of important functional motifs of MUC1 may take part in the production of cytokines that may provide immunization. (author)

  18. Use of Lot Quality Assurance Sampling (LQAS) to estimate vaccination coverage helps guide future vaccination efforts.

    Science.gov (United States)

    Alberti, K P; Guthmann, J P; Fermon, F; Nargaye, K D; Grais, R F

    2008-03-01

    Inadequate evaluation of vaccine coverage after mass vaccination campaigns, such as used in national measles control programmes, can lead to inappropriate public health responses. Overestimation of vaccination coverage may leave populations at risk, whilst underestimation can lead to unnecessary catch-up campaigns. The problem is more complex in large urban areas where vaccination coverage may be heterogeneous and the programme may have to be fine-tuned at the level of geographic subunits. Lack of accurate population figures in many contexts further complicates accurate vaccination coverage estimates. During the evaluation of a mass vaccination campaign carried out in N'Djamena, the capital of Chad, Lot Quality Assurance Sampling was used to estimate vaccination coverage. Using this method, vaccination coverage could be evaluated within smaller geographic areas of the city as well as for the entire city. Despite the lack of accurate population data by neighbourhood, the results of the survey showed heterogeneity of vaccination coverage within the city. These differences would not have been identified using a more traditional method. The results can be used to target areas of low vaccination coverage during follow-up vaccination activities.

  19. Current Peptide and Protein Candidates Challenging HIV Therapy beyond the Vaccine Era

    Directory of Open Access Journals (Sweden)

    Koollawat Chupradit

    2017-09-01

    Full Text Available Human immunodeficiency virus (HIV is a causative agent of acquired immune deficiency syndrome (AIDS. Highly active antiretroviral therapy (HAART can slow down the replication of HIV-1, leading to an improvement in the survival of HIV-1-infected patients. However, drug toxicities and poor drug administration has led to the emergence of a drug-resistant strain. HIV-1 immunotherapy has been continuously developed, but antibody therapy and HIV vaccines take time to improve its efficiency and have limitations. HIV-1-specific chimeric antigen receptor (CAR-based immunotherapy founded on neutralizing antibodies is now being developed. In HIV-1 therapy, anti-HIV chimeric antigen receptors showed promising data in the suppression of HIV-1 replication; however, autologous transfusion is still a problem. This has led to the development of effective peptides and proteins for an alternative HIV-1 treatment. In this paper, we provide a comprehensive review of potent anti-HIV-1 peptides and proteins that reveal promising therapeutic activities. The inhibitory mechanisms of each therapeutic molecule in the different stages of the HIV-1 life cycle will be discussed herein.

  20. Force Spectroscopy of the Plasmodium falciparum Vaccine Candidate Circumsporozoite Protein Suggests a Mechanically Pliable Repeat Region.

    Science.gov (United States)

    Patra, Aditya Prasad; Sharma, Shobhona; Ainavarapu, Sri Rama Koti

    2017-02-10

    The most effective vaccine candidate of malaria is based on the Plasmodium falciparum circumsporozoite protein (CSP), a major surface protein implicated in the structural strength, motility, and immune evasion properties of the infective sporozoites. It is suspected that reversible conformational changes of CSP are required for infection of the mammalian host, but the detailed structure and dynamic properties of CSP remain incompletely understood, limiting our understanding of its function in the infection. Here, we report the structural and mechanical properties of the CSP studied using single-molecule force spectroscopy on several constructs, one including the central region of CSP, which is rich in NANP amino acid repeats (CSP rep ), and a second consisting of a near full-length sequence without the signal and anchor hydrophobic domains (CSP ΔHP ). Our results show that the CSP rep is heterogeneous, with 40% of molecules requiring virtually no mechanical force to unfold (<10 piconewtons (pN)), suggesting that these molecules are mechanically compliant and perhaps act as entropic springs, whereas the remaining 60% are partially structured with low mechanical resistance (∼70 pN). CSP ΔHP having multiple force peaks suggests specifically folded domains, with two major populations possibly indicating the open and collapsed forms. Our findings suggest that the overall low mechanical resistance of the repeat region, exposed on the outer surface of the sporozoites, combined with the flexible full-length conformations of CSP, may provide the sporozoites not only with immune evasion properties, but also with lubricating capacity required during its navigation through the mosquito and vertebrate host tissues. We anticipate that these findings would further assist in the design and development of future malarial vaccines. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. Global Foot-and-Mouth Disease Research Update and Gap Analysis: 3 - Vaccines.

    Science.gov (United States)

    Robinson, L; Knight-Jones, T J D; Charleston, B; Rodriguez, L L; Gay, C G; Sumption, K J; Vosloo, W

    2016-06-01

    This study assessed research knowledge gaps in the field of FMDV (foot-and-mouth disease virus) vaccines. The study took the form of a literature review (2011-15) combined with research updates collected in 2014 from 33 institutes from across the world. Findings were used to identify priority areas for future FMD vaccine research. Vaccines play a vital role in FMD control, used both to limit the spread of the virus during epidemics in FMD-free countries and as the mainstay of disease management in endemic regions, particularly where sanitary controls are difficult to apply. Improvements in the performance or cost-effectiveness of FMD vaccines will allow more widespread and efficient disease control. FMD vaccines have changed little in recent decades, typically produced by inactivation of whole virus, the quantity and stability of the intact viral capsids in the final preparation being key for immunogenicity. However, these are exciting times and several promising novel FMD vaccine candidates have recently been developed. This includes the first FMD vaccine licensed for manufacture and use in the USA; this adenovirus-vectored FMD vaccine causes in vivo expression of viral capsids in vaccinated animals. Another promising vaccine candidate comprises stabilized empty FMDV capsids produced in vitro in a baculovirus expression system. Recombinant technologies are also being developed to improve otherwise conventionally produced inactivated vaccines, for example, by creating a chimeric vaccine virus to increase capsid stability and by inserting sequences into the vaccine virus for desired antigen expression. Other important areas of ongoing research include enhanced adjuvants, vaccine quality control procedures and predicting vaccine protection from immune correlates, thus reducing dependency on animal challenge studies. Globally, the degree of independent vaccine evaluation is highly variable, and this is essential for vaccine quality. Previously neglected, the

  2. Engineering Enhanced Vaccine Cell Lines To Eradicate Vaccine-Preventable Diseases: the Polio End Game.

    Science.gov (United States)

    van der Sanden, Sabine M G; Wu, Weilin; Dybdahl-Sissoko, Naomi; Weldon, William C; Brooks, Paula; O'Donnell, Jason; Jones, Les P; Brown, Cedric; Tompkins, S Mark; Oberste, M Steven; Karpilow, Jon; Tripp, Ralph A

    2016-02-15

    Vaccine manufacturing costs prevent a significant portion of the world's population from accessing protection from vaccine-preventable diseases. To enhance vaccine production at reduced costs, a genome-wide RNA interference (RNAi) screen was performed to identify gene knockdown events that enhanced poliovirus replication. Primary screen hits were validated in a Vero vaccine manufacturing cell line using attenuated and wild-type poliovirus strains. Multiple single and dual gene silencing events increased poliovirus titers >20-fold and >50-fold, respectively. Host gene knockdown events did not affect virus antigenicity, and clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9-mediated knockout of the top candidates dramatically improved viral vaccine strain production. Interestingly, silencing of several genes that enhanced poliovirus replication also enhanced replication of enterovirus 71, a clinically relevant virus to which vaccines are being targeted. The discovery that host gene modulation can markedly increase virus vaccine production dramatically alters mammalian cell-based vaccine manufacturing possibilities and should facilitate polio eradication using the inactivated poliovirus vaccine. Using a genome-wide RNAi screen, a collection of host virus resistance genes was identified that, upon silencing, increased poliovirus and enterovirus 71 production by from 10-fold to >50-fold in a Vero vaccine manufacturing cell line. This report provides novel insights into enterovirus-host interactions and describes an approach to developing the next generation of vaccine manufacturing through engineered vaccine cell lines. The results show that specific gene silencing and knockout events can enhance viral titers of both attenuated (Sabin strain) and wild-type polioviruses, a finding that should greatly facilitate global implementation of inactivated polio vaccine as well as further reduce costs for live-attenuated oral polio vaccines. This work

  3. Lassa virus-like particles displaying all major immunological determinants as a vaccine candidate for Lassa hemorrhagic fever

    Directory of Open Access Journals (Sweden)

    Cashman Kathleen A

    2010-10-01

    virion, electron microscopy analysis demonstrated that LASV VLP appeared structurally similar to native virions, with pleiomorphic distribution in size and shape. LASV VLP that displayed GPC or GPC+NP were immunogenic in mice, and generated a significant IgG response to individual viral proteins over the course of three immunizations, in the absence of adjuvants. Furthermore, sera from convalescent Lassa fever patients recognized VLP in ELISA format, thus affirming the presence of native epitopes displayed by the recombinant pseudoparticles. Conclusions These results established that modular LASV VLP can be generated displaying high levels of immunogenic viral proteins, and that small laboratory scale mammalian expression systems are capable of producing multi-milligram quantities of pseudoparticles. These VLP are structurally and morphologically similar to native LASV virions, but lack replicative functions, and thus can be safely generated in low biosafety level settings. LASV VLP were immunogenic in mice in the absence of adjuvants, with mature IgG responses developing within a few weeks after the first immunization. These studies highlight the relevance of a VLP platform for designing an optimal vaccine candidate against Lassa hemorrhagic fever, and warrant further investigation in lethal challenge animal models to establish their protective potential.

  4. Radiation and Anti-Cancer Vaccines: A Winning Combination.

    Science.gov (United States)

    Cadena, Alexandra; Cushman, Taylor R; Anderson, Clark; Barsoumian, Hampartsoum B; Welsh, James W; Cortez, Maria Angelica

    2018-01-30

    The emerging combination of radiation therapy with vaccines is a promising new treatment plan in the fight against cancer. While many cancer vaccines such as MUC1, p53 CpG oligodeoxynucleotide, and SOX2 may be great candidates for antitumor vaccination, there still remain many investigations to be done into possible vaccine combinations. One fruitful partnership that has emerged are anti-tumor vaccines in combination with radiation. Radiation therapy was previously thought to be only a tool for directly or indirectly damaging DNA and therefore causing cancer cell death. Now, with much preclinical and clinical data, radiation has taken on the role of an in situ vaccine. With both cancer vaccines and radiation at our disposal, more and more studies are looking to combining vaccine types such as toll-like receptors, viral components, dendritic-cell-based, and subunit vaccines with radiation. While the outcomes of these combinatory efforts are promising, there is still much work to be covered. This review sheds light on the current state of affairs in cancer vaccines and how radiation will bring its story into the future.

  5. Potency assay design for adjuvanted recombinant proteins as malaria vaccines.

    Science.gov (United States)

    Giersing, Birgitte K; Dubovsky, Filip; Saul, Allan; Denamur, Francoise; Minor, Philip; Meade, Bruce

    2006-05-15

    Many licensed vaccines are composed of live, attenuated or inactivated whole-cell microorganisms, or they comprise purified components from whole-cell extracts or culture supernatants. For some diseases, pathology is fairly well understood, and there may be known correlates of protection that provide obvious parameters for assessment of vaccine potency. However, this is not always the case, and some effective vaccines are routinely used even though the mechanisms or correlates of protection are unknown. Some more modern vaccine approaches employ purified recombinant proteins, based on molecules that appear on the surface of the pathogen. This is one of the strategies that has been adopted in the quest to develop a malaria vaccine. Use of these parasite antigens as vaccine candidates is supported by substantial epidemiological data, and some have demonstrated the ability to elicit protective responses in animal models of malaria infection. However, there is as yet no immunological correlate of protection and no functional assays or animal models that have demonstrated the ability to predict efficacy in humans. There is little precedence for the most appropriate and practical method for assessing potency of vaccines based on these recombinant molecules for malaria vaccines. This is likely because the majority of malaria vaccine candidates have only recently entered clinical evaluation. The PATH Malaria Vaccine Initiative (MVI) convened a panel with expertise in potency assay design from industry, governmental institutions, and regulatory bodies to discuss and review the rationale, available methods, and best approaches for assessing the potency of recombinant proteins, specifically for their use as malarial vaccines. The aim of this meeting was to produce a discussion document on the practical potency assessment of recombinant protein malaria vaccines, focusing on early phase potency assay development.

  6. A potent Brucella abortus 2308 Δery live vaccine allows for the differentiation between natural and vaccinated infection.

    Science.gov (United States)

    Zhang, Junbo; Yin, Shuanghong; Guo, Fei; Meng, Ren; Chen, Chuangfu; Zhang, Hui; Li, Zhiqiang; Fu, Qiang; Shi, Huijun; Hu, Shengwei; Ni, Wei; Li, Tiansen; Zhang, Ke

    2014-08-01

    Brucellosis is a globally distributed zoonotic disease that causes animal and human diseases. However, the current Brucella abortus vaccines (S19 and RB51) are deficient; they can cause abortion in pregnant animals. Moreover, when the vaccine S19 is used, tests cannot differentiate natural from vaccinated infection. Therefore, a safer and more potent vaccine is needed. A Brucella abortus 2308 ery promoter mutant (Δery) was constructed to overcome these drawbacks. The growth of the Δery mutant was significantly attenuated in macrophages and mice and induced high protective immunity in mice. Moreover, Δery induced an anti-Brucella-specific IgG (immunoglobulin G) response and stimulated the expression of interferon-gamma (INF-γ) and interleukin-4 (IL-4). Furthermore, the expression of EryA antigen allowed for the serological differentiation between natural and vaccinated infection in mice. These results indicate that the Δery mutant is a potential attenuated live vaccine candidate against virulent Brucella abortus 2308 (S2308) infection.

  7. Pediatric invasive pneumococcal disease caused by vaccine serotypes following the introduction of conjugate vaccination in Denmark

    DEFF Research Database (Denmark)

    Harboe, Zitta B; Valentiner-Branth, Palle; Ingels, Helene

    2013-01-01

    A seven-valent pneumococcal conjugate vaccine (PCV7) was introduced in the Danish childhood immunization program (2+1 schedule) in October 2007, followed by PCV13 starting from April 2010. The nationwide incidence of IPD among children younger than 5 years nearly halved after the introduction...... of children suspected to present with a vaccine failure. The period between April 19 and December 31, 2010 was considered a PCV7/PCV13 transitional period, where both vaccines were offered. We identified 45 episodes of IPD caused by a PCV7 serotype (23% of the total number) and 105 (55%) caused by one...... of the 6 additional serotypes in PCV13. Ten children had received at least one PCV7 dose before the onset of IPD caused by a PCV7 serotype. Seven children were considered to be incompletely vaccinated before IPD, but only three cases fulfilled the criteria of vaccine failure (caused by serotypes 14, 19F...

  8. Addition of αGal HyperAcute™ technology to recombinant avian influenza vaccines induces strong low-dose antibody responses.

    Directory of Open Access Journals (Sweden)

    Wenlan Alex Chen

    Full Text Available Highly pathogenic avian influenza represents a severe public health threat. Over the last decade, the demand for highly efficacious vaccines against avian influenza viruses has grown, especially after the 2013 H7N9 outbreak in China that resulted in over 600 human cases with over 200 deaths. Currently, there are several H5N1 and H7N9 influenza vaccines in clinical trials, all of which employ traditional oil-in-water adjuvants due to the poor immunogenicity of avian influenza virus antigens. In this study, we developed potent recombinant avian influenza vaccine candidates using HyperAcute™ Technology, which takes advantage of naturally-acquired anti-αGal immunity in humans. We successfully generated αGal-positive recombinant protein and virus-like particle vaccine candidates of H5N1 and H7N9 influenza strains using either biological or our novel CarboLink chemical αGal modification techniques. Strikingly, two doses of 100 ng αGal-modified vaccine, with no traditional adjuvant, was able to induce a much stronger humoral response in αGT BALB/c knockout mice (the only experimental system readily available for testing αGal in vivo than unmodified vaccines even at 10-fold higher dose (1000 ng/dose. Our data strongly suggest that αGal modification significantly enhances the humoral immunogenicity of the recombinant influenza vaccine candidates. Use of αGal HyperAcute™ technology allows significant dose-sparing while retaining desired immunogenicity. Our success in the development of highly potent H5N1 and H7N9 vaccine candidates demonstrated the potential of αGal HyperAcute™ technology for the development of vaccines against other infectious diseases.

  9. Inactivated rotavirus vaccine induces protective immunity in gnotobiotic piglets.

    Science.gov (United States)

    Wang, Yuhuan; Azevedo, Marli; Saif, Linda J; Gentsch, Jon R; Glass, Roger I; Jiang, Baoming

    2010-07-26

    Live oral rotavirus vaccines that are effective in middle and high income countries have been much less immunogenic and effective among infants in resource-limited settings. Several hypotheses might explain this difference, including neutralization of the vaccine by high levels of maternal antibody in serum and breast milk, severe malnutrition, and interference by other flora and viruses in the gut. We have pursued development of an alternative parenteral rotavirus vaccine with the goal of inducing comparable levels of immunogenicity and efficacy in populations throughout the world regardless of their income levels. In the present study, we assessed the immunogenicity and protection of a candidate inactivated rotavirus vaccine (IRV), the human strain CDC-9 (G1P[8]) formulated with aluminum phosphate, against rotavirus infection in gnotobiotic piglets. Three doses of IRV induced high titers of rotavirus-specific IgG and neutralizing activity in the sera of gnotobiotic piglets and protection against shedding of rotavirus antigen following oral challenge with a homologous virulent human strain Wa (G1P[8]). Our findings demonstrate the proof of concept for an IRV in a large animal model and provide evidence and justification for further clinical development as an alternative candidate vaccine. Published by Elsevier Ltd.

  10. A medically relevant capsular polysaccharide in Acinetobacter baumannii is a potential vaccine candidate.

    Science.gov (United States)

    Yang, Feng-Ling; Lou, Tze-Chi; Kuo, Shu-Chen; Wu, Wan-Ling; Chern, Jeffy; Lee, Yi-Tzu; Chen, Shui-Tsung; Zou, Wei; Lin, Nien-Tsung; Wu, Shih-Hsiung

    2017-03-07

    Concerns of Acinetobacter baumannii infection have increased due to the emergence of multi-drug resistance. In the present study, we determined the capsular polysaccharide (CPS) structure of A. baumannii SK44, a clinical isolate from Taiwan, to consist of pentasaccharide repeats. We found that CPS-induced antibody provided 55% protection against challenge in an animal model. The CPS-specific antibody reacted with the surface components of about 62% clinical isolates (342/554 strains) from cross-sectional and longitudinal studies by dot-immunoassay. Pulsed-field gel electrophoresis of positive strains showed the antibody covered different clonalites of A. baumannii clinical isolates. Meanwhile, using the CPS antibody as a probe, we found a number of outer membrane proteins bound to the antibody, including OmpA/motB, TonB-dependent receptor, and Omp38, indicating their association with CPS. These results might lead to the use of the capsular polysaccharide as a vaccine to prevent A. baumannii infection. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Formalin-inactivated EV71 vaccine candidate induced cross-neutralizing antibody against subgenotypes B1, B4, B5 and C4A in adult volunteers.

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    Ai-Hsiang Chou

    Full Text Available Enterovirus 71 (EV71 has caused several epidemics of hand, foot and mouth diseases (HFMD in Asia. No effective EV71 vaccine is available. A randomized and open-label phase I clinical study registered with ClinicalTrials.gov #NCT01268787, aims to evaluate the safety, reactogenicity and immunogenicity of a formalin-inactivated EV71 vaccine candidate (EV71vac at 5- and 10-µg doses. In this study we report the cross-neutralizing antibody responses from each volunteer against different subgenotypes of EV71 and CVA16.Sixty eligible healthy adults were recruited and vaccinated. Blood samples were obtained on day 0, 21 and 42 and tested against B1, B4, B5, C2, C4A, C4B and CVA16 for cross-neutralizing antibody responses.The immunogenicity of both 5- and 10- µg doses were found to be very similar. Approximately 45% of the participants had 4-fold increase in Nt, but there was no further increase in Nt after the second dose. EV71vac induced very strong cross-neutralizing antibody responses in >85% of volunteers without pre-existing Nt against subgenotype B1, B5 and C4A. EV71vac elicited weak cross-neutralizing antibody responses (∼20% of participants against a C4B and Coxsackie virus A16. Over 90% of vaccinated volunteers did not develop cross-neutralizing antibody responses (Nt<8 against a C2 strain. EV71vac can boost and significantly enhance the neutralizing antibody responses in volunteers who already had pre-vaccination antibodies against EV71 and/or CVA16.EV71vac is efficient in eliciting cross-neutralizing antibody responses against EV71 subgenotypes B1, B4, B5, and C4A, and provides the rationale for its evaluation in phase II clinical trials.ClinicalTrials.gov NCT01268787.

  12. Vaccine-preventable diseases and vaccination rates in South Dakota.

    Science.gov (United States)

    Kightlinger, Lon

    2013-01-01

    Vaccine-preventable diseases have historically caused much illness and death in South Dakota. Sixty-seven diphtheria deaths were reported in 1892 and 1,017 polio cases were reported at the peak of the polio epidemic in 1952. As vaccines have been developed, licensed and put into wide use, the rates of diphtheria, polio, measles, smallpox and other diseases have successfully decreased leading to control, statewide elimination or eradication. Other diseases, such as pertussis, have been more difficult to control by vaccination alone. Although current vaccination coverage rates for South Dakota's kindergarten children surpass the Healthy People 2020 targets of 95 percent, the coverage rates for 2-year-old children and teenagers are below the target rates. Until vaccine-preventable diseases are eradicated globally, we must vigilantly maintain high vaccination coverage rates and aggressively apply control measures to limit transmission when diseases do occur in South Dakota.

  13. Vaccine strategies against schistosomiasis

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    A. Capron

    1992-01-01

    Full Text Available Schistosomiasis, the second major parasitic disease in the world after malaria affects at least 200 million people, 500 million being exposed to the risk of infection. It is widely agreed that a vaccine strategy wich could lead to the induction of effector mechanisms reducing the level of reinfection and ideally parasite fecundity would deeply affect the incidence of pathological manifestations as well as the parasite transmission potentialities. Extensive studies performed in the rat model have allowed the identification of novel effector mechanisms involving IgE antibodies and various inflammatory cell populations (eosinophils, macrophages and platelets whereas regulation of immune response by blocking antibodies has been evidencial. Recent epidemiological studies have now entirely confirmed in human populations the the role of IgE antibodies in the acquisition of resistance and the association of IgG4 blocking antibodies with increased susceptibility. On the basis of these concepts, several schistosome glutathion S-transferase (Sm 28 GST appears as a pronising vaccine candidate. Immunization experiments have shown that two complementary goals can be achieved: (a a partial but significant reduction of the worm population (up to 60//in rats; (b a significant reduction of parasite fecundity (up in the mice and 85//in cattle and egg viability (up to 80//. At least two distinct immunological mechanisms account for these two effects. IgE antibodies appear as a major humoral component of acquired resistance whereas IgA antibodies appear as a major humoral factor affecting parasite fecundity. These studies seem to represent a parasite diseases through the identification of potentially protective antigens and of the components of the immune response which vaccination should aim at inducing.

  14. [Development of current smallpox vaccines].

    Science.gov (United States)

    Maksiutov, R A; Gavrilova, E V; Shchelkunov, S N

    2011-01-01

    The review gives data on the history of smallpox vaccination and shows the high topicality of designing the current safe vaccines against orthopoxviruses. Four generations of live smallpox, protein subunit, and DNA vaccines are considered. Analysis of the data published leads to the conclusion that it is promising to use the up-to-date generations of safe smallpox subunit or DNA vaccines for mass primary immunization with possible further revaccination with classical live vaccine.

  15. Vaccination with Plasmodium knowlesi AMA1 formulated in the novel adjuvant co-vaccine HT™ protects against blood-stage challenge in rhesus macaques.

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    Muzamil Mahdi Abdel Hamid

    Full Text Available Plasmodium falciparum apical membrane antigen 1 (PfAMA1 is a leading blood stage vaccine candidate. Plasmodium knowlesi AMA1 (PkAMA1 was produced and purified using similar methodology as for clinical grade PfAMA1 yielding a pure, conformational intact protein. Combined with the adjuvant CoVaccine HT™, PkAMA1 was found to be highly immunogenic in rabbits and the efficacy of the PkAMA1 was subsequently tested in a rhesus macaque blood-stage challenge model. Six rhesus monkeys were vaccinated with PkAMA1 and a control group of 6 were vaccinated with PfAMA1. A total of 50 µg AMA1 was administered intramuscularly three times at 4 week intervals. One of six rhesus monkeys vaccinated with PkAMA1 was able to control parasitaemia, upon blood stage challenge with P. knowlesi H-strain. Four out of the remaining five showed a delay in parasite onset that correlated with functional antibody titres. In the PfAMA1 vaccinated control group, five out of six animals had to be treated with antimalarials 8 days after challenge; one animal did not become patent during the challenge period. Following a rest period, animals were boosted and challenged again. Four of the six rhesus monkeys vaccinated with PkAMA1 were able to control the parasitaemia, one had a delayed onset of parasitaemia and one animal was not protected, while all control animals required treatment. To confirm that the control of parasitaemia was AMA1-related, animals were allowed to recover, boosted and re-challenged with P. knowlesi Nuri strain. All control animals had to be treated with antimalarials by day 8, while five out of six PkAMA1 vaccinated animals were able to control parasitaemia. This study shows that: i Yeast-expressed PkAMA1 can protect against blood stage challenge; ii Functional antibody levels as measured by GIA correlated inversely with the day of onset and iii GIA IC(50 values correlated with estimated in vivo growth rates.

  16. Unified SU(4) color models in ten dimensions

    International Nuclear Information System (INIS)

    Hanlon, B.E.; Joshi, G.C.

    1992-01-01

    Some aspects of constructing unified models with SU(4) as the color group via a unifying group defined in ten dimensions are examined. Four dimensional theories are recovered using the Coset Space Dimensional Reduction scheme. Candidate models are considered in order to highlight some of the difficulties in constructing realistic four dimensional theories. 30 refs

  17. Vaccine process technology.

    Science.gov (United States)

    Josefsberg, Jessica O; Buckland, Barry

    2012-06-01

    perspective, Quality by Design (QbD) and Process Analytical Technology (PAT) are important initiatives that can be applied effectively to many types of vaccine processes. Universal demand for vaccines requires that a manufacturer plan to supply tens and sometimes hundreds of millions of doses per year at low cost. To enable broader use, there is intense interest in improving temperature stability to allow for excursions from a rigid cold chain supply, especially at the point of vaccination. Finally, there is progress in novel routes of delivery to move away from the traditional intramuscular injection by syringe approach. Copyright © 2012 Wiley Periodicals, Inc.

  18. HIV-1 Gag-specific exosome-targeted T cell-based vaccine stimulates effector CTL responses leading to therapeutic and long-term immunity against Gag/HLA-A2-expressing B16 melanoma in transgenic HLA-A2 mice

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    Rong Wang

    2014-01-01

    Full Text Available Human immunodeficiency virus type-1 (HIV-1-specific dendritic cell (DC vaccines have been applied to clinical trials that show only induction of some degree of immune responses, warranting the search of other more efficient vaccine strategies. Since HIV-1-specific CD8+ cytotoxic T lymphocytes (CTLs have been found to recognize some HIV-1 structural protein Gag conserved and cross-strain epitopes, Gag has become one of the most attractive target candidates for HIV-1 vaccine development. In this study, we generated HIV-1 Gag-specific Gag-Texo vaccine by using ConA-stimulated polyclonal CD8+ T-cells with uptake of Gag-expressing adenoviral vector AdVGag-transfected DC (DCGag-released exosomes (EXOs, and assessed its stimulation of Gag-specific CD8+ CTL responses and antitumor immunity. We demonstrate that Gag-Texo and DCGag vaccines comparably stimulate Gag-specific effector CD8+ CTL responses. Gag-Texo-stimulated CTL responses result in protective immunity against Gag-expressing BL6-10Gag melanoma in 8/8 wild-type C57BL/6 mice. In addition, we show that Gag-Texo vaccine also induces CTL responses leading to protective and long-term immunity against Gag/HLA-A2-expressing BL6-10Gag/A2 melanoma in 8/8 and 2/8 transgenic HLA-A2 mice, respectively. The average number of lung tumor colonies in mice with 30-days post-immunization is only 23, which is significantly less than that (>300 in control ConA-T-immunized HLA-A2 mice. Furthermore, Gag-Texo vaccine also induces some degree of therapeutic immunity. The average number (50 and size (0.23 mm in diameter of lung tumor colonies in Gag-Texo-immunized HLA-A2 mice bearing 6-day-established lung BL6-10Gag/A2 melanoma metastasis are significantly less than the average number (>300 and size (1.02 mm in diameter in control ConA-T-immunized HLA-A2 mice. Taken together, HIV-1 Gag-Texo vaccine capable of stimulating Gag-specific CTL responses and therapeutic immunity may be useful as a new immunotherapeutic

  19. Phase 1b randomized trial and follow-up study in Uganda of the blood-stage malaria vaccine candidate BK-SE36.

    Science.gov (United States)

    Palacpac, Nirianne Marie Q; Ntege, Edward; Yeka, Adoke; Balikagala, Betty; Suzuki, Nahoko; Shirai, Hiroki; Yagi, Masanori; Ito, Kazuya; Fukushima, Wakaba; Hirota, Yoshio; Nsereko, Christopher; Okada, Takuya; Kanoi, Bernard N; Tetsutani, Kohhei; Arisue, Nobuko; Itagaki, Sawako; Tougan, Takahiro; Ishii, Ken J; Ueda, Shigeharu; Egwang, Thomas G; Horii, Toshihiro

    2013-01-01

    Up to now a malaria vaccine remains elusive. The Plasmodium falciparum serine repeat antigen-5 formulated with aluminum hydroxyl gel (BK-SE36) is a blood-stage malaria vaccine candidate that has undergone phase 1a trial in malaria-naive Japanese adults. We have now assessed the safety and immunogenicity of BK-SE36 in a malaria endemic area in Northern Uganda. We performed a two-stage, randomized, single-blinded, placebo-controlled phase 1b trial (Current Controlled trials ISRCTN71619711). A computer-generated sequence randomized healthy subjects for 2 subcutaneous injections at 21-day intervals in Stage1 (21-40 year-olds) to 1-mL BK-SE36 (BKSE1.0) (n = 36) or saline (n = 20) and in Stage2 (6-20 year-olds) to BKSE1.0 (n = 33), 0.5-mL BK-SE36 (BKSE0.5) (n = 33), or saline (n = 18). Subjects and laboratory personnel were blinded. Safety and antibody responses 21-days post-second vaccination (Day42) were assessed. Post-trial, to compare the risk of malaria episodes 130-365 days post-second vaccination, Stage2 subjects were age-matched to 50 control individuals. Nearly all subjects who received BK-SE36 had induration (Stage1, n = 33, 92%; Stage2, n = 63, 96%) as a local adverse event. No serious adverse event related to BK-SE36 was reported. Pre-existing anti-SE36 antibody titers negatively correlated with vaccination-induced antibody response. At Day42, change in antibody titers was significant for seronegative adults (1.95-fold higher than baseline [95% CI, 1.56-2.43], p = 0.004) and 6-10 year-olds (5.71-fold [95% CI, 2.38-13.72], p = 0.002) vaccinated with BKSE1.0. Immunogenicity response to BKSE0.5 was low and not significant (1.55-fold [95% CI, 1.24-1.94], p = 0.75). In the ancillary analysis, cumulative incidence of first malaria episodes with ≥5000 parasites/µL was 7 cases/33 subjects in BKSE1.0 and 10 cases/33 subjects in BKSE0.5 vs. 29 cases/66 subjects in the control group. Risk ratio for BKSE1.0 was 0.48 (95% CI, 0

  20. Shigella vaccine development: prospective animal models and current status.

    Science.gov (United States)

    Kim, Yeon-Jeong; Yeo, Sang-Gu; Park, Jae-Hak; Ko, Hyun-Jeong

    2013-01-01

    Shigella was first discovered in 1897 and is a major causative agent of dysenteric diarrhea. The number of affected patients has decreased globally because of improved sanitary conditions; however, Shigella still causes serious problems in many subjects, including young children and the elderly, especially in developing countries. Although antibiotics may be effective, a vaccine would be the most powerful solution to combat shigellosis because of the emergence of drug-resistant strains. However, the development of a vaccine is hampered by several problems. First, there is no suitable animal model that can replace human-based studies for the investigation of the in vivo mechanisms of Shigella vaccines. Mouse, guinea pig, rat, rabbit, and nonhuman primates could be used as models for shigellosis, but they do not represent human shigellosis and each has its own weaknesses. However, a recent murine model based on peritoneal infection with virulent S. flexneri 2a is promising. Moreover, although the inflammatory responses and mechanisms such as pathogenassociated molecular patterns and danger-associated molecular patterns have been studied, the pathology and immunology of Shigella are still not clearly defined. Despite these obstacles, many vaccine candidates have been developed, including live attenuated, killed whole cells, conjugated, and subunit vaccines. The development of Shigella vaccines also demands considerations of the cost, routes of administration, ease of storage (stability), cross-reactivity, safety, and immunogenicity. The main aim of this review is to provide a detailed introduction to the many promising vaccine candidates and animal models currently available, including the newly developed mouse model.

  1. The synthetic Plasmodium falciparum circumsporozoite peptide PfCS102 as a malaria vaccine candidate: a randomized controlled phase I trial.

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    Régine Audran

    Full Text Available BACKGROUND: Fully efficient vaccines against malaria pre-erythrocytic stage are still lacking. The objective of this dose/adjuvant-finding study was to evaluate the safety, reactogenicity and immunogenicity of a vaccine candidate based on a peptide spanning the C-terminal region of Plasmodium falciparum circumsporozoite protein (PfCS102 in malaria naive adults. METHODOLOGY AND PRINCIPAL FINDINGS: Thirty-six healthy malaria-naive adults were randomly distributed into three dose blocks (10, 30 and 100 microg and vaccinated with PfCS102 in combination with either Montanide ISA 720 or GSK proprietary Adjuvant System AS02A at days 0, 60, and 180. Primary end-point (safety and reactogenicity was based on the frequency of adverse events (AE and of abnormal biological safety tests; secondary-end point (immunogenicity on P. falciparum specific cell-mediated immunity and antibody response before and after immunization. The two adjuvant formulations were well tolerated and their safety profile was good. Most AEs were local and, when systemic, involved mainly fatigue and headache. Half the volunteers in AS02A groups experienced severe AEs (mainly erythema. After the third injection, 34 of 35 volunteers developed anti-PfCS102 and anti-sporozoite antibodies, and 28 of 35 demonstrated T-cell proliferative responses and IFN-gamma production. Five of 22 HLA-A2 and HLA-A3 volunteers displayed PfCS102 specific IFN-gamma secreting CD8(+ T cell responses. Responses were only marginally boosted after the 3(rd vaccination and remained stable for 6 months. For both adjuvants, the dose of 10 microg was less immunogenic in comparison to 30 and 100 microg that induced similar responses. AS02A formulations with 30 microg or 100 microg PfCS102 induced about 10-folds higher antibody and IFN-gamma responses than Montanide formulations. CONCLUSIONS/SIGNIFICANCE: PfCS102 peptide was safe and highly immunogenic, allowing the design of more advanced trials to test its potential

  2. Understanding vaccination resistance: vaccine search term selection bias and the valence of retrieved information.

    Science.gov (United States)

    Ruiz, Jeanette B; Bell, Robert A

    2014-10-07

    Dubious vaccination-related information on the Internet leads some parents to opt out of vaccinating their children. To determine if negative, neutral and positive search terms retrieve vaccination information that differs in valence and confirms searchers' assumptions about vaccination. A content analysis of first-page Google search results was conducted using three negative, three neutral, and three positive search terms for the concepts "vaccine," "vaccination," and "MMR"; 84 of the 90 websites retrieved met inclusion requirements. Two coders independently and reliably coded for the presence or absence of each of 15 myths about vaccination (e.g., "vaccines cause autism"), statements that countered these myths, and recommendations for or against vaccination. Data were analyzed using descriptive statistics. Across all websites, at least one myth was perpetuated on 16.7% of websites and at least one myth was countered on 64.3% of websites. The mean number of myths perpetuated on websites retrieved with negative, neutral, and positive search terms, respectively, was 1.93, 0.53, and 0.40. The mean number of myths countered on websites retrieved with negative, neutral, and positive search terms, respectively, was 3.0, 3.27, and 2.87. Explicit recommendations regarding vaccination were offered on 22.6% of websites. A recommendation against vaccination was more often made on websites retrieved with negative search terms (37.5% of recommendations) than on websites retrieved with neutral (12.5%) or positive (0%) search terms. The concerned parent who seeks information about the risks of childhood immunizations will find more websites that perpetuate vaccine myths and recommend against vaccination than the parent who seeks information about the benefits of vaccination. This suggests that search term valence can lead to online information that supports concerned parents' misconceptions about vaccines. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Peptide-based anti-PCSK9 vaccines - an approach for long-term LDLc management.

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    Gergana Galabova

    Full Text Available Low Density Lipoprotein (LDL hypercholesterolemia, and its associated cardiovascular diseases, are some of the leading causes of death worldwide. The ability of proprotein convertase subtilisin/kexin 9 (PCSK9 to modulate circulating LDL cholesterol (LDLc concentrations made it a very attractive target for LDLc management. To date, the most advanced approaches for PCSK9 inhibition are monoclonal antibody (mAb therapies. Although shown to lower LDLc significantly, mAbs face functional limitations because of their relatively short in vivo half-lives necessitating frequent administration. Here, we evaluated the long-term efficacy and safety of PCSK9-specific active vaccines in different preclinical models.PCSK9 peptide-based vaccines were successfully selected by our proprietary technology. To test their efficacy, wild-type (wt mice, Ldlr+/- mice, and rats were immunized with highly immunogenic vaccine candidates. Vaccines induced generation of high-affine PCSK9-specific antibodies in all species. Group mean total cholesterol (TC concentration was reduced by up to 30%, and LDLc up to 50% in treated animals. Moreover, the PCSK9 vaccine-induced humoral immune response persisted for up to one year in mice, and reduced cholesterol levels significantly throughout the study. Finally, the vaccines were well tolerated in all species tested.Peptide-based anti-PCSK9 vaccines induce the generation of antibodies that are persistent, high-affine, and functional for up to one year. They are powerful and safe tools for long-term LDLc management, and thus may represent a novel therapeutic approach for the prevention and/or treatment of LDL hypercholesterolemia-related cardiovascular diseases in humans.

  4. Development and efficacy of an attenuated Vibrio harveyi vaccine candidate with cross protectivity against Vibrio alginolyticus.

    Science.gov (United States)

    Hu, Yong-hua; Deng, Tian; Sun, Bo-guang; Sun, Li

    2012-06-01

    Vibrio harveyi is a Gram-negative bacterial pathogen that can infect a wide range of marine animals. In previous studies, we have reported a virulent V. harveyi strain, T4D. In the present study, an attenuated mutant of T4D, T4DM, was obtained by selection of rifampicin resistance. Compared to the wild type, T4DM was different in whole-cell protein profile and much slower in growth rate when cultured in stress conditions caused by iron depletion. Virulence analysis showed that compared to T4D, T4DM exhibited a dramatically increased median lethal dose, impaired tissue dissemination capacity, defective hemolytic activity, and significantly reduced resistance against the killing effect of host serum. To examine the potential of T4DM as a live attenuated vaccine, Japanese flounder (Paralichthys olivaceus) were vaccinated with T4DM via intraperitoneal injection or immersion. The results showed that at one and two months post-vaccination, fish administered with T4DM via both approaches, in particular that of immersion, were effectively protected against not only V. harveyi but also Vibrio alginolyticus, another important fish pathogen. Microbiological analysis showed that following immersion vaccination, T4DM was recovered from the internal organs of the vaccinated fish in a time-dependent manner within the first 6 days post-vaccination. Serum antibodies against V. harveyi and V. alginolyticus were detected in T4DM-vaccinated fish, and, compared to serum from control fish, serum from T4DM-vaccinated fish was significantly enhanced in bactericidal activity. These results indicate that T4DM is an attenuated strain with residual infectivity and that T4DM can induce effective cross-species protection against both V. harveyi and V. alginolyticus when used as a live immersion vaccine. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Protection against multiple influenza A virus strains induced by candidate recombinant vaccine based on heterologous M2e peptides linked to flagellin.

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    Liudmila A Stepanova

    Full Text Available Matrix 2 protein ectodomain (M2e is considered a promising candidate for a broadly protective influenza vaccine. M2e-based vaccines against human influenza A provide only partial protection against avian influenza viruses because of differences in the M2e sequences. In this work, we evaluated the possibility of obtaining equal protection and immune response by using recombinant protein on the basis of flagellin as a carrier of the M2e peptides of human and avian influenza A viruses. Recombinant protein was generated by the fusion of two tandem copies of consensus M2e sequence from human influenza A and two copies of M2e from avian A/H5N1 viruses to flagellin (Flg-2M2eh2M2ek. Intranasal immunisation of Balb/c mice with recombinant protein significantly elicited anti-M2e IgG in serum, IgG and sIgA in BAL. Antibodies induced by the fusion protein Flg-2M2eh2M2ek bound efficiently to synthetic peptides corresponding to the human consensus M2e sequence as well as to the M2e sequence of A/Chicken/Kurgan/05/05 RG (H5N1 and recognised native M2e epitopes exposed on the surface of the MDCK cells infected with A/PR/8/34 (H1N1 and A/Chicken/Kurgan/05/05 RG (H5N1 to an equal degree. Immunisation led to both anti-M2e IgG1 and IgG2a response with IgG1 prevalence. We observed a significant intracellular production of IL-4, but not IFN-γ, by CD4+ T-cells in spleen of mice following immunisation with Flg-2M2eh2M2ek. Immunisation with the Flg-2M2eh2M2ek fusion protein provided similar protection from lethal challenge with human influenza A viruses (H1N1, H3N2 and avian influenza virus (H5N1. Immunised mice experienced significantly less weight loss and decreased lung viral titres compared to control mice. The data obtained show the potential for the development of an M2e-flagellin candidate influenza vaccine with broad spectrum protection against influenza A viruses of various origins.

  6. Gut-associated lymphoid tissues for the development of oral vaccines.

    Science.gov (United States)

    Kunisawa, Jun; Kurashima, Yosuke; Kiyono, Hiroshi

    2012-05-01

    Oral vaccine has been considered to be a prospective vaccine against many pathogens especially invading across gastrointestinal tracts. One key element of oral vaccine is targeting efficient delivery of antigen to gut-associated lymphoid tissue (GALT), the inductive site in the intestine where antigen-specific immune responses are initiated. Various chemical and biological antigen delivery systems have been developed and some are in clinical trials. In this review, we describe the immunological features of GALT and the current status of antigen delivery system candidates for successful oral vaccine. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Microbial compositional changes in broiler chicken cecal contents from birds challenged with different Salmonella vaccine candidate strains.

    Science.gov (United States)

    Park, Si Hong; Kim, Sun Ae; Rubinelli, Peter M; Roto, Stephanie M; Ricke, Steven C

    2017-05-31

    Previously, we constructed and characterized the vaccine efficacy of Salmonella Typhimurium mutant strains in poultry with either inducible mviN expression (P BAD -mviN) or methionine auxotrophy (ΔΔmetRmetD). The aim of the present study was to assess potential impact of these Salmonella vaccine strains on the cecal microbiota using a next generation sequencing (NGS). The cecal microbial community obtained from unvaccinated (group 1) and vaccinated chickens (group 2, vaccinated with P BAD -mviN; group 3, vaccinated with wild type; group 4, vaccinated with ΔΔmetRmetD) were subjected to microbiome sequencing analysis with an Illumina MiSeq platform. The NGS microbiome analysis of chicken ceca revealed considerable changes in microbial composition in the presence of the different vaccine strains and exhibited detectable patterns of distinctive clustering among the respective groups (the R value of unweighted PCoA plot was 0.68). The present study indicates that different S. Typhimurium vaccine strains can differentially influence the microbiota of the ceca in terms of presence but not in the relative abundance of microbiota. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Progress towards meningitis prevention in the conjugate vaccines era

    Directory of Open Access Journals (Sweden)

    Cristina Aparecida Borges Laval

    Full Text Available Acute bacterial meningitis is an important cause of morbidity and mortality among children less than five years old. Haemophilus influenzae, Streptococcus pneumoniae and Neisseria meningitidis are the most important agents of bacterial meningitis in developing countries. The development of the conjugate vaccines in the beginning of the 90's, especially type b H. influenzae (Hib, and more recently the heptavalent pneumococcal and the serogroup C meningococcal vaccines, have contributed directly to changes in the epidemiological profile of these invasive diseases (direct effect and of their carriage status (indirect effect. We review the impact of the Hib conjugate vaccine in Latin American countries, where this vaccine has been implemented, and the potential of pneumococcal and meningococcal conjugate vaccines for the reduction of meningitis worldwide. We also address constraints for the development and delivery of these vaccines and review new candidate state-of-the-art vaccines. The greatest challenge, undoubtedly, is to implement these vaccines worldwide, especially in the developing regions.

  9. Development of a chimeric Zika vaccine using a licensed live-attenuated flavivirus vaccine as backbone.

    Science.gov (United States)

    Li, Xiao-Feng; Dong, Hao-Long; Wang, Hong-Jiang; Huang, Xing-Yao; Qiu, Ye-Feng; Ji, Xue; Ye, Qing; Li, Chunfeng; Liu, Yang; Deng, Yong-Qiang; Jiang, Tao; Cheng, Gong; Zhang, Fu-Chun; Davidson, Andrew D; Song, Ya-Jun; Shi, Pei-Yong; Qin, Cheng-Feng

    2018-02-14

    The global spread of Zika virus (ZIKV) and its unexpected association with congenital defects necessitates the rapid development of a safe and effective vaccine. Here we report the development and characterization of a recombinant chimeric ZIKV vaccine candidate (termed ChinZIKV) that expresses the prM-E proteins of ZIKV using the licensed Japanese encephalitis live-attenuated vaccine SA14-14-2 as the genetic backbone. ChinZIKV retains its replication activity and genetic stability in vitro, while exhibiting an attenuation phenotype in multiple animal models. Remarkably, immunization of mice and rhesus macaques with a single dose of ChinZIKV elicits robust and long-lasting immune responses, and confers complete protection against ZIKV challenge. Significantly, female mice immunized with ChinZIKV are protected against placental and fetal damage upon ZIKV challenge during pregnancy. Overall, our study provides an alternative vaccine platform in response to the ZIKV emergency, and the safety, immunogenicity, and protection profiles of ChinZIKV warrant further clinical development.

  10. Evaluation of protective efficacy of three novel H3N2 canine influenza vaccines.

    Science.gov (United States)

    Tu, Liqing; Zhou, Pei; Li, Lutao; Li, Xiuzhen; Hu, Renjun; Jia, Kun; Sun, Lingshuang; Yuan, Ziguo; Li, Shoujun

    2017-11-17

    Canine influenza virus (CIV) has the potential risk to spread in different areas and dog types. Thus, there is a growing need to develop an effective vaccine to control CIV disease. Here, we developed three vaccine candidates: 1) a recombinant pVAX1 vector expressing H3N2 CIV hemagglutinin (pVAX1-HA); 2) a live attenuated canine adenovirus type 2 expressing H3N2 CIV hemagglutinin (rCAV2-HA); and 3) an inactivated H3N2 CIV (A/canine/Guangdong/01/2006 (H3N2)). Mice received an initial intramuscular immunization that followed two booster injections at 2 and 4 weeks post-vaccination (wpv). The splenic lymphocytes were collected to assess the immune responses at 6 wpv. The protective efficacy was evaluated by challenging H3N2 CIV after vaccination (at 6 wpv). Our results demonstrated that all three vaccine candidates elicited cytokine and antibody responses in mice. The rCAV2-HA vaccine and the inactivated vaccine generated efficient protective efficacy in mice, whereas limited protection was provided by the pVAX1-HA DNA vaccine. Therefore, both the rCAV2-HA live recombinant virus and the inactivated CIV could be used as potential novel vaccines against H3N2CIV. This study provides guidance for choosing the most appropriate vaccine for the prevention and control of CIV disease.

  11. Vaccines for HIV | NCI Technology Transfer Center | TTC

    Science.gov (United States)

    The development of an effective HIV vaccine has been an ongoing area of research. The high variability in HIV-1 virus strains has represented a major challenge in successful development. Ideally, an effective candidate vaccine would provide protection against the majority of clades of HIV. Two major hurdles to overcome are immunodominance and sequence diversity. This vaccine utilizes a strategy for overcoming these two issues by identifying the conserved regions of the virus and exploiting them for use in a targeted therapy. NCI seeks licensees and/or research collaborators to commercialize this technology, which has been validated in macaque models.

  12. Assessment of the potential public health impact of Herpes Zoster vaccination in Germany.

    Science.gov (United States)

    Curran, Desmond; Van Oorschot, Desirée; Varghese, Lijoy; Oostvogels, Lidia; Mrkvan, Tomas; Colindres, Romulo; von Krempelhuber, Alfred; Anastassopoulou, Anastassia

    2017-10-03

    The aim of this study was to compare the public health impact of introducing 2 Herpes Zoster (HZ) vaccines, Zoster Vaccine Live (ZVL) versus a non-live adjuvanted subunit candidate vaccine (HZ/su), in the German population aged 50+ years split into 3 age cohorts, i.e. 50-59, 60-69 and 70+ years, respectively. A multi-cohort static Markov model was developed following age cohorts over their lifetime. Demographic data were obtained from the German federal statistical office. HZ incidence and the proportion of HZ individuals developing post-herpetic neuralgia (PHN) were derived from German specific sources. Age-specific vaccine efficacy and waning rates were based on published clinical trial data. Vaccine coverage for both vaccines was assumed to be 40%, with compliance of the second dose of the HZ/su vaccine of 70%. Sensitivity analyses were performed to assess the robustness of the results. It was estimated that, over the remaining lifetime since vaccination, the HZ/su vaccine would reduce the number of HZ cases by 725,233, 533,162 and 486,794 in the 3 age cohorts, respectively, compared with 198,477, 196,000 and 104,640, using ZVL. The number needed to vaccinate (NNV) to prevent one HZ case ranged from 8 to 11 using the HZ/su vaccine compared with 20 to 50 using ZVL. Corresponding NNV to prevent one PHN case ranged from 39 to 53 using the HZ/su vaccine compared with 94 to 198 using ZVL. Due to the higher, sustained vaccine efficacy, the candidate HZ/su vaccine demonstrated superior public health impact compared with ZVL.

  13. Phase 1 safety and immunogenicity evaluation of ADMVA, a multigenic, modified vaccinia Ankara-HIV-1 B'/C candidate vaccine.

    Directory of Open Access Journals (Sweden)

    Sandhya Vasan

    Full Text Available BACKGROUND: We conducted a Phase I dose-escalation trial of ADMVA, a Clade-B'/C-based HIV-1 candidate vaccine expressing env, gag, pol, nef, and tat in a modified vaccinia Ankara viral vector. Sequences were derived from a prevalent circulating HIV-1 recombinant form in Yunnan, China, an area of high HIV incidence. The objective was to evaluate the safety and immunogenicity of ADMVA in human volunteers. METHODOLOGY/PRINCIPAL FINDINGS: ADMVA or placebo was administered intramuscularly at months 0, 1 and 6 to 50 healthy adult volunteers not at high risk for HIV-1. In each dosage group [1x10(7 (low, 5x10(7 (mid, or 2.5x10(8 pfu (high] volunteers were randomized in a 3:1 ratio to receive ADMVA or placebo in a double-blinded design. Subjects were followed for local and systemic reactogenicity, adverse events including cardiac adverse events, and clinical laboratory parameters. Study follow up was 18 months. Humoral immunogenicity was evaluated by anti-gp120 binding ELISA, immunoflourescent staining, and HIV-1 neutralization. Cellular immunogenicity was assessed by a validated IFNgamma ELISpot assay and intracellular cytokine staining. Anti-vaccinia binding titers were measured by ELISA. ADMVA was generally well-tolerated, with no vaccine-related serious adverse events or cardiac adverse events. Local or systemic reactogenicity events were reported by 77% and 78% of volunteers, respectively. The majority of events were of mild intensity. The IFNgamma ELISpot response rate to any HIV antigen was 0/12 (0% in the placebo group, 3/12 (25% in the low dosage group, 6/12 (50% in the mid dosage group, and 8/13 (62% in the high dosage group. Responses were often multigenic and occasionally persisted up to one year post vaccination. Antibodies to gp120 were detected in 0/12 (0%, 8/13 (62%, 6/12 (50% and 10/13 (77% in the placebo, low, mid, and high dosage groups, respectively. Antibodies persisted up to 12 months after vaccination, with a trend toward agreement

  14. Identification of protective antigens for vaccination against systemic salmonellosis

    Directory of Open Access Journals (Sweden)

    Dirk eBumann

    2014-08-01

    Full Text Available There is an urgent medical need for improved vaccines with broad serovar coverage and high efficacy against systemic salmonellosis. Subunit vaccines offer excellent safety profiles but require identification of protective antigens, which remains a challenging task. Here, I review crucial properties of Salmonella antigens that might help to narrow down the number of potential candidates from more than 4000 proteins encoded in Salmonella genomes, to a more manageable number of 50-200 most promising antigens. I also discuss complementary approaches for antigen identification and potential limitations of current pre-clinical vaccine testing.

  15. Development of a multicomponent Staphylococcus aureus vaccine designed to counter multiple bacterial virulence factors

    Science.gov (United States)

    Anderson, Annaliesa S.; Miller, Alita A.; Donald, Robert G.K.; Scully, Ingrid L.; Nanra, Jasdeep S.; Cooper, David; Jansen, Kathrin U.

    2012-01-01

    Staphylococcus aureus is a major cause of healthcare-associated infections and is responsible for a substantial burden of disease in hospitalized patients. Despite increasingly rigorous infection control guidelines, the prevalence and corresponding negative impact of S. aureus infections remain considerable. Difficulties in controlling S. aureus infections as well as the associated treatment costs are exacerbated by increasing rates of resistance to available antibiotics. Despite ongoing efforts over the past 20 years, no licensed S. aureus vaccine is currently available. However, learnings from past clinical failures of vaccine candidates and a better understanding of the immunopathology of S. aureus colonization and infection have aided in the design of new vaccine candidates based on multiple important bacterial pathogenesis mechanisms. This review outlines important considerations in designing a vaccine for the prevention of S. aureus disease in healthcare settings. PMID:22922765

  16. Yellow fever vaccine-associated viscerotropic disease: current perspectives

    OpenAIRE

    Thomas, Roger E

    2016-01-01

    Roger E Thomas Department of Family Medicine, Faculty of Medicine, University of Calgary, Research Office, G012, Health Sciences Centre, Calgary, AB, Canada Purpose: To assess those published cases of yellow fever (YF) vaccine-associated viscerotropic disease that meet the Brighton Collaboration criteria and to assess the safety of YF vaccine with respect to viscerotropic disease. Literature search: Ten electronic databases were searched with no restriction of date or language and r...

  17. Glycoconjugate Vaccines: The Regulatory Framework.

    Science.gov (United States)

    Jones, Christopher

    2015-01-01

    Most vaccines, including the currently available glycoconjugate vaccines, are administered to healthy infants, to prevent future disease. The safety of a prospective vaccine is a key prerequisite for approval. Undesired side effects would not only have the potential to damage the individual infant but also lead to a loss of confidence in the respective vaccine-or vaccines in general-on a population level. Thus, regulatory requirements, particularly with regard to safety, are extremely rigorous. This chapter highlights regulatory aspects on carbohydrate-based vaccines with an emphasis on analytical approaches to ensure the consistent quality of successive manufacturing lots.

  18. The role of human papillomavirus vaccines in cervical cancer: Prevention and treatment.

    Science.gov (United States)

    Bogani, Giorgio; Leone Roberti Maggiore, Umberto; Signorelli, Mauro; Martinelli, Fabio; Ditto, Antonino; Sabatucci, Ilaria; Mosca, Lavinia; Lorusso, Domenica; Raspagliesi, Francesco

    2018-02-01

    Human papillomavirus (HPV) is the most common sexually transmitted disease, worldwide. Primary prevention thorough vaccination si able to reduce the burden of HPV-related lesions. Ten years ago the Food and drug Administration (FDA) approved the first vaccine against HPV. In the last decades, growing data on safety and effectiveness have been collected. In the present review we report the current knowledge on vaccine against HPV, highlighting the current value and prospective regarding the widespread diffusion of HPV vaccines. The role of emerging therapeutic vaccines is reviewed. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Immunomodulators as adjuvants for vaccines and antimicrobial therapy.

    Science.gov (United States)

    Nicholls, Erin F; Madera, Laurence; Hancock, Robert E W

    2010-12-01

    A highly effective strategy for combating infectious diseases is to enhance host defenses using immunomodulators, either preventatively, through vaccination, or therapeutically. The effectiveness of many vaccines currently in use is due in part to adjuvants, molecules that have little immunogenicity by themselves but which help enhance and appropriately skew the immune response to an antigen. The development of new vaccines necessitates the development of new types of adjuvants to ensure an appropriate immune response. Herein, we review commonly used vaccine adjuvants and discuss promising adjuvant candidates. We also discuss various other immunomodulators (namely cytokines, Toll-like receptor agonists, and host defense peptides) that are, or have potential to be, useful for antimicrobial therapies that exert their effects by boosting host immune responses rather than targeting pathogens directly.

  20. Vaccine-induced toxic epidermal necrolysis: A case and systematic review

    OpenAIRE

    Chahal, Dev; Aleshin, Maria; Turegano, Mamina; Chiu, Melvin; Worswick, Scott

    2018-01-01

    Background: Erythema multiforme (EM), Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are cutaneous hypersensitivityreactions that develop in response to specific triggers such as medications and certain infections. Vaccines, which undergo rigorous safety testing prior to use in humans, are a rare cause of SJS/TEN and little is known about the frequency of such events and corresponding pathogenesis. Objective: Herein, we discuss a case of suspected TEN in a 19-yea...

  1. Safety and immunogenicity of a modified-vaccinia-virus-Ankara-based influenza A H5N1 vaccine: a randomised, double-blind phase 1/2a clinical trial.

    Science.gov (United States)

    Kreijtz, Joost H C M; Goeijenbier, Marco; Moesker, Fleur M; van den Dries, Lennert; Goeijenbier, Simone; De Gruyter, Heidi L M; Lehmann, Michael H; Mutsert, Gerrie de; van de Vijver, David A M C; Volz, Asisa; Fouchier, Ron A M; van Gorp, Eric C M; Rimmelzwaan, Guus F; Sutter, Gerd; Osterhaus, Albert D M E

    2014-12-01

    assessed with haemagglutination inhibition geometric mean titre at 8 weeks against H5N1 A/Vietnam/1194/2004 (30·2 [SD 3·8] vs 9·2 [2·3] and 108·1 [2·4] vs 15·8 [3·2]). 27 of 39 eligible individuals were enrolled in the booster immunisation study. A single shot of MVA-H5-sfMR 10(8) pfu prime immunisation resulted in higher antibody responses after the booster immunisation than did two shots of MVA-H5-sfMR at the ten times lower dose. The MVA-based H5N1 vaccine was well tolerated and immunogenic and therefore the vaccine candidates arising from the MVA platform hold great promise for rapid development in response to a future influenza pandemic threat. However, the immunogenicity of this vaccine needs to be compared with conventional H5N1 inactivated non-adjuvanted vaccine candidates in head-to-head clinical trials. European Research Council. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Comparative evaluation of live marker vaccine candidates "CP7_E2alf" and "flc11" along with C-strain "Riems" after oral vaccination

    NARCIS (Netherlands)

    Blome, S.; Aebischer, A.; Lange, E.; Hofmann, M.; Leifer, I.; Loeffen, W.L.A.; Koenen, F.; Beer, M.

    2012-01-01

    Due to the tremendous socio-economic impact of classical swine fever (CSF) outbreaks, emergency vaccination scenarios are continuously under discussion. Unfortunately, all currently available vaccines show restrictions either in terms of marker capacities or immunogenicity. Recent research efforts

  3. Idala: An unnamed Function Peptide Vaccine for Tuberculosis

    African Journals Online (AJOL)

    lysate and injected in mice for immunogenicity experiment up to 42 days. ELISA tests with anti- ... Color development in a microplate reader was ... potential new tuberculosis vaccine candidate. [3]. ..... New York and London: Garland Science,.

  4. Current status and future prospects of yellow fever vaccines.

    Science.gov (United States)

    Beck, Andrew S; Barrett, Alan D T

    2015-01-01

    Yellow fever 17D vaccine is one of the oldest live-attenuated vaccines in current use that is recognized historically for its immunogenic and safe properties. These unique properties of 17D are presently exploited in rationally designed recombinant vaccines targeting not only flaviviral antigens but also other pathogens of public health concern. Several candidate vaccines based on 17D have advanced to human trials, and a chimeric recombinant Japanese encephalitis vaccine utilizing the 17D backbone has been licensed. The mechanism(s) of attenuation for 17D are poorly understood; however, recent insights from large in silico studies have indicated particular host genetic determinants contributing to the immune response to the vaccine, which presumably influences the considerable durability of protection, now in many cases considered to be lifelong. The very rare occurrence of severe adverse events for 17D is discussed, including a recent fatal case of vaccine-associated viscerotropic disease.

  5. Current Status and Future Prospects of Yellow Fever Vaccines

    Science.gov (United States)

    Beck, Andrew S.; Barrett, Alan D.T.

    2017-01-01

    Summary Yellow fever 17D vaccine is one of the oldest live-attenuated vaccines in current use that is recognized for historically immunogenic and safe properties. These unique properties of 17D are presently exploited in rationally designed recombinant vaccines targeting not only flaviviral antigens but also other pathogens of public health concern. Several candidate vaccines based on 17D have advanced to human trials, and a chimeric recombinant Japanese encephalitis vaccine utilizing the 17D backbone has been licensed. The mechanism(s) of attenuation for 17D are poorly understood; however, recent insights from large in silico studies have indicated particular host genetic determinants contributing to the immune response to the vaccine, which presumably influences the considerable durability of protection, now in many cases considered to be life-long. The very rare occurrence of severe adverse events for 17D is discussed, including a recent fatal case of vaccine-associated viscerotropic disease. PMID:26366673

  6. Knowledge and attitudes about human papillomavirus and vaccination

    OpenAIRE

    Silva, Priscila Mendonça Carneiro da; Silva, Izabele Maria Barbosa; Interaminense, Iris Nayara da Conceição Souza; Linhares, Francisca Márcia Pereira; Serrano, Solange Queiroga; Pontes, Cleide Maria

    2018-01-01

    Abstract Objective: Uncover knowledge and attitudes of girls, mothers, teachers and health professionals about human papillomavirus and vaccination. Method: A qualitative study carried out by means of focus groups in public elementary schools and health units of Sanitary District IV from Recife-PE, Brazil, between June and July 2015. The sample was six schoolchildren, ten adolescents, nine mothers, ten teachers, thirteen health professionals and seven community health agents. Speeches were ...

  7. Vaccines against poverty

    Science.gov (United States)

    MacLennan, Calman A.; Saul, Allan

    2014-01-01

    With the 2010s declared the Decade of Vaccines, and Millennium Development Goals 4 and 5 focused on reducing diseases that are potentially vaccine preventable, now is an exciting time for vaccines against poverty, that is, vaccines against diseases that disproportionately affect low- and middle-income countries (LMICs). The Global Burden of Disease Study 2010 has helped better understand which vaccines are most needed. In 2012, US$1.3 billion was spent on research and development for new vaccines for neglected infectious diseases. However, the majority of this went to three diseases: HIV/AIDS, malaria, and tuberculosis, and not neglected diseases. Much of it went to basic research rather than development, with an ongoing decline in funding for product development partnerships. Further investment in vaccines against diarrheal diseases, hepatitis C, and group A Streptococcus could lead to a major health impact in LMICs, along with vaccines to prevent sepsis, particularly among mothers and neonates. The Advanced Market Commitment strategy of the Global Alliance for Vaccines and Immunisation (GAVI) Alliance is helping to implement vaccines against rotavirus and pneumococcus in LMICs, and the roll out of the MenAfriVac meningococcal A vaccine in the African Meningitis Belt represents a paradigm shift in vaccines against poverty: the development of a vaccine primarily targeted at LMICs. Global health vaccine institutes and increasing capacity of vaccine manufacturers in emerging economies are helping drive forward new vaccines for LMICs. Above all, partnership is needed between those developing and manufacturing LMIC vaccines and the scientists, health care professionals, and policy makers in LMICs where such vaccines will be implemented. PMID:25136089

  8. Protective effect of enterovirus‑71 (EV71) virus‑like particle vaccine against lethal EV71 infection in a neonatal mouse model.

    Science.gov (United States)

    Cao, Lei; Mao, Fengfeng; Pang, Zheng; Yi, Yao; Qiu, Feng; Tian, Ruiguang; Meng, Qingling; Jia, Zhiyuan; Bi, Shengli

    2015-08-01

    Enterovirus-71 (EV71) is a viral pathogen that causes severe cases of hand, foot and mouth disease (HFMD) among young children, with significant mortality. Effective vaccines against HFMD are urgently required. Several EV71 virus-like particle (VLP) vaccine candidates were found to be protective in the neonatal mouse EV71 challenge model. However, to what extent the VLP vaccine protects susceptible organs against EV71 infection in vivo has remained elusive. In the present study, the comprehensive immunogenicity of a potential EV71 vaccine candidate based on VLPs was evaluated in a neonatal mouse model. Despite lower levels of neutralizing antibodies to EV71 in the sera of VLP-immunized mice compared with those in mice vaccinated with inactivated EV71, the VLP-based vaccine was shown to be able to induce immunoglobulin (Ig)G and IgA memory-associated cellular immune responses to EV71. Of note, the EV71 VLP vaccine candidate was capable of inhibiting viral proliferation in cardiac muscle, skeletal muscle, lung and intestine of immunized mice and provided effective protection against the pathological damage caused by viral attack. In particular, the VLP vaccine was able to inhibit the transportation of EV71 from the central nervous system to the muscle tissue and greatly protected muscle tissue from infection, along with recovery from the viral infection. This led to nearly 100% immunoprotective efficacy, enabling neonatal mice delivered by VLP-immunized female adult mice to survive and grow with good health. The present study provided valuable additional knowledge of the specific protective efficacy of the EV71 VLP vaccine in vivo, which also indicated that it is a promising potential candidate for being developed into an EV71 vaccine.

  9. A Randomized, Controlled Safety, and Immunogenicity Trial of the M72/AS01 Candidate Tuberculosis Vaccine in HIV-Positive Indian Adults.

    Science.gov (United States)

    Kumarasamy, Nagalingeswaran; Poongulali, Selvamuthu; Bollaerts, Anne; Moris, Philippe; Beulah, Faith Esther; Ayuk, Leo Njock; Demoitié, Marie-Ange; Jongert, Erik; Ofori-Anyinam, Opokua

    2016-01-01

    Human immunodeficiency virus (HIV)-associated tuberculosis is a major public health threat. We evaluated the safety and immunogenicity of the candidate tuberculosis vaccine M72/AS01 in HIV-positive and HIV-negative Indian adults.Randomized, controlled observer-blind trial (NCT01262976).We assigned 240 adults (1:1:1) to antiretroviral therapy (ART)-stable, ART-naive, or HIV-negative cohorts. Cohorts were randomized 1:1 to receive M72/AS01 or placebo following a 0, 1-month schedule and followed for 12 months (time-point M13). HIV-specific and laboratory safety parameters, adverse events (AEs), and M72-specific T-cell-mediated and humoral responses were evaluated.Subjects were predominantly QuantiFERON-negative (60%) and Bacille Calmette-Guérin-vaccinated (73%). Seventy ART-stable, 73 ART-naive, and 60 HIV-negative subjects completed year 1. No vaccine-related serious AEs or ART-regimen adjustments, or clinically relevant effects on laboratory parameters, HIV-1 viral loads or CD4 counts were recorded. Two ART-naive vaccinees died of vaccine-unrelated diseases. M72/AS01 induced polyfunctional M72-specific CD4 T-cell responses (median [interquartile range] at 7 days postdose 2: ART-stable, 0.9% [0.7-1.5]; ART-naive, 0.5% [0.2-1.0]; and HIV-negative, 0.6% [0.4-1.1]), persisting at M13 (0.4% [0.2-0.5], 0.09% [0.04-0.2], and 0.1% [0.09-0.2], respectively). Median responses were higher in the ART-stable cohort versus ART-naive cohort from day 30 onwards (P ≤ 0.015). Among HIV-positive subjects (irrespective of ART-status), median responses were higher in QuantiFERON-positive versus QuantiFERON-negative subjects up to day 30 (P ≤ 0.040), but comparable thereafter. Cytokine-expression profiles were comparable between cohorts after dose 2. At M13, M72-specific IgG responses were higher in ART-stable and HIV-negative vaccinees versus ART-naive vaccinees (P ≤ 0.001).M72/AS01 was well-tolerated and immunogenic in this population of ART-stable and ART-naive HIV

  10. Antigen-displaying lipid-enveloped PLGA nanoparticles as delivery agents for a Plasmodium vivax malaria vaccine.

    Science.gov (United States)

    Moon, James J; Suh, Heikyung; Polhemus, Mark E; Ockenhouse, Christian F; Yadava, Anjali; Irvine, Darrell J

    2012-01-01

    The parasite Plasmodium vivax is the most frequent cause of malaria outside of sub-Saharan Africa, but efforts to develop viable vaccines against P. vivax so far have been inadequate. We recently developed pathogen-mimicking polymeric vaccine nanoparticles composed of the FDA-approved biodegradable polymer poly(lactide-co-glycolide) acid (PLGA) "enveloped" by a lipid membrane. In this study, we sought to determine whether this vaccine delivery platform could be applied to enhance the immune response against P. vivax sporozoites. A candidate malaria antigen, VMP001, was conjugated to the lipid membrane of the particles, and an immunostimulatory molecule, monophosphoryl lipid A (MPLA), was incorporated into the lipid membranes, creating pathogen-mimicking nanoparticle vaccines (VMP001-NPs). Vaccination with VMP001-NPs promoted germinal center formation and elicited durable antigen-specific antibodies with significantly higher titers and more balanced Th1/Th2 responses in vivo, compared with vaccines composed of soluble protein mixed with MPLA. Antibodies raised by NP vaccinations also exhibited enhanced avidity and affinity toward the domains within the circumsporozoite protein implicated in protection and were able to agglutinate live P. vivax sporozoites. These results demonstrate that these VMP001-NPs are promising vaccines candidates that may elicit protective immunity against P. vivax sporozoites.

  11. Antigen-displaying lipid-enveloped PLGA nanoparticles as delivery agents for a Plasmodium vivax malaria vaccine.

    Directory of Open Access Journals (Sweden)

    James J Moon

    Full Text Available The parasite Plasmodium vivax is the most frequent cause of malaria outside of sub-Saharan Africa, but efforts to develop viable vaccines against P. vivax so far have been inadequate. We recently developed pathogen-mimicking polymeric vaccine nanoparticles composed of the FDA-approved biodegradable polymer poly(lactide-co-glycolide acid (PLGA "enveloped" by a lipid membrane. In this study, we sought to determine whether this vaccine delivery platform could be applied to enhance the immune response against P. vivax sporozoites. A candidate malaria antigen, VMP001, was conjugated to the lipid membrane of the particles, and an immunostimulatory molecule, monophosphoryl lipid A (MPLA, was incorporated into the lipid membranes, creating pathogen-mimicking nanoparticle vaccines (VMP001-NPs. Vaccination with VMP001-NPs promoted germinal center formation and elicited durable antigen-specific antibodies with significantly higher titers and more balanced Th1/Th2 responses in vivo, compared with vaccines composed of soluble protein mixed with MPLA. Antibodies raised by NP vaccinations also exhibited enhanced avidity and affinity toward the domains within the circumsporozoite protein implicated in protection and were able to agglutinate live P. vivax sporozoites. These results demonstrate that these VMP001-NPs are promising vaccines candidates that may elicit protective immunity against P. vivax sporozoites.

  12. Design of a Type-1 Diabetes Vaccine Candidate Using Edible Plants Expressing a Major Autoantigen

    Directory of Open Access Journals (Sweden)

    Edoardo Bertini

    2018-05-01

    Full Text Available Type-1 diabetes (T1D is a metabolic disease involving the autoimmune destruction of insulin-producing pancreatic beta cells. It is often diagnosed by the detection of autoantibodies, typically those recognizing insulin itself or the 65-kDa isoform of glutamic acid decarboxylase (GAD65. Oral insulin can be used to induce systemic immunological tolerance and thus prevent or delay the onset of T1D, suggesting that combination treatments with other autoantigens such as GAD65 could be even more successful. GAD65 has induced oral tolerance and prevented T1D in preclinical studies but it is difficult to produce in sufficient quantities for clinical testing. Here we combined edible plant systems, namely spinach (Spinacia oleracea cv Industra and red beet (Beta vulgaris cv Moulin Rouge, with the magnICON® expression system to develop a safe, cost-effective and environmentally sustainable platform for the large-scale production of GAD65. The superior red beet platform was extensively characterized in terms of recombinant protein yields and bioequivalence to wild-type plants, and the product was tested for its ability to resist simulated gastric digestion. Our results indicate that red beet plants are suitable for the production of a candidate oral vaccine based on GAD65 for the future preclinical and clinical testing of T1D immunotherapy approaches.

  13. Introducing dengue vaccine: Implications for diagnosis in dengue vaccinated subjects.

    Science.gov (United States)

    Alagarasu, Kalichamy

    2016-05-27

    Diagnosis of dengue virus infections is complicated by preference for different diagnostic tests in different post onset days of illness and the presence of multiple serotypes leading to secondary and tertiary infections. The sensitivity of the most commonly employed diagnostic assays such as anti dengue IgM capture (MAC) ELISA and non structural protein (NS) 1 capture ELISA are lower in secondary and subsequent infections. Introduction of dengue vaccine in endemic regions will affect the way how dengue is diagnosed in vaccinated subjects. This viewpoint article discusses implications of introduction of dengue vaccine on the diagnosis of dengue infections in vaccinated subjects and the strategies that are needed to tackle the issue. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Parental attitudes to pre-pubertal HPV vaccination.

    Science.gov (United States)

    Marlow, Laura A V; Waller, Jo; Wardle, Jane

    2007-03-01

    To determine the acceptability of childhood HPV vaccination and examine demographic, cultural, and psychosocial predictors of vaccine acceptance. School-based survey. Questionnaires sent to 1205 mothers of 8-14-year-old girls. Responses from 684 were included in the analyses. Ten schools (seven primary, three secondary) in four areas of England. Seventy-five percent of mothers would accept the vaccine for their daughter. Vaccine acceptance was higher in mothers who had experience of cancer in the family (OR=1.61, CI: 1.14-2.29), had older daughters (OR=1.15, CI: 1.04-1.27), perceived approval from husband/partner (OR=14.51, CI: 6.15-34.25) and believed vaccine acceptance would be more normative (OR=1.78, CI: 1.59-2.01). Having concerns about too many vaccinations (OR=0.22, CI: 0.15-0.31) or vaccine side effects (OR=0.37, CI: 0.28-0.50) and worry about increasing promiscuity (OR=0.47, CI: 0.36-0.62) emerged as deterrents. The modal preferred age was 12 years. Endorsing vaccination at earlier ages was predicted by feeling able to discuss related topics, including sex, at younger ages (OR=1.37, CI: 1.24-1.51) and concern about increasing promiscuity (OR=0.61, CI: 0.47-0.78). Overall, there was a favourable response to HPV vaccination. Emphasising the widespread acceptance of the vaccine might promote acceptance further, as would information on immunological and social benefits of earlier vaccination.

  15. The Effectiveness of Anti-R. equi Hyperimmune Plasma against R. equi Challenge in Thoroughbred Arabian Foals of Mares Vaccinated with R. equi Vaccine

    Directory of Open Access Journals (Sweden)

    Osman Erganis

    2014-01-01

    Full Text Available This study aimed to determine the effectiveness of a pregnant mare immunization of a Rhodococcus equi (R. equi vaccine candidate containing a water-based nanoparticle mineral oil adjuvanted (Montanide IMS 3012 inactive bacterin and virulence-associated protein A (VapA, as well as the administration of anti-R. equi hyperimmune (HI plasma against R. equi challenge in the mares’ foals. The efficacy of passive immunizations (colostral passive immunity by mare vaccination and artificial passive immunity by HI plasma administration was evaluated based on clinical signs, complete blood count, blood gas analysis, serological response (ELISA, interleukin-4 (IL-4 and interferon gamma (IFN-γ, total cell count of the bronchoalveolar lavage fluids (BALF samples, reisolation rate of R. equi from BALF samples (CFU/mL, lung samples (CFU/gr, and lesion scores of the organs and tissue according to pathological findings after necropsy in the foals. The vaccination of pregnant mares and HI plasma administration in the foals reduced the severity of R. equi pneumonia and lesion scores of the organs and tissue by 3.54-fold compared to the control foals. This study thus indicates that immunization of pregnant mares with R. equi vaccine candidate and administration of HI plasma in mares’ foals effectively protect foals against R. equi challenge.

  16. Informing vaccine decision-making: A strategic multi-attribute ranking tool for vaccines-SMART Vaccines 2.0.

    Science.gov (United States)

    Knobler, Stacey; Bok, Karin; Gellin, Bruce

    2017-01-20

    SMART Vaccines 2.0 software is being developed to support decision-making among multiple stakeholders in the process of prioritizing investments to optimize the outcomes of vaccine development and deployment. Vaccines and associated vaccination programs are one of the most successful and effective public health interventions to prevent communicable diseases and vaccine researchers are continually working towards expanding targets for communicable and non-communicable diseases through preventive and therapeutic modes. A growing body of evidence on emerging vaccine technologies, trends in disease burden, costs associated with vaccine development and deployment, and benefits derived from disease prevention through vaccination and a range of other factors can inform decision-making and investment in new and improved vaccines and targeted utilization of already existing vaccines. Recognizing that an array of inputs influences these decisions, the strategic multi-attribute ranking method for vaccines (SMART Vaccines 2.0) is in development as a web-based tool-modified from a U.S. Institute of Medicine Committee effort (IOM, 2015)-to highlight data needs and create transparency to facilitate dialogue and information-sharing among decision-makers and to optimize the investment of resources leading to improved health outcomes. Current development efforts of the SMART Vaccines 2.0 framework seek to generate a weighted recommendation on vaccine development or vaccination priorities based on population, disease, economic, and vaccine-specific data in combination with individual preference and weights of user-selected attributes incorporating valuations of health, economics, demographics, public concern, scientific and business, programmatic, and political considerations. Further development of the design and utility of the tool is being carried out by the National Vaccine Program Office of the Department of Health and Human Services and the Fogarty International Center of the

  17. Putative drug and vaccine target protein identification using comparative genomic analysis of KEGG annotated metabolic pathways of Mycoplasma hyopneumoniae.

    Science.gov (United States)

    Damte, Dereje; Suh, Joo-Won; Lee, Seung-Jin; Yohannes, Sileshi Belew; Hossain, Md Akil; Park, Seung-Chun

    2013-07-01

    In the present study, a computational comparative and subtractive genomic/proteomic analysis aimed at the identification of putative therapeutic target and vaccine candidate proteins from Kyoto Encyclopedia of Genes and Genomes (KEGG) annotated metabolic pathways of Mycoplasma hyopneumoniae was performed for drug design and vaccine production pipelines against M.hyopneumoniae. The employed comparative genomic and metabolic pathway analysis with a predefined computational systemic workflow extracted a total of 41 annotated metabolic pathways from KEGG among which five were unique to M. hyopneumoniae. A total of 234 proteins were identified to be involved in these metabolic pathways. Although 125 non homologous and predicted essential proteins were found from the total that could serve as potential drug targets and vaccine candidates, additional prioritizing parameters characterize 21 proteins as vaccine candidate while druggability of each of the identified proteins evaluated by the DrugBank database prioritized 42 proteins suitable for drug targets. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. The human immunodeficiency virus preventive vaccine research at the French National Agency for acquired immunodeficiency syndrome research

    Directory of Open Access Journals (Sweden)

    Elizabeth Fischer

    2005-02-01

    Full Text Available The human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS epidemic is of unprecedented gravity and is spreading rapidly, notably in the most disadvantaged regions of the world. The search for a preventive vaccine is thus an absolute priority. For over 10 years the French National Agency for AIDS research (ANRS has been committed to an original program combining basic science and clinical research. The HIV preventive vaccine research program run by the ANRS covers upstream research for the definition of immunogens, animal models, and clinical research to evaluate candidate vaccines. Most researchers in 2004 believe that it should be possible to obtain partial vaccine protection through the induction of a strong and multiepitopic cellular response. Since 1992, the ANRS has set up 15 phases I and II clinical trials in order to evaluate the safety and the capacity of the candidate vaccines for inducing cellular immune responses. The tested candidate vaccines were increasingly complex recombinant canarypox viruses (Alvac containing sequences coding for certain viral proteins, utilized alone or combined with other immunogens (whole or truncated envelope proteins. ANRS has also been developing an original strategy based on the utilization of lipopeptides. These comprise synthetic fragments of viral proteins associated with lipids that facilitate the induction of a cellular immune response. These approaches promptly allowed the assessment of a prime-boost strategy combining a viral vector and lipopeptides.

  19. Reporting Vaccine Complications: What Do Obstetricians and Gynecologists Know About the Vaccine Adverse Event Reporting System?

    Directory of Open Access Journals (Sweden)

    L. O. Eckert

    2013-01-01

    Full Text Available Background. Obstetrician-gynecologists are increasingly called upon to be vaccinators as an essential part of a woman’s primary and preventive health care. Despite the established safety of vaccines, vaccine adverse events may occur. A national Vaccine Adverse Event Reporting System (VAERS is a well-established mechanism to track adverse events. However, we hypothesized that many obstetrician-gynecologists are naive to the role and use of VAERS. Methods. We devised a ten-question survey to a sample of ACOG fellows to assess their knowledge and understanding of VAERS. We performed descriptive and frequency analysis for each of the questions and used one-way analysis of variance for continuous and chi-squared for categorical variables. Results. Of the 1000 fellows who received the survey, 377 responded. Only one respondent answered all nine knowledge questions correctly, and 9.2% of physicians had used VAERS. Older physicians were less familiar with VAERS in general and with the specific objectives of VAERS in particular (χ2=10.7,P=.005. Conclusions. Obstetrician-gynecologist familiarity with VAERS is lacking. Only when the obstetrician-gynecologist is completely knowledgeable regarding standard vaccine practices, including the availability and use of programs such as VAERS, will providers be functioning as competent and complete vaccinators.

  20. Reproduction of post-weaning multi-systemic wasting syndrome in an animal disease model as a tool for vaccine testing under controlled conditions.

    Science.gov (United States)

    McKillen, John; McNair, Irene; Lagan, Paula; McKay, Karen; McClintock, Julie; Casement, Veronica; Charreyre, Catherine; Allan, Gordon

    2016-04-01

    Snatch farrowed, colostrum deprived piglets were inoculated with different combinations of porcine circovirus 2, porcine parvovirus and Erysipelothrix rhusiopathiae candidate vaccines. 10 piglets were mock-vaccinated. Following virus challenge with a combined porcine circovirus 2/porcine parvovirus inoculum, all animals were monitored and samples taken for serology, immunohistochemistry and qPCR. At 24 dpc all non-vaccinated animals remaining were exhibiting signs of post-weaning multi-systemic wasting syndrome which was confirmed by laboratory analysis. Details of the study, analysis of samples and performance of the candidate vaccines are described. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Classical swine fever vaccines-State-of-the-art.

    Science.gov (United States)

    Blome, Sandra; Moß, Claudia; Reimann, Ilona; König, Patricia; Beer, Martin

    2017-07-01

    Due to its impact on animal health and pig industry, classical swine fever (CSF) is still one of the most important viral diseases of pigs. To control the disease, safe and highly efficacious live attenuated vaccines exist for decades. These vaccines have usually outstanding efficacy and safety but lack differentiability of infected from vaccinated animals (DIVA or marker strategy). In contrast, the first generation of E2 subunit marker vaccines shows constraints in efficacy, application, and production. To overcome these limitations, new generations of marker vaccines are developed. A wide range of approaches have been tried including recombinant vaccines, recombinant inactivated vaccines or subunit vaccines, vector vaccines, and DNA/RNA vaccines. During the last years, especially attenuated deletion vaccines or chimeric constructs have shown potential. At present, especially two new constructs have been intensively tested, the adenovirus-delivered, Semliki Forest virus replicon-vectored marker vaccine candidate "rAdV-SFV-E2" and the pestivirus chimera "CP7_E2alf". The later was recently licensed by the European Medicines Agency. Under field conditions, all marker vaccines have to be accompanied by a potent test system. Particularly this point shows still weaknesses and it is important to embed vaccination in a well-established vaccination strategy and a suitable diagnostic workflow. In summary, conventional vaccines are a standard in terms of efficacy. However, only vaccines with DIVA will allow improved eradication strategies e.g. also under emergency vaccination conditions in free regions. To answer this demand, new generations of marker vaccines have been developed and add now to the tool box of CSF control. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Innovation Partnership for a Roadmap on Vaccines in Europe (IPROVE): A vision for the vaccines of tomorrow.

    Science.gov (United States)

    Medaglini, Donata; De Azero, Magdalena R; Leroy, Odile; Bietrix, Florence; Denoel, Philippe

    2018-02-21

    A clear vision for vaccines research and development (R&D) is needed if Europe is to continue to lead the discovery of next generation vaccines. Innovation Partnership for a Roadmap on Vaccines in Europe (IPROVE) is a collaboration between leading vaccine experts to develop a roadmap setting out how Europe can best invest in the science and technology essential for vaccines innovation. This FP7 project, started in December 2013, brought together more than 130 key public and private stakeholders from academia, public health institutes, regulators, industry and small and medium-sized enterprises to determine and prioritise the gaps and challenges to be addressed to bolster innovation in vaccines and vaccination in Europe. The IPROVE consultation process was structured around seven themes: vaccine R&D, manufacturing and quality control, infrastructure, therapeutic vaccines, needs of small and medium-sized enterprises, vaccines acceptance and training needs. More than 80 recommendations were made by the consultation groups, mainly focused on the need for a multidisciplinary research approach to stimulate innovation, accelerated translation of scientific knowledge into technological innovation, and fostering of real collaboration within the European vaccine ecosystem. The consultation also reinforced the fact that vaccines are only as good as their vaccine implementation programmes, and that more must be done to understand and address vaccination hesitancy of both the general public and healthcare professionals. Bringing together a wide range of stakeholders to work on the IPROVE roadmap has increased mutual understanding of their different perspectives, needs and priorities. IPROVE is a first attempt to develop such a comprehensive view of the vaccine sector. This prioritisation effort, aims to help policy-makers and funders identify those vaccine-related areas and technologies where key investment is needed for short and medium-long term success. Copyright © 2017 The

  3. Gold nanorod vaccine for respiratory syncytial virus

    International Nuclear Information System (INIS)

    Stone, John W; Thornburg, Natalie J; Blum, David L; Kuhn, Sam J; Crowe Jr, James E; Wright, David W

    2013-01-01

    Respiratory syncytial virus (RSV) is a major cause of pneumonia and wheezing in infants and the elderly, but to date there is no licensed vaccine. We developed a gold nanorod construct that displayed the major protective antigen of the virus, the fusion protein (F). Nanorods conjugated to RSV F were formulated as a candidate vaccine preparation by covalent attachment of viral protein using a layer-by-layer approach. In vitro studies using ELISA, electron microscopy and circular dichroism revealed that conformation-dependent epitopes were maintained during conjugation, and transmission electron microscopy studies showed that a dispersed population of particles could be achieved. Human dendritic cells treated with the vaccine induced immune responses in primary human T cells. These results suggest that this vaccine approach may be a potent method for immunizing against viruses such as RSV with surface glycoproteins that are targets for the human immune response. (paper)

  4. Evidence of Bordetella pertussis infection in vaccinated 1-year-old Danish children

    DEFF Research Database (Denmark)

    von Linstow, Marie-Louise; Pontoppidan, Peter Lotko; von König, Carl-Heinz Wirsing

    2010-01-01

    We measured IgA and IgG antibodies to pertussis toxin (PT) and filamentous hemagglutinin (FHA) in sera from 203 1-year-old children who had received one to three doses of a monocomponent PT toxoid vaccine. Ten children (5%) had IgA antibody to PT indicating recent infection; seven of these children......%. The apparent high Bordetella pertussis infection rate in Danish infants suggests that the monocomponent PT toxoid vaccine used in Denmark has limited efficacy against B. pertussis infection. A prospective immunization study comparing a multi-component vaccine with the present monocomponent PT toxoid vaccine...

  5. Dendrimer-conjugated peptide vaccine enhances clearance of Chlamydia trachomatis genital infection.

    Science.gov (United States)

    Ganda, Ingrid S; Zhong, Qian; Hali, Mirabela; Albuquerque, Ricardo L C; Padilha, Francine F; da Rocha, Sandro R P; Whittum-Hudson, Judith A

    2017-07-15

    Peptide-based vaccines have emerged in recent years as promising candidates in the prevention of infectious diseases. However, there are many challenges to maintaining in vivo peptide stability and enhancement of peptide immunogenicity to generate protective immunity which enhances clearance of infections. Here, a dendrimer-based carrier system is proposed for peptide-based vaccine delivery, and shows its anti-microbial feasibility in a mouse model of Chlamydia trachomatis. Chlamydiae are the most prevalent sexually transmitted bacteria worldwide, and also the causal agent of trachoma, the leading cause of preventable infectious blindness. In spite of the prevalence of this infectious agent and the many previous vaccine-related studies, there is no vaccine commercially available. The carrier system proposed consists of generation 4, hydroxyl-terminated, polyamidoamine (PAMAM) dendrimers (G4OH), to which a peptide mimic of a chlamydial glycolipid antigen-Peptide 4 (Pep4, AFPQFRSATLLL) was conjugated through an ester bond. The ester bond between G4OH and Pep4 is expected to break down mainly in the intracellular environment for antigen presentation. Pep4 conjugated to dendrimer induced Chlamydia-specific serum antibodies after subcutaneous immunizations. Further, this new vaccine formulation significantly protected immunized animals from vaginal challenge with infectious Chlamydia trachomatis, and it reduced infectious loads and tissue (genital tract) damage. Pep4 conjugated to G4OH or only mixed with peptide provided enhanced protection compared to Pep4 and adjuvant (i.e. alum), suggesting a potential adjuvant effect of the PAMAM dendrimer. Combined, these results demonstrate that hydroxyl-terminated PAMAM dendrimer is a promising polymeric nanocarrier platform for the delivery of peptide vaccines and this approach has potential to be expanded to other infectious intracellular bacteria and viruses of public health significance. Copyright © 2017 Elsevier B.V. All

  6. Safety and Immunogenicity of a Candidate Parvovirus B19 Vaccine

    OpenAIRE

    Bernstein, David I; El Sahly, Hana M; Keitel, Wendy A; Wolff, Mark; Simone, Gina; Segawa, Claire; Wong, Susan; Shelly, Daniel; Young, Neal S; Dempsey, Walla

    2011-01-01

    Parvovirus B19 is an important human pathogen causing erythema infectiosum, transient aplastic crisis in individuals with underlying hemolytic disorders and hydrops fetalis. We therefore evaluated a parvovirus B19 virus like particle (VLP) vaccine. The safety and immunogenicity of a 25 μg dose of parvovirus B19 recombinant capsid; 2.5 and 25 μg doses of the recombinant capsid given with MF59; and saline placebo were assessed in healthy adults. Because of 3 unexplained cutaneous events the stu...

  7. DENGUE VACCINE, CHALLENGES, DEVELOPMENT AND STRATEGIES

    Directory of Open Access Journals (Sweden)

    Dewi Marbawati

    2014-08-01

    Full Text Available ABSTRAKPenyakit demam Dengue endemik di lebih dari 100 negara di dunia. Obat anti virus Dengue efektif belum ditemukan danpengendalian vektor dinilai kurang efektif, sehingga diperlukan upaya pencegahan dengan vaksinasi. Vaksin Dengue yangideal adalah murah, mencakup 4 serotipe, efektif dalam memberikan kekebalan, cukup diberikan sekali seumur hidup, aman,memberi kekebalan jangka panjang, stabil dalam penyimpanan dan stabil secara genetis (tidak bermutasi. Beberapakandidat vaksin yang telah dan sedang dikembangkan oleh para peneliti di seluruh dunia adalah tetravalent live attenuatedvaccine, vaksin Chimera (ChimeriVax, vaksin subunit dan vaksin DNA. Vaksin Dengue dipandang sebagai pendekatan yangefektif dan berkesinambungan dalam mengendalikan penyakit Dengue. Tahun 2003 telah terbentuk Pediatric DengueVaccine Initiative (PDVI, yaitu sebuah konsorsium internasional yang bergerak dalam advokasi untuk meyakinkanmasyarakat internasional akan penting dan mendesaknya vaksin Dengue. Konsorsium vaksin Dengue Indonesia saat iniberupaya mengembangkan vaksin Dengue dengan menggunakan strain virus lokal.Kata kunci: Dengue, virus, vaksinABSTRACTDengue fever is endemic in more than 100 countries in the world. The effective dengue antiviral drug has not been found yet,and vector control is considered less effective. Prevention program by vaccination is needed. An ideal dengue vaccine shouldbe inexpensive, covering four serotypes (tetravalent, effective in providing immunity, given once a lifetime, safe, stable instorage and genetically. Several vaccine candidates have been and are being developed included attenuated tetravalentvaccine, ChimeriVax, sub- unit vaccines and DNA vaccines. Dengue vaccine is seen as an effective and sustainable approachto controll Dengue infection. In 2003, Pediatric Dengue Vaccine Initiative (PDVI has been formed as an internationalconsortium involved in advocacy to convince the international community about the essence and urgency

  8. Microneedle-mediated delivery of viral vectored vaccines.

    Science.gov (United States)

    Zaric, Marija; Ibarzo Yus, Bárbara; Kalcheva, Petya Petrova; Klavinskis, Linda Sylvia

    2017-10-01

    Microneedle array platforms are a promising technology for vaccine delivery, due to their ease of administration with no sharp waste generated, small size, possibility of targeted delivery to the specified skin depth and efficacious delivery of different vaccine formulations, including viral vectors. Areas covered: Attributes and challenges of the most promising viral vector candidates that have advanced to the clinic and that have been leveraged for skin delivery by microneedles; The importance of understanding the immunobiology of antigen-presenting cells in the skin, in particular dendritic cells, in order to generate further improved skin vaccination strategies; recent studies where viral vectors expressing various antigens have been coupled with microneedle technology to examine their potential for improved vaccination. Expert opinion: Simple, economic and efficacious vaccine delivery methods are needed to improve health outcomes and manage possible outbreaks of new emerging viruses. Understanding what innate/inflammatory signals are required to induce both immediate and long-term responses remains a major hurdle in the development of the effective vaccines. One approach to meet these needs is microneedle-mediated viral vector vaccination. In order for this technology to fulfil this potential the industry must invest significantly to further develop its design, production, biosafety, delivery and large-scale manufacturing.

  9. WHO policy development processes for a new vaccine: case study of malaria vaccines

    Directory of Open Access Journals (Sweden)

    Cheyne James

    2010-06-01

    distribution issues. Conclusions Although policy issues may be more complex for future vaccines, the lead-time between the date of product regulatory approval and a recommendation for its use in developing countries is decreasing. This study presents approaches to define in advance core data needs to support evidence-based decisions, to further decrease this lead-time, accelerating the availability of a malaria vaccine. Specific policy areas for which information should be collected are defined, including studying its use within the context of other malaria interventions.

  10. Recombinant protective antigen 102 (rPA102): profile of a second-generation anthrax vaccine.

    Science.gov (United States)

    Keitel, Wendy A

    2006-08-01

    Recent terrorist attacks involving the use of Bacillus anthracis spores have stimulated interest in the development of new vaccines for anthrax prevention. Studies of the pathogenesis of anthrax and of the immune responses following infection and immunization underscore the pivotal role that antibodies to the protective antigen play in protection. The most promising vaccine candidates contain purified recombinant protective antigen. Clinical trials of one of these, recombinant protective antigen (rPA)102, are underway. Initial results suggest that rPA102 is well tolerated and immunogenic. Additional trials are necessary to identify optimal formulations and immunization regimens for pre- and postexposure prophylaxis. Future licensure of these and other candidate vaccines will depend on their safety and immunogenicity profiles in humans, and their ability to confer protection in animal models of inhalational anthrax.

  11. Biomarkers of safety and immune protection for genetically modified live attenuated leishmania vaccines against visceral leishmaniasis - discovery and implications.

    Science.gov (United States)

    Gannavaram, Sreenivas; Dey, Ranadhir; Avishek, Kumar; Selvapandiyan, Angamuthu; Salotra, Poonam; Nakhasi, Hira L

    2014-01-01

    Despite intense efforts there is no safe and efficacious vaccine against visceral leishmaniasis, which is fatal and endemic in many tropical countries. A major shortcoming in the vaccine development against blood-borne parasitic agents such as Leishmania is the inadequate predictive power of the early immune responses mounted in the host against the experimental vaccines. Often immune correlates derived from in-bred animal models do not yield immune markers of protection that can be readily extrapolated to humans. The limited efficacy of vaccines based on DNA, subunit, heat killed parasites has led to the realization that acquisition of durable immunity against the protozoan parasites requires a controlled infection with a live attenuated organism. Recent success of irradiated malaria parasites as a vaccine candidate further strengthens this approach to vaccination. We developed several gene deletion mutants in Leishmania donovani as potential live attenuated vaccines and reported extensively on the immunogenicity of LdCentrin1 deleted mutant in mice, hamsters, and dogs. Additional limited studies using genetically modified live attenuated Leishmania parasites as vaccine candidates have been reported. However, for the live attenuated parasite vaccines, the primary barrier against widespread use remains the absence of clear biomarkers associated with protection and safety. Recent studies in evaluation of vaccines, e.g., influenza and yellow fever vaccines, using systems biology tools demonstrated the power of such strategies in understanding the immunological mechanisms that underpin a protective phenotype. Applying similar tools in isolated human tissues such as PBMCs from healthy individuals infected with live attenuated parasites such as LdCen(-/-) in vitro followed by human microarray hybridization experiments will enable us to understand how early vaccine-induced gene expression profiles and the associated immune responses are coordinately regulated in normal

  12. Updates on the web-based VIOLIN vaccine database and analysis system.

    Science.gov (United States)

    He, Yongqun; Racz, Rebecca; Sayers, Samantha; Lin, Yu; Todd, Thomas; Hur, Junguk; Li, Xinna; Patel, Mukti; Zhao, Boyang; Chung, Monica; Ostrow, Joseph; Sylora, Andrew; Dungarani, Priya; Ulysse, Guerlain; Kochhar, Kanika; Vidri, Boris; Strait, Kelsey; Jourdian, George W; Xiang, Zuoshuang

    2014-01-01

    The integrative Vaccine Investigation and Online Information Network (VIOLIN) vaccine research database and analysis system (http://www.violinet.org) curates, stores, analyses and integrates various vaccine-associated research data. Since its first publication in NAR in 2008, significant updates have been made. Starting from 211 vaccines annotated at the end of 2007, VIOLIN now includes over 3240 vaccines for 192 infectious diseases and eight noninfectious diseases (e.g. cancers and allergies). Under the umbrella of VIOLIN, >10 relatively independent programs are developed. For example, Protegen stores over 800 protective antigens experimentally proven valid for vaccine development. VirmugenDB annotated over 200 'virmugens', a term coined by us to represent those virulence factor genes that can be mutated to generate successful live attenuated vaccines. Specific patterns were identified from the genes collected in Protegen and VirmugenDB. VIOLIN also includes Vaxign, the first web-based vaccine candidate prediction program based on reverse vaccinology. VIOLIN collects and analyzes different vaccine components including vaccine adjuvants (Vaxjo) and DNA vaccine plasmids (DNAVaxDB). VIOLIN includes licensed human vaccines (Huvax) and veterinary vaccines (Vevax). The Vaccine Ontology is applied to standardize and integrate various data in VIOLIN. VIOLIN also hosts the Ontology of Vaccine Adverse Events (OVAE) that logically represents adverse events associated with licensed human vaccines.

  13. Vaccination and public trust: A model for the dissemination of vaccination behaviour with external intervention

    Science.gov (United States)

    Dorso, Claudio O.; Medus, Andrés; Balenzuela, Pablo

    2017-09-01

    Vaccination is widely recognized as the most effective way of immunization against many infectious diseases. However, unfounded claims about supposed side effects of some vaccines have contributed to spread concern and fear among people, thus inducing vaccination refusal. MMR (Measles, Mumps and Rubella) vaccine coverage has undergone an important decrease in a large part of Europe and US as a consequence of erroneously alleged side effects, leading to recent measles outbreaks. There is evidence that clusterization of unvaccinated individuals may lead to epidemics way larger that the ones that might appear in the case that unvaccinated agents are distributed at random in the population. In this work we explore the emergence of those clusters as a consequence of the social interaction driven mainly by homophily, where vaccination behaviour is part of a process of cultural dissemination in the spirit of Axelrod's model. The ingredients of this calculation encompass: (i) interacting agents which are to decide if they vaccinate or not their children, (ii) their interaction with a small subset of stubborn agents who believe that the MMR vaccine is not safe and (iii) government sponsored propaganda trying to convince people of the benefits of vaccination. We find that these clusters, which emerge as a dynamical outcome of the model, are the responsible of the increasing probability of the occurrence of measles outbreaks, even in scenarios where the WHO (World Health Organization) recommendation of 95% vaccine coverage is fulfilled. However, we also illustrate that the mitigating effect of a public health campaign, could effectively reduce the impact and size of outbreaks.

  14. Cost of goods sold and total cost of delivery for oral and parenteral vaccine packaging formats.

    Science.gov (United States)

    Sedita, Jeff; Perrella, Stefanie; Morio, Matt; Berbari, Michael; Hsu, Jui-Shan; Saxon, Eugene; Jarrahian, Courtney; Rein-Weston, Annie; Zehrung, Darin

    2018-03-14

    Despite limitations of glass packaging for vaccines, the industry has been slow to implement alternative formats. Polymer containers may address many of these limitations, such as breakage and delamination. However, the ability of polymer containers to achieve cost of goods sold (COGS) and total cost of delivery (TCOD) competitive with that of glass containers is unclear, especially for cost-sensitive low- and lower-middle-income countries. COGS and TCOD models for oral and parenteral vaccine packaging formats were developed based on information from subject matter experts, published literature, and Kenya's comprehensive multiyear plan for immunization. Rotavirus and inactivated poliovirus vaccines (IPV) were used as representative examples of oral and parenteral vaccines, respectively. Packaging technologies evaluated included glass vials, blow-fill-seal (BFS) containers, preformed polymer containers, and compact prefilled auto-disable (CPAD) devices in both BFS and preformed formats. For oral vaccine packaging, BFS multi-monodose (MMD) ampoules were the least expensive format, with a COGS of $0.12 per dose. In comparison, oral single-dose glass vials had a COGS of $0.40. BFS MMD ampoules had the lowest TCOD of oral vaccine containers at $1.19 per dose delivered, and ten-dose glass vials had a TCOD of $1.61 per dose delivered. For parenteral vaccines, the lowest COGS was achieved with ten-dose glass vials at $0.22 per dose. In contrast, preformed CPAD devices had the highest COGS at $0.60 per dose. Ten-dose glass vials achieved the lowest TCOD of the parenteral vaccine formats at $1.56 per dose delivered. Of the polymer containers for parenteral vaccines, BFS MMD ampoules achieved the lowest TCOD at $1.89 per dose delivered, whereas preformed CPAD devices remained the most expensive format, at $2.25 per dose delivered. Given their potential to address the limitations of glass and reduce COGS and TCOD, polymer containers deserve further consideration as alternative

  15. Phase I trial of RV3-BB rotavirus vaccine: a human neonatal rotavirus vaccine.

    Science.gov (United States)

    Danchin, M; Kirkwood, C D; Lee, K J; Bishop, R F; Watts, E; Justice, F A; Clifford, V; Cowley, D; Buttery, J P; Bines, J E

    2013-05-28

    RV3 is a human neonatal rotavirus strain (G3P[6]) that has been associated with asymptomatic neonatal infection and replicates well in the infant gut. RV3-BB rotavirus vaccine has been developed as a rotavirus vaccine candidate for administration at birth. A single-centre, double-blind, randomised placebo-controlled Phase I study evaluated the safety and tolerability of a single oral dose of the second generation RV3-BB rotavirus vaccine (8.3×10(6)FFU/mL) in 20 adults, 20 children and 20 infants (10 vaccine and 10 placebo per age cohort). Vaccine take was defined as seroconversion (a 3-fold increase in serum anti-rotavirus IgA or serum neutralising antibody (SNA) from baseline at day 28 post-dose) or evidence of RV3-BB viral replication in the faeces by RT-PCR analysis 3-6 days post-vaccination. RV3-BB presence was confirmed by sequence analysis. The RV3-BB vaccine was well tolerated in all participants, with no pattern of adverse events shown to be associated with the study vaccine. In the infant cohort, vaccine take was demonstrated in 8/9 infants following a single dose of vaccine compared with 2/7 placebo recipients. In the infant vaccine group, 5/9 infants exhibited either IgA or SNA seroconversion and 7/9 infants had evidence of RV3-BB replication on days 3-6, compared with 2/7 infants who seroconverted and 0/10 infants with evidence of replication in the placebo group. Two infants in the placebo group had serological evidence of a rotavirus infection within the 28-day study period: one demonstrated an IgA and the other an SNA response, with wild-type virus replication detected in another infant. A single dose of RV3-BB rotavirus vaccine was well tolerated in adults, children and infants. Most infants (8/9) who received RV3-BB demonstrated vaccine take following a single dose. These data support progression of RV3-BB to Phase II immunogenicity and efficacy trials. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Influence of demographic changes on the impact of vaccination against varicella and herpes zoster in Germany - a mathematical modelling study.

    Science.gov (United States)

    Horn, Johannes; Damm, Oliver; Greiner, Wolfgang; Hengel, Hartmut; Kretzschmar, Mirjam E; Siedler, Anette; Ultsch, Bernhard; Weidemann, Felix; Wichmann, Ole; Karch, André; Mikolajczyk, Rafael T

    2018-01-09

    Epidemiological studies suggest that reduced exposure to varicella might lead to an increased risk for herpes zoster (HZ). Reduction of exposure to varicella is a consequence of varicella vaccination but also of demographic changes. We analyzed how the combination of vaccination programs and demographic dynamics will affect the epidemiology of varicella and HZ in Germany over the next 50 years. We used a deterministic dynamic compartmental model to assess the impact of different varicella and HZ vaccination strategies on varicella and HZ epidemiology in three demographic scenarios, namely the projected population for Germany, the projected population additionally accounting for increased immigration as observed in 2015/2016, and a stationary population. Projected demographic changes alone result in an increase of annual HZ cases by 18.3% and a decrease of varicella cases by 45.7% between 1990 and 2060. Independently of the demographic scenario, varicella vaccination reduces the cumulative number of varicella cases until 2060 by approximately 70%, but also increases HZ cases by 10%. Unlike the currently licensed live attenuated HZ vaccine, the new subunit vaccine candidate might completely counteract this effect. Relative vaccine effects were consistent across all demographic scenarios. Demographic dynamics will be a major determinant of HZ epidemiology in the next 50 years. While stationary population models are appropriate for assessing vaccination impact, models incorporating realistic population structures allow a direct comparison to surveillance data and can thus provide additional input for immunization decision-making and resource planning.

  17. Clinical development of placental malaria vaccines and immunoassays harmonization

    DEFF Research Database (Denmark)

    Chêne, Arnaud; Houard, Sophie; Nielsen, Morten A

    2016-01-01

    Placental malaria caused by Plasmodium falciparum infection constitutes a major health problem manifesting as severe disease and anaemia in the mother, impaired fetal development, low birth weight or spontaneous abortion. Prevention of placental malaria currently relies on two key strategies...... that are losing efficacy due to spread of resistance: long-lasting insecticide-treated nets and intermittent preventive treatment during pregnancy. A placental malaria vaccine would be an attractive, cost-effective complement to the existing control tools. Two placental malaria vaccine candidates are currently...... in Phase Ia/b clinical trials. During two workshops hosted by the European Vaccine Initiative, one in Paris in April 2014 and the other in Brussels in November 2014, the main actors in placental malaria vaccine research discussed the harmonization of clinical development plans and of the immunoassays...

  18. Experimental animal modelling for TB vaccine development

    Directory of Open Access Journals (Sweden)

    Pere-Joan Cardona

    2017-03-01

    Full Text Available Research for a novel vaccine to prevent tuberculosis is an urgent medical need. The current vaccine, BCG, has demonstrated a non-homogenous efficacy in humans, but still is the gold standard to be improved upon. In general, the main indicator for testing the potency of new candidates in animal models is the reduction of the bacillary load in the lungs at the acute phase of the infection. Usually, this reduction is similar to that induced by BCG, although in some cases a weak but significant improvement can be detected, but none of candidates are able to prevent establishment of infection. The main characteristics of several laboratory animals are reviewed, reflecting that none are able to simulate the whole characteristics of human tuberculosis. As, so far, no surrogate of protection has been found, it is important to test new candidates in several models in order to generate convincing evidence of efficacy that might be better than that of BCG in humans. It is also important to investigate the use of “in silico” and “ex vivo” models to better understand experimental data and also to try to replace, or at least reduce and refine experimental models in animals.

  19. Immunological Evaluation and Comparison of Different EV71 Vaccine Candidates

    Directory of Open Access Journals (Sweden)

    Ai-Hsiang Chou

    2012-01-01

    Full Text Available Enterovirus 71 (EV71 and coxsackievirus A16 (CVA16 are major causative agents of hand, foot, and mouth diseases (HFMDs, and EV71 is now recognized as an emerging neurotropic virus in Asia. Effective medications and/or prophylactic vaccines against HFMD are not available. The current results from mouse immunogenicity studies using in-house standardized RD cell virus neutralization assays indicate that (1 VP1 peptide (residues 211–225 formulated with Freund’s adjuvant (CFA/IFA elicited low virus neutralizing antibody response (1/32 titer; (2 recombinant virus-like particles produced from baculovirus formulated with CFA/IFA could elicit good virus neutralization titer (1/160; (3 individual recombinant EV71 antigens (VP1, VP2, and VP3 formulated with CFA/IFA, only VP1 elicited antibody response with 1/128 virus neutralization titer; and (4 the formalin-inactivated EV71 formulated in alum elicited antibodies that cross-neutralized different EV71 genotypes (1/640, but failed to neutralize CVA16. In contrast, rabbits antisera could cross-neutralize strongly against different genotypes of EV71 but weakly against CVA16, with average titers 1/6400 and 1/32, respectively. The VP1 amino acid sequence dissimilarity between CVA16 and EV71 could partially explain why mouse antibodies failed to cross-neutralize CVA16. Therefore, the best formulation for producing cost-effective HFMD vaccine is a combination of formalin-inactivated EV71 and CAV16 virions.

  20. Effect of wild-type Shigella species and attenuated Shigella vaccine candidates on small intestinal barrier function, antigen trafficking, and cytokine release.

    Directory of Open Access Journals (Sweden)

    Maria Fiorentino

    Full Text Available Bacterial dysentery due to Shigella species is a major cause of morbidity and mortality worldwide. The pathogenesis of Shigella is based on the bacteria's ability to invade and replicate within the colonic epithelium, resulting in severe intestinal inflammatory response and epithelial destruction. Although the mechanisms of pathogenesis of Shigella in the colon have been extensively studied, little is known on the effect of wild-type Shigella on the small intestine and the role of the host response in the development of the disease. Moreover, to the best of our knowledge no studies have described the effects of apically administered Shigella flexneri 2a and S. dysenteriae 1 vaccine strains on human small intestinal enterocytes. The aim of this study was to assess the coordinated functional and immunological human epithelial responses evoked by strains of Shigella and candidate vaccines on small intestinal enterocytes. To model the interactions of Shigella with the intestinal mucosa, we apically exposed monolayers of human intestinal Caco2 cells to increasing bacterial inocula. We monitored changes in paracellular permeability, examined the organization of tight-junctions and the pro-inflammatory response of epithelial cells. Shigella infection of Caco2 monolayers caused severe mucosal damage, apparent as a drastic increase in paracellular permeability and disruption of tight junctions at the cell-cell boundary. Secretion of pro-inflammatory IL-8 was independent of epithelial barrier dysfunction. Shigella vaccine strains elicited a pro-inflammatory response without affecting the intestinal barrier integrity. Our data show that wild-type Shigella infection causes a severe alteration of the barrier function of a small intestinal cell monolayer (a proxy for mucosa and might contribute (along with enterotoxins to the induction of watery diarrhea. Diarrhea may be a mechanism by which the host attempts to eliminate harmful bacteria and transport them

  1. New approaches in oral rotavirus vaccines.

    Science.gov (United States)

    Kuate Defo, Zenas; Lee, Byong

    2016-05-01

    Rotavirus is the leading cause of severe dehydrating diarrhea worldwide, and affects primarily developing nations, in large part because of the inaccessibility of vaccines and high rates of mortality present therein. At present, there exist two oral rotaviral vaccines, Rotarix™ and RotaTeq™. These vaccines are generally effective in their actions: however, associated costs often stymie their effectiveness, and they continue to be associated with a slight risk of intussusception. While different programs are being implemented worldwide to enhance vaccine distribution and monitor vaccine administration for possible intussusception in light of recent WHO recommendation, another major problem persists: that of the reduced efficacy of the existing rotaviral vaccines in developing countries over time. The development of new oral rotavirus vaccine classes - live-attenuated vaccines, virus-like particles, lactic acid bacteria-containing vaccines, combination therapy with immunoglobulins, and biodegradable polymer-encapsulated vaccines - could potentially circumvent these problems.

  2. Harnessing case isolation and ring vaccination to control Ebola.

    Directory of Open Access Journals (Sweden)

    Chad Wells

    2015-05-01

    Full Text Available As a devastating Ebola outbreak in West Africa continues, non-pharmaceutical control measures including contact tracing, quarantine, and case isolation are being implemented. In addition, public health agencies are scaling up efforts to test and deploy candidate vaccines. Given the experimental nature and limited initial supplies of vaccines, a mass vaccination campaign might not be feasible. However, ring vaccination of likely case contacts could provide an effective alternative in distributing the vaccine. To evaluate ring vaccination as a strategy for eliminating Ebola, we developed a pair approximation model of Ebola transmission, parameterized by confirmed incidence data from June 2014 to January 2015 in Liberia and Sierra Leone. Our results suggest that if a combined intervention of case isolation and ring vaccination had been initiated in the early fall of 2014, up to an additional 126 cases in Liberia and 560 cases in Sierra Leone could have been averted beyond case isolation alone. The marginal benefit of ring vaccination is predicted to be greatest in settings where there are more contacts per individual, greater clustering among individuals, when contact tracing has low efficacy or vaccination confers post-exposure protection. In such settings, ring vaccination can avert up to an additional 8% of Ebola cases. Accordingly, ring vaccination is predicted to offer a moderately beneficial supplement to ongoing non-pharmaceutical Ebola control efforts.

  3. Harnessing case isolation and ring vaccination to control Ebola.

    Science.gov (United States)

    Wells, Chad; Yamin, Dan; Ndeffo-Mbah, Martial L; Wenzel, Natasha; Gaffney, Stephen G; Townsend, Jeffrey P; Meyers, Lauren Ancel; Fallah, Mosoka; Nyenswah, Tolbert G; Altice, Frederick L; Atkins, Katherine E; Galvani, Alison P

    2015-05-01

    As a devastating Ebola outbreak in West Africa continues, non-pharmaceutical control measures including contact tracing, quarantine, and case isolation are being implemented. In addition, public health agencies are scaling up efforts to test and deploy candidate vaccines. Given the experimental nature and limited initial supplies of vaccines, a mass vaccination campaign might not be feasible. However, ring vaccination of likely case contacts could provide an effective alternative in distributing the vaccine. To evaluate ring vaccination as a strategy for eliminating Ebola, we developed a pair approximation model of Ebola transmission, parameterized by confirmed incidence data from June 2014 to January 2015 in Liberia and Sierra Leone. Our results suggest that if a combined intervention of case isolation and ring vaccination had been initiated in the early fall of 2014, up to an additional 126 cases in Liberia and 560 cases in Sierra Leone could have been averted beyond case isolation alone. The marginal benefit of ring vaccination is predicted to be greatest in settings where there are more contacts per individual, greater clustering among individuals, when contact tracing has low efficacy or vaccination confers post-exposure protection. In such settings, ring vaccination can avert up to an additional 8% of Ebola cases. Accordingly, ring vaccination is predicted to offer a moderately beneficial supplement to ongoing non-pharmaceutical Ebola control efforts.

  4. A plant-produced Pfs230 vaccine candidate blocks transmission of Plasmodium falciparum

    NARCIS (Netherlands)

    Farrance, C.E.; Rhee, A.; Jones, R.M.; Musiychuk, K.; Shamloul, M.; Sharma, S.; Mett, V.; Chichester, J.A.; Streatfield, S.J.; Roeffen, W.F.G.; Vegte-Bolmer, M.G. van de; Sauerwein, R.W.; Tsuboi, T.; Muratova, O.V.; Wu, Y.; Yusibov, V.

    2011-01-01

    Plasmodium falciparum is transmitted to a new host after completing its sexual cycle within a mosquito. Developing vaccines against the parasite sexual stages is a critical component in the fight against malaria. We are targeting multiple proteins of P. falciparum which are found only on the

  5. Hypertension Vaccine may be a boon to millions in developing world.

    Science.gov (United States)

    Bairwa, Mohan; Pilania, Manju; Gupta, Vivek; Yadav, Kapil

    2014-01-01

    Hypertension affects around 40% adults aged 25 years and more worldwide, and accounts for 7% of total disability-adjusted life-years. A simple algorithmic program is required to manage hypertension consisting of screening, life style measures, treatment and follow-up, a reliable drug supply and distribution system, and a credible health information system. Despite availability of effective antihypertensive drugs, long term treatment is still costly, tedious, and at the population level rather unsuccessful. Hypertension leaves patients and families with an avoidable heavy economic burden due to failure to control blood pressure. Health policy needs to address gross imbalance between prevention and management by increasing contribution to the preventive programs. During 21st century, the risk factors for morbidity and mortality have been changed, and researchers have started to work upon vaccines against lifestyle diseases like hypertension, diabetes etc. Researchers began experimenting with vaccines against the renin-angiotensin system to control hypertension around six decades ago. The vaccine candidates against hypertension namely ATR12181, pHAV-4Ang IIs, CYT006-AngQb, AngI-R, ATRQβ-001 have shown promising results. A candidate vaccine, CYT006-AngQb, has crossed initial phase and moved into phase 2 trials. However, more human studies in subsequent phases of trials are required to establish the safety and efficacy of anti-hypertensive vaccine. If proved safe and cost effective, a vaccine even with 50% efficacy against hypertension may protect about 90 million people from hypertension and its heavy economic burden. It can be an appropriate solution for low compliance to antihypertensive drug therapy as well as an avalanche to induce efforts on various chronic disease vaccine development programs.

  6. Biomarkers of Safety and Immune Protection for Genetically Modified Live Attenuated Leishmania Vaccines Against Visceral Leishmaniasis – Discovery and Implications

    Science.gov (United States)

    Gannavaram, Sreenivas; Dey, Ranadhir; Avishek, Kumar; Selvapandiyan, Angamuthu; Salotra, Poonam; Nakhasi, Hira L.

    2014-01-01

    Despite intense efforts there is no safe and efficacious vaccine against visceral leishmaniasis, which is fatal and endemic in many tropical countries. A major shortcoming in the vaccine development against blood-borne parasitic agents such as Leishmania is the inadequate predictive power of the early immune responses mounted in the host against the experimental vaccines. Often immune correlates derived from in-bred animal models do not yield immune markers of protection that can be readily extrapolated to humans. The limited efficacy of vaccines based on DNA, subunit, heat killed parasites has led to the realization that acquisition of durable immunity against the protozoan parasites requires a controlled infection with a live attenuated organism. Recent success of irradiated malaria parasites as a vaccine candidate further strengthens this approach to vaccination. We developed several gene deletion mutants in Leishmania donovani as potential live attenuated vaccines and reported extensively on the immunogenicity of LdCentrin1 deleted mutant in mice, hamsters, and dogs. Additional limited studies using genetically modified live attenuated Leishmania parasites as vaccine candidates have been reported. However, for the live attenuated parasite vaccines, the primary barrier against widespread use remains the absence of clear biomarkers associated with protection and safety. Recent studies in evaluation of vaccines, e.g., influenza and yellow fever vaccines, using systems biology tools demonstrated the power of such strategies in understanding the immunological mechanisms that underpin a protective phenotype. Applying similar tools in isolated human tissues such as PBMCs from healthy individuals infected with live attenuated parasites such as LdCen−/− in vitro followed by human microarray hybridization experiments will enable us to understand how early vaccine-induced gene expression profiles and the associated immune responses are coordinately regulated in normal

  7. Construct design, production, and characterization of Plasmodium falciparum 48/45 R0.6C subunit protein produced in Lactococcus lactis as candidate vaccine.

    Science.gov (United States)

    Singh, Susheel K; Roeffen, Will; Mistarz, Ulrik H; Chourasia, Bishwanath Kumar; Yang, Fen; Rand, Kasper D; Sauerwein, Robert W; Theisen, Michael

    2017-05-31

    The sexual stages of Plasmodium falciparum are responsible for the spread of the parasite in malaria endemic areas. The cysteine-rich Pfs48/45 protein, exposed on the surface of sexual stages, is one of the most advanced antigens for inclusion into a vaccine that will block transmission. However, clinical Pfs48/45 sub-unit vaccine development has been hampered by the inability to produce high yields of recombinant protein as the native structure is required for the induction of functional transmission-blocking (TB) antibodies. We have investigated a downstream purification process of a sub-unit (R0.6C) fragment representing the C-terminal 6-Cys domain of Pfs48/45 (6C) genetically fused to the R0 region (R0) of asexual stage Glutamate Rich Protein expressed in Lactococcus lactis. A series of R0.6C fusion proteins containing features, which aim to increase expression levels or to facilitate protein purification, were evaluated at small scale. None of these modifications affected the overall yield of recombinant protein. Consequently, R0.6C with a C-terminal his tag was used for upstream and downstream process development. A simple work-flow was developed consisting of batch fermentation followed by two purification steps. As such, the recombinant protein was purified to homogeneity. The composition of the final product was verified by HPLC, mass spectrometry, SDS-PAGE and Western blotting with conformation dependent antibodies against Pfs48/45. The recombinant protein induced high levels of functional TB antibodies in rats. The established production and purification process of the R0.6C fusion protein provide a strong basis for further clinical development of this candidate transmission blocking malaria vaccine.

  8. Vaccinating my way--use of alternative vaccination schedules in New York State.

    Science.gov (United States)

    Nadeau, Jessica A; Bednarczyk, Robert A; Masawi, Munyaradzi R; Meldrum, Megan D; Santilli, Loretta; Zansky, Shelley M; Blog, Debra S; Birkhead, Guthrie S; McNutt, Louise-Anne

    2015-01-01

    To identify children vaccinated following an alternative vaccine schedule using immunization information system data and determine the impact of alternative schedule use on vaccine coverage. Children born in New York State, outside New York City, between January 1, 2009 and August 14, 2011 were assessed for vaccination patterns consistent with use of an alternative schedule. Children who by 9 months of age had at least 3 vaccination visits recorded in the statewide mandatory immunization information system after 41 days of age were classified as either attempting to conform to the Centers for Disease Control and Prevention published recommended vaccination schedule or an alternative schedule. The number of vaccination visits and up-to-date status at age 9 months were compared between groups. Of the 222 628 children studied, the proportion of children following an alternative schedule was 25%. These children were significantly less likely to be up-to-date at age 9 months (15%) compared with those conforming to the routine schedule (90%, P Children following an alternative schedule on average had about 2 extra vaccine visits compared with children following a routine schedule (P children in this study appear to be intentionally deviating from the routine schedule. Intentional deviation leads to poor vaccination coverage leaving children vulnerable to infection and increasing the potential for vaccine-preventable disease outbreaks. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Vaccinomics Approach to the Identification of Candidate Protective Antigens for the Control of Tick Vector Infestations and Anaplasma phagocytophilum Infection

    Directory of Open Access Journals (Sweden)

    Marinela Contreras

    2017-08-01

    Full Text Available Anaplasma phagocytophilum is an emerging tick-borne pathogen causing human granulocytic anaplasmosis (HGA, tick-borne fever (TBF in small ruminants, and other forms of anaplasmosis in different domestic and wild animals. The main vectors of this pathogen are Ixodes tick species, particularly I. scapularis in the United States and I. ricinus in Europe. One of the main limitations for the development of effective vaccines for the prevention and control of A. phagocytophilum infection and transmission is the identification of effective tick protective antigens. The objective of this study was to apply a vaccinomics approach to I. scapularis-A. phagocytophilum interactions for the identification and characterization of candidate tick protective antigens for the control of vector infestations and A. phagocytophilum infection. The vaccinomics pipeline included the use of quantitative transcriptomics and proteomics data from uninfected and A. phagocytophilum-infected I. scapularis ticks for the selection of candidate protective antigens based on the variation in tick mRNA and protein levels in response to infection, their putative biological function, and the effect of antibodies against these proteins on tick cell apoptosis and pathogen infection. The characterization of selected candidate tick protective antigens included the identification and characterization of I. ricinus homologs, functional characterization by different methodologies including RNA interference, immunofluorescence, gene expression profiling, and artificial tick feeding on rabbit antibodies against the recombinant antigens to select the candidates for vaccination trials. The vaccinomics pipeline developed in this study resulted in the identification of two candidate tick protective antigens that could be selected for future vaccination trials. The results showed that I. scapularis lipocalin (ISCW005600 and lectin pathway inhibitor (AAY66632 and I. ricinus homologs constitute

  10. Nanotechnology Laboratory Collaborates with Army to Develop Botulism Vaccine | FNLCR

    Science.gov (United States)

    The Nanotechnology Characterization Laboratory (NCL) is collaborating with the Army to develop a candidate vaccine against botulism. Under a collaboration agreement between the National Cancer Institute and the U.S. Army Medical Research Institute of

  11. The live attenuated chimeric vaccine rWN/DEN4Δ30 is well-tolerated and immunogenic in healthy flavivirus-naïve adult volunteers.

    Science.gov (United States)

    Durbin, Anna P; Wright, Peter F; Cox, Amber; Kagucia, Wangeci; Elwood, Daniel; Henderson, Susan; Wanionek, Kimberli; Speicher, Jim; Whitehead, Stephen S; Pletnev, Alexander G

    2013-11-19

    WNV has become the leading vector-borne cause of meningoencephalitis in the United States. Although the majority of WNV infections result in asymptomatic illness, approximately 20% of infections result in West Nile fever and 1% in West Nile neuroinvasive disease (WNND), which causes encephalitis, meningitis, or flaccid paralysis. The elderly are at particular risk for WNND, with more than half the cases occurring in persons older than sixty years of age. There is no licensed treatment for WNND, nor is there any licensed vaccine for humans for the prevention of WNV infection. The Laboratory of Infectious Diseases at the National Institutes of Health has developed a recombinant live attenuated WNV vaccine based on chimerization of the wild-type WNV NY99 genome with that of the live attenuated DENV-4 candidate vaccine rDEN4Δ30. The genes encoding the prM and envelope proteins of DENV-4 were replaced with those of WNV NY99 and the resultant virus was designated rWN/DEN4Δ30. The vaccine was evaluated in healthy flavivirus-naïve adult volunteers age 18-50 years in two separate studies, both of which are reported here. The first study evaluated 10³ or 10⁴ PFU of the vaccine given as a single dose; the second study evaluated 10⁵ PFU of the vaccine given as two doses 6 months apart. The vaccine was well-tolerated and immunogenic at all three doses, inducing seroconversion to WNV NY99 in 74% (10³ PFU), 75% (10⁴ PFU), and 55% (10⁵ PFU) of subjects after a single dose. A second 10⁵ PFU dose of rWN/DEN4Δ30 given 6 months after the first dose increased the seroconversion rate 89%. Based on the encouraging results from these studies, further evaluation of the candidate vaccine in adults older than 50 years of age is planned. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Some Interesting Events from Lead-Lead Collisions in ATLAS at the LHC (individual captions in abstract)

    CERN Multimedia

    The ATLAS Experiment, ATLAS, First collisions, Splash events

    2010-01-01

    Image Captions CERN-EX-1011310 01 -- Event display of a highly asymmetric dijet event, with one jet with ET > 100 GeV and no evident recoiling jet, recorded by ATLAS in LHC lead-lead collisions. CERN-EX-1011310 02 -- Event display of a highly asymmetric dijet event, with one jet with ET > 100 GeV and no evident recoiling jet, recorded by ATLAS in LHC lead-lead collisions. CERN-EX-1011310 03 -- Event display of a highly asymmetric dijet event, with one jet with ET > 100 GeV and no evident recoiling jet, recorded by ATLAS in LHC lead-lead collisions. CERN-EX-1011310 04 -- LHC lead-lead collisions recorded by ATLAS with a candidate Z to μ+μ- decay. The two muons shown in purple are the candidates to originate from the Z decay. The transverse momenta of these two muons are 44 and 45 GeV, and the invariant mass of the dimuon system is 93 GeV. CERN-EX-1011310 05 -- LHC lead-lead collisions recorded by ATLAS with a candidate Z to μ+μ- decay. The two muons shown in red are the candidates to originate from the...

  13. Global Vaccine and Immunization Research Forum: Opportunities and challenges in vaccine discovery, development, and delivery.

    Science.gov (United States)

    Ford, Andrew Q; Touchette, Nancy; Hall, B Fenton; Hwang, Angela; Hombach, Joachim

    2016-03-18

    The World Health Organization, the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, and the Bill & Melinda Gates Foundation convened the first Global Vaccine and Immunization Research Forum (GVIRF) in March 2014. This first GVIRF aimed to track recent progress of the Global Vaccine Action Plan research and development agenda, identify opportunities and challenges, promote partnerships in vaccine research, and facilitate the inclusion of all stakeholders in vaccine research and development. Leading scientists, vaccine developers, and public health officials from around the world discussed scientific and technical challenges in vaccine development, research to improve the impact of immunization, and regulatory issues. This report summarizes the discussions and conclusions from the forum participants. Copyright © 2016. Published by Elsevier Ltd.. All rights reserved.

  14. A New Approach for Designing a Potentially Vaccine Candidate against Urinary Tract Infection by Using Protein Display on Lactobacillus

    Directory of Open Access Journals (Sweden)

    Gholamreza Goudarzi

    2015-10-01

    Full Text Available Background: The prevalence of Urinary Tract Infection (UTI is really high in the world. Escherichia coli is a major agent of UTI. One of the strategies for decreasing UTI infections is vaccine development. As the attachment is a really important stage in colonization and infection, at- tachment inhibition has an applied strategy.  FimH protein is a major factor during bacterial colonization in urinary tract and could be used as a vaccine. Thus, it was considered in this research as a candidate anti- gen.Methods: The sequences of fimH and acmA genes were used for de- signing a synthetic gene. It was cloned to pET23a expression vector and transformed  to E. coli (DE3 Origami.  To confirm the expression  of recombinant  protein,  SDS-PAGE  and western  blotting  methods  were used.  Subsequently,  recombinant  protein  was  purified.  On  the  other hand, Lactobacillus reuteri was cultured and mixed with FimH / AcmA recombinant  protein. The rate of protein localization  on lactobacillus surface was assessed using ELISA method.Results: It was showed that the recombinant protein was expressed inE. coli (DE3 Origami and purified by affinity chromatography. More- over, this protein could be localized on lactobacillus surface by 5 days. Conclusion:  In current study,  a fusion recombinant  protein was pre- pared and displayed on L. reuteri surface. This strain could be used for animal  experiment  as  a  competitor  against  Uropathogenic   E.  coli (UPEC. Using manipulated probiotics strains instead of antibiotic ther- apy could decrease the antibiotic consumption  and reduce multi-drug resistant strains.

  15. Progress and novel strategies in vaccine development and treatment of anthrax.

    Science.gov (United States)

    Chitlaru, Theodor; Altboum, Zeev; Reuveny, Shaul; Shafferman, Avigdor

    2011-01-01

    The lethal anthrax disease is caused by spores of the gram-positive Bacillus anthracis, a member of the cereus group of bacilli. Although the disease is very rare in the Western world, development of anthrax countermeasures gains increasing attention due to the potential use of B. anthracis spores as a bio-terror weapon. Protective antigen (PA), the non-toxic subunit of the bacterial secreted exotoxin, fulfills the role of recognizing a specific receptor and mediating the entry of the toxin into the host target cells. PA elicits a protective immune response and represents the basis for all current anthrax vaccines. Anti-PA neutralizing antibodies are useful correlates for protection and for vaccine efficacy evaluation. Post exposure anti-toxemic and anti-bacteremic prophylactic treatment of anthrax requires prolonged antibiotic administration. Shorter efficient postexposure treatments may require active or passive immunization, in addition to antibiotics. Although anthrax is acknowledged as a toxinogenic disease, additional factors, other than the bacterial toxin, may be involved in the virulence of B. anthracis and may be needed for the long-lasting protection conferred by PA immunization. The search for such novel factors is the focus of several high throughput genomic and proteomic studies that are already leading to identification of novel targets for therapeutics, for vaccine candidates, as well as biomarkers for detection and diagnosis. © 2010 John Wiley & Sons A/S.

  16. Targeted modifications of foot-and-mouth disease virus; towards improved vaccine candidates

    DEFF Research Database (Denmark)

    Gullberg, Maria; Polacek, Charlotta; Bøtner, Anette

    these into susceptible cells it is possible to rescue specifically altered FMDVs. We have used this approach to generate modified viruses that have particular properties; these studies can assist in the development of improved and safer vaccines to protect against FMDV. For example, we have made changes to the leader (L...

  17. Therapeutic Vaccination for HPV Induced Cervical Cancers

    Directory of Open Access Journals (Sweden)

    Joeli A. Brinkman

    2007-01-01

    Full Text Available Cervical Cancer is the second leading cause of cancer–related deaths in women worldwide and is associated with Human Papillomavirus (HPV infection, creating a unique opportunity to treat cervical cancer through anti-viral vaccination. Although a prophylactic vaccine may be available within a year, millions of women, already infected, will continue to suffer from HPV-related disease, emphasizing the need to develop therapeutic vaccination strategies. A majority of clinical trials examining therapeutic vaccination have shown limited efficacy due to examining patients with more advanced-stage cancer who tend to have decreased immune function. Current trends in clinical trials with therapeutic agents examine patients with pre-invasive lesions in order to prevent invasive cervical cancer. However, longer follow-up is necessary to correlate immune responses to lesion regression. Meanwhile, preclinical studies in this field include further exploration of peptide or protein vaccination, and the delivery of HPV antigens in DNA-based vaccines or in viral vectors. As long as pre-clinical studies continue to advance, the prospect of therapeutic vaccination to treat existing lesions seem good in the near future. Positive consequences of therapeutic vaccination would include less disfiguring treatment options and fewer instances of recurrent or progressive lesions leading to a reduction in cervical cancer incidence.

  18. Epidemic model with vaccinated age that exhibits backward bifurcation

    International Nuclear Information System (INIS)

    Yang Junyuan; Zhang Fengqin; Li Xuezhi

    2009-01-01

    Vaccination of susceptibilities is included in a transmission model for a disease that confers immunity. In this paper, interplay of vaccination strategy together with vaccine efficacy and the vaccinated age is studied. In particular, vaccine efficacy can lead to a backward bifurcation. At the same time, we also discuss an abstract formulation of the problem, and establish the well-posedness of the model.

  19. What criteria do decision makers in Thailand use to set priorities for vaccine introduction?

    Science.gov (United States)

    Pooripussarakul, Siriporn; Riewpaiboon, Arthorn; Bishai, David; Muangchana, Charung; Tantivess, Sripen

    2016-08-02

    There is a need to identify rational criteria and set priorities for vaccines. In Thailand, many licensed vaccines are being considering for introduction into the Expanded Program on Immunization; thus, the government has to make decisions about which vaccines should be adopted. This study aimed to set priorities for new vaccines and to facilitate decision analysis. We used a best-worst scaling study for rank-ordering of vaccines. The candidate vaccines were determined by a set of criteria, including burden of disease, target age group, budget impact, side effect, effectiveness, severity of disease, and cost of vaccine. The criteria were identified from a literature review and by in-depth, open-ended interviews with experts. The priority-setting model was conducted among three groups of stakeholders, including policy makers, healthcare professionals and healthcare administrators. The vaccine data were mapped and then calculated for the probability of selection. From the candidate vaccines, the probability of hepatitis B vaccine being selected by all respondents (96.67 %) was ranked first. This was followed, respectively, by pneumococcal conjugate vaccine-13 (95.09 %) and Haemophilus influenzae type b vaccine (90.87 %). The three groups of stakeholders (policy makers, healthcare professionals and healthcare administrators) showed the same ranking trends. Most severe disease, high fever rate and high disease burden showed the highest coefficients for criterion levels being selected by all respondents. This result can be implied that a vaccine which can prevent most severe disease with high disease burden and has low safety has a greater chance of being selected by respondents in this study. The priority setting of vaccines through a multiple-criteria approach could contribute to transparency and accountability in the decision-making process. This is a step forward in the development of an evidence-based approach that meets the need of developing country. The

  20. What criteria do decision makers in Thailand use to set priorities for vaccine introduction?

    Directory of Open Access Journals (Sweden)

    Siriporn Pooripussarakul

    2016-08-01

    Full Text Available Abstract Background There is a need to identify rational criteria and set priorities for vaccines. In Thailand, many licensed vaccines are being considering for introduction into the Expanded Program on Immunization; thus, the government has to make decisions about which vaccines should be adopted. This study aimed to set priorities for new vaccines and to facilitate decision analysis. Methods We used a best-worst scaling study for rank-ordering of vaccines. The candidate vaccines were determined by a set of criteria, including burden of disease, target age group, budget impact, side effect, effectiveness, severity of disease, and cost of vaccine. The criteria were identified from a literature review and by in-depth, open-ended interviews with experts. The priority-setting model was conducted among three groups of stakeholders, including policy makers, healthcare professionals and healthcare administrators. The vaccine data were mapped and then calculated for the probability of selection. Results From the candidate vaccines, the probability of hepatitis B vaccine being selected by all respondents (96.67 % was ranked first. This was followed, respectively, by pneumococcal conjugate vaccine-13 (95.09 % and Haemophilus influenzae type b vaccine (90.87 %. The three groups of stakeholders (policy makers, healthcare professionals and healthcare administrators showed the same ranking trends. Most severe disease, high fever rate and high disease burden showed the highest coefficients for criterion levels being selected by all respondents. This result can be implied that a vaccine which can prevent most severe disease with high disease burden and has low safety has a greater chance of being selected by respondents in this study. Conclusions The priority setting of vaccines through a multiple-criteria approach could contribute to transparency and accountability in the decision-making process. This is a step forward in the development of an evidence

  1. Immunogenicity of heterologous recombinant adenovirus prime-boost vaccine regimens is enhanced by circumventing vector cross-reactivity

    NARCIS (Netherlands)

    Thorner, Anna R.; Lemckert, Angelique A. C.; Goudsmit, Jaap; Lynch, Diana M.; Ewald, Bonnie A.; Denholtz, Matthew; Havenga, Menzo J. E.; Barouch, Dan H.

    2006-01-01

    The high prevalence of preexisting immunity to adenovirus serotype 5 (Ad5) in human populations has led to the development of recombinant adenovirus (rAd) vectors derived from rare Ad serotypes as vaccine candidates for human immunodeficiency virus type 1 and other pathogens. Vaccine vectors have

  2. A New Approach for Designing A Potentially Vaccine Candidate against Urinary Tract Infection by Using Protein Display on Lacto-bacillus Surface

    Directory of Open Access Journals (Sweden)

    Jalil Fallah Mehrabadi

    2013-07-01

    Full Text Available Background: The prevalence of Urinary Tract Infection (UTI is really high in the world. Escherichia coli is a major agent of UTI. One of the strategies for decreasing UTI infections is vaccine development. As the attachment is a really important stage in colonization and infection, at­tachment inhibition has an applied strategy. FimH protein is a major factor during bacterial colonization in urinary tract and could be used as a vaccine. Thus, it was considered in this research as a candidate antigen. Methods: The sequences of fimH and acmA genes were used for designing a synthetic gene. It was cloned to pET23a expression vector and transformed to E. coli (DE3 Origami. To confirm the expression of recombinant protein, SDS-PAGE and western blotting methods were used. Subsequently, recombinant protein was purified. On the other hand, Lactobacillus reuteri was cultured and mixed with FimH / AcmA recombinant protein. The rate of protein localization on lactobacillus surface was assessed using ELISA method. Results: It was showed that the recombinant protein was expressed in E. coli (DE3 Origami and purified by affinity chromatography. Moreover, this protein could be localized on lactobacillus surface by 5 days. Conclusion: In current study, a fusion recombinant protein was pre­pared and displayed on L. reuteri surface. This strain could be used for animal experiment as a competitor against Uropathogenic E. coli (UPEC. Using manipulated probiotics strains instead of antibiotic ther­apy could decrease the antibiotic consumption and reduce multi-drug resistant strains.

  3. Reintroducing resurrected species: selecting DeExtinction candidates.

    Science.gov (United States)

    Seddon, Philip J; Moehrenschlager, Axel; Ewen, John

    2014-03-01

    Technological advances have raised the controversial prospect of resurrecting extinct species. Species DeExtinction should involve more than the production of biological orphans to be scrutinized in the laboratory or zoo. If DeExtinction is to realize its stated goals of deep ecological enrichment, then resurrected animals must be translocated (i.e., released within suitable habitat). Therefore, DeExtinction is a conservation translocation issue and the selection of potential DeExtinction candidates must consider the feasibility and risks associated with reintroduction. The International Union for the Conservation of Nature (IUCN) Guidelines on Reintroductions and Other Conservation Translocations provide a framework for DeExtinction candidate selection. We translate these Guidelines into ten questions to be addressed early on in the selection process to eliminate unsuitable reintroduction candidates. We apply these questions to the thylacine, Yangtze River Dolphin, and Xerces blue butterfly. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Combined virus-like particle and fusion protein-encoding DNA vaccination of cotton rats induces protection against respiratory syncytial virus without causing vaccine-enhanced disease

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Hye Suk; Lee, Young-Tae; Kim, Ki-Hye; Park, Soojin; Kwon, Young-Man; Lee, Youri; Ko, Eun-Ju; Jung, Yu-Jin [Center for Inflammation, Immunity & Infection, Institute for Biomedical Sciences and Department of Biology, Georgia State University, Atlanta, GA (United States); Lee, Jong Seok [Center for Inflammation, Immunity & Infection, Institute for Biomedical Sciences and Department of Biology, Georgia State University, Atlanta, GA (United States); National Institute of Biological Resources, Incheon (Korea, Republic of); Kim, Yu-Jin [Center for Inflammation, Immunity & Infection, Institute for Biomedical Sciences and Department of Biology, Georgia State University, Atlanta, GA (United States); Lee, Yu-Na; Kim, Min-Chul [Center for Inflammation, Immunity & Infection, Institute for Biomedical Sciences and Department of Biology, Georgia State University, Atlanta, GA (United States); Animal and Plant Quarantine Agency, Gyeonggi-do, Gimcheon, Gyeongsangbukdo (Korea, Republic of); Cho, Minkyoung [Center for Inflammation, Immunity & Infection, Institute for Biomedical Sciences and Department of Biology, Georgia State University, Atlanta, GA (United States); Kang, Sang-Moo, E-mail: skang24@gsu.edu [Center for Inflammation, Immunity & Infection, Institute for Biomedical Sciences and Department of Biology, Georgia State University, Atlanta, GA (United States)

    2016-07-15

    A safe and effective vaccine against respiratory syncytial virus (RSV) should confer protection without causing vaccine-enhanced disease. Here, using a cotton rat model, we investigated the protective efficacy and safety of an RSV combination vaccine composed of F-encoding plasmid DNA and virus-like particles containing RSV fusion (F) and attachment (G) glycoproteins (FFG-VLP). Cotton rats with FFG-VLP vaccination controlled lung viral replication below the detection limit, and effectively induced neutralizing activity and antibody-secreting cell responses. In comparison with formalin inactivated RSV (FI-RSV) causing severe RSV disease after challenge, FFG-VLP vaccination did not cause weight loss, airway hyper-responsiveness, IL-4 cytokines, histopathology, and infiltrates of proinflammatory cells such as eosinophils. FFG-VLP was even more effective in preventing RSV-induced pulmonary inflammation than live RSV infections. This study provides evidence that FFG-VLP can be developed into a safe and effective RSV vaccine candidate. - Highlights: • Combined RSV FFG VLP vaccine is effective in inducing F specific responses. • FFG VLP vaccine confers RSV neutralizing activity and viral control in cotton rats. • Cotton rats with RSV FFG VLP vaccination do not show vaccine-enhanced disease. • Cotton rats with FFG VLP vaccine induce F specific antibody secreting cell responses. • Cotton rats with FFG VLP do not induce lung cellular infiltrates and Th2 cytokine.

  5. Combined virus-like particle and fusion protein-encoding DNA vaccination of cotton rats induces protection against respiratory syncytial virus without causing vaccine-enhanced disease

    International Nuclear Information System (INIS)

    Hwang, Hye Suk; Lee, Young-Tae; Kim, Ki-Hye; Park, Soojin; Kwon, Young-Man; Lee, Youri; Ko, Eun-Ju; Jung, Yu-Jin; Lee, Jong Seok; Kim, Yu-Jin; Lee, Yu-Na; Kim, Min-Chul; Cho, Minkyoung; Kang, Sang-Moo

    2016-01-01

    A safe and effective vaccine against respiratory syncytial virus (RSV) should confer protection without causing vaccine-enhanced disease. Here, using a cotton rat model, we investigated the protective efficacy and safety of an RSV combination vaccine composed of F-encoding plasmid DNA and virus-like particles containing RSV fusion (F) and attachment (G) glycoproteins (FFG-VLP). Cotton rats with FFG-VLP vaccination controlled lung viral replication below the detection limit, and effectively induced neutralizing activity and antibody-secreting cell responses. In comparison with formalin inactivated RSV (FI-RSV) causing severe RSV disease after challenge, FFG-VLP vaccination did not cause weight loss, airway hyper-responsiveness, IL-4 cytokines, histopathology, and infiltrates of proinflammatory cells such as eosinophils. FFG-VLP was even more effective in preventing RSV-induced pulmonary inflammation than live RSV infections. This study provides evidence that FFG-VLP can be developed into a safe and effective RSV vaccine candidate. - Highlights: • Combined RSV FFG VLP vaccine is effective in inducing F specific responses. • FFG VLP vaccine confers RSV neutralizing activity and viral control in cotton rats. • Cotton rats with RSV FFG VLP vaccination do not show vaccine-enhanced disease. • Cotton rats with FFG VLP vaccine induce F specific antibody secreting cell responses. • Cotton rats with FFG VLP do not induce lung cellular infiltrates and Th2 cytokine.

  6. In silico analysis for identifying potential vaccine candidates against Staphylococcus aureus

    OpenAIRE

    Delfani, Somayeh; Imani Fooladi, Abbas Ali; Mobarez, Ashraf Mohabati; Emaneini, Mohammad; Amani, Jafar; Sedighian, Hamid

    2015-01-01

    Purpose Staphylococcus aureus is one of the most important causes of nosocomial and community-acquired infections. The increasing incidence of multiple antibiotic-resistant S. aureus strains and the emergence of vancomycin resistant S. aureus strains have placed renewed interest on alternative means of prevention and control of infection. S. aureus produces a variety of virulence factors, so a multi-subunit vaccine will be more successful for preventing S. aureus infections than a mono-subuni...

  7. [Economic evaluation for the prevention of cervical cancer by vaccination--from perspective of health insurance society and industry].

    Science.gov (United States)

    Kawabayashi, Yukari; Furuno, Makoto; Uchida, Marina; Kawana, Takashi

    2013-04-01

    The aim of this study is to estimate the budget impact in a health insurance society and an industry of promoting decision-making for endowing grants for vaccination as prophylaxis against cervical cancer (CC) by the health insurance society for employees. The target population was Japanese female employees aged 20 to 34 and partners and daughters of male employees working for an overseas IT industry. By using a prevalence-based model, the author estimated expected costs in non-vaccination and vaccination scenarios and evaluated the 10-year financial impact on the industry after vaccination by employing a cost-benefit analysis. The incidence of CC in a target group was derived from the actual number of patients with CC in addition to data from JMDC's receipt database and estimated by a Bayesian method. The epidemiological parameters such as mortality rate, screening rate, detailed exam rate and detailed exam consultation rate were taken from epidemiology statistics and published articles available in Japan. Healthcare costs for cancer treatment, screening, detailed exam and vaccination estimated based on medical fee points were input into the model, 'but the analysis did not consider side effect-related costs. In addition, productivity costs for mortality in employees and their families due to CC, estimated by the national employee's statistics, were also input into the model. An annual discount was unconsidered. From the perspective of the healthcare insurance society, expenditure of approximately 129 million yen in the non-vaccination scenario was expected for ten years, but healthcare-related costs were saved by expenditure of approximately 73 million yen with 100% of employees and their families being vaccinated at expenses of approximately 55 million yen. The insurance society lost approximately 1.8 million yen in total if subsidy for vaccination was set at ten thousand yen. In the case of a 100% vaccination rate, the company can save losses in productivity of

  8. Rational design of human metapneumovirus live attenuated vaccine candidates by inhibiting viral mRNA cap methyltransferase.

    Science.gov (United States)

    Zhang, Yu; Wei, Yongwei; Zhang, Xiaodong; Cai, Hui; Niewiesk, Stefan; Li, Jianrong

    2014-10-01

    The paramyxoviruses human respiratory syncytial virus (hRSV), human metapneumovirus (hMPV), and human parainfluenza virus type 3 (hPIV3) are responsible for the majority of pediatric respiratory diseases and inflict significant economic loss, health care costs, and emotional burdens. Despite major efforts, there are no vaccines available for these viruses. The conserved region VI (CR VI) of the large (L) polymerase proteins of paramyxoviruses catalyzes methyltransferase (MTase) activities that typically methylate viral mRNAs at positions guanine N-7 (G-N-7) and ribose 2'-O. In this study, we generated a panel of recombinant hMPVs carrying mutations in the S-adenosylmethionine (SAM) binding site in CR VI of L protein. These recombinant viruses were specifically defective in ribose 2'-O methylation but not G-N-7 methylation and were genetically stable and highly attenuated in cell culture and viral replication in the upper and lower respiratory tracts of cotton rats. Importantly, vaccination of cotton rats with these recombinant hMPVs (rhMPVs) with defective MTases triggered a high level of neutralizing antibody, and the rats were completely protected from challenge with wild-type rhMPV. Collectively, our results indicate that (i) amino acid residues in the SAM binding site in the hMPV L protein are essential for 2'-O methylation and (ii) inhibition of mRNA cap MTase can serve as a novel target to rationally design live attenuated vaccines for hMPV and perhaps other paramyxoviruses, such as hRSV and hPIV3. Human paramyxoviruses, including hRSV, hMPV, and hPIV3, cause the majority of acute upper and lower respiratory tract infections in humans, particularly in infants, children, the elderly, and immunocompromised individuals. Currently, there is no licensed vaccine available. A formalin-inactivated vaccine is not suitable for these viruses because it causes enhanced lung damage upon reinfection with the same virus. A live attenuated vaccine is the most promising

  9. A single-dose live-attenuated vaccine prevents Zika virus pregnancy transmission and testis damage.

    Science.gov (United States)

    Shan, Chao; Muruato, Antonio E; Jagger, Brett W; Richner, Justin; Nunes, Bruno T D; Medeiros, Daniele B A; Xie, Xuping; Nunes, Jannyce G C; Morabito, Kaitlyn M; Kong, Wing-Pui; Pierson, Theodore C; Barrett, Alan D; Weaver, Scott C; Rossi, Shannan L; Vasconcelos, Pedro F C; Graham, Barney S; Diamond, Michael S; Shi, Pei-Yong

    2017-09-22

    Zika virus infection during pregnancy can cause congenital abnormities or fetal demise. The persistence of Zika virus in the male reproductive system poses a risk of sexual transmission. Here we demonstrate that live-attenuated Zika virus vaccine candidates containing deletions in the 3' untranslated region of the Zika virus genome (ZIKV-3'UTR-LAV) prevent viral transmission during pregnancy and testis damage in mice, as well as infection of nonhuman primates. After a single-dose vaccination, pregnant mice challenged with Zika virus at embryonic day 6 and evaluated at embryonic day 13 show markedly diminished levels of viral RNA in maternal, placental, and fetal tissues. Vaccinated male mice challenged with Zika virus were protected against testis infection, injury, and oligospermia. A single immunization of rhesus macaques elicited a rapid and robust antibody response, conferring complete protection upon challenge. Furthermore, the ZIKV-3'UTR-LAV vaccine candidates have a desirable safety profile. These results suggest that further development of ZIKV-3'UTR-LAV is warranted for humans.Zika virus infection can result in congenital disorders and cause disease in adults, and there is currently no approved vaccine. Here Shan et al. show that a single dose of a live-attenuated Zika vaccine prevents infection, testis damage and transmission to the fetus during pregnancy in different animal models.

  10. [Animal experimentation in the discovery and production of veterinary vaccines].

    Science.gov (United States)

    Audonnet, J Ch; Lechenet, J; Verschuere, B

    2007-08-01

    Veterinary vaccine research, development and production facilities must aim to improve animal welfare, respond to public concerns and meet regulatory requirements, while at the same time fulfilling their objective of producing evermore effective and safer vaccines. The use of animal experimentation for the development of new veterinary vaccines is inevitable, as no in vitro model can predict a candidate vaccine's ability to induce protection in the target species. Against the backdrop of ethical and regulatory constraints, constant progress is being made in creating the best possible conditions for animal experimentation. Keeping up to date with the constant changes in the field of animal ethics requires a particular effort on the part of the pharmaceutical industry, which must make careful changes to product registration documentation in accordance with each new development.

  11. The Duration of Immunity to an Inactivated Adjuvanted Canine Parvovirus Vaccine. A 52 and 64 Week Postvaccination Challenge Study

    OpenAIRE

    Povey, R. C.; Carman, P. S.; Ewert, E.

    1983-01-01

    Dogs were successfully isolated for a period of either 52 or 64 weeks following vaccination with an inactivated, adjuvanted canine parvovirus-2 vaccine. Antibody persisted in all ten vaccinated dogs, although in one case by 52 weeks postvaccination only virus neutralizing antibody, and not hemagglutination-inhibiting antibody, could be detected. Sentinel unvaccinated dogs housed alongside the vaccinated dogs throughout the study remained free of canine parvovirus-2 antibody until challenged. ...

  12. Zika virus-like particle (VLP) based vaccine

    Science.gov (United States)

    Boigard, Hélène; Alimova, Alexandra; Martin, George R.; Katz, Al; Gottlieb, Paul

    2017-01-01

    The newly emerged mosquito-borne Zika virus poses a major public challenge due to its ability to cause significant birth defects and neurological disorders. The impact of sexual transmission is unclear but raises further concerns about virus dissemination. No specific treatment or vaccine is currently available, thus the development of a safe and effective vaccine is paramount. Here we describe a novel strategy to assemble Zika virus-like particles (VLPs) by co-expressing the structural (CprME) and non-structural (NS2B/NS3) proteins, and demonstrate their effectiveness as vaccines. VLPs are produced in a suspension culture of mammalian cells and self-assembled into particles closely resembling Zika viruses as shown by electron microscopy studies. We tested various VLP vaccines and compared them to analogous compositions of an inactivated Zika virus (In-ZIKV) used as a reference. VLP immunizations elicited high titers of antibodies, as did the In-ZIKV controls. However, in mice the VLP vaccine stimulated significantly higher virus neutralizing antibody titers than comparable formulations of the In-ZIKV vaccine. The serum neutralizing activity elicited by the VLP vaccine was enhanced using a higher VLP dose and with the addition of an adjuvant, reaching neutralizing titers greater than those detected in the serum of a patient who recovered from a Zika infection in Brazil in 2015. Discrepancies in neutralization levels between the VLP vaccine and the In-ZIKV suggest that chemical inactivation has deleterious effects on neutralizing epitopes within the E protein. This along with the inability of a VLP vaccine to cause infection makes it a preferable candidate for vaccine development. PMID:28481898

  13. Immunological evaluation of lipopeptide group A streptococcus (GAS vaccine: structure-activity relationship.

    Directory of Open Access Journals (Sweden)

    Mehfuz Zaman

    Full Text Available Streptococcus pyogenes (group A streptococcus, GAS is a Gram-positive bacterial pathogen responsible for a wide variety of diseases. To date, GAS vaccine development has focused primarily on the M-protein. The M-protein is highly variable at the amino (N-terminus (determining serotype but is conserved at the carboxyl (C-terminus. Previously a 29 amino acid peptide (named J14 from the conserved region of the M-protein was identified as a potential vaccine candidate. J14 was capable of eliciting protective antibodies that recognized many GAS serotypes when co-administered with immuno-stimulants. This minimal epitope however showed no immunogenicity when administered alone. In an attempt overcome this immunological non-responsiveness, we developed a self-adjuvanting vaccine candidate composed of three components: the B-cell epitope (J14, a universal helper T-cell epitope (P25 and a lipid moiety consisting of lipoamino acids (Laas which target Toll-like receptor 2 (TLR2. Immunological evaluation in B10.BR (H-2k mice demonstrated that the epitope attachment to the point of lipid moiety, and the length of the Laa alkyl chain have a profound effect on vaccine immunogenicity after intranasal administration. It was demonstrated that a vaccine featuring C-terminal lipid moiety containing alkyl chains of 16 carbons, with P25 located at the N-terminus, and J14 attached to the side chain of a central lysine residue was capable of inducing optimal antibody response. These findings have considerable relevance to the development of a broad spectrum J14-based GAS vaccine and in particular provided a rational basis for peptide vaccine design based on this self-adjuvanting lipopeptide technology.

  14. Structural Simulation of MHC-peptide Interactions using T-cell Epitope in Iron-acquisition Protein of N. meningitides for Vaccine Design

    Directory of Open Access Journals (Sweden)

    Namrata Mishra

    2010-12-01

    Full Text Available The present work uses a structural simulation approach to identify the potential target vaccine candidates or T cell epitopes (antigenic region that can activate T cell response in two iron acquisition proteins from Neisseria. An iron regulated outer membrane protein frpB: extracellular, [NMB1988], and a Major ferric Iron-binding protein fbpA: periplasmic, [NMB0634] critical for the survival of the pathogen in the host were used. Ten novel promiscuous epitopes from the two iron acquisition proteins were identified using bioinformatics interface. Of these epitopes, 630VQKAVGSIL638 present on frpB with high binding affinity for allele HLA*DR1 was identified with an anchor position at P2, an aliphatic residue at P4 and glycine at P6 making it thereby a potential quality choice for linking peptide-loaded MHC dynamics to T-cell activation and vaccine constructs. The feasibility and structural binding of predicted peptide to the respective HLA allele was investigated by molecular modeling and template-based structural simulation. The conformational properties of the linear peptide were investigated by molecular dynamics using GROMOS96 package and Swiss PDB viewer.

  15. Vaccines for emerging infectious diseases: Lessons from MERS coronavirus and Zika virus.

    Science.gov (United States)

    Maslow, Joel N

    2017-12-02

    The past decade and a half has been characterized by numerous emerging infectious diseases. With each new threat, there has been a call for rapid vaccine development. Pathogens such as the Middle East Respiratory Syndrome coronavirus (MERS-CoV) and the Zika virus represent either new viral entities or viruses emergent in new geographic locales and characterized by novel complications. Both serve as paradigms for the global spread that can accompany new pathogens. In this paper, we review the epidemiology and pathogenesis of MERS-CoV and Zika virus with respect to vaccine development. The challenges in vaccine development and the approach to clinical trial design to test vaccine candidates for disease entities with a changing epidemiology are discussed.

  16. Schistosoma mansoni: parasitology and immunology of baboons vaccinated with irradiated cryopreserved schistosomula

    Energy Technology Data Exchange (ETDEWEB)

    Damian, R T; Powell, M R; Roberts, M L [Georgia Univ., Athens (USA). Dept. of Zoology; Clark, J D [Georgia Univ., Athens (USA). Lab. Animal Medicine; Stirewalt, M A; Lewis, F A [Biomedical Research Inst., Rockville, MD (USA)

    1985-06-01

    Young baboons (Papio cynocephalus) were vaccinated with ..gamma..-irradiated (500 Gy) cryopreserved Puerto Rican strain schistosomula of S. mansoni. Protection against heterologous, normal Kenyan Strain S. mansoni challenge infection was erratic and partial; and two putative correlates of immunity, reduced worm fecundity and change in worm location (anterior shift) were not observed. However, immunization of baboons with this vaccine resulted in a stimulated immune system. Both cellular and humoral anamnesis were demonstrable in vaccinated-challenged baboons. Schistosome infection-associated IgM hypergammaglobulinemia was also greatly reduced in vaccinated-challenged baboons. However IgG antibodies to adult, egg, and cercarial antigens were increased after challenge infection in preimmunized baboons. Vaccination appears to have resulted in a redirection of the immune system into anti-parasite channels, but this more specific immune response was insufficient to confer good protection against challenge infection in this experiment. The dampening effect of the vaccine on the hypergammaglobulinemia of schistosomiasis is another candidate for a possible ''anti-pathogenesis'' effect of irradiated schistosome larval vaccines.

  17. Pre-clinical efficacy and safety of experimental vaccines based on non-replicating vaccinia vectors against yellow fever.

    Directory of Open Access Journals (Sweden)

    Birgit Schäfer

    Full Text Available BACKGROUND: Currently existing yellow fever (YF vaccines are based on the live attenuated yellow fever virus 17D strain (YFV-17D. Although, a good safety profile was historically attributed to the 17D vaccine, serious adverse events have been reported, making the development of a safer, more modern vaccine desirable. METHODOLOGY/PRINCIPAL FINDINGS: A gene encoding the precursor of the membrane and envelope (prME protein of the YFV-17D strain was inserted into the non-replicating modified vaccinia virus Ankara and into the D4R-defective vaccinia virus. Candidate vaccines based on the recombinant vaccinia viruses were assessed for immunogenicity and protection in a mouse model and compared to the commercial YFV-17D vaccine. The recombinant live vaccines induced γ-interferon-secreting CD4- and functionally active CD8-T cells, and conferred full protection against lethal challenge already after a single low immunization dose of 10(5 TCID(50. Surprisingly, pre-existing immunity against wild-type vaccinia virus did not negatively influence protection. Unlike the classical 17D vaccine, the vaccinia virus-based vaccines did not cause mortality following intracerebral administration in mice, demonstrating better safety profiles. CONCLUSIONS/SIGNIFICANCE: The non-replicating recombinant YF candidate live vaccines induced a broad immune response after single dose administration, were effective even in the presence of a pre-existing immunity against vaccinia virus and demonstrated an excellent safety profile in mice.

  18. Pre-Clinical Efficacy and Safety of Experimental Vaccines Based on Non-Replicating Vaccinia Vectors against Yellow Fever

    Science.gov (United States)

    Schäfer, Birgit; Holzer, Georg W.; Joachimsthaler, Alexandra; Coulibaly, Sogue; Schwendinger, Michael; Crowe, Brian A.; Kreil, Thomas R.; Barrett, P. Noel; Falkner, Falko G.

    2011-01-01

    Background Currently existing yellow fever (YF) vaccines are based on the live attenuated yellow fever virus 17D strain (YFV-17D). Although, a good safety profile was historically attributed to the 17D vaccine, serious adverse events have been reported, making the development of a safer, more modern vaccine desirable. Methodology/Principal Findings A gene encoding the precursor of the membrane and envelope (prME) protein of the YFV-17D strain was inserted into the non-replicating modified vaccinia virus Ankara and into the D4R-defective vaccinia virus. Candidate vaccines based on the recombinant vaccinia viruses were assessed for immunogenicity and protection in a mouse model and compared to the commercial YFV-17D vaccine. The recombinant live vaccines induced γ-interferon-secreting CD4- and functionally active CD8-T cells, and conferred full protection against lethal challenge already after a single low immunization dose of 105 TCID50. Surprisingly, pre-existing immunity against wild-type vaccinia virus did not negatively influence protection. Unlike the classical 17D vaccine, the vaccinia virus-based vaccines did not cause mortality following intracerebral administration in mice, demonstrating better safety profiles. Conclusions/Significance The non-replicating recombinant YF candidate live vaccines induced a broad immune response after single dose administration, were effective even in the presence of a pre-existing immunity against vaccinia virus and demonstrated an excellent safety profile in mice. PMID:21931732

  19. Planck early results. IX. XMM-Newton follow-up for validation of Planck cluster candidates

    DEFF Research Database (Denmark)

    Poutanen, T.; Natoli, P.; Polenta, G.

    2011-01-01

    We present the XMM-Newton follow-up for confirmation of Planck cluster candidates. Twenty-five candidates have been observed to date using snapshot (∼10 ks) exposures, ten as part of a pilot programme to sample a low range of signal-to-noise ratios (4

  20. Time will tell: community acceptability of HIV vaccine research before and after the “Step Study” vaccine discontinuation

    Directory of Open Access Journals (Sweden)

    Paula M Frew

    2010-09-01

    Full Text Available Paula M Frew1,2,3,4, Mark J Mulligan1,2,3, Su-I Hou5, Kayshin Chan3, Carlos del Rio1,2,3,61Department of Medicine, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia, USA; 2Emory Center for AIDS Research, Atlanta, Georgia, USA; 3The Hope Clinic of the Emory Vaccine Center, Decatur, Georgia, USA; 4Department of Behavioral Sciences and Health Education, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA; 5Department of Health Promotion and Behavior, College of Public Health, University of Georgia, Athens, Georgia, USA; 6Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USAObjective: This study examines whether men-who-have-sex-with-men (MSM and transgender (TG persons’ attitudes, beliefs, and risk perceptions toward human immunodeficiency virus (HIV vaccine research have been altered as a result of the negative findings from a phase 2B HIV vaccine study.Design: We conducted a cross-sectional survey among MSM and TG persons (N = 176 recruited from community settings in Atlanta from 2007 to 2008. The first group was recruited during an active phase 2B HIV vaccine trial in which a candidate vaccine was being evaluated (the “Step Study”, and the second group was recruited after product futility was widely reported in the media.Methods: Descriptive statistics, t tests, and chi-square tests were conducted to ascertain differences between the groups, and ordinal logistic regressions examined the influences of the above-mentioned factors on a critical outcome, future HIV vaccine study participation. The ordinal regression outcomes evaluated the influences on disinclination, neutrality, and inclination to study participation.Results: Behavioral outcomes such as future recruitment, event attendance, study promotion, and community mobilization did not reveal any differences in participants’ intentions between the groups. However, we observed

  1. European Pharmacopoeia biological reference preparation for poliomyelitis vaccine (inactivated): collaborative study for the establishment of batch No. 3.

    Science.gov (United States)

    Martin, J; Daas, A; Milne, C

    2016-01-01

    Inactivated poliomyelitis vaccines are an important part of the World Health Organization (WHO) control strategy to eradicate poliomyelitis. Requirements for the quality control of poliomyelitis vaccines (inactivated) include the use of an in vitro D antigen quantification assay for potency determination on the final lot as outlined in the European Pharmacopoeia (Ph. Eur.) monograph 0214. Performance of this assay requires a reference preparation calibrated in International Units (IU). A Ph. Eur. biological reference preparation (BRP) for poliomyelitis vaccine (inactivated) calibrated in IU has been established for this purpose. Due to the dwindling stocks of batch 2 of the BRP a collaborative study was run as part of the European Directorate for the Quality of Medicines & HealthCare (EDQM) Biological Standardisation Programme to establish BRP batch 3 (BRP3). Twelve laboratories including Official Medicines Control Laboratories (OMCLs) and manufacturers participated. The candidate BRP3 (cBRP3) was from the same source and had the same characteristics as BRP batch 2 (BRP2). During the study the candidate was calibrated against the 3 rd International Standard for inactivated poliomyelitis vaccine using in-house D antigen ELISA assays in line with the Ph. Eur. monograph 0214. The candidate was also compared to BRP2 to evaluate the continuity. Based on the results of the study, values of 320 DU/mL, 78 DU/mL and 288 DU/mL (D antigen units/mL) (IU) for poliovirus type 1, 2 and 3 respectively were assigned to the candidate. In June 2016, the Ph. Eur. Commission adopted the material as Ph. Eur. BRP for poliomyelitis vaccine (inactivated) batch 3.

  2. Valuing vaccination.

    Science.gov (United States)

    Bärnighausen, Till; Bloom, David E; Cafiero-Fonseca, Elizabeth T; O'Brien, Jennifer Carroll

    2014-08-26

    Vaccination has led to remarkable health gains over the last century. However, large coverage gaps remain, which will require significant financial resources and political will to address. In recent years, a compelling line of inquiry has established the economic benefits of health, at both the individual and aggregate levels. Most existing economic evaluations of particular health interventions fail to account for this new research, leading to potentially sizable undervaluation of those interventions. In line with this new research, we set forth a framework for conceptualizing the full benefits of vaccination, including avoided medical care costs, outcome-related productivity gains, behavior-related productivity gains, community health externalities, community economic externalities, and the value of risk reduction and pure health gains. We also review literature highlighting the magnitude of these sources of benefit for different vaccinations. Finally, we outline the steps that need to be taken to implement a broad-approach economic evaluation and discuss the implications of this work for research, policy, and resource allocation for vaccine development and delivery.

  3. An evaluation of the emerging vaccines and immunotherapy against staphylococcal pneumonia in children

    Directory of Open Access Journals (Sweden)

    Rubens Craig

    2011-04-01

    Full Text Available Abstract Background Staphylococcus aureus is a commensal of human skin and nares. It is also one of the leading nosocomial pathogens in both developed and developing countries and is responsible for a wide range of life threatening infections, especially in patients who are immunocompromised, post-surgery, undergoing haemodialysis and those who are treated with catheters and ventilators. Over the past two decades, the incidence of nosocomial staphylococcal infections has increased dramatically. Currently there are at least seven vaccine and immunotherapy candidates against S. aureus in the developmental phase targeting both active and passive immunization. Methods We used a modified CHNRI methodology for setting priorities in health research investments. This was done in two stages. In Stage I, we systematically reviewed the literature related to emerging vaccines against Staphylococcus aureus relevant to several criteria of interest: answerability; cost of development, production and implementation; efficacy and effectiveness; deliverability, affordability and sustainability; maximum potential impact on disease burden reduction; acceptability to the end users and health workers; and effect on equity. In Stage II, we conducted an expert opinion exercise by inviting 20 experts (leading basic scientists, international public health researchers, international policy makers and representatives of pharmaceutical companies to participate. The policy makers and industry representatives accepted our invitation on the condition of anonymity, due to sensitive nature of their involvement in such exercises. They answered questions from CHNRI framework and their “collective optimism” towards each criterion was documented on a scale from 0 to 100%. Results The panel of experts expressed low levels of optimism (score around or below 50% on the criteria of answerability, efficacy, maximum disease burden reduction potential, low cost of production, low cost

  4. An evaluation of the emerging vaccines and immunotherapy against staphylococcal pneumonia in children.

    Science.gov (United States)

    Huda, Tanvir; Nair, Harish; Theodoratou, Evropi; Zgaga, Lina; Fattom, Ali; El Arifeen, Shams; Rubens, Craig; Campbell, Harry; Rudan, Igor

    2011-04-13

    Staphylococcus aureus is a commensal of human skin and nares. It is also one of the leading nosocomial pathogens in both developed and developing countries and is responsible for a wide range of life threatening infections, especially in patients who are immunocompromised, post-surgery, undergoing haemodialysis and those who are treated with catheters and ventilators. Over the past two decades, the incidence of nosocomial staphylococcal infections has increased dramatically. Currently there are at least seven vaccine and immunotherapy candidates against S. aureus in the developmental phase targeting both active and passive immunization. We used a modified CHNRI methodology for setting priorities in health research investments. This was done in two stages. In Stage I, we systematically reviewed the literature related to emerging vaccines against Staphylococcus aureus relevant to several criteria of interest: answerability; cost of development, production and implementation; efficacy and effectiveness; deliverability, affordability and sustainability; maximum potential impact on disease burden reduction; acceptability to the end users and health workers; and effect on equity. In Stage II, we conducted an expert opinion exercise by inviting 20 experts (leading basic scientists, international public health researchers, international policy makers and representatives of pharmaceutical companies) to participate. The policy makers and industry representatives accepted our invitation on the condition of anonymity, due to sensitive nature of their involvement in such exercises. They answered questions from CHNRI framework and their "collective optimism" towards each criterion was documented on a scale from 0 to 100%. The panel of experts expressed low levels of optimism (score around or below 50%) on the criteria of answerability, efficacy, maximum disease burden reduction potential, low cost of production, low cost of implementation and affordability; moderate levels of

  5. Vaccinating high-risk children with the intranasal live-attenuated influenza vaccine: the Quebec experience.

    Science.gov (United States)

    Quach, Caroline

    2014-12-01

    Given the burden of illness associated with influenza, vaccination is recommended for individuals at high risk of complications. The live-attenuated influenza vaccine (LAIV) is administered by intranasal spray, thus directly stimulating mucosal immunity. In this review, we aimed to provide evidence for its efficacy and safety in different paediatric populations. We also share the Quebec experience of LAIV use through a publicly funded vaccination program for children with chronic, high-risk conditions. from randomized controlled trials in healthy children and in asthmatics have demonstrated superior efficacy of LAIV over the injectable vaccine (IIV). LAIV is well tolerated: its administration is associated with runny nose and nasal congestion, but not with asthma exacerbations and is well tolerated in children with cystic fibrosis, when compared to IIV. The vaccine is well accepted by children and parents and can easily be part of vaccination clinics in paediatric tertiary care centres targeting children with chronic, high-risk conditions, not leading to immunosuppression. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Development of an Aotus nancymaae Model for Shigella Vaccine Immunogenicity and Efficacy Studies

    OpenAIRE

    Gregory, Michael; Kaminski, Robert W.; Lugo-Roman, Luis A.; Galvez Carrillo, Hugo; Tilley, Drake Hamilton; Baldeviano, Christian; Simons, Mark P.; Reynolds, Nathanael D.; Ranallo, Ryan T.; Suvarnapunya, Akamol E.; Venkatesan, Malabi M.; Oaks, Edwin V.

    2014-01-01

    Several animal models exist to evaluate the immunogenicity and protective efficacy of candidate Shigella vaccines. The two most widely used nonprimate models for vaccine development include a murine pulmonary challenge model and a guinea pig keratoconjunctivitis model. Nonhuman primate models exhibit clinical features and gross and microscopic colonic lesions that mimic those induced in human shigellosis. Challenge models for enterotoxigenic Escherichia coli (ETEC) and Campylobacter spp. have...

  7. Vaccines, our shared responsibility.

    Science.gov (United States)

    Pagliusi, Sonia; Jain, Rishabh; Suri, Rajinder Kumar

    2015-05-05

    The Developing Countries Vaccine Manufacturers' Network (DCVMN) held its fifteenth annual meeting from October 27-29, 2014, New Delhi, India. The DCVMN, together with the co-organizing institution Panacea Biotec, welcomed over 240 delegates representing high-profile governmental and nongovernmental global health organizations from 36 countries. Over the three-day meeting, attendees exchanged information about their efforts to achieve their shared goal of preventing death and disability from known and emerging infectious diseases. Special praise was extended to all stakeholders involved in the success of polio eradication in South East Asia and highlighted challenges in vaccine supply for measles-rubella immunization over the coming decades. Innovative vaccines and vaccine delivery technologies indicated creative solutions for achieving global immunization goals. Discussions were focused on three major themes including regulatory challenges for developing countries that may be overcome with better communication; global collaborations and partnerships for leveraging investments and enable uninterrupted supply of affordable and suitable vaccines; and leading innovation in vaccines difficult to develop, such as dengue, Chikungunya, typhoid-conjugated and EV71, and needle-free technologies that may speed up vaccine delivery. Moving further into the Decade of Vaccines, participants renewed their commitment to shared responsibility toward a world free of vaccine-preventable diseases. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Critical dynamics in population vaccinating behavior.

    Science.gov (United States)

    Pananos, A Demetri; Bury, Thomas M; Wang, Clara; Schonfeld, Justin; Mohanty, Sharada P; Nyhan, Brendan; Salathé, Marcel; Bauch, Chris T

    2017-12-26

    Vaccine refusal can lead to renewed outbreaks of previously eliminated diseases and even delay global eradication. Vaccinating decisions exemplify a complex, coupled system where vaccinating behavior and disease dynamics influence one another. Such systems often exhibit critical phenomena-special dynamics close to a tipping point leading to a new dynamical regime. For instance, critical slowing down (declining rate of recovery from small perturbations) may emerge as a tipping point is approached. Here, we collected and geocoded tweets about measles-mumps-rubella vaccine and classified their sentiment using machine-learning algorithms. We also extracted data on measles-related Google searches. We find critical slowing down in the data at the level of California and the United States in the years before and after the 2014-2015 Disneyland, California measles outbreak. Critical slowing down starts growing appreciably several years before the Disneyland outbreak as vaccine uptake declines and the population approaches the tipping point. However, due to the adaptive nature of coupled behavior-disease systems, the population responds to the outbreak by moving away from the tipping point, causing "critical speeding up" whereby resilience to perturbations increases. A mathematical model of measles transmission and vaccine sentiment predicts the same qualitative patterns in the neighborhood of a tipping point to greatly reduced vaccine uptake and large epidemics. These results support the hypothesis that population vaccinating behavior near the disease elimination threshold is a critical phenomenon. Developing new analytical tools to detect these patterns in digital social data might help us identify populations at heightened risk of widespread vaccine refusal. Copyright © 2017 the Author(s). Published by PNAS.

  9. Application of a scalable plant transient gene expression platform for malaria vaccine development

    Directory of Open Access Journals (Sweden)

    Holger eSpiegel

    2015-12-01

    Full Text Available Despite decades of intensive research efforts there is currently no vaccine that provides sustained sterile immunity against malaria. In this context, a large number of targets from the different stages of the Plasmodium falciparum life cycle have been evaluated as vaccine candidates. None of these candidates has fulfilled expectations, and as long as we lack a single target that induces strain-transcending protective immune responses, combining key antigens from different life cycle stages seems to be the most promising route towards the development of efficacious malaria vaccines. After the identification of potential targets using approaches such as omics-based technology and reverse immunology, the rapid expression, purification and characterization of these proteins, as well as the generation and analysis of fusion constructs combining different promising antigens or antigen domains before committing to expensive and time consuming clinical development, represents one of the bottlenecks in the vaccine development pipeline. The production of recombinant proteins by transient gene expression in plants is a robust and versatile alternative to cell-based microbial and eukaryotic production platforms. The transfection of plant tissues and/or whole plants using Agrobacterium tumefaciens offers a low technical entry barrier, low costs and a high degree of flexibility embedded within a rapid and scalable workflow. Recombinant proteins can easily be targeted to different subcellular compartments according to their physicochemical requirements, including post-translational modifications, to ensure optimal yields of high quality product, and to support simple and economical downstream processing. Here we demonstrate the use of a plant transient expression platform based on transfection with A. tumefaciens as essential component of a malaria vaccine development workflow involving screens for expression, solubility and stability using fluorescent fusion

  10. Yellow fever vaccine: comparison of the neurovirulence of new 17D-204 Stamaril™ seed lots and RK 168-73 strain.

    Science.gov (United States)

    Moulin, Jean-Claude; Silvano, Jérémy; Barban, Véronique; Riou, Patrice; Allain, Caroline

    2013-07-01

    The neurovirulence of two new candidate 17D-204 Stamaril™ working seed lots and that of two reference preparations were compared. The Stamaril™ working seed lots have been used for more than twenty years for the manufacturing of vaccines of acceptable safety and efficacy. The preparation designated RK 168-73 and provided by the Robert Koch Institute was used as a reference. It was confirmed that RK 168-73 strain was not a good virus control in our study because it has a very low neurovirulence regarding both the clinical and histopathological scores in comparison with Stamaril™ strain and is not representative of a vaccine known to be satisfactory in use. The results were reinforced by the phenotypic characterization by plaque assay demonstrating that RK 168-73 was very different from the Stamaril™ vaccine, and by sequencing results showing 4 mutations between Stamaril™ and RK 168-73 viruses leading to amino acid differences in the NS4B and envelop proteins. Copyright © 2013 The International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

  11. Molecularly engineered live-attenuated chimeric West Nile/dengue virus vaccines protect rhesus monkeys from West Nile virus

    International Nuclear Information System (INIS)

    Pletnev, Alexander G.; St Claire, Marisa; Elkins, Randy; Speicher, Jim; Murphy, Brian R.; Chanock, Robert M.

    2003-01-01

    Two molecularly engineered, live-attenuated West Nile virus (WN) vaccine candidates were highly attenuated and protective in rhesus monkeys. The vaccine candidates are chimeric viruses (designated WN/DEN4) bearing the membrane precursor and envelope protein genes of WN on a backbone of dengue 4 virus (DEN4) with or without a deletion of 30 nucleotides (Δ30) in the 3' noncoding region of DEN4. Viremia in WN/DEN4- infected monkeys was reduced 100-fold compared to that in WN- or DEN4-infected monkeys. WN/DEN4-3'Δ30 did not cause detectable viremia, indicating that it is even more attenuated for monkeys. These findings indicate that chimerization itself and the presence of the Δ30 mutation independently contribute to the attenuation phenotype for nonhuman primates. Despite their high level of attenuation in monkeys, the chimeras induced a moderate-to-high titer of neutralizing antibodies and prevented viremia in monkeys challenged with WN. The more attenuated vaccine candidate, WN/DEN4-3'Δ30, will be evaluated first in our initial clinical studies

  12. Antibodies specific for hypervariable regions 3 to 5 of the feline immunodeficiency virus envelope glycoprotein are not solely responsible for vaccine-induced acceleration of challenge infection in cats

    NARCIS (Netherlands)

    W. Huisman (Willem); E.J.A. Schrauwen (Eefje); S.D. Pas (Suzan); J.A. Karlas (Jos); G.F. Rimmelzwaan (Guus); A.D.M.E. Osterhaus (Albert)

    2004-01-01

    textabstractIn a previous vaccination study in cats, the authors reported on accelerated feline immunodeficiency virus (FIV) replication upon challenge in animals vaccinated with a candidate envelope subunit vaccine. Plasma transfer studies as well as antibody profiles in vaccinated cats indicated a

  13. High Antigen Dose Is Detrimental to Post-Exposure Vaccine Protection against Tuberculosis.

    Science.gov (United States)

    Billeskov, Rolf; Lindenstrøm, Thomas; Woodworth, Joshua; Vilaplana, Cristina; Cardona, Pere-Joan; Cassidy, Joseph P; Mortensen, Rasmus; Agger, Else Marie; Andersen, Peter

    2017-01-01

    Mycobacterium tuberculosis (Mtb), the etiologic agent of tuberculosis (TB), causes 1.8M deaths annually. The current vaccine, BCG, has failed to eradicate TB leaving 25% of the world's population with latent Mtb infection (LTBI), and 5-10% of these people will reactivate and develop active TB. An efficient therapeutic vaccine targeting LTBI could have an enormous impact on global TB incidence, and could be an important aid in fighting multidrug resistance, which is increasing globally. Here we show in a mouse model using the H56 (Ag85B-ESAT-6-Rv2660) TB vaccine candidate that post-exposure, but not preventive, vaccine protection requires low vaccine antigen doses for optimal protection. Loss of protection from high dose post-exposure vaccination was not associated with a loss of overall vaccine response magnitude, but rather with greater differentiation and lower functional avidity of vaccine-specific CD4 T cells. High vaccine antigen dose also led to a decreased ability of vaccine-specific CD4 T cells to home into the Mtb-infected lung parenchyma, a recently discovered important feature of T cell protection in mice. These results underscore the importance of T cell quality rather than magnitude in TB-vaccine protection, and the significant role that antigen dosing plays in vaccine-mediated protection.

  14. Aspergillus vaccines: Hardly worth studying or worthy of hard study?

    Science.gov (United States)

    Levitz, Stuart M

    2017-01-01

    Vaccines rank among the greatest advances in the history of public health. Yet, despite the need, there are no licensed vaccines to protect humans against fungal diseases, including aspergillosis. In this focused review, some of the major scientific and logistical challenges to developing vaccines to protect at-risk individuals against aspergillosis are discussed. Approaches that have shown promise in animal models include vaccines that protect against multiple fungal genera and those that are specifically directed to Aspergillus Advances in proteomics and glycomics have facilitated identification of candidate antigens for use in subunit vaccines. Novel adjuvants and delivery systems are becoming available that can skew vaccine responses toward those associated with protection. Immunotherapy consisting of adoptive transfer of Aspergillus-specific T cells to allogeneic hematopoietic transplant recipients has advanced to human testing but is technically difficult and of unproven benefit. While progress has been impressive, much work still needs to be done if vaccines against aspergillosis are to become a reality. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Virus like particle-based vaccines against emerging infectious disease viruses.

    Science.gov (United States)

    Liu, Jinliang; Dai, Shiyu; Wang, Manli; Hu, Zhihong; Wang, Hualin; Deng, Fei

    2016-08-01

    Emerging infectious diseases are major threats to human health. Most severe viral disease outbreaks occur in developing regions where health conditions are poor. With increased international travel and business, the possibility of eventually transmitting infectious viruses between different countries is increasing. The most effective approach in preventing viral diseases is vaccination. However, vaccines are not currently available for numerous viral diseases. Virus-like particles (VLPs) are engineered vaccine candidates that have been studied for decades. VLPs are constructed by viral protein expression in various expression systems that promote the selfassembly of proteins into structures resembling virus particles. VLPs have antigenicity similar to that of the native virus, but are non-infectious as they lack key viral genetic material. VLP vaccines have attracted considerable research interest because they offer several advantages over traditional vaccines. Studies have shown that VLP vaccines can stimulate both humoral and cellular immune responses, which may offer effective antiviral protection. Here we review recent developments with VLP-based vaccines for several highly virulent emerging or re-emerging infectious diseases. The infectious agents discussed include RNA viruses from different virus families, such as the Arenaviridae, Bunyaviridae, Caliciviridae, Coronaviridae, Filoviridae, Flaviviridae, Orthomyxoviridae, Paramyxoviridae, and Togaviridae families.

  16. Unknown Risks: Parental Hesitation about Vaccination.

    Science.gov (United States)

    Blaisdell, Laura L; Gutheil, Caitlin; Hootsmans, Norbert A M; Han, Paul K J

    2016-05-01

    This qualitative study of a select sample of vaccine-hesitant parents (VHPs) explores perceived and constructed personal judgments about the risks and uncertainties associated with vaccines and vaccine-preventable diseases (VPDs) and how these subjective risk judgments influence parents' decisions about childhood vaccination. The study employed semistructured focus group interviews with 42 VHPs to elicit parents' perceptions and thought processes regarding the risks associated with vaccination and nonvaccination, the sources of these perceptions, and their approach to decision making about vaccination for their children. VHPs engage in various reasoning processes and tend to perceive risks of vaccination as greater than the risks of VPDs. At the same time, VHPs engage in other reasoning processes that lead them to perceive ambiguity in information about the harms of vaccination-citing concerns about the missing, conflicting, changing, or otherwise unreliable nature of information. VHPs' refusal of vaccination may reflect their aversion to both the risk and ambiguity they perceive to be associated with vaccination. Mitigating this vaccine hesitancy likely requires reconstructing the risks and ambiguities associated with vaccination-a challenging task that requires providing parents with meaningful evidence-based information on the known risks of vaccination versus VPDs and explicitly acknowledging the risks that remain truly unknown. © The Author(s) 2015.

  17. The Progress of Therapeutic Vaccination with Regard to Tuberculosis.

    Science.gov (United States)

    Cardona, Pere-Joan

    2016-01-01

    A major problem with tuberculosis (TB) control is the long duration of drug therapy-both for latent and for active TB. Therapeutic vaccination has been postulated to improve this situation, and to this end there are several candidates already in clinical phases of development. These candidates follow two main designs, namely bacilli-directed therapy based on inactivated -whole or -fragmented bacillus ( Mycobacterium w and RUTI) or fusion proteins that integrate non-replicating bacilli -related antigens (H56 vaccine), and host-directed therapy to reduce the tissue destruction. The administration of inactivated Mycobacterium vaccae prevents the "Koch phenomenon" response, and oral administration of heat-killed Mycobacterium manresensis prevents excessive neutrophilic infiltration of the lesions. This review also tries to explain the success of Mycobacterium tuberculosis by reviewing its evolution from infection to disease, and highlights the lack of a definitive understanding of the natural history of TB pathology and the need to improve our knowledge on TB immunology and pathogenesis.

  18. Vaccination with Recombinant Cryptococcus Proteins in Glucan Particles Protects Mice against Cryptococcosis in a Manner Dependent upon Mouse Strain and Cryptococcal Species

    Directory of Open Access Journals (Sweden)

    Charles A. Specht

    2017-11-01

    Full Text Available Development of a vaccine to protect against cryptococcosis is a priority given the enormous global burden of disease in at-risk individuals. Using glucan particles (GPs as a delivery system, we previously demonstrated that mice vaccinated with crude Cryptococcus-derived alkaline extracts were protected against lethal challenge with Cryptococcus neoformans and Cryptococcus gattii. The goal of the present study was to identify protective protein antigens that could be used in a subunit vaccine. Using biased and unbiased approaches, six candidate antigens (Cda1, Cda2, Cda3, Fpd1, MP88, and Sod1 were selected, recombinantly expressed in Escherichia coli, purified, and loaded into GPs. Three mouse strains (C57BL/6, BALB/c, and DR4 were then vaccinated with the antigen-laden GPs, following which they received a pulmonary challenge with virulent C. neoformans and C. gattii strains. Four candidate vaccines (GP-Cda1, GP-Cda2, GP-Cda3, and GP-Sod1 afforded a significant survival advantage in at least one mouse model; some vaccine combinations provided added protection over that seen with either antigen alone. Vaccine-mediated protection against C. neoformans did not necessarily predict protection against C. gattii. Vaccinated mice developed pulmonary inflammatory responses that effectively contained the infection; many surviving mice developed sterilizing immunity. Predicted T helper cell epitopes differed between mouse strains and in the degree to which they matched epitopes predicted in humans. Thus, we have discovered cryptococcal proteins that make promising candidate vaccine antigens. Protection varied depending on the mouse strain and cryptococcal species, suggesting that a successful human subunit vaccine will need to contain multiple antigens, including ones that are species specific.

  19. Decreased vaccine antibody titers following exposure to multiple metals and metalloids in e-waste-exposed preschool children.

    Science.gov (United States)

    Lin, Xinjiang; Xu, Xijin; Zeng, Xiang; Xu, Long; Zeng, Zhijun; Huo, Xia

    2017-01-01

    We explored acquired immunity resulting from vaccination in 3 to 7-year-old children, chronically exposed to multiple heavy metals and metalloids, in an e-waste recycling area (Guiyu, China). Child blood levels of ten heavy metals and metalloids, including lead (Pb), arsenic (As), mercury (Hg), chromium (Cr), cadmium (Cd), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn) and selenium (Se), and seven vaccine antibodies (diphtheria, pertussis, tetanus, hepatitis B, Japanese encephalitis, polio, measles) were measured. The exposed group had higher levels of blood Pb, Mn, Cu, Zn and Cr compared to the reference group (P 10 μg/dL) and high blood Cu and Zn (upper median value of each group) to be inversely associated with seven antibody titers. Antibody titers increased with age, BMI, high blood Mn (>15 μg/L), and high blood Cd and Ni (upper median value of each group). Results suggest multiple heavy metal and metalloid exposure, especially to Pb, Zn and Cu, may be a risk factor inhibiting the development of child immunity, resulting in decreased child antibody levels against vaccines. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Bacillus subtilis spore with surface display of paramyosin from Clonorchis sinensis potentializes a promising oral vaccine candidate.

    Science.gov (United States)

    Sun, Hengchang; Lin, Zhipeng; Zhao, Lu; Chen, Tingjin; Shang, Mei; Jiang, Hongye; Tang, Zeli; Zhou, Xinyi; Shi, Mengchen; Zhou, Lina; Ren, Pengli; Qu, Honglin; Lin, Jinsi; Li, Xuerong; Xu, Jin; Huang, Yan; Yu, Xinbing

    2018-03-07

    Clonorchiasis caused by Clonorchis sinensis has become increasingly prevalent in recent years. Effective prevention strategies are urgently needed to control this food-borne infectious disease. Previous studies indicated that paramyosin of C. sinensis (CsPmy) is a potential vaccine candidate. We constructed a recombinant plasmid of PEB03-CotC-CsPmy, transformed it into Bacillus subtilis WB600 strain (B.s-CotC-CsPmy), and confirmed CsPmy expression on the spore surface by SDS-PAGE, Western blotting and immunofluorescence assay. The immune response and protective efficacy of the recombinant spore were investigated in BALB/c mice after intragastrical or intraperitoneal immunization. Additionally, biochemical enzyme activities in sera, the intestinal histopathology and gut microflora of spore-treated mice were investigated. CsPmy was successfully expressed on the spore surface and the fusion protein on the spore surface with thermostability. Specific IgG in sera and intestinal mucus were increased after intraperitoneal and intragastrical immunization. The sIgA level in intestinal mucus, feces and bile of B.s-CotC-CsPmy orally treated mice were also significantly raised. Furthermore, numerous IgA-secreting cells were detected in intestinal mucosa of intragastrically immunized mice. No inflammatory injury was observed in the intestinal tissues and there was no significant difference in levels of enzyme-indicated liver function among the groups. Additionally, the diversity and abundance of gut microbiota were not changed after oral immunization. Intragastric and intraperitoneal immunization of B.s-CotC-CsPmy spores in mice resulted in egg reduction rates of 48.3 and 51.2% after challenge infection, respectively. Liver fibrosis degree in B.s-CotC-CsPmy spores treated groups was also significantly reduced. CsPmy expressed on the spore surface maintained its immunogenicity. Both intragastrical and intraperitoneal immunization with B.s-CotC-CsPmy spores induced systemic and