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Sample records for candidate protective antigens

  1. Proteome-wide antigen discovery of novel protective vaccine candidates against Staphylococcus aureus infection

    DEFF Research Database (Denmark)

    Rasmussen, Karina Juhl; Mattsson, Andreas Holm; Pilely, Katrine;

    2016-01-01

    Methicillin-resistant Staphylococcus aureus (MRSA) is a rapidly growing problem, especially in hospitals where MRSA cause increased morbidity and mortality and a significant rise in health expenditures. As many strains of MRSA are resistant to other antimicrobials in addition to methicillin......-five different S. aureus proteins were identified, recombinantly expressed, and tested for protection in a lethal sepsis mouse model using S. aureus strain MRSA252 as the challenge organism. We found that 13 of the 35 recombinant peptides yielded significant protection and that 12 of these antigens were highly...

  2. Immunogenicity and protective efficacy of recombinant Modified Vaccinia virus Ankara candidate vaccines delivering West Nile virus envelope antigens.

    Science.gov (United States)

    Volz, Asisa; Lim, Stephanie; Kaserer, Martina; Lülf, Anna; Marr, Lisa; Jany, Sylvia; Deeg, Cornelia A; Pijlman, Gorben P; Koraka, Penelope; Osterhaus, Albert D M E; Martina, Byron E; Sutter, Gerd

    2016-04-07

    West Nile virus (WNV) cycles between insects and wild birds, and is transmitted via mosquito vectors to horses and humans, potentially causing severe neuroinvasive disease. Modified Vaccinia virus Ankara (MVA) is an advanced viral vector for developing new recombinant vaccines against infectious diseases and cancer. Here, we generated and evaluated recombinant MVA candidate vaccines that deliver WNV envelope (E) antigens and fulfil all the requirements to proceed to clinical testing in humans. Infections of human and equine cell cultures with recombinant MVA demonstrated efficient synthesis and secretion of WNV envelope proteins in mammalian cells non-permissive for MVA replication. Prime-boost immunizations in BALB/c mice readily induced circulating serum antibodies binding to recombinant WNV E protein and neutralizing WNV in tissue culture infections. Vaccinations in HLA-A2.1-/HLA-DR1-transgenic H-2 class I-/class II-knockout mice elicited WNV E-specific CD8+ T cell responses. Moreover, the MVA-WNV candidate vaccines protected C57BL/6 mice against lineage 1 and lineage 2 WNV infection and induced heterologous neutralizing antibodies. Thus, further studies are warranted to evaluate these recombinant MVA-WNV vaccines in other preclinical models and use them as candidate vaccine in humans.

  3. Combination of two candidate subunit vaccine antigens elicits protective immunity to ricin and anthrax toxin in mice.

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    Vance, David J; Rong, Yinghui; Brey, Robert N; Mantis, Nicholas J

    2015-01-09

    In an effort to develop combination vaccines for biodefense, we evaluated a ricin subunit antigen, RiVax, given in conjunction with an anthrax protective antigen, DNI. The combination led to high endpoint titer antibody response, neutralizing antibodies, and protective immunity against ricin and anthrax lethal toxin. This is a natural combination vaccine, since both antigens are recombinant subunit proteins that would be given to the same target population.

  4. Antigenic community between Schistosoma mansoni and Biomphalaria glabrata: on the search of candidate antigens for vaccines

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    N Chacón

    2002-10-01

    Full Text Available We have previously confirmed the presence of common antigens between Schistosoma mansoni and its vector, Biomphalaria glabrata. Cross-reactive antigens may be important as possible candidates for vaccine and diagnosis of schistosomiasis. Sera from outbred mice immunized with a soluble Biomphalaria glabrata antigen (SBgA of non-infected B. glabrata snails recognized molecules of SBgA itself and S. mansoni AWA by Western blot. Recognition of several molecules of the SBgA were inhibited by pre-incubation with AWA (16, 30, 36, 60 and 155 kDa. The only specific molecule of AWA, inhibited by SBgA, was a 120 kDa protein. In order to determine which epitopes of SBgA were glycoproteins, the antigen was treated with sodium metaperiodate and compared with non-treated antigen. Molecules of 140, 60 and 24 kDa in the SBgA appear to be glycoproteins. Possible protective effects of the SBgA were evaluated immunizing outbred mice in two different experiments using Freund's Adjuvant. In the first one (12 mice/group, we obtained a significant level of protection (46% in the total worm load, with a high variability in worm recovery. In the second experiment (22 mice/group, no significant protection was observed, neither in worm load nor in egg production per female. Our results suggest that SBgA constitutes a rich source of candidate antigens for diagnosis and prophylactic studies.

  5. Identification of protective antigens for vaccination against systemic salmonellosis

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    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.

  6. New Zika Vaccine Candidate Provides Powerful Protection

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_163384.html New Zika Vaccine Candidate Provides Powerful Protection Made without live ... HealthDay News) -- A single dose of an experimental Zika vaccine protected mice and monkeys from the virus, ...

  7. 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.

  8. Detection of candidal antigens in autoimmune polyglandular syndrome type I.

    OpenAIRE

    Peterson, P; Perheentupa, J; Krohn, K J

    1996-01-01

    Autoimmune polyglandular syndrome type I (APS I) is associated with chronic mucocutaneous candidiasis. To characterize the antibody responses in this subgroup of Candida albicans infections, we screened a candidal cDNA expression library with patient sera and found four cDNA clones encoding the immunopositive proteins enolase, heat shock protein 90, pyruvate kinase, and alcohol dehydrogenase. The reactivity to these antigens was studied further by immunoprecipitation assays with in vitro-tran...

  9. Identification of Schistosoma mansoni candidate antigens for diagnosis of schistosomiasis

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    Gardenia Braz Figueiredo Carvalho

    2011-11-01

    Full Text Available The development of a more sensitive diagnostic test for schistosomiasis is needed to overcome the limitations of the use of stool examination in low endemic areas. Using parasite antigens in enzyme linked immunosorbent assay is a promising strategy, however a more rational selection of parasite antigens is necessary. In this study we performed in silico analysis of the Schistosoma mansoni genome, using SchistoDB database and bioinformatic tools for screening immunogenic antigens. Based on evidence of expression in all parasite life stage within the definitive host, extracellular or plasmatic membrane localization, low similarity to human and other helminthic proteins and presence of predicted B cell epitopes, six candidates were selected: a glycosylphosphatidylinositol-anchored 200 kDa protein, two putative cytochrome oxidase subunits, two expressed proteins and one hypothetical protein. The recognition in unidimensional and bidimensional Western blot of protein with similar molecular weight and isoelectric point to the selected antigens by sera from S. mansoni infected mice indicate a good correlation between these two approaches in selecting immunogenic proteins.

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

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    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.

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

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    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. Immunodiagnosis of porcine cysticercosis: identification of candidate antigens through immunoproteomics.

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    Diaz-Masmela, Yuliet; Fragoso, Gladis; Ambrosio, Javier R; Mendoza-Hernández, Guillermo; Rosas, Gabriela; Estrada, Karel; Carrero, Julio César; Sciutto, Edda; Laclette, Juan P; Bobes, Raúl J

    2013-12-01

    Cysticercosis, caused by the larval stage of Taenia solium, is a zoonotic disease affecting pigs and humans that is endemic to developing countries in Latin America, Africa and South East Asia. The prevalence of infection in pigs, the intermediate host for T. solium, has been used as an indicator for monitoring disease transmission in endemic areas. However, accurate and specific diagnostic tools for porcine cysticercosis remain to be established. Using proteomic approaches and the T. solium genome sequence, seven antigens were identified as specific for porcine cysticercosis, namely, tropomyosin 2, alpha-1 tubulin, beta-tubulin 2, annexin B1, small heat-shock protein, 14-3-3 protein, and cAMP-dependent protein kinase. None of these proteins were cross-reactive when tested with sera from pigs infected with Ascaris spp., Cysticercus tenuicollis and hydatid cysts of Echinococcus spp. or with serum from a Taenia saginata-infected cow. Comparison with orthologues, indicated that the amino acid sequences of annexin B1 and cAMP-dependent protein kinase possessed highly specific regions, which might make them suitable candidates for development of a specific diagnostic assay for porcine cysticercosis.

  13. Selection of protective antigens in Lawsonia intracellularis by reverse vaccinology

    DEFF Research Database (Denmark)

    Vadekær, Dorte Fink; Lundegaard, Claus; Riber, Ulla;

    Lawsonia intracellularis is a bacterial pathogen that infects intestinal epithelial cells in pigs. This causes proliferative enteropathy, which is characterized by diarrhea and reduced growth, and L. intracellularis infection is one of the main reasons for antibiotic treatment of production pigs...... in Denmark. Experimental challenge studies previously performed at DTU-Vet show that a primary infection results in complete protection against reinfection due to induction of immunological memory. We aim to develop a subunit vaccine that mimics the induction of the immune response and hence causes...... membrane proteins, and these were analyzed and given a score for presence of B and T cell epitopes. Using another in silico technology platform, which identifies novel B cell antigens eliciting a highly protective immune response, we obtained a second list of potential vaccine candidates. Six proteins were...

  14. Protective antigens against glanders identified by expression library immunization.

    Science.gov (United States)

    Whitlock, Gregory C; Robida, Mark D; Judy, Barbara M; Qazi, Omar; Brown, Katherine A; Deeraksa, Arpaporn; Taylor, Katherine; Massey, Shane; Loskutov, Andrey; Borovkov, Alex Y; Brown, Kevin; Cano, Jose A; Torres, Alfredo G; Estes, D Mark; Sykes, Kathryn F

    2011-01-01

    Burkholderia are highly evolved Gram-negative bacteria that primarily infect solipeds but are transmitted to humans by ingestion and cutaneous or aerosol exposures. Heightened concern over human infections of Burkholderia mallei and the very closely related species B. pseudomallei is due to the pathogens' proven effectiveness as bioweapons, and to the increased potential for natural opportunistic infections in the growing diabetic and immuno-compromised populations. These Burkholderia species are nearly impervious to antibiotic treatments and no vaccine exists. In this study, the genome of the highly virulent B. mallei ATCC23344 strain was examined by expression library immunization for gene-encoded protective antigens. This protocol for genomic-scale functional screening was customized to accommodate the unusually large complexity of Burkholderia, and yielded 12 new putative vaccine candidates. Five of the candidates were individually tested as protein immunogens and three were found to confer significant partial protection against a lethal pulmonary infection in a murine model of disease. Determinations of peripheral blood cytokine and chemokine profiles following individual protein immunizations show that interleukin-2 (IL-2) and IL-4 are elicited by the three confirmed candidates, but unexpectedly interferon-γ and tumor necrosis factor-α are not. We suggest that these pathogen components, discovered using genetic immunization and confirmed in a conventional protein format, will be useful toward the development of a safe and effective glanders vaccine.

  15. Protective antigens against glanders identified by expression library immunization

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    Gregory C. Whitlock

    2011-11-01

    Full Text Available Burkholderia are highly evolved Gram-negative bacteria that primarily infect solipeds but are transmitted to humans by ingestion and cutaneous or aerosol exposures. Heightened concern over human infections of Burkholderia (B. mallei and the very closely related species B. pseudomallei is due to the pathogens’ proven effectiveness as bioweapons, and to the increased potential for natural opportunistic infections in the growing diabetic and immuno-compromised populations. These Burkholderia species are nearly impervious to antibiotic treatments and no vaccine exists. In this study, the genome of the highly virulent B. mallei ATCC23344 strain was examined by expression library immunization for gene-encoded protective antigens. This protocol for genomic-scale functional screening was customized to accommodate the unusually large complexity of Burkholderia, and yielded 12 new putative vaccine candidates. Five of the candidates were individually tested as protein immunogens and three were found to confer significant partial protection against a lethal pulmonary infection in a murine model of disease. Determinations of peripheral blood cytokine and chemokine profiles following individual protein immunizations show that IL-2 and IL-4 are elicited by the three confirmed candidates, but unexpectedly interferon-and tumor necrosis factor-are not. We suggest that these pathogen components, discovered using genetic immunization and confirmed in a conventional protein format, will be useful toward the development of a safe and effective glanders vaccine.

  16. Genetic mapping identifies novel highly protective antigens for an apicomplexan parasite.

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    Damer P Blake

    Full Text Available Apicomplexan parasites are responsible for a myriad of diseases in humans and livestock; yet despite intensive effort, development of effective sub-unit vaccines remains a long-term goal. Antigenic complexity and our inability to identify protective antigens from the pool that induce response are serious challenges in the development of new vaccines. Using a combination of parasite genetics and selective barriers with population-based genetic fingerprinting, we have identified that immunity against the most important apicomplexan parasite of livestock (Eimeria spp. was targeted against a few discrete regions of the genome. Herein we report the identification of six genomic regions and, within two of those loci, the identification of true protective antigens that confer immunity as sub-unit vaccines. The first of these is an Eimeria maxima homologue of apical membrane antigen-1 (AMA-1 and the second is a previously uncharacterised gene that we have termed 'immune mapped protein-1' (IMP-1. Significantly, homologues of the AMA-1 antigen are protective with a range of apicomplexan parasites including Plasmodium spp., which suggest that there may be some characteristic(s of protective antigens shared across this diverse group of parasites. Interestingly, homologues of the IMP-1 antigen, which is protective against E. maxima infection, can be identified in Toxoplasma gondii and Neospora caninum. Overall, this study documents the discovery of novel protective antigens using a population-based genetic mapping approach allied with a protection-based screen of candidate genes. The identification of AMA-1 and IMP-1 represents a substantial step towards development of an effective anti-eimerian sub-unit vaccine and raises the possibility of identification of novel antigens for other apicomplexan parasites. Moreover, validation of the parasite genetics approach to identify effective antigens supports its adoption in other parasite systems where legitimate

  17. Antigenicity and diagnostic potential of vaccine candidates in human Chagas disease.

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    Shivali Gupta

    Full Text Available BACKGROUND: Chagas disease, caused by Trypanosoma cruzi, is endemic in Latin America and an emerging infectious disease in the US and Europe. We have shown TcG1, TcG2, and TcG4 antigens elicit protective immunity to T. cruzi in mice and dogs. Herein, we investigated antigenicity of the recombinant proteins in humans to determine their potential utility for the development of next generation diagnostics for screening of T. cruzi infection and Chagas disease. METHODS AND RESULTS: Sera samples from inhabitants of the endemic areas of Argentina-Bolivia and Mexico-Guatemala were analyzed in 1(st-phase for anti-T. cruzi antibody response by traditional serology tests; and in 2(nd-phase for antibody response to the recombinant antigens (individually or mixed by an ELISA. We noted similar antibody response to candidate antigens in sera samples from inhabitants of Argentina and Mexico (n=175. The IgG antibodies to TcG1, TcG2, and TcG4 (individually and TcG(mix were present in 62-71%, 65-78% and 72-82%, and 89-93% of the subjects, respectively, identified to be seropositive by traditional serology. Recombinant TcG1- (93.6%, TcG2- (96%, TcG4- (94.6% and TcG(mix- (98% based ELISA exhibited significantly higher specificity compared to that noted for T. cruzi trypomastigote-based ELISA (77.8% in diagnosing T. cruzi-infection and avoiding cross-reactivity to Leishmania spp. No significant correlation was noted in the sera levels of antibody response and clinical severity of Chagas disease in seropositive subjects. CONCLUSIONS: Three candidate antigens were recognized by antibody response in chagasic patients from two distinct study sites and expressed in diverse strains of the circulating parasites. A multiplex ELISA detecting antibody response to three antigens was highly sensitive and specific in diagnosing T. cruzi infection in humans, suggesting that a diagnostic kit based on TcG1, TcG2 and TcG4 recombinant proteins will be useful in diverse situations.

  18. 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

    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....

  19. Recombinant Rhipicephalus appendiculatus gut (Ra86 and salivary gland cement (Trp64 proteins as candidate antigens for inclusion in tick vaccines: protective effects of Ra86 on infestation with adult R. appendiculatus

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    Saimo M

    2011-11-01

    Full Text Available Margaret Saimo1,2,*, David O Odongo3,4,*, Stephen Mwaura3, Just M Vlak1, Anthony J Musoke5, George W Lubega2, Richard P Bishop3, Monique M van Oers11Laboratory of Virology, Wageningen University, Wageningen, The Netherlands; 2School of Veterinary Medicine, Makerere University, Kampala, Uganda; 3International Livestock Research Institute, Nairobi, Kenya; 4School of Biological Sciences, University of Nairobi, Nairobi, Kenya; 5Onderstepoort Veterinary Institute, Onderstepoort, Pretoria, South Africa *These two authors made an equal contribution to this workAbstract: Rhipicephalus appendiculatus gut protein Ra86 (variants Ra85A and Ra92A and the salivary gland cement protein (Trp64 were expressed in the baculovirus-insect cell system. The recombinant gut proteins expressed as soluble proteins and the recombinant cement protein, as insoluble inclusion bodies, were used to immunize rabbits, which were then challenged with larval, nymphal, and adult stages of R. appendiculatus ticks. High tick mortality (23.3% occurred on adult ticks that fed on rabbits vaccinated with the gut proteins, compared with 1.9% mortality in ticks that fed on unvaccinated naïve control rabbits. The mean weight of engorged female ticks was significantly reduced by 31.5% in rabbits vaccinated with the Ra86 recombinant protein compared with controls, as was egg production. Marked effects on these parameters were also observed in adult ticks as a result from vaccination using Trp64, but these were not statistically significant. For both antigens, there was no demonstrable effect on larval or nymphal ticks. This study demonstrates for the first time the protective efficacy of a homolog of Boophilus microplus Bm86 in reducing tick infestation by the adult stage of the three-host tick R. appendiculatus. The results demonstrate the potential of Ra86 for vaccine development against this tick and for the control of East Coast fever.Keywords: baculovirus, Ra85A, Ra92A, Boophilus

  20. Atomic structure of anthrax protective antigen pore elucidates toxin translocation.

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    Jiang, Jiansen; Pentelute, Bradley L; Collier, R John; Zhou, Z Hong

    2015-05-28

    Anthrax toxin, comprising protective antigen, lethal factor, and oedema factor, is the major virulence factor of Bacillus anthracis, an agent that causes high mortality in humans and animals. Protective antigen forms oligomeric prepores that undergo conversion to membrane-spanning pores by endosomal acidification, and these pores translocate the enzymes lethal factor and oedema factor into the cytosol of target cells. Protective antigen is not only a vaccine component and therapeutic target for anthrax infections but also an excellent model system for understanding the mechanism of protein translocation. On the basis of biochemical and electrophysiological results, researchers have proposed that a phi (Φ)-clamp composed of phenylalanine (Phe)427 residues of protective antigen catalyses protein translocation via a charge-state-dependent Brownian ratchet. Although atomic structures of protective antigen prepores are available, how protective antigen senses low pH, converts to active pore, and translocates lethal factor and oedema factor are not well defined without an atomic model of its pore. Here, by cryo-electron microscopy with direct electron counting, we determine the protective antigen pore structure at 2.9-Å resolution. The structure reveals the long-sought-after catalytic Φ-clamp and the membrane-spanning translocation channel, and supports the Brownian ratchet model for protein translocation. Comparisons of four structures reveal conformational changes in prepore to pore conversion that support a multi-step mechanism by which low pH is sensed and the membrane-spanning channel is formed.

  1. Comprehensive antigen screening identifies Moraxella catarrhalis proteins that induce protection in a mouse pulmonary clearance model.

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    Margarita Smidt

    Full Text Available Moraxella catarrhalis is one of the three most common causative bacterial pathogens of otitis media, however no effective vaccine against M. catarrhalis has been developed so far. To identify M. catarrhalis vaccine candidate antigens, we used carefully selected sera from children with otitis media and healthy individuals to screen small-fragment genomic libraries that are expressed to display frame-selected peptides on a bacterial cell surface. This ANTIGENome technology led to the identification of 214 antigens, 23 of which were selected by in vitro or in vivo studies for additional characterization. Eight of the 23 candidates were tested in a Moraxella mouse pulmonary clearance model, and 3 of these antigens induced significantly faster bacterial clearance compared to adjuvant or to the previously characterized antigen OmpCD. The most significant protection data were obtained with the antigen MCR_1416 (Msp22, which was further investigated for its biological function by in vitro studies suggesting that Msp22 is a heme binding protein. This study comprises one of the most exhaustive studies to identify potential vaccine candidate antigens against the bacterial pathogen M. catarrhalis.

  2. Cross-protection provided by live Shigella mutants lacking major antigens.

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    Szijártó, Valéria; Hunyadi-Gulyás, Eva; Emődy, Levente; Pál, Tibor; Nagy, Gábor

    2013-05-01

    The immune response elicited by Shigella infections is dominated by serotype-specific antibodies recognizing the LPS O-antigens. Although a marked antibody response to invasion plasmid antigens (Ipa-s) shared by all virulent strains is also induced, the varying level of immunity elicited by natural infections is serotype-restricted. Previous vaccines have tried to mimic and achieve this serotype-specific, infection-induced immunity. As, however, the four Shigella species can express 50 different types of O-antigens, current approaches with the aim to induce a broad coverage use a mixture of the most common O-antigens combined in single vaccines. In the current study we present data on an alternative approach to generate immunity protective against multiple serotypes. Mutants lacking both major immune-determinant structures (i.e. the Ipa and O-antigens) were not only highly attenuated, but, unlike their avirulent counterparts still expressing these antigens, elicited a protective immune response to heterologous serotypes in a murine model. Evidence is provided that protection was mediated by the enhanced immunogenic potential of minor conserved antigens. Furthermore, the rough, non-invasive double mutants triggered an immune response different from that induced by the smooth, invasive strains regarding the isotype of antibodies generated. These non-invasive, rough mutants may represent promising candidates for further development into live vaccines for the prophylaxis of bacillary dysentery in areas with multiple endemic serotypes.

  3. Identification and evaluation of vaccine candidate antigens from the poultry red mite (Dermanyssus gallinae).

    Science.gov (United States)

    Bartley, Kathryn; Wright, Harry W; Huntley, John F; Manson, Erin D T; Inglis, Neil F; McLean, Kevin; Nath, Mintu; Bartley, Yvonne; Nisbet, Alasdair J

    2015-11-01

    An aqueous extract of the haematophagous poultry ectoparasite, Dermanyssus gallinae, was subfractionated using anion exchange chromatography. Six of these subfractions were used to immunise hens and the blood from these hens was fed, in vitro, to poultry red mites. Mite mortality following these feeds was indicative of protective antigens in two of the subfractions, with the risks of mites dying being 3.1 and 3.7 times higher than in the control group (P<0.001). A combination of two-dimensional immunoblotting and immunoaffinity chromatography, using IgY from hens immunised with these subfractions, was used in concert with proteomic analyses to identify the strongest immunogenic proteins in each of these subfractions. Ten of the immunoreactive proteins were selected for assessment as vaccine candidates using the following criteria: intensity of immune recognition; likelihood of exposure of the antigen to the antibodies in a blood meal; proposed function and known vaccine potential of orthologous molecules. Recombinant versions of each of these 10 proteins were produced in Escherichia coli and were used to immunise hens. Subsequent in vitro feeding of mites on blood from these birds indicated that immunisation with Deg-SRP-1 (serpin), Deg-VIT-1 (vitellogenin), Deg-HGP-1 (hemelipoglycoprotein) or Deg-PUF-1 (a protein of unknown function) resulted in significantly increased risk of mite death (1.7-2.8times higher than in mites fed blood from control hens immunised with adjuvant only, P<0.001). The potential for using these antigens in a recombinant vaccine is discussed.

  4. Succinyl-CoA Synthetase: New Antigen Candidate of Bartonella bacilliformis

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    Gomes, Cláudia; Palma, Noemí; Pons, Maria J.; Magallón-Tejada, Ariel; Sandoval, Isabel; Tinco-Valdez, Carmen; Gutarra, Carlos; del Valle-Mendoza, Juana; Ruiz, Joaquim; Matsuoka, Mayumi

    2016-01-01

    Background Bartonella bacilliformis is the causative agent of Carrion’s disease, a neglected illness with mortality rates of 40–85% in the absence of treatment. The lack of a diagnostic technique to overcome misdiagnosis and treat asymptomatic carriers is of note. This study aimed to identify new B. bacilliformis antigenic candidates that could lead to a new diagnostic tool able to be implemented in endemic rural areas. Methodology/Principal Findings Blood (n = 198) and serum (n = 177) samples were collected in northern Peru. Clinical data were recorded. Specific 16S rRNA amplification by RT-PCR, IFA and ELISA for IgM/IgG with whole cells as antigens was done. Western blot analysis and N-terminal amino acid sequencing detected seroreactive proteins. ELISAs for IgM/IgG for the antigenic candidates were performed. Of the population 33.3% reported at least one symptom compatible with Carrion’s disease; 25.4% (IFA), 27.1% (ELISA-IgG), 33.9% (ELISA-IgM) and 38.9% (RT-PCR) of samples were positive. Four proteins were considered potential antigenic candidates, including two new antigenic candidates, succinyl-CoA synthetase subunit α (SCS-α) and succinyl-CoA synthetase subunit β (SCS-β). On Western blot both Pap31 and SCS-α interacted with IgM, while GroEL and SCS-β interacted with IgG. The presence of specific antibodies against the antigenic candidates varied from 34.5% (IgG against SCS-α) to 97.2% (IgM against Pap31). Conclusions/Significance RT-PCR and the high levels of positivity for specific ELISAs demonstrate high levels of B. bacilliformis exposure and asymptomatic carriers among inhabitants. The new antigens identified might be used as a new rapid diagnostic tool to diagnose acute Carrion’s disease and identify asymptomatic carriers. PMID:27627803

  5. Characterization of O-antigen delivered by Generalized Modules for Membrane Antigens (GMMA) vaccine candidates against nontyphoidal Salmonella.

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    De Benedetto, G; Alfini, R; Cescutti, P; Caboni, M; Lanzilao, L; Necchi, F; Saul, A; MacLennan, C A; Rondini, S; Micoli, F

    2017-01-11

    Invasive nontyphoidal Salmonella disease (iNTS) is a leading cause of death and morbidity in Africa. The most common pathogens are Salmonella enterica serovars Typhimurium and Enteritidis. The O-antigen portion of their lipopolysaccharide is a target of protective immunity and vaccines targeting O-antigen are currently in development. Here we investigate the use of Generalized Modules for Membrane Antigens (GMMA) as delivery system for S. Typhimurium and S. Enteritidis O-antigen. Gram-negative bacteria naturally shed outer membrane in a blebbing process. By deletion of the tolR gene, the level of shedding was greatly enhanced. Further genetic modifications were introduced into the GMMA-producing strains in order to reduce reactogenicity, by detoxifying the lipid A moiety of lipopolysaccharide. We found that genetic mutations can impact on expression of O-antigen chains. All S. Enteritidis GMMA characterized had an O-antigen to protein w/w ratio higher than 0.6, while the ratio was 0.7 for S. Typhimurium ΔtolR GMMA, but decreased to less than 0.1 when further mutations for lipid A detoxification were introduced. Changes were also observed in O-antigen chain length and level and/or position of O-acetylation. When tested in mice, the GMMA induced high levels of anti-O-antigen-specific IgG functional antibodies, despite variation in density and O-antigen structural modifications. In conclusion, simplicity of manufacturing process and low costs of production, coupled with encouraging immunogenicity data, make GMMA an attractive strategy to further investigate for the development of a vaccine against iNTS.

  6. Cytolethal distending toxin as virulence factor, protective antigen, and target for vaccine development

    Directory of Open Access Journals (Sweden)

    Lagergård T

    2012-12-01

    Full Text Available Teresa Lagergård,1 Jerry Keith21Institute of Biomedicine, Department of Microbiology and Immunology, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden; 2Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD, NIH, Bethesda, MD, USAAbstract: This review explores the cytolethal distending toxin (CDT as a virulence factor, protective antigen, and a vaccine candidate in diseases caused by the following bacterial pathogens: Haemophilus ducreyi (HdCDT, Aggregatibacter actinomycetemcomitans, Campylobacter jejuni, and Helicobacter hepaticus. The review highlights some of the important evidence indicating that CDT is not only a commonly invoked virulence factor involved in pathogenesis of infection caused by these bacteria, but is also a protective antigen, such that specific antibodies will neutralize cell damage caused by the toxin. This justifies the development of toxoids as vaccine candidates. The first immunogenic toxoid was produced by formaldehyde treatment of HdCDT and has been used to study the involvement of antibodies in protection against infection and its use as a future vaccine component. The development of such toxoid vaccines may facilitate the studies of protection and immunoprophylaxis in diseases caused by CDT-producing bacteria.Keywords: cytolethal distending toxin, virulence factor, protective antigen, Haemophilus ducreyi, Aggregatibacter actinomycetemcomitans, Campylobacter jejuni, toxoid vaccine

  7. Evaluation of a DNA vaccine candidate expressing prM-E-NS1 antigens of dengue virus serotype 1 with or without granulocyte-macrophage colony-stimulating factor (GM-CSF) in immunogenicity and protection.

    Science.gov (United States)

    Zheng, Qun; Fan, Dongying; Gao, Na; Chen, Hui; Wang, Juan; Ming, Ying; Li, Jieqiong; An, Jing

    2011-01-17

    Dengue is one of the most important mosquito-borne viral diseases. In past years, although considerable effort has been put into the development of a vaccine, there is currently no licensed dengue vaccine. In this study, we constructed DNA vaccines that carried the prM-E-NS1 genes of dengue virus serotype 1 (DV1) with or without the granulocyte-macrophage colony-stimulating factor (GM-CSF) gene, an attractive DNA vaccine adjuvant. Immunization with the plasmid pCAG-DV1/E/NS1, which expresses viral prM-E-NS1, or the bicistronic plasmid pCAG-DV1-GM, which co-expresses viral prM-E-NS1 and GM-CSF, resulted in long-term IgG response, high levels of splenocyte-secreted interferon-γ and interleukin-2, strong cytotoxic T lymphocyte activity and sufficient protection in the DV1-challenged mice. This suggested that both humoral and cellular immune responses were induced by the immunizations and that they played important roles in protection against the DV1 challenge. Interestingly, the magnitude, quality and protective capacity of the immune responses induced by immunization with pCAG-DV1/E/NS1 or pCAG-DV1-GM seemed stronger than those induced by pCAG-DV1/E (expressing viral prM-E alone). Taken together, we demonstrated that prM/E plus NS1 would be a suitable solution for the development of a DNA vaccine against DV.

  8. 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 among different GAS strains, upregulated in host-pathogen interaction studies, and predicted to be extracellular or associated with the surface of the bacteria. The antigens were tested for both antibody recognition and T cell responses in human adults and children. The antigenicity of a selected group...

  9. Partial purification of protective antigens from Nippostrongylus brasiliensis in mice.

    Science.gov (United States)

    Rhalem, A; Bourdieu, C; Luffau, G; Pery, P

    1988-01-01

    The purification of antigens from Nippostrongylus brasiliensis, through their ability to provoke cellular proliferation of immune cells and through their recognition by antibodies, led to an antigenic preparation which was extracted from adult worms and which contained only two proteins (MW 14 and 43 Kd). Mice which were vaccinated by the oral route after the entrapment of these two proteins in liposomes were strongly protected.

  10. Identification of candidate antigens from adult stages of Toxocara canis for the serodiagnosis of human toxocariasis

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    Patrícia Longuinhos Peixoto

    2011-03-01

    Full Text Available In the present work, we identified adult Toxocara canis antigens through sodium dodecyl sulfate-polyacrylamide gel electrophoresis for potential use in human toxocariasis immunodiagnosis. The sensitivity and specificity of several semi-purified antigens, as well as their cross-reactivity with other parasitic infections, were assessed by IgM and IgG-enzime linked immunosorbent assay. Whilst we found that the crude extract of the parasite presented limited sensitivity, specificity and high cross-reactivity against other parasites, we identified 42, 58, 68 and 97-kDa semi-purified antigens as the most promising candidates for immunodiagnosis. Moreover, the 58 and 68-kDa antigens presented the lowest IgM cross-reactivity. When tested as a combination, a mixture of the 58 and 68-kDa antigens presented 100% sensitivity and specificity, as well as minor cross-reactivity. Although the combination of the 42, 58, 68 and 97-kDa antigens presented 100% sensitivity at a dilution of 1:40, the low specificity and high cross-reactivity observed suggested a limited use for diagnostic purposes. Our data suggested that the 58 and 68-kDa antigens might be most suitable for the immunodiagnosis of human toxocariasis.

  11. 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.

  12. Conservation of a protective surface antigen of Tritrichomonas foetus.

    Science.gov (United States)

    Ikeda, J S; BonDurant, R H; Campero, C M; Corbeil, L B

    1993-12-01

    Bovine trichomoniasis is a sexually transmitted disease caused by the flagellated protozoan Tritrichomonas foetus. A protective surface antigen was previously identified and immunoaffinity purified from T. foetus isolate D1 with cross-reactive monoclonal antibodies (MAbs) TF1.15 and TF1.17 (BonDurant, R. H., R. R. Corbeil, and L. B. Corbeil, Infect. Immun. 61:1385-1394, 1993). This antigen elicited antibody responses in the serum and cervicovaginal mucus of heifers. Thus, it may be useful as an immunodiagnostic reagent as well as a subunit vaccine. Conservation of the antigen in all strains would be crucial for either application. We investigated the conservation of this antigen among 36 isolates of T. foetus from Argentina, Costa Rica, and the United States using MAbs TF1.15 and TF1.17 in an enzyme-linked immunosorbent assay. MAb TF1.17 reacted with 32 of the 36 isolates, whereas MAb TF1.15 reacted with all of the isolates tested. One of the isolates which did not react with MAb TF1.17 (i.e., D1#3) was investigated further by Western blotting (immunoblotting) to determine the reason for the lack of reactivity with one of the two cross-reactive MAbs. The antigenic band that was reactive with MAb TF1.15 had a molecular mass slightly lower than that of the corresponding band from isolate D1, which reacted with both MAbs TF1.15 and TF1.17. Thus, at least a major portion of the antigen appeared to be conserved. This was confirmed in a study of heifers infected with isolate D1#3. The vaginal immunoglobulin A antibodies of these infected heifers reacted with the antigen of isolate D1 that was immunoaffinity purified with MAb TF1.17. Therefore, even though the epitope recognized by MAb TF1.17 was missing in the challenge isolate (D1#3), the heifers developed an immune response to the rest of the molecule. These results indicate that the major portion of the previously described protective antigen is conserved in different isolates of T. foetus. This portion contains the

  13. Genetic diversity and population structure of genes encoding vaccine candidate antigens of Plasmodium vivax

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    Chenet Stella M

    2012-03-01

    Full Text Available Abstract Background A major concern in malaria vaccine development is genetic polymorphisms typically observed among Plasmodium isolates in different geographical areas across the world. Highly polymorphic regions have been observed in Plasmodium falciparum and Plasmodium vivax antigenic surface proteins such as Circumsporozoite protein (CSP, Duffy-binding protein (DBP, Merozoite surface protein-1 (MSP-1, Apical membrane antigen-1 (AMA-1 and Thrombospondin related anonymous protein (TRAP. Methods Genetic variability was assessed in important polymorphic regions of various vaccine candidate antigens in P. vivax among 106 isolates from the Amazon Region of Loreto, Peru. In addition, genetic diversity determined in Peruvian isolates was compared to population studies from various geographical locations worldwide. Results The structured diversity found in P. vivax populations did not show a geographic pattern and haplotypes from all gene candidates were distributed worldwide. In addition, evidence of balancing selection was found in polymorphic regions of the trap, dbp and ama-1 genes. Conclusions It is important to have a good representation of the haplotypes circulating worldwide when implementing a vaccine, regardless of the geographic region of deployment since selective pressure plays an important role in structuring antigen diversity.

  14. Genetic diversity of vaccine candidate antigens in Plasmodium falciparum isolates from the Amazon basin of Peru

    Directory of Open Access Journals (Sweden)

    Lucas Carmen M

    2008-05-01

    Full Text Available Abstract Background Several of the intended Plasmodium falciparum vaccine candidate antigens are highly polymorphic and could render a vaccine ineffective if their antigenic sites were not represented in the vaccine. In this study, characterization of genetic variability was performed in major B and T-cell epitopes within vaccine candidate antigens in isolates of P. falciparum from Peru. Methods DNA sequencing analysis was completed on 139 isolates of P. falciparum collected from endemic areas of the Amazon basin in Loreto, Peru from years 1998 to 2006. Genetic diversity was determined in immunological important regions in circumsporozoite protein (CSP, merozoite surface protein-1 (MSP-1, apical membrane antigen-1 (AMA-1, liver stage antigen-1 (LSA-1 and thrombospondin-related anonymous protein (TRAP. Alleles identified by DNA sequencing were aligned with the vaccine strain 3D7 and DNA polymorphism analysis and FST study-year pairwise comparisons were done using the DnaSP software. Multilocus analysis (MLA was performed and average of expected heterozygosity was calculated for each loci and haplotype over time. Results Three different alleles for CSP, seven for MSP-1 Block 2, one for MSP-1 Block 17, three for AMA-1 and for LSA-1 each and one for TRAP were identified. There were 24 different haplotypes in 125 infections with complete locus typing for each gene. Conclusion Characterization of the genetic diversity in Plasmodium isolates from the Amazon Region of Peru showed that P. falciparum T and B cell epitopes in these antigens have polymorphisms more similar to India than to Africa. These findings are helpful in the formulation of a vaccine considering restricted repertoire populations.

  15. Cloning of the Protective Antigen Gene of Bacillus anthracis

    Science.gov (United States)

    1983-09-01

    of the complicated precedents of duplicate toxin genes in chro- muumm mosomall and plasmid DNA of B. thuringiensis (Schnepf and Whitely, 1981; Klier...OiL V4. 34. S-W7. SW 1v 99 CwI 0193 by MT 0 009-7483/06O-002.00/0 mU"- - 1*;)-0Cloning of the Protective Antigen Gene OCT 19 MI L Sof Bacillus ...Sumnler uncertain, it is probably caused by other Bacillus antigens, 4 t which may include LF and EF. PA produced from recom- A The - "w t of a

  16. A candidate H1N1 pandemic influenza vaccine elicits protective immunity in mice.

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    Julia Steitz

    Full Text Available BACKGROUND: In 2009 a new pandemic disease appeared and spread globally. The recent emergence of the pandemic influenza virus H1N1 first isolated in Mexico and USA raised concerns about vaccine availability. We here report our development of an adenovirus-based influenza H1N1 vaccine tested for immunogenicity and efficacy to confer protection in animal model. METHODS: We generated two adenovirus(Ad5-based influenza vaccine candidates encoding the wildtype or a codon-optimized hemagglutinin antigen (HA from the recently emerged swine influenza isolate A/California/04/2009 (H1N1pdm. After verification of antigen expression, immunogenicity of the vaccine candidates were tested in a mouse model using dose escalations for subcutaneous immunization. Sera of immunized animals were tested in microneutalization and hemagglutination inhibition assays for the presence of HA-specific antibodies. HA-specific T-cells were measured in IFNgamma Elispot assays. The efficiency of the influenza vaccine candidates were evaluated in a challenge model by measuring viral titer in lung and nasal turbinate 3 days after inoculation of a homologous H1N1 virus. CONCLUSIONS/SIGNIFICANCE: A single immunization resulted in robust cellular and humoral immune response. Remarkably, the intensity of the immune response was substantially enhanced with codon-optimized antigen, indicating the benefit of manipulating the genetic code of HA antigens in the context of recombinant influenza vaccine design. These results highlight the value of advanced technologies in vaccine development and deployment in response to infections with pandemic potential. Our study emphasizes the potential of an adenoviral-based influenza vaccine platform with the benefits of speed of manufacture and efficacy of a single dose immunization.

  17. Potentiation of anthrax vaccines using protective antigen-expressing viral replicon vectors.

    Science.gov (United States)

    Wang, Hai-Chao; An, Huai-Jie; Yu, Yun-Zhou; Xu, Qing

    2015-02-01

    DNA vaccines require improvement for human use because they are generally weak stimulators of the immune system in humans. The efficacy of DNA vaccines can be improved using a viral replicon as vector to administer antigen of pathogen. In this study, we comprehensively evaluated the conventional non-viral DNA, viral replicon DNA or viral replicon particles (VRP) vaccines encoding different forms of anthrax protective antigen (PA) for specific immunity and protective potency against anthrax. Our current results clearly suggested that these viral replicon DNA or VRP vaccines derived from Semliki Forest virus (SFV) induced stronger PA-specific immune responses than the conventional non-viral DNA vaccines when encoding the same antigen forms, which resulted in potent protection against challenge with the Bacillus anthracis strain A16R. Additionally, the naked PA-expressing SFV replicon DNA or VRP vaccines without the need for high doses or demanding particular delivery regimens elicited robust immune responses and afforded completely protective potencies, which indicated the potential of the SFV replicon as vector of anthrax vaccines for use in clinical application. Therefore, our results suggest that these PA-expressing SFV replicon DNA or VRP vaccines may be suitable as candidate vaccines against anthrax.

  18. Cloning and Expressing Recombinant Protective Antigen Domains of B. anthracis

    Science.gov (United States)

    2011-09-01

    Army Research Laboratory: 2010; p 19. 18. Sambrook, J.; Fritsch, E. F.; Maniatis , T. Molecular Cloning : A Laboratory Manual. 2nd ed.; Cold Spring...on a rotating platform until not viscous (adapted from Molecular Cloning : A Laboratory Manual) (18). Each solution was centrifuged at 45,000 x g for... Cloning and Expressing Recombinant Protective Antigen Domains of B. anthracis by Deborah A. Sarkes, Joshua M. Kogot, Irene Val-Addo

  19. Self-Adjuvanting Bacterial Vectors Expressing Pre-Erythrocytic Antigens Induce Sterile Protection against Malaria

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    Elke eBergmann-Leitner

    2013-07-01

    Full Text Available Genetically inactivated, Gram-negative bacteria that express malaria vaccine candidates represent a promising novel self-adjuvanting vaccine approach. Antigens expressed on particulate bacterial carriers not only target directly to antigen-presenting cells but also provide a strong danger signal thus circumventing the requirement for potent extraneous adjuvants. E. coli expressing malarial antigens resulted in the induction of either Th1 or Th2 biased responses that were dependent on both antigen and sub-cellular localization. Some of these constructs induced higher quality humoral responses compared to recombinant protein and most importantly they were able to induce sterile protection against sporozoite challenge in a murine model of malaria. In light of these encouraging results, two major Plasmodium falciparum pre-erythrocytic malaria vaccine targets, the Cell-Traversal protein for Ookinetes and Sporozoites (CelTOS fused to the Maltose-binding protein in the periplasmic space and the Circumsporozoite Protein (CSP fused to the Outer membrane protein A in the outer membrane were expressed in a clinically relevant, attenuated Shigella strain (Shigella flexneri 2a. This type of live attenuated vector has previously undergone clinical investigations as a vaccine against shigellosis. Using this novel delivery platform for malaria, we find that vaccination with the whole organism represents an effective vaccination alternative that induces protective efficacy against sporozoite challenge. Shigella GeMI-Vax expressing malaria targets warrant further evaluation to determine their full potential as a dual disease, multivalent, self-adjuvanting vaccine system, against both shigellosis and malaria.

  20. Isolation of a novel gene from Photobacterium damselae subsp. piscicida and analysis of the recombinant antigen as promising vaccine candidate.

    Science.gov (United States)

    Andreoni, Francesca; Boiani, Romina; Serafini, Giordano; Amagliani, Giulia; Dominici, Sabrina; Riccioni, Giulia; Zaccone, Renata; Mancuso, Monique; Scapigliati, Giuseppe; Magnani, Mauro

    2013-01-21

    Photobacterium damselae subsp. piscicida (PDP) is the causative agent of fish pasteurellosis, a bacterial disease causing important losses in marine aquaculture. Vaccines against the pathogen can be a way to control the infection and avoid antibiotic treatments. However, a satisfactory protective vaccine against fish pasteurellosis is not commercially available. In this study, a biotechnogical approach based on reverse vaccinology has been used to identify potential vaccine candidates for the development of a recombinant subunit vaccine. Genome sequencing of clones from a genomic cosmid library of PDP and in silico selection of the surface exposed proteins were the initial steps in vaccine candidate identification. From 370 open reading frames (ORF) eight potential antigens were selected, expressed as recombinant proteins and purified. These vaccine candidates were used to generate specific polyclonal antibodies in mice. Each antibody was then screened in vitro by inhibition adherence assay of live PDP on chinook salmon embryo cells (CHSE-214). A lipoprotein, found to be involved in the adherence of the bacterium to epithelial cells and annotated as PDP_0080, was then selected. The recombinant protein was further investigated in fish vaccination and challenge experiments to assess its ability to protect sea bass, Dicentrarchus labrax, against PDP infection. Immunisation with PDP_0080 recombinant protein elicited high specific antibody titres. Furthermore, the survival rate of fish immunized with the 25 μg dose of protein was significantly higher compared to the control group. The results of the study suggest that the PDP_0080 protein could be a promising candidate for the design of a recombinant vaccine against pasteurellosis.

  1. Evaluation of Mdh1 protein as an antigenic candidate for a vaccine against candidiasis.

    Science.gov (United States)

    Shibasaki, Seiji; Aoki, Wataru; Nomura, Takashi; Karasaki, Miki; Sewaki, Tomomitsu; Ueda, Mitsuyoshi

    2014-01-01

    Candida albicans malate dehydrogenase (Mdh1p) has been screened by previous proteome studies as a candidate for a vaccine against candidiasis. In this study, recombinant Mdh1 protein with a His-tag was produced in Escherichia coli and evaluated as an immunogenic protein against candidiasis. Mdh1p was administrated to mice by two methods subcutaneous injection and intranasal administration before challenging them with a lethal dose of C. albicans. After vaccination of Mdh1p, antibody responses were observed. To evaluate the vaccination effect of Mdh1p, survival tests were performed after 35 d. Although all control mice died within 24 d or 25 d, 100% and 80% of mice survived with subcutaneous and intranasal administration, respectively. Therefore, our results indicate that, among C. albicans antigens examined thus far, Mdh1p is currently the most effective antigen for use as a vaccine for C. albicans.

  2. Select human anthrax protective antigen (PA) epitope-specific antibodies provide protection from lethal toxin challenge

    Science.gov (United States)

    Crowe, Sherry R.; Ash, Linda L.; Engler, Renata J. M.; Ballard, Jimmy D.; Harley, John B.; Farris, A. Darise; James, Judith A.

    2010-01-01

    Bacillus anthracis remains a serious bioterrorism concern, and the currently licensed vaccine remains an incomplete solution for population protection from inhalation anthrax and has been associated with concerns regarding efficacy and safety. Thus, understanding how to generate long lasting protective immunity with reduced immunizations or providing protection through post exposure immunotherapeutics are long sought goals. Through evaluation of a large military cohort, we characterized the levels of antibodies against protective antigen and found that over half of anthrax vaccinees had low levels of in vitro toxin neutralization capacity in their sera. Using solid phase epitope mapping and confirmatory assays, we identified several neutralization-associated humoral epitopes and demonstrated that select anti-peptide responses mediated protection in vitro. Finally, passively transferred antibodies specific for select epitopes provided protection in an in vivo lethal toxin mouse model. Identification of these antigenic regions has important implications for vaccine design and the development of directed immunotherapeutics. PMID:20533877

  3. 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

    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...volunteers who received live attenuated Shigella flexneri 2a vaccines. Subjects ingested a single oral dose of 107 , 108 or 109 CFU of S. flexneri 2a with

  4. Identification of vaccine candidate antigens of Staphylococcus pseudintermedius by whole proteome characterization and serological proteomic analyses.

    Science.gov (United States)

    Couto, Natacha; Martins, Joana; Lourenço, Ana Mafalda; Pomba, Constança; Varela Coelho, Ana

    2016-02-05

    The recent emergence of methicillin-resistant Staphylococcus pseudintermedius (MRSP) has complicated considerably the treatment of infections caused by these bacteria. Therefore new treatment strategies are urgently needed, namely through the development of vaccines towards the control of bacterial infections. Our study describes an extensive characterization of the proteome of S. pseudintermedius through a 2-DE MALDI-TOF/TOF approach, followed by SERological Proteome Analysis (SERPA) to identify potential vaccine candidate antigens. We were able to identify 361 unique proteins, of which 39 are surface proteins. In order to assess the immunogenic potential of S. pseudintermedius proteins, a Western blot analysis of two-dimensional gels was carried out with serum from healthy dogs, dogs with atopic dermatitis infected and not infected with S. pseudintermedius. Only immunogenic areas detected by ≥ 50% of the dogs with atopic dermatitis infected with S. pseudintermedius sera and by proteins could induce hypersensitivity. We were able to identify 13 unique proteins after in-gel digestion of selected protein gel spots, with 4 antigenic proteins showing promising features for vaccine development. No specific antibodies were identified in the dogs with atopic dermatitis not infected with S. pseudintermedius sera that could contribute to prevention of infection. The SERPA approach employed in this study revealed novel candidate therapeutic targets for the control of S. pseudintermedius infections.

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

    Directory of Open Access Journals (Sweden)

    Ratna eGurung

    2014-07-01

    Full Text Available Control of Johne’s disease, caused by Mycobacterium avium subspecies paratuberculosis (MAP in ruminants using commercially available vaccine reduces production losses, mortality, faecal 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.

  6. 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

  7. 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.

  8. Evaluation of the humoral immune response to human leukocyte antigens in Brazilian renal transplant candidates.

    Directory of Open Access Journals (Sweden)

    Patricia Keiko Saito

    Full Text Available Pre-transplant sensitization to human leukocyte antigens (HLA is a risk factor for graft failure. Studies of the immunological profile related to anti-HLA antibodies in Brazilian renal transplant candidates are few. In this study, we evaluated the humoral immune response to HLA antigens in 269 renal transplant candidates, in Paraná State, Brazil. The HLA typing was performed by the polymerase chain reaction sequence-specific oligonucleotide method (PCR-SSO combined with Luminex technology, using an SSO-LABType commercial kit (One Lambda, Inc., Canoga Park, CA, USA. The percentages of panel-reactive antibodies (PRA and the specificity of anti-HLA antibodies were determined using the LS1PRA and LS2PRA commercial kits (One Lambda, Inc.. The PRA-positive group consisted of 182 (67.7% patients, and the PRA-negative group of 87 (32.3% patients. The two groups differed significantly only with respect to gender. Females were the most sensitized. Among the 182 patients with PRA- positive, 62 (34.1% were positive for class I and negative for class II, 39 (21.4% were negative for class I and positive for class II, and 81 (44.5% were positive for both classes I and II. The HLA-A*02, A*24, A*01, B*44, B*35, B*15, DRB1*11, DRB1*04 and DRB1*03 allele groups were the most frequent. The specificities of anti-HLA antibodies were more frequent: A34, B57, Cw15, Cw16, DR51, DQ8 and DP14. This study documented the profile of anti-HLA antibodies in patients with chronic renal failure who were on waiting lists for an organ in Paraná, and found high sensitization to HLA antigens in the samples.

  9. Evaluation of the humoral immune response to human leukocyte antigens in Brazilian renal transplant candidates.

    Science.gov (United States)

    Saito, Patricia Keiko; Yamakawa, Roger Haruki; Aparecida, Erica Pereira; da Silva Júnior, Waldir Verissimo; Borelli, Sueli Donizete

    2014-01-01

    Pre-transplant sensitization to human leukocyte antigens (HLA) is a risk factor for graft failure. Studies of the immunological profile related to anti-HLA antibodies in Brazilian renal transplant candidates are few. In this study, we evaluated the humoral immune response to HLA antigens in 269 renal transplant candidates, in Paraná State, Brazil. The HLA typing was performed by the polymerase chain reaction sequence-specific oligonucleotide method (PCR-SSO) combined with Luminex technology, using an SSO-LABType commercial kit (One Lambda, Inc., Canoga Park, CA, USA). The percentages of panel-reactive antibodies (PRA) and the specificity of anti-HLA antibodies were determined using the LS1PRA and LS2PRA commercial kits (One Lambda, Inc.). The PRA-positive group consisted of 182 (67.7%) patients, and the PRA-negative group of 87 (32.3%) patients. The two groups differed significantly only with respect to gender. Females were the most sensitized. Among the 182 patients with PRA- positive, 62 (34.1%) were positive for class I and negative for class II, 39 (21.4%) were negative for class I and positive for class II, and 81 (44.5%) were positive for both classes I and II. The HLA-A*02, A*24, A*01, B*44, B*35, B*15, DRB1*11, DRB1*04 and DRB1*03 allele groups were the most frequent. The specificities of anti-HLA antibodies were more frequent: A34, B57, Cw15, Cw16, DR51, DQ8 and DP14. This study documented the profile of anti-HLA antibodies in patients with chronic renal failure who were on waiting lists for an organ in Paraná, and found high sensitization to HLA antigens in the samples.

  10. Immunization of Mice with Anthrax Protective Antigen Limits Cardiotoxicity but Not Hepatotoxicity Following Lethal Toxin Challenge.

    Science.gov (United States)

    Devera, T Scott; Prusator, Dawn K; Joshi, Sunil K; Ballard, Jimmy D; Lang, Mark L

    2015-06-25

    Protective immunity against anthrax is inferred from measurement of vaccine antigen-specific neutralizing antibody titers in serum samples. In animal models, in vivo challenges with toxin and/or spores can also be performed. However, neither of these approaches considers toxin-induced damage to specific organ systems. It is therefore important to determine to what extent anthrax vaccines and existing or candidate adjuvants can provide organ-specific protection against intoxication. We therefore compared the ability of Alum, CpG DNA and the CD1d ligand α-galactosylceramide (αGC) to enhance protective antigen-specific antibody titers, to protect mice against challenge with lethal toxin, and to block cardiotoxicity and hepatotoxicity. By measurement of serum cardiac Troponin I (cTnI), and hepatic alanine aminotransferase (ALT), and aspartate aminotransferase (AST), it was apparent that neither vaccine modality prevented hepatic intoxication, despite high Ab titers and ultimate survival of the subject. In contrast, cardiotoxicity was greatly diminished by prior immunization. This shows that a vaccine that confers survival following toxin exposure may still have an associated morbidity. We propose that organ-specific intoxication should be monitored routinely during research into new vaccine modalities.

  11. Synthetic Long Peptide Derived from Mycobacterium tuberculosis Latency Antigen Rv1733c Protects against Tuberculosis.

    Science.gov (United States)

    Coppola, Mariateresa; van den Eeden, Susan J F; Wilson, Louis; Franken, Kees L M C; Ottenhoff, Tom H M; Geluk, Annemieke

    2015-09-01

    Responsible for 9 million new cases of active disease and nearly 2 million deaths each year, tuberculosis (TB) remains a global health threat of overwhelming dimensions. Mycobacterium bovis BCG, the only licensed vaccine available, fails to confer lifelong protection and to prevent reactivation of latent infection. Although 15 new vaccine candidates are now in clinical trials, an effective vaccine against TB remains elusive, and new strategies for vaccination are vital. BCG vaccination fails to induce immunity against Mycobacterium tuberculosis latency antigens. Synthetic long peptides (SLPs) combined with adjuvants have been studied mostly for therapeutic cancer vaccines, yet not for TB, and proved to induce efficient antitumor immunity. This study investigated an SLP derived from Rv1733c, a major M. tuberculosis latency antigen which is highly expressed by "dormant" M. tuberculosis and well recognized by T cells from latently M. tuberculosis-infected individuals. In order to assess its in vivo immunogenicity and protective capacity, Rv1733c SLP in CpG was administered to HLA-DR3 transgenic mice. Immunization with Rv1733c SLP elicited gamma interferon-positive/tumor necrosis factor-positive (IFN-γ(+)/TNF(+)) and IFN-γ(+) CD4(+) T cells and Rv1733c-specific antibodies and led to a significant reduction in the bacterial load in the lungs of M. tuberculosis-challenged mice. This was observed both in a pre- and in a post-M. tuberculosis challenge setting. Moreover, Rv1733c SLP immunization significantly boosted the protective efficacy of BCG, demonstrating the potential of M. tuberculosis latency antigens to improve BCG efficacy. These data suggest a promising role for M. tuberculosis latency antigen Rv1733c-derived SLPs as a novel TB vaccine approach, both in a prophylactic and in a postinfection setting.

  12. Dendritic Cell Targeting of Bacillus anthracis Protective Antigen Expressed by Lactobacillus acidophilus Protects Mice from Lethal Challenge

    Science.gov (United States)

    2008-10-28

    Dendritic cell targeting of Bacillus anthracis protective antigen expressed by Lactobacillus acidophilus protects mice from lethal challenge M...lethal chal- lenge. A vaccine strategy was established by using Lactobacillus acidophilus to deliver Bacillus anthracis protective antigen (PA) via...include species of Lactobacillus , Lactococcus, Leuconostoc, Pedio- coccus, and Streptococcus. It is widely accepted that Lactobacillus species play a

  13. Protective antibody titres and antigenic competition in multivalent Dichelobacter nodosus fimbrial vaccines using characterised rDNA antigens.

    Science.gov (United States)

    Raadsma, H W; O'Meara, T J; Egerton, J R; Lehrbach, P R; Schwartzkoff, C L

    1994-03-01

    The relationship between K-agglutination antibody titres and protection against experimental challenge with Dichelobacter nodosus, the effect of increasing the number of D. nodosus fimbrial antigens, and the importance of the nature of additional antigens in multivalent vaccines on antibody response and protection against experimental challenge with D. nodosus were examined in Merino sheep. A total of 204 Merino sheep were allocated to one of 12 groups, and vaccinated with preparations containing a variable number of rDNA D. nodosus fimbrial antigens. The most complex vaccine contained ten fimbrial antigens from all major D. nodosus serogroups, while the least complex contained a single fimbrial antigen. In addition to D. nodosus fimbrial antigens, other bacterial rDNA fimbrial antigens (Moraxella bovis Da12d and Escherichia coli K99), and bovine serum albumin (BSA) were used in some vaccines. Antibody titres to fimbrial antigens and BSA were measured by agglutination and ELISA tests, respectively. Antibody titres were determined on five occasions (Weeks 0, 3, 6, 8, and 11 after primary vaccination). All sheep were exposed to an experimental challenge with virulent isolates of D. nodosus from either serogroup A or B, 8 weeks after primary vaccination. For D. nodosus K-agglutinating antibody titres, a strong negative correlation between antibody titre and footrot lesion score was observed. This relationship was influenced by the virulence of the challenge strain. Increasing the number of fimbrial antigens in experimental rDNA D. nodosus fimbrial vaccines resulted in a linear decrease in K-agglutinating antibody titres to individual D. nodosus serogroups. Similarly, a linear decrease in protection to challenge with homologous serogroups was observed as the number of D. nodosus fimbrial antigens represented in the vaccine increased. The reduction in antibody titres in multicomponent vaccines is thought to be due to antigenic competition. The level of competition

  14. Identification by genomic immunization of a pool of DNA vaccine candidates that confer protective immunity in mice against Neisseria meningitidis serogroup B.

    Science.gov (United States)

    Yero, Daniel; Pajón, Rolando; Pérez, Yusleydis; Fariñas, Mildrey; Cobas, Karem; Diaz, Daiyana; Solis, Rosa L; Acosta, Armando; Brookes, Charlotte; Taylor, Stephen; Gorringe, Andrew

    2007-07-09

    We have shown previously that expression library immunization is viable alternative approach to induce protective immunity against Neisseria meningitidis serogroup B. In this study we report that few rounds of library screening allow identification of protective pools of defined antigens. A previously reported protective meningococcal library (L8, with 600 clones) was screened and two sub-libraries of 95 clones each were selected based on the induction of bactericidal and protective antibodies in BALB/c mice. After sequence analysis of each clone within these sub-libraries, we identified a pool of 20 individual antigens that induced protective immune responses in mice against N. meningitidis infection, and the observed protection was associated with the induction of bactericidal antibodies. Our studies demonstrate for the first time that ELI combined with sequence analysis is a powerful and efficient tool for identification of candidate antigens for use in a meningococcal vaccine.

  15. Excretory-secretory antigens: a suitable candidate for immunization against ocular toxoplasmosis in a murine model.

    Science.gov (United States)

    Norouzpour Deilami, Kiumars; Daryani, Ahmad; Ahmadpour, Ehsan; Sharif, Mehdi; Dadimoghaddam, Yousef; Sarvi, Shahabeddin; Alizadeh, Ahad

    2014-12-01

    Toxoplasmosis, responsible for ocular impairment, is caused by Toxoplasma gondii. We investigated the effect of Toxoplasma excretory-secretory antigens (ESA) on parasite load and distribution in the eye tissue of a murine model. Case and control groups were immunized with ESA and PBS, respectively. Two weeks after the second immunization, the mice were challenged intraperitoneally with virulent RH strain of Toxoplasma; eye tissue samples of both groups were collected daily (days 1, 2, 3, and the last day before death). Parasite load was determined using real-time quantitative PCR targeted at the B1 gene. Compared to the control group, infected mice that received ESA vaccine presented a considerable decrease in parasite load in the eye tissue, demonstrating the effect of ESA on parasite load and distribution. Diminution of parasite load in mouse eye tissue indicated that ESA might help control disease-related complications and could be a valuable immunization candidate against ocular toxoplasmosis.

  16. Subdominant Outer Membrane Antigens in Anaplasma marginale: Conservation, Antigenicity, and Protective Capacity Using Recombinant Protein.

    Directory of Open Access Journals (Sweden)

    Deirdre R Ducken

    Full Text Available Anaplasma marginale is a tick-borne rickettsial pathogen of cattle with a worldwide distribution. Currently a safe and efficacious vaccine is unavailable. Outer membrane protein (OMP extracts or a defined surface protein complex reproducibly induce protective immunity. However, there are several knowledge gaps limiting progress in vaccine development. First, are these OMPs conserved among the diversity of A. marginale strains circulating in endemic regions? Second, are the most highly conserved outer membrane proteins in the immunogens recognized by immunized and protected animals? Lastly, can this subset of OMPs recognized by antibody from protected vaccinates and conserved among strains recapitulate the protection of outer membrane vaccines? To address the first goal, genes encoding OMPs AM202, AM368, AM854, AM936, AM1041, and AM1096, major subdominant components of the outer membrane, were cloned and sequenced from geographically diverse strains and isolates. AM202, AM936, AM854, and AM1096 share 99.9 to 100% amino acid identity. AM1041 has 97.1 to 100% and AM368 has 98.3 to 99.9% amino acid identity. While all four of the most highly conserved OMPs were recognized by IgG from animals immunized with outer membranes, linked surface protein complexes, or unlinked surface protein complexes and shown to be protected from challenge, the highest titers and consistent recognition among vaccinates were to AM854 and AM936. Consequently, animals were immunized with recombinant AM854 and AM936 and challenged. Recombinant vaccinates and purified outer membrane vaccinates had similar IgG and IgG2 responses to both proteins. However, the recombinant vaccinates developed higher bacteremia after challenge as compared to adjuvant-only controls and outer membrane vaccinates. These results provide the first evidence that vaccination with specific antigens may exacerbate disease. Progressing from the protective capacity of outer membrane formulations to

  17. Subdominant Outer Membrane Antigens in Anaplasma marginale: Conservation, Antigenicity, and Protective Capacity Using Recombinant Protein.

    Science.gov (United States)

    Ducken, Deirdre R; Brown, Wendy C; Alperin, Debra C; Brayton, Kelly A; Reif, Kathryn E; Turse, Joshua E; Palmer, Guy H; Noh, Susan M

    2015-01-01

    Anaplasma marginale is a tick-borne rickettsial pathogen of cattle with a worldwide distribution. Currently a safe and efficacious vaccine is unavailable. Outer membrane protein (OMP) extracts or a defined surface protein complex reproducibly induce protective immunity. However, there are several knowledge gaps limiting progress in vaccine development. First, are these OMPs conserved among the diversity of A. marginale strains circulating in endemic regions? Second, are the most highly conserved outer membrane proteins in the immunogens recognized by immunized and protected animals? Lastly, can this subset of OMPs recognized by antibody from protected vaccinates and conserved among strains recapitulate the protection of outer membrane vaccines? To address the first goal, genes encoding OMPs AM202, AM368, AM854, AM936, AM1041, and AM1096, major subdominant components of the outer membrane, were cloned and sequenced from geographically diverse strains and isolates. AM202, AM936, AM854, and AM1096 share 99.9 to 100% amino acid identity. AM1041 has 97.1 to 100% and AM368 has 98.3 to 99.9% amino acid identity. While all four of the most highly conserved OMPs were recognized by IgG from animals immunized with outer membranes, linked surface protein complexes, or unlinked surface protein complexes and shown to be protected from challenge, the highest titers and consistent recognition among vaccinates were to AM854 and AM936. Consequently, animals were immunized with recombinant AM854 and AM936 and challenged. Recombinant vaccinates and purified outer membrane vaccinates had similar IgG and IgG2 responses to both proteins. However, the recombinant vaccinates developed higher bacteremia after challenge as compared to adjuvant-only controls and outer membrane vaccinates. These results provide the first evidence that vaccination with specific antigens may exacerbate disease. Progressing from the protective capacity of outer membrane formulations to recombinant vaccines

  18. Expression and Purification of the Bacillus anthracis Protective Antigen Receptor-binding Domain

    Institute of Scientific and Technical Information of China (English)

    葛猛; 徐俊杰; 李冰; 董大勇; 宋小红; 郭强; 赵剑; 陈薇

    2004-01-01

    The aim of this study is to express the receptor-binding domain of Bacillus anthracis protective antigen in E. coli. Signal sequence of the outer membrane protein A (OmpA) of E. coli was attached to the 5' end of the gene encoding protective antigen receptor-binding domain (the 4th domain of PA, PALM). The plasmid carrying the fusion gene was then transformed into E. coli and induced to express recombinant PAlM by IFFG. The recombinant protein was purified by chromatography and then identified by N-terrainal sequencing and Western blot. The recombinant protein, about 10% of the total bacterial protein in volume, was secreted to the periplasmic space of the cell. After a purification procedure including ionexchange chromatography and gel filtration, about 10 mg of homogenous recombinant PAD4 was obtained from 1 L culture. Data from N-terminal sequencing suggested that the amino acid sequence of recombinant PAD4 was identical with its natural counterpart. And the result of Western blot showed the recombinant protein could bind with anti-PA serum from rabbit. High level secreted expression of PAD4 was obtained in E. coli. The results reported here are parts of a continuing research to evaluate PAD4 as a potential drug for anthrax therapy or a candidate of new vaccine.

  19. 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...

  20. Discovery of GAMA, a Plasmodium falciparum merozoite micronemal protein, as a novel blood-stage vaccine candidate antigen.

    Science.gov (United States)

    Arumugam, Thangavelu U; Takeo, Satoru; Yamasaki, Tsutomu; Thonkukiatkul, Amporn; Miura, Kazutoyo; Otsuki, Hitoshi; Zhou, Hong; Long, Carole A; Sattabongkot, Jetsumon; Thompson, Jennifer; Wilson, Danny W; Beeson, James G; Healer, Julie; Crabb, Brendan S; Cowman, Alan F; Torii, Motomi; Tsuboi, Takafumi

    2011-11-01

    One of the solutions for reducing the global mortality and morbidity due to malaria is multivalent vaccines comprising antigens of several life cycle stages of the malarial parasite. Hence, there is a need for supplementing the current set of malaria vaccine candidate antigens. Here, we aimed to characterize glycosylphosphatidylinositol (GPI)-anchored micronemal antigen (GAMA) encoded by the PF08_0008 gene in Plasmodium falciparum. Antibodies were raised against recombinant GAMA synthesized by using a wheat germ cell-free system. Immunoelectron microscopy demonstrated for the first time that GAMA is a microneme protein of the merozoite. Erythrocyte binding assays revealed that GAMA possesses an erythrocyte binding epitope in the C-terminal region and it binds a nonsialylated protein receptor on human erythrocytes. Growth inhibition assays revealed that anti-GAMA antibodies can inhibit P. falciparum invasion in a dose-dependent manner and GAMA plays a role in the sialic acid (SA)-independent invasion pathway. Anti-GAMA antibodies in combination with anti-erythrocyte binding antigen 175 exhibited a significantly higher level of invasion inhibition, supporting the rationale that targeting of both SA-dependent and SA-independent ligands/pathways is better than targeting either of them alone. Human sera collected from areas of malaria endemicity in Mali and Thailand recognized GAMA. Since GAMA in P. falciparum is refractory to gene knockout attempts, it is essential to parasite invasion. Overall, our study indicates that GAMA is a novel blood-stage vaccine candidate antigen.

  1. A study of recombinant protective H. Pylori antigens

    Institute of Scientific and Technical Information of China (English)

    Zheng Jiang; Xiao-Hong Tao; Ai-Long Huang; Pi-Long Wang

    2002-01-01

    AIM: To construct a recombinant vector which can express Mr 26 000 outer membrane protein (OMP) from Helicobacter pylori (Hp), and to obtain the vaccine protecting against Hp infection and a diagnostic reagent kit quickly detecting Hp infection.METHODS: The gene encoding the structural Mr 26000 outermembrane protein of Hp was amplified from Hpchromosomal DNA by PCR, and inserted in the prokaryoticexpression vector pET32a ( + ), which was transformed intothe Topl0 E. coli strain. Recombinant vector was selected,identified and transformed into BL-21(DE3) E. coli strain.The recombinant fusion proteins were expressed. Theantigenicity of recombinant protein was studied by ELISA orimmunoblotting and immunized Balb/c mice.RESULTS: The gene of Mr 26 000 OMP was amplified to be594 base pairs, 1.1% of the cloned genes was mutated and1.51% of amino acid residues was changed, but there washomogeneity between them. The recombinant fusion proteinencoded objective polypeptides of 198 amino acid residues,corresponding to calculated molecular masses of Mr 26000.The level of soluble expression products was about 38.96 %of the total cell protein. After purification by Ni-NTA agaroseresin columniation, the purity of objective protein becameabout 90 %. The EESA results showed that recombinantfusion protein could be recognized by patient serum infectedwith Hp and rabbit serum immunized with the recombinantprotein. Furthermore, Balb/ c mice immunized with therecombinant proteln were protected against H. pyloriinfection.CONCLUSION: Mr 26 000 OMP may be a candidate vaccinepreventing Hp infection.

  2. Ether lipid vesicle-based antigens impart protection against experimental listeriosis

    Directory of Open Access Journals (Sweden)

    Ansari MA

    2012-06-01

    Full Text Available Mairaj Ahmed Ansari,1 Swaleha Zubair,2 Saba Tufail,1 Ejaj Ahmad,1 Mohsin Raza Khan,1 Zainuddin Quadri,1 Mohammad Owais,11Interdisciplinary Biotechnology Unit, 2Women's College, Aligarh Muslim University, Aligarh, UP, IndiaBackground: Incidence of food-borne infections from Listeria monocytogenes, a parasite that has adapted intracellular residence to avoid antibody onslaught, has increased dramatically in the past few years. The apparent lack of an effective vaccine that is capable of evoking the desired cytotoxic T cell response to obliterate this intracellular pathogen has encouraged the investigation of alternate prophylactic strategies. It should also be noted that Archaebacteria (Archae lipid-based adjuvants enhance the efficacy of subunit vaccines. In the present study, the adjuvant properties of archaeosomes (liposomes prepared from total polar lipids of archaebacteria, Halobacterium salinarum combined with immunogenic culture supernatant antigens of L. monocytogenes have been exploited in designing a vaccine candidate against experimental listeriosis in murine model.Methods: Archaeosome-entrapped secretory protein antigens (SAgs of L. monocytogenes were evaluated for their immunological responses and tendency to deplete bacterial burden in BALB/c mice challenged with sublethal listerial infection. Various immunological studies involving cytokine profiling, lymphocyte proliferation assay, detection of various surface markers (by flowcytometric analysis, and antibody isotypes (by enzyme-linked immunosorbent assay were used for establishing the vaccine potential of archaeosome-entrapped secretory proteins.Results: Immunization schedule involving archaeosome-encapsulated SAgs resulted in upregulation of Th1 cytokine production along with boosted memory in BALB/c mice. It also showed protective effect by reducing listerial burden in various vital organs (liver and spleen of the infected mice. However, the soluble form of the antigens (SAgs

  3. Development of influenza A(H7N9) candidate vaccine viruses with improved hemagglutinin antigen yield in eggs

    Science.gov (United States)

    Ridenour, Callie; Johnson, Adam; Winne, Emily; Hossain, Jaber; Mateu-Petit, Guaniri; Balish, Amanda; Santana, Wanda; Kim, Taejoong; Davis, Charles; Cox, Nancy J; Barr, John R; Donis, Ruben O; Villanueva, Julie; Williams, Tracie L; Chen, Li-Mei

    2015-01-01

    Background The emergence of avian influenza A(H7N9) virus in poultry causing zoonotic human infections was reported on March 31, 2013. Development of A(H7N9) candidate vaccine viruses (CVV) for pandemic preparedness purposes was initiated without delay. Candidate vaccine viruses were derived by reverse genetics using the internal genes of A/Puerto/Rico/8/34 (PR8). The resulting A(H7N9) CVVs needed improvement because they had titers and antigen yields that were suboptimal for vaccine manufacturing in eggs, especially in a pandemic situation. Methods Two CVVs derived by reverse genetics were serially passaged in embryonated eggs to improve the hemagglutinin (HA) antigen yield. The total viral protein and HA antigen yields of six egg-passaged CVVs were determined by the BCA assay and isotope dilution mass spectrometry (IDMS) analysis, respectively. CVVs were antigenically characterized by hemagglutination inhibition (HI) assays with ferret antisera. Results Improvement of total viral protein yield was observed for the six egg-passaged CVVs; HA quantification by IDMS indicated approximately a twofold increase in yield of several egg-passaged viruses as compared to that of the parental CVV. Several different amino acid substitutions were identified in the HA of all viruses after serial passage. However, HI tests indicated that the antigenic properties of two CVVs remained unchanged. Conclusions If influenza A(H7N9) viruses were to acquire sustained human-to-human transmissibility, the improved HA yield of the egg-passaged CVVs generated in this study could expedite vaccine manufacturing for pandemic mitigation. PMID:25962412

  4. Studies on the protective efficacy of freeze thawed promastigote antigen of Leishmania donovani along with various adjuvants against visceral leishmaniasis infection in mice.

    Science.gov (United States)

    Thakur, Ankita; Kaur, Harpreet; Kaur, Sukhbir

    2015-09-01

    Visceral leishmaniasis (VL) caused by Leishmania donovani persists as a major public health issue in tropical and subtropical areas of the world. Current treatment of this disease relies on use of drugs. It is doubtful that chemotherapy can alone eradicate the disease, so there is a need for an effective vaccine. Killed antigen candidates remain a good prospect considering their ease of formulation, stability, low cost and safety. To enhance the efficacy of killed vaccines suitable adjuvant and delivery system are needed. Therefore, the current study was conducted to determine the protective efficacy of freeze-thawed L. donovani antigen in combination with different adjuvants against experimental infection of VL. For this, BALB/c mice were immunized thrice at an interval of two weeks. Challenge infection was given two weeks after last immunization. Mice were sacrificed after last immunization and on different post challenge/infection days. Immunized mice showed significant reduction in parasite burden, enhanced DTH responses with increased levels of Th1 cytokines and lower levels of Th2 cytokines, thus indicating the development of a protective Th1 response. Maximum protection was achieved with liposome encapsulated freeze thawed promastigote (FTP) antigen of L. donovani and it was followed by group immunized with FTP+MPL-A, FTP+saponin, FTP+alum and FTP antigen (alone). The present study highlights greater efficacy of freeze thawed promastigote antigen as a potential vaccine candidate along with effective adjuvant formulations against experimental VL infection.

  5. Characterization of a Partially Protective B-cell Epitope within the 62 kDa Antigen of Schistosoma japonicun

    Institute of Scientific and Technical Information of China (English)

    Lei ZHANG; Xue YANG; Yanfen YANG; Jiaqing ZHAO; Jianghua YANG; Feng LIU; Zhaosong ZHANG; Guanling WU; Chuan SU

    2007-01-01

    Approximately 200 million people worldwide currently suffer from schistosomiasis, one of the most important human parasitic diseases. Although an established infection can be treated with anthelminthics and praziquantel, vaccination would be the ideal method for integral control of schistosomiasis. Schistosoma mansoni IrⅤ-5, recommended as a vaccine candidate by the World Health Organization/Special Programme for Research and Training in Tropical Diseases, produced high protection in animal models. We therefore focused on its homolog, the Schistosoma japonicum 62 kDa antigen, and analyzed it using B cell/antibodyrelated databases and analysis tools for the prediction of B-cell epitopes. Epitope B3 was selected for further investigation. Experiments using a murine model indicated that mice immunized with B3 resulted in lymphocytes proliferation and produced high levels of specific immunoglobulin G and G1, but did not produce impressive cytokines. The vaccination showed partial protective immunity, measured by worm burden and anti-fecundity immunity against S. japonicum. These results indicated that the epitope B3 from S. japonicum 62-kDa antigen might act as a candidate immunogen for future epitope vaccine investigation.

  6. An efficient fusion protein system for expression ofBacillus anthracis protective antigen as immunogenic and diagnostic antigen

    Institute of Scientific and Technical Information of China (English)

    Vahid Bagheri; Hossein Motamedi; Masoud Reza Seifiabad Shapouri

    2010-01-01

    Objective:To produce high quantities of recombinant protective antigen (rPA) for human vaccine and diagnosis.Methods: ThePAgene was amplified byPCR with pXO1 plasmid as template. ThePCR product was cloned into pMAL-c2X vector using theBamHI andSalI restriction enzymes. The recombinant plasmid was transformed intoEscherichia coliDH5α strain and then screened for transformation. The expression of protective antigen was analyzed bySDS-PAGE and Western blotting after isopropyl β-D-thiogalactopyranoside(IPTG) induction.Results:The full-length PA gene (2.2kb) was cloned into pMAL vector system. The recombinant vector was confirmed by restriction enzyme andPCRanalysis. The expression of cytoplasmic maltose-binding protein-protective (MBP-P) antigen fusion protein was detected bySDS-PAGE and Western blotting, and obtained a125 kDa protein band, which was similar to expected size of fusion protein.Conclusions: This expression system can be used in the high production of rPA. After purification and immunization studies, the purified rPA may be used in the development of the human recombinant anthrax vaccine and also in diagnosis of anthrax disease.

  7. Comprehensive Antigen Screening Identifies Moraxella catarrhalis Proteins That Induce Protection in a Mouse Pulmonary Clearance Model

    NARCIS (Netherlands)

    M. Smidt (Margarita); P. Bättig (Patrick); S.J.C. Verhaegh (Suzanne); A. Niebisch (Axel); M. Hanner (Markus); S. Selak (Sanja); W. Schüler (Wolfgang); E. Morfeldt (Eva); C. Hellberg (Christel); E. Nagy (Eszter); U. Lundberg (Urban); J.P. Hays (John); A. Meinke (Andreas); B. Henriques-Normark (Birgitta)

    2013-01-01

    textabstractMoraxella catarrhalis is one of the three most common causative bacterial pathogens of otitis media, however no effective vaccine against M. catarrhalis has been developed so far. To identify M. catarrhalis vaccine candidate antigens, we used carefully selected sera from children with ot

  8. 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 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 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. 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.

  9. Expression, purification and characterization of the cancer-germline antigen GAGE12I: a candidate for cancer immunotherapy

    DEFF Research Database (Denmark)

    Gjerstorff, Morten F; Besir, Hüseyin; Larsen, Martin R

    2010-01-01

    for immunotherapy and candidates for cancer vaccines. Recombinant proteins may be superior to peptides as immunogens, since they have the potential to prime both CD4(+) and CD8(+) T cells and are not dependent on patient HLA-type. We have developed a method for production of highly pure recombinant GAGE12I......GAGE cancer-germline antigens are frequently expressed in a broad range of different cancers, while their expression in normal tissues is limited to the germ cells of the immune privileged organs, testis and ovary. GAGE proteins are immunogenic in humans, which make them promising targets...... filtration and formaldehyde cross-linking indicated that GAGE12I forms tetramers. The purified recombinant GAGE12I represents a candidate molecule for vaccination of cancer patients and will form the basis for further structural analysis of GAGE proteins....

  10. Protection against Taenia pisiformis larval infection induced by a recombinant oncosphere antigen vaccine.

    Science.gov (United States)

    Chen, L; Yang, D Y; Xie, Y; Nong, X; Huang, X; Fu, Y; Gu, X B; Wang, S X; Peng, X R; Yang, G Y

    2014-02-13

    Taenia pisiformis larvae cause significant health problems to rabbits. At present, it is not known whether the recombinant antigen from the T. pisiformis oncosphere is able to confer protective immunity against T. pisiformis larval infection. The full-length cDNA was cloned into a pET32a (+) vector, and the recombinant protein was then expressed in BL21 (DE3) cells. Vaccination with the purified rTpUbc2 coupled with QuilA was carried out in New Zealand rabbits to evaluate the immunoprotective effect against T. pisiformis infection. The full-length open reading frame of the TpUbc2 gene was 444 bp, and encoded a 16.63-kDa protein. Finally, rTpUbc2 was used to evaluate the ability to induce immunoprotective responses in rabbits. A 79.3-90.8% reduction (P 0.05). Our data support the use of rTpUbc2 as a potential candidate to develop a vaccine against T. pisiformis larvae.

  11. Discovering naturally processed antigenic determinants that confer protective T cell immunity

    DEFF Research Database (Denmark)

    Gilchuk, Pavlo; Spencer, Charles T; Conant, Stephanie B;

    2013-01-01

    CD8+ T cells (TCD8) confer protective immunity against many infectious diseases, suggesting that microbial TCD8 determinants are promising vaccine targets. Nevertheless, current T cell antigen identification approaches do not discern which epitopes drive protective immunity during active infectio...

  12. Recombinant Forms of Leishmania amazonensis Excreted/Secreted Promastigote Surface Antigen (PSA Induce Protective Immune Responses in Dogs.

    Directory of Open Access Journals (Sweden)

    Elodie Petitdidier

    2016-05-01

    Full Text Available Preventive vaccination is a highly promising strategy for interrupting leishmaniasis transmission that can, additionally, contribute to elimination. A vaccine formulation based on naturally excreted secreted (ES antigens was prepared from L. infantum promastigote culture supernatant. This vaccine achieved successful results in Phase III trials and was licensed and marketed as CaniLeish. We recently showed that newly identified ES promastigote surface antigen (PSA, from both viable promastigotes and axenically-grown amastigotes, represented the major constituent and the highly immunogenic antigen of L. infantum and L. amazonensis ES products. We report here that three immunizations with either the recombinant ES LaPSA-38S (rPSA or its carboxy terminal part LaPSA-12S (Cter-rPSA, combined with QA-21 as adjuvant, confer high levels of protection in naive L. infantum-infected Beagle dogs, as checked by bone marrow parasite absence in respectively 78.8% and 80% of vaccinated dogs at 6 months post-challenge. The parasite burden in infected vaccinated dogs was significantly reduced compared to placebo group, as measured by q-PCR. Moreover, our results reveal humoral and cellular immune response clear-cut differences between vaccinated and control dogs. An early increase in specific IgG2 antibodies was observed in rPSA/QA-21- and Cter-rPSA/QA-21-immunized dogs only. They were found functionally active in vitro and were highly correlated with vaccine protection. In vaccinated protected dogs, IFN-γ and NO productions, as well as anti-leishmanial macrophage activity, were increased. These data strongly suggest that ES PSA or its carboxy-terminal part, in recombinant forms, induce protection in a canine model of zoonotic visceral leishmaniasis by inducing a Th1-dominant immune response and an appropriate specific antibody response. These data suggest that they could be considered as important active components in vaccine candidates.

  13. Protective effect of antigen delivery using monoolein-based liposomes in experimental hematogenously disseminated candidiasis

    OpenAIRE

    Carneiro, Catarina; Correia, Alexandra; Lima, Tanea; Vilanova, Manuel; Pais, Célia; Gomes, Andreia; Real Oliveira, M. Elisabete C.D.; Sampaio, Paula

    2016-01-01

    We evaluated the potential of a liposomal antigen delivery system (ADS) containing Candida albicans cell wall surface proteins (CWSP) in mediating protection against systemic candidiasis. Treatment of bonemarrow- derived dendritic cells with CWSP-loaded dioctadecyldimethylammonium bromide:monoolein (DODAB:MO) liposomes enhanced and prolonged their activation comparatively to free antigen, indicating that liposome-entrapped CWSP were released more sustainable. Therefore, we immuniz...

  14. Genetic immunization elicits antigen-specific protective immune responses and decreases disease severity in Trypanosoma cruzi infection.

    Science.gov (United States)

    Garg, Nisha; Tarleton, Rick L

    2002-10-01

    Immunity to Trypanosoma cruzi requires elicitation of humoral and cell-mediated immune responses to extracellular trypomastigotes and intracellular amastigotes. In this study, the effectiveness of the T. cruzi trans-sialidase family (ts) genes ASP-1, ASP-2, and TSA-1 as genetic vaccines was assessed. Immunization of mice with plasmids encoding ASP-1, ASP-2, or TSA-1 elicited poor antigen-specific cytotoxic-T-lymphocyte (CTL) activity and T. cruzi-specific antibody responses. Codelivery of interleukin-12 and granulocyte-macrophage colony-stimulating factor plasmids with antigen-encoding plasmids resulted in a substantial increase in CTL activity and antibody production and in increased resistance to T. cruzi infection. In pooled results from two to four experiments, 30 to 60% of mice immunized with antigen-encoding plasmids and 60 to 80% of mice immunized with antigen-encoding plasmids plus cytokine adjuvants survived a lethal challenge with T. cruzi. In comparison, 90% of control mice injected with empty plasmid DNA died during the acute phase of infection. However, the pool of three ts genes provided no greater protection than the most effective single gene (ASP-2) either with or without coadministration of cytokine plasmids. Importantly, the extent of tissue parasitism, inflammation, and associated tissue damage in skeletal muscles during the chronic phase of T. cruzi infection in mice immunized with antigen-encoding plasmids plus cytokine adjuvants was remarkably reduced compared to mice immunized with only cytokine adjuvants or empty plasmid DNA. These results identify new vaccine candidates and establish some of the methodologies that might be needed to develop effective vaccine-mediated control of T. cruzi infection. In addition, this work provides the first evidence that prophylactic genetic immunization can prevent the development of Chagas' disease.

  15. A Chemically Synthesized Capture Agent Enables the Selective, Sensitive, and Robust Electrochemical Detection of Anthrax Protective Antigen

    Science.gov (United States)

    2014-08-01

    A Chemically Synthesized Capture Agent Enables the Selective, Sensitive, and Robust Electrochemical Detection of Anthrax Protective Antigen...A Chemically Synthesized Capture Agent Enables the Selective, Sensitive, and Robust Electrochemical Detection of Anthrax Protective Antigen...AND SUBTITLE A Chemically Synthesized Capture Agent Enables the Selective, Sensitive, and Robust Electrochemical Detection of Anthrax Protective

  16. KSAC, a defined Leishmania antigen, plus adjuvant protects against the virulence of L. major transmitted by its natural vector Phlebotomus duboscqi.

    Directory of Open Access Journals (Sweden)

    Regis Gomes

    Full Text Available BACKGROUND: Recombinant KSAC and L110f are promising Leishmania vaccine candidates. Both antigens formulated in stable emulsions (SE with the natural TLR4 agonist MPL® and L110f with the synthetic TLR4 agonist GLA in SE protected BALB/c mice against L. major infection following needle challenge. Considering the virulence of vector-transmitted Leishmania infections, we vaccinated BALB/c mice with either KSAC+GLA-SE or L110f+GLA-SE to assess protection against L. major transmitted via its vector Phlebotomus duboscqi. METHODS: Mice receiving the KSAC or L110f vaccines were challenged by needle or L. major-infected sand flies. Weekly disease progression and terminal parasite loads were determined. Immunological responses to KSAC, L110f, or soluble Leishmania antigen (SLA were assessed throughout vaccination, three and twelve weeks after immunization, and one week post-challenge. RESULTS: Following sand fly challenge, KSAC-vaccinated mice were protected while L110f-vaccinated animals showed partial protection. Protection correlated with the ability of SLA to induce IFN-γ-producing CD4(+CD62L(lowCCR7(low effector memory T cells pre- and post-sand fly challenge. CONCLUSIONS: This study demonstrates the protective efficacy of KSAC+GLA-SE against sand fly challenge; the importance of vector-transmitted challenge in evaluating vaccine candidates against Leishmania infection; and the necessity of a rapid potent Th1 response against Leishmania to attain true protection.

  17. 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

    subjects compared to positive participants, whereas immunoglobulin subclass distribution was similar. Memory B-cell response was moderately increased in T. trichiura negative individuals, although the difference was not significant. CONCLUSIONS: Future malaria vaccine development programs need to account......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...

  18. 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.

  19. Protective-antigen (PA) based anthrax vaccines confer protection against inhalation anthrax by precluding the establishment of a systemic infection.

    Science.gov (United States)

    Merkel, Tod J; Perera, Pin-Yu; Lee, Gloria M; Verma, Anita; Hiroi, Toyoko; Yokote, Hiroyuki; Waldmann, Thomas A; Perera, Liyanage P

    2013-09-01

    An intense effort has been launched to develop improved anthrax vaccines that confer rapid, long lasting protection preferably with an extended stability profile amenable for stockpiling. Protective antigen (PA)-based vaccines are most favored as immune responses directed against PA are singularly protective, although the actual protective mechanism remains to be unraveled. Herein we show that contrary to the prevailing view, an efficacious PA-based vaccine confers protection against inhalation anthrax by preventing the establishment of a toxin-releasing systemic infection. Equally importantly, antibodies measured by the in vitro lethal toxin neutralization activity assay (TNA) that is considered as a reliable correlate of protection, especially for PA protein-based vaccines adjuvanted with aluminum salts appear to be not absolutely essential for this protective immune response.

  20. THE SCHISTOSOMULA TEGUMENT ANTIGEN AS A POTENTIAL CANDIDATE FOR THE EARLY SEROLOGICAL DIAGNOSIS OF SCHISTOSOMIASIS MANSONI

    Directory of Open Access Journals (Sweden)

    Rafaella Grenfell

    2013-04-01

    Full Text Available If Schistosoma mansoni infection could be detected in its early stages, especially before the egg deposition in the host tissues, the development of severe pathologic lesions could be efficiently prevented. We therefore developed an indirect enzyme-linked immunosorbent assay based on the detection of specific IgG against schistosomula antigens (ELISA-SmTeg. The assay was applied in sera samples from non-infected and infected mice collected seven and 15 days post-infection. The results were compared to the number of adult worms obtained by perfusion of the murine hepatic system 50 days post-infection. The sensitivity and specificity of the ELISA-SmTeg were 100% (p = 0.0032 and 0.0048 respectively for seven and 15 days of infection with a cutoff value of 0.15 (p = 0.0002. Our findings show a novel low-cost serological assay using antigens which are easy to obtain, which was able to detect all the infected mice as early as seven days post-infection.

  1. Screening of 71 P. multocida proteins for protective efficacy in a fowl cholera infection model and characterization of the protective antigen PlpE.

    Directory of Open Access Journals (Sweden)

    Tamás Hatfaludi

    Full Text Available BACKGROUND: There is a strong need for a recombinant subunit vaccine against fowl cholera. We used a reverse vaccinology approach to identify putative secreted or cell surface associated P. multocida proteins that may represent potential vaccine candidate antigens. PRINCIPAL FINDINGS: A high-throughput cloning and expression protocol was used to express and purify 71 recombinant proteins for vaccine trials. Of the 71 proteins tested, only one, PlpE in denatured insoluble form, protected chickens against fowl cholera challenge. PlpE also elicited comparable levels of protection in mice. PlpE was localized by immunofluorescence to the bacterial cell surface, consistent with its ability to elicit a protective immune response. To explore the role of PlpE during infection and immunity, a plpE mutant was generated. The plpE mutant strain retained full virulence for mice. CONCLUSION: These studies show that PlpE is a surface exposed protein and was the only protein of 71 tested that was able to elicit a protective immune response. However, PlpE is not an essential virulence factor. This is the first report of a denatured recombinant protein stimulating protection against fowl cholera.

  2. Immunodominant antigens of Leishmania chagasi associated with protection against human visceral leishmaniasis.

    Directory of Open Access Journals (Sweden)

    Daniel R Abánades

    Full Text Available BACKGROUND: Protection and recovery from visceral leishmaniasis (VL have been associated with cell-mediated immune (CMI responses, whereas no protective role has been attributed to humoral responses against specific parasitic antigens. In this report, we compared carefully selected groups of individuals with distinct responses to Leishmania chagasi to explore antigen-recognizing IgG present in resistant individuals. METHODOLOGY AND PRINCIPAL FINDINGS: VL patients with negative delayed-type hypersensitivity (DTH were classified into the susceptible group. Individuals who had recovered from VL and converted to a DTH+ response, as well as asymptomatic infected individuals (DTH+, were categorized into the resistant group. Sera from these groups were used to detect antigens from L. chagasi by conventional and 2D Western blot assays. Despite an overall reduction in the reactivity of several proteins after DTH conversion, a specific group of proteins (approximately 110-130 kDa consistently reacted with sera from DTH converters. Other antigens that specifically reacted with sera from DTH+ individuals were isolated and tandem mass spectrometry followed by database query with the protein search engine MASCO were used to identify antigens. The serological properties of recombinant version of the selected antigens were tested by ELISA. Sera from asymptomatic infected people (DTH+ reacted more strongly with a mixture of selected recombinant antigens than with total soluble Leishmania antigen (SLA, with less cross-reactivity against Chagas disease patients' sera. SIGNIFICANCE: Our results are the first evidence of leishmania proteins that are specifically recognized by sera from individuals who are putatively resistant to VL. In addition, these data highlight the possibility of using specific proteins in serological tests for the identification of asymptomatic infected individuals.

  3. Malaria vaccine candidate antigen targeting the pre-erythrocytic stage of Plasmodium falciparum produced at high level in plants.

    Science.gov (United States)

    Voepel, Nadja; Boes, Alexander; Edgue, Güven; Beiss, Veronique; Kapelski, Stephanie; Reimann, Andreas; Schillberg, Stefan; Pradel, Gabriele; Fendel, Rolf; Scheuermayer, Matthias; Spiegel, Holger; Fischer, Rainer

    2014-11-01

    Plants have emerged as low-cost production platforms suitable for vaccines targeting poverty-related diseases. Besides functional efficacy, the stability, yield, and purification process determine the production costs of a vaccine and thereby the feasibility of plant-based production. We describe high-level plant production and functional characterization of a malaria vaccine candidate targeting the pre-erythrocytic stage of Plasmodium falciparum. CCT, a fusion protein composed of three sporozoite antigens (P. falciparum cell traversal protein for ookinetes and sporozoites [PfCelTOS], P. falciparum circumsporozoite protein [PfCSP], and P. falciparum thrombospondin-related adhesive protein [PfTRAP]), was transiently expressed by agroinfiltration in Nicotiana benthamiana leaves, accumulated to levels up to 2 mg/g fresh leaf weight (FLW), was thermostable up to 80°C and could be purified to >95% using a simple two-step procedure. Reactivity of sera from malaria semi-immune donors indicated the immunogenic conformation of the purified fusion protein consisting of PfCelTOS, PfCSP_TSR, PfTRAP_TSR domains (CCT) protein. Total IgG from the CCT-specific mouse immune sera specifically recognized P. falciparum sporozoites in immunofluorescence assays and induced up to 35% inhibition in hepatocyte invasion assays. Featuring domains from three promising sporozoite antigens with different roles (attachment and cell traversal) in the hepatocyte invasion process, CCT has the potential to elicit broader immune responses against the pre-erythrocytic stage of P. falciparum and represents an interesting new candidate, also as a component of multi-stage, multi-subunit malaria vaccine cocktails.

  4. Cloning,expression,and protective immunity in mice of a gene encoding the diagnostic antigen P-29 of Echinococcus granulosus

    Institute of Scientific and Technical Information of China (English)

    Zhiyun Shi; Yana Wang; Zongji Li; Zhaoyu Li; Yang Bo; Rui Ma; Wei Zhao

    2009-01-01

    Taeniid tapeworm Echinococcus granulosus is the causative agent of Echinococcosis,an important zoonosis with worldwide distribution.In this study,a diagnostic antigen P-29 was cloned from E.granulosus and expressed in Escherichia coli.Sequence analysis showed that EgP-29 contains 717-bp open reading frame and encodes a protein of 238 amino acid residues with a predicted molecular weight of 27.1 kDa.The recombinant EgP-29(rEgP-29)could be recognized with antimice sera in Western blotting.The specific antibody was detected by enzyme-linked immunosorbent assay.Mice vaccinated with rEgP-29 and challenged intraperitoneally with E.granulosus protoscoleces revealed significant protective immunity of 96.6%(P<0.05),compared with the control group.Thus,rEgP-29protein is a promising candidate for an effective vaccine to prevent secondary echinococcosis.

  5. African swine fever virus serotype-specific proteins are significant protective antigens for African swine fever

    Science.gov (United States)

    African swine fever (ASF) is an emerging disease threat for the swine industry worldwide. No ASF vaccine is available and progress is hindered by lack of knowledge concerning the extent of African swine fever virus (ASFV) strain diversity and the viral antigens conferring type specific protective im...

  6. Cholera toxin-B (ctxB) antigen expressing Salmonella Typhimurium polyvalent vaccine exerts protective immune response against Vibrio cholerae infection.

    Science.gov (United States)

    Vishwakarma, Vikalp; Sahoo, Sushree Sangita; Das, Susmita; Ray, Shilpa; Hardt, Wolf-Dietrich; Suar, Mrutyunjay

    2015-04-08

    Live attenuated vaccines are cost effective approach for preventing a broad range of infectious diseases, and thus are of great interest. However, immune-defects can predispose the patient to infections by the vaccine candidate itself. So far, few live vaccine candidates have been designed specifically for immune compromised individuals. Recently, we reported a new Salmonella Typhimurium Z234-vaccine strain (Periaswamy et al., PLoS ONE 2012;7:e45433), which was specifically attenuated in the NADPH-oxidase deficient host. In the present study, the Z234-vaccine strain was further engineered to express heterologous antigen (Vibrio cholerae toxin antigen subunit-B, i.e. CtxB) with the intention of creating a vector for simultaneous protection against Cholera and Salmonellosis. The primary aim of this study was to ensure the expression of CtxB antigen by the recombinant vaccine strain Z234-pMS101. The antigen CtxB was expressed through Z234 as a fusion protein with N-terminal signal sequence of Salmonella outer protein (SopE), an effector protein from Salmonella under the control of SopE promoter. The CtxB-expressing plasmid construct pMS101 (pM968-pSopE-ctxB) was found to be stable both in vitro and in vivo. In an oral mouse infection model, the vaccine strain Z234-pMS101 efficiently colonized the host gut. The extent of protection was confirmed after challenging the immunized hosts with live V. cholerae. Vaccinated mice showed reduced gut colonization by V. cholerae. Further assessment of immunological parameters supported the possibility of conferring effective immune response by Z234-pMS101 vaccine strain. Overall, the Z234-pMS101 vaccine strain showed potential as a promising polyvalent vaccine candidate to protect against S. Typhimurium and V. cholerae infection simultaneously.

  7. Tomatine Adjuvantation of Protective Immunity to a Major Pre-erythrocytic Vaccine Candidate of Malaria is Mediated via CD8+ T Cell Release of IFN-γ

    Directory of Open Access Journals (Sweden)

    Karen G. Heal

    2010-01-01

    Full Text Available The glycoalkaloid tomatine, derived from the wild tomato, can act as a powerful adjuvant to elicit an antigen-specific cell-mediated immune response to the circumsporozoite (CS protein, a major pre-erythrocytic stage malaria vaccine candidate antigen. Using a defined MHC-class-I-restricted CS epitope in a Plasmodium berghei rodent model, antigen-specific cytotoxic T lymphocyte activity and IFN-γ secretion ex vivo were both significantly enhanced compared to responses detected from similarly stimulated splenocytes from naive and tomatine-saline-immunized mice. Further, through lymphocyte depletion it is demonstrated that antigen-specific IFN-γ is produced exclusively by the CD8+ T cell subset. We conclude that the processing of the P. berghei CS peptide as an exogenous antigen and its presentation via MHC class I molecules to CD8+ T cells leads to an immune response that is an in vitro correlate of protection against pre-erythrocytic malaria. Further characterization of tomatine as an adjuvant in malaria vaccine development is indicated.

  8. Population genomic scan for candidate signatures of balancing selection to guide antigen characterization in malaria parasites.

    Directory of Open Access Journals (Sweden)

    Alfred Amambua-Ngwa

    Full Text Available Acquired immunity in vertebrates maintains polymorphisms in endemic pathogens, leading to identifiable signatures of balancing selection. To comprehensively survey for genes under such selection in the human malaria parasite Plasmodium falciparum, we generated paired-end short-read sequences of parasites in clinical isolates from an endemic Gambian population, which were mapped to the 3D7 strain reference genome to yield high-quality genome-wide coding sequence data for 65 isolates. A minority of genes did not map reliably, including the hypervariable var, rifin, and stevor families, but 5,056 genes (90.9% of all in the genome had >70% sequence coverage with minimum read depth of 5 for at least 50 isolates, of which 2,853 genes contained 3 or more single nucleotide polymorphisms (SNPs for analysis of polymorphic site frequency spectra. Against an overall background of negatively skewed frequencies, as expected from historical population expansion combined with purifying selection, the outlying minority of genes with signatures indicating exceptionally intermediate frequencies were identified. Comparing genes with different stage-specificity, such signatures were most common in those with peak expression at the merozoite stage that invades erythrocytes. Members of clag, PfMC-2TM, surfin, and msp3-like gene families were highly represented, the strongest signature being in the msp3-like gene PF10_0355. Analysis of msp3-like transcripts in 45 clinical and 11 laboratory adapted isolates grown to merozoite-containing schizont stages revealed surprisingly low expression of PF10_0355. In diverse clonal parasite lines the protein product was expressed in a minority of mature schizonts (<1% in most lines and ∼10% in clone HB3, and eight sub-clones of HB3 cultured separately had an intermediate spectrum of positive frequencies (0.9 to 7.5%, indicating phase variable expression of this polymorphic antigen. This and other identified targets of balancing

  9. Enhanced and durable protective immune responses induced by a cocktail of recombinant BCG strains expressing antigens of multistage of Mycobacterium tuberculosis.

    Science.gov (United States)

    Liang, Jinping; Teng, Xindong; Yuan, Xuefeng; Zhang, Ying; Shi, Chunwei; Yue, Tingting; Zhou, Lei; Li, Jianrong; Fan, Xionglin

    2015-08-01

    Although Bacillus Calmette-Guérin (BCG) vaccine confers protection from Mycobacterium tuberculosis infection in children, its immune protection gradually wanes over time, and consequently leads to an inability to prevent the reactivation of latent infection of M. tuberculosis. Therefore, improving BCG for better control of tuberculosis (TB) is urgently needed. We thus hypothesized that recombinant BCG overexpressing immunodominant antigens expressed at different growth stages of M. tuberculosis could provide a more comprehensive protection against primary and latent M. tuberculosis infection. Here, a novel cocktail of recombinant BCG (rBCG) strains, namely ABX, was produced by combining rBCG::85A, rBCG::85B, and rBCG::X, which overexpressed respective multistage antigens Ag85A, Ag85B, and HspX of M. tuberculosis. Our results showed that ABX was able to induce a stronger immune protection than individual rBCGs or BCG against primary TB infection in C57BL/6 mice. Mechanistically, the immune protection was attributed to stronger antigen-specific CD4(+) Th1 responses, higher numbers of IFN-γ(+) CD4(+) TEM and IL-2(+) CD8(+) TCM cells elicited by ABX. These findings thus provide a novel strategy for the improvement of BCG efficacy and potentially a promising prophylactic TB vaccine candidate, warranting further investigation.

  10. [Induction of protective antiamebic immunity in hamsters with heterologous antigens].

    Science.gov (United States)

    Jiménez Cardoso, J M; Jiménez, E; de Jesús Bernal, M; Kumate, J

    1989-01-01

    Two hundred and twenty-five Syrian golden hamsters were used. Twenty five of them served as the control group. All other hamsters were intradermal immunized, once a week for four weeks, with a mixture of amebic proteins, mixed with complete Freund adjuvant, obtained from 5 x 10(5) homogenized dead amebic trophozoites from five different strains. Each group of hamsters (five groups of 40 animals each) were immunized with one of the following strains: E. histolytica HM-531, HJ-1, HM1-IMSS, E. chattoni PM-4 and PM-5. All hamsters, including those from the control group, were later inoculated with 0.2 mL equivalent to 1 x 10(5) live trophozoites from the different strains grown in axenic TYI-S-33 medium. Inoculation was performed by direct injection into the liver. The hamsters were sacrificed eight days later and their livers examined. All non-immunized animals showed extensive gross hepatic nodular abscesses. The liver of immunized hamsters showed mild to moderate lesions: the histopathological striking feature was non-specific granulomata. It is concluded that the immunized animals inoculated with homologous stock showed protective immunity to amebic infections. In other cases, immunity was seen though they were inoculated with a heterologous stock.

  11. Neutralising immunogenicity of a polyepitope antigen expressed in a transgenic food plant: a novel antigen to protect against measles.

    Science.gov (United States)

    Bouche, Fabienne B; Marquet-Blouin, Estelle; Yanagi, Yusuke; Steinmetz, Andre; Muller, Claude P

    2003-05-16

    Transgenic carrot plants were developed expressing a designer polyepitope combining tandem repeats of a protective loop-forming B cell epitope (H386-400) of the measles virus hemagglutinin protein with a human promiscuous, measles-unrelated T cell epitope (tt830-844). Despite the sensitivity of the loop conformation to its molecular environment, proper folding was confirmed by conformation-dependent monoclonal antibodies. The antibodies also reacted with the boiled antigen in Western blot. Immunisation of mice peritoneally with carrot plant extracts induced high titers of antibodies that crossreacted strongly with the virus. Furthermore, the sera neutralised field isolates of different geographic origins and genotypes in a modified plaque reduction neutralisation assay performed on CD150-transfected Vero cells. These results demonstrate that transgenic carrot plants can serve as an efficient expression system to produce highly immunogenic, randomly assembled polyepitope antigens. The combined features of the selected epitopes and the potential of the plant expression system may pave the way towards new vaccines against measles.

  12. Vaccination with Trypomastigote Surface Antigen 1-Encoding Plasmid DNA Confers Protection against Lethal Trypanosoma cruzi Infection

    OpenAIRE

    1998-01-01

    DNA vaccination was evaluated with the experimental murine model of Trypanosoma cruzi infection as a means to induce antiparasite protective immunity, and the trypomastigote surface antigen 1 (TSA-1), a target of anti-T. cruzi antibody and major histocompatibility complex (MHC) class I-restricted CD8+ cytotoxic T-lymphocyte (CTL) responses, was used as the model antigen. Following the intramuscular immunization of H-2b and H-2d mice with a plasmid DNA encoding an N-terminally truncated TSA-1 ...

  13. 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.

  14. Protection of aouts monkeys after immunization with recombinant antigens of Plasmodium falciparum

    Directory of Open Access Journals (Sweden)

    Burhard Enders

    1992-01-01

    Full Text Available The genus Aotus spp. (owl monkey is one of the WHO recommended experimental models for Plasmodium falciparum blood stage infection, especially relevant for vaccination studies with asexual blood stage antigens of this parasite. For several immunization trials with purified recombinant merozoite/schizont antigens, the susceptible Aouts kenotypes II, III, IV and VI were immunized with Escherichia coli derived fusion proteins containg partial sequences of the proteins MSAI (merozoite surface antigen I, SERP (serine-strech protein and HRPII (histidine alanine rich protein II as well as with a group of recombinant antigens obtained by an antiserum raised against a protective 41 kD protein band. The subcutaneous application (3x of the antigen preparations was carried out in intact animals followed by splenectomy prior to challange, in order to increase the susceptibility of the experimental hosts to the parasite. A partial sequence of HRPII, the combination of three different fusion proteins of the 41 kD group and mixture of two sequences of SERP in the presence of the modified Al(OH3 adjuvant conferred significant protection against a challange infection with P. falciparum blood stages (2-5 x 10 (elevado a sexta potência i. RBC. Monkey immunized with the MS2-fusion protein carrying the N-terminal part of the 195 kD precursor of the major merozoite surface antigens induced only marginal protection showing some correlation between antibody titer and degree of parasitaemia. Based on the protective capacity of these recombinant antigens we have expressed two hybrid proteins (MS2/SERP/HRPII and SERP/MSAI/HRPII in E. coli containing selected partial sequences of SERP, HRPII and MSAI. Antibodies raised against both hybrid proteins in rabbits and Aotus monkeys recognize the corresponding schizont polypeptides. In two independent immunization trials using 13 animals (age 7 months to 3 years we could show that immunization of Aotus monkeys with either of the

  15. Subcutaneous immunization with a novel immunogenic candidate (urease) confers protection against Brucella abortus and Brucella melitensis infections.

    Science.gov (United States)

    Abkar, Morteza; Amani, Jafar; Sahebghadam Lotfi, Abbas; Nikbakht Brujeni, Gholamreza; Alamian, Saeed; Kamali, Mehdi

    2015-08-01

    Brucellosis is a world prevalent endemic illness that is transmitted from domestic animals to humans. Brucella spp. exploits urease for survival in the harsh conditions of stomach during the gastrointestinal infection. In this study, we examined the immune response and the protection elicited by using recombinant Brucella urease (rUrease) vaccination in BALB/c mice. The urease gene was cloned in pET28a and the resulting recombinant protein was employed as subunit vaccine. Recombinant protein was administered subcutaneously and intraperitoneally. Dosage reduction was observed with subcutaneous (SC) vaccination when compared with intraperitoneal (IP) vaccination. rUrease induced mixed Th1-Th2 immune responses with high titers of specific IgG1 and IgG2a. In lymphocyte proliferation assay, splenocytes from IP and SC-vaccinated mice displayed a strong recall proliferative response with high amounts of IL-4, IL-12 and IFN-γ production. Vaccinated mice were challenged with virulent Brucella melitensis, B. abortus and B. suis. The SC vaccination route exhibited a higher degree of protection than IP vaccination (p value ≤ 0.05). Altogether, our results indicated that rUrease could be a useful antigen candidate for the development of subunit vaccines against brucellosis.

  16. Redefining an epitope of a malaria vaccine candidate, with antibodies against the N-terminal MSA-2 antigen of Plasmodium harboring non-natural peptide bonds.

    Science.gov (United States)

    Lozano, José Manuel; Guerrero, Yuly Andrea; Alba, Martha Patricia; Lesmes, Liliana Patricia; Escobar, José Oswaldo; Patarroyo, Manuel Elkin

    2013-10-01

    The aim of obtaining novel vaccine candidates against malaria and other transmissible diseases can be partly based on selecting non-polymorphic peptides from relevant antigens of pathogens, which have to be then precisely modified for inducing a protective immunity against the disease. Bearing in mind the high degree of the MSA-2(21-40) peptide primary structure's genetic conservation among malaria species, and its crucial role in the high RBC binding ability of Plasmodium falciparum (the main agent causing malaria), structurally defined probes based on non-natural peptide-bond isosteres were thus designed. Thus, two peptide mimetics were obtained (so-called reduced amide pseudopeptides), in which naturally made amide bonds of the (30)FIN(32)-binding motif of MSA-2 were replaced with ψ-[CH2-NH] methylene amide isostere bonds, one between the F-I and the second between I-N amino acid pairs, respectively, coded as ψ-128 ψ-130. These peptide mimetics were used to produce poly- and monoclonal antibodies in Aotus monkeys and BALB/c mice. Parent reactive mice-derived IgM isotype cell clones were induced to Ig isotype switching to IgG sub-classes by controlled in vitro immunization experiments. These mature isotype immunoglobulins revealed a novel epitope in the MSA-2(25-32) antigen and two polypeptides of rodent malaria species. Also, these antibodies' functional activity against malaria was tested by in vitro assays, demonstrating high efficacy in controlling infection and evidencing neutralizing capacity for the rodent in vivo malaria infection. The neutralizing effect of antibodies induced by site-directed designed peptide mimetics on Plasmodium's biological development make these pseudopeptides a valuable tool for future development of immunoprophylactic strategies for controlling malarial infection.

  17. A Mr 90 000 surface polypeptide of Trypanosoma cruzi as a candidate for a Chagas' disease diagnostic antigen.

    Science.gov (United States)

    Dragon, E A; Brothers, V M; Wrightsman, R A; Manning, J

    1985-09-01

    Trypanosoma cruzi (Peru strain) trypomastigotes and epimastigotes were biosynthetically labeled with [35S]methionine, and the proteins were analyzed by two dimensional polyacrylamide gel electrophoresis (2D-PAGE). 2D-PAGE analysis of the trypomastigotes showed a complex array of polypeptides with distinct clusters at Mr 88 000-92 000, isoelectric point (pI) 5.6-6.0, and Mr 72 000-76 000, pI 5.6-5.8. 2D-PAGE analysis of the epimastigotes did not show the cluster of polypeptides at Mr 90 000. When the trypomastigote lysate was reacted with sera from either mice or humans chronically infected with T. cruzi, 10-50 polypeptides were immunoprecipitated. Five of these polypeptides were recognized by all sera tested. However, of these polypeptides, only three, two of Mr 90 000 and one of Mr 150 000, can be identified by immunoreaction of [35S]methionine-labeled live parasites as surface proteins of T. cruzi trypomastigotes. 125I-iminobiotinylated surface proteins isolated from T. cruzi trypomastigotes were immunoprecipitated with the same series of sera as described above. Chagasic sera immunoprecipitated an antigen of Mr 90 000. The [35S]methionine and 125I-labeled Mr 90 000 polypeptides were not immunoprecipitated with sera from individuals infected with Leishmania donovani, Leishmania braziliensis, Leishmania tropica or Leishmania mexicana. These data indicate that a surface polypeptide of Mr 90000, pI 5.8-5.9 is a viable candidate for a Chagas' disease diagnostic antigen.

  18. Protective efficacy and immune responses by homologous prime-booster immunizations of a novel inactivated Salmonella Gallinarum vaccine candidate

    Science.gov (United States)

    2016-01-01

    Purpose Salmonella enterica serovar Gallinarum (SG) ghost vaccine candidate was recently constructed. In this study, we evaluated various prime-boost vaccination strategies using the candidate strain to optimize immunity and protection efficacy against fowl typhoid. Materials and Methods The chickens were divided into five groups designated as group A (non-immunized control), group B (orally primed and boosted), group C (primed orally and boosted intramuscularly), group D (primed and boosted intramuscularly), and group E (primed intramuscularly and boosted orally). The chickens were primed with the SG ghost at 7 days of age and were subsequently boosted at the fifth week of age. Post-immunization, the plasma IgG and intestinal secretory IgA (sIgA) levels, and the SG antigen-specific lymphocyte stimulation were monitored at weekly interval and the birds were subsequently challenged with a virulent SG strain at the third week post-second immunization. Results Chickens in group D showed an optimized protection with significantly increased plasma IgG, sIgA, and lymphocyte stimulation response compared to all groups. The presence of CD4+ and CD8+ T cells and monocyte/macrophage (M/M) in the spleen, and splenic expression of cytokines such as interferon γ (IFN-γ) and interleukin 6 (IL-6) in the immunized chickens were investigated. The prime immunization induced significantly higher splenic M/M population and mRNA levels of IFN-γ whereas the booster showed increases of splenic CD4+ and CD8+ T-cell population and IL-6 cytokine in mRNA levels. Conclusion Our results indicate that the prime immunization with the SG ghost vaccine induced Th1 type immune response and the booster elicited both Th1- and Th2-related immune responses. PMID:27489805

  19. Detection of bovine leukocyte antigen DRB3 alleles as candidate markers for clinical mastitis resistance in Holstein x Zebu.

    Science.gov (United States)

    Duangjinda, M; Buayai, D; Pattarajinda, V; Phasuk, Y; Katawatin, S; Vongpralub, T; Chaiyotvittayakul, A

    2009-02-01

    Bovine leukocyte antigen DRB3 alleles from Holstein x Zebu crossbred dairy cows (n = 409) were analyzed using the PCR-RFLP technique. Exon II of DRB3 was amplified using locus-specific primers (HLO30/HLO32), followed by digestion with 3 restriction enzymes (RsaI, BstyI, and HaeIII). Forty alleles were found with frequency ranging from 0.005 to 0.139. The most frequently detected alleles of Holstein x Zebu were DRB3*16, *51, *23, *11, *8, and *1, accounting for 61.12% of the alleles in the population. Detection of candidate alleles for clinical mastitis occurrence was performed by logistic regression. It was found that percentage of Holstein fraction in crossbred cows had a nonsignificant effect (P > 0.05). However, parity had a significant effect on mastitis occurrence. In addition, DRB3*1 and *52 were the most associated with the occurrence of clinical mastitis, whereas *15, *51, and *22 were associated with resistance in crossbred populations. This is the first report of association of DRB3*15 and *51 with mastitis resistance. The association was validated by examining the candidate alleles in another commercial population. Highly susceptible (n = 43) and resistant (n = 42) groups of Holstein x Zebu cows were investigated. The result confirmed that DRB3*1 and *52 could be considered as susceptibility alleles, whereas *15, *51, and *22 could be considered as resistant alleles in Holstein x Zebu raised under tropical conditions. In addition, allele effects on 305-d milk production were estimated by BLUP. It was shown that most alleles associated with high clinical mastitis occurrence were related to increased milk yield. This study revealed that allele DRB3*10 had the greatest effect on increasing milk yield with moderate resistance to clinical mastitis, which could be used as a potential marker for selection in dairy genetic evaluation.

  20. Toxoplasma gondii Elongation Factor 1-Alpha (TgEF-1α) Is a Novel Vaccine Candidate Antigen against Toxoplasmosis

    Science.gov (United States)

    Wang, Shuai; Zhang, Zhenchao; Wang, Yujian; Gadahi, Javaid A.; Xu, Lixin; Yan, Ruofeng; Song, Xiaokai; Li, Xiangrui

    2017-01-01

    Toxoplasma gondii (T. gondii) is an obligate intracellular parasite which can infect almost all warm-blood animals, leading to toxoplasmosis. Screening and discovery of an effective vaccine candidate or new drug target is crucial for the control of this disease. In this study, the recombinant T. gondii elongation factor 1-alpha (rTgEF-1α) was successfully expressed in in Escherichia coli. Passive immunization of mice with anti-rTgEF-1α polyclonal antibody following challenge with a lethal dose of tachyzoites significantly increased the survival time compared with PBS control group. The survival time of mice challenged with tachyzoites pretreated with anti-rTgEF-1α PcAb also was significantly increased. Invasion of tachyzoites into mouse macrophages was significantly inhibited in the anti-rTgEF-1α PcAb pretreated group. Mice vaccinated with rTgEF-1α induced a high level of specific anti-T. gondii antibodies and production of IFN-gamma, interleukin-4. The expression levels of MHC-I and MHC-II molecules as well as the percentages of CD4+ and CD8+ T cells in mice vaccinated with rTgEF-1α was significantly increased, respectively (P < 0.05), compared with all the controls. Immunization with rTgEF-1α significantly (P < 0.05) prolonged survival time (14.53 ± 1.72 days) after challenge infection with the virulent T. gondii RH strain. These results indicate that T. gondii EF-1α plays an essential role in mediating host cell invasion by the parasite and, as such, could be a candidate vaccine antigen against toxoplasmosis.

  1. Disaccharides Protect Antigens from Drying-Induced Damage in Routinely Processed Tissue Sections.

    Science.gov (United States)

    Boi, Giovanna; Scalia, Carla Rossana; Gendusa, Rossella; Ronchi, Susanna; Cattoretti, Giorgio

    2016-01-01

    Drying of the tissue section, partial or total, during immunostaining negatively affects both the staining of tissue antigens and the ability to remove previously deposited antibody layers, particularly during sequential rounds of de-staining and re-staining for multiple antigens. The cause is a progressive loss of the protein-associated water up to the removal of the non-freezable water, a step which abolishes the immunoavailability of the epitope. In order to describe and prevent these adverse effects, we tested, among other substances, sugars, which are known to protect unicellular organisms from freezing and dehydration, and stabilize drugs and reagents in solid state form in medical devices. Disaccharides (lactose, sucrose) prevented the air drying-induced antigen masking and protected tissue-bound antigens and antibodies from air drying-induced damage. Complete removal of the bound antibody layers by chemical stripping was permitted if lactose was present during air drying. Lactose, sucrose and other disaccharides prevent air drying artifacts, allow homogeneous, consistent staining and the reuse of formalin-fixed, paraffin-embedded tissue sections for repeated immunostaining rounds by guaranteeing constant staining quality in suboptimal hydration conditions.

  2. Recombinant 35-kDa inclusion membrane protein IncA as a candidate antigen for serodiagnosis of Chlamydophila pecorum.

    Science.gov (United States)

    Mohamad, Khalil Yousef; Rekiki, Abdessalem; Berri, Mustapha; Rodolakis, Annie

    2010-07-14

    Chlamydophila pecorum strains are commonly found in the intestine and vaginal mucus of asymptomatic ruminants and may therefore induce a positive serological response when the animals are tested for C. abortus. They have also been associated with different pathological diseases in ruminants, swine and koala. The aim of this study was to identify specific C. pecorum immunodominant antigens which could be used in ELISA tests allowing to distinguish between animals infected with C. pecorum and those infected with other chlamydial species. A gene encoding 35-kDa inclusion membrane protein incA of C. pecorum was isolated by immunoscreening of the C. pecorum DNA library using ovine anti-C. pecorum antibodies. The recombinant IncA protein did not react with a murine serum directed against C. abortus but did react with a specific monoclonal antibody of C. pecorum and toward several ovine serum samples obtained after experimental infection with different C. pecorum strains. This protein could be a good candidate for specific diagnosis of C. pecorum infection.

  3. The role of Plasmodium falciparum variant surface antigens in protective immunity and vaccine development

    DEFF Research Database (Denmark)

    Hviid, Lars

    2010-01-01

    that development of PfEMP1-based vaccines to protect specifically against severe malaria syndromes-in particular PAM-is feasible. This review summarizes the evidence that VSAs are important targets of NAI, discusses why VSA-based vaccines might be feasible despite the extensive intra- and interclonal variation...... of VSAs, and how vaccines based on this type of antigens fit into the current global strategy to reduce, eliminate and eventually eradicate the burden of malaria....

  4. Blocking anthrax lethal toxin at the protective antigen channel by using structure-inspired drug design

    OpenAIRE

    Karginov, Vladimir A.; Nestorovich, Ekaterina M.; Moayeri, Mahtab; Leppla, Stephen H.; Bezrukov, Sergey M.

    2005-01-01

    Bacillus anthracis secretes three polypeptides: protective antigen (PA), lethal factor (LF), and edema factor (EF), which interact at the surface of mammalian cells to form toxic complexes. LF and EF are enzymes that target substrates within the cytosol; PA provides a heptameric pore to facilitate LF and EF transport into the cytosol. Other than administration of antibiotics shortly after exposure, there is currently no approved effective treatment for inhalational anthrax. Here we demonstrat...

  5. Identification of protective and broadly conserved vaccine antigens from the genome of extraintestinal pathogenic Escherichia coli.

    Science.gov (United States)

    Moriel, Danilo Gomes; Bertoldi, Isabella; Spagnuolo, Angela; Marchi, Sara; Rosini, Roberto; Nesta, Barbara; Pastorello, Ilaria; Corea, Vanja A Mariani; Torricelli, Giulia; Cartocci, Elena; Savino, Silvana; Scarselli, Maria; Dobrindt, Ulrich; Hacker, Jörg; Tettelin, Hervé; Tallon, Luke J; Sullivan, Steven; Wieler, Lothar H; Ewers, Christa; Pickard, Derek; Dougan, Gordon; Fontana, Maria Rita; Rappuoli, Rino; Pizza, Mariagrazia; Serino, Laura

    2010-05-18

    Extraintestinal pathogenic Escherichia coli (ExPEC) are a common cause of disease in both mammals and birds. A vaccine to prevent such infections would be desirable given the increasing antibiotic resistance of these bacteria. We have determined the genome sequence of ExPEC IHE3034 (ST95) isolated from a case of neonatal meningitis and compared this to available genome sequences of other ExPEC strains and a few nonpathogenic E. coli. We found 19 genomic islands present in the genome of IHE3034, which are absent in the nonpathogenic E. coli isolates. By using subtractive reverse vaccinology we identified 230 antigens present in ExPEC but absent (or present with low similarity) in nonpathogenic strains. Nine antigens were protective in a mouse challenge model. Some of them were also present in other pathogenic non-ExPEC strains, suggesting that a broadly protective E. coli vaccine may be possible. The gene encoding the most protective antigen was detected in most of the E. coli isolates, highly conserved in sequence and found to be exported by a type II secretion system which seems to be nonfunctional in nonpathogenic strains.

  6. Advax-adjuvanted recombinant protective antigen provides protection against inhalational anthrax that is further enhanced by addition of murabutide adjuvant.

    Science.gov (United States)

    Feinen, Brandon; Petrovsky, Nikolai; Verma, Anita; Merkel, Tod J

    2014-04-01

    Subunit vaccines against anthrax based on recombinant protective antigen (PA) potentially offer more consistent and less reactogenic anthrax vaccines but require adjuvants to achieve optimal immunogenicity. This study sought to determine in a murine model of pulmonary anthrax infection whether the polysaccharide adjuvant Advax or the innate immune adjuvant murabutide alone or together could enhance PA immunogenicity by comparison to an alum adjuvant. A single immunization with PA plus Advax adjuvant afforded significantly greater protection against aerosolized Bacillus anthracis Sterne strain 7702 than three immunizations with PA alone. Murabutide had a weaker adjuvant effect than Advax when used alone, but when murabutide was formulated together with Advax, an additive effect on immunogenicity and protection was observed, with complete protection after just two doses. The combined adjuvant formulation stimulated a robust, long-lasting B-cell memory response that protected mice against an aerosol challenge 18 months postimmunization with acceleration of the kinetics of the anamnestic IgG response to B. anthracis as reflected by ∼4-fold-higher anti-PA IgG titers by day 2 postchallenge versus mice that received PA with Alhydrogel. In addition, the combination of Advax plus murabutide induced approximately 3-fold-less inflammation than Alhydrogel as measured by in vivo imaging of cathepsin cleavage resulting from injection of ProSense 750. Thus, the combination of Advax and murabutide provided enhanced protection against inhalational anthrax with reduced localized inflammation, making this a promising next-generation anthrax vaccine adjuvanting strategy.

  7. Intragastric immunization with recombinant Lactobacillus casei expressing flagellar antigen confers antibody-independent protective immunity against Salmonella enterica serovar Enteritidis

    NARCIS (Netherlands)

    Kajikawa, A.; Satoh, E.; Leer, R.J.; Yamamoto, S.; Igimi, S.

    2007-01-01

    A recombinant Lactobacillus casei expressing a flagellar antigen from Salmonella enterica serovar Enteritidis was constructed and evaluated as a mucosal vaccine. Intragastric immunization of the recombinant strain conferred protective immunity against Salmonella infection in mice. This immunization

  8. Pathogens Inactivated by Low-Energy-Electron Irradiation Maintain Antigenic Properties and Induce Protective Immune Responses

    Science.gov (United States)

    Fertey, Jasmin; Bayer, Lea; Grunwald, Thomas; Pohl, Alexandra; Beckmann, Jana; Gotzmann, Gaby; Casado, Javier Portillo; Schönfelder, Jessy; Rögner, Frank-Holm; Wetzel, Christiane; Thoma, Martin; Bailer, Susanne M.; Hiller, Ekkehard; Rupp, Steffen; Ulbert, Sebastian

    2016-01-01

    Inactivated vaccines are commonly produced by incubating pathogens with chemicals such as formaldehyde or β-propiolactone. This is a time-consuming process, the inactivation efficiency displays high variability and extensive downstream procedures are often required. Moreover, application of chemicals alters the antigenic components of the viruses or bacteria, resulting in reduced antibody specificity and therefore stimulation of a less effective immune response. An alternative method for inactivation of pathogens is ionizing radiation. It acts very fast and predominantly damages nucleic acids, conserving most of the antigenic structures. However, currently used irradiation technologies (mostly gamma-rays and high energy electrons) require large and complex shielding constructions to protect the environment from radioactivity or X-rays generated during the process. This excludes them from direct integration into biological production facilities. Here, low-energy electron irradiation (LEEI) is presented as an alternative inactivation method for pathogens in liquid solutions. LEEI can be used in normal laboratories, including good manufacturing practice (GMP)- or high biosafety level (BSL)-environments, as only minor shielding is necessary. We show that LEEI efficiently inactivates different viruses (influenza A (H3N8), porcine reproductive and respiratory syndrome virus (PRRSV), equine herpesvirus 1 (EHV-1)) and bacteria (Escherichia coli) and maintains their antigenicity. Moreover, LEEI-inactivated influenza A viruses elicit protective immune responses in animals, as analyzed by virus neutralization assays and viral load determination upon challenge. These results have implications for novel ways of developing and manufacturing inactivated vaccines with improved efficacy. PMID:27886076

  9. Vaccination with trypomastigote surface antigen 1-encoding plasmid DNA confers protection against lethal Trypanosoma cruzi infection.

    Science.gov (United States)

    Wizel, B; Garg, N; Tarleton, R L

    1998-11-01

    DNA vaccination was evaluated with the experimental murine model of Trypanosoma cruzi infection as a means to induce antiparasite protective immunity, and the trypomastigote surface antigen 1 (TSA-1), a target of anti-T. cruzi antibody and major histocompatibility complex (MHC) class I-restricted CD8(+) cytotoxic T-lymphocyte (CTL) responses, was used as the model antigen. Following the intramuscular immunization of H-2(b) and H-2(d) mice with a plasmid DNA encoding an N-terminally truncated TSA-1 lacking or containing the C-terminal nonapeptide tandem repeats, the antibody level, CTL response, and protection against challenge with T. cruzi were assessed. In H-2(b) mice, antiparasite antibodies were induced only by immunization with the DNA construct encoding TSA-1 containing the C-terminal repeats. However, both DNA constructs were efficient in eliciting long-lasting CTL responses against the protective H-2Kb-restricted TSA-1515-522 epitope. In H-2(d) mice, inoculation with either of the two TSA-1-expressing vectors effectively generated antiparasite antibodies and primed CTLs that lysed T. cruzi-infected cells in an antigen-specific, MHC class I-restricted, and CD8(+)-T-cell-dependent manner. When TSA-1 DNA-vaccinated animals were challenged with T. cruzi, 14 of 22 (64%) H-2(b) and 16 of 18 (89%) H-2(d) mice survived the infection. The ability to induce significant murine anti-T. cruzi protective immunity by immunization with plasmid DNA expressing TSA-1 provides the basis for the application of this technology in the design of optimal DNA multicomponent anti-T. cruzi vaccines which may ultimately be used for the prevention or treatment of Chagas' disease.

  10. Expression of VP7, a Bluetongue virus group specific antigen by viral vectors: analysis of the induced immune responses and evaluation of protective potential in sheep.

    Directory of Open Access Journals (Sweden)

    Coraline Bouet-Cararo

    Full Text Available Bluetongue virus (BTV is an economically important Orbivirus transmitted by biting midges to domestic and wild ruminants. The need for new vaccines has been highlighted by the occurrence of repeated outbreaks caused by different BTV serotypes since 1998. The major group-reactive antigen of BTV, VP7, is conserved in the 26 serotypes described so far, and its role in the induction of protective immunity has been proposed. Viral-based vectors as antigen delivery systems display considerable promise as veterinary vaccine candidates. In this paper we have evaluated the capacity of the BTV-2 serotype VP7 core protein expressed by either a non-replicative canine adenovirus type 2 (Cav-VP7 R0 or a leporipoxvirus (SG33-VP7, to induce immune responses in sheep. Humoral responses were elicited against VP7 in almost all animals that received the recombinant vectors. Both Cav-VP7 R0 and SG33-VP7 stimulated an antigen-specific CD4+ response and Cav-VP7 R0 stimulated substantial proliferation of antigen-specific CD8+ lymphocytes. Encouraged by the results obtained with the Cav-VP7 R0 vaccine vector, immunized animals were challenged with either the homologous BTV-2 or the heterologous BTV-8 serotype and viral burden in plasma was followed by real-time RT-PCR. The immune responses triggered by Cav-VP7 R0 were insufficient to afford protective immunity against BTV infection, despite partial protection obtained against homologous challenge. This work underscores the need to further characterize the role of BTV proteins in cross-protective immunity.

  11. Expression of VP7, a Bluetongue Virus Group Specific Antigen by Viral Vectors: Analysis of the Induced Immune Responses and Evaluation of Protective Potential in Sheep

    Science.gov (United States)

    Bouet-Cararo, Coraline; Contreras, Vanessa; Caruso, Agathe; Top, Sokunthea; Szelechowski, Marion; Bergeron, Corinne; Viarouge, Cyril; Desprat, Alexandra; Relmy, Anthony; Guibert, Jean-Michel; Dubois, Eric; Thiery, Richard; Bréard, Emmanuel; Bertagnoli, Stephane; Richardson, Jennifer; Foucras, Gilles; Meyer, Gilles; Schwartz-Cornil, Isabelle; Zientara, Stephan; Klonjkowski, Bernard

    2014-01-01

    Bluetongue virus (BTV) is an economically important Orbivirus transmitted by biting midges to domestic and wild ruminants. The need for new vaccines has been highlighted by the occurrence of repeated outbreaks caused by different BTV serotypes since 1998. The major group-reactive antigen of BTV, VP7, is conserved in the 26 serotypes described so far, and its role in the induction of protective immunity has been proposed. Viral-based vectors as antigen delivery systems display considerable promise as veterinary vaccine candidates. In this paper we have evaluated the capacity of the BTV-2 serotype VP7 core protein expressed by either a non-replicative canine adenovirus type 2 (Cav-VP7 R0) or a leporipoxvirus (SG33-VP7), to induce immune responses in sheep. Humoral responses were elicited against VP7 in almost all animals that received the recombinant vectors. Both Cav-VP7 R0 and SG33-VP7 stimulated an antigen-specific CD4+ response and Cav-VP7 R0 stimulated substantial proliferation of antigen-specific CD8+ lymphocytes. Encouraged by the results obtained with the Cav-VP7 R0 vaccine vector, immunized animals were challenged with either the homologous BTV-2 or the heterologous BTV-8 serotype and viral burden in plasma was followed by real-time RT-PCR. The immune responses triggered by Cav-VP7 R0 were insufficient to afford protective immunity against BTV infection, despite partial protection obtained against homologous challenge. This work underscores the need to further characterize the role of BTV proteins in cross-protective immunity. PMID:25364822

  12. 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

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

    OpenAIRE

    Ratna eGurung; Auriol ePurdie; Richard eWhittington; Douglas eBegg

    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 MA...

  14. Diversity of Francisella tularensis Schu4 antigens recognized by T lymphocytes after natural infections in humans: identification of candidate epitopes for inclusion in a rationally designed tularemia vaccine

    DEFF Research Database (Denmark)

    McMurry, Julie A; Gregory, Stephen H; Moise, Leonard;

    2007-01-01

    The T lymphocyte antigens, which may have a role in protection against tularemia, were predicted by immunoinformatics analysis of Francisella tularensis Schu4. Twenty-seven class II putative promiscuous epitopes and 125 putative class I supertype epitopes were chosen for synthesis; peptides were...

  15. Expression, purification, immunogenicity, and protective efficacy of a recombinant Tc24 antigen as a vaccine against Trypanosoma cruzi infection in mice.

    Science.gov (United States)

    Martinez-Campos, Viridiana; Martinez-Vega, Pedro; Ramirez-Sierra, Maria Jesus; Rosado-Vallado, Miguel; Seid, Christopher A; Hudspeth, Elissa M; Wei, Junfei; Liu, Zhuyun; Kwityn, Cliff; Hammond, Molly; Ortega-López, Jaime; Zhan, Bin; Hotez, Peter J; Bottazzi, Maria Elena; Dumonteil, Eric

    2015-08-26

    The Tc24 calcium binding protein from the flagellar pocket of Trypanosoma cruzi is under evaluation as a candidate vaccine antigen against Chagas disease. Previously, a DNA vaccine encoding Tc24 was shown to be an effective vaccine (both as a preventive and therapeutic intervention) in mice and dogs, as evidenced by reductions in T. cruzi parasitemia and cardiac amastigotes, as well as reduced cardiac inflammation and increased host survival. Here we developed a suitable platform for the large scale production of recombinant Tc24 (rTc24) and show that when rTc24 is combined with a monophosphoryl-lipid A (MPLA) adjuvant, the formulated vaccine induces a Th1-biased immune response in mice, comprised of elevated IgG2a antibody levels and interferon-gamma levels from splenocytes, compared to controls. These immune responses also resulted in statistically significant decreased T. cruzi parasitemia and cardiac amastigotes, as well as increased survival following T. cruzi challenge infections, compared to controls. Partial protective efficacy was shown regardless of whether the antigen was expressed in Escherichia coli or in yeast (Pichia pastoris). While mouse vaccinations will require further modifications in order to optimize protective efficacy, such studies provide a basis for further evaluations of vaccines comprised of rTc24, together with alternative adjuvants and additional recombinant antigens.

  16. Induction of protective T-helper 1 immune responses against Echinococcus granulosus in mice by a multi-T-cell epitope antigen based on five proteins

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    Majid Esmaelizad

    2013-06-01

    Full Text Available In this study, we designed an experiment to predict a potential immunodominant T-cell epitope and evaluate the protectivity of this antigen in immunised mice. The T-cell epitopes of the candidate proteins (EgGST, EgA31, Eg95, EgTrp and P14-3-3 were detected using available web-based databases. The synthesised DNA was subcloned into the pET41a+ vector and expressed in Escherichia coli as a fusion to glutathione-S-transferase protein (GST. The resulting chimeric protein was then purified by affinity chromatography. Twenty female C57BL/6 mice were immunised with the antigen emulsified in Freund's adjuvant. Mouse splenocytes were then cultured in Dulbecco's Modified Eagle's Medium in the presence of the antigen. The production of interferon-γ was significantly higher in the immunised mice than in the control mice (> 1,300 pg/mL, but interleukin (IL-10 and IL-4 production was not statistically different between the two groups. In a challenge study in which mice were infected with 500 live protoscolices, a high protectivity level (99.6% was demonstrated in immunised BALB/C mice compared to the findings in the control groups [GST and adjuvant (Adj ]. These results demonstrate the successful application of the predicted T-cell epitope in designing a vaccine against Echinococcus granulosus in a mouse model.

  17. A live attenuated BCG vaccine overexpressing multistage antigens Ag85B and HspX provides superior protection against Mycobacterium tuberculosis infection.

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    Yuan, Xuefeng; Teng, Xindong; Jing, Yukai; Ma, Jilei; Tian, Maopeng; Yu, Qi; Zhou, Lei; Wang, Ruibo; Wang, Weihua; Li, Li; Fan, Xionglin

    2015-12-01

    Tuberculosis (TB) remains one of the most menacing infectious diseases, although attenuated Mycobacterium bovis Bacillus Calmette-Guerin (BCG) vaccine has been widely used to protect children against primary TB. There are increasing evidences that rapid growing and dormant Mycobacterium tuberculosis (M. tuberculosis) coexist in vivo after infection. However, BCG vaccine only elicits cell-mediated immune responses to secretory antigens expressed by rapid growing pathogen. BCG vaccine is thus unable to thwart the reactivation of latent tuberculosis infection (LTBI), and its protection wanes over age after neonatal immunization. In order to extend its ability for a durable protection, a novel recombinant BCG (rBCG) strain, named rBCG::XB, was constructed by overexpressing immunodominant multistage antigens of Ag85B and HspX, which are expressed by both rapid replicating and dormant M. tuberculosis. Long-term protective effect and immunogenicity of rBCG::XB were compared with the parental BCG in vaccinated C57BL/6 mice. Our results demonstrated that rBCG::XB provided the stronger and long-lasting protection against M. tuberculosis H37Rv intranasal infection than BCG. The rBCG::XB not only elicited the more durable multistage antigen-specific CD4(+)Th1-biased immune responses and specific polyfunctional CD4(+)T cells but also augmented the CD8(+) CTL effects against Ag85B in vivo. In particular, higher levels of CD4(+) TEM and CD8(+) TCM cells, dominated by IL2(+) CD4(+) and CD8(+) TCM cells, were obtained in the spleen of rBCG::XB vaccinated mice. Therefore, our findings indicate that rBCG::XB is a promising candidate to improve the efficacy of BCG.

  18. Recombinant feline coronaviruses as vaccine candidates confer protection in SPF but not in conventional cats.

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    Bálint, Ádám; Farsang, Attila; Szeredi, Levente; Zádori, Zoltán; Belák, Sándor

    2014-03-14

    Feline infectious peritonitis virus (FIPV) is a major pathogen of Felidae. Despite the extensive efforts taken in the past decades, development of the "ideal" live attenuated FIPV vaccine was not successful yet. In the present study, we provide data of immunisation experiments with a recombinant FCoV pair differing only in the truncation (PBFIPV-DF-2) or completion (PBFIPV-DF-2-R3i) of their ORF3abc regions. In our previous in vivo studies, these viruses proved to show the characters of low virulent or avirulent FCoV phenotypes, respectively. Therefore, we hypothesised the ability of these viruses, as possible vaccine candidates, in conferring protection in specific pathogen free (SPF) Domestic Shorthair as well as in conventional purebred British Shorthair cats. In SPF cats, after two oronasal and two intramuscular vaccinations with two weeks intervals, both vaccine candidates provided 100% protection against lethal homologous challenge with the highly virulent FIPV DF-2 strain. In contrast, the conventional purebred British Shorthair cats did not develop protection when they were immunised with the same vaccination regimes. In these groups 100% of the PBFIPV-DF-2-R3i immunised animals developed antibody-dependent enhancement (ADE). Prolonged survival was observed in 40% of the animals, while 60% showed fulminant disease course. Genetic and more probably immunological differences between the SPF and non-SPF purebred kittens can explain the different outcome of the vaccination experiment. Our data highlight the diverse immune responses between SPF and conventional cats and suggest a decisive role of previous infection by heterologous causative agents in the outcome of the vaccination against FIP.

  19. Intranasal vaccination with leishmanial antigens protects golden hamsters (Mesocricetus auratus against Leishmania (Viannia Braziliensis infection.

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    Luzinei da Silva-Couto

    2015-01-01

    Full Text Available Previous results have shown that oral and intranasal administration of particulate Leishmania (Leishmania amazonensis antigens (LaAg partially protects mice against L. amazonensis infection. However, vaccination studies on species of the subgenus Viannia, the main causative agent of cutaneous and mucosal leishmaniasis in the Americas, have been hampered by the lack of easy-to-handle bio-models that accurately mimic the human disease. Recently, we demonstrated that the golden hamster is an appropriate model for studying the immunopathogenesis of cutaneous leishmaniasis caused by L. (Viannia braziliensis. Using the golden hamster model, our current study investigated whether the protective effect of intranasal immunisation with LaAg can be extended to L. braziliensis infection.Golden hamsters vaccinated with either two intranasal (IN doses of LaAg (10 µg or two intramuscular doses of LaAg (20 µg were challenged 2 weeks post-vaccination with L. braziliensis. The results showed that IN immunisation with LaAg significantly reduced lesion growth and parasitic load as well as serum IgG and IgG2 levels. At the experimental endpoint on day 114 post-infection, IN-immunised hamsters that were considered protected expressed IFN-γ and IL10 mRNA levels that returned to uninfected skin levels. In contrast to the nasal route, intramuscular (IM immunisation failed to provide protection.These results demonstrate for the first time that the nasal route of immunisation can induce cross protection against L. braziliensis infection.

  20. A dual TLR agonist adjuvant enhances the immunogenicity and protective efficacy of the tuberculosis vaccine antigen ID93.

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    Mark T Orr

    Full Text Available With over eight million cases of tuberculosis each year there is a pressing need for the development of new vaccines against Mycobacterium tuberculosis. Subunit vaccines consisting of recombinant proteins are an attractive vaccine approach due to their inherent safety compared to attenuated live vaccines and the uniformity of manufacture. Addition of properly formulated TLR agonist-containing adjuvants to recombinant protein vaccines enhances the antigen-specific CD4(+ T cell response characterized by IFN-γ and TNF, both of which are critical for the control of TB. We have developed a clinical stage vaccine candidate consisting of a recombinant fusion protein ID93 adjuvanted with the TLR4 agonist GLA-SE. Here we examine whether ID93+GLA-SE can be improved by the addition of a second TLR agonist. Addition of CpG containing DNA to ID93+GLA-SE enhanced the magnitude of the multi-functional TH1 response against ID93 characterized by co-production of IFN-γ, TNF, and IL-2. Addition of CpG also improved the protective efficacy of ID93+GLA-SE. Finally we demonstrate that this adjuvant synergy between GLA and CpG is independent of TRIF signaling, whereas TRIF is necessary for the adjuvant activity of GLA-SE in the absence of CpG.

  1. Bacillus subtilis spores expressing the VP28 antigen: a potential oral treatment to protect Litopenaeus vannamei against white spot syndrome.

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    Nguyen, Anh T V; Pham, Cuong K; Pham, Huong T T; Pham, Hang L; Nguyen, Anh H; Dang, Lua T; Huynh, Hong A; Cutting, Simon M; Phan, Tuan-Nghia

    2014-09-01

    The envelope protein VP28 of white spot syndrome virus (WSSV) is considered a candidate antigen for use in a potential vaccine to this important shrimp pathogen (the cause of white spot syndrome, WSS). Here, we used spores of Bacillus subtilis to display VP28 on the spore surface. Trials were conducted to evaluate their ability to protect shrimps against WSSV infection. The gene cotB-vp28 was integrated into the chromosome of the laboratory strain B. subtilis PY79, and expression of CotB-VP28 was detected by Western blotting and immunofluorescence. Expression of CotB-VP28 was equivalent to 1000 molecules per spore. PY79 and CotB-VP28 spores were mixed with pellets for feeding of whiteleg shrimps (Litopenaeus vannamei), followed by WSSV challenge. Superoxidase dismutase (SOD), phenoloxidase activities and mortality rates of the two shrimp groups were evaluated. Groups fed with PY79 and CotB-VP28 spores at day 7 had increased SOD activities of 29% and increased phenoloxidase activities of 15% and 33%, respectively, compared to those of the control group. Fourteen days postchallenge, 35% of vaccinated shrimps had died compared to 49% of those fed naked spores (PY79) and 66% untreated, unchallenged animals. These data suggest that spores expressing VP28 have potential as a prophylactic treatment of WSS.

  2. Enhanced protective efficacy of a chimeric form of the schistosomiasis vaccine antigen Sm-TSP-2.

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    Mark S Pearson

    Full Text Available The large extracellular loop of the Schistosoma mansoni tetraspanin, Sm-TSP-2, when fused to a thioredoxin partner and formulated with Freund's adjuvants, has been shown to be an efficacious vaccine against murine schistosomiasis. Moreover, Sm-TSP-2 is uniquely recognised by IgG(1 and IgG(3 from putatively resistant individuals resident in S. mansoni endemic areas in Brazil. In the present study, we expressed Sm-TSP-2 at high yield and in soluble form in E. coli without the need for a solubility enhancing fusion partner. We also expressed in E. coli a chimera called Sm-TSP-2/5B, which consisted of Sm-TSP-2 fused to the immunogenic 5B region of the hookworm aspartic protease and vaccine antigen, Na-APR-1. Sm-TSP-2 formulated with alum/CpG showed significant reductions in adult worm and liver egg burdens in two separate murine schistosomiasis challenge studies. Sm-TSP-2/5B afforded significantly greater protection than Sm-TSP-2 alone when both antigens were formulated with alum/CpG. The enhanced protection obtained with the chimeric fusion protein was associated with increased production of anti-Sm-TSP-2 antibodies and IL-4, IL-10 and IFN-γ from spleen cells of vaccinated animals. Sera from 666 individuals from Brazil who were infected with S. mansoni were screened for potentially deleterious IgE responses to Sm-TSP-2. Anti-Sm-TSP-2 IgE to this protein was not detected (also shown previously for Na-APR-1, suggesting that the chimeric antigen Sm-TSP-2/5B could be used to safely and effectively vaccinate people in areas where schistosomes and hookworms are endemic.

  3. Glyceradehyde-3-phosphate dehydrogenase as a suitable vaccine candidate for protection against bacterial and parasitic diseases.

    Science.gov (United States)

    Perez-Casal, Jose; Potter, Andrew A

    2016-02-17

    The enzyme glyceraldehyde-3-P-dehydrogenase (GAPDH) has been identified as having other properties in addition to its key role in glycolysis. The ability of GAPDH to bind to numerous extracellular matrices, modulation of host-immune responses, a role in virulence and surface location has prompted numerous investigators to postulate that GAPDH may be a good vaccine candidate for protection against numerous pathogens. Although immune responses against GAPDH have been described for many microorganisms, vaccines containing GAPDH have been successfully tested in few cases including those against the trematode-Schistosoma mansoni, the helminth-Enchinococcus multilocularis; the nematode filaria- Litomosoides sigmodontis; fish pathogens such as Aeromonas spp., Vibrio spp., Edwarsiella spp., and Streptococcus iniae; and environmental streptococci, namely, Streptococcus uberis and Streptococcus dysgalactiae. Before GAPDH-based vaccines are considered viable options for protection against numerous pathogens, we need to take into account the homology between the host and pathogen GAPDH proteins to prevent potential autoimmune reactions, thus protective GAPDH epitopes unique to the pathogen protein must be identified.

  4. Heterosubtypic protection against pathogenic human and avian influenza viruses via in vivo electroporation of synthetic consensus DNA antigens.

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    Dominick J Laddy

    Full Text Available BACKGROUND: The persistent evolution of highly pathogenic avian influenza (HPAI highlights the need for novel vaccination techniques that can quickly and effectively respond to emerging viral threats. We evaluated the use of optimized consensus influenza antigens to provide broad protection against divergent strains of H5N1 influenza in three animal models of mice, ferrets, and non-human primates. We also evaluated the use of in vivo electroporation to deliver these vaccines to overcome the immunogenicity barrier encountered in larger animal models of vaccination. METHODS AND FINDINGS: Mice, ferrets and non-human primates were immunized with consensus plasmids expressing H5 hemagglutinin (pH5HA, N1 neuraminidase (pN1NA, and nucleoprotein antigen (pNP. Dramatic IFN-gamma-based cellular immune responses to both H5 and NP, largely dependent upon CD8+ T cells were seen in mice. Hemaggutination inhibition titers classically associated with protection (>1:40 were seen in all species. Responses in both ferrets and macaques demonstrate the ability of synthetic consensus antigens to induce antibodies capable of inhibiting divergent strains of the H5N1 subtype, and studies in the mouse and ferret demonstrate the ability of synthetic consensus vaccines to induce protection even in the absence of such neutralizing antibodies. After challenge, protection from morbidity and mortality was seen in mice and ferrets, with significant reductions in viral shedding and disease progression seen in vaccinated animals. CONCLUSIONS: By combining several consensus influenza antigens with in vivo electroporation, we demonstrate that these antigens induce both protective cellular and humoral immune responses in mice, ferrets and non-human primates. We also demonstrate the ability of these antigens to protect from both morbidity and mortality in a ferret model of HPAI, in both the presence and absence of neutralizing antibody, which will be critical in responding to the

  5. MIC3, a novel cross-protective antigen expressed in Toxoplasma gondii and Neospora caninum.

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    Yang, Daoyu; Liu, Jing; Hao, Pan; Wang, Jing; Lei, Tao; Shan, Dan; Liu, Qun

    2015-10-01

    Microneme protein 3 (MIC3) is an important adhesion molecule expressed by Toxoplasma gondii and Neospora caninum that plays a crucial role in invasion. In our study, we found that recombinant TgMIC3 (rTgMIC3) was recognized by both T. gondii-reactive sera and hyper-immune serum against N. caninum. Polyclonal antibodies against TgMIC3 reacted with N. caninum by western blot and immunofluorescence assay (IFA). These results indicate that MIC3 is a novel cross-reactive antigen expressed in N. caninum and T. gondii. To evaluate the immune-protective effect of TgMIC3, we created the eukaryotic expression vector pcDNA3.1-TgMIC3, transfected this vector into HEK293T cells by lipofection, and evaluated TgMIC3 expression in HEK293T cells using western blot and IFA. Then, groups of BALB/c mice were immunized with recombinant TgMIC3 protein, pcDNA3.1-TgMIC3, or two-vaccine immunization. The mice were challenged with T. gondii RH or N. caninum Nc-1 tachyzoites 14 days after the final immunization. The survival time of T. gondii-infected mice was recorded, and the parasite burden in the brain of N. caninum-infected mice 30 days post-infection was measured using real-time PCR. The results demonstrated that mice immunized with TgMIC3-based vaccines elicited high antibody titers. After parasitic challenge, mice immunized with pcDNA-TgMIC3 exhibited prolonged survival when infected with T. gondii tachyzoites and a lower parasitic burden in the brains of mice challenged with N. caninum tachyzoites. These results demonstrate that TgMIC3 is a cross-protective antigen expressed in T. gondii and N. caninum and could elicit some protection against toxoplasmosis and neosporosis.

  6. A recombinant raccoon poxvirus vaccine expressing both Yersinia pestis F1 and truncated V antigens protects animals against lethal plague.

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    Rocke, Tonie E.; Kingstad-Bakke, B; Berlier, W; Osorio, J.E.

    2014-01-01

    In previous studies, we demonstrated in mice and prairie dogs that simultaneous administration of two recombinant raccoon poxviruses (rRCN) expressing Yersinia pestis antigens (F1 and V307-a truncated version of the V protein) provided superior protection against plague challenge compared to individual single antigen constructs. To reduce costs of vaccine production and facilitate implementation of a sylvatic plague vaccine (SPV) control program for prairie dogs, a dual antigen construct is more desirable. Here we report the construction and characterization of a novel RCN-vectored vaccine that simultaneously expresses both F1 and V307 antigens. This dual antigen vaccine provided similar levels of protection against plague in both mice and prairie dogs as compared to simultaneous administration of the two single antigen constructs and was also shown to protect mice against an F1 negative strain of Y. pestis.. The equivalent safety, immunogenicity and efficacy profile of the dual RCN-F1/V307 construct warrants further evaluation in field efficacy studies in sylvatic plague endemic areas.

  7. Cloning, expression and purification of binding domains of lethal factor and protective antigen of Bacillus anthracis in Escherichia coli and evaluation of their related murine antibody.

    Science.gov (United States)

    Rezaee, Mehdi; Honari, Hossein; Kooshk, Mohammad Reza Ashrafi

    2014-01-01

    Anthrax is common disease between human and animals caused by Bacillus anthracis. The cell binding domain of protective antigen (PAD4) and the binding domain of lethal factor (LFD1) have high immunogenicity potential and always were considered as a vaccine candidate against anthrax. The aims of this study are cloning and expressing of PAD4 and LFD1 in Escherichia coli, purification of the recombinant proteins and determination of their immunogenicity through evaluating of the relative produced polyclonal antibodies in mice. PAD4 and LFD1 genes were cloned in pET28a(+) vector and expressed in E. coli Bl21(DE3)PlysS. Expression and purification of the two recombinant proteins were confirmed by SDS-PAGE and Western blotting techniques. The PAD4 and LFD1 were purified using Ni(+)-NTA affinity chromatography (95-98 %), yielding 37.5 and 45 mg/l of culture, respectively. The antigens were injected three times into mice and production of relative antibodies was evaluated by ELISA test. The results showed that both PAD4 and LFD1 are immunogenic, but LFD1 has higher potential to stimulate Murine immune system. With regard to the high level of LFD1 and PAD4 expression and also significant increment in produced polyclonal antibodies, these recombinant proteins can be considered as a recombinant vaccine candidate against anthrax.

  8. Generation of protective immune response against anthrax by oral immunization with protective antigen plant-based vaccine.

    Science.gov (United States)

    Gorantala, Jyotsna; Grover, Sonam; Rahi, Amit; Chaudhary, Prerna; Rajwanshi, Ravi; Sarin, Neera Bhalla; Bhatnagar, Rakesh

    2014-04-20

    In concern with frequent recurrence of anthrax in endemic areas and inadvertent use of its spores as biological weapon, the development of an effective anthrax vaccine suitable for both human and veterinary needs is highly desirable. A simple oral delivery through expression in plant system could offer promising alternative to the current methods that rely on injectable vaccines extracted from bacterial sources. In the present study, we have expressed protective antigen (PA) gene in Indian mustard by Agrobacterium-mediated transformation and in tobacco by plastid transformation. Putative transgenic lines were verified for the presence of transgene and its expression by molecular analysis. PA expressed in transgenic lines was biologically active as evidenced by macrophage lysis assay. Intraperitoneal (i.p.) and oral immunization with plant PA in murine model indicated high serum PA specific IgG and IgA antibody titers. PA specific mucosal immune response was noted in orally immunized groups. Further, antibodies indicated lethal toxin neutralizing potential in-vitro and conferred protection against in-vivo toxin challenge. Oral immunization experiments demonstrated generation of immunoprotective response in mice. Thus, our study examines the feasibility of oral PA vaccine expressed in an edible plant system against anthrax.

  9. Multivalent Chromosomal Expression of the Clostridium botulinum Serotype A Neurotoxin Heavy-Chain Antigen and the Bacillus anthracis Protective Antigen in Lactobacillus acidophilus

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    Klaenhammer, Todd R.

    2016-01-01

    ABSTRACT Clostridium botulinum and Bacillus anthracis produce potent toxins that cause severe disease in humans. New and improved vaccines are needed for both of these pathogens. For mucosal vaccine delivery using lactic acid bacteria, chromosomal expression of antigens is preferred over plasmid-based expression systems, as chromosomal expression circumvents plasmid instability and the need for antibiotic pressure. In this study, we constructed three strains of Lactobacillus acidophilus NCFM expressing from the chromosome (i) the nontoxic host receptor-binding domain of the heavy chain of Clostridium botulinum serotype A neurotoxin (BoNT/A-Hc), (ii) the anthrax protective antigen (PA), and (iii) both the BoNT/A-Hc and the PA. The BoNT/A-Hc vaccine cassette was engineered to contain the signal peptide from the S-layer protein A from L. acidophilus and a dendritic-cell-targeting peptide. A chromosomal region downstream of lba0889 carrying a highly expressed enolase gene was selected for insertion of the vaccine cassettes. Western blot analysis confirmed the heterologous expression of the two antigens from plasmid and chromosome locations. Stability assays demonstrated loss of the vaccine cassettes from expression plasmids without antibiotic maintenance. RNA sequencing showed high expression of each antigen and that insertion of the vaccine cassettes had little to no effect on the transcription of other genes in the chromosome. This study demonstrated that chromosomal integrative recombinant strains are promising vaccine delivery vehicles when targeted into high-expression chromosomal regions. Levels of expression match high-copy-number plasmids and eliminate the requirement for antibiotic selective maintenance of recombinant plasmids. IMPORTANCE Clostridium botulinum and Bacillus anthracis produce potent neurotoxins that pose a biochemical warfare concern; therefore, effective vaccines against these bacteria are required. Chromosomal expression of antigens is

  10. Cancer testis antigen vaccination affords long-term protection in a murine model of ovarian cancer.

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    Maurizio Chiriva-Internati

    Full Text Available Sperm protein (Sp17 is an attractive target for ovarian cancer (OC vaccines because of its over-expression in primary as well as in metastatic lesions, at all stages of the disease. Our studies suggest that a Sp17-based vaccine can induce an enduring defense against OC development in C57BL/6 mice with ID8 cells, following prophylactic and therapeutic treatments. This is the first time that a mouse counterpart of a cancer testis antigen (Sp17 was shown to be expressed in an OC mouse model, and that vaccination against this antigen significantly controlled tumor growth. Our study shows that the CpG-adjuvated Sp17 vaccine overcomes the issue of immunologic tolerance, the major barrier to the development of effective immunotherapy for OC. Furthermore, this study provides a better understanding of OC biology by showing that Th-17 cells activation and contemporary immunosuppressive T-reg cells inhibition is required for vaccine efficacy. Taken together, these results indicate that prophylactic and therapeutic vaccinations can induce long-standing protection against OC and delay tumor growth, suggesting that this strategy may provide additional treatments of human OC and the prevention of disease onset in women with a family history of OC.

  11. Intravacuolar Membranes Regulate CD8 T Cell Recognition of Membrane-Bound Toxoplasma gondii Protective Antigen

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    Jodie Lopez

    2015-12-01

    Full Text Available Apicomplexa parasites such as Toxoplasma gondii target effectors to and across the boundary of their parasitophorous vacuole (PV, resulting in host cell subversion and potential presentation by MHC class I molecules for CD8 T cell recognition. The host-parasite interface comprises the PV limiting membrane and a highly curved, membranous intravacuolar network (IVN of uncertain function. Here, using a cell-free minimal system, we dissect how membrane tubules are shaped by the parasite effectors GRA2 and GRA6. We show that membrane association regulates access of the GRA6 protective antigen to the MHC I pathway in infected cells. Although insertion of GRA6 in the PV membrane is key for immunogenicity, association of GRA6 with the IVN limits presentation and curtails GRA6-specific CD8 responses in mice. Thus, membrane deformations of the PV regulate access of antigens to the MHC class I pathway, and the IVN may play a role in immune modulation.

  12. Breadth of humoral response and antigenic targets of sporozoite-inhibitory antibodies associated with sterile protection induced by controlled human malaria infection

    Science.gov (United States)

    Peng, Kaitian; Goh, Yun Shan; Siau, Anthony; Franetich, Jean-François; Chia, Wan Ni; Ong, Alice Soh Meoy; Malleret, Benoit; Wu, Ying Ying; Snounou, Georges; Hermsen, Cornelus C.; Adams, John H.; Mazier, Dominique; Preiser, Peter R.; Sauerwein, Robert W.; Grüner, Anne-Charlotte; Rénia, Laurent

    2017-01-01

    The development of an effective malaria vaccine has remained elusive even until today. This is due to our incomplete understanding of the immune mechanisms that confer and/or correlate with protection. Human volunteers have been protected experimentally from a subsequent challenge by immunization with Plasmodium falciparum sporozoites under drug cover. Here, we demonstrate that sera from the protected individuals contain neutralizing antibodies against the pre erythrocytic stage. To identify the antigen(s) recognized by these antibodies, a newly developed library of P. falciparum antigens was screened with the neutralizing sera. Antibodies from protected individuals recognized a broad antigenic repertoire of which three antigens, PfMAEBL, PfTRAP and PfSEA1 were recognized by most protected individuals. As a proof of principle, we demonstrated that anti-PfMAEBL antibodies block liver stage development in human hepatocytes. Thus, these antigens identified are promising targets for vaccine development against malaria. PMID:27130708

  13. The Vaccine Candidate Vibrio cholerae 638 Is Protective against Cholera in Healthy Volunteers

    Science.gov (United States)

    García, Luis; Jidy, Manuel Díaz; García, Hilda; Rodríguez, Boris L.; Fernández, Roberto; Año, Gemma; Cedré, Bárbara; Valmaseda, Tania; Suzarte, Edith; Ramírez, Margarita; Pino, Yadira; Campos, Javier; Menéndez, Jorge; Valera, Rodrigo; González, Daniel; González, Irma; Pérez, Oliver; Serrano, Teresita; Lastre, Miriam; Miralles, Fernando; del Campo, Judith; Maestre, Jorge Luis; Pérez, José Luis; Talavera, Arturo; Pérez, Antonio; Marrero, Karen; Ledón, Talena; Fando, Rafael

    2005-01-01

    Vibrio cholerae 638 is a living candidate cholera vaccine strain attenuated by deletion of the CTXΦ prophage from C7258 (O1, El Tor Ogawa) and by insertion of the Clostridium thermocellum endoglucanase A gene into the hemagglutinin/protease coding sequence. This vaccine candidate was previously found to be well tolerated and immunogenic in volunteers. This article reports a randomized, double-blind, placebo-controlled trial conducted to test short-term protection conferred by 638 against subsequent V. cholerae infection and disease in volunteers in Cuba. A total of 45 subjects were enrolled and assigned to receive vaccine or placebo. The vaccine contained 109 CFU of freshly harvested 638 buffered with 1.3% NaHCO3, while the placebo was buffer alone. After vaccine but not after placebo intake, 96% of volunteers had at least a fourfold increase in vibriocidal antibody titers, and 50% showed a doubling of at least the lipopolysaccharide-specific immunoglobulin A titers in serum. At 1 month after vaccination, five volunteers from the vaccine group and five from the placebo group underwent an exploratory challenge study with 109 CFU of ΔCTXΦ attenuated mutant strain V. cholerae 81. Only two volunteers from the vaccine group shed strain 81 in their feces, but none of them experienced diarrhea; in the placebo group, all volunteers excreted the challenge strain, and three had reactogenic diarrhea. An additional 12 vaccinees and 9 placebo recipients underwent challenge with 7 × 105 CFU of virulent strain V. cholerae 3008 freshly harvested from a brain heart infusion agar plate and buffered with 1.3% NaHCO3. Three volunteers (25%) from the vaccine group and all from the placebo group shed the challenge agent in their feces. None of the 12 vaccinees but 7 volunteers from the placebo group had diarrhea, and 2 of the latter exhibited severe cholera (>5,000 g of diarrheal stool). These results indicate that at 1 month after ingestion of a single oral dose (109 CFU) of strain

  14. Identification of Leishmania infantum chagasi proteins in urine of patients with visceral leishmaniasis: a promising antigen discovery approach of vaccine candidates.

    Science.gov (United States)

    Kashino, S S; Abeijon, C; Qin, L; Kanunfre, K A; Kubrusly, F S; Silva, F O; Costa, D L; Campos, D; Costa, C H N; Raw, I; Campos-Neto, A

    2012-07-01

    Visceral leishmaniasis (VL) is a serious lethal parasitic disease caused by Leishmania donovani in Asia and by Leishmania infantum chagasi in southern Europe and South America. VL is endemic in 47 countries with an annual incidence estimated to be 500,000 cases. This high incidence is due in part to the lack of an efficacious vaccine. Here, we introduce an innovative approach to directly identify parasite vaccine candidate antigens that are abundantly produced in vivo in humans with VL. We combined RP-HPLC and mass spectrometry and categorized three L. infantum chagasi proteins, presumably produced in spleen, liver and bone marrow lesions and excreted in the patients' urine. Specifically, these proteins were the following: Li-isd1 (XP_001467866.1), Li-txn1 (XP_001466642.1) and Li-ntf2 (XP_001463738.1). Initial vaccine validation studies were performed with the rLi-ntf2 protein produced in Escherichia coli mixed with the adjuvant BpMPLA-SE. This formulation stimulated potent Th1 response in BALB/c mice. Compared to control animals, mice immunized with Li-ntf2+ BpMPLA-SE had a marked parasite burden reduction in spleens at 40 days post-challenge with virulent L. infantum chagasi. These results strongly support the proposed antigen discovery strategy of vaccine candidates to VL and opens novel possibilities for vaccine development to other serious infectious diseases.

  15. Biophysical and formulation studies of the Schistosoma mansoni TSP-2 extracellular domain recombinant protein, a lead vaccine candidate antigen for intestinal schistosomiasis.

    Science.gov (United States)

    Cheng, Weiqiang; Curti, Elena; Rezende, Wanderson C; Kwityn, Clifford; Zhan, Bin; Gillespie, Portia; Plieskatt, Jordan; Joshi, Sangeeta B; Volkin, David B; Hotez, Peter J; Middaugh, C Russell; Bottazzi, Maria Elena

    2013-11-01

    A candidate vaccine to prevent human schistosomiasis is under development. The vaccine is comprised of a recombinant 9 kDa antigen protein corresponding to the large extracellular domain of a tetraspanin surface antigen protein of Schistosoma mansoni, Sm-TSP-2. Here, we describe the biophysical profile of the purified, recombinant Sm-TSP-2 produced in the yeast PichiaPink, which in preclinical studies in mice was shown to be an effective vaccine against intestinal schistosomiasis. Biophysical techniques including circular dichroism, intrinsic and extrinsic fluorescence and light scattering were employed to generate an empirical phase diagram, a color based map of the physical stability of the vaccine antigen over a wide range of temperatures and pH. From these studies a pH range of 6.0-8.0 was determined to be optimal for maintaining the stability and conformation of the protein at temperatures up to 25 °C. Sorbitol, sucrose and trehalose were selected as excipients that prevented physical degradation during storage. The studies described here provide guidance for maximizing the stability of soluble recombinant Sm-TSP-2 in preparation of its further development as a vaccine.

  16. 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.

  17. Recombinant Salmonella Expressing Burkholderia mallei LPS O Antigen Provides Protection in a Murine Model of Melioidosis and Glanders.

    Science.gov (United States)

    Moustafa, Dina A; Scarff, Jennifer M; Garcia, Preston P; Cassidy, Sara K B; DiGiandomenico, Antonio; Waag, David M; Inzana, Thomas J; Goldberg, Joanna B

    2015-01-01

    Burkholderia pseudomallei and Burkholderia mallei are the etiologic agents of melioidosis and glanders, respectively. These bacteria are highly infectious via the respiratory route and can cause severe and often fatal diseases in humans and animals. Both species are considered potential agents of biological warfare; they are classified as category B priority pathogens. Currently there are no human or veterinary vaccines available against these pathogens. Consequently efforts are directed towards the development of an efficacious and safe vaccine. Lipopolysaccharide (LPS) is an immunodominant antigen and potent stimulator of host immune responses. B. mallei express LPS that is structurally similar to that expressed by B. pseudomallei, suggesting the possibility of constructing a single protective vaccine against melioidosis and glanders. Previous studies of others have shown that antibodies against B. mallei or B. pseudomallei LPS partially protect mice against subsequent lethal virulent Burkholderia challenge. In this study, we evaluated the protective efficacy of recombinant Salmonella enterica serovar Typhimurium SL3261 expressing B. mallei O antigen against lethal intranasal infection with Burkholderia thailandensis, a surrogate for biothreat Burkholderia spp. in a murine model that mimics melioidosis and glanders. All vaccine-immunized mice developed a specific antibody response to B. mallei and B. pseudomallei O antigen and to B. thailandensis and were significantly protected against challenge with a lethal dose of B. thailandensis. These results suggest that live-attenuated SL3261 expressing B. mallei O antigen is a promising platform for developing a safe and effective vaccine.

  18. Recombinant Salmonella Expressing Burkholderia mallei LPS O Antigen Provides Protection in a Murine Model of Melioidosis and Glanders.

    Directory of Open Access Journals (Sweden)

    Dina A Moustafa

    Full Text Available Burkholderia pseudomallei and Burkholderia mallei are the etiologic agents of melioidosis and glanders, respectively. These bacteria are highly infectious via the respiratory route and can cause severe and often fatal diseases in humans and animals. Both species are considered potential agents of biological warfare; they are classified as category B priority pathogens. Currently there are no human or veterinary vaccines available against these pathogens. Consequently efforts are directed towards the development of an efficacious and safe vaccine. Lipopolysaccharide (LPS is an immunodominant antigen and potent stimulator of host immune responses. B. mallei express LPS that is structurally similar to that expressed by B. pseudomallei, suggesting the possibility of constructing a single protective vaccine against melioidosis and glanders. Previous studies of others have shown that antibodies against B. mallei or B. pseudomallei LPS partially protect mice against subsequent lethal virulent Burkholderia challenge. In this study, we evaluated the protective efficacy of recombinant Salmonella enterica serovar Typhimurium SL3261 expressing B. mallei O antigen against lethal intranasal infection with Burkholderia thailandensis, a surrogate for biothreat Burkholderia spp. in a murine model that mimics melioidosis and glanders. All vaccine-immunized mice developed a specific antibody response to B. mallei and B. pseudomallei O antigen and to B. thailandensis and were significantly protected against challenge with a lethal dose of B. thailandensis. These results suggest that live-attenuated SL3261 expressing B. mallei O antigen is a promising platform for developing a safe and effective vaccine.

  19. Induction of partial protection against infection with Toxoplasma gondii genotype II by DNA vaccination with recombinant chimeric tachyzoite antigens

    DEFF Research Database (Denmark)

    Rosenberg, Carina Agerbo; De Craeye, S.; Jongert, E.

    2009-01-01

    complications. Although several strategies have been suggested for making a vaccine, none is currently available. Here, we investigate the protection conferred by DNA vaccination with two constructs, pcEC2 (MIC2-MIC3-SAG1) and pcEC3 (GRA3-GRA7-M2AP), encoding chimeric proteins containing multiple antigenic...

  20. Tumor-associated antigens identified by mRNA expression profiling induce protective anti-tumor immunity

    DEFF Research Database (Denmark)

    Mathiassen, Søren; Lauemøller, S L; Ruhwald, Morten;

    2001-01-01

    to identify TAA, mice were immunized with mixtures of peptides representing putative cytotoxic T cell epitopes derived from one of the gene products. Indeed, such immunized mice were partially protected against subsequent tumor challenge. Despite being immunized with bona fide self antigens, no clinical signs...

  1. CD4+ T Cells Recognizing PE/PPE Antigens Directly or via Cross Reactivity Are Protective against Pulmonary Mycobacterium tuberculosis Infection.

    Science.gov (United States)

    Sayes, Fadel; Pawlik, Alexandre; Frigui, Wafa; Gröschel, Matthias I; Crommelynck, Samuel; Fayolle, Catherine; Cia, Felipe; Bancroft, Gregory J; Bottai, Daria; Leclerc, Claude; Brosch, Roland; Majlessi, Laleh

    2016-07-01

    Mycobacterium tuberculosis (Mtb), possesses at least three type VII secretion systems, ESX-1, -3 and -5 that are actively involved in pathogenesis and host-pathogen interaction. We recently showed that an attenuated Mtb vaccine candidate (Mtb Δppe25-pe19), which lacks the characteristic ESX-5-associated pe/ppe genes, but harbors all other components of the ESX-5 system, induces CD4+ T-cell immune responses against non-esx-5-associated PE/PPE protein homologs. These T cells strongly cross-recognize the missing esx-5-associated PE/PPE proteins. Here, we characterized the fine composition of the functional cross-reactive Th1 effector subsets specific to the shared PE/PPE epitopes in mice immunized with the Mtb Δppe25-pe19 vaccine candidate. We provide evidence that the Mtb Δppe25-pe19 strain, despite its significant attenuation, is comparable to the WT Mtb strain with regard to: (i) its antigenic repertoire related to the different ESX systems, (ii) the induced Th1 effector subset composition, (iii) the differentiation status of the Th1 cells induced, and (iv) its particular features at stimulating the innate immune response. Indeed, we found significant contribution of PE/PPE-specific Th1 effector cells in the protective immunity against pulmonary Mtb infection. These results offer detailed insights into the immune mechanisms underlying the remarkable protective efficacy of the live attenuated Mtb Δppe25-pe19 vaccine candidate, as well as the specific potential of PE/PPE proteins as protective immunogens.

  2. Superoxide dismutase SodB is a protective antigen against Campylobacter jejuni colonisation in chickens.

    Science.gov (United States)

    Chintoan-Uta, Cosmin; Cassady-Cain, Robin L; Al-Haideri, Halah; Watson, Eleanor; Kelly, David J; Smith, David G E; Sparks, Nick H C; Kaiser, Pete; Stevens, Mark P

    2015-11-17

    Campylobacter is the leading cause of foodborne diarrhoeal illness in the developed world and consumption or handling of contaminated poultry meat is the principal source of infection. Strategies to control Campylobacter in broilers prior to slaughter are urgently required and are predicted to limit the incidence of human campylobacteriosis. Towards this aim, a purified recombinant subunit vaccine based on the superoxide dismutase (SodB) protein of C. jejuni M1 was developed and tested in White Leghorn birds. Birds were vaccinated on the day of hatch and 14 days later with SodB fused to glutathione S-transferase (GST) or purified GST alone. Birds were challenged with C. jejuni M1 at 28 days of age and caecal Campylobacter counts determined at weekly intervals. Across three independent trials, the vaccine induced a statistically significant 1 log10 reduction in caecal Campylobacter numbers in vaccinated birds compared to age-matched GST-vaccinated controls. Significant induction of antigen-specific serum IgY was detected in all vaccinated birds, however the magnitude and timing of SodB-specific IgY did not correlate with lower numbers of C. jejuni. Antibodies from SodB-vaccinated chickens detected the protein in the periplasm and not membrane fractions or on the bacterial surface, suggesting that the protection observed may not be strictly antibody-mediated. SodB may be useful as a constituent of vaccines for control of C. jejuni infection in broiler birds, however modest protection was observed late relative to the life of broiler birds and further studies are required to potentiate the magnitude and timing of protection.

  3. Antibody to a conserved antigenic target is protective against diverse prokaryotic and eukaryotic pathogens.

    Science.gov (United States)

    Cywes-Bentley, Colette; Skurnik, David; Zaidi, Tanweer; Roux, Damien; Deoliveira, Rosane B; Garrett, Wendy S; Lu, Xi; O'Malley, Jennifer; Kinzel, Kathryn; Zaidi, Tauqeer; Rey, Astrid; Perrin, Christophe; Fichorova, Raina N; Kayatani, Alexander K K; Maira-Litràn, Tomas; Gening, Marina L; Tsvetkov, Yury E; Nifantiev, Nikolay E; Bakaletz, Lauren O; Pelton, Stephen I; Golenbock, Douglas T; Pier, Gerald B

    2013-06-11

    Microbial capsular antigens are effective vaccines but are chemically and immunologically diverse, resulting in a major barrier to their use against multiple pathogens. A β-(1→6)-linked poly-N-acetyl-d-glucosamine (PNAG) surface capsule is synthesized by four proteins encoded in genetic loci designated intercellular adhesion in Staphylococcus aureus or polyglucosamine in selected Gram-negative bacterial pathogens. We report that many microbial pathogens lacking an identifiable intercellular adhesion or polyglucosamine locus produce PNAG, including Gram-positive, Gram-negative, and fungal pathogens, as well as protozoa, e.g., Trichomonas vaginalis, Plasmodium berghei, and sporozoites and blood-stage forms of Plasmodium falciparum. Natural antibody to PNAG is common in humans and animals and binds primarily to the highly acetylated glycoform of PNAG but is not protective against infection due to lack of deposition of complement opsonins. Polyclonal animal antibody raised to deacetylated glycoforms of PNAG and a fully human IgG1 monoclonal antibody that both bind to native and deacetylated glycoforms of PNAG mediated complement-dependent opsonic or bactericidal killing and protected mice against local and/or systemic infections by Streptococcus pyogenes, Streptococcus pneumoniae, Listeria monocytogenes, Neisseria meningitidis serogroup B, Candida albicans, and P. berghei ANKA, and against colonic pathology in a model of infectious colitis. PNAG is also a capsular polysaccharide for Neisseria gonorrhoeae and nontypable Hemophilus influenzae, and protects cells from environmental stress. Vaccination targeting PNAG could contribute to immunity against serious and diverse prokaryotic and eukaryotic pathogens, and the conserved production of PNAG suggests that it is a critical factor in microbial biology.

  4. Superoxide dismutase SodB is a protective antigen against Campylobacter jejuni colonisation in chickens

    Science.gov (United States)

    Chintoan-Uta, Cosmin; Cassady-Cain, Robin L.; Al-Haideri, Halah; Watson, Eleanor; Kelly, David J.; Smith, David G.E.; Sparks, Nick H.C.; Kaiser, Pete; Stevens, Mark P.

    2015-01-01

    Campylobacter is the leading cause of foodborne diarrhoeal illness in the developed world and consumption or handling of contaminated poultry meat is the principal source of infection. Strategies to control Campylobacter in broilers prior to slaughter are urgently required and are predicted to limit the incidence of human campylobacteriosis. Towards this aim, a purified recombinant subunit vaccine based on the superoxide dismutase (SodB) protein of C. jejuni M1 was developed and tested in White Leghorn birds. Birds were vaccinated on the day of hatch and 14 days later with SodB fused to glutathione S-transferase (GST) or purified GST alone. Birds were challenged with C. jejuni M1 at 28 days of age and caecal Campylobacter counts determined at weekly intervals. Across three independent trials, the vaccine induced a statistically significant 1 log10 reduction in caecal Campylobacter numbers in vaccinated birds compared to age-matched GST-vaccinated controls. Significant induction of antigen-specific serum IgY was detected in all vaccinated birds, however the magnitude and timing of SodB-specific IgY did not correlate with lower numbers of C. jejuni. Antibodies from SodB-vaccinated chickens detected the protein in the periplasm and not membrane fractions or on the bacterial surface, suggesting that the protection observed may not be strictly antibody-mediated. SodB may be useful as a constituent of vaccines for control of C. jejuni infection in broiler birds, however modest protection was observed late relative to the life of broiler birds and further studies are required to potentiate the magnitude and timing of protection. PMID:26458797

  5. Human leukocyte antigen E contributes to protect tumor cells from lysis by natural killer cells.

    Science.gov (United States)

    Lo Monaco, Elisa; Tremante, Elisa; Cerboni, Cristina; Melucci, Elisa; Sibilio, Leonardo; Zingoni, Alessandra; Nicotra, Maria Rita; Natali, Pier Giorgio; Giacomini, Patrizio

    2011-09-01

    The nonclassic class I human leukocyte antigen E (HLA-E) molecule engages the inhibitory NKG2A receptor on several cytotoxic effectors, including natural killer (NK) cells. Its tissue distribution was claimed to be wider in normal than in neoplastic tissues, and surface HLA-E was undetectable in most tumor cell lines. Herein, these issues were reinvestigated taking advantage of HLA-E-specific antibodies, immunohistochemistry, and biochemical methods detecting intracellular and surface HLA-E regardless of conformation. Contrary to published evidence, HLA-E was detected in a few normal epithelia and in a large fraction (approximately 1/3) of solid tumors, including those derived from HLA-E-negative/low-normal counterparts. Remarkably, HLA-E was detected in 30 of 30 tumor cell lines representative of major lymphoid and nonlymphoid lineages, and in 11 of 11, it was surface-expressed, although in a conformation poorly reactive with commonly used antibodies. Coexpression of HLA-E and HLA class I ligand donors was not required for surface expression but was associated with NKG2A-mediated protection from lysis by the cytotoxic cell line NKL and polyclonal NK cells from healthy donors, as demonstrated by antibody-mediated relief of protection in 10% to 20% of the tested target-effector combinations. NKG2A-mediated protection of additional targets became evident on NK effector blocking with antibodies to activating receptors (DNAM-1, natural cytotoxicity receptors, and NKG2D). Thus, initial evidence that the long-elusive HLA-E molecule is enhanced by malignant transformation and is functional in tumor cells is presented here, although its importance and precise functional role remain to be addressed in the context of a general understanding of the NK ligand-receptor network.

  6. Human Leukocyte Antigen E Contributes to Protect Tumor Cells from Lysis by Natural Killer Cells

    Directory of Open Access Journals (Sweden)

    Elisa Lo Monaco

    2011-09-01

    Full Text Available The nonclassic class I human leukocyte antigen E (HLA-E molecule engages the inhibitory NKG2A receptor on several cytotoxic effectors, including natural killer (NK cells. Its tissue distribution was claimed to be wider in normal than in neoplastic tissues, and surface HLA-E was undetectable in most tumor cell lines. Herein, these issues were reinvestigated taking advantage of HLA-E-specific antibodies, immunohistochemistry, and biochemical methods detecting intracellular and surface HLA-E regardless of conformation. Contrary to published evidence, HLA-E was detected in a few normal epithelia and in a large fraction (approximately 1/3 of solid tumors, including those derived from HLA-E-negative/low-normal counterparts. Remarkably, HLA-E was detected in 30 of 30 tumor cell lines representative of major lymphoid and nonlymphoid lineages, and in 11 of 11, it was surface-expressed, although in a conformation poorly reactive with commonly used antibodies. Coexpression of HLA-E and HLA class I ligand donors was not required for surface expression but was associated with NKG2A-mediated protection from lysis by the cytotoxic cell line NKL and polyclonal NK cells from healthy donors, as demonstrated by antibody-mediated relief of protection in 10% to 20% of the tested target-effector combinations. NKG2A-mediated protection of additional targets became evident on NK effector blocking with antibodies to activating receptors (DNAM-1, natural cytotoxicity receptors, and NKG2D. Thus, initial evidence that the long-elusive HLA-E molecule is enhanced by malignant transformation and is functional in tumor cells is presented here, although its importance and precise functional role remain to be addressed in the context of a general understanding of the NK ligand-receptor network.

  7. Human Leukocyte Antigen E Contributes to Protect Tumor Cells from Lysis by Natural Killer Cells12

    Science.gov (United States)

    Monaco, Elisa Lo; Tremante, Elisa; Cerboni, Cristina; Melucci, Elisa; Sibilio, Leonardo; Zingoni, Alessandra; Nicotra, Maria Rita; Natali, Pier Giorgio; Giacomini, Patrizio

    2011-01-01

    The nonclassic class I human leukocyte antigen E (HLA-E) molecule engages the inhibitory NKG2A receptor on several cytotoxic effectors, including natural killer (NK) cells. Its tissue distribution was claimed to be wider in normal than in neoplastic tissues, and surface HLA-E was undetectable in most tumor cell lines. Herein, these issues were reinvestigated taking advantage of HLA-E-specific antibodies, immunohistochemistry, and biochemical methods detecting intracellular and surface HLA-E regardless of conformation. Contrary to published evidence, HLA-E was detected in a few normal epithelia and in a large fraction (approximately 1/3) of solid tumors, including those derived from HLA-E-negative/low-normal counterparts. Remarkably, HLA-E was detected in 30 of 30 tumor cell lines representative of major lymphoid and nonlymphoid lineages, and in 11 of 11, it was surface-expressed, although in a conformation poorly reactive with commonly used antibodies. Coexpression of HLA-E and HLA class I ligand donors was not required for surface expression but was associated with NKG2A-mediated protection from lysis by the cytotoxic cell line NKL and polyclonal NK cells from healthy donors, as demonstrated by antibody-mediated relief of protection in 10% to 20% of the tested target-effector combinations. NKG2A-mediated protection of additional targets became evident on NK effector blocking with antibodies to activating receptors (DNAM-1, natural cytotoxicity receptors, and NKG2D). Thus, initial evidence that the long-elusive HLA-E molecule is enhanced by malignant transformation and is functional in tumor cells is presented here, although its importance and precise functional role remain to be addressed in the context of a general understanding of the NK ligand-receptor network. PMID:21969815

  8. Hepatitis C Virus Subtype 3a Envelope Protein 1 Binding with Human Leukocyte Antigen Class I Types of Pakistani Population: Candidate Epitopes for Synthetic Peptide Vaccine

    Directory of Open Access Journals (Sweden)

    Hamid Nawaz-Tipu

    2015-10-01

    Full Text Available The object of this cross sectional study was to determine the HCV subtype 3a envelope protein binding affinity with Human Leukocyte Antigen. Envelope 1 (E1 protein is one of the structural proteins responsible for entering the cells through the receptors. The binding affinity of E1 protein epitopes to the selected Human Leukocyte Antigen (HLA class I alleles was investigated using the computer-based tools. These prediction tools were also used to design the synthetic vaccine’s candidate epitopes and to identify the individuals/populations who are likely to be responder to those vaccines.The mean frequency of HLA I antigens in Pakistani population was calculated. Threealleles each from HLA A and B were selected. E1 protein sequence extracted from HCV 3a isolates was retrieved and twenty-four sequences of it were selected. NetMHCcons 1.0 server was used to determine the binding affinities of HLA alleles to the epitope sequences of 10 amino acids in length.A02, A03, A11, A24, A33, B08, B13, B15, B35 and B40 were the first five antigens moreprevalent in Pakistan each from HLA A and HLA B.. We did not find any binding affinity between HLA A*201, B*1501 and B*4001 and epitopes from E1 sequences in a threshold of50 nM. Totally five various epitopes derived from different isolates were characterized.The prediction of HLA-E1 epitope specific bindings and the forthcoming response can be a useful bioinformatics tool to uncover the right synthetic peptides for vaccine design purposes.

  9. Hepatitis C Virus Subtype 3a Envelope Protein 1 Binding with Human Leukocyte Antigen Class I Types of Pakistani Population: Candidate Epitopes for Synthetic Peptide Vaccine.

    Science.gov (United States)

    Nawaz-Tipu, Hamid

    2015-10-01

    The object of this cross sectional study was to determine the HCV subtype 3a envelope protein binding affinity with Human Leukocyte Antigen. Envelope 1 (E1) protein is one of the structural proteins responsible for entering the cells through the receptors. The binding affinity of E1 protein epitopes to the selected Human Leukocyte Antigen (HLA) class I alleles was investigated using the computer-based tools. These prediction tools were also used to design the synthetic vaccine's candidate epitopes and to identify the individuals/populations who are likely to be responder to those vaccines.The mean frequency of HLA I antigens in Pakistani population was calculated. Three alleles each from HLA A and B were selected. E1 protein sequence extracted from HCV 3a isolates was retrieved and twenty-four sequences of it were selected. NetMHCcons 1.0 server was used to determine the binding affinities of HLA alleles to the epitope sequences of 10 amino acids in length.A02, A03, A11, A24, A33, B08, B13, B15, B35 and B40 were the first five antigens more prevalent in Pakistan each from HLA A and HLA B.. We did not find any binding affinity between HLA A*201, B*1501 and B*4001 and epitopes from E1 sequences in a threshold of 50 nM. Totally five various epitopes derived from different isolates were characterized.The prediction of HLA-E1 epitope specific bindings and the forthcoming response can be a useful bioinformatics tool to uncover the right synthetic peptides for vaccine design purposes.

  10. Construction of a Salmonella Gallinarum ghost as a novel inactivated vaccine candidate and its protective efficacy against fowl typhoid in chickens

    Directory of Open Access Journals (Sweden)

    Chaudhari Atul A

    2012-05-01

    Full Text Available Abstract In order to develop a novel, safe and immunogenic fowl typhoid (FT vaccine candidate, a Salmonella Gallinarum ghost with controlled expression of the bacteriophage PhiX174 lysis gene E was constructed using pMMP99 plasmid in this study. The formation of the Salmonella Gallinarum ghost with tunnel formation and loss of cytoplasmic contents was observed by scanning electron microscopy and transmission electron microscopy. No viable cells were detectable 24 h after the induction of gene E expression by an increase in temperature from 37 °C to 42 °C. The safety and protective efficacy of the Salmonella Gallinarum ghost vaccine was tested in chickens that were divided into four groups: group A (non-immunized control, group B (orally immunized, group C (subcutaneously immunized and group D (intramuscularly immunized. The birds were immunized at day 7 of age. None of the immunized animals showed any adverse reactions such as abnormal behavior, mortality, or signs of FT such as anorexia, depression, or diarrhea. These birds were subsequently challenged with a virulent Salmonella Gallinarum strain at 3 weeks post-immunization (wpi. Significant protection against the virulent challenge was observed in all immunized groups based on mortality and post-mortem lesions compared to the non-immunized control group. In addition, immunization with the Salmonella Gallinarum ghosts induced significantly high systemic IgG response in all immunized groups. Among the groups, orally-vaccinated group B showed significantly higher levels of secreted IgA. A potent antigen-specific lymphocyte activation response along with significantly increased percentages of CD4+ and CD8+ T lymphocytes found in all immunized groups clearly indicate the induction of cellular immune responses. Overall, these findings suggest that the newly constructed Salmonella Gallinarum ghost appears to be a safe, highly immunogenic, and efficient non-living bacterial vaccine

  11. Coordinated activation of candidate proto-oncogenes and cancer testes antigens via promoter demethylation in head and neck cancer and lung cancer.

    Directory of Open Access Journals (Sweden)

    Ian M Smith

    Full Text Available BACKGROUND: Epigenetic alterations have been implicated in the pathogenesis of solid tumors, however, proto-oncogenes activated by promoter demethylation have been sporadically reported. We used an integrative method to analyze expression in primary head and neck squamous cell carcinoma (HNSCC and pharmacologically demethylated cell lines to identify aberrantly demethylated and expressed candidate proto-oncogenes and cancer testes antigens in HNSCC. METHODOLOGY/PRINCIPAL FINDINGS: We noted coordinated promoter demethylation and simultaneous transcriptional upregulation of proto-oncogene candidates with promoter homology, and phylogenetic footprinting of these promoters demonstrated potential recognition sites for the transcription factor BORIS. Aberrant BORIS expression correlated with upregulation of candidate proto-oncogenes in multiple human malignancies including primary non-small cell lung cancers and HNSCC, induced coordinated proto-oncogene specific promoter demethylation and expression in non-tumorigenic cells, and transformed NIH3T3 cells. CONCLUSIONS/SIGNIFICANCE: Coordinated, epigenetic unmasking of multiple genes with growth promoting activity occurs in aerodigestive cancers, and BORIS is implicated in the coordinated promoter demethylation and reactivation of epigenetically silenced genes in human cancers.

  12. Immunity to intracellular Salmonella depends on surface-associated antigens.

    Directory of Open Access Journals (Sweden)

    Somedutta Barat

    Full Text Available Invasive Salmonella infection is an important health problem that is worsening because of rising antimicrobial resistance and changing Salmonella serovar spectrum. Novel vaccines with broad serovar coverage are needed, but suitable protective antigens remain largely unknown. Here, we tested 37 broadly conserved Salmonella antigens in a mouse typhoid fever model, and identified antigen candidates that conferred partial protection against lethal disease. Antigen properties such as high in vivo abundance or immunodominance in convalescent individuals were not required for protectivity, but all promising antigen candidates were associated with the Salmonella surface. Surprisingly, this was not due to superior immunogenicity of surface antigens compared to internal antigens as had been suggested by previous studies and novel findings for CD4 T cell responses to model antigens. Confocal microscopy of infected tissues revealed that many live Salmonella resided alone in infected host macrophages with no damaged Salmonella releasing internal antigens in their vicinity. In the absence of accessible internal antigens, detection of these infected cells might require CD4 T cell recognition of Salmonella surface-associated antigens that could be processed and presented even from intact Salmonella. In conclusion, our findings might pave the way for development of an efficacious Salmonella vaccine with broad serovar coverage, and suggest a similar crucial role of surface antigens for immunity to both extracellular and intracellular pathogens.

  13. 旋毛虫成虫抗原的免疫保护性研究进展%Advances in study on protective immunity of Trichinella spiralis adult worm antigen

    Institute of Scientific and Technical Information of China (English)

    马鸣旺; 申丽洁

    2008-01-01

    The advances in study on protective immunity of Trichinella spiralis adult WOlln antigen were reviewed in this paper.Acording to the comparison of the three antigens of Trichinella spiralis,adult worm anti-gens can produce stronger protective immunity, which may serve as an important candidate of the vaccine a-gainst trichinellosis.With DNA recombination technology to clone the gene of the strong protective antigens of a-duh worm and to express them in vitro are important ways to get the vaccine against trichinellosis.%该文介绍了旋毛虫成虫抗原免疫保护性研究的进展.通过比较三期抗原的免疫保护性,表明旋毛虫成虫抗原具有较强的免疫保护作用,该抗原可能是研制旋毛虫病疫苗的重要候选抗原.利用DNA重组技术将保护性强的成虫抗原的基因克隆并在体外表达,将是获得旋毛虫病疫苗抗原的重要方法.

  14. Expression and refolding of the protective antigen of Bacillus anthracis: A model for high-throughput screening of antigenic recombinant protein refolding.

    Science.gov (United States)

    Pavan, María Elisa; Pavan, Esteban Enrique; Cairó, Fabián Martín; Pettinari, María Julia

    2016-01-01

    Bacillus anthracis protective antigen (PA) is a well known and relevant immunogenic protein that is the basis for both anthrax vaccines and diagnostic methods. Properly folded antigenic PA is necessary for these applications. In this study a high level of PA was obtained in recombinant Escherichia coli. The protein was initially accumulated in inclusion bodies, which facilitated its efficient purification by simple washing steps; however, it could not be recognized by specific antibodies. Refolding conditions were subsequently analyzed in a high-throughput manner that enabled nearly a hundred different conditions to be tested simultaneously. The recovery of the ability of PA to be recognized by antibodies was screened by dot blot using a coefficient that provided a measure of properly refolded protein levels with a high degree of discrimination. The best refolding conditions resulted in a tenfold increase in the intensity of the dot blot compared to the control. The only refolding additive that consistently yielded good results was L-arginine. The statistical analysis identified both cooperative and negative interactions between the different refolding additives. The high-throughput approach described in this study that enabled overproduction, purification and refolding of PA in a simple and straightforward manner, can be potentially useful for the rapid screening of adequate refolding conditions for other overexpressed antigenic proteins.

  15. Glycan elongation beyond the mucin associated Tn antigen protects tumor cells from immune-mediated killing

    DEFF Research Database (Denmark)

    Mathiesen, Caroline Benedicte Kjærulff; Lavrsen, Kirstine; Wandall, Hans H.;

    2013-01-01

    Membrane bound mucins are up-regulated and aberrantly glycosylated during malignant transformation in many cancer cells. This results in a negatively charged glycoprotein coat which may protect cancer cells from immune surveillance. However, only limited data have so far demonstrated the critical...... steps in glycan elongation that make aberrantly glycosylated mucins affect the interaction between cancer cells and cytotoxic effector cells of the immune system. Tn (GalNAc-Ser/Thr), STn (NeuAcα2-6GalNAc-Ser/Thr), T (Galβ1–3GalNAc-Ser/Thr), and ST (NeuAcα2-6Galβ1–3GalNAc-Ser/Thr) antigens...... only the shortest possible mucin-like glycans (Tn and STn). Glyco-engineering was performed by zinc finger nuclease (ZFN) knockout (KO) of the Core 1 enzyme chaperone COSMC, thereby preventing glycan elongation beyond the initial GalNAc residue in O-linked glycans. We find that COSMC KO in the breast...

  16. Protection of pigs against Taenia solium cysticercosis by immunization with novel recombinant antigens.

    Science.gov (United States)

    Gauci, Charles G; Jayashi, César M; Gonzalez, Armando E; Lackenby, Julia; Lightowlers, Marshall W

    2012-06-06

    Recombinant antigens from the oncosphere stage of the parasite Taenia solium were expressed in Escherichia coli. The TSOL16, TSOL45-1A and TSOL45-1B recombinant antigens, each consisting of fibronectin type III (FnIII) domain S, were produced as fusion proteins with glutathione S-transferase (GST) and maltose binding protein (MBP). Groups of pigs were immunized twice with the GST fusions of the antigens and boosted a third time with the MBP fusions prior to receiving a challenge infection with T. solium eggs. The TSOL16 antigen was found to be capable of inducing high levels of immunity in pigs against a challenge infection with T. solium. Immunological investigations identified differences in immune responses in the pigs vaccinated with the various antigens. The results demonstrate that the TSOL16 antigen could be a valuable adjunct to current porcine vaccination approaches and may allow the further development of new vaccination strategies against T. solium cysticercosis.

  17. 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.

  18. Mimotope-based vaccines of Leishmania infantum antigens and their protective efficacy against visceral leishmaniasis.

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    Lourena Emanuele Costa

    Full Text Available BACKGROUND: The development of cost-effective prophylactic strategies to prevent leishmaniasis has become a high-priority. The present study has used the phage display technology to identify new immunogens, which were evaluated as vaccines in the murine model of visceral leishmaniasis (VL. Epitope-based immunogens, represented by phage-fused peptides that mimic Leishmania infantum antigens, were selected according to their affinity to antibodies from asymptomatic and symptomatic VL dogs' sera. METHODOLOGY/MAIN FINDINGS: Twenty phage clones were selected after three selection cycles, and were evaluated by means of in vitro assays of the immune stimulation of spleen cells derived from naive and chronically infected with L. infantum BALB/c mice. Clones that were able to induce specific Th1 immune response, represented by high levels of IFN-γ and low levels of IL-4 were selected, and based on their selectivity and specificity, two clones, namely B10 and C01, were further employed in the vaccination protocols. BALB/c mice vaccinated with clones plus saponin showed both a high and specific production of IFN-γ, IL-12, and GM-CSF after in vitro stimulation with individual clones or L. infantum extracts. Additionally, these animals, when compared to control groups (saline, saponin, wild-type phage plus saponin, or non-relevant phage clone plus saponin, showed significant reductions in the parasite burden in the liver, spleen, bone marrow, and paws' draining lymph nodes. Protection was associated with an IL-12-dependent production of IFN-γ, mainly by CD8+ T cells, against parasite proteins. These animals also presented decreased parasite-mediated IL-4 and IL-10 responses, and increased levels of parasite-specific IgG2a antibodies. CONCLUSIONS/SIGNIFICANCE: This study describes two phage clones that mimic L. infantum antigens, which were directly used as immunogens in vaccines and presented Th1-type immune responses, and that significantly reduced the

  19. A naturally occurring hypoallergenic variant of vespid Antigen 5 from Polybia scutellaris venom as a candidate for allergen-specific immunotherapy.

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    Sabrina E Vinzón

    Full Text Available Stings by insects from the Hymenoptera order are known to cause life-threatening allergic reactions and impair life quality. Despite the effectiveness of conventional vespid venom immunotherapy, more standardized and safer allergy vaccines are required and recombinant hypoallergenic variants are important clinical tools. Antigen 5 is a major allergen of vespid venoms and it was previously reported that Antigen 5 from Polybia scutellaris (Poly s 5 could be a hypoallergenic variant. In this work we assess the immunological behavior and allergenic activity of Poly s 5 in order to explore its suitability for specific immunotherapy. With this aim, recombinant Poly s 5 was expressed in Pichia pastoris and the presence of cross-reactive epitopes with Pol a 5, a known allergenic Antigen 5, was investigated both at the IgG and IgE levels, by ELISA assays and a basophil-mediator release assay respectively. A molecular model was also built to better understand the relationship between immunological and structural aspects. In mice, Poly s 5 induced IgG antibodies which cross-reacted with Pol a 5. However, Poly s 5 induced only minimal amounts of IgE and was a poor inducer of basophil-mediator release, even when the cells were sensitized with Pol a 5-specific IgE. Moreover, Poly s 5-specific serum showed a specific protective activity and was able to inhibit the Pol a 5-induced basophil degranulation. Structural analysis from the molecular model revealed that a few amino acid substitutions in the N-terminal region of Poly s 5 should lead to an alteration of the surface topography and electrostatic potential of the epitopes which could be responsible for its hypoallergenic behavior. These findings, taken as a whole, show that Poly s 5 is likely a naturally occurring hypoallergenic Antigen 5 variant.

  20. A naturally occurring hypoallergenic variant of vespid Antigen 5 from Polybia scutellaris venom as a candidate for allergen-specific immunotherapy.

    Science.gov (United States)

    Vinzón, Sabrina E; Marino-Buslje, Cristina; Rivera, Elena; Biscoglio de Jiménez Bonino, Mirtha

    2012-01-01

    Stings by insects from the Hymenoptera order are known to cause life-threatening allergic reactions and impair life quality. Despite the effectiveness of conventional vespid venom immunotherapy, more standardized and safer allergy vaccines are required and recombinant hypoallergenic variants are important clinical tools. Antigen 5 is a major allergen of vespid venoms and it was previously reported that Antigen 5 from Polybia scutellaris (Poly s 5) could be a hypoallergenic variant. In this work we assess the immunological behavior and allergenic activity of Poly s 5 in order to explore its suitability for specific immunotherapy. With this aim, recombinant Poly s 5 was expressed in Pichia pastoris and the presence of cross-reactive epitopes with Pol a 5, a known allergenic Antigen 5, was investigated both at the IgG and IgE levels, by ELISA assays and a basophil-mediator release assay respectively. A molecular model was also built to better understand the relationship between immunological and structural aspects. In mice, Poly s 5 induced IgG antibodies which cross-reacted with Pol a 5. However, Poly s 5 induced only minimal amounts of IgE and was a poor inducer of basophil-mediator release, even when the cells were sensitized with Pol a 5-specific IgE. Moreover, Poly s 5-specific serum showed a specific protective activity and was able to inhibit the Pol a 5-induced basophil degranulation. Structural analysis from the molecular model revealed that a few amino acid substitutions in the N-terminal region of Poly s 5 should lead to an alteration of the surface topography and electrostatic potential of the epitopes which could be responsible for its hypoallergenic behavior. These findings, taken as a whole, show that Poly s 5 is likely a naturally occurring hypoallergenic Antigen 5 variant.

  1. Surface plasmon resonance measurements of plasma antibody avidity during primary and secondary responses to anthrax protective antigen.

    Science.gov (United States)

    Lynch, Heather E; Stewart, Shelley M; Kepler, Thomas B; Sempowski, Gregory D; Alam, S Munir

    2014-02-01

    Establishment of humoral immunity against pathogens is dependent on events that occur in the germinal center and the subsequent induction of high-affinity neutralizing antibodies. Quantitative assays that allow monitoring of affinity maturation and duration of antibody responses can provide useful information regarding the efficacy of vaccines and adjuvants. Using an anthrax protective antigen (rPA) and alum model antigen/adjuvant system, we describe a methodology for monitoring antigen-specific serum antibody concentration and avidity by surface plasmon resonance during primary and secondary immune responses. Our analyses showed that following a priming dose in mice, rPA-specific antibody concentration and avidity increases over time and reaches a maximal response in about six weeks, but gradually declines in the absence of antigenic boost. Germinal center reactions were observed early with maximal development achieved during the primary response, which coincided with peak antibody avidity responses to primary immunization. Boosting with antigen resulted in a rapid increase in rPA-specific antibody concentration and five-fold increase in avidity, which was not dependent on sustained GC development. The described methodology couples surface plasmon resonance-based plasma avidity measurements with germinal center analysis and provides a novel way to monitor humoral responses that can play a role in facilitating vaccine and adjuvant development.

  2. Variation in the cellular localization of host-protective oncospheral antigens in Taenia saginata and Taenia solium.

    Science.gov (United States)

    Jabbar, A; Verástegui, M; Lackenby, J A; Walduck, A K; Gauci, C G; Gilman, R H; Lightowlers, M W

    2010-01-01

    Immunohistochemistry and immunofluorescence with confocal microscopy were used to localize the host-protective antigens of Taenia saginata (TSA9 and TSA18) and Taenia solium (TSOL16, TSOL18 and TSOL45). In nonactivated oncospheres, TSA9 and TSOL45 antigens were found primarily in the cytoplasm of the penetration gland type one (PG1) cell. A similar pattern of staining was seen for TSOL45 in oncospheres of T. solium that remained within the oncospheral membrane. In addition, there was less intense staining of TSA9 and TSOL45 in the quadri-nucleate penetration gland type 2 (PG2) cell. TSA18, TSOL16 and TSOL18 were predominantly found in the PG2 cell. In activated oncospheres that had escaped the oncospheral membrane, the antigens (other than TSA9) were seen both in the penetration gland cell locations and throughout the oncospheral parenchyma. Co-localization analyses revealed that only TSOL16 and TSOL18 antigens were co-localized in the PG2 cell of oncospheres that had not escaped the oncospheral membrane. However, in activated oncospheres that escaped the oncospheral membrane, all three antigens of T. solium were co-localized as they were present throughout the parenchyma. No positive staining was observed on the surface of nonactivated or recently activated oncospheres of T. saginata or T. solium.

  3. 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.

  4. Acquisition of Functional Antibodies That Block the Binding of Erythrocyte-Binding Antigen 175 and Protection Against Plasmodium falciparum Malaria in Children

    Science.gov (United States)

    Irani, Vashti; Ramsland, Paul A.; Guy, Andrew J.; Siba, Peter M.; Mueller, Ivo; Richards, Jack S.; Beeson, James G.

    2015-01-01

    Background. The targets and mechanisms of human immunity to malaria are poorly understood, which poses a major barrier to malaria vaccine development. Antibodies play a key role in human immunity and may act by inhibiting receptor-binding functions of key merozoite invasion ligands. Antibodies to the major invasion ligand and vaccine candidate, erythrocyte-binding antigen 175 (EBA-175), have been linked with protection, but how these antibodies function has not been established. Methods. We developed 2 new assays that quantify the ability of antibodies to inhibit binding of EBA-175 to its erythrocyte receptor, glycophorin A, using either native or recombinant EBA-175. Binding-inhibitory antibodies were evaluated in a longitudinal cohort study of Papua New Guinean children and related to risk of malaria, age, infection status, and markers of parasite exposure. Results. Binding-inhibition assays (BIAs) were reproducible, and the 2 assays had a high level of agreement. Inhibitory antibodies were common among children, acquired in association with markers of increasing parasite exposure, and high in those children with active infection. Inhibitory antibodies correlated with total immunoglobulin G levels to the EBA-175 binding domain (region II). Importantly, binding-inhibitory antibodies were significantly associated with protection from symptomatic malaria when measured using either BIA. Conclusions. Findings suggest that naturally acquired binding-inhibitory antibodies are an important functional mechanism that contributes to protection against malaria and further supports the potential of EBA-175 as a vaccine candidate. Identifying vaccines and approaches that induce potent binding-inhibitory antibodies may be a valuable strategy in the development of highly efficacious malaria vaccines. PMID:26136391

  5. Scalable synthesis of Fmoc-protected GalNAc-threonine amino acid and T(N) antigen via nickel catalysis.

    Science.gov (United States)

    Yu, Fei; McConnell, Matthew S; Nguyen, Hien M

    2015-04-17

    The highly α-selective and scalable synthesis of the Fmoc-protected GalNAc-threonine amino acid and TN antigen in gram scale (0.5-1 g) is described. The challenging 1,2-cis-2-amino glycosidic bond is addressed through a coupling of threonine residues with C(2)-N-ortho-(trifluoromethyl)benzylidenamino trihaloacetimidate donors mediated by Ni(4-F-PhCN)4(OTf)2. The desired 1,2-cis-2-amino glycoside was obtained in 66% yield (3.77 g) with α-only selectivity and subsequently transformed into the Fmoc-protected GalNAc-threonine and TN antigen. This operationally simple procedure no longer requires utilization of the commonly used C(2)-azido donors and overcomes many of the limitations associated with the synthesis of 1,2-cis linkage.

  6. Association between Interferon Response and Protective Efficacy of NS1-Truncated Mutants as Influenza Vaccine Candidates in Chickens.

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    Hyesun Jang

    Full Text Available Influenza virus mutants that encode C-terminally truncated NS1 proteins (NS1-truncated mutants are attractive candidates for avian live attenuated influenza vaccine (LAIV development because they are both attenuated and immunogenic in chickens. We previously showed that a high protective efficacy of NS1-truncated LAIV in chickens corresponds with induction of high levels of type I interferon (IFN responses in chicken embryonic fibroblast cells. In this study, we investigated the relationship between induction of IFN and IFN-stimulated gene responses in vivo and the immunogenicity and protective efficacy of NS1-truncated LAIV. Our data demonstrates that accelerated antibody induction and protective efficacy of NS1-truncated LAIV correlates well with upregulation of IFN-stimulated genes. Further, through oral administration of recombinant chicken IFN alpha in drinking water, we provide direct evidence that type I IFN can promote rapid induction of adaptive immune responses and protective efficacy of influenza vaccine in chickens.

  7. Construction of Recombinant Baculoviruses Expressing Infectious Bursal Disease Virus Main Protective Antigen and Their Immune Effects on Chickens

    OpenAIRE

    Jingping Ge; Qi An; Shanshan Song; Dongni Gao; Wenxiang Ping

    2015-01-01

    In order to overcome the limitations of conventional vaccines for infectious bursal disease virus (IBDV), we constructed recombinant dual expression system baculoviruses with VP2 and VP2/4/3, the main protective antigens of IBDV. We compared the immune effects of the baculoviruses in avian cells and detected their control effects on chickens with infectious bursal disease. We used Western blot analysis to measure VP2 protein and VP2/4/3 polyprotein expression in avian cells infected using the...

  8. Screening of peptide libraries against protective antigen of Bacillus anthracis in a disposable microfluidic cartridge.

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    Joshua M Kogot

    Full Text Available Bacterial surface peptide display has gained popularity as a method of affinity reagent generation for a wide variety of applications ranging from drug discovery to pathogen detection. In order to isolate the bacterial clones that express peptides with high affinities to the target molecule, multiple rounds of manual magnetic activated cell sorting (MACS followed by multiple rounds of fluorescence activated cell sorting (FACS are conventionally used. Although such manual methods are effective, alternative means of library screening which improve the reproducibility, reduce the cost, reduce cross contamination, and minimize exposure to hazardous target materials are highly desired for practical application. Toward this end, we report the first semi-automated system demonstrating the potential for screening bacterially displayed peptides using disposable microfluidic cartridges. The Micro-Magnetic Separation platform (MMS is capable of screening a bacterial library containing 3 × 10¹⁰ members in 15 minutes and requires minimal operator training. Using this system, we report the isolation of twenty-four distinct peptide ligands that bind to the protective antigen (PA of Bacilus anthracis in three rounds of selection. A consensus motif WXCFTC was found using the MMS and was also found in one of the PA binders isolated by the conventional MACS/FACS approach. We compared MMS and MACS rare cell recovery over cell populations ranging from 0.1% to 0.0000001% and found that both magnetic sorting methods could recover cells down to 0.0000001% initial cell population, with the MMS having overall lower standard deviation of cell recovery. We believe the MMS system offers a compelling approach towards highly efficient, semi-automated screening of molecular libraries that is at least equal to manual magnetic sorting methods and produced, for the first time, 15-mer peptide binders to PA protein that exhibit better affinity and specificity than peptides

  9. Glycan elongation beyond the mucin associated Tn antigen protects tumor cells from immune-mediated killing.

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    Caroline B Madsen

    Full Text Available Membrane bound mucins are up-regulated and aberrantly glycosylated during malignant transformation in many cancer cells. This results in a negatively charged glycoprotein coat which may protect cancer cells from immune surveillance. However, only limited data have so far demonstrated the critical steps in glycan elongation that make aberrantly glycosylated mucins affect the interaction between cancer cells and cytotoxic effector cells of the immune system. Tn (GalNAc-Ser/Thr, STn (NeuAcα2-6GalNAc-Ser/Thr, T (Galβ1-3GalNAc-Ser/Thr, and ST (NeuAcα2-6Galβ1-3GalNAc-Ser/Thr antigens are recognized as cancer associated truncated glycans, and are expressed in many adenocarcinomas, e.g. breast- and pancreatic cancer cells. To investigate the role of the cancer associated glycan truncations in immune-mediated killing we created glyco-engineered breast- and pancreatic cancer cells expressing only the shortest possible mucin-like glycans (Tn and STn. Glyco-engineering was performed by zinc finger nuclease (ZFN knockout (KO of the Core 1 enzyme chaperone COSMC, thereby preventing glycan elongation beyond the initial GalNAc residue in O-linked glycans. We find that COSMC KO in the breast and pancreatic cancer cell lines T47D and Capan-1 increases sensitivity to both NK cell mediated antibody-dependent cellular-cytotoxicity (ADCC and cytotoxic T lymphocyte (CTL-mediated killing. In addition, we investigated the association between total cell surface expression of MUC1/MUC16 and NK or CTL mediated killing, and observed an inverse correlation between MUC16/MUC1 expression and the sensitivity to ADCC and CTL-mediated killing. Together, these data suggest that up-regulation of membrane bound mucins protects cells from immune mediated killing, and that particular glycosylation steps, as demonstrated for glycan elongation beyond Tn and STn, can be important for fine tuning of the immune escape mechanisms in cancer cells.

  10. O-antigen protects gram-negative bacteria from histone killing.

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    Catherine Chaput

    Full Text Available Beyond their traditional role of wrapping DNA, histones display antibacterial activity to Gram-negative and -positive bacteria. To identify bacterial components that allow survival to a histone challenge, we selected resistant bacteria from homologous Escherichia coli libraries that harbor plasmids carrying pieces of the chromosome in different sizes. We identified genes required for exopolysaccharide production and for the synthesis of the polysaccharide domain of the lipopolysaccharide, called O-antigen. Indeed, O-antigen and exopolysaccharide conferred further resistance to histones. Notably, O-antigen also conferred resistance to histones in the pathogens Shigella flexneri and Klebsiella pneumoniae.

  11. Oral Vaccination Against Anthrax Using a Transgenic Plant Expressing Protective Antigen.

    Science.gov (United States)

    1996-09-01

    need for effective vaccines which will induce the mucosal immunity system against this highly lethal human pathogen. Characterization of virulence factor...colonizing the mucosal tissue in the gut and therefore may induce mucosal immunity to F I antigen through association with the Peyer’s patches... mucosal immunity , the antigen must first be stable in the gut and then be able to penetrate the epithelial cells to facilitate absorption by M cells. For

  12. Priming Cross-Protective Bovine Viral Diarrhea Virus-Specific Immunity Using Live-Vectored Mosaic Antigens

    Science.gov (United States)

    Fang, Xin; Waghela, Suryakant D.; Bray, Jocelyn; Njongmeta, Leo M.; Herring, Andy; Abdelsalam, Karim W.; Chase, Christopher; Mwangi, Waithaka

    2017-01-01

    Bovine viral diarrhea virus (BVDV) plays a key role in bovine respiratory disease complex, which can lead to pneumonia, diarrhea and death of calves. Current vaccines are not very effective due, in part, to immunosuppressive traits and failure to induce broad protection. There are diverse BVDV strains and thus, current vaccines contain representative genotype 1 and 2 viruses (BVDV-1 & 2) to broaden coverage. BVDV modified live virus (MLV) vaccines are superior to killed virus vaccines, but they are susceptible to neutralization and complement-mediated destruction triggered by passively acquired antibodies, thus limiting their efficacy. We generated three novel mosaic polypeptide chimeras, designated NproE2123; NS231; and NS232, which incorporate protective determinants that are highly conserved among BVDV-1a, 1b, and BVDV-2 genotypes. In addition, strain-specific protective antigens from disparate BVDV strains were included to broaden coverage. We confirmed that adenovirus constructs expressing these antigens were strongly recognized by monoclonal antibodies, polyclonal sera, and IFN-γ-secreting T cells generated against diverse BVDV strains. In a proof-of-concept efficacy study, the multi-antigen proto-type vaccine induced higher, but not significantly different, IFN-γ spot forming cells and T-cell proliferation compared to a commercial MLV vaccine. In regards to the humoral response, the prototype vaccine induced higher BVDV-1 specific neutralizing antibody titers, whereas the MLV vaccine induced higher BVDV-2 specific neutralizing antibody titers. Following BVDV type 2a (1373) challenge, calves immunized with the proto-type or the MLV vaccine had lower clinical scores compared to naïve controls. These results support the hypothesis that a broadly protective subunit vaccine can be generated using mosaic polypeptides that incorporate rationally selected and validated protective determinants from diverse BVDV strains. Furthermore, regarding biosafety of using a

  13. A booster vaccine expressing a latency-associated antigen augments BCG induced immunity and confers enhanced protection against tuberculosis.

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    Bappaditya Dey

    Full Text Available BACKGROUND: In spite of a consistent protection against tuberculosis (TB in children, Mycobacterium bovis Bacille Calmette-Guerin (BCG fails to provide adequate protection against the disease in adults as well as against reactivation of latent infections or exogenous reinfections. It has been speculated that failure to generate adequate memory T cell response, elicitation of inadequate immune response against latency-associated antigens and inability to impart long-term immunity against M. tuberculosis infections are some of the key factors responsible for the limited efficiency of BCG in controlling TB. METHODS/PRINCIPAL FINDINGS: In this study, we evaluated the ability of a DNA vaccine expressing α-crystallin--a key latency antigen of M. tuberculosis to boost the BCG induced immunity. 'BCG prime-DNA boost' regimen (B/D confers robust protection in guinea pigs along with a reduced pathology in comparison to BCG vaccination (1.37 log(10 and 1.96 log(10 fewer bacilli in lungs and spleen, respectively; p<0.01. In addition, B/D regimen also confers enhanced protection in mice. Further, we show that B/D immunization in mice results in a heightened frequency of PPD and antigen specific multi-functional CD4 T cells (3(+ simultaneously producing interferon (IFNγ, tumor necrosis factor (TNFα and interleukin (IL2. CONCLUSIONS/SIGNIFICANCE: These results clearly indicate the superiority of α-crystallin based B/D regimen over BCG. Our study, also demonstrates that protection against TB is predictable by an increased frequency of 3(+ Th1 cells with superior effector functions. We anticipate that this study would significantly contribute towards the development of superior booster vaccines for BCG vaccinated individuals. In addition, this regimen can also be expected to reduce the risk of developing active TB due to reactivation of latent infection.

  14. Enhanced protective efficacy of nonpathogenic recombinant leishmania tarentolae expressing cysteine proteinases combined with a sand fly salivary antigen.

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    Farnaz Zahedifard

    2014-03-01

    Full Text Available BACKGROUND: Novel vaccination approaches are needed to prevent leishmaniasis. Live attenuated vaccines are the gold standard for protection against intracellular pathogens such as Leishmania and there have been new developments in this field. The nonpathogenic to humans lizard protozoan parasite, Leishmania (L tarentolae, has been used effectively as a vaccine platform against visceral leishmaniasis in experimental animal models. Correspondingly, pre-exposure to sand fly saliva or immunization with a salivary protein has been shown to protect mice against cutaneous leishmaniasis. METHODOLOGY/PRINCIPAL FINDINGS: Here, we tested the efficacy of a novel combination of established protective parasite antigens expressed by L. tarentolae together with a sand fly salivary antigen as a vaccine strategy against L. major infection. The immunogenicity and protective efficacy of different DNA/Live and Live/Live prime-boost vaccination modalities with live recombinant L. tarentolae stably expressing cysteine proteinases (type I and II, CPA/CPB and PpSP15, an immunogenic salivary protein from Phlebotomus papatasi, a natural vector of L. major, were tested both in susceptible BALB/c and resistant C57BL/6 mice. Both humoral and cellular immune responses were assessed before challenge and at 3 and 10 weeks after Leishmania infection. In both strains of mice, the strongest protective effect was observed when priming with PpSP15 DNA and boosting with PpSP15 DNA and live recombinant L. tarentolae stably expressing cysteine proteinase genes. CONCLUSION/SIGNIFICANCE: The present study is the first to use a combination of recombinant L. tarentolae with a sand fly salivary antigen (PpSP15 and represents a novel promising vaccination approach against leishmaniasis.

  15. Enhanced Protective Efficacy of Nonpathogenic Recombinant Leishmania tarentolae Expressing Cysteine Proteinases Combined with a Sand Fly Salivary Antigen

    Science.gov (United States)

    Taheri, Tahereh; Taslimi, Yasaman; Doustdari, Fatemeh; Seyed, Negar; Torkashvand, Fatemeh; Meneses, Claudio; Papadopoulou, Barbara; Kamhawi, Shaden; Valenzuela, Jesus G.; Rafati, Sima

    2014-01-01

    Background Novel vaccination approaches are needed to prevent leishmaniasis. Live attenuated vaccines are the gold standard for protection against intracellular pathogens such as Leishmania and there have been new developments in this field. The nonpathogenic to humans lizard protozoan parasite, Leishmania (L) tarentolae, has been used effectively as a vaccine platform against visceral leishmaniasis in experimental animal models. Correspondingly, pre-exposure to sand fly saliva or immunization with a salivary protein has been shown to protect mice against cutaneous leishmaniasis. Methodology/Principal Findings Here, we tested the efficacy of a novel combination of established protective parasite antigens expressed by L. tarentolae together with a sand fly salivary antigen as a vaccine strategy against L. major infection. The immunogenicity and protective efficacy of different DNA/Live and Live/Live prime-boost vaccination modalities with live recombinant L. tarentolae stably expressing cysteine proteinases (type I and II, CPA/CPB) and PpSP15, an immunogenic salivary protein from Phlebotomus papatasi, a natural vector of L. major, were tested both in susceptible BALB/c and resistant C57BL/6 mice. Both humoral and cellular immune responses were assessed before challenge and at 3 and 10 weeks after Leishmania infection. In both strains of mice, the strongest protective effect was observed when priming with PpSP15 DNA and boosting with PpSP15 DNA and live recombinant L. tarentolae stably expressing cysteine proteinase genes. Conclusion/Significance The present study is the first to use a combination of recombinant L. tarentolae with a sand fly salivary antigen (PpSP15) and represents a novel promising vaccination approach against leishmaniasis. PMID:24675711

  16. Cloning and Expression of Fusion Genes of Domain A-1 Protective Antigen of Bacillus Anthracis and Shigella Enterotoxin B Subunit (Stxb In E. Coil

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    AH ahmadi

    2015-02-01

    Conclusion: The findings of the current study revealed that this antigen can be raised as an anti-cancer and recombinant vaccine candidate against types of Shigella, Escherichia coli and Bacillus anthracis which can be due to such factors as identification of antigen(PA by antibody PA20, its apoptosis induction properties, property of immunogenicity, adjuvant and delivery of STxB protein and high expression levels of Gb3 in human cancer cells.

  17. Vaccination with TAT-antigen fusion protein induces protective, CD8(+) T cell-mediated immunity against Leishmania major.

    Science.gov (United States)

    Kronenberg, Katharina; Brosch, Sven; Butsch, Florian; Tada, Yayoi; Shibagaki, Naotaka; Udey, Mark C; von Stebut, Esther

    2010-11-01

    In murine leishmaniasis, healing is mediated by IFN-γ-producing CD4(+) and CD8(+) T cells. Thus, an efficacious vaccine should induce Th1 and Tc1 cells. Dendritic cells (DCs) pulsed with exogenous proteins primarily induce strong CD4-dependent immunity; induction of CD8 responses has proven to be difficult. We evaluated the immunogenicity of fusion proteins comprising the protein transduction domain of HIV-1 TAT and the Leishmania antigen LACK (Leishmania homolog of receptors for activated C kinase), as TAT-fusion proteins facilitate major histocompatibility complex class I-dependent antigen presentation. In vitro, TAT-LACK-pulsed DCs induced stronger proliferation of Leishmania-specific CD8(+) T cells compared with DCs incubated with LACK alone. Vaccination with TAT-LACK-pulsed DCs or fusion proteins plus adjuvant in vivo significantly improved disease outcome in Leishmania major-infected mice and was superior to vaccination with DCs treated with LACK alone. Vaccination with DC+TAT-LACK resulted in stronger proliferation of CD8(+) T cells when compared with immunization with DC+LACK. Upon depletion of CD4(+) or CD8(+) T cells, TAT-LACK-mediated protection was lost. TAT-LACK-pulsed IL-12p40-deficient DCs did not promote protection in vivo. In summary, these data show that TAT-fusion proteins are superior in activating Leishmania-specific Tc1 cells when compared with antigen alone and suggest that IL-12-dependent preferential induction of antigen-specific CD8(+) cells promotes significant protection against this important human pathogen.

  18. [Blood groups - minuses and pluses. Do the blood group antigens protect us from infectious diseases?].

    Science.gov (United States)

    Czerwiński, Marcin

    2015-06-25

    Human blood can be divided into groups, which is a method of blood classification based on the presence or absence of inherited erythrocyte surface antigens that can elicit immune response. According to the International Society of Blood Transfusion, there are 341 blood group antigens collected in 35 blood group systems. These antigens can be proteins, glycoproteins or glycosphingolipids, and function as transmembrane transporters, ion channels, adhesion molecules or receptors for other proteins. The majority of blood group antigens is present also on another types of cells. Due to their localization on the surface of cells, blood group antigens can act as receptors for various pathogens or their toxins, such as protozoa (malaria parasites), bacteria (Helicobacter pylori, Vibrio cholerae and Shigella dysenteriae) and viruses (Noroviruses, Parvoviruses, HIV). If the presence of group antigen (or its variant which arised due to mutation) is beneficial for the host (e.g. because pathogens are not able to bind to the cells), the blood group may become a selection trait, leading to its dissemination in the population exposed to that pathogen. There are thirteen blood group systems that can be related to pathogen resistance, and it seems that the particular influence was elicit by malaria parasites. It is generally thought that the high incidence of blood groups such as O in the Amazon region, Fy(a-b-) in Africa and Ge(-) in Papua-New Guinea is the result of selective pressure from malaria parasite. This review summarizes the data about relationship between blood groups and resistance to pathogens.

  19. Immune responses and protective efficacy induced by 85B antigen and early secreted antigenic target-6 kDa antigen fusion protein secreted by recombinant bacille Calmette-Guérin.

    Science.gov (United States)

    Shi, Changhong; Wang, Xiaowu; Zhang, Hai; Xu, Zhikai; Li, Yuan; Yuan, Lintian

    2007-04-01

    In an attempt to improve immune responses and protective efficacy, we constructed two recombinant bacille Calmette-Guérin (rBCG) strains expressing an 85B antigen (Ag85B) and early secreted antigenic target-6 kDa antigen (ESAT6) of Mycobacterium tuberculosis (MTB) fusion protein. Both rBCG strains have the same protein insertion but in a different order (Ag85B-ESAT6 and ESAT6-Ag85B). The cultured supernatant of rBCG strains and the sera from the mice immunized with the fusion protein Ag85B-ESAT6 or ESAT6-Ag85B formed a band with a fraction size of 37 kDa, equalivalent to the sum of Ag85B and ESAT6. Six weeks after BALB/c mice were immunized with BCG or rBCG, spleen lymphocytes showed significant proliferation in response to culture filtrate protein of MTB. Compared with the BCG group, mice vaccinated with rBCG elicited a high level increase of immunoglobulin G antibodies to culture filtrate protein in the serum. The gamma-interferon levels in the lymphocyte culture medium supernatants increased remarkably in the rBCG1 group, significantly higher than that of the BCG immunized group (p0.05).

  20. Naturally acquired antibodies to Bacillus anthracis protective antigen in vultures of southern Africa

    Directory of Open Access Journals (Sweden)

    P. C.B. Turnbull

    2008-08-01

    Full Text Available TURNBULLP, P.C.B. DIEKMANNM,M., KILIAN, J.W., VERSFELDW, W.,DE VOS, V., ARNTZENL, L.,WOLTER, K., BARTELS, P. & KOTZE, A. 2008.N aturally acquired antibodies to Bacillusa nthracisp rotective antigeni n vultureso f southern Africa. Onderstepoort Journal of Veterinary Research, T5:95-102 Sera from 19 wild caught vultures in northern Namibia and 15 (12 wild caught and three captive bred but with minimal histories in North West Province, South Africa, were examined by an enzyme-linked immunosorbenats say( ELISAf or antibodiesto the Bacillus anthracis toxin protective antigen (PA. As assessed from the baseline established with a control group of ten captive reared vultures with well-documented histories, elevated titres were found in 12 of the 19 (63% wild caught Namibian birds as compared with none of the 15 South African ones. There was a highly significant difference between the Namibian group as a hole and the other groups (P < 0.001 and no significant difference between the South African and control groups (P > 0.05. Numbers in the Namibian group were too small to determine any significances in species-, sex- or age-related differences within the raw data showing elevated titres in four out of six Cape Vultures, Gyps coprotheress, six out of ten Whitebacked Vultures, Gyps africanus, and one out of three Lappet-faced Vultures, Aegypiust racheliotus, or in five of six males versus three of seven females, and ten of 15 adults versus one of four juveniles. The results are in line with the available data on the incidence of anthrax in northern Namibia and South Africa and the likely contact of the vultures tested with anthrax carcasses. lt is not known whether elevated titre indicates infection per se in vultures or absorption of incompletely digested epitopes of the toxin or both. The results are discussed in relation to distances travelled by vultures as determined by new tracking techniques, how serology can reveal anthrax activity in an area and

  1. Gamma irradiated antigen extracts improves the immune response and protection in experimental toxoplasmosis

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Andrea da; Galisteo Junior, Andres Jimenez; Andrade Junior, Heitor Franco de, E-mail: andreacosta@usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Medicina Tropical; Zorgi, Nahiara Estevez [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Ciencias Biomedicas; Nascimento, Nanci do [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    We aimed to use ionizing radiation on soluble extracts of T. gondii tachyzoites (AgTg) and tested the ability of these extracts to induce immunity in BALB/c mice against a challenge. T. gondii RH strain AgTg was irradiated with Co-60 at 0.25 to 4 kGy and were affected after 1 kGy, as evidenced by a progressive high molecular weight protein aggregates and no loss in antigenicity, as detected by immunoblotting, except after 4kGy. BALB/c mice were immunized with biweekly doses of 03 s.c. native or irradiated AgTg without adjuvants; the anti-T.gondii IgG production was detected by ELISA, and higher levels and avidity were detected in mice immunized with 1.5 kGy AgTg compared to controls (p<0.05). Mice immunized with native AgTg exhibited spleen CD19{sup +} B, CD3{sup +}CD4{sup +} or CD3{sup +}CD8{sup +} T cell proliferation levels of 5%, while 1.5 kGy-immunized mice exhibited spleen cell proliferation levels of 12.2%, primarily for CD19{sup +} or CD3{sup +}CD8{sup +} lymphocytes and less evidently for CD3{sup +}CD4{sup +} (8.8%) helper T lymphocytes. All cells from control mice showed little to no proliferation when stimulated with AgTg. These cells secreted more IFN-γ in the 1.5 kGy AgTg-immunized group (p<0.05). BALB/c mice immunized with 1.5 kGy and challenged with different strains of T. gondii were partially protected, as evidenced by survival after RH virulent strain challenge (p<0.0001) but also after ME-49 strain challenge: the brain cyst numbers (p<0.05) and the levels of T. gondii DNA measured by real-time PCR (p<0.05) decreased compared to non-immunized controls. (author)

  2. Protection of Mice with a Divalent Tuberculosis DNA Vaccine Encoding Antigens Ag85B and MPT64

    Institute of Scientific and Technical Information of China (English)

    Xia TIAN; Hong CAI; Yu-Xian ZHU

    2004-01-01

    DNA vaccine may be a promising tool for controlling tuberculosis development. However,vaccines encoding single antigens of mycobacterium did not produce protective effect as BCG did. In the present study, we evaluated the immunogenicity and protective efficacy of a divalent DNA vaccine encoding two immunodominant antigens Ag85B and MPT64 of Mycobacterium tuberculosis. We found that both humoral and Th1-type (high IFN-γ, low IL-4) cellular responses obtained from the divalent DNA vaccine group were significantly higher than that conferred by BCG. RT-PCR results showed that antigens were expressed differentially in various organs in divalent DNA vaccine group. The survival rate for mice treated with the divalent DNA vaccine after challenging with high doses of virulent M. tuberculosis H37Rv was significantly higher than that of the BCG group or any of the single DNA vaccine group. Significant differences were also found between the single and divalent DNA vaccinated mice in terms of body, spleen and lung weight. Bacterial loading decreased about 2000-fold in lungs and about 100-fold in spleens of divalent DNA vaccinated mice when compared with that of the control group. We conclude that our divalent DNA vaccine may be a better choice for controlling tuberculosis disease in animals.

  3. Immune Responses and Protective Efficacy Induced by 85B Antigen and Early Secreted Antigenic Target-6 kDa Antigen Fusion Protein Secreted by Recombinant Bacille Calmette-Guérin

    Institute of Scientific and Technical Information of China (English)

    Changhong SHI; Xiaowu WANG; Hai ZHANG; Zhikai XU; Yuan LI; Lintian YUAN

    2007-01-01

    In an attempt to improve immune responses and protective efficacy, we constructed two recombinant bacille Calmette-Guérin (rBCG) strains expressing an 85B antigen (Ag85B) and early secreted antigenic target-6 kDa antigen (ESAT6) of Mycobacterium tuberculosis (MTB) fusion protein. Both rBCG strains have the same protein insertion but in a different order (Ag85B-ESAT6 and ESAT6-Ag85B). The cultured supernatant of rBCG strains and the sera from the mice immunized with the fusion protein Ag85B-ESAT6 or ESAT6-Ag85B formed a band with a fraction size of 37 kDa, equalivalent to the sum of Ag85B and ESAT6. Six weeks after BALB/c mice were immunized with BCG or rBCG, spleen lymphocytes showed significant proliferation in response to culture filtrate protein of MTB. Compared with the BCG group, mice vaccinated with rBCG elicited a high level increase of immunoglobulin G antibodies to culture filtrate protein in the serum. The γ-interferon levels in the lymphocyte culture medium supernatants increased remarkably in the rBCG1 group, significantly higher than that of the BCG immunized group (P<0.05). Four weeks after vaccination, mice were infected with M. tuberculosis H37Rv and a dramatic reduction in the numbers of MTB colony forming units in the spleens and lungs was observed in the two rBCG immunization groups.Although these rBCG strains were more immunogenic, their protective effect was comparable to the classical BCG strain, and there were no significant differences between two rBCG groups (P>0.05).

  4. Oxidized multiwalled carbon nanotubes as antigen delivery system to promote superior CD8(+) T cell response and protection against cancer.

    Science.gov (United States)

    de Faria, Paula Cristina Batista; dos Santos, Luara Isabela; Coelho, João Paulo; Ribeiro, Henrique Bücker; Pimenta, Marcos Assunção; Ladeira, Luiz Orlando; Gomes, Dawidson Assis; Furtado, Clascídia Aparecida; Gazzinelli, Ricardo Tostes

    2014-09-10

    Properties like high interfacial area with cellular membranes, unique ability to incorporate multiple functionalization, as well as compatibility and transport in biological fluids make carbon nanotubes (CNTs) useful for a variety of therapeutic and drug-delivery applications. Here we used a totally synthetic hybrid supramolecule as an anticancer vaccine formulation. This complex structure comprises CNTs as delivery system for the Cancer Testis Antigen named NY-ESO-1, allied to a synthetic Toll-Like Receptor agonist. The CNT constructs were rapidly internalized into dendritic cells, both in vitro and in vivo, and served as an intracellular antigen depot. This property favored the induction of strong CD4(+) T as well as CD8(+) T cell-mediated immune responses against the NY-ESO-1. Importantly, the vaccination significantly delayed the tumor development and prolonged the mice survival, highlighting the potential application of CNTs as a vaccine delivery system to provide superior immunogenicity and strong protection against cancer.

  5. Evaluation of eight live attenuated vaccine candidates for protection against challenge with virulent Mycobacterium avium subspecies paratuberculosis in mice.

    Science.gov (United States)

    Bannantine, John P; Everman, Jamie L; Rose, Sasha J; Babrak, Lmar; Katani, Robab; Barletta, Raúl G; Talaat, Adel M; Gröhn, Yrjö T; Chang, Yung-Fu; Kapur, Vivek; Bermudez, Luiz E

    2014-01-01

    Johne's disease is caused by Mycobacterium avium subsp. paratuberculosis (MAP), which results in serious economic losses worldwide in farmed livestock such as cattle, sheep, and goats. To control this disease, an effective vaccine with minimal adverse effects is needed. In order to identify a live vaccine for Johne's disease, we evaluated eight attenuated mutant strains of MAP using a C57BL/6 mouse model. The persistence of the vaccine candidates was measured at 6, 12, and 18 weeks post vaccination. Only strains 320, 321, and 329 colonized both the liver and spleens up until the 12-week time point. The remaining five mutants showed no survival in those tissues, indicating their complete attenuation in the mouse model. The candidate vaccine strains demonstrated different levels of protection based on colonization of the challenge strain in liver and spleen tissues at 12 and 18 weeks post vaccination. Based on total MAP burden in both tissues at both time points, strain 315 (MAP1566::Tn5370) was the most protective whereas strain 318 (intergenic Tn5367 insertion between MAP0282c and MAP0283c) had the most colonization. Mice vaccinated with an undiluted commercial vaccine preparation displayed the highest bacterial burden as well as enlarged spleens indicative of a strong infection. Selected vaccine strains that showed promise in the mouse model were moved forward into a goat challenge model. The results suggest that the mouse trial, as conducted, may have a relatively poor predictive value for protection in a ruminant host such as goats.

  6. Adoptive transfer of helminth antigen-pulsed dendritic cells protects against the development of experimental colitis in mice.

    Science.gov (United States)

    Matisz, Chelsea E; Leung, Gabriella; Reyes, Jose Luis; Wang, Arthur; Sharkey, Keith A; McKay, Derek M

    2015-11-01

    Infection with helminth parasites and treatment with worm extracts can suppress inflammatory disease, including colitis. Postulating that dendritic cells (DCs) participated in the suppression of inflammation and seeking to move beyond the use of helminths per se, we tested the ability of Hymenolepis diminuta antigen-pulsed DCs to suppress colitis as a novel cell-based immunotherapy. Bone marrow derived DCs pulsed with H. diminuta antigen (HD-DCs), or PBS-, BSA-, or LPS-DCs as controls, were transferred into wild-type (WT), interleukin-10 (IL-10) knock-out (KO), and RAG-1 KO mice, and the impact on dinitrobenzene sulphonic acid (DNBS)-induced colitis and splenic cytokine production assessed 72 h later. Mice receiving HD-DCs were significantly protected from DNBS-induced colitis and of the experimental groups only these mice displayed increased Th2 cytokines and IL-10 production. Adoptive transfer of HD-DCs protected neither RAG-1 nor IL-10 KO mice from DNBS-colitis. Furthermore, the transfer of CD4(+) splenocytes from recipients of HD-DCs protected naïve mice against DNBS-colitis, in an IL-10 dependent manner. Thus, HD-DCs are a novel anti-colitic immunotherapy that can educate anti-colitic CD4(+) T cells: mechanistically, the anti-colitic effect of HD-DCs requires that the host has an adaptive immune response and the ability to mobilize IL-10.

  7. The role of Plasmodium falciparum variant surface antigens in protective immunity and vaccine development

    DEFF Research Database (Denmark)

    Hviid, Lars

    2010-01-01

    There is substantial immuno-epidemiological evidence that the parasite-encoded, so-called variant surface antigens (VSAs), such as PfEMP1 on the surface of infected erythrocytes (IEs) are important-in some cases probably decisive determinants of clinical outcome of P. falciparum malaria. The evid...

  8. Immunization with a Recombinant, Pseudomonas fluorescens-Expressed, Mutant Form of Bacillus anthracis-Derived Protective Antigen Protects Rabbits from Anthrax Infection.

    Directory of Open Access Journals (Sweden)

    Matthew D Reed

    Full Text Available Protective antigen (PA, one of the components of the anthrax toxin, is the major component of human anthrax vaccine (Biothrax. Human anthrax vaccines approved in the United States and Europe consist of an alum-adsorbed or precipitated (respectively supernatant material derived from cultures of toxigenic, non-encapsulated strains of Bacillus anthracis. Approved vaccination schedules in humans with either of these vaccines requires several booster shots and occasionally causes adverse injection site reactions. Mutant derivatives of the protective antigen that will not form the anthrax toxins have been described. We have cloned and expressed both mutant (PA SNKE167-ΔFF-315-E308D and native PA molecules recombinantly and purified them. In this study, both the mutant and native PA molecules, formulated with alum (Alhydrogel, elicited high titers of anthrax toxin neutralizing anti-PA antibodies in New Zealand White rabbits. Both mutant and native PA vaccine preparations protected rabbits from lethal, aerosolized, B. anthracis spore challenge subsequent to two immunizations at doses of less than 1 μg.

  9. Immunization with a Recombinant, Pseudomonas fluorescens-Expressed, Mutant Form of Bacillus anthracis-Derived Protective Antigen Protects Rabbits from Anthrax Infection.

    Science.gov (United States)

    Reed, Matthew D; Wilder, Julie A; Mega, William M; Hutt, Julie A; Kuehl, Philip J; Valderas, Michelle W; Chew, Lawrence L; Liang, Bertrand C; Squires, Charles H

    2015-01-01

    Protective antigen (PA), one of the components of the anthrax toxin, is the major component of human anthrax vaccine (Biothrax). Human anthrax vaccines approved in the United States and Europe consist of an alum-adsorbed or precipitated (respectively) supernatant material derived from cultures of toxigenic, non-encapsulated strains of Bacillus anthracis. Approved vaccination schedules in humans with either of these vaccines requires several booster shots and occasionally causes adverse injection site reactions. Mutant derivatives of the protective antigen that will not form the anthrax toxins have been described. We have cloned and expressed both mutant (PA SNKE167-ΔFF-315-E308D) and native PA molecules recombinantly and purified them. In this study, both the mutant and native PA molecules, formulated with alum (Alhydrogel), elicited high titers of anthrax toxin neutralizing anti-PA antibodies in New Zealand White rabbits. Both mutant and native PA vaccine preparations protected rabbits from lethal, aerosolized, B. anthracis spore challenge subsequent to two immunizations at doses of less than 1 μg.

  10. Cooperation between CD4+ T Cells and Humoral Immunity Is Critical for Protection against Dengue Using a DNA Vaccine Based on the NS1 Antigen.

    Directory of Open Access Journals (Sweden)

    Antônio J S Gonçalves

    2015-12-01

    Full Text Available Dengue virus (DENV is spread through most tropical and subtropical areas of the world and represents a serious public health problem. At present, the control of dengue disease is mainly hampered by the absence of antivirals or a vaccine, which results in an estimated half worldwide population at risk of infection. The immune response against DENV is not yet fully understood and a better knowledge of it is now recognized as one of the main challenge for vaccine development. In previous studies, we reported that a DNA vaccine containing the signal peptide sequence from the human tissue plasminogen activator (t-PA fused to the DENV2 NS1 gene (pcTPANS1 induced protection against dengue in mice. In the present work, we aimed to elucidate the contribution of cellular and humoral responses elicited by this vaccine candidate for protective immunity. We observed that pcTPANS1 exerts a robust protection against dengue, inducing considerable levels of anti-NS1 antibodies and T cell responses. Passive immunization with anti-NS1 antibodies conferred partial protection in mice infected with low virus load (4 LD50, which was abrogated with the increase of viral dose (40 LD50. The pcTPANS1 also induced activation of CD4+ and CD8+ T cells. We detected production of IFN-γ and a cytotoxic activity by CD8+ T lymphocytes induced by this vaccine, although its contribution in the protection was not so evident when compared to CD4+ cells. Depletion of CD4+ cells in immunized mice completely abolished protection. Furthermore, transfer experiments revealed that animals receiving CD4+ T cells combined with anti-NS1 antiserum, both obtained from vaccinated mice, survived virus infection with survival rates not significantly different from pcTPANS1-immunized animals. Taken together, results showed that the protective immune response induced by the expression of NS1 antigen mediated by the pcTPANS1 requires a cooperation between CD4+ T cells and the humoral immunity.

  11. Cooperation between CD4+ T Cells and Humoral Immunity Is Critical for Protection against Dengue Using a DNA Vaccine Based on the NS1 Antigen.

    Science.gov (United States)

    Gonçalves, Antônio J S; Oliveira, Edson R A; Costa, Simone M; Paes, Marciano V; Silva, Juliana F A; Azevedo, Adriana S; Mantuano-Barradas, Marcio; Nogueira, Ana Cristina M A; Almeida, Cecília J; Alves, Ada M B

    2015-12-01

    Dengue virus (DENV) is spread through most tropical and subtropical areas of the world and represents a serious public health problem. At present, the control of dengue disease is mainly hampered by the absence of antivirals or a vaccine, which results in an estimated half worldwide population at risk of infection. The immune response against DENV is not yet fully understood and a better knowledge of it is now recognized as one of the main challenge for vaccine development. In previous studies, we reported that a DNA vaccine containing the signal peptide sequence from the human tissue plasminogen activator (t-PA) fused to the DENV2 NS1 gene (pcTPANS1) induced protection against dengue in mice. In the present work, we aimed to elucidate the contribution of cellular and humoral responses elicited by this vaccine candidate for protective immunity. We observed that pcTPANS1 exerts a robust protection against dengue, inducing considerable levels of anti-NS1 antibodies and T cell responses. Passive immunization with anti-NS1 antibodies conferred partial protection in mice infected with low virus load (4 LD50), which was abrogated with the increase of viral dose (40 LD50). The pcTPANS1 also induced activation of CD4+ and CD8+ T cells. We detected production of IFN-γ and a cytotoxic activity by CD8+ T lymphocytes induced by this vaccine, although its contribution in the protection was not so evident when compared to CD4+ cells. Depletion of CD4+ cells in immunized mice completely abolished protection. Furthermore, transfer experiments revealed that animals receiving CD4+ T cells combined with anti-NS1 antiserum, both obtained from vaccinated mice, survived virus infection with survival rates not significantly different from pcTPANS1-immunized animals. Taken together, results showed that the protective immune response induced by the expression of NS1 antigen mediated by the pcTPANS1 requires a cooperation between CD4+ T cells and the humoral immunity.

  12. Yersinia pestis with regulated delayed attenuation as a vaccine candidate to induce protective immunity against plague.

    Science.gov (United States)

    Sun, Wei; Roland, Kenneth L; Kuang, Xiaoying; Branger, Christine G; Curtiss, Roy

    2010-03-01

    Two mutant strains of Yersinia pestis KIM5+, a Deltacrp mutant and a mutant with arabinose-dependent regulated delayed-shutoff crp expression (araC P(BAD) crp), were constructed, characterized in vitro, and evaluated for virulence, immunogenicity, and protective efficacy in mice. Both strains were highly attenuated by the subcutaneous (s.c.) route. The 50% lethal doses (LD(50)s) of the Deltacrp and araC P(BAD) crp mutants were approximately 1,000,000-fold and 10,000-fold higher than those of Y. pestis KIM5+, respectively, indicating that both strains were highly attenuated. Mice vaccinated s.c. with 3.8 x 10(7) CFU of the Deltacrp mutant developed high anti-Y. pestis and anti-LcrV serum IgG titers, both with a strong Th2 bias, and induced protective immunity against subcutaneous challenge with virulent Y. pestis (80% survival) but no protection against pulmonary challenge. Mice vaccinated with 3.0 x 10(4) CFU of the araC P(BAD) crp mutant also developed high anti-Y. pestis and anti-LcrV serum IgG titers but with a more balanced Th1/Th2 response. This strain induced complete protection against s.c. challenge and partial protection (70% survival) against pulmonary challenge. Our results demonstrate that arabinose-dependent regulated crp expression is an effective strategy to attenuate Y. pestis while retaining strong immunogenicity, leading to protection against the pneumonic and bubonic forms of plague.

  13. Bo-lysin: A Potential Candidate as a biomarker of Protection after Vaccination against Tuberculosis

    Science.gov (United States)

    Tuberculosis (TB) is still a major health problem worldwide. A Th1 type response with release of IFN {gamma}https://webmail.utmb.edu/math/gamma.gif and cytotoxic granules such as granulysin and perforin, play a major role in the disease. Measurements of protection after TB vaccination include IFN {...

  14. Adaptable Holders for Arc-Jet Screening Candidate Thermal Protection System Repair Materials

    Science.gov (United States)

    Riccio, Joe; Milhoan, Jim D.

    2010-01-01

    Reusable holders have been devised for evaluating high-temperature, plasma-resistant re-entry materials, especially fabrics. Typical material samples tested support thermal-protection-system damage repair requiring evaluation prior to re-entry into terrestrial atmosphere. These tests allow evaluation of each material to withstand the most severe predicted re-entry conditions.

  15. IgG2 antibodies against a clinical grade Plasmodium falciparum CSP vaccine antigen associate with protection against transgenic sporozoite challenge in mice.

    Directory of Open Access Journals (Sweden)

    Robert Schwenk

    Full Text Available The availability of a highly purified and well characterized circumsporozoite protein (CSP is essential to improve upon the partial success of recombinant CSP-based malaria vaccine candidates. Soluble, near full-length, Plasmodium falciparum CSP vaccine antigen (CS/D was produced in E. coli under bio-production conditions that comply with current Good Manufacturing Practices (cGMP. A mouse immunogenicity study was conducted using a stable oil-in-water emulsion (SE of CS/D in combination with the Toll-Like Receptor 4 (TLR4 agonist Glucopyranosyl Lipid A (GLA/SE, or one of two TLR7/8 agonists: R848 (un-conjugated or 3M-051 (covalently conjugated. Compared to Alum and SE, GLA/SE induced higher CS/D specific antibody response in Balb/c mice. Subclass analysis showed higher IgG2:IgG1 ratio of GLA/SE induced antibodies as compared to Alum and SE. TLR synergy was not observed when soluble R848 was mixed with GLA/SE. Antibody response of 3M051 formulations in Balb/c was similar to GLA/SE, except for the higher IgG2:IgG1 ratio and a trend towards higher T cell responses in 3M051 containing groups. However, no synergistic enhancement of antibody and T cell response was evident when 3M051 conjugate was mixed with GLA/SE. In C57Bl/6 mice, CS/D adjuvanted with 3M051/SE or GLA/SE induced higher CSP repeat specific titers compared to SE. While, 3M051 induced antibodies had high IgG2c:IgG1 ratio, GLA/SE promoted high levels of both IgG1 and IgG2c. GLA/SE also induced more potent T-cell responses compared to SE in two independent C57/BL6 vaccination studies, suggesting a balanced and productive T(H1/T(H2 response. GLA and 3M-051 similarly enhanced the protective efficacy of CS/D against challenge with a transgenic P. berghei parasite and most importantly, high levels of cytophilic IgG2 antibodies were associated with protection in this model. Our data indicated that the cGMP-grade, soluble CS/D antigen combined with the TLR4-containing adjuvant GLA/SE warrants

  16. Identification of protective pneumococcal T(H17 antigens from the soluble fraction of a killed whole cell vaccine.

    Directory of Open Access Journals (Sweden)

    Kristin L Moffitt

    Full Text Available Mucosal or parenteral immunization with a killed unencapsulated pneumococcal whole cell antigen (WCA with an adjuvant protects mice from colonization by a T(H17 CD4+ cell-mediated mechanism. Using preparative SDS gels, we separated the soluble proteins that compose the WCA in order to identify fractions that were immunogenic and protective. We screened these fractions for their ability to stimulate IL-17A secretion from splenocytes obtained from mice immunized with WCA and adjuvant. We identified 12 proteins within the stimulatory fractions by mass spectrometry; these proteins were then cloned, recombinantly expressed and purified using an Escherichia coli expression system. The ability of these proteins to induce IL-17A secretion was then evaluated by stimulation of mouse splenocytes. Of the four most stimulatory proteins, three were protective in a mouse pneumococcal serotype 6B colonization model. This work thus describes a method for identifying immunogenic proteins from the soluble fraction of pneumococcus and shows that several of the proteins identified protect mice from colonization when used as mucosal vaccines. We propose that, by providing protection against pneumococcal colonization, one or more of these proteins may serve as components of a multivalent pneumococcal vaccine.

  17. Antibodies to variant antigens on the surfaces of infected erythrocytes are associated with protection from malaria in Ghanaian children

    DEFF Research Database (Denmark)

    Dodoo, D; Staalsoe, T; Giha, H;

    2001-01-01

    Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a variant antigen expressed on the surface of infected erythrocytes. Each parasite genome contains about 40 PfEMP1 genes, but only 1 PfEMP1 gene is expressed at a given time. PfEMP1 serves as a parasite-sequestering ligand...... to endothelial cells and enables the parasites to avoid splenic passage. PfEMP1 antibodies may protect from disease by inhibiting sequestration, thus facilitating the destruction of infected erythrocytes in the spleen. In this study, we have measured antibodies in Ghanaian children to a conserved region of Pf......EMP1 by enzyme-linked immunosorbent assay and antibodies to variant molecules on erythrocytes infected with field isolates of P. falciparum by flow cytometry. Based on close clinical monitoring, the children were grouped into those who did (susceptible) and those who did not (protected) have malaria...

  18. Brucella abortus Omp19 recombinant protein subcutaneously co-delivered with an antigen enhances antigen-specific T helper 1 memory responses and induces protection against parasite challenge.

    Science.gov (United States)

    Coria, Lorena M; Ibañez, Andrés E; Pasquevich, Karina A; Cobiello, Paula L González; Frank, Fernanda M; Giambartolomei, Guillermo H; Cassataro, Juliana

    2016-01-20

    The discovery of effective adjuvants for many vaccines especially those with limited commercial appeal, such as vaccines to poverty-related diseases, is required. In this work, we demonstrated that subcutaneous co-administration of mice with the outer membrane protein U-Omp19 from Brucella spp. plus OVA as antigen (Ag) increases Ag-specific T cell proliferation and T helper (Th) 1 immune responses in vitro and in vivo. U-Omp19 treated dendritic cells promote IFN-γ production by specific CD4(+) T cells and increases T cell proliferation. U-Omp19 co-administration induces the production of Ag specific effector memory T cell populations (CD4(+) CD44(high) CD62L(low) T cells). Finally, subcutaneous co-administration of U-Omp19 with Trypanosoma cruzi Ags confers protection against virulent parasite challenge, reducing parasitemia and weight loss while increasing mice survival. These results indicate that the bacterial protein U-Omp19 when delivered subcutaneously could be a suitable component of vaccine formulations against infectious diseases requiring Th1 immune responses.

  19. Intramuscular delivery of adenovirus serotype 5 vector expressing humanized protective antigen induces rapid protection against anthrax that may bypass intranasally originated preexisting adenovirus immunity.

    Science.gov (United States)

    Wu, Shipo; Zhang, Zhe; Yu, Rui; Zhang, Jun; Liu, Ying; Song, Xiaohong; Yi, Shaoqiong; Liu, Ju; Chen, Jianqin; Yin, Ying; Xu, Junjie; Hou, Lihua; Chen, Wei

    2014-02-01

    Developing an effective anthrax vaccine that can induce a rapid and sustained immune response is a priority for the prevention of bioterrorism-associated anthrax infection. Here, we developed a recombinant replication-deficient adenovirus serotype 5-based vaccine expressing the humanized protective antigen (Ad5-PAopt). A single intramuscular injection of Ad5-PAopt resulted in rapid and robust humoral and cellular immune responses in Fisher 344 rats. Animals intramuscularly inoculated with a single dose of 10⁸ infectious units of Ad5-PAopt achieved 100% protection from challenge with 10 times the 50% lethal dose (LD₅₀) of anthrax lethal toxin 7 days after vaccination. Although preexisting intranasally induced immunity to Ad5 slightly weakened the humoral and cellular immune responses to Ad5-PAopt via intramuscular inoculation, 100% protection was achieved 15 days after vaccination in Fisher 344 rats. The protective efficacy conferred by intramuscular vaccination in the presence of preexisting intranasally induced immunity was significantly better than that of intranasal delivery of Ad5-PAopt and intramuscular injection with recombinant PA and aluminum adjuvant without preexisting immunity. As natural Ad5 infection often occurs via the mucosal route, the work here largely illuminates that intramuscular inoculation with Ad5-PAopt can overcome the negative effects of immunity induced by prior adenovirus infection and represents an efficient approach for protecting against emerging anthrax.

  20. Recombinant vesicular stomatitis virus-based dengue-2 vaccine candidate induces humoral response and protects mice against lethal infection.

    Science.gov (United States)

    Lauretti, Flavio; Chattopadhyay, Anasuya; de Oliveira França, Rafael Freitas; Castro-Jorge, Luiza; Rose, John; Fonseca, Benedito A L da

    2016-09-01

    Dengue is the most important arbovirus disease throughout the world and it is responsible for more than 500,000 dengue hemorrhagic cases and 22,000 deaths every year. One vaccine was recently licensed for human use in Brazil, Mexico and Philippines and although at least seven candidates have been in clinical trials the results of the most developed CYD vaccine have demonstrated immunization problems, such as uneven protection and interference between serotypes. We constructed a vaccine candidate based on vesicular stomatitis virus (VSV) expression of pre-membrane (prM) and envelope (E) proteins of dengue-2 virus (DENV-2) and tested it in mice to evaluate immunogenicity and protection against DENV-2 infection. VSV has been successfully used as vaccine vectors for several viruses to induce strong humoral and cellular immune responses. The VSV-DENV-2 recombinant was constructed by inserting the DENV-2 structural proteins into a VSV plasmid DNA for recombinant VSV-DENV-2 recovery. Infectious recombinant VSV viruses were plaque purified and prM and E expression were confirmed by immunofluorescence and radiolabeling of proteins of infected cells. Forty Balb/C mice were inoculated through subcutaneous (s.c.) route with VSV-DENV-2 vaccine in a two doses schedule 15 d apart and 29 d after first inoculation, sera were collected and the mice were challenged with 50 lethal doses (LD50) of a neurovirulent DENV-2. The VSV-DENV-2 induced anti-DENV-2 antibodies and protected animals in the challenge experiment comparable to DENV-2 immunization control group. We conclude that VSV is a promising platform to test as a DENV vaccine and perhaps against others Flaviviridae.

  1. Evaluation of eight live attenuated vaccine candidates for protection against challenge with virulent Mycobacterium avium subspecies paratuberculosis in mice

    Directory of Open Access Journals (Sweden)

    John P Bannantine

    2014-07-01

    Full Text Available Johne’s disease is caused by Mycobacterium avium subsp. paratuberculosis (MAP, which results in serious economic losses worldwide in farmed livestock such as cattle, sheep and goats. To control this disease, an effective vaccine with minimal adverse effects is needed. In order to identify a live vaccine for Johne’s disease, we evaluated eight attenuated mutant strains of MAP using a C57BL/6 mouse model. The persistence of the vaccine candidates was measured at 6, 12, and 18 weeks post vaccination. Only strains 320, 321 and 329 colonized both the liver and spleens up until the 12-week time point. The remaining five mutants showed no survival in those tissues, indicating their complete attenuation in the mouse model. The candidate vaccine strains demonstrated different levels of protection based on colonization of the challenge strain in liver and spleen tissues at 12 and 18 weeks post vaccination. Based on total MAP burden in both tissues at both time points, strain 315 (MAP1566::Tn5370 was the most protective whereas strain 318 (intergenic Tn5367 insertion between MAP0282c and MAP0283c had the most colonization. Mice vaccinated with an undiluted commercial vaccine preparation displayed the highest bacterial burden as well as enlarged spleens indicative of a strong infection. Selected vaccine strains that showed promise in the mouse model were moved forward into a goat challenge model. The results suggest that the mouse trial, as conducted, may have a relatively poor predictive value for protection in a ruminant host such as goats.

  2. Immunogenicity and protective efficacy of recombinant Modified Vaccinia virus Ankara candidate vaccines delivering West Nile virus envelope antigens

    NARCIS (Netherlands)

    Volz, Asisa; Lim, Stephanie; Kaserer, Martina; Pijlman, Gorben P.

    2016-01-01

    West Nile virus (WNV) cycles between insects and wild birds, and is transmitted via mosquito vectors to horses and humans, potentially causing severe neuroinvasive disease. Modified Vaccinia virus Ankara (MVA) is an advanced viral vector for developing new recombinant vaccines against infectious

  3. Identification of pre-erythrocytic malaria antigens that target hepatocytes for killing in vivo and contribute to protection elicited by whole-parasite vaccination.

    Directory of Open Access Journals (Sweden)

    Lin Chen

    Full Text Available Pre-erythrocytic malaria vaccines, including those based on whole-parasite approaches, have shown protective efficacy in animal and human studies. However few pre-erythocytic antigens other than the immunodominant circumsporozoite protein (CSP have been studied in depth with the goal of developing potent subunit malaria vaccines that are suited for use in endemic areas. Here we describe a novel technique to identify pre-erythrocytic malaria antigens that contribute to protection elicited by whole-parasite vaccination in the mouse model. Our approach combines immunization with genetically attenuated parasites and challenge with DNA plasmids encoding for potential protective pre-erythrocytic malaria antigens as luciferase fusions by hydrodynamic tail vein injection. After optimizing the technique, we first showed that immunization with Pyfabb/f-, a P. yoelii genetically attenuated parasite, induces killing of CSP-presenting hepatocytes. Depletion of CD8+ but not CD4+ T cells diminished the killing of CSP-expressing hepatocytes, indicating that killing is CD8+ T cell-dependent. Finally we showed that the use of heterologous prime/boost immunization strategies that use genetically attenuated parasites and DNA vaccines enabled the characterization of a novel pre-erythrocytic antigen, Tmp21, as a contributor to Pyfabb/f- induced protection. This technique will be valuable for identification of potentially protective liver stage antigens and has the potential to contribute to the understanding of immunity elicited by whole parasite vaccination, as well as the development of effective subunit malaria vaccines.

  4. Phase variable O antigen biosynthetic genes control expression of the major protective antigen and bacteriophage receptor in Vibrio cholerae O1.

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    Kimberley D Seed

    2012-09-01

    Full Text Available The Vibrio cholerae lipopolysaccharide O1 antigen is a major target of bacteriophages and the human immune system and is of critical importance for vaccine design. We used an O1-specific lytic bacteriophage as a tool to probe the capacity of V. cholerae to alter its O1 antigen and identified a novel mechanism by which this organism can modulate O antigen expression and exhibit intra-strain heterogeneity. We identified two phase variable genes required for O1 antigen biosynthesis, manA and wbeL. manA resides outside of the previously recognized O1 antigen biosynthetic locus, and encodes for a phosphomannose isomerase critical for the initial step in O1 antigen biosynthesis. We determined that manA and wbeL phase variants are attenuated for virulence, providing functional evidence to further support the critical role of the O1 antigen for infectivity. We provide the first report of phase variation modulating O1 antigen expression in V. cholerae, and show that the maintenance of these phase variable loci is an important means by which this facultative pathogen can generate the diverse subpopulations of cells needed for infecting the host intestinal tract and for escaping predation by an O1-specific phage.

  5. Intranasal Immunization with Influenza Virus-Like Particles Containing Membrane-Anchored Cholera Toxin B or Ricin Toxin B Enhances Adaptive Immune Responses and Protection against an Antigenically Distinct Virus.

    Science.gov (United States)

    Ji, Xianliang; Ren, Zhiguang; Xu, Na; Meng, Lingnan; Yu, Zhijun; Feng, Na; Sang, Xiaoyu; Li, Shengnan; Li, Yuanguo; Wang, Tiecheng; Zhao, Yongkun; Wang, Hualei; Zheng, Xuexing; Jin, Hongli; Li, Nan; Yang, Songtao; Cao, Jinshan; Liu, Wensen; Gao, Yuwei; Xia, Xianzhu

    2016-04-21

    Vaccination is the most effective means to prevent influenza virus infection, although current approaches are associated with suboptimal efficacy. Here, we generated virus-like particles (VLPs) composed of the hemagglutinin (HA), neuraminidase (NA) and matrix protein (M1) of A/Changchun/01/2009 (H1N1) with or without either membrane-anchored cholera toxin B (CTB) or ricin toxin B (RTB) as molecular adjuvants. The intranasal immunization of mice with VLPs containing membrane-anchored CTB or RTB elicited stronger humoral and cellular immune responses when compared to mice immunized with VLPs alone. Administration of VLPs containing CTB or RTB significantly enhanced virus-specific systemic and mucosal antibody responses, hemagglutination inhibiting antibody titers, virus neutralizing antibody titers, and the frequency of virus-specific IFN-γ and IL-4 secreting splenocytes. VLPs with and without CTB or RTB conferred complete protection against lethal challenge with a mouse-adapted homologous virus. When challenged with an antigenically distinct H1N1 virus, all mice immunized with VLPs containing CTB or RTB survived whereas mice immunized with VLPs alone showed only partial protection (80% survival). Our results suggest that membrane-anchored CTB and RTB possess strong adjuvant properties when incorporated into an intranasally-delivered influenza VLP vaccine. Chimeric influenza VLPs containing CTB or RTB may represent promising vaccine candidates for improved immunological protection against homologous and antigenically distinct influenza viruses.

  6. Positive correlation between Aeromonas salmonicida vaccine antigen concentration and protection in vaccinated rainbow trout Oncorhynchus mykiss evaluated by a tail fin infection model

    DEFF Research Database (Denmark)

    Marana, M. H.; Skov, J.; Chettri, Jiwan Kumar;

    2016-01-01

    Rainbow trout, Oncorhynchus mykiss (Walbaum), are able to raise a protective immune response against Aeromonas salmonicida subsp. salmonicida (AS) following injection vaccination with commercial vaccines containing formalin-killed bacteria, but the protection is often suboptimal under Danish...... mariculture conditions. We elucidated whether protection can be improved by increasing the concentration of antigen (formalin-killed bacteria) in the vaccine. Rainbow trout juveniles were vaccinated by intraperitoneal (i.p.) injection with a bacterin of Aeromonas salmonicida subsp. salmonicida strain 090710...

  7. Results from tandem Phase 1 studies evaluating the safety, reactogenicity and immunogenicity of the vaccine candidate antigen Plasmodium falciparum FVO merozoite surface protein-1 (MSP142 administered intramuscularly with adjuvant system AS01

    Directory of Open Access Journals (Sweden)

    Otsyula Nekoye

    2013-01-01

    Full Text Available Abstract Background The development of an asexual blood stage vaccine against Plasmodium falciparum malaria based on the major merozoite surface protein-1 (MSP1 antigen is founded on the protective efficacy observed in preclinical studies and induction of invasion and growth inhibitory antibody responses. The 42 kDa C-terminus of MSP1 has been developed as the recombinant protein vaccine antigen, and the 3D7 allotype, formulated with the Adjuvant System AS02A, has been evaluated extensively in human clinical trials. In preclinical rabbit studies, the FVO allele of MSP142 has been shown to have improved immunogenicity over the 3D7 allele, in terms of antibody titres as well as growth inhibitory activity of antibodies against both the heterologous 3D7 and homologous FVO parasites. Methods Two Phase 1 clinical studies were conducted to examine the safety, reactogenicity and immunogenicity of the FVO allele of MSP142 in the adjuvant system AS01 administered intramuscularly at 0-, 1-, and 2-months: one in the USA and, after evaluation of safety data results, one in Western Kenya. The US study was an open-label, dose escalation study of 10 and 50 μg doses of MSP142 in 26 adults, while the Kenya study, evaluating 30 volunteers, was a double-blind, randomized study of only the 50 μg dose with a rabies vaccine comparator. Results In these studies it was demonstrated that this vaccine formulation has an acceptable safety profile and is immunogenic in malaria-naïve and malaria-experienced populations. High titres of anti-MSP1 antibodies were induced in both study populations, although there was a limited number of volunteers whose serum demonstrated significant inhibition of blood-stage parasites as measured by growth inhibition assay. In the US volunteers, the antibodies generated exhibited better cross-reactivity to heterologous MSP1 alleles than a MSP1-based vaccine (3D7 allele previously tested at both study sites. Conclusions Given that the primary

  8. Protection from anti-TCR/CD3-induced apoptosis in immature thymocytes by a signal through thymic shared antigen-1/stem cell antigen-2

    OpenAIRE

    1996-01-01

    During T cell development in the thymus, the expression of thymic shared antigen-1 (TSA-1)/stem cell antigen-2 (Sca-2), a glycosylphosphatidylinositol (GPI)-anchored differentiation antigen, is developmentally regulated. The expression level of TSA-1 is the highest in most immature CD4- CD8- thymocytes, high in CD4+ CD8+ thymocytes, but barely detectable in mature CD4+ CD8- or CD4- CD8- thymocytes and peripheral T cells. We have previously shown that surface TSA-1 expression in peripheral T c...

  9. Investigation of host candidate malaria-associated risk/protective SNPs in a Brazilian Amazonian population.

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    Simone da Silva Santos

    Full Text Available The Brazilian Amazon is a hypo-endemic malaria region with nearly 300,000 cases each year. A variety of genetic polymorphisms, particularly in erythrocyte receptors and immune response related genes, have been described to be associated with susceptibility and resistance to malaria. In order to identify polymorphisms that might be associated with malaria clinical outcomes in a Brazilian Amazonian population, sixty-four human single nucleotide polymorphisms in 37 genes were analyzed using a Sequenom massARRAY iPLEX platform. A total of 648 individuals from two malaria endemic areas were studied, including 535 malaria cases (113 individuals with clinical mild malaria, 122 individuals with asymptomatic infection and 300 individuals with history of previous mild malaria and 113 health controls with no history of malaria. The data revealed significant associations (p<0.003 between one SNP in the IL10 gene (rs1800896 and one SNP in the TLR4 gene (rs4986790 with reduced risk for clinical malaria, one SNP in the IRF1 gene (rs2706384 with increased risk for clinical malaria, one SNP in the LTA gene (rs909253 with protection from clinical malaria and one SNP in the TNF gene (RS1800750 associated with susceptibility to clinical malaria. Also, a new association was found between a SNP in the CTL4 gene (rs2242665, located at the major histocompatibility complex III region, and reduced risk for clinical malaria. This study represents the first association study from an Amazonian population involving a large number of host genetic polymorphisms with susceptibility or resistance to Plasmodium infection and malaria outcomes. Further studies should include a larger number of individuals, refined parameters and a fine-scale map obtained through DNA sequencing to increase the knowledge of the Amazonian population genetic diversity.

  10. Cationic liposomes containing soluble Leishmania antigens (SLA) plus CpG ODNs induce protection against murine model of leishmaniasis.

    Science.gov (United States)

    Heravi Shargh, Vahid; Jaafari, Mahmoud Reza; Khamesipour, Ali; Jalali, Seyed Amir; Firouzmand, Hengameh; Abbasi, Azam; Badiee, Ali

    2012-07-01

    Development of an effective vaccine against leishmaniasis is possible due to the fact that individuals cured from cutaneous leishmaniasis (CL) are protected from further infection. First generation Leishmania vaccines consisting of whole killed parasites reached to phase 3 clinical trials but failed to show enough efficacies mainly due to the lack of an appropriate adjuvant. In this study, an efficient liposomal protein-based vaccine against Leishmania major infection was developed using soluble Leishmania antigens (SLA) as a first generation vaccine and cytidine phosphate guanosine oligodeoxynucleotides (CpG ODNs) as an immunostimulatory adjuvant. 1, 2-Dioleoyl-3-trimethylammonium-propane was used as a cationic lipid to prepare the liposomes due to its intrinsic adjuvanticity. BALB/c mice were immunized subcutaneously (SC), three times in 2-week intervals, with Lip-SLA-CpG, Lip-SLA, SLA + CpG, SLA, or HEPES buffer. As criteria for protection, footpad swelling at the site of challenge and spleen parasite loads were assessed, and the immune responses were evaluated by determination of IFN-γ and IL-4 levels of cultured splenocytes, and IgG subtypes. The group of mice that received Lip-SLA-CpG showed a significantly smaller footpad swelling, lower spleen parasite burden, higher IgG2a antibody, and lower IL-4 level compared to the control groups. It is concluded that cationic liposomes containing SLA and CpG ODNs are appropriate to induce Th1 type of immune response and protection against leishmaniasis.

  11. Construction of Recombinant Baculoviruses Expressing Infectious Bursal Disease Virus Main Protective Antigen and Their Immune Effects on Chickens.

    Directory of Open Access Journals (Sweden)

    Jingping Ge

    Full Text Available In order to overcome the limitations of conventional vaccines for infectious bursal disease virus (IBDV, we constructed recombinant dual expression system baculoviruses with VP2 and VP2/4/3, the main protective antigens of IBDV. We compared the immune effects of the baculoviruses in avian cells and detected their control effects on chickens with infectious bursal disease. We used Western blot analysis to measure VP2 protein and VP2/4/3 polyprotein expression in avian cells infected using the Bac-to-Bac baculovirus expression system. The recombinant baculoviruses were used to vaccinate specific pathogen-free chickens, which produced specific protective antibodies and strong cellular immune responses. The results of the virus challenge experiment revealed that the protective efficiency of VP2 and VP2/4/3 virus vaccines were 95.8% and 100%, respectively, both of which were higher than the vaccine group (87.5%, and significantly higher than the control group (50%. The results demonstrated that the immune effect of BV-S-ITRs-VP2/4/3 was superior to that of BV-S-ITRs-VP2. Compared with traditional attenuated vaccine and genetically engineered live vector vaccine, the dual expression viral vector vaccine has good bio-safety. The results of this study provide a foundation for the further development of poultry vaccines, in addition to providing a useful reference for developing non-replicating live vaccines against other viral diseases.

  12. Blood stage malaria vaccine eliciting high antigen-specific antibody concentrations confers no protection to young children in Western Kenya.

    Directory of Open Access Journals (Sweden)

    Bernhards R Ogutu

    Full Text Available The antigen, falciparum malaria protein 1 (FMP1, represents the 42-kDa C-terminal fragment of merozoite surface protein-1 (MSP-1 of the 3D7 clone of P. falciparum. Formulated with AS02 (a proprietary Adjuvant System, it constitutes the FMP1/AS02 candidate malaria vaccine. We evaluated this vaccine's safety, immunogenicity, and efficacy in African children.A randomised, double-blind, Phase IIb, comparator-controlled trial.The trial was conducted in 13 field stations of one mile radii within Kombewa Division, Nyanza Province, Western Kenya, an area of holoendemic transmission of P. falciparum. We enrolled 400 children aged 12-47 months in general good health.Children were randomised in a 1ratio1 fashion to receive either FMP1/AS02 (50 microg or Rabipur(R rabies vaccine. Vaccinations were administered on a 0, 1, and 2 month schedule. The primary study endpoint was time to first clinical episode of P. falciparum malaria (temperature >/=37.5 degrees C with asexual parasitaemia of >/=50,000 parasites/microL of blood occurring between 14 days and six months after a third dose. Case detection was both active and passive. Safety and immunogenicity were evaluated for eight months after first immunisations; vaccine efficacy (VE was measured over a six-month period following third vaccinations.374 of 400 children received all three doses and completed six months of follow-up. FMP1/AS02 had a good safety profile and was well-tolerated but more reactogenic than the comparator. Geometric mean anti-MSP-1(42 antibody concentrations increased from1.3 microg/mL to 27.3 microg/mL in the FMP1/AS02 recipients, but were unchanged in controls. 97 children in the FMP1/AS02 group and 98 controls had a primary endpoint episode. Overall VE was 5.1% (95% CI: -26% to +28%; p-value = 0.7.FMP1/AS02 is not a promising candidate for further development as a monovalent malaria vaccine. Future MSP-1(42 vaccine development should focus on other formulations and antigen constructs

  13. No protection in chickens immunized by the oral or intra-muscular immunization route with Ascaridia galli soluble antigen

    DEFF Research Database (Denmark)

    Andersen, Janne Pleidrup; Norup, Liselotte R.; Dalgaard, Tina S.

    2013-01-01

    In chickens, the nematode Ascaridia galli is found with prevalences of up to 100% causing economic losses to farmers. No avian nematode vaccines have yet been developed and detailed knowledge about the chicken immune response towards A. galli is therefore of great importance. The objective...... of this study was to evaluate the induction of protective immune responses to A. galli soluble antigen by different immunization routes. Chickens were immunized with a crude extract of A. galli via an oral or intra-muscular route using cholera toxin B subunit as adjuvant and subsequently challenged with A....... galli. Only chickens immunized via the intra-muscular route developed a specific A. galli antibody response. Frequencies of γδ T cells in spleen were higher 7 days after the first immunization in both groups but only significantly so in the intra-muscularly immunized group. In addition, systemic...

  14. Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of SpyCEP, a candidate antigen for a vaccine against Streptococcus pyogenes.

    Science.gov (United States)

    Abate, Francesca; Malito, Enrico; Falugi, Fabiana; Margarit Y Ros, Immaculada; Bottomley, Matthew James

    2013-10-01

    Streptococcus pyogenes (Group A streptococcus; GAS) is an important human pathogen against which an effective vaccine does not yet exist. The S. pyogenes protein SpyCEP (S. pyogenes cell-envelope proteinase) is a surface-exposed subtilisin-like serine protease of 1647 amino acids. In addition to its auto-protease activity, SpyCEP is capable of cleaving interleukin 8 and related chemokines, contributing to GAS immune-evasion strategies. SpyCEP is immunogenic and confers protection in animal models of GAS infections. In order to structurally characterize this promising vaccine candidate, several SpyCEP protein-expression constructs were designed, cloned, produced in Escherichia coli, purified by affinity chromatography and subjected to crystallization trials. Crystals of a selenomethionyl form of a near-full-length SpyCEP ectodomain were obtained. The crystals diffracted X-rays to 3.3 Å resolution and belonged to space group C2, with unit-cell parameters a=139.2, b=120.4, c=104.3 Å, β=111°.

  15. Secretion of protective antigens by tissue-stage nematode larvae revealed by proteomic analysis and vaccination-induced sterile immunity.

    Science.gov (United States)

    Hewitson, James P; Ivens, Al C; Harcus, Yvonne; Filbey, Kara J; McSorley, Henry J; Murray, Janice; Bridgett, Stephen; Ashford, David; Dowle, Adam A; Maizels, Rick M

    2013-08-01

    Gastrointestinal nematode parasites infect over 1 billion humans, with little evidence for generation of sterilising immunity. These helminths are highly adapted to their mammalian host, following a developmental program through successive niches, while effectively down-modulating host immune responsiveness. Larvae of Heligmosomoides polygyrus, for example, encyst in the intestinal submucosa, before emerging as adult worms into the duodenal lumen. Adults release immunomodulatory excretory-secretory (ES) products, but mice immunised with adult H. polygyrus ES become fully immune to challenge infection. ES products of the intestinal wall 4th stage (L4) larvae are similarly important in host-parasite interactions, as they readily generate sterile immunity against infection, while released material from the egg stage is ineffective. Proteomic analyses of L4 ES identifies protective antigen targets as well as potential tissue-phase immunomodulatory molecules, using as comparators the adult ES proteome and a profile of H. polygyrus egg-released material. While 135 proteins are shared between L4 and adult ES, 72 are L4 ES-specific; L4-specific proteins correspond to those whose transcription is restricted to larval stages, while shared proteins are generally transcribed by all life cycle forms. Two protein families are more heavily represented in the L4 secretome, the Sushi domain, associated with complement regulation, and the ShK/SXC domain related to a toxin interfering with T cell signalling. Both adult and L4 ES contain extensive but distinct arrays of Venom allergen/Ancylostoma secreted protein-Like (VAL) members, with acetylcholinesterases (ACEs) and apyrase APY-3 particularly abundant in L4 ES. Serum antibodies from mice vaccinated with L4 and adult ES react strongly to the VAL-1 protein and to ACE-1, indicating that these two antigens represent major vaccine targets for this intestinal nematode. We have thus defined an extensive and novel repertoire of H

  16. Secretion of protective antigens by tissue-stage nematode larvae revealed by proteomic analysis and vaccination-induced sterile immunity.

    Directory of Open Access Journals (Sweden)

    James P Hewitson

    2013-08-01

    Full Text Available Gastrointestinal nematode parasites infect over 1 billion humans, with little evidence for generation of sterilising immunity. These helminths are highly adapted to their mammalian host, following a developmental program through successive niches, while effectively down-modulating host immune responsiveness. Larvae of Heligmosomoides polygyrus, for example, encyst in the intestinal submucosa, before emerging as adult worms into the duodenal lumen. Adults release immunomodulatory excretory-secretory (ES products, but mice immunised with adult H. polygyrus ES become fully immune to challenge infection. ES products of the intestinal wall 4th stage (L4 larvae are similarly important in host-parasite interactions, as they readily generate sterile immunity against infection, while released material from the egg stage is ineffective. Proteomic analyses of L4 ES identifies protective antigen targets as well as potential tissue-phase immunomodulatory molecules, using as comparators the adult ES proteome and a profile of H. polygyrus egg-released material. While 135 proteins are shared between L4 and adult ES, 72 are L4 ES-specific; L4-specific proteins correspond to those whose transcription is restricted to larval stages, while shared proteins are generally transcribed by all life cycle forms. Two protein families are more heavily represented in the L4 secretome, the Sushi domain, associated with complement regulation, and the ShK/SXC domain related to a toxin interfering with T cell signalling. Both adult and L4 ES contain extensive but distinct arrays of Venom allergen/Ancylostoma secreted protein-Like (VAL members, with acetylcholinesterases (ACEs and apyrase APY-3 particularly abundant in L4 ES. Serum antibodies from mice vaccinated with L4 and adult ES react strongly to the VAL-1 protein and to ACE-1, indicating that these two antigens represent major vaccine targets for this intestinal nematode. We have thus defined an extensive and novel

  17. Binding to histo-blood group antigen-expressing bacteria protects human norovirus from acute heat stress

    Directory of Open Access Journals (Sweden)

    Dan eLi

    2015-07-01

    Full Text Available This study aims to investigate if histo-blood group antigen (HBGA expressing bacteria have any protective role on human norovirus (NoV from acute heat stress. Eleven bacterial strains were included, belonging to Escherichia coli, Enterobacter cloacae, Enterobacter aerogenes, Clostridium difficile, Bifidobacterium adolescentis, and Bifidobacterium longum. HBGA expression of the bacteria as well as binding of human NoV virus-like particles (VLPs, GI.1 and GII.4 strains to the bacteria were detected by flow cytometry. NoV VLPs pre-incubated with HBGA expressing or non-HBGA expressing bacteria were heated and detected by both direct ELISA and porcine gastric mucin-binding assay. The NoV-binding abilities of the bacteria correlated well with their HBGA expression profiles. Two HBGA expressing E.coli (LMG8223 and LFMFP861, both GI.1 and GII.4 binders and one non-HBGA expressing E.coli (ATCC8739, neither GI.1 nor GII.4 binder were selected for the heat treatment test with NoV VLPs. Compared with the same cell numbers of non-HBGA expressing E.coli, the presence of HBGA-expressing E.coli could always maintain higher antigen integrity, as well as mucin-binding ability of NoV VLPs of both GI.1 and GII.4 after heat-treatment at 90°C for 2 min. These results indicate that HBGA-expressing bacteria may protect NoVs during the food processing treatments, thereby facilitating their transmission.

  18. Protective antibodies against Taenia taeniaeformis in rats infected with eggs or injected with non-viable oncospheres or recombinant antigens of oncospheres.

    Science.gov (United States)

    Ito, A; Asano, K; Okamoto, K

    1994-09-01

    Antibody responses against Taenia taeniaeformis in rats infected with eggs or injected with non-viable oncospheres or recombinant antigens of oncospheres were analysed by passive transfer of serum and Western blotting. When recipient rats were injected with 1 ml serum from donors infected with eggs (infected serum), they all showed complete resistance to oral egg challenge, whereas those injected with 1 ml serum from donors injected with either oncospheres or recombinant antigens (vaccinated serum) showed no resistance. IgG and IgG subclass responses detected by Western blotting revealed that antibody responses to oncosphere antigens in infected serum thoroughly differed from those in vaccinated serum. It is suggested that IgG2 alpha responses in infected serum should be used for screening of epitopes for candidate vaccine.

  19. rBCG30-induced immunity and cross-protection against Mycobacterium leprae challenge are enhanced by boosting with the Mycobacterium tuberculosis 30-kilodalton antigen 85B.

    Science.gov (United States)

    Gillis, Thomas P; Tullius, Michael V; Horwitz, Marcus A

    2014-09-01

    Leprosy remains a major global health problem and typically occurs in regions in which tuberculosis is endemic. Vaccines are needed that protect against both infections and do so better than the suboptimal Mycobacterium bovis BCG vaccine. Here, we evaluated rBCG30, a vaccine previously demonstrated to induce protection superior to that of BCG against Mycobacterium tuberculosis and Mycobacterium bovis challenge in animal models, for efficacy against Mycobacterium leprae challenge in a murine model of leprosy. rBCG30 overexpresses the M. tuberculosis 30-kDa major secretory protein antigen 85B, which is 85% homologous with the M. leprae homolog (r30ML). Mice were sham immunized or immunized intradermally with BCG or rBCG30 and challenged 2.5 months later by injection of viable M. leprae into each hind footpad. After 7 months, vaccine efficacy was assessed by enumerating the M. leprae bacteria per footpad. Both BCG and rBCG30 induced significant protection against M. leprae challenge. In the one experiment in which a comparison between BCG and rBCG30 was feasible, rBCG30 induced significantly greater protection than did BCG. Immunization of mice with purified M. tuberculosis or M. leprae antigen 85B also induced protection against M. leprae challenge but less so than BCG or rBCG30. Notably, boosting rBCG30 with M. tuberculosis antigen 85B significantly enhanced r30ML-specific immune responses, substantially more so than boosting BCG, and significantly augmented protection against M. leprae challenge. Thus, rBCG30, a vaccine that induces improved protection against M. tuberculosis, induces cross-protection against M. leprae that is comparable or potentially superior to that induced by BCG, and boosting rBCG30 with antigen 85B further enhances immune responses and protective efficacy.

  20. Novel recombinant DNA vaccine candidates for human respiratory syncytial virus: Preclinical evaluation of immunogenicity and protection efficiency.

    Science.gov (United States)

    Farrag, Mohamed A; Amer, Haitham M; Öhlschläger, Peter; Hamad, Maaweya E; Almajhdi, Fahad N

    2017-03-08

    The development of safe and potent vaccines for human respiratory syncytial virus (HRSV) is still a challenge for researchers worldwide. DNA-based immunization is currently a promising approach that has been used to generate human vaccines for different age groups. In this study, novel HRSV DNA vaccine candidates were generated and preclinically tested in BALB/c mice. Three different versions of the codon-optimized HRSV fusion (F) gene were individually cloned into the pPOE vector. The new recombinant vectors either express full-length (pPOE-F), secretory (pPOE-TF), or M282-90 linked (pPOE-FM2) forms of the F protein. Distinctive expression of the F protein was identified in HEp-2 cells transfected with the different recombinant vectors using ELISA and immunofluorescence. Mice immunization verified the potential for recombinant vectors to elicit significant levels of neutralizing antibodies and CD8(+) T-cell lymphocytes. pPOE-TF showed higher levels of gene expression in cell culture and better induction of the humoral and cellular immune responses. Following virus challenge, mice that had been immunized with the recombinant vectors were able to control virus replication and displayed lower inflammation compared with mice immunized with empty pPOE vector or formalin-inactivated HRSV vaccine. Moreover, pulmonary cytokine profiles of mice immunized with the 3 recombinant vectors were similar to those of the mock infected group. In conclusion, recombinant pPOE vectors are promising HRSV vaccine candidates in terms of their safety, immunogenicity and protective efficiency. These data encourage further evaluation in phase I clinical trials.

  1. The highly antigenic 53/25 kDa Taenia solium protein fraction with cathepsin-L like activity is present in the oncosphere/cysticercus and induces non-protective IgG antibodies in pigs.

    Science.gov (United States)

    Zimic, Mirko; Pajuelo, Mónica; Gilman, Robert H; Gutiérrez, Andrés H; Rueda, Luis D; Flores, Myra; Chile, Nancy; Verástegui, Manuela; Gonzalez, Armando; García, Héctor H; Sheen, Patricia

    2012-01-15

    Cathepsin L-like proteases are secreted by several parasites including Taenia solium. The mechanism used by T. solium oncospheres to degrade and penetrate the intestine and infect the host is incompletely understood. It is assumed that intestinal degradation is driven by the proteolytic activity of enzymes secreted by the oncosphere. Blocking the proteolytic activity by an antibody response would prevent the oncosphere penetration and further infection. Serine and cysteine proteases including chymotrypsin, trypsin, elastase, and cathepsin L, are secreted by T. solium and Taenia saginata oncospheres when cultured in vitro, being potential vaccine candidates. However, the purification of a sufficient quantity of proteases secreted by oncospheres to conduct a vaccine trial is costly and lengthy. A 53/25 kDa cathepsin L-like fraction partially purified from T. solium cyst fluid was described previously as an important antigen for immunodiagnostics. In this study we found that this antigen is present in the T. solium oncosphere and is also secreted by the cysticercus. This protein fraction was tested for its ability to protect pigs against an oral challenge with T. solium oncospheres in a vaccine trial. IgG antibodies against the 53/25 kDa cathepsin L-like protein fraction were elicited in the vaccinated animals but did not confer protection.

  2. Adenoviral Expression of a Bispecific VHH-Based Neutralizing Agent That Targets Protective Antigen Provides Prophylactic Protection from Anthrax in Mice.

    Science.gov (United States)

    Moayeri, Mahtab; Tremblay, Jacqueline M; Debatis, Michelle; Dmitriev, Igor P; Kashentseva, Elena A; Yeh, Anthony J; Cheung, Gordon Y C; Curiel, David T; Leppla, Stephen; Shoemaker, Charles B

    2016-01-06

    Bacillus anthracis, the causative agent of anthrax, secretes three polypeptides, which form the bipartite lethal and edema toxins (LT and ET, respectively). The common component in these toxins, protective antigen (PA), is responsible for binding to cellular receptors and translocating the lethal factor (LF) and edema factor (EF) enzymatic moieties to the cytosol. Antibodies against PA protect against anthrax. We previously isolated toxin-neutralizing variable domains of camelid heavy-chain-only antibodies (VHHs) and demonstrated their in vivo efficacy. In this work, gene therapy with an adenoviral (Ad) vector (Ad/VNA2-PA) (VNA, VHH-based neutralizing agents) promoting the expression of a bispecific VHH-based neutralizing agent (VNA2-PA), consisting of two linked VHHs targeting different PA-neutralizing epitopes, was tested in two inbred mouse strains, BALB/cJ and C57BL/6J, and found to protect mice against anthrax toxin challenge and anthrax spore infection. Two weeks after a single treatment with Ad/VNA2-PA, serum VNA2-PA levels remained above 1 μg/ml, with some as high as 10 mg/ml. The levels were 10- to 100-fold higher and persisted longer in C57BL/6J than in BALB/cJ mice. Mice were challenged with a lethal dose of LT or spores at various times after Ad/VNA2-PA administration. The majority of BALB/cJ mice having serum VNA2-PA levels of >0.1 μg/ml survived LT challenge, and 9 of 10 C57BL/6J mice with serum levels of >1 μg/ml survived spore challenge. Our findings demonstrate the potential for genetic delivery of VNAs as an effective method for providing prophylactic protection from anthrax. We also extend prior findings of mouse strain-based differences in transgene expression and persistence by adenoviral vectors.

  3. Preparation and evaluation of unimolecular pentavalent and hexavalent antigenic constructs targeting prostate and breast cancer: a synthetic route to anticancer vaccine candidates.

    Science.gov (United States)

    Ragupathi, Govind; Koide, Fusataka; Livingston, Philip O; Cho, Young Shin; Endo, Atsushi; Wan, Qian; Spassova, Maria K; Keding, Stacy J; Allen, Jennifer; Ouerfelli, Ouathek; Wilson, Rebecca M; Danishefsky, Samuel J

    2006-03-01

    Several novel, fully synthetic, carbohydrate-based antitumor vaccines have been assembled. Each construct consists of multiple cancer-related antigens displayed on a single polypeptide backbone. Recent advances in synthetic methodology have allowed for the incorporation of a complex oligosaccharide terminating in a sialic acid residue (i.e., GM2) as one of the carbohydrate antigens. Details of the vaccine synthesis as well as the results of preliminary immunological investigations are described herein.

  4. 囊虫病免疫诊断候选抗原研究进展%Advances in research on candidate antigens for immunodiagnosis of cysticercosis

    Institute of Scientific and Technical Information of China (English)

    王燕

    2011-01-01

    猪囊尾蚴免疫诊断抗原的研究是囊虫病免疫诊断的基础.猪囊尾蚴抗原成分复杂,特别是虫体粗抗原,与多种寄生虫存在明显的交叉抗原成分,影响检测的特异性.近年来随着分子生物学的发展,重组抗原制备简单,检测效果良好,已成为囊虫病免疫诊断研究的热点.本文对近年来囊虫病免疫诊断抗原的分子生物学研究进展进行了综述.%Study of the antigens of Taenia solium is the basis for immunodiagnosis of cysticercosis. Taenia solium antigens have a number of components, which is particularly true of the parasite's crude antigens. Cross-reactivity with other helminth infections occurs with whole worm antigen and affects the specificity of the parasitr's detection. Immunodiagnosis of cysticercosis has garnered attention because of recent advances in molecular biology, ready preparation of recombinant antigens, and the increased effectiveness of the disease's detection. This review describes recent advances in molecular biology research on antigens for use in immunodiagnosis of cysticercosis.

  5. Recombinant Adenovirus Delivery of Calreticulin-ESAT-6 Produces an Antigen-Specific Immune Response but no Protection Against a Mycobacterium Tuberculosis Challenge

    NARCIS (Netherlands)

    Esparza-Gonzalez, S. C.; Troy, A.; Troudt, J.; Loera-Arias, M. J.; Villatoro Hernandez, Julio; Torres-Lopez, E.; Ancer-Rodriguez, J.; Gutierrez-Puente, Y.; Munoz-Maldonado, G.; Saucedo-Cardenas, O.; Montes-de-Oca-Luna, R.; Izzo, A.

    2012-01-01

    Bacillus CalmetteGuerin (BCG) has failed to efficaciously control the worldwide spread of the disease. New vaccine development targets virulence antigens of Mycobacterium tuberculosis that are deleted in Mycobacterium bovis BCG. Immunization with ESAT-6 and CFP10 provides protection against M. tuber

  6. Assessment of protective immune responses against hydatid disease in sheep by immunization with synthetic peptide antigens.

    Science.gov (United States)

    Woollard, D J; Heath, D D; Lightowlers, M W

    2000-08-01

    Four synthetic peptides which comprise the immunodominant linear epitopes of the EG95 recombinant protein, were investigated for their ability to induce host-protective immunity against Echinococcus granulosus in sheep. Sheep were immunized with either free peptide or peptide conjugated to diphtheria toxoid and challenge infected with E. granulosus eggs. All of the peptides elicited specific antibody, but these did not kill the parasite in in vitro culture assays, nor did the peptides induce protection against challenge infection. In contrast, anti-EG95 antibodies affinity purified against each of the 4 peptides were lethal to the parasite in in vitro culture. These affinity-purified antibodies were shown to contain specific antibody to both peptide and EG95. In in vitro inhibition assays, the peptides did not diminish anti-EG95 antibody binding to EG95 or parasite lysis in oncosphere killing assays. These results suggest that the fine specificities of antibodies raised against the recombinant protein are different to those raised against the peptide immunogens and that the majority of the antibody induced by vaccination with EG95 is raised against conformational determinants.

  7. Bovine leukocyte antigen major histocompatibility complex class II DRB3*2703 and DRB3*1501 alleles are associated with variation in levels of protection against Theileria parva challenge following immunization with the sporozoite p67 antigen.

    Science.gov (United States)

    Ballingall, Keith T; Luyai, Anthony; Rowlands, G John; Sales, Jill; Musoke, Anthony J; Morzaria, Subash P; McKeever, Declan J

    2004-05-01

    Initial laboratory trials of an experimental subunit vaccine against Theileria parva based on the 67-kDa major sporozoite surface antigen revealed a range of responses to challenge. We have analyzed convergence in seven sets of monozygotic twins which suggests that genetic factors may have an influence in determining the degree of protection provided by p67 immunization. In addition, we have examined whether allelic diversity at major histocompatibility complex class II loci influences protection. Analysis of bovine leukocyte antigen DRB3 diversity in 201 animals identified significant associations with vaccine success (DRB3*2703; P = 0.027) and vaccine failure (DRB3*1501; P = 0.013). Furthermore, DRB3*2703 was associated with the likelihood of immunized animals showing little to no clinical signs of disease following challenge. We discuss the acquired and innate immune mechanisms that may be behind the associations described here.

  8. Histamine release factor from Dermanyssus gallinae (De Geer): characterization and in vitro assessment as a protective antigen.

    Science.gov (United States)

    Bartley, Kathryn; Nisbet, Alasdair J; Offer, Jill E; Sparks, Nicholas H C; Wright, Harry W; Huntley, John F

    2009-03-01

    A cDNA encoding a 174-amino-acid orthologue of a tick histamine release factor (HRF) was identified from the haematophagous poultry red mite Dermanyssus gallinae. The predicted D. gallinae HRF protein (Dg-HRF-1) sequence is highly conserved with the tick HRFs (identity 52-54%) and to a lesser degree with translationally controlled tumour proteins (TCTP) from mammals and other invertebrates (range 38-47%). Phylogenetically, Dg-HRF-1 partitions with the tick HRF clade suggesting a shared linage and potentially similar function(s). A recombinant Dg-HRF-1 protein (rDg-HRF-1) was produced and shown to induce degranulation of rat peritoneal mast cells in vitro, confirming conservation of the histamine-releasing function in D. gallinae. Polyclonal antibodies were generated in rabbits and hens to rDg-HRF-1. Western blotting demonstrated that native Dg-HRF is a soluble protein and immunohistochemical staining of mite sections revealed that the distribution of Dg-HRF, although ubiquitous, is more common in mite reproductive, digestive and synganglion tissues. A survey of hens housed continuously in a mite-infested commercial poultry unit failed to identify IgY specific for recombinant or native Dg-HRF, indicating that Dg-HRF is not exposed to the host during infestation/feeding and may therefore have potential as a vaccine using the concealed antigen approach. To test the protective capability of rDg-HRF-1, fresh heparinised chicken blood was enriched with yolk-derived anti-Dg-HRF IgY antibodies and fed to semi-starved mites using an in vitro feeding system. A statistically significant increase in mortality was shown (P=0.004) in mites fed with anti-Dg-HRF IgY after just one blood meal. The work presented here demonstrates, to our knowledge for the first time, the feasibility of vaccinating hens with recombinant D. gallinae antigens to control mite infestation and the potential of rDg-HRF-1 as a vaccine antigen.

  9. Identification of immunodominant epitopes in Trypanosoma cruzi trypomastigote surface antigen-1 protein that mask protective epitopes.

    Science.gov (United States)

    Wrightsman, R A; Dawson, B D; Fouts, D L; Manning, J E

    1994-10-01

    The gene that encodes trypomastigote surface Ag-1 (TSA-1), a major surface Ag of the bloodstream trypomastigote stage of Trypanosoma cruzi, was expressed in a baculovirus expression system. To determine the epitope(s) in TSA-1 that was recognized during T. cruzi infection and after immunization with TSA-1, subregions of the TSA-1 gene were expressed in a bacterial expression system. As seen by Western blotting, both mice and rabbits immunized with recombinant TSA-1 protein, as well as T. cruzi-infected mice, developed strong immune responses to the carboxyl-proximal region of TSA-1, but show no reaction to the amino-proximal portion of TSA-1. When mice were immunized with either recombinant TSA-1 protein or the carboxyl-proximal region of TSA-1, they did not survive challenge with 10(3) bloodstream trypomastigotes. However, 70% of the mice immunized with the amino-proximal portion of TSA-1 survived challenge with 10(3) bloodstream trypomastigotes. Thus, the immune responses elicited by recombinant TSA-1 or the carboxyl-proximal portion of TSA-1 are nonprotective during T. cruzi infection. In contrast, vaccination with the amino proximal region of TSA-1 elicits a protective immune response. These results suggest that responses to immunodominant epitope(s) within the carboxyl-proximal portion of TSA-1 mask epitopes within the amino-proximal portion that are capable of stimulating host-protective immune responses. It is suggested that immunodominant regions in surface molecules such as TSA-1 may provide a mechanism for the parasite to evade the host immune response by directing the response away from epitopes that have the potential to elicit a reaction that is damaging to the parasite.

  10. Vaccination with liposomal leishmanial antigens adjuvanted with monophosphoryl lipid-trehalose dicorynomycolate (MPL-TDM) confers long-term protection against visceral leishmaniasis through a human administrable route.

    Science.gov (United States)

    Ravindran, Rajesh; Maji, Mithun; Ali, Nahid

    2012-01-01

    The development of a long-term protective subunit vaccine against visceral leishmaniasis depends on antigens and adjuvants that can induce an appropriate immune response. The immunization of leishmanial antigens alone shows limited efficacy in the absence of an appropriate adjuvant. Earlier we demonstrated sustained protection against Leishmania donovani with leishmanial antigens entrapped in cationic liposomes through an intraperitoneal route. However, this route is not applicable for human administration. Herein, we therefore evaluated the immune response and protection induced by liposomal soluble leishmanial antigen (SLA) formulated with monophosphoryl lipid-trehalose dicorynomycolate (MPL-TDM) through a subcutaneous route. Subcutaneous immunization of BALB/c mice with SLA entrapped in liposomes or with MPL-TDM elicited partial protection against experimental visceral leishmaniasis. In contrast, liposomal SLA adjuvanted with MPL-TDM induced significantly higher levels of protection in liver and spleen in BALB/c mice challenged 10 days post-vaccination. Protection conferred by this formulation was sustained up to 12 weeks of immunization, and infection was controlled for at least 4 months of the challenge, similar to liposomal SLA immunization administered intraperitoneally. An analysis of cellular immune responses of liposomal SLA + MPL-TDM immunized mice demonstrated the induction of IFN-γ and IgG2a antibody production not only 10 days or 12 weeks post-vaccination but also 4 months after the challenge infection and a down regulation of IL-4 production after infection. Moreover, long-term immunity elicited by this formulation was associated with IFN-γ production also by CD8⁺ T cells. Taken together, our results suggest that liposomal SLA + MPL-TDM represent a good vaccine formulation for the induction of durable protection against L. donovani through a human administrable route.

  11. Oral delivery of the Sj23LHD-GST antigen by Salmonella typhimurium type III secretion system protects against Schistosoma japonicum infection in mice.

    Directory of Open Access Journals (Sweden)

    Guo Chen

    2011-09-01

    Full Text Available BACKGROUND: Schistosomiasis japonica is a zoonotic parasitic disease and oral vaccine delivery system would be benefit for prevention of this disease. Although attenuated salmonella has been used as an antigen expression vector for oral vaccine development, the membrane-bound vacuoles in which bacteria reside hinders the presentation of expressed heterologous antigens to the major histocompatibility complex (MHC molecules. The present work used an attenuated Salmonella typhimurium strain VNP20009 to secretory expression of Sj23LHDGST bivalent antigen from Schistosoma japonicum and tested the protective efficacy against S. japonicum infection in orally immunized mice. METHODOLOGY/PRINCIPAL FINDINGS: Promoters (nirB or pagC were used to express the antigen (Sj23LHDGST and the Salmonella type III or α-hemolysin secretion system was employed to secrete it. The immunoblotting analysis and fluorescent microscopy revealed that the antigen was effectively expressed and delivered to the cytosol of macrophages in vitro. Among recombinant vaccine strains, an engineered VNP20009 which expressed the antigen by nirB promoter and secreted it through type III secretion system (nirB-sopE(1-104-Sj23LHD-GST efficiently protected against S. japonicum infection in a mouse model. This strain elicited a predominantly IgG(2a antibody response and a markedly increase in the production of IL-12 and IFN-γ. The flow cytometric analysis demonstrated that this strain caused T cell activation as evidenced by significantly increased expression of CD44 and CD69. CONCLUSION/SIGNIFICANCE: Oral delivery of antigen by nirB-driven Salmonella typhimurium type III secretion system is a novel, safe, inexpensive, efficient and convenient approach for schistosome vaccine development.

  12. Protective immune mechanisms against pre-erythrocytic forms of Plasmodium berghei depend on the target antigen

    Directory of Open Access Journals (Sweden)

    Elke S. Bergmann-Leitner

    2014-01-01

    Full Text Available Pre-erythrocytic malaria vaccines are believed to either stop the injected sporozoites from reaching the liver or to direct cellular immune responses towards eliminating infected hepatocytes. The present study reveals for the first time the anatomical sites at which these immune mechanisms act against the malaria parasites. To determine the mechanisms leading to protection mediated by two previously characterized vaccines against either the circumsporozoite protein (CSP or the cell traversal protein for ookinetes and sporozoites (CelTOS, mice were immunized and subsequently challenged by subcutaneous injection of salivary gland sporozoites of luciferase-transgenic Plasmodium berghei parasites. The In Vivo Imaging System (IVIS was used to identify the anatomical site where the vaccine-induced immune response eliminates sporozoites after injection. The data demonstrate that CSP-based immunity acts at the site of infection (skin whereas CelTOS-based immunity is only partially efficient in the skin and allows reduced levels of liver infection that can be subsequently cleared. The results of this study challenge assumptions regarding CSP-mediated immune mechanisms and call into question the validity of some commonly used assays to evaluate anti-CSP immune responses. The knowledge of the mechanism and events leading to infection or immune defense will guide supportive treatment with drugs or combination therapies and thus accelerate the development of effective antimalarial strategies.

  13. Evaluating the A-Subunit of the Heat-Labile Toxin (LT As an Immunogen and a Protective Antigen Against Enterotoxigenic Escherichia coli (ETEC.

    Directory of Open Access Journals (Sweden)

    Elizabeth B Norton

    Full Text Available Diarrheal illness contributes to malnutrition, stunted growth, impaired cognitive development, and high morbidity rates in children worldwide. Enterotoxigenic Escherichia coli (ETEC is a major contributor to this diarrheal disease burden. ETEC cause disease in the small intestine by means of colonization factors and by production of a heat-labile enterotoxin (LT and/or a small non-immunogenic heat-stable enterotoxin (ST. Overall, the majority of ETEC produce both ST and LT. LT induces secretion via an enzymatically active A-subunit (LT-A and a pentameric, cell-binding B-subunit (LT-B. The importance of anti-LT antibodies has been demonstrated in multiple clinical and epidemiological studies, and a number of potential ETEC vaccine candidates have included LT-B as an important immunogen. However, there is limited information about the potential contribution of LT-A to development of protective immunity. In the current study, we evaluate the immune response against the A-subunit of LT as well as the A-subunit's potential as a protective antigen when administered alone or in combination with the B-subunit of LT. We evaluated human sera from individuals challenged with a prototypic wild-type ETEC strain as well as sera from individuals living in an ETEC endemic area for the presence of anti-LT, anti-LT-A and anti-LT-B antibodies. In both cases, a significant number of individuals intentionally or endemically infected with ETEC developed antibodies against both LT subunits. In addition, animals immunized with the recombinant proteins developed robust antibody responses that were able to neutralize the enterotoxic and cytotoxic effects of native LT by blocking binding and entry into cells (anti-LT-B or the intracellular enzymatic activity of the toxin (anti-LT-A. Moreover, antibodies to both LT subunits acted synergistically to neutralize the holotoxin when combined. Taken together, these data support the inclusion of both LT-A and LT-B in prospective

  14. Protective Antigen-Specific Memory B Cells Persist Years after Anthrax Vaccination and Correlate with Humoral Immunity

    Directory of Open Access Journals (Sweden)

    Lori Garman

    2014-08-01

    Full Text Available Anthrax Vaccine Adsorbed (AVA generates short-lived protective antigen (PA specific IgG that correlates with in vitro toxin neutralization and protection from Bacillus anthracis challenge. Animal studies suggest that when PA-specific IgG has waned, survival after spore challenge correlates with an activation of PA-specific memory B cells. Here, we characterize the quantity and the longevity of AVA-induced memory B cell responses in humans. Peripheral blood mononuclear cells (PBMCs from individuals vaccinated ≥3 times with AVA (n = 50 were collected early (3–6 months, n = 27 or late after their last vaccination (2–5 years, n = 23, pan-stimulated, and assayed by ELISPOT for total and PA-specific memory B cells differentiated into antibody secreting cells (ASCs. PA-specific ASC percentages ranged from 0.02% to 6.25% (median: 1.57% and did not differ between early and late post-vaccination individuals. PA-specific ASC percentages correlated with plasma PA-specific IgG (r = 0.42, p = 0.03 and toxin neutralization (r = 0.52, p = 0.003 early post vaccination. PA-specific ASC percentages correlated with supernatant anti-PA both early (r = 0.60, p = 0.001 and late post vaccination (r = 0.71, p < 0.0001. These data suggest PA-specific memory B cell responses are long-lived and can be estimated after recent vaccination by the magnitude and neutralization capacity of the humoral response.

  15. Immunogenicity and protective role of antigenic regions from five outer membrane proteins of Flavobacterium columnare in grass carp Ctenopharyngodon idella

    Science.gov (United States)

    Luo, Zhang; Liu, Zhixin; Fu, Jianping; Zhang, Qiusheng; Huang, Bei; Nie, Pin

    2016-11-01

    Flavobacterium columnare causes columnaris disease in freshwater fish. In the present study, the antigenic regions of five outer membrane proteins (OMPs), including zinc metalloprotease, prolyl oligopeptidase, thermolysin, collagenase and chondroitin AC lyase, were bioinformatically analyzed, fused together, and then expressed as a recombinant fusion protein in Escherichia coli. The expressed protein of 95.6 kDa, as estimated by 10% sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was consistent with the molecular weight deduced from the amino acid sequence. The purified recombinant protein was used to vaccinate the grass carp, Ctenopharyngodon idella. Following vaccination of the fish their IgM antibody levels were examined, as was the expression of IgM, IgD and IgZ immunoglobulin genes and other genes such as MHC Iα and MHC IIβ, which are also involved in adaptive immunity. Interleukin genes ( IL), including IL-1β, IL-8 and IL-10, and type I and type II interferon ( IFN) genes were also examined. At 3 and 4 weeks post-vaccination (wpv), significant increases in IgM antibody levels were observed in the fish vaccinated with the recombinant fusion protein, and an increase in the expression levels of IgM, IgD and IgZ genes was also detected following the vaccinations, thus indicating that an adaptive immune response was induced by the vaccinations. Early increases in the expression levels of IL and IFN genes were also observed in the vaccinated fish. At four wpv, the fish were challenged with F. columnare, and the vaccinated fish showed a good level of protection against this pathogen, with 39% relative percent survival (RPS) compared with the control group. It can be concluded, therefore, that the five OMPs, in the form of a recombinant fusion protein vaccine, induced an immune response in fish and protection against F. columnare.

  16. Employing Escherichia coli-derived outer membrane vesicles as an antigen delivery platform elicits protective immunity against Acinetobacter baumannii infection

    Science.gov (United States)

    Huang, Weiwei; Wang, Shijie; Yao, Yufeng; Xia, Ye; Yang, Xu; Li, Kui; Sun, Pengyan; Liu, Cunbao; Sun, Wenjia; Bai, Hongmei; Chu, Xiaojie; Li, Yang; Ma, Yanbing

    2016-11-01

    Outer membrane vesicles (OMVs) have proven to be highly immunogenic and induced an immune response against bacterial infection in human clinics and animal models. We sought to investigate whether engineered OMVs can be a feasible antigen-delivery platform for efficiently inducing specific antibody responses. In this study, Omp22 (an outer membrane protein of A. baumannii) was displayed on E. coli DH5α-derived OMVs (Omp22-OMVs) using recombinant gene technology. The morphological features of Omp22-OMVs were similar to those of wild-type OMVs (wtOMVs). Immunization with Omp22-OMVs induced high titers of Omp22-specific antibodies. In a murine sepsis model, Omp22-OMV immunization significantly protected mice from lethal challenge with a clinically isolated A. baumannii strain, which was evidenced by the increased survival rate of the mice, the reduced bacterial burdens in the lung, spleen, liver, kidney, and blood, and the suppressed serum levels of inflammatory cytokines. In vitro opsonophagocytosis assays showed that antiserum collected from Omp22-OMV-immunized mice had bactericidal activity against clinical isolates, which was partly specific antibody-dependent. These results strongly indicated that engineered OMVs could display a whole heterologous protein (~22 kDa) on the surface and effectively induce specific antibody responses, and thus OMVs have the potential to be a feasible vaccine platform.

  17. Effect of delayed anthrax vaccine dose on Bacillus anthracis protective antigen IgG response and lethal toxin neutralization activity.

    Science.gov (United States)

    Pittman, Phillip R; Fisher, Diana; Quinn, Xiaofei; Schmader, Trevor; Barrera-Oro, Julio G

    2013-10-17

    We describe the Bacillus anthracis protective antigen IgG antibody response and the B. anthracis lethal toxin neutralization activity to a delayed dose of anthrax vaccine adsorbed (AVA, BioThrax(®)) using validated assays. 373 individuals received 1, 2, or 3 priming doses, 18-24 months afterward, they received a delayed dose of AVA. Overall, 23.6% of subjects showed detectable anti-PA IgG before the boost, compared to 99.2% (P<0.0001) 28 days after the boost. Geometric mean anti-PA IgG concentration (GMC) was 1.66 μg/mL before and 887.82 μg/mL after the boost (P<0.0001). The proportion of individuals with four-fold increase in GMC following the boost ranged from 93.8% to 100%. Robust anti-PA IgG levels and B. anthracis lethal toxin neutralization activity are induced when an AVA dose is delayed as long as two years. These data support continuing with the vaccination schedule when a dose is delayed as long as two years rather than restarting the series.

  18. Specific, sensitive, and quantitative enzyme-linked immunosorbent assay for human immunoglobulin G antibodies to anthrax toxin protective antigen.

    Science.gov (United States)

    Quinn, Conrad P; Semenova, Vera A; Elie, Cheryl M; Romero-Steiner, Sandra; Greene, Carolyn; Li, Han; Stamey, Karen; Steward-Clark, Evelene; Schmidt, Daniel S; Mothershed, Elizabeth; Pruckler, Janet; Schwartz, Stephanie; Benson, Robert F; Helsel, Leta O; Holder, Patricia F; Johnson, Scott E; Kellum, Molly; Messmer, Trudy; Thacker, W Lanier; Besser, Lilah; Plikaytis, Brian D; Taylor, Thomas H; Freeman, Alison E; Wallace, Kelly J; Dull, Peter; Sejvar, Jim; Bruce, Erica; Moreno, Rosa; Schuchat, Anne; Lingappa, Jairam R; Martin, Sandra K; Walls, John; Bronsdon, Melinda; Carlone, George M; Bajani-Ari, Mary; Ashford, David A; Stephens, David S; Perkins, Bradley A

    2002-10-01

    The bioterrorism-associated human anthrax epidemic in the fall of 2001 highlighted the need for a sensitive, reproducible, and specific laboratory test for the confirmatory diagnosis of human anthrax. The Centers for Disease Control and Prevention developed, optimized, and rapidly qualified an enzyme-linked immunosorbent assay (ELISA) for immunoglobulin G (IgG) antibodies to Bacillus anthracis protective antigen (PA) in human serum. The qualified ELISA had a minimum detection limit of 0.06 micro g/mL, a reliable lower limit of detection of 0.09 micro g/mL, and a lower limit of quantification in undiluted serum specimens of 3.0 micro g/mL anti-PA IgG. The diagnostic sensitivity of the assay was 97.8%, and the diagnostic specificity was 97.6%. A competitive inhibition anti-PA IgG ELISA was also developed to enhance diagnostic specificity to 100%. The anti-PA ELISAs proved valuable for the confirmation of cases of cutaneous and inhalational anthrax and evaluation of patients in whom the diagnosis of anthrax was being considered.

  19. A CpG-Ficoll Nanoparticle Adjuvant for Anthrax Protective Antigen Enhances Immunogenicity and Provides Single-Immunization Protection against Inhaled Anthrax in Monkeys.

    Science.gov (United States)

    Kachura, Melissa A; Hickle, Colin; Kell, Sariah A; Sathe, Atul; Calacsan, Carlo; Kiwan, Radwan; Hall, Brian; Milley, Robert; Ott, Gary; Coffman, Robert L; Kanzler, Holger; Campbell, John D

    2016-01-01

    Nanoparticulate delivery systems for vaccine adjuvants, designed to enhance targeting of secondary lymphoid organs and activation of APCs, have shown substantial promise for enhanced immunopotentiation. We investigated the adjuvant activity of synthetic oligonucleotides containing CpG-rich motifs linked to the sucrose polymer Ficoll, forming soluble 50-nm particles (DV230-Ficoll), each containing >100 molecules of the TLR9 ligand, DV230. DV230-Ficoll was evaluated as an adjuvant for a candidate vaccine for anthrax using recombinant protective Ag (rPA) from Bacillus anthracis. A single immunization with rPA plus DV230-Ficoll induced 10-fold higher titers of toxin-neutralizing Abs in cynomolgus monkeys at 2 wk compared with animals immunized with equivalent amounts of monomeric DV230. Monkeys immunized either once or twice with rPA plus DV230-Ficoll were completely protected from challenge with 200 LD50 aerosolized anthrax spores. In mice, DV230-Ficoll was more potent than DV230 for the induction of innate immune responses at the injection site and draining lymph nodes. DV230-Ficoll was preferentially colocalized with rPA in key APC populations and induced greater maturation marker expression (CD69 and CD86) on these cells and stronger germinal center B and T cell responses, relative to DV230. DV230-Ficoll was also preferentially retained at the injection site and draining lymph nodes and produced fewer systemic inflammatory responses. These findings support the development of DV230-Ficoll as an adjuvant platform, particularly for vaccines such as for anthrax, for which rapid induction of protective immunity and memory with a single injection is very important.

  20. Generation of a safe Salmonella Gallinarum vaccine candidate that secretes an adjuvant protein with immunogenicity and protective efficacy against fowl typhoid.

    Science.gov (United States)

    Nandre, R M; Lee, J H

    2014-01-01

    We constructed a live, attenuated Salmonella Gallinarum (SG) that secretes heat-labile enterotoxin B subunit protein (LTB), and evaluated this strain as a new vaccine candidate by assessing its safety, immunogenicity and protective efficacy against fowl typhoid. An asd(+) p15A ori low-copy plasmid containing eltB encoding LTB was transformed into a ΔlonΔcpxRΔasd SG (JOL967) to construct the candidate, JOL1355. In Experiments 1 and 2, birds were orally immunized with JOL1355 at 4 weeks of age, while control birds were inoculated with sterile phosphate-buffered saline. In Experiment 2, the birds of both groups were orally challenged with a virulent SG at 8 weeks of age. In Experiment 1, examination for safety revealed that the immunized group did not show any bacterial counts of the vaccine candidate in the liver and spleen. Birds immunized with the vaccine candidate showed a significant increase in systemic IgG and mucosal secretory IgA levels in Experiment 2. In addition, the lymphocyte proliferation response and the numbers of CD3(+)CD4(+) and CD3(+)CD8(+) T cells were also significantly elevated in the immunized group, which indicated that the candidate also induced cellular immune responses. In the protection assay, efficient protection with only 16% mortality in the immunized group was observed against challenge compared with 76% mortality in the control group. These results indicate that the live, attenuated SG secreting LTB can be a safe vaccine candidate. In addition, it can induce humoral and cellular immune responses and can efficiently reduce mortality of birds exposed to fowl typhoid.

  1. Recombinant measles AIK-C vaccine strain expressing heterologous virus antigens.

    Science.gov (United States)

    Nakayama, Tetsuo; Sawada, Akihito; Yamaji, Yoshiaki; Ito, Takashi

    2016-01-04

    Further attenuated measles vaccines were developed more than 50 years ago and have been used throughout the world. Recombinant measles vaccine candidates have been developed and express several heterologous virus protective antigens. Immunogenicity and protective actions were confirmed using experimental animals: transgenic mice, cotton rats, and primates. The recent development of measles vaccine-based vectored vaccine candidates has been reviewed and some information on recombinant measles vaccines expressing respiratory syncytial virus proteins has been shown and discussed.

  2. Age-dependent association between IgG2 and IgG3 subclasses to Pf332-C231 antigen and protection from malaria, and induction of protective antibodies by sub-patent malaria infections, in Daraweesh

    DEFF Research Database (Denmark)

    Giha, Hayder A; Nasr, Amre; Iriemenam, Nnaemeka C;

    2010-01-01

    , three variable markers for protection were emerged, two age-dependent, the antibody response to Pf332-C231 and an unidentified marker (likely immune response to other antigens), and the third was an age-independent unidentified marker (possibly gene polymorphisms). In conclusion, this report suggests.......211, p=0.014, respectively), and also with age (CC - 0.311, p

  3. Phase 1/2a Study of the Malaria Vaccine Candidate Apical Membrane Antigen-1 (AMA-1) Administered in Adjuvant System AS01B or AS02A

    Science.gov (United States)

    2009-04-01

    International Conference on Harmonisation (ICH) guidelines and confirmed the vaccine antigen was stable and potent from date of manufacture through...Maryland, United States of America, 8 Malaria Vaccine Development Program, United States Agency for International Development, Washington D. C., United...into a multi-stage, multi-component vaccine [22]. First, an AMA-1 vaccine must confer significant clinical benefit in either a Phase 2a malaria

  4. Protection from anti-TCR/CD3-induced apoptosis in immature thymocytes by a signal through thymic shared antigen-1/stem cell antigen-2.

    Science.gov (United States)

    Noda, S; Kosugi, A; Saitoh, S; Narumiya, S; Hamaoka, T

    1996-05-01

    During T cell development in the thymus, the expression of thymic shared antigen-1 (TSA-1)/stem cell antigen-2 (Sca-2), a glycosylphosphatidylinositol (GPI)-anchored differentiation antigen, is developmentally regulated. The expression level of TSA-1 is the highest in most immature CD4- CD8- thymocytes, high in CD4+ CD8+ thymocytes, but barely detectable in mature CD4+ CD8- or CD4- CD8- thymocytes and peripheral T cells. We have previously shown that surface TSA-1 expression in peripheral T cells is induced upon activation and that anti-TSA-1 mAb inhibits the T cell receptor (TCR) signaling pathway in activated T cells. In the present study, we have analyzed a role of TSA-1 in thymic selection events, especially in TCR-mediated apoptosis. In in vitro experiments, anti-TSA-1 blocked anti-CD3-induced cell death of T cell hybridomas. When anti-TSA-1 was injected into newborn mice in vivo together with anti-CD3 epsilon or anti-TCR-beta, TCR/CD3-mediated apoptosis of thymocytes was almost completely blocked. The blockade of apoptosis was defined by the inhibition of, first, the decrease in total number of thymocytes; second, the decrease in percentages of CD4+ CD8+ thymocytes; and third, the induction of DNA fragmentation. However, anti-TSA-1 did not block either steroid- or radiation-induced apoptosis, indicating that a signal via TSA-1 does not inhibit a common pathway of thymocyte apoptosis. Since TCR-mediated apoptosis is pivotal in thymic ontogeny, these results suggest that TSA-1/Sca-2 is an important cell surface molecule regulating the fate of a developing T cell.

  5. [Characterization of surface antigens of the nematode parasite Trichinella spiralis: study of its role in protection mechanisms and their usefulness in the diagnosis of trichinosis].

    Science.gov (United States)

    Ortega-Pierres, M G

    1995-01-01

    Among the most important aspects in the study of trichinosis are the development of specific and sensitive diagnostic methods for the detection of the infection by the parasite as well as the characterization of antigens from Trichinella spiralis that induce protection in the host. In the context, the characterization of surface stichosome and excretory secretory antigens of T. spiralis muscle larvae has been an important issue due to the high immunogenicity of such components in most hosts so far studied. In this work, we have been able to identify and characterize molecules from both compartments of muscle larvae. These components have been used in assays for specific detection of T. spiralis infections particularly in pigs, as well as in assays to evaluate their role in the induction of protection in mice.

  6. Detection of anthrax protective antigen (PA) using europium labeled anti-PA monoclonal antibody and time-resolved fluorescence.

    Science.gov (United States)

    Stoddard, Robyn A; Quinn, Conrad P; Schiffer, Jarad M; Boyer, Anne E; Goldstein, Jason; Bagarozzi, Dennis A; Soroka, Stephen D; Dauphin, Leslie A; Hoffmaster, Alex R

    2014-06-01

    Inhalation anthrax is a rare but acute infectious disease following adsorption of Bacillus anthracis spores through the lungs. The disease has a high fatality rate if untreated, but early and correct diagnosis has a significant impact on case patient recovery. The early symptoms of inhalation anthrax are, however, non-specific and current anthrax diagnostics are primarily dependent upon culture and confirmatory real-time PCR. Consequently, there may be a significant delay in diagnosis and targeted treatment. Rapid, culture-independent diagnostic tests are therefore needed, particularly in the context of a large scale emergency response. The aim of this study was to evaluate the ability of monoclonal antibodies to detect anthrax toxin proteins that are secreted early in the course of B. anthracis infection using a time-resolved fluorescence (TRF) immunoassay. We selected monoclonal antibodies that could detect protective antigen (PA), as PA83 and also PA63 and LF in the lethal toxin complex. The assay reliable detection limit (RDL) was 6.63×10(-6)μM (0.551ng/ml) for PA83 and 2.51×10(-5)μM (1.58ng/ml) for PA63. Despite variable precision and accuracy of the assay, PA was detected in 9 out of 10 sera samples from anthrax confirmed case patients with cutaneous (n=7), inhalation (n=2), and gastrointestinal (n=1) disease. Anthrax Immune Globulin (AIG), which has been used in treatment of clinical anthrax, interfered with detection of PA. This study demonstrates a culture-independent method of diagnosing anthrax through the use of monoclonal antibodies to detect PA and LF in the lethal toxin complex.

  7. Affinity binding of antibodies to supermacroporous cryogel adsorbents with immobilized protein A for removal of anthrax toxin protective antigen.

    Science.gov (United States)

    Ingavle, Ganesh C; Baillie, Les W J; Zheng, Yishan; Lis, Elzbieta K; Savina, Irina N; Howell, Carol A; Mikhalovsky, Sergey V; Sandeman, Susan R

    2015-05-01

    Polymeric cryogels are efficient carriers for the immobilization of biomolecules because of their unique macroporous structure, permeability, mechanical stability and different surface chemical functionalities. The aim of the study was to demonstrate the potential use of macroporous monolithic cryogels for biotoxin removal using anthrax toxin protective antigen (PA), the central cell-binding component of the anthrax exotoxins, and covalent immobilization of monoclonal antibodies. The affinity ligand (protein A) was chemically coupled to the reactive hydroxyl and epoxy-derivatized monolithic cryogels and the binding efficiencies of protein A, monoclonal antibodies to the cryogel column were determined. Our results show differences in the binding capacity of protein A as well as monoclonal antibodies to the cryogel adsorbents caused by ligand concentrations, physical properties and morphology of surface matrices. The cytotoxicity potential of the cryogels was determined by an in vitro viability assay using V79 lung fibroblast as a model cell and the results reveal that the cryogels are non-cytotoxic. Finally, the adsorptive capacities of PA from phosphate buffered saline (PBS) were evaluated towards a non-glycosylated, plant-derived human monoclonal antibody (PANG) and a glycosylated human monoclonal antibody (Valortim(®)), both of which were covalently attached via protein A immobilization. Optimal binding capacities of 108 and 117 mg/g of antibody to the adsorbent were observed for PANG attached poly(acrylamide-allyl glycidyl ether) [poly(AAm-AGE)] and Valortim(®) attached poly(AAm-AGE) cryogels, respectively, This indicated that glycosylation status of Valortim(®) antibody could significantly increase (8%) its binding capacity relative to the PANG antibody on poly(AAm-AGE)-protien-A column (p PBS through PANG or Valortim bound poly(AAm-AGE) cryogel were significantly (p PBS over 60 min of circulation. The high adsorption capacity towards anthrax toxin PA of the

  8. O-mannosylation of the Mycobacterium tuberculosis adhesin Apa is crucial for T cell antigenicity during infection but is expendable for protection.

    Science.gov (United States)

    Nandakumar, Subhadra; Kannanganat, Sunil; Dobos, Karen M; Lucas, Megan; Spencer, John S; Fang, Sunan; McDonald, Melissa A; Pohl, Jan; Birkness, Kristin; Chamcha, Venkateswarlu; Ramirez, Melissa V; Plikaytis, Bonnie B; Posey, James E; Amara, Rama Rao; Sable, Suraj B

    2013-01-01

    Glycosylation is the most abundant post-translational polypeptide chain modification in nature. Although carbohydrate modification of protein antigens from many microbial pathogens constitutes important components of B cell epitopes, the role in T cell immunity is not completely understood. Here, using ELISPOT and polychromatic flow cytometry, we show that O-mannosylation of the adhesin, Apa, of Mycobacterium tuberculosis (Mtb) is crucial for its T cell antigenicity in humans and mice after infection. However, subunit vaccination with both mannosylated and non-mannosylated Apa induced a comparable magnitude and quality of T cell response and imparted similar levels of protection against Mtb challenge in mice. Both forms equally improved waning BCG vaccine-induced protection in elderly mice after subunit boosting. Thus, O-mannosylation of Apa is required for antigenicity but appears to be dispensable for its immunogenicity and protective efficacy in mice. These results have implications for the development of subunit vaccines using post-translationally modified proteins such as glycoproteins against infectious diseases like tuberculosis.

  9. Immunochemical analysis of Taenia taeniaeformis antigens expressed in Escherichia coli.

    Science.gov (United States)

    Bowtell, D D; Saint, R B; Rickard, M D; Mitchell, G F

    1986-12-01

    Previously we reported the isolation of several Escherichia coli clones expressing fragments of Taenia taeniaeformis antigens as beta-galactosidase fused proteins (Bowtell, Saint, Rickard & Mitchell, 1984). Here we describe the isolation of additional antigen-expressing clones from a larval cDNA library and the assignment of these clones to 7 antigen families. These were isolated with a polyspecific rabbit antiserum raised to the oncosphere. Since this serum was capable of reacting with a large number of antigens, it was important to develop techniques for rapidly determining the identity of the native T. taeniaeformis molecule corresponding to a cloned antigen gene. These included active immunization of rabbits with fused proteins and several techniques involving affinity purification on immobilized fused proteins. The reactivity of the antigen-positive clones with sera from humans infected with related parasites was also assessed. Finally, immunization of mice with several fused proteins failed to protect against subsequent infection, although antigens previously identified as candidate host-protective antigens (Bowtell, Mitchell, Anders, Lightowlers & Rickard, 1983) have yet to be identified in the expression library.

  10. Intranasal Immunization with the Cholera Toxin B Subunit-Pneumococcal Surface Antigen A Fusion Protein Induces Protection against Colonization with Streptococcus pneumoniae and Has Negligible Impact on the Nasopharyngeal and Oral Microbiota of Mice

    OpenAIRE

    F.C. Pimenta; Miyaji, E. N.; Arêas, A. P. M.; Oliveira, M. L. S.; de Andrade, A. L. S. S.; Ho, P.L.; Hollingshead, S. K.; Leite, L. C. C.

    2006-01-01

    One of the candidate proteins for a mucosal vaccine antigen against Streptococcus pneumoniae is PsaA (pneumococcal surface antigen A). Vaccines targeting mucosal immunity may raise concerns as to possible alterations in the normal microbiota, especially in the case of PsaA, which was shown to have homologs with elevated sequence identity in other viridans group streptococci. In this work, we demonstrate that intranasal immunization with a cholera toxin B subunit-PsaA fusion protein is able to...

  11. Protection of mice against Staphylococcus aureus infection by a recombinant protein ClfA-IsdB-Hlg as a vaccine candidate.

    Science.gov (United States)

    Delfani, Somayeh; Mohabati Mobarez, Ashraf; Imani Fooladi, Abbas Ali; Amani, Jafar; Emaneini, Mohammad

    2016-02-01

    Staphylococcus aureus is one of the most important causes of nosocomial infections. An effective vaccine to prevent S. aureus infections is urgently required due to the dramatic increase in the number of antibiotic-resistant strains. In this report, we evaluated a newly recombinant protein composed of selected antigenic regions of clumping factor A (ClfA), iron surface determinant B (IsdB) and gamma hemolysin B (HlgB) of S. aureus and sequence coding for hydrophobic linkers between three domains. The recombinant gene was constructed in pET-28a (+) and expressed in Escherichia coli BL21. In addition, sequence coding for a His(6)-tag was added followed by a hybrid procedure of nickel chelate protein purification. Immunization of BALB/c mice with the recombinant protein ClfA-IsdB-Hlg evoked antigen-specific antibodies that could opsonize S. aureus cells, enhancing in vitro phagocytosis by macrophages. Vaccination with the recombinant protein also reduced the bacterial load recovered from mice spleen samples and increased survival following the intraperitoneal challenge with pathogenic S. aureus compared to the control mice. Our results showed that the recombinant protein ClfA-IsdB-Hlg is a promising vaccine candidate for the prevention of S. aureus bacteremia infections.

  12. Protective immunity induced in mice by F8.1 and F8.2 antigens purified from Schistosoma mansoni eggs

    Directory of Open Access Journals (Sweden)

    Claudia Campra Ferreira

    1998-01-01

    Full Text Available Schistosoma mansoni soluble egg antigens (SEA were fractionated by isoelectric focusing, resulting in 20 components, characterized by pH, absorbance and protein concentration. The higher absorbance fractions were submitted to electrophoresis, and fraction 8 (F8 presented a specific pattern of bands on its isoelectric point. Protein 3 was observed only on F8, and so, it was utilized to rabbit immunization, in order to evaluate its capacity of inducing protective immunity. IgG antibodies from rabbit anti-F8 serum were coupled to Sepharose, and used to obtain the specific antigen by affinity chromatography. This antigen, submitted to electrophoresis, presented two proteic bands (F8.1 and F8.2, which were transferred to nitrocellulose membrane (PVDF and sequenciated. The homology of F8.2 to known proteins was determined using the Basic Local Alignment Search Tool program (BLASTp. Significant homologies were obtained for the rabbit cytosolic Ca2+ uptake inhibitor, and for the bird a1-proteinase inhibitor. Immunization of mice with F8.1 and F8.2, in the presence of Corynebacterium parvum and Al(OH3 as adjuvant, induced a significant protection degree against challenge infection, as observed by the decrease on worm burden recovered from portal system.

  13. Further characterization of protective Trypanosoma cruzi-specific CD4+ T-cell clones: T helper type 1-like phenotype and reactivity with shed trypomastigote antigens.

    Science.gov (United States)

    Nickell, S P; Keane, M; So, M

    1993-01-01

    We previously reported the isolation from immune mice of a panel of murine clonal T-cell lines which specifically recognize antigens expressed by the trypomastigote stage of the protozoan parasite Trypanosoma cruzi, the causative agent of human Chagas' disease. Our analysis indicated that distinct clones which recognize common as well as strain-specific antigenic determinants were represented. The immunoprotective potential of several of these T-cell clones was demonstrated by adoptive transfer of protection to naive syngeneic recipients. Here we report that these T-cell clones are all of the TH1 phenotype, as determined from their lymphokine secretion patterns. Significant levels of stimulatory activity for each clone were detected in trypomastigote supernatants, and the release of this activity was time and temperature dependent. Seven of 10 T-cell clones tested responded to nitrocellulose-immunoblotted trypomastigote proteins in the range of 90 to 47 kDa; no fewer than six distinct epitopes residing on at least five distinct polypeptide species were recognized by this panel of clones. Two clones (2G8 and 4B10) previously shown to protect in vivo responded to immunoblotted proteins in the range of 65 to 53 and 90 to 80 kD, respectively. Stimulatory activity for the latter clone was shown to be expressed on the surface of trypomastigotes and to bind specifically to wheat germ agglutinin, indicating that its target antigen is an 85-kDa trypomastigote surface glycoprotein. PMID:8335358

  14. An adjuvanted, tetravalent dengue virus purified inactivated vaccine candidate induces long-lasting and protective antibody responses against dengue challenge in rhesus macaques.

    Science.gov (United States)

    Fernandez, Stefan; Thomas, Stephen J; De La Barrera, Rafael; Im-Erbsin, Rawiwan; Jarman, Richard G; Baras, Benoît; Toussaint, Jean-François; Mossman, Sally; Innis, Bruce L; Schmidt, Alexander; Malice, Marie-Pierre; Festraets, Pascale; Warter, Lucile; Putnak, J Robert; Eckels, Kenneth H

    2015-04-01

    The immunogenicity and protective efficacy of a candidate tetravalent dengue virus purified inactivated vaccine (TDENV PIV) formulated with alum or an Adjuvant System (AS01, AS03 tested at three different dose levels, or AS04) was evaluated in a 0, 1-month vaccination schedule in rhesus macaques. One month after dose 2, all adjuvanted formulations elicited robust and persisting neutralizing antibody titers against all four dengue virus serotypes. Most of the formulations tested prevented viremia after challenge, with the dengue serotype 1 and 2 virus strains administered at 40 and 32 weeks post-dose 2, respectively. This study shows that inactivated dengue vaccines, when formulated with alum or an Adjuvant System, are candidates for further development.

  15. [IgG responses to candidate malaria vaccine antigens in the urban area of Dakar (Senegal): evolution according to age and parasitemia in patients with mild symptoms].

    Science.gov (United States)

    Mbengue, B; Sylla Niang, M; Ndiaye Diallo, R; Diop, G; Thiam, A; Ka, O; Touré, A; Tall, A; Perraut, R; Dièye, A

    2015-03-01

    Malaria remains a major problem in African countries despite substantial decreases in morbidity and mortality due to sustained control programs. Studies for the evaluation of qualitative or quantitative Ab responses to key targets of anti-plasmodium immunity were mostly done in rural endemic setting compared to urban area. In a cohort of 200 patients with mild malaria and living in Dakar, we analyze total and subclasses IgG responses to a panel of P. falciparum blood stage antigens: MSP1p19, MSP3, EB200, GST-5 and R23. A mean age of 15 yrs (4 to 56 yrs) and parasitemia between 0.1 to 17% were found. Levels of IgG anti-MSP3 were higher in patients with low parasitemia (≤1%) and appear negatively correlated to parasite densities (Rho =. 0.54; p= 0.021). This correlation is more significant in children (≤ 15 yrs). In addition, an increase of IgG responses against MSP1p19 is highly observed in adults having a parasitemia less than 1%. In those patients, we find that IgG1 subclasses were predominant (p <0.01). Our study shows an association between Ab responses and parasitemia. This association is dependant to IgG anti-MSP3 in children and IgG anti-MSP1p19 in adults living in urban area.

  16. Protection of mice against Japanese encephalitis virus group II strain infections by combinations of monoclonal antibodies to different antigenic domains on glycoprotein E

    Directory of Open Access Journals (Sweden)

    Ashok Kumar Gupta

    2012-01-01

    Full Text Available A combination of at least three hemagglutination- inhibition-positive (HAI and virus-specific (Hs monoclonal antibodies (MAbs to glycoprotein E (gpE of Japanese encephalitis virus (JEV fully protected (100% mice against JEV strain 733913 infections (group 1. However, these representative epitopes are reported to have been lost on JEV group II strains. In the present study, therefore, the protective effect of various combinations of anti-gpE MAbs representing antigenic epitopes other than Hs was studied on mice infections with JEV group II strains: JEV strains 641686 and 691004. MAbs used in the protective experiments were characterized as HAI-negative virus-specific (NHs and HAI-positive flavivirus cross-reactive (Hx. Additionally, one of the Hs MAbs (MAb Hs-3 was included in the experiments. Mice were first administered single MAbs or their combinations intraperitoneally and 24 h later, infected with the virus intracerebrally. Protection rates of 70-75% were obtained with a combination of four MAbs: MAbs NHs-1, Hx-1, Hx-3 and Hs-3. However, protection rates of only 20-40% were obtained with three MAbs but none was observed with single or two MAbs. There was, however, a substantial increase in mice survival. The protective effect of several combinations of anti-gpE MAbs representing different antigenic epitopes might be due to the enhancement of binding within the same group and also between different MAb groups. The present results indicate that NHs and Hx epitopes should be incorporated with three Hs epitopes in a JEV vaccine that would have an added advantage, particularly in the flaviviral endemic areas with JEV strain variations.

  17. Vaccination with M2e-based multiple antigenic peptides: characterization of the B cell response and protection efficacy in inbred and outbred mice.

    Directory of Open Access Journals (Sweden)

    Amaya I Wolf

    Full Text Available BACKGROUND: The extracellular domain of the influenza A virus protein matrix protein 2 (M2e is remarkably conserved between various human isolates and thus is a viable target antigen for a universal influenza vaccine. With the goal of inducing protection in multiple mouse haplotypes, M2e-based multiple antigenic peptides (M2e-MAP were synthesized to contain promiscuous T helper determinants from the Plasmodium falciparum circumsporozoite protein, the hepatitis B virus antigen and the influenza virus hemagglutinin. Here, we investigated the nature of the M2e-MAP-induced B cell response in terms of the distribution of antibody (Ab secreting cells (ASCs and Ab isotypes, and tested the protective efficacy in various mouse strains. METHODOLOGY/PRINCIPAL FINDINGS: Immunization of BALB/c mice with M2e-MAPs together with potent adjuvants, CpG 1826 oligonucleotides (ODN and cholera toxin (CT elicited high M2e-specific serum Ab titers that protected mice against viral challenge. Subcutaneous (s.c. and intranasal (i.n. delivery of M2e-MAPs resulted in the induction of IgG in serum and airway secretions, however only i.n. immunization induced anti-M2e IgA ASCs locally in the lungs, correlating with M2-specific IgA in the bronchio-alveolar lavage (BAL. Interestingly, both routes of vaccination resulted in equal protection against viral challenge. Moreover, M2e-MAPs induced cross-reactive and protective responses to diverse M2e peptides and variant influenza viruses. However, in contrast to BALB/c mice, immunization of other inbred and outbred mouse strains did not induce protective Abs. This correlated with a defect in T cell but not B cell responsiveness to the M2e-MAPs. CONCLUSION/SIGNIFICANCE: Anti-M2e Abs induced by M2e-MAPs are highly cross-reactive and can mediate protection to variant viruses. Although synthetic MAPs are promising designs for vaccines, future constructs will need to be optimized for use in the genetically heterogeneous human

  18. The effect of different adjuvants on immune parameters and protection following vaccination of sheep with a larval-specific antigen of the gastrointestinal nematode, Haemonchus contortus.

    Directory of Open Access Journals (Sweden)

    David Piedrafita

    Full Text Available It has recently been recognised that vaccine adjuvants play a critical role in directing the nature of a vaccine induced effector response. In the present study, several adjuvants were evaluated for their ability to protect sheep after field vaccination with the larval-specific Haemonchus contortus antigen, HcsL3. Using a suboptimal antigen dose, aluminium adjuvant was shown to reduce the cumulative faecal egg counts (cFEC and worm burden by 23% and 25% respectively, in agreement with a previous study. The addition of Quil A to the aluminium-adjuvanted vaccine brought cFEC back to control levels. Vaccination with the adjuvant DEAE-dextran almost doubled the protection compared to the aluminium-adjuvanted vaccine resulting in 40% and 41% reduction in cFEC and worm counts compared to controls. Examination of skin responses following i.d. injection of exsheathed L3, revealed that cFEC was negatively correlated with wheal size and tissue eosinophils for the DEAE-dextran and aluminium-adjuvanted groups respectively. These studies have for the first time shown the potential of DEAE-dextran adjuvant for helminth vaccines, and discovered significant cellular correlates of vaccine-induced protection.

  19. Cross-reactivity of anthrax and C2 toxin: protective antigen promotes the uptake of botulinum C2I toxin into human endothelial cells.

    Directory of Open Access Journals (Sweden)

    Angelika Kronhardt

    Full Text Available Binary toxins are among the most potent bacterial protein toxins performing a cooperative mode of translocation and exhibit fatal enzymatic activities in eukaryotic cells. Anthrax and C2 toxin are the most prominent examples for the AB(7/8 type of toxins. The B subunits bind both host cell receptors and the enzymatic A polypeptides to trigger their internalization and translocation into the host cell cytosol. C2 toxin is composed of an actin ADP-ribosyltransferase (C2I and C2II binding subunits. Anthrax toxin is composed of adenylate cyclase (EF and MAPKK protease (LF enzymatic components associated to protective antigen (PA binding subunit. The binding and translocation components anthrax protective antigen (PA(63 and C2II of C2 toxin share a sequence homology of about 35%, suggesting that they might substitute for each other. Here we show by conducting in vitro measurements that PA(63 binds C2I and that C2II can bind both EF and LF. Anthrax edema factor (EF and lethal factor (LF have higher affinities to bind to channels formed by C2II than C2 toxin's C2I binds to anthrax protective antigen (PA(63. Furthermore, we could demonstrate that PA in high concentration has the ability to transport the enzymatic moiety C2I into target cells, causing actin modification and cell rounding. In contrast, C2II does not show significant capacity to promote cell intoxication by EF and LF. Together, our data unveiled the remarkable flexibility of PA in promoting C2I heterologous polypeptide translocation into cells.

  20. Phase 1/2a study of the malaria vaccine candidate apical membrane antigen-1 (AMA-1 administered in adjuvant system AS01B or AS02A.

    Directory of Open Access Journals (Sweden)

    Michele D Spring

    Full Text Available BACKGROUND: This Phase 1/2a study evaluated the safety, immunogenicity, and efficacy of an experimental malaria vaccine comprised of the recombinant Plasmodium falciparum protein apical membrane antigen-1 (AMA-1 representing the 3D7 allele formulated with either the AS01B or AS02A Adjuvant Systems. METHODOLOGY/PRINCIPAL FINDINGS: After a preliminary safety evaluation of low dose AMA-1/AS01B (10 microg/0.5 mL in 5 adults, 30 malaria-naïve adults were randomly allocated to receive full dose (50 microg/0.5 mL of AMA-1/AS01B (n = 15 or AMA-1/AS02A (n = 15, followed by a malaria challenge. All vaccinations were administered intramuscularly on a 0-, 1-, 2-month schedule. All volunteers experienced transient injection site erythema, swelling and pain. Two weeks post-third vaccination, anti-AMA-1 Geometric Mean Antibody Concentrations (GMCs with 95% Confidence Intervals (CIs were high: low dose AMA-1/AS01B 196 microg/mL (103-371 microg/mL, full dose AMA-1/AS01B 279 microg/mL (210-369 microg/mL and full dose AMA-1/AS02A 216 microg/mL (169-276 microg/mL with no significant difference among the 3 groups. The three vaccine formulations elicited equivalent functional antibody responses, as measured by growth inhibition assay (GIA, against homologous but not against heterologous (FVO parasites as well as demonstrable interferon-gamma (IFN-gamma responses. To assess efficacy, volunteers were challenged with P. falciparum-infected mosquitoes, and all became parasitemic, with no significant difference in the prepatent period by either light microscopy or quantitative polymerase chain reaction (qPCR. However, a small but significant reduction of parasitemia in the AMA-1/AS02A group was seen with a statistical model employing qPCR measurements. SIGNIFICANCE: All three vaccine formulations were found to be safe and highly immunogenic. These immune responses did not translate into significant vaccine efficacy in malaria-naïve adults employing a primary sporozoite

  1. Protective effects of a Modified Vaccinia Ankara-based vaccine candidate against Crimean-Congo Haemorrhagic Fever virus require both cellular and humoral responses.

    Directory of Open Access Journals (Sweden)

    Stuart D Dowall

    Full Text Available Crimean-Congo Haemorrhagic Fever (CCHF is a severe tick-borne disease, endemic in many countries in Africa, the Middle East, Eastern Europe and Asia. There is no approved vaccine currently available against CCHF. The most promising candidate, which has previously been shown to confer protection in the small animal model, is a modified Vaccinia Ankara virus vector expressing the CCHF viral glycoprotein (MVA-GP. It has been shown that MVA-GP induces both humoral and cellular immunogenicity. In the present study, sera and T-lymphocytes were passively and adoptively transferred into recipient mice prior to challenge with CCHF virus. Results demonstrated that mediators from both arms of the immune system were required to demonstrate protective effects against lethal challenge.

  2. Protective effects of a Modified Vaccinia Ankara-based vaccine candidate against Crimean-Congo Haemorrhagic Fever virus require both cellular and humoral responses.

    Science.gov (United States)

    Dowall, Stuart D; Graham, Victoria A; Rayner, Emma; Hunter, Laura; Watson, Robert; Taylor, Irene; Rule, Antony; Carroll, Miles W; Hewson, Roger

    2016-01-01

    Crimean-Congo Haemorrhagic Fever (CCHF) is a severe tick-borne disease, endemic in many countries in Africa, the Middle East, Eastern Europe and Asia. There is no approved vaccine currently available against CCHF. The most promising candidate, which has previously been shown to confer protection in the small animal model, is a modified Vaccinia Ankara virus vector expressing the CCHF viral glycoprotein (MVA-GP). It has been shown that MVA-GP induces both humoral and cellular immunogenicity. In the present study, sera and T-lymphocytes were passively and adoptively transferred into recipient mice prior to challenge with CCHF virus. Results demonstrated that mediators from both arms of the immune system were required to demonstrate protective effects against lethal challenge.

  3. Effect of wild-type Shigella species and attenuated Shigella vaccine candidates on small intestinal barrier function, antigen trafficking, and cytokine release.

    Science.gov (United States)

    Fiorentino, Maria; Levine, Myron M; Sztein, Marcelo B; Fasano, Alessio

    2014-01-01

    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 from the small to

  4. 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

  5. Candidate immunogenic membrane antigens of human pancreatic cancer%人胰腺癌相关免疫原性候选膜抗原的鉴定和验证

    Institute of Scientific and Technical Information of China (English)

    王维斌; 赵玉沛; 廖泉; 张太平; 吴文铭; 吴元德

    2010-01-01

    Objective To verify the obtained immunogenic membrane antigens candidate of pancreatic cancer in the performed research. Methods Pancreatic caner cell line SW1990 membrane protein underwent immunoblot with serum IgG purified from clinically collected sera of 66 pancreatic cancer patients. Number 3 and number 8 positive dots of immunoblot were identified by MALDI-TOF mass spectrometry and peptide mass frigerfrint matching. The candidate membrane antigens were further validated in cell lines by RT-PCR, real-time PCR and Western blot, and their different expression level of gene and protein in pancreatic caner cell lines were contrastly studied. Results Number 3 and number 8 positive dots were identified as: voltage-dependent anion channel ( VDAC3 ) and catechol-o-methyltransferase (COMT).RT-PCR,real-time PCR and Western blot showed that gene and protein of VDAC3 and COMT were expressed in the pancreatic cancer cell line SW1990, AsPc and P3 respectively. Conclusion VDAC3 and COMT might be the candidate immunogenic membrane antigens of human pancreatic cancer, and their gene and protein are differently expressed in the pancreatic cancer cell line SW1990,AsPc and P3.%目的 对前期蛋白质组学筛查、鉴定的胰腺癌相关免疫原性候选膜抗原进行验证.方法 应用基质辅助激光解吸离子化飞行时间质谱分析与肽质指纹库对前期从66例胰腺癌患者血清的IgG与人胰腺癌细胞株SW1990的膜蛋白免疫印迹杂交的3号和8号阳性点进行鉴定.再应用RT-PCR、real-time PCR和Western blot方法,在细胞株层面从基因及蛋白水平对筛查出的膜抗原进行有效性验证,并比较不同胰腺癌细胞株中目的膜抗原的基因及蛋白表达水平的差异.结果 3号和8号阳性点经质谱分析鉴定分别为电压依赖性离子通道3(VDAC3)和儿茶酚胺氧位甲基转移酶(COMT).经RT-PCR、real-time PCR和Western blot实验证明,候选膜抗原VDAC3和COMT的基因及蛋

  6. Protection Conferred by recombinant Yersinia pestis Antigens Produced by a Rapid and Highly Scalable Plant Expression System

    Science.gov (United States)

    2006-01-24

    signal; CT, synthetic chloroplast targeting sequence; PhiC31, integrase; 6% HIS, histidine tag; MP, movement protein. Fig. 2. Coomassie-stained gels...The level of F1 targeted to chloroplasts was lower, but still detectable on a Coomassie-stained gel (Fig. 2A). We con- Fig. 1. Constructs used in the...apoplastic targeting (lanes 5), chloroplast -targeted antigens (lanes 6), cytosolic-targeted translational fusions with GFP (lanes 7), cytosolic- targeted

  7. Genetic Immunization Elicits Antigen-Specific Protective Immune Responses and Decreases Disease Severity in Trypanosoma cruzi Infection

    OpenAIRE

    2002-01-01

    Immunity to Trypanosoma cruzi requires elicitation of humoral and cell-mediated immune responses to extracellular trypomastigotes and intracellular amastigotes. In this study, the effectiveness of the T. cruzi trans-sialidase family (ts) genes ASP-1, ASP-2, and TSA-1 as genetic vaccines was assessed. Immunization of mice with plasmids encoding ASP-1, ASP-2, or TSA-1 elicited poor antigen-specific cytotoxic-T-lymphocyte (CTL) activity and T. cruzi-specific antibody responses. Codelivery of int...

  8. A Novel Method of Safely Measuring Influenza Virus Aerosol Using Antigen-Capture Enzyme-Linked Immunosorbent Assay for the Performance Evaluation of Protective Clothing Materials.

    Science.gov (United States)

    Shimasaki, Noriko; Nojima, Yasuhiro; Okaue, Akira; Takahashi, Hitoshi; Kageyama, Tsutomu; Hamamoto, Itsuki; Shinohara, Katsuaki

    2016-01-01

    Currently, threats caused by pathogens are serious public health problems worldwide. Protective clothing is essential when one is treating infected patients or dealing with unknown pathogens. Therefore, it is necessary to evaluate the performance of protective clothing against pathogens. In Japan, some methods for evaluating the performance of protective clothing have been established in the Japanese Industrial Standards (JIS). However, a test method against virus aerosols has not been established. Because there is a risk of infection from a live virus during the test, it is necessary to devise a safe method for the virus-aerosol-based test. Here, we propose a new method of safely measuring virus aerosols for the performance evaluation of protective clothing materials. To ensure safety, an inactivated virus was used. As a model virus, the influenza virus was selected owing to the proper small diameter of the virus particles. To quantitatively measure the particle-amount of the inactivated influenza virus, we developed an antigen-capture enzyme-linked immunosorbent assay (ELISA) targeting the M1 protein. Furthermore, we evaluated two materials using our method. Significant differences in the protection performance against the virus aerosol were observed between different sample materials, thereby confirming the applicability of our new method for performance evaluation.

  9. Cationic lipid/DNA complexes (JVRS-100) combined with influenza vaccine (Fluzone) increases antibody response, cellular immunity, and antigenically drifted protection.

    Science.gov (United States)

    Lay, Marla; Callejo, Bernadette; Chang, Stella; Hong, David K; Lewis, David B; Carroll, Timothy D; Matzinger, Shannon; Fritts, Linda; Miller, Christopher J; Warner, John F; Liang, Lily; Fairman, Jeffery

    2009-06-12

    Safe and effective adjuvants for influenza vaccines that could increase both the levels of neutralizing antibody, including against drifted viral subtypes, and T-cell immunity would be a major advance in vaccine design. The JVRS-100 adjuvant, consisting of DOTIM/cholesterol cationic liposome-DNA complexes, is particularly promising for vaccines that require induction of high levels of antibody and T-cell immunity, including CD8(+) cytotoxic T lymphocytes (CTL). Inclusion of protein antigens with JVRS-100 results in the induction of enhanced humoral and cell-mediated (i.e., CD4(+) and CD8(+) T cells) immune responses. The JVRS-100 adjuvant combined with a split trivalent influenza vaccine (Fluzone-sanofi pasteur) elicited increased antibody and T-cell responses in mice and non-human primates compared to vaccination with Fluzone alone. Mice vaccinated with JVRS-100-Fluzone and challenged with antigenically drifted strains of H1N1 (PR/8/34) and influenza B (B/Lee/40) viruses had higher grade protection, as measured by attenuation of weight loss and increased survival, compared to recipients of unadjuvanted vaccine. The results indicate that the JVRS-100 adjuvant substantially increases immunogenicity and protection from drifted-strain challenge using an existing influenza vaccine.

  10. Induction of protection against leishmaniasis in susceptible BALB/c mice using simple DOTAP cationic nanoliposomes containing soluble Leishmania antigen (SLA).

    Science.gov (United States)

    Firouzmand, Hengameh; Badiee, Ali; Khamesipour, Ali; Heravi Shargh, Vahid; Alavizadeh, Seyedeh Hoda; Abbasi, Azam; Jaafari, Mahmoud Reza

    2013-12-01

    A suitable adjuvant and delivery system are needed to develop an effective vaccine against leishmaniasis. To induce a Th1 type of response and protection in BALB/c mice against Leishmania major infection, 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) nanoliposomes bearing an intrinsic adjuvanticity, were used as an antigen delivery system and immunoadjuvant for soluble Leishmania antigens (SLA). DOTAP liposomes containing different concentrations of SLA were prepared by using lipid film method followed by sonication. The prepared vesicles showed a diameter of about 100nm, a positive zeta potential and approximately 70% encapsulation efficiency of SLA. BALB/c mice were immunized subcutaneously (SC), three times in a 3-week interval with different concentrations of liposomal SLA (12.5, 25, and 50μg of SLA/50μl/mice), free SLA and as well as free liposome. The group of mice received 50μg of SLA in DOTAP-nanoliposomes showed a significantly (p<0.001) smaller footpad swelling and the lowest spleen and footpad parasite burden after the challenge. This group also showed the highest IFN-γ production compared to the other groups, lower IL-4 level and higher IgG2a antibody titer. Taken together, the results indicated that simple DOTAP nanoliposome containing 1μg/μl SLA are appropriate delivery systems to induce a Th1 type of immune response and protection against L. major infection in BALB/c mice.

  11. Novel 6xHis tagged foot-and-mouth disease virus vaccine bound to nanolipoprotein adjuvant via metal ions provides antigenic distinction and effective protective immunity

    Energy Technology Data Exchange (ETDEWEB)

    Rai, Devendra K.; Segundo, Fayna Diaz-San [Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, Greenport, NY 11944 (United States); Department of Pathobiology and Veterinary Science, CANR, University of Connecticut, Storrs, CT 06269 (United States); Schafer, Elizabeth [Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, Greenport, NY 11944 (United States); Burrage, Thomas G. [Department of Homeland Security, S & T, Targeted Advance Development, Virus, Cellular and Molecular Imaging Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, Greenport, NY 11944 (United States); Rodriguez, Luis L.; Santos, Teresa de los [Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, Greenport, NY 11944 (United States); Hoeprich, Paul D. [Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA (United States); Rieder, Elizabeth, E-mail: Elizabeth.Rieder@ars.usda.gov [Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, Greenport, NY 11944 (United States)

    2016-08-15

    Here, we engineered two FMD viruses with histidine residues inserted into or fused to the FMDV capsid. Both 6xHis viruses exhibited growth kinetics, plaque morphologies and antigenic characteristics similar to wild-type virus. The 6xHis tag allowed one-step purification of the mutant virions by Co{sup 2+} affinity columns. Electron microscopy and biochemical assays showed that the 6xHis FMDVs readily assembled into antigen: adjuvant complexes in solution, by conjugating with Ni{sup 2+}-chelated nanolipoprotein and monophosphoryl lipid A adjuvant (MPLA:NiNLP). Animals Immunized with the inactivated 6xHis-FMDV:MPLA:NiNLP vaccine acquired enhanced protective immunity against FMDV challenge compared to virions alone. Induction of anti-6xHis and anti-FMDV neutralizing antibodies in the immunized animals could be exploited in the differentiation of vaccinated from infected animals needed for the improvement of FMD control measures. The novel marker vaccine/nanolipid technology described here has broad applications for the development of distinctive and effective immune responses to other pathogens of importance. - Highlights: • 6xHis-tags in A{sub 24} FMDV enable purification and biding to adjuvants via metal ions. • 6xHis A{sub 24} FMDV:MPLA:NiNLP vaccine enhanced protective immunity against FMDV. • Surface exposed capsid tags allow distinction of infected from vaccinated animals.

  12. Use of flagellin and cholera toxin as adjuvants in intranasal vaccination of mice to enhance protective immune responses against uropathogenic Escherichia coli antigens.

    Science.gov (United States)

    Asadi Karam, Mohammad Reza; Habibi, Mehri; Bouzari, Saeid

    2016-09-01

    Urinary tract infections (UTIs) caused by Uropathogenic Escherichia coli (UPEC) are among the most common infections in human. Antibiotics are common therapy for UTIs, but increase in antibiotic resistance will complicate future treatment of the infections, making the development of an efficacious UTI vaccine more urgent. In this study, we have evaluated intranasally the efficacy of FliC and FimH antigens of UPEC in different vaccine formulations with and without cholera toxin (CT) adjuvant. Immunization of mice with FliC in fusion form or admixed with FimH elicited higher levels of serum, mucosal and cell-mediated responses than FimH alone. Furthermore, the use of CT in synergism with FliC resulted in the stimulation of a mixed Th1 and Th2 responses against FimH and FliC as antigen and maintained the antibody responses for at least 24 weeks following the last vaccine dose. Of the vaccine preparations, Fusion, Fusion + CT, and FimH admixed with FliC and CT showed the best protection against UPEC. These data indicated that intranasal administration of a FliC and CT adjuvant-based vaccine has the potential to provide protective responses against UPEC strains.

  13. Evaluation in mice of the immunogenicity and protective efficacy of a tetravalent subunit vaccine candidate against dengue virus.

    Science.gov (United States)

    Lazo, Laura; Izquierdo, Alienys; Suzarte, Edith; Gil, Lázaro; Valdés, Iris; Marcos, Ernesto; Álvarez, Mayling; Romero, Yaremis; Guzmán, María Guadalupe; Guillén, Gerardo; Hermida Cruz, Lisset

    2014-04-01

    A dengue vaccine must induce protective immunity against the four serotypes of the virus. Our group has developed chimeric proteins consisting of the protein P64k from Neisseria meningitidis and the domain III from the four viral envelope proteins. In this study, the immunogenicity of a tetravalent vaccine formulation using aluminum hydroxide as adjuvant was evaluated in mice. After three doses, neutralizing antibody titers were detected against the four viral serotypes, the lowest seroconversion rate being against dengue virus serotype 4. One month after the last dose, immunized animals were challenged with infective virus, and partial but statistically significant protection was found to have been achieved. Based on these results, further studies in mice and non-human primates using this tetravalent formulation in a prime-boost strategy with attenuated viruses are strongly recommended.

  14. Vaccination of sheep against haemonchosis with H11, a gut membrane-derived protective antigen from the adult parasite: prevention of the periparturient rise and colostral transfer of protective immunity.

    Science.gov (United States)

    Andrews, S J; Hole, N J; Munn, E A; Rolph, T P

    1995-07-01

    Pregnant ewes were immunised with a fraction highly enriched in the membrane glycoprotein antigen H11, isolated from the intestinal brush border of adult Haemonchus contortus. Immunity induced by immunisation was able to abolish almost completely (98-99%) the worm egg output from pregnant ewes challenged with ca. 10,000 infective larvae of H. contortus during the last trimester. Furthermore, lambs born and reared on vaccinated ewes had substantial antibody levels to H11 derived from maternal transfer. This antibody conferred moderate protection against a bolus challenge of ca. 3000 infective larvae of H. contortus in 5-week-old lambs.

  15. Protection against multiple influenza A virus strains induced by candidate recombinant vaccine based on heterologous M2e peptides linked to flagellin.

    Directory of Open Access Journals (Sweden)

    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.

  16. Islet antigen-pulsed dendritic cells expressing ectopic IL-35Ig protect nonobese diabetic mice from autoimmune diabetes.

    Science.gov (United States)

    Mondanelli, Giada; Volpi, Claudia; Bianchi, Roberta; Allegrucci, Massimo; Talesa, Vincenzo Nicola; Grohmann, Ursula; Belladonna, Maria Laura

    2015-10-01

    Dendritic cells (DCs) are professional antigen presenting cells capable of orchestrating either stimulatory or regulatory immune responses mediated by T cells. Interleukin 35 (IL-35) is an immunosuppressive, heterodimeric cytokine belonging to the IL-12 family and known to be produced by regulatory T cells but not DCs. In this study, we explored the possible immunosuppressive effect of IL-35 ectopically expressed by splenic DCs from nonobese diabetic (NOD) mice, a prototypical model of autoimmune diabetes. After pulsing with the IGRP peptide (a dominant, diabetogenic autoantigen in NOD mice) and transfer in vivo, IL-35Ig- but not Ig-transfected DCs suppressed antigen specific, T cell-mediated responses in a skin test assay. More importantly, transfer of IL-35Ig-transfected, IGRP-pulsed DCs into prediabetic NOD mice induced a delayed and less severe form of diabetes, an effect accompanied by the increase of CD4(+)CD39(+) suppressive T cells in pancreatic lymph nodes. Our data therefore suggest that DCs overexpressing ectopic IL-35Ig might represent a powerful tool in negative vaccination strategies.

  17. Trypanosoma cruzi as an effective cancer antigen delivery vector.

    Science.gov (United States)

    Junqueira, Caroline; Santos, Luara I; Galvão-Filho, Bruno; Teixeira, Santuza M; Rodrigues, Flávia G; DaRocha, Wanderson D; Chiari, Egler; Jungbluth, Achim A; Ritter, Gerd; Gnjatic, Sacha; Old, Lloyd J; Gazzinelli, Ricardo T

    2011-12-06

    One of the main challenges in cancer research is the development of vaccines that induce effective and long-lived protective immunity against tumors. Significant progress has been made in identifying members of the cancer testis antigen family as potential vaccine candidates. However, an ideal form for antigen delivery that induces robust and sustainable antigen-specific T-cell responses, and in particular of CD8(+) T lymphocytes, remains to be developed. Here we report the use of a recombinant nonpathogenic clone of Trypanosoma cruzi as a vaccine vector to induce vigorous and long-term T cell-mediated immunity. The rationale for using the highly attenuated T. cruzi clone was (i) the ability of the parasite to persist in host tissues and therefore to induce a long-term antigen-specific immune response; (ii) the existence of intrinsic parasite agonists for Toll-like receptors and consequent induction of highly polarized T helper cell type 1 responses; and (iii) the parasite replication in the host cell cytoplasm, leading to direct antigen presentation through the endogenous pathway and consequent induction of antigen-specific CD8(+) T cells. Importantly, we found that parasites expressing a cancer testis antigen (NY-ESO-1) were able to elicit human antigen-specific T-cell responses in vitro and solid protection against melanoma in a mouse model. Furthermore, in a therapeutic protocol, the parasites expressing NY-ESO-1 delayed the rate of tumor development in mice. We conclude that the T. cruzi vector is highly efficient in inducing T cell-mediated immunity and protection against cancer cells. More broadly, this strategy could be used to elicit a long-term T cell-mediated immunity and used for prophylaxis or therapy of chronic infectious diseases.

  18. A Plasmodium vivax plasmid DNA- and adenovirus-vectored malaria vaccine encoding blood stage antigens AMA1 and MSP142 in a prime/boost heterologous immunization regimen partially protects Aotus monkeys against blood stage challenge.

    Science.gov (United States)

    Obaldia, Nicanor; Stockelman, Michael G; Otero, William; Cockrill, Jennifer A; Ganeshan, Harini; Abot, Esteban N; Zhang, Jianfeng; Limbach, Keith; Charoenvit, Yupin; Doolan, Denise L; Tang, De-Chu C; Richie, Thomas L

    2017-02-08

    Malaria is caused by parasites of the genus Plasmodium that are transmitted to humans by the bites of Anopheles mosquitoes. After the elimination of P. falciparum it is predicted that Plasmodium vivax will remain an important cause of morbidity and mortality outside of Africa, stressing the importance of developing a vaccine against malaria. In this study we assess the immunogenicity and protective efficacy of two P. vivax antigens, AMA1 and MSP142 in a recombinant DNA plasmid prime/adenoviral vector (Ad) boost regimen in Aotus monkeys. Groups of 4 to 5 monkeys were immunized with DNA alone, Ad alone, prime/boost regimens of each antigen, prime/boost with both antigens, and empty vector controls, and then subjected to blood stage challenge. The heterologous immunization regimen with the antigen pair was more protective than either antigen alone or both antigens delivered with a single vaccine platform, based on their ability to induced the longest pre-patent period and time to peak parasitemia; the lowest peak and mean parasitemia; the smallest area under the parasitemia curve and the highest self-cured rate. Overall, pre-challenge MSP1 antibody titers strongly correlated with decreased parasite burden. Nevertheless, a significant proportion of immunized animals developed anemia. In conclusion, P. vivax plasmid DNA/Ad5 vaccine encoding blood stage parasite antigens AMA1 and MSP142 in a heterologous prime/boost immunization regimen, provided significant protection against blood-stage challenge in Aotus monkeys, indicating the suitability of these antigens and regimen for further development.

  19. Preliminary evaluation of DNA vaccine candidates encoding dengue-2 prM/E and NS1: their immunity and protective efficacy in mice.

    Science.gov (United States)

    Lu, Hui; Xu, Xiao-Feng; Gao, Na; Fan, Dong-Ying; Wang, Juan; An, Jing

    2013-06-01

    Public health is still seriously threatened by dengue virus (DENV) and no vaccine against DENV is yet available for clinical use till now. In this study, DNA vaccine candidates encoding DENV serotype 2 (DENV-2) prM/E (premembrane and envelope proteins) and NS1 (non-structural 1 protein) with or without a gene adjuvant, granulocyte-macrophage colony-stimulating factor (GM-CSF), were evaluated in the aspects of immunity and protective efficacy in mice. We constructed three plasmids, pCAG-prM/E (which only expressed DENV2 prM/E), pCAG-prM/E/NS1 (which only expressed DENV2 prM/E/NS1) and pCAG-DG (which co-expressed DENV2 prM/E/NS1 and GM-CSF). The expressions of the recombined plasmids were analyzed by immuno-staining in Vero cells. Antibody responses and neutralization activity of the sera from the mice were assayed by ELISA and plaque reduction neutralization test after immunization with the plasmids. Immunized BALB/c mice were intracerebrally challenged with DENV2 to evaluate protective efficacy of the plasmids. The recombinant plasmids could be efficiently expressed in Vero cells and induced different levels of specific anti-DENV2 immune responses. The immunized mice were partially protected. The highest survival rate was observed in the pCAG-DG group although the anti-DENV2 titer and neutralization antibody titer were not the highest among the three groups. Our data suggested that pCAG-DG offered better protection against DENV2 infection.

  20. StreptInCor: a candidate vaccine epitope against S. pyogenes infections induces protection in outbred mice.

    Directory of Open Access Journals (Sweden)

    Edilberto Postol

    Full Text Available Infection with Streptococcus pyogenes (S. pyogenes can result in several diseases, particularly in children. S. pyogenes M protein is the major virulence factor, and certain regions of its N-terminus can trigger autoimmune sequelae such as rheumatic fever in susceptible individuals with untreated group A streptococcal pharyngitis. In a previous study, we utilized a large panel of human peripheral blood cells to define the C-terminal protective epitope StreptInCor (medical identity, which does not induce autoimmune reactions. We recently confirmed the results in HLA-transgenic mice. In the present study, we extended the experimental assays to outbred animals (Swiss mice. Herein, we demonstrate high titers of StreptInCor-specific antibodies, as well as appropriate T-cell immune responses. No cross-reaction to cardiac myosin was detected. Additionally, immunized Swiss mice exhibited 87% survival one month after challenge with S. pyogenes. In conclusion, the data presented herein reinforce previous results in humans and animals and further emphasize that StreptInCor could be an effective and safe vaccine for the prevention of S. pyogenes infections.

  1. Protection Induced by Simultaneous Subcutaneous and Endobronchial Vaccination with BCG/BCG and BCG/Adenovirus Expressing Antigen 85A against Mycobacterium bovis in Cattle.

    Directory of Open Access Journals (Sweden)

    Gillian S Dean

    Full Text Available The incidence of bovine tuberculosis (bTB in the GB has been increasing since the 1980s. Immunisation, alongside current control measures, has been proposed as a sustainable measure to control bTB. Immunisation with Mycobacterium bovis bacillus Calmette-Guerin (BCG has been shown to protect against bTB. Furthermore, much experimental data indicates that pulmonary local immunity is important for protection against respiratory infections including Mycobacterium tuberculosis and that pulmonary immunisation is highly effective. Here, we evaluated protection against M. bovis, the main causative agent of bTB, conferred by BCG delivered subcutaneously, endobronchially or by the new strategy of simultaneous immunisation by both routes. We also tested simultaneous subcutaneous immunisation with BCG and endobronchial delivery of a recombinant type 5 adenovirus expressing mycobacterial antigen 85A. There was significantly reduced visible pathology in animals receiving the simultaneous BCG/BCG or BCG/Ad85 treatment compared to naïve controls. Furthermore, there were significantly fewer advanced microscopic granulomata in animals receiving BCG/Ad85A compared to naive controls. Thus, combining local and systemic immunisation limits the development of pathology, which in turn could decrease bTB transmission.

  2. Protection Against Scrub Typhus by a Plasmid Vaccine Encoding the 56-KD Outer Membrane Protein Antigen Gene

    Science.gov (United States)

    2005-05-27

    Telephone: 301-319-7438, Fax: 301-319-7460, E-mail: chingw@nmrc.navy.mil. Gregory A. Dasch, Viral and Rick- ettsial Zoonoses Branch, Division of...sufficient to mediate protection to an infectious parasite challenge. Proc Natl Acad Sci USA 97: 8427–8432. 41. Rao M, Matyas GR, Grieder F, Anderson

  3. A small antigenic determinant of the Chikungunya virus E2 protein is sufficient to induce neutralizing antibodies which are partially protective in mice.

    Directory of Open Access Journals (Sweden)

    Christopher Weber

    2015-04-01

    Full Text Available The mosquito-borne Chikungunya virus (CHIKV causes high fever and severe joint pain in humans. It is expected to spread in the future to Europe and has recently reached the USA due to globalization, climate change and vector switch. Despite this, little is known about the virus life cycle and, so far, there is no specific treatment or vaccination against Chikungunya infections. We aimed here to identify small antigenic determinants of the CHIKV E2 protein able to induce neutralizing immune responses.E2 enables attachment of the virus to target cells and a humoral immune response against E2 should protect from CHIKV infections. Seven recombinant proteins derived from E2 and consisting of linear and/or structural antigens were created, and were expressed in and purified from E. coli. BALB/c mice were vaccinated with these recombinant proteins and the mouse sera were screened for neutralizing antibodies. Whereas a linear N-terminally exposed peptide (L and surface-exposed parts of the E2 domain A (sA alone did not induce neutralizing antibodies, a construct containing domain B and a part of the β-ribbon (called B+ was sufficient to induce neutralizing antibodies. Furthermore, domain sA fused to B+ (sAB+ induced the highest amount of neutralizing antibodies. Therefore, the construct sAB+ was used to generate a recombinant modified vaccinia virus Ankara (MVA, MVA-CHIKV-sAB+. Mice were vaccinated with MVA-CHIKV-sAB+ and/or the recombinant protein sAB+ and were subsequently challenged with wild-type CHIKV. Whereas four vaccinations with MVA-CHIKV-sAB+ were not sufficient to protect mice from a CHIKV infection, protein vaccination with sAB+ markedly reduced the viral titers of vaccinated mice.The recombinant protein sAB+ contains important structural antigens for a neutralizing antibody response in mice and its formulation with appropriate adjuvants might lead to a future CHIKV vaccine.

  4. A method to identify protein antigens of Dermanyssus gallinae for the protection of birds from poultry mites.

    Science.gov (United States)

    Makert, Gustavo R; Vorbrüggen, Susanne; Krautwald-Junghanns, Maria-Elisabeth; Voss, Matthias; Sohn, Kai; Buschmann, Tilo; Ulbert, Sebastian

    2016-07-01

    The poultry red mite (PRM) Dermanyssus gallinae causes high economic losses and is among the most important parasites in poultry farming worldwide. Different chemical, physical, and biological strategies try to control the expansion of PRM. However, effective solutions to this problem still have to be found. Here, we present a method for the development of an immunological control strategy, based on the identification of mite protein antigens which elicit antibodies with anti-mite activity in the immunized chicken. Hens were immunized with different PRM protein extracts formulated with two different adjuvants, and IgY-antibodies were isolated from the eggs. A PRM in vitro feeding assay which used chicken blood spiked with these IgY-preparations was used to detect antibodies which caused PRM mortality. In vitro feeding of mites with IgY isolated from hens immunized with PRM extract formulated with one of the adjuvants showed a statistically significant increase in the mortality as compared to control mites. After the separation of total PRM extracts in two-dimensional gels, several protein spots were recognized by such IgY preparations. Ten protein spots were subjected to mass spectrometry (MS/MS) for the identification of the corresponding proteins. Complete protein sequences were deduced from genomic and transcriptomic assemblies derived from high throughput sequencing of total PRM DNA and RNA. The results may contribute to the development of an immunological control strategy of D. gallinae.

  5. Multiple Asparagine Deamidation of Bacillus anthracis Protective Antigen Causes Charge Isoforms Whose Complexity Correlates with Reduced Biological Activity

    Science.gov (United States)

    2007-01-01

    Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour...subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1 . REPORT DATE 1 ...FEB 2007 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Multiple asparagine deamidation of Bacillus anthracis protective

  6. Identification of Protective Brucella Antigens and their Expressions in Vaccinia Virus to Prevent Disease in Animals and Humans.

    Science.gov (United States)

    1996-05-01

    cattle, sheep, goats , dogs, and camels. Important species of Brucella are: suis, abortus, ovis, melitensis , canis, and neotomae, each with certain...B. abortus is strain 19 and for protecting goats against B. melitensis is strain Rev 1. Vaccination with these strains leads to seroconversion...encoding the C-terminus portion of the Brucella protein. Western blot analysis of B. abortus and B. melitensis was performed using antibodies raised against

  7. Protective human leucocyte antigen haplotype, HLA-DRB1*01-B*14, against chronic Chagas disease in Bolivia.

    Directory of Open Access Journals (Sweden)

    Florencia del Puerto

    Full Text Available BACKGROUND: Chagas disease, caused by the flagellate parasite Trypanosoma cruzi affects 8-10 million people in Latin America. The mechanisms that underlie the development of complications of chronic Chagas disease, characterized primarily by pathology of the heart and digestive system, are not currently understood. To identify possible host genetic factors that may influence the clinical course of Chagas disease, Human Leucocyte Antigen (HLA regional gene polymorphism was analyzed in patients presenting with differing clinical symptoms. METHODOLOGY: Two hundred and twenty nine chronic Chagas disease patients in Santa Cruz, Bolivia, were examined by serological tests, electrocardiogram (ECG, and Barium enema colon X-ray. 31.4% of the examinees showed ECG alterations, 15.7% megacolon and 58.1% showed neither of them. A further 62 seropositive megacolon patients who had undergone colonectomy due to acute abdomen were recruited. We analyzed their HLA genetic polymorphisms (HLA-A, HLA-B, MICA, MICB, DRB1 and TNF-alpha promoter region mainly through Sequence based and LABType SSO typing test using LUMINEX Technology. PRINCIPAL FINDINGS: The frequencies of HLA-DRB1*01 and HLA-B*14:02 were significantly lower in patients suffering from megacolon as well as in those with ECG alteration and/or megacolon compared with a group of patients with indeterminate symptoms. The DRB1*0102, B*1402 and MICA*011 alleles were in strong Linkage Disequilibrium (LD, and the HLA-DRB1*01-B*14-MICA*011 haplotype was associated with resistance against chronic Chagas disease. CONCLUSIONS: This is the first report of HLA haplotype association with resistance to chronic Chagas disease.

  8. A Novel Synthetic TLR-4 Agonist Adjuvant Increases the Protective Response to a Clinical-Stage West Nile Virus Vaccine Antigen in Multiple Formulations.

    Science.gov (United States)

    Van Hoeven, Neal; Joshi, Sharvari Waghmare; Nana, Ghislain Ismael; Bosco-Lauth, Angela; Fox, Christopher; Bowen, Richard A; Clements, David E; Martyak, Timothy; Parks, D Elliot; Baldwin, Susan; Reed, Steven G; Coler, Rhea N

    2016-01-01

    West Nile virus (WNV) is a mosquito-transmitted member of the Flaviviridae family that has emerged in recent years to become a serious public health threat. Given the sporadic nature of WNV epidemics both temporally and geographically, there is an urgent need for a vaccine that can rapidly provide effective immunity. Protection from WNV infection is correlated with antibodies to the viral envelope (E) protein, which encodes receptor binding and fusion functions. Despite many promising E-protein vaccine candidates, there are currently none licensed for use in humans. This study investigates the ability to improve the immunogenicity and protective capacity of a promising clinical-stage WNV recombinant E-protein vaccine (WN-80E) by combining it with a novel synthetic TLR-4 agonist adjuvant. Using the murine model of WNV disease, we find that inclusion of a TLR-4 agonist in either a stable oil-in-water emulsion (SE) or aluminum hydroxide (Alum) formulation provides both dose and dosage sparing functions, whereby protection can be induced after a single immunization containing only 100 ng of WN-80E. Additionally, we find that inclusion of adjuvant with a single immunization reduced viral titers in sera to levels undetectable by viral plaque assay. The enhanced protection provided by adjuvanted immunization correlated with induction of a Th1 T-cell response and the resultant shaping of the IgG response. These findings suggest that inclusion of a next generation adjuvant may greatly enhance the protective capacity of WNV recombinant subunit vaccines, and establish a baseline for future development.

  9. Phage displaying peptides mimic schistosoma antigenic epitopes selected by rat natural antibodies and protective immunity induced by their immunization in mice

    Institute of Scientific and Technical Information of China (English)

    Min Wang; Xin-Yuan Yi; Xian-Ping Li; Dong-Ming Zhou; McReynolds Larry; Xian-Fang Zeng

    2005-01-01

    AIM: To obtain the short peptides mimic antigenic epitopes selected by rat natural antibodies to schistosomes, and to explore their immunoprotection against schistosomiasis in mice.METHODS: Adults worm antigens (AWA) were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and enzyme-linked transferred immunoblotting methods with normal SD rat sera (NRS). The killing effects on schistosomula with fresh and heat-inactivated sera from SD rats were observed. Then the purified IgG from sera of SD rats was used to biopan a phage random peptide library and 20 randomly selected positive clones were detected by ELISA and 2 of them were sequenced.Sixty female mice were immunized thrice with positive phage clones (0, 2nd, 4th wk). Each mouse was challenged with 40 cercariae, and all mice were killed 42 d after challenge. The worms and the liver eggs were counted. RESULTS: NRS could specifically react to the molecules of 75 000, 47 000, 34 500 and 23 000 of AWA. Sera from SD rats showed that the mortality rate of schistosomula was 76.2%, and when the sera were heat-inactivated in vitro, the mortality rate was decreased to 41.0% after being cultured for 48 h. The specific phages bound to IgG were enriched about 300-folds after three rounds of biopanning. Twenty clones were detected by ELISA, 19 of them bound to the specific IgG of rat sera. Immunization with these epitopes was carried out in mice. Compared with the control groups, the mixture of two mimic peptides could induce 34.9% (P = 0.000) worm reduction and 67.6% (P = 0.000) total liver egg reduction in mice. Two different mimic peptides could respectively induce 31.0% (P = 0.001), 14.5% (P = 0.074) worm reduction and 61.2% (P = 0.000), 35.7% (P = 0.000) total liver egg reduction. The specific antibody could be induced by immunization of the mimic peptides, and the antibody titer in immunized mice reached more than 1:6 400 as detected by ELISA.CONCLUSION: Specific peptides mimic antigenic

  10. Vaccination with Replication Deficient Adenovectors Encoding YF-17D Antigens Induces Long-Lasting Protection from Severe Yellow Fever Virus Infection in Mice.

    Science.gov (United States)

    Bassi, Maria R; Larsen, Mads A B; Kongsgaard, Michael; Rasmussen, Michael; Buus, Søren; Stryhn, Anette; Thomsen, Allan R; Christensen, Jan P

    2016-02-01

    The live attenuated yellow fever vaccine (YF-17D) has been successfully used for more than 70 years. It is generally considered a safe vaccine, however, recent reports of serious adverse events following vaccination have raised concerns and led to suggestions that even safer YF vaccines should be developed. Replication deficient adenoviruses (Ad) have been widely evaluated as recombinant vectors, particularly in the context of prophylactic vaccination against viral infections in which induction of CD8+ T-cell mediated immunity is crucial, but potent antibody responses may also be elicited using these vectors. In this study, we present two adenobased vectors targeting non-structural and structural YF antigens and characterize their immunological properties. We report that a single immunization with an Ad-vector encoding the non-structural protein 3 from YF-17D could elicit a strong CD8+ T-cell response, which afforded a high degree of protection from subsequent intracranial challenge of vaccinated mice. However, full protection was only observed using a vector encoding the structural proteins from YF-17D. This vector elicited virus-specific CD8+ T cells as well as neutralizing antibodies, and both components were shown to be important for protection thus mimicking the situation recently uncovered in YF-17D vaccinated mice. Considering that Ad-vectors are very safe, easy to produce and highly immunogenic in humans, our data indicate that a replication deficient adenovector-based YF vaccine may represent a safe and efficient alternative to the classical live attenuated YF vaccine and should be further tested.

  11. BoHV-4-Based Vector Single Heterologous Antigen Delivery Protects STAT1(-/- Mice from Monkeypoxvirus Lethal Challenge.

    Directory of Open Access Journals (Sweden)

    Valentina Franceschi

    2015-06-01

    Full Text Available Monkeypox virus (MPXV is the etiological agent of human (MPX. It is an emerging orthopoxvirus zoonosis in the tropical rain forest of Africa and is endemic in the Congo-basin and sporadic in West Africa; it remains a tropical neglected disease of persons in impoverished rural areas. Interaction of the human population with wildlife increases human infection with MPX virus (MPXV, and infection from human to human is possible. Smallpox vaccination provides good cross-protection against MPX; however, the vaccination campaign ended in Africa in 1980, meaning that a large proportion of the population is currently unprotected against MPXV infection. Disease control hinges on deterring zoonotic exposure to the virus and, barring that, interrupting person-to-person spread. However, there are no FDA-approved therapies against MPX, and current vaccines are limited due to safety concerns. For this reason, new studies on pathogenesis, prophylaxis and therapeutics are still of great interest, not only for the scientific community but also for the governments concerned that MPXV could be used as a bioterror agent. In the present study, a new vaccination strategy approach based on three recombinant bovine herpesvirus 4 (BoHV-4 vectors, each expressing different MPXV glycoproteins, A29L, M1R and B6R were investigated in terms of protection from a lethal MPXV challenge in STAT1 knockout mice. BoHV-4-A-CMV-A29LgD106ΔTK, BoHV-4-A-EF1α-M1RgD106ΔTK and BoHV-4-A-EF1α-B6RgD106ΔTK were successfully constructed by recombineering, and their capacity to express their transgene was demonstrated. A small challenge study was performed, and all three recombinant BoHV-4 appeared safe (no weight-loss or obvious adverse events following intraperitoneal administration. Further, BoHV-4-A-EF1α-M1RgD106ΔTK alone or in combination with BoHV-4-A-CMV-A29LgD106ΔTK and BoHV-4-A-EF1α-B6RgD106ΔTK, was shown to be able to protect, 100% alone and 80% in combination, STAT1(-/- mice

  12. The Leishmania promastigote surface antigen-2 (PSA-2) is specifically recognised by Th1 cells in humans with naturally acquired immunity to L. major

    DEFF Research Database (Denmark)

    Kemp, M; Handman, E; Kemp, K

    1998-01-01

    The promastigote surface antigen-2 (PSA-2) is a Leishmania parasite antigen, which can induce Th1-mediated protection against murine leishmaniasis when used as a vaccine. To evaluate PSA-2 as a human vaccine candidate the specific T-cell response to PSA-2 was characterised in individuals immune...... to cutaneous leishmaniasis. Peripheral blood mononuclear cells from Sudanese individuals with a past history of self-healing cutaneous leishmaniasis proliferated vigorously in response to PSA-2 isolated from Leishmania major, whereas the antigen did not activate cells from presumably unexposed Danes......-specific Th1-like cells, PSA-2 might be considered a vaccine candidate for human leishmaniasis....

  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. IgG and IgG2 antibodies from cattle naturally infected with Anaplasma marginale recognize the recombinant vaccine candidate antigens VirB9, VirB10, and elongation factor-Tu

    Directory of Open Access Journals (Sweden)

    Flábio R Araújo

    2008-03-01

    Full Text Available Anaplasma marginale is an important vector-borne rickettsia of ruminants in tropical and subtropical regions of the world. Immunization with purified outer membranes of this organism induces protection against acute anaplasmosis. Previous studies, with proteomic and genomic approach identified 21 proteins within the outer membrane immunogen in addition to previously characterized major surface protein1a-5 (MSP1a-5. Among the newly described proteins were VirB9, VirB10, and elongation factor-Tu (EF-Tu. VirB9, VirB10 are considered part of the type IV secretion system (TFSS, which mediates secretion or cell-to-cell transfer of macromolecules, proteins, or DNA-protein complexes in Gram-negative bacteria. EF-Tu can be located in the bacterial surface, mediating bacterial attachment to host cells, or in the bacterial cytoplasm for protein synthesis. However, the roles of VirB9, VirB10, and TFSS in A. marginale have not been defined. VirB9, VirB10, and EF-Tu have not been explored as vaccine antigens. In this study, we demonstrate that sera of cattle infected with A. marginale, with homologous or heterologous isolates recognize recombinant VirB9, VirB10, and EF-Tu. IgG2 from naturally infected cattle also reacts with these proteins. Recognition of epitopes by total IgG and by IgG2 from infected cattle with A. marginale support the inclusion of these proteins in recombinant vaccines against this rickettsia.

  16. Phase I study of safety and immunogenicity of an Escherichia coli-derived recombinant protective antigen (rPA vaccine to prevent anthrax in adults.

    Directory of Open Access Journals (Sweden)

    Bruce K Brown

    Full Text Available BACKGROUND: The fatal disease caused by Bacillus anthracis is preventable with a prophylactic vaccine. The currently available anthrax vaccine requires a lengthy immunization schedule, and simpler and more immunogenic options for protection against anthrax are a priority for development. In this report we describe a phase I clinical trial testing the safety and immunogenicity of an anthrax vaccine using recombinant Escherichia coli-derived, B. anthracis protective antigen (rPA. METHODOLOGY/PRINCIPAL FINDINGS: A total of 73 healthy adults ages 18-40 were enrolled and 67 received 2 injections separated by 4 weeks of either buffered saline placebo, or rPA formulated with or without 704 µg/ml Alhydrogel® adjuvant in increasing doses (5, 25, 50, 100 µg of rPA. Participants were followed for one year and safety and immunologic data were assessed. Tenderness and warmth were the most common post-injection site reactions. No serious adverse events related to the vaccine were observed. The most robust humoral immune responses were observed in subjects receiving 50 µg of rPA formulated with Alhydrogel® with a geometric mean concentration of anti-rPA IgG antibodies of 283 µg/ml and a toxin neutralizing geometric 50% reciprocal geometric mean titer of 1061. The highest lymphoproliferative peak cellular response (median Lymphocyte Stimulation Index of 29 was observed in the group receiving 25 µg Alhydrogel®-formulated rPA. CONCLUSIONS/SIGNIFICANCE: The vaccine was safe, well tolerated and stimulated a robust humoral and cellular response after two doses. TRIAL REGISTRATION: ClinicalTrials.gov NCT00057525.

  17. Myosin-cross-reactive antigen (MCRA) protein from Bifidobacterium breve is a FAD-dependent fatty acid hydratase which has a function in stress protection

    LENUS (Irish Health Repository)

    Rosberg-Cody, Eva

    2011-02-17

    Abstract Background The aim of this study was to determine the catalytic activity and physiological role of myosin-cross-reactive antigen (MCRA) from Bifidobacterium breve NCIMB 702258. MCRA from B. breve NCIMB 702258 was cloned, sequenced and expressed in heterologous hosts (Lactococcus and Corynebacterium) and the recombinant proteins assessed for enzymatic activity against fatty acid substrates. Results MCRA catalysed the conversion of palmitoleic, oleic and linoleic acids to the corresponding 10-hydroxy fatty acids, but shorter chain fatty acids were not used as substrates, while the presence of trans-double bonds and double bonds beyond the position C12 abolished hydratase activity. The hydroxy fatty acids produced were not metabolised further. We also found that heterologous Lactococcus and Corynebacterium expressing MCRA accumulated increasing amounts of 10-HOA and 10-HOE in the culture medium. Furthermore, the heterologous cultures exhibited less sensitivity to heat and solvent stresses compared to corresponding controls. Conclusions MCRA protein in B. breve can be classified as a FAD-containing double bond hydratase, within the carbon-oxygen lyase family, which may be catalysing the first step in conjugated linoleic acid (CLA) production, and this protein has an additional function in bacterial stress protection.

  18. Expression, purification, and characterization of protective MPT64 antigen protein and identification of its multimers isolated from nontoxic Mycobacterium tuberculosis H37Ra.

    Science.gov (United States)

    Chu, Teng-Ping J; Yuann, Jeu-Ming P

    2011-05-01

    MPT64, a secreted protein of Mycobacterium tuberculosis (MTB), stimulates the immune reactions within cells and is a protective antigen that is lost by the bacilli Calmette-Guérin (BCG) vaccine during propagation. To minimize the toxicity caused by MTB, we used the MPT64 gene encoded by nontoxic H37Ra MTB to carry out genetic expansion via polymerase chain reaction and gene clone MPT64. The plasmid DNA encoded MPT64 was expressed at 20°C for 22 H, and a large quantity of MPT64 was obtained. In the absence of urea, MPT64 multimers with subunits being covalently connected via disulfide bonds were detected by Western blot showing strong protein-protein interactions, as evidenced by the formation of MPT64 tetramers. Finally, with urea of decreasing concentrations, we refolded MPT64 purified in the presence of urea and determined its secondary structures using circular dichroism. MPT64 was found to contain 2.2% α-helix, 50.9% β-sheet, 19.5% turn, and 27.4% random coil. The molecular weight of MPT64 was determined by a matrix-assisted laser desorption ionization-time of flight mass spectrometer and found to be 23,497 Da, very close to the theoretical molecular weight of MPT64. The results presented here provide a sound basis for future biochemical and biophysical studies of MPT64 or any other proteins encoded by nontoxic H37Ra MTB.

  19. Regulated delayed expression of rfc enhances the immunogenicity and protective efficacy of a heterologous antigen delivered by live attenuated Salmonella enterica vaccines.

    Science.gov (United States)

    Kong, Qingke; Liu, Qing; Jansen, Angela M; Curtiss, Roy

    2010-08-23

    The Salmonella rfc gene encodes the O-antigen polymerase. We constructed three strains in which we replaced the native rfc promoter with the arabinose-dependent araC P(BAD) promoter so that rfc expression was dependent on exogenously supplied arabinose provided during in vitro growth. The three mutant strains were designed to synthesize different amounts of Rfc by altering the ribosome-binding sequence and start codon. We examined these strains for a number of in vitro characteristics compared to an isogenic Deltarfc mutant and the wild-type parent strain. One promoter-replacement mutation, DeltaP(rfc174), yielded an optimal profile, exhibiting wild-type characteristics when grown with arabinose, and Deltarfc characteristics when grown without arabinose. In addition, when administered orally, the DeltaP(rfc174) strain was completely attenuated in for virulence in mice. The DeltaP(rfc174) mutation was introduced into attenuated Salmonella vaccine strain chi9241 (DeltapabA DeltapabB DeltaasdA) followed by introduction of an Asd(+) balanced-lethal plasmid to designed for expression of the pneumococcal surface protein PspA. Mice immunized with either chi9241 or its DeltaP(rfc174) derivative expressing pspA were protected against S. pneumoniae challenge.

  20. MHC Class II and Non-MHC Class II Genes Differentially Influence Humoral Immunity to Bacillus anthracis Lethal Factor and Protective Antigen

    Directory of Open Access Journals (Sweden)

    Judith A. James

    2012-12-01

    Full Text Available Anthrax Lethal Toxin consists of Protective Antigen (PA and Lethal Factor (LF, and current vaccination strategies focus on eliciting antibodies to PA. In human vaccination, the response to PA can vary greatly, and the response is often directed toward non-neutralizing epitopes. Variable vaccine responses have been shown to be due in part to genetic differences in individuals, with both MHC class II and other genes playing roles. Here, we investigated the relative contribution of MHC class II versus non-MHC class II genes in the humoral response to PA and LF immunization using three immunized strains of inbred mice: A/J (H-2k at the MHC class II locus, B6 (H-2b, and B6.H2k (H-2k. IgG antibody titers to LF were controlled primarily by the MHC class II locus, whereas IgG titers to PA were strongly influenced by the non-MHC class II genetic background. Conversely, the humoral fine specificity of reactivity to LF appeared to be controlled primarily through non-MHC class II genes, while the specificity of reactivity to PA was more dependent on MHC class II. Common epitopes, reactive in all strains, occurred in both LF and PA responses. These results demonstrate that MHC class II differentially influences humoral immune responses to LF and PA.

  1. Mucosal priming of newborn mice with S. Typhi Ty21a expressing anthrax protective antigen (PA) followed by parenteral PA-boost induces B and T cell-mediated immunity that protects against infection bypassing maternal antibodies

    Science.gov (United States)

    Ramirez, Karina; Ditamo, Yanina; Galen, James E.; Baillie, Les W. J.; Pasetti, Marcela F.

    2010-01-01

    The currently licensed anthrax vaccine has several limitations and its efficacy has been proven only in adults. Effective immunization of newborns and infants requires adequate stimulation of their immune system, which is competent but not fully activated. We explored the use of the licensed live attenuated S. Typhi vaccine strain Ty21a expressing Bacillus anthracis protective antigen [Ty21a(PA)] followed PA-alum as a strategy for immunizing the pediatric population. Newborn mice primed with a single dose of Ty21a(PA) exhibited high frequencies of mucosal IgA-secreting B cells and IFN-γ-secreting T cells during the neonatal period, none of which was detected in newborns immunized with a single dose of PA-alum. Priming with Ty21a(PA) followed by PA-boost resulted in high levels of PA-specific IgG, toxin-neutralizing and opsonophagocytic antibodies and increased frequency of bone marrow IgG plasma cells and memory B cells compared with repeated immunization with PA-alum alone. Robust B and T cell responses developed even in the presence of maternal antibodies. The prime-boost protected against systemic and respiratory infection. Mucosal priming with a safe and effective S. Typhi-based anthrax vaccine followed by PA-boost could serve as a practical and effective prophylactic approach to prevent anthrax early in life. PMID:20619377

  2. Attenuated Bordetella pertussis BPZE1 as a live vehicle for heterologous vaccine antigens delivery through the nasal route.

    Science.gov (United States)

    Li, Rui; Lim, Annabelle; Alonso, Sylvie

    2011-01-01

    Whereas the great majority of the current vaccines are delivered through the parenteral route, mucosal administration has been increasingly considered for controlling infection and preventing disease. Mucosal vaccination can trigger both humoral and cell-mediated protection, not only at the targeted mucosal surface, but also systemically. In this regard, nasal vaccination has shown great potential. The live attenuated strain of Bordetella pertussis, BPZE1, is particularly attractive and promising as a nasal vaccine delivery vector of heterologous antigen vaccine candidates. BPZE1 was originally developed as a live nasal pertussis vaccine candidate, and is currently undergoing phase I clinical trial in human (http://www.child-innovac.org). Highly adapted to the human respiratory tract and offering several potential protein carriers for presentation of the heterologous antigen vaccine candidates, BPZE1 represents an appealing platform for the development of live recombinant vaccines delivered via the nasal route that would confer simultaneous protection against pertussis and the targeted infectious disease(s).

  3. Identification of Bacterial Surface Antigens by Screening Peptide Phage Libraries Using Whole Bacteria Cell-Purified Antisera

    Science.gov (United States)

    Hu, Yun-Fei; Zhao, Dun; Yu, Xing-Long; Hu, Yu-Li; Li, Run-Cheng; Ge, Meng; Xu, Tian-Qi; Liu, Xiao-Bo; Liao, Hua-Yuan

    2017-01-01

    Bacterial surface proteins can be good vaccine candidates. In the present study, we used polyclonal antibodies purified with intact Erysipelothrix rhusiopthiae to screen phage-displayed random dodecapeptide and loop-constrained heptapeptide libraries, which led to the identification of mimotopes. Homology search of the mimotope sequences against E. rhusiopthiae-encoded ORF sequences revealed 14 new antigens that may localize on the surface of E. rhusiopthiae. When these putative surface proteins were used to immunize mice, 9/11 antigens induced protective immunity. Thus, we have demonstrated that a combination of using the whole bacterial cells to purify antibodies and using the phage-displayed peptide libraries to determine the antigen specificities of the antibodies can lead to the discovery of novel bacterial surface antigens. This can be a general approach for identifying surface antigens for other bacterial species. PMID:28184219

  4. Antigenicity, Immunogenicity and Protective Efficacy of Three Proteins Expressed in the Promastigote and Amastigote Stages of Leishmania infantum against Visceral Leishmaniasis.

    Directory of Open Access Journals (Sweden)

    Vivian Tamietti Martins

    Full Text Available In the present study, two Leishmania infantum hypothetical proteins present in the amastigote stage, LiHyp1 and LiHyp6, were combined with a promastigote protein, IgE-dependent histamine-releasing factor (HRF; to compose a polyproteins vaccine to be evaluated against L. infantum infection. Also, the antigenicity of the three proteins was analyzed, and their use for the serodiagnosis of canine visceral leishmaniasis (CVL was evaluated. The LiHyp1, LiHyp6, and HRF DNA coding sequences were cloned in prokaryotic expression vectors and the recombinant proteins were purified. When employed in ELISA assays, all proteins were recognized by sera from visceral leishmaniasis (VL dogs, and presented no cross-reactivity with either sera from dogs vaccinated with a Brazilian commercial vaccine, or sera of Trypanosoma cruzi-infected or Ehrlichia canis-infected animals. In addition, the antigens were not recognized by antibodies from non-infected animals living in endemic or non-endemic areas for leishmaniasis. The immunogenicity and protective efficacy of the three proteins administered in the presence of saponin, individually or in combination (composing a polyproteins vaccine, were evaluated in a VL murine model: BALB/c mice infected with L. infantum. Spleen cells from mice inoculated with the individual proteins or with the polyproteins vaccine plus saponin showed a protein-specific production of IFN-γ, IL-12, and GM-CSF after an in vitro stimulation, which was maintained after infection. These animals presented significant reductions in the parasite burden in different evaluated organs, when compared to mice inoculated with saline or saponin. The decrease in parasite burden was associated with an IL-12-dependent production of IFN-γ against parasite total extracts (produced mainly by CD4+ T cells, correlated to the induction of parasite proteins-driven NO production. Mice inoculated with the recombinant protein-based vaccines showed also high levels of

  5. Antigenicity, Immunogenicity and Protective Efficacy of Three Proteins Expressed in the Promastigote and Amastigote Stages of Leishmania infantum against Visceral Leishmaniasis

    Science.gov (United States)

    Martins, Vivian Tamietti; Chávez-Fumagalli, Miguel Angel; Lage, Daniela Pagliara; Duarte, Mariana Costa; Garde, Esther; Costa, Lourena Emanuele; da Silva, Viviane Gomes; Oliveira, Jamil Silvano; de Magalhães-Soares, Danielle Ferreira; Teixeira, Santuza Maria Ribeiro; Fernandes, Ana Paula; Soto, Manuel; Tavares, Carlos Alberto Pereira; Coelho, Eduardo Antonio Ferraz

    2015-01-01

    In the present study, two Leishmania infantum hypothetical proteins present in the amastigote stage, LiHyp1 and LiHyp6, were combined with a promastigote protein, IgE-dependent histamine-releasing factor (HRF); to compose a polyproteins vaccine to be evaluated against L. infantum infection. Also, the antigenicity of the three proteins was analyzed, and their use for the serodiagnosis of canine visceral leishmaniasis (CVL) was evaluated. The LiHyp1, LiHyp6, and HRF DNA coding sequences were cloned in prokaryotic expression vectors and the recombinant proteins were purified. When employed in ELISA assays, all proteins were recognized by sera from visceral leishmaniasis (VL) dogs, and presented no cross-reactivity with either sera from dogs vaccinated with a Brazilian commercial vaccine, or sera of Trypanosoma cruzi-infected or Ehrlichia canis-infected animals. In addition, the antigens were not recognized by antibodies from non-infected animals living in endemic or non-endemic areas for leishmaniasis. The immunogenicity and protective efficacy of the three proteins administered in the presence of saponin, individually or in combination (composing a polyproteins vaccine), were evaluated in a VL murine model: BALB/c mice infected with L. infantum. Spleen cells from mice inoculated with the individual proteins or with the polyproteins vaccine plus saponin showed a protein-specific production of IFN-γ, IL-12, and GM-CSF after an in vitro stimulation, which was maintained after infection. These animals presented significant reductions in the parasite burden in different evaluated organs, when compared to mice inoculated with saline or saponin. The decrease in parasite burden was associated with an IL-12-dependent production of IFN-γ against parasite total extracts (produced mainly by CD4+ T cells), correlated to the induction of parasite proteins-driven NO production. Mice inoculated with the recombinant protein-based vaccines showed also high levels of parasite

  6. Two Epitopes Shared by Taenia crassiceps and Taenia solium Confer Protection against Murine T. crassiceps Cysticercosis along with a Prominent T1 Response

    OpenAIRE

    Toledo, Andrea; Fragoso, Gladis; Rosas, Gabriela; Hernández, Marisela; Gevorkian, Goar; López-Casillas, Fernando; Hernández, Beatriz; Acero, Gonzalo; Huerta, Mirna; Larralde, Carlos; Sciutto, Edda

    2001-01-01

    Taenia crassiceps recombinant antigens KETc1 and KETc12 have been shown to induce high level of protection against experimental murine T. crassiceps cysticercosis, an experimental model successfully used to test candidate antigens for use in vaccination against porcine Taenia solium cysticercosis. Based on the deduced amino acid sequence, KETc1 and KETc12 were chemically synthesized in linear form. Immunization with KETc1 induced 66.7 to 100% protection against murine cysticercosis, and immun...

  7. INNOVATIVE STRATEGIES TO IDENTIFY M. TUBERCULOSIS ANTIGENS AND EPITOPES USING GENOME-WIDE ANALYSES

    Directory of Open Access Journals (Sweden)

    Annemieke eGeluk

    2014-06-01

    Full Text Available In view of the fact that only a small part of the Mtb expressome has been explored for identification of antigens capable of activating human T-cell responses, which is critically required for the design of better TB vaccination strategies, more emphasis should be placed on innovative ways to discover new Mtb antigens and explore their function at the several stages of infection. Better protective antigens for TB vaccines are urgently needed, also in view of the disappointing results of the MVA85 vaccine which failed to induce additional protection in BCG vaccinated infants [54]. Moreover, immune responses to relevant antigens may be useful to identify TB-specific biomarker signatures. Here we describe the potency of novel tools and strategies to reveal such Mtb antigens. Using proteins specific for different Mtb infection phases, many new antigens of the latency-associated Mtb DosR regulon as well as Rpf proteins, associated with resuscitating TB, were discovered that were recognized by CD4+ and CD8+ T-cells. Furthermore, by employing MHC binding algorithms and bioinformatics combined with high throughput human T-cell screens and tetramers, HLA-class Ia restricted poly-functional CD8+ T-cells were identified in TB patients. Comparable methods, led to the identification of HLA-E-restricted Mtb epitopes recognized by CD8+ T-cells. A genome-wide unbiased antigen discovery approach was applied to analyse the in vivo Mtb gene expression profiles in the lungs of mice, resulting in the identification of IVE-TB antigens, which are expressed during infection in the lung, the main target organ of Mtb. IVE-TB antigens induce strong T cell responses in long-term latently Mtb infected individuals, and represent an interesting new group of TB antigens for vaccination. In summary, new tools have helped expand our view on the Mtb antigenome involved in human cellular immunity and provided new candidates for TB vaccination.

  8. Cloning and sequence analysis of the isoforms H11-4 of the vaccine candidate antigen H11 from Haemonchus contortus%捻转血矛线虫ZJ株疫苗候选抗原H11亚型基因H11-4的克隆及序列分析

    Institute of Scientific and Technical Information of China (English)

    段丽君; 周前进; 张红丽; 杨怡; 闫宝龙; 杜爱芳

    2013-01-01

    微粒体氨肽酶H11天然提取物是目前捻转血矛线虫(Haemonchus contortus)防治研究中最好的疫苗候选抗原之一,但其重组形式均不能提供有效的免疫保护效果;同时报道H11蛋白存在多种亚型,推测其某种亚型或亚型组合可能在天然提取物参与免疫保护中起了关键作用.本试验参考NCBI公布的H.contortus H11-4基因序列,设计2对特异性引物,以H.contortus ZJ株总RNA为模板,利用RT-PCR技术分段扩增出该基因的部分片段,并进行T-A克隆.测序正确后,利用含有不同片段的阳性质粒经BamH Ⅰ/Nco Ⅰ消化,连接后获得H11-4基因的全长cDNA序列.测序结果显示成功获得H11 4基因,开放阅读框大小为2 916 bp,与NCBI中公布的核苷酸序列同源性为97.8%,氨基酸序列同源性为97.6%.生物信息学分析,已获得的H11-4与H11 (H11-3)亚型氨基酸序列高度同源,且具有保守糖基化位点、相对保守的跨膜区与微粒体氨肽酶活性中心锌指基序.为进一步分析H11天然提取物各亚型在参与免疫保护的机制和角色分工奠定了基础.%The recombinant microsomal aminopeptidase H11 antigen has not shown highly protective efficacy against Haemonchus contortus compared to its native extract which is considered to be the most efficient vaccine candidate antigen. It is reported that there exist several isoforms of native H11 and it was supposed that one or combined isoforms of native H11 play a key role in immune protection. Fragments of H11-4 gene were amplified by reverse transcription polymerase chain reaction (RT-PCR) with two pairs of primers designed according to the published gene sequence from NCBI. Then the fragments of H11-4 gene were ligated to the T-A cloning vector pMD18-T and sequenced. Positive clones representative the different two fragments were digested with BamH Ⅰ / Nco Ⅰ and then ligated to obtain the full-length cDNA. Sequence analysis shows that with 2 916 bp, H11-4 gene

  9. Recombinant viral-vectored vaccines expressing Plasmodium chabaudi AS apical membrane antigen 1: mechanisms of vaccine-induced blood-stage protection.

    Science.gov (United States)

    Biswas, Sumi; Spencer, Alexandra J; Forbes, Emily K; Gilbert, Sarah C; Holder, Anthony A; Hill, Adrian V S; Draper, Simon J

    2012-05-15

    Apical membrane Ag 1 (AMA1) is one of the leading candidate Ags for inclusion in a subunit vaccine against blood-stage malaria. However, the efficacy of Ab-inducing recombinant AMA1 protein vaccines in phase IIa/b clinical trials remains disappointing. In this article, we describe the development of recombinant human adenovirus serotype 5 and modified vaccinia virus Ankara vectors encoding AMA1 from the Plasmodium chabaudi chabaudi strain AS. These vectors, when used in a heterologous prime-boost regimen in BALB/c mice, are capable of inducing strong transgene-specific humoral and cellular immune responses. We show that this vaccination regimen is protective against a nonlethal P. chabaudi chabaudi strain AS blood-stage challenge, resulting in reduced peak parasitemias. The role of vaccine-induced, AMA1-specific Abs and T cells in mediating the antiparasite effect was investigated by in vivo depletion of CD4(+) T cells and adoptive-transfer studies into naive and immunodeficient mice. Depletion of CD4(+) T cells led to a loss of vaccine-induced protection. Adoptive-transfer studies confirmed that efficacy is mediated by both CD4(+) T cells and Abs functioning in the context of an intact immune system. Unlike previous studies, these results confirm that Ag-specific CD4(+) T cells, induced by a clinically relevant vaccine-delivery platform, can make a significant contribution to vaccine blood-stage efficacy in the P. chabaudi model. Given that cell-mediated immunity may also contribute to parasite control in human malaria, these data support the clinical development of viral-vectored vaccines that induce both T cell and Abs against Plasmodium falciparum blood-stage malaria Ags like AMA1.

  10. Cysteine proteinase type III is protective against Leishmania infantum infection in BALB/c mice and highly antigenic in visceral leishmaniasis individuals.

    Science.gov (United States)

    Khoshgoo, Naghmeh; Zahedifard, Farnaz; Azizi, Hiva; Taslimi, Yasaman; Alonso, Maribel Jiménez; Rafati, Sima

    2008-10-29

    Visceral leishmaniasis is the most acute form of leishmaniasis and vaccination is the best approach to control it. One of the major groups of virulence factors in Leishmania belongs to cysteine proteinase family. In this study, for the first time, the protective potential of Leishmania infantum cysteine proteinase type III (CPC) by using a prime-boost strategy is evaluated in BALB/c mice. The experiment was carried out in three groups of mice. Vaccinated group was primed with pcDNA-cpc and boosted with rCPC-DHFR in combination with CpG motif and Montanide 720 as adjuvant. Control groups received pcDNA and rDHFR or PBS. The ratio of IgG2a/IgG1, nitric oxide concentration and IFN-gamma induction in vaccinated group is significantly higher than controls. Furthermore, the parasite load of vaccinated group is significantly lower than controls. In addition, sera reactivity of visceral leishmaniasis individuals was examined and showed considerable reactivities toward rCPC in comparison with cutaneous leishmaniasis. The achieved result is highly encouraging the use of cysteine proteinases types I, II and III as vaccine candidate against visceral leishmaniasis.

  11. Neem leaf glycoprotein promotes dual generation of central and effector memory CD8(+) T cells against sarcoma antigen vaccine to induce protective anti-tumor immunity.

    Science.gov (United States)

    Ghosh, Sarbari; Sarkar, Madhurima; Ghosh, Tithi; Guha, Ipsita; Bhuniya, Avishek; Saha, Akata; Dasgupta, Shayani; Barik, Subhasis; Bose, Anamika; Baral, Rathindranath

    2016-03-01

    We have previously shown that Neem Leaf Glycoprotein (NLGP) mediates sustained tumor protection by activating host immune response. Now we report that adjuvant help from NLGP predominantly generates CD44(+)CD62L(high)CCR7(high) central memory (TCM; in lymph node) and CD44(+)CD62L(low)CCR7(low) effector memory (TEM; in spleen) CD8(+) T cells of Swiss mice after vaccination with sarcoma antigen (SarAg). Generated TCM and TEM participated either to replenish memory cell pool for sustained disease free states or in rapid tumor eradication respectively. TCM generated after SarAg+NLGP vaccination underwent significant proliferation and IL-2 secretion following SarAg re-stimulation. Furthermore, SarAg+NLGP vaccination helps in greater survival of the memory precursor effector cells at the peak of the effector response and their maintenance as mature memory cells, in comparison to single modality treatment. Such response is corroborated with the reduced phosphorylation of FOXO in the cytosol and increased KLF2 in the nucleus associated with enhanced CD62L, CCR7 expression of lymph node-resident CD8(+) T cells. However, spleen-resident CD8(+) T memory cells show superior efficacy for immediate memory-to-effector cell conversion. The data support in all aspects that SarAg+NLGP demonstrate superiority than SarAg vaccination alone that benefits the host by rapid effector functions whenever required, whereas, central-memory cells are thought to replenish the memory cell pool for ultimate sustained disease free survival till 60 days following post-vaccination tumor inoculation.

  12. Immune protection conferred by recombinant MRLC (myosin regulatory light chain) antigen in TiterMax Gold® adjuvant against experimental fasciolosis in rats.

    Science.gov (United States)

    Henker, Luan C; Schwertz, Claiton I; Lucca, Neuber J; Piva, Manoela M; Prior, Keila C; Baska, Piotr; Norbury, Luke; Januszkiewicz, Kamil; Dezen, Diogenes; Duarte, Marta M M F; Moresco, Rafael N; Bertagnolli da Rosa, Liana; Mendes, Ricardo E

    2017-01-23

    Protection against experimental fasciolosis in rats immunized with recombinant myosin regulatory light chain (MRLC) in TiterMax Gold® adjuvant was assessed. The experimental trial consisted of four groups of 15 animals; group 1 was unimmunized and infected, group 2 was immunized with MRLC in adjuvant and infected, group 3 was infected and immunized with adjuvant only and group 4 was unimmunized and uninfected. Immunization with MRLC in TiterMax Gold® adjuvant (group 2) induced a reduction in fluke burdens of 51.0% (p<0.001) when compared with the adjuvant control group, and 61.5% (p<0.001) when compared with the unimmunized infected controls. There was a reduction in fecal egg output in group 2 of 44.8% and 37.3% compared with group 1 and group 3, respectively; although this difference was not statistically significant. Measurement of cytokine levels revealed higher levels of TNF-alpha and IL-2 as well as lower levels of IL-4 in group 2 during the chronic stage of infection (p<0.05), along with higher levels of IFN-gamma during early stages of infection (p<0.05). These results suggest a mixed Th1/Th2 phenotype immune response; however predominance of Th1 cytokines was observed. Levels of anti-MRLC serum IgG in group 2 were significantly higher than controls at the time of euthanasia (p<0.05). This is the first report of immunization with recombinant MRLC in rats, demonstrating that this antigen significantly reduces fluke burdens, increases the Th1 immune response and encourages further studies to improve the vaccine's efficacy.

  13. Feasibility of asymmetrical flow field-flow fractionation as a method for detecting protective antigen by direct recognition of size-increased target-captured nanoprobes.

    Science.gov (United States)

    Shin, Kayeong; Choi, Jaeyeong; Cho, Jun-Haeng; Yoon, Moon-Young; Lee, Seungho; Chung, Hoeil

    2015-11-27

    Asymmetrical flow field-flow fractionation (AF4) was evaluated as a potential analytical method for detection of a protective antigen (PA), an Anthrax biomarker. The scheme was based on the recognition of altered AF4 retention through the generation of the size-increased Au nanoparticle probes as a result of PA binding, in which a PA-selective peptide was conjugated on the probe surface. In the visible absorption-based AF4 fractograms, the band position shifted to a longer retention time as the PA concentration increased due to the presence of probe bound with PAs. The shift was insignificant when the concentration was relatively low at 84.3pM. To improve sensitivity, two separate probes conjugated with two different peptides able to bind on different PA epitopes were used together. The band shift then became distinguishable even at 84.3pM of PA sample. The formation of larger PA-probe inter-connected species using the dual-probe system was responsible for the enhanced band shift. In parallel, the feasibility of surface-enhanced Raman scattering (SERS) as a potential AF4 detection method was also evaluated. In the off-line SERS fractogram constructed using fractions collected during AF4 separation, a band shift was also observed for the 84.3pM PA sample, and the band intensity was higher when using the dual-probe system. The combination of AF4 and SERS is promising for the detection of PA and will become a potential tool if the reproducibility of SERS measurement is improved.

  14. Structural Characterization of Humanized Nanobodies with Neutralizing Activity against the Bordetella pertussis CyaA-Hemolysin: Implications for a Potential Epitope of Toxin-Protective Antigen.

    Science.gov (United States)

    Malik, Aijaz Ahmad; Imtong, Chompounoot; Sookrung, Nitat; Katzenmeier, Gerd; Chaicumpa, Wanpen; Angsuthanasombat, Chanan

    2016-04-01

    Previously, the 126-kDa CyaA-hemolysin (CyaA-Hly) fragment cloned from Bordetella pertussis--the causative agent of whooping cough--and functionally expressed in Escherichia coli was revealed as a key determinant for CyaA-mediated hemolysis against target erythrocytes. Here, phagemid-transfected E. coli clones producing nanobodies capable of binding to CyaA-Hly were selected from a humanized-camel VH/VHH phage-display library. Subsequently verified for binding activities by indirect ELISA and Western blotting, four CyaA-Hly-specific nanobodies were obtained and designated according to the presence/absence of VHH-hallmark amino acids as VHH2, VH5, VH18 and VHH37. In vitro neutralization assay revealed that all four ~17-kDa His-tagged VH/VHH nanobodies, in particular VHH37, which were over-expressed as inclusions and successfully unfolded-refolded, were able to effectively inhibit CyaA-Hly-mediated hemolysis. Phage-mimotope searching revealed that only peptides with sequence homologous to Linker 1 connecting Blocks I and II within the CyaA-RTX subdomain were able to bind to these four CyaA-Hly-specific nanobodies. Structural analysis of VHH37 via homology modeling and intermolecular docking confirmed that this humanized nanobody directly interacts with CyaA-RTX/Linker 1 through multiple hydrogen and ionic bonds. Altogether, our present data demonstrate that CyaA-RTX/Linker 1 could serve as a potential epitope of CyaA-protective antigen that may be useful for development of peptide-based pertussis vaccines. Additionally, such toxin-specific nanobodies have a potential for test-driven development of a ready-to-use therapeutic in passive immunization for mitigation of disease severity.

  15. Development & validation of a quantitative anti-protective antigen IgG enzyme linked immunosorbent assay for serodiagnosis of cutaneous anthrax

    Directory of Open Access Journals (Sweden)

    N Ghosh

    2015-01-01

    Full Text Available Background & objectives: Anthrax caused by Bacillus anthracis is primarily a disease of herbivorous animals, although several mammals are vulnerable to it. ELISA is the most widely accepted serodiagnostic assay for large scale surveillance of cutaneous anthrax. The aims of this study were to develop and evaluate a quantitative ELISA for determination of IgG antibodies against B. anthracis protective antigen (PA in human cutaneous anthrax cases. Methods: Quantitative ELISA was developed using the recombinant PA for coating and standard reference serum AVR801 for quantification. A total of 116 human test and control serum samples were used in the study. The assay was evaluated for its precision, accuracy and linearity. Results: The minimum detection limit and lower limit of quantification of the assay for anti-PA IgG were 3.2 and 4 µg/ml, respectively. The serum samples collected from the anthrax infected patients were found to have anti-PA IgG concentrations of 5.2 to 166.3 µg/ml. The intra-assay precision per cent CV within an assay and within an operator ranged from 0.99 to 7.4 per cent and 1.7 to 3.9 per cent, respectively. The accuracy of the assay was high with a per cent error of 6.5 - 24.1 per cent. The described assay was found to be linear between the range of 4 to 80 ng/ml (R [2] =0.9982; slope=0.9186; intercept = 0.1108. Interpretation & conclusions: The results suggested that the developed assay could be a useful tool for quantification of anti-PA IgG response in human after anthrax infection or vaccination.

  16. Prime-boost bacillus Calmette-Guérin vaccination with lentivirus-vectored and DNA-based vaccines expressing antigens Ag85B and Rv3425 improves protective efficacy against Mycobacterium tuberculosis in mice.

    Science.gov (United States)

    Xu, Ying; Yang, Enzhuo; Wang, Jianguang; Li, Rui; Li, Guanghua; Liu, Guoyuan; Song, Na; Huang, Qi; Kong, Cong; Wang, Honghai

    2014-10-01

    To prevent the global spread of tuberculosis (TB), more effective vaccines and vaccination strategies are urgently needed. As a result of the success of bacillus Calmette-Guérin (BCG) in protecting children against miliary and meningeal TB, the majority of individuals will have been vaccinated with BCG; hence, boosting BCG-primed immunity will probably be a key component of future vaccine strategies. In this study, we compared the ability of DNA-, protein- and lentiviral vector-based vaccines that express the antigens Ag85B and Rv3425 to boost the effects of BCG in the context of immunity and protection against Mycobacterium tuberculosis in C57BL/6 mice. Our results demonstrated that prime-boost BCG vaccination with a lentiviral vector expressing the antigens Ag85B and Rv3425 significantly enhanced immune responses, including T helper type 1 and CD8(+) cytotoxic T lymphocyte responses, compared with DNA- and protein-based vaccines. However, lentivirus-vectored and DNA-based vaccines greatly improved the protective efficacy of BCG against M. tuberculosis, as indicated by a lack of weight loss and significantly reduced bacterial loads and histological damage in the lung. Our study suggests that the use of lentiviral or DNA vaccines containing the antigens Ag85B and Rv3425 to boost BCG is a good choice for the rational design of an efficient vaccination strategy against TB.

  17. 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.

  18. Phase 1/2a study of the malaria vaccine candidate apical membrane antigen-1 (AMA-l) administered in adjuvant system AS01B or AS02A

    NARCIS (Netherlands)

    M.D. Spring (Michele Donna); J.F. Cummings (James); C.F. Ockenhouse (Christian); S. Dutta (Shantanu); R. Reidler (Randall); E. Angov (Evelina); E. Bergmann-Leitner (Elke); V.A. Stewart (Ann); S. Bittner (Stacey); L. Juompan (Laure); M.G. Kortepeter (Mark); R. Nielsen (Robin); U. Krzych (Urszula); E. Tierney (Ev); L.A. Ware (Lisa); M. Dowler (Megan); C.C. Hermsen (Cornelus); R.W. Sauerwein (Robert); S.J. de Vlas (Sake); O. Ofori-Anyinam (Opokua); D.E. Lanar (David); J.L. Williams (Jack); K.E. Kester (Kent); K. Tucker (Kathryn); M. Shi (Meng); E. Malkin (Elissa); C. Long (Carole); C.L. Diggs (Carter); L. Soisson (Lorraine Amory); M.C. Dubois; W.R. Ballou (Ripley); J. Cohen (Joe); D.G. Heppner (Gray)

    2009-01-01

    textabstractBackground: This Phase 1/2a study evaluated the safety, immunogenicity, and efficacy of an experimental malaria vaccine comprised of the recombinant Plasmodium falciparum protein apical membrane antigen-1 (AMA-1) representing the 3D7 allele formulated with either the AS01B or AS02A Adjuv

  19. Construction of a trivalent candidate Shigella vaccine strain with host-vector balanced-lethal system

    Institute of Scientific and Technical Information of China (English)

    芮贤良; 徐永强; 吴旭东; 苏国富; 黄翠芬

    1997-01-01

    A trivalent live Shigella vaccine candidate FSD01 against S. flexneri 2a, S. sonnei and S. dysen-teriae I was constructed. This candidate strain was based on the S. flexneri 2a vaccine T32. By homologous recombi-nation exchange, the chromosomal asd gene of T32 was site-specifically inactivated, resulting in the strain unable to grow normally in LB broth, while another asd gene of S. mutans was employed to construct an Asd complementary vector. This combination of asd ’host/ Asd+ vector formed a balanced-lethal expression system in T32 strain. By use of this system, two important protective antigen genes coding for S. sonnei Form I antigen and Shiga toxin B subunit were cloned and expressed in T32, which led to the construction of trivalent candidate vaccine FSD01. Experimental results showed that this strain was genetically stable, but its recombinant plasmid was non-resistant. Moreover, it was able to effectively express trivalent antigens in one host and induce protective responses in mice against the

  20. Further characterization of protective Trypanosoma cruzi-specific CD4+ T-cell clones: T helper type 1-like phenotype and reactivity with shed trypomastigote antigens.

    OpenAIRE

    1993-01-01

    We previously reported the isolation from immune mice of a panel of murine clonal T-cell lines which specifically recognize antigens expressed by the trypomastigote stage of the protozoan parasite Trypanosoma cruzi, the causative agent of human Chagas' disease. Our analysis indicated that distinct clones which recognize common as well as strain-specific antigenic determinants were represented. The immunoprotective potential of several of these T-cell clones was demonstrated by adoptive transf...

  1. Identification of a novel Fasciola hepatica cathepsin L protease containing protective epitopes within the propeptide

    NARCIS (Netherlands)

    Harmsen, M.M.; Cornelissen, J.B.W.J.; Buys-Bergen, W.E.C.M.; Boersma, W.J.A.; Jeurissen, S.H.M.; Milligen, F.J.

    2004-01-01

    Cathepsin L (CL)-like proteases are important candidate vaccine antigens for protection against helminth infections. We previously identified an immunogenic 32 kDa protein specifically present in newly excysted juveniles (NEJs) of Fasciola hepatica. Here we show by N-terminal protein sequencing that

  2. Oncogenic cancer/testis antigens

    DEFF Research Database (Denmark)

    Gjerstorff, Morten F; Andersen, Mads H; Ditzel, Henrik J

    2015-01-01

    Recent developments have set the stage for immunotherapy as a supplement to conventional cancer treatment. Consequently, a significant effort is required to further improve efficacy and specificity, particularly the identification of optimal therapeutic targets for clinical testing. Cancer....../testis antigens are immunogenic, highly cancer-specific, and frequently expressed in various types of cancer, which make them promising candidate targets for cancer immunotherapy, including cancer vaccination and adoptive T-cell transfer with chimeric T-cell receptors. Our current understanding of tumor...... immunology and immune escape suggests that targeting oncogenic antigens may be beneficial, meaning that identification of cancer/testis antigens with oncogenic properties is of high priority. Recent work from our lab and others provide evidence that many cancer/testis antigens, in fact, have oncogenic...

  3. Prolonged antigen presentation is required for optimal CD8+ T cell responses against malaria liver stage parasites.

    Directory of Open Access Journals (Sweden)

    Ian A Cockburn

    2010-05-01

    Full Text Available Immunization with irradiated sporozoites is currently the most effective vaccination strategy against liver stages of malaria parasites, yet the mechanisms underpinning the success of this approach are unknown. Here we show that the complete development of protective CD8+ T cell responses requires prolonged antigen presentation. Using TCR transgenic cells specific for the malaria circumsporozoite protein, a leading vaccine candidate, we found that sporozoite antigen persists for over 8 weeks after immunization--a remarkable finding since irradiated sporozoites are incapable of replication and do not differentiate beyond early liver stages. Persisting antigen was detected in lymphoid organs and depends on the presence of CD11c+ cells. Prolonged antigen presentation enhanced the magnitude of the CD8+ T cell response in a number of ways. Firstly, reducing the time primed CD8+ T cells were exposed to antigen in vivo severely reduced the final size of the developing memory population. Secondly, fully developed memory cells expanded in previously immunized mice but not when transferred to naïve animals. Finally, persisting antigen was able to prime naïve cells, including recent thymic emigrants, to become functional effector cells capable of eliminating parasites in the liver. Together these data show that the optimal development of protective CD8+ T cell immunity against malaria liver stages is dependent upon the prolonged presentation of sporozoite-derived antigen.

  4. Studies on cocktails of 31-kDa, 36-kDa and 51-kDa antigens of Leishmania donovani along with saponin against murine visceral leishmaniasis.

    Science.gov (United States)

    Kaur, H; Thakur, A; Kaur, S

    2015-04-01

    A substantial number of antigens of Leishmania donovani have been described in the past. However, identifying candidate antigens is not enough. Appropriate antigen delivery to induce the right type of immune response against leishmaniasis (i.e. induction of a strong antigen-specific Th1 type of immune response) is another crucial component of an effective vaccine. Therefore, 'cocktail' vaccines are proposed based on the assumption that such cocktails will show enhanced efficacy. Studies have been carried out on LD31 and LD51 polypeptides from L. donovani promastigotes, which have proven to be potential vaccine candidates. This study was designed to check the protective efficacy of various cocktails of low molecular weight antigens alone and along with saponin as adjuvant. Mice were sacrificed on different post-challenge days for evaluation of parasite load and other immunological parameters. Protective efficacy of different vaccine formulations was revealed by significant decline in parasite burden and increased DTH Delayed Type Hypersenstivity responses. The antibody response was of IgG type with elevated IgG2a and decreased production of IgG1, whereas cytokine levels pointed towards the generation of protective Th1 type of immune response. Among all vaccine formulations, cocktail of 31+51+saponin was found to be highly immunogenic and imparted maximum protection.

  5. Antigenic Variation in Bacterial Pathogens.

    Science.gov (United States)

    Palmer, Guy H; Bankhead, Troy; Seifert, H Steven

    2016-02-01

    Antigenic variation is a strategy used by a broad diversity of microbial pathogens to persist within the mammalian host. Whereas viruses make use of a minimal proofreading capacity combined with large amounts of progeny to use random mutation for variant generation, antigenically variant bacteria have evolved mechanisms which use a stable genome, which aids in protecting the fitness of the progeny. Here, three well-characterized and highly antigenically variant bacterial pathogens are discussed: Anaplasma, Borrelia, and Neisseria. These three pathogens display a variety of mechanisms used to create the structural and antigenic variation needed for immune escape and long-term persistence. Intrahost antigenic variation is the focus; however, the role of these immune escape mechanisms at the population level is also presented.

  6. Evaluation of the antigenic relatedness and cross-protective immunity of the neuraminidase between human influenza A (H1N1) virus and highly pathogenic avian influenza A (H5N1) virus.

    Science.gov (United States)

    Lu, Xiuhua; Liu, Feng; Zeng, Hui; Sheu, Tiffany; Achenbach, Jenna E; Veguilla, Vic; Gubareva, Larisa V; Garten, Rebecca; Smith, Catherine; Yang, Hua; Stevens, James; Xu, Xiyan; Katz, Jacqueline M; Tumpey, Terrence M

    2014-04-01

    To determine the genetic and antigenic relatedness as well as the cross-protective immunity of human H1N1 and avian H5N1 influenza virus neuraminidase (NA), we immunized rabbits with either a baculovirus-expressed recombinant NA from A/Beijing/262/95 (BJ/262) H1N1 or A/Hong Kong/483/97 (HK/483) H5N1 virus. Cross-reactive antibody responses were evaluated by multiple serological assays and cross-protection against H5N1 virus challenge was evaluated in mice. In a neuraminidase inhibition (NI) test, the antisera exhibited substantial inhibition of NA activity of the homologous virus, but failed to inhibit the NA activity of heterologous virus. However, these antisera exhibited low levels of cross-reactivity measured by plaque size reduction, replication inhibition, single radial hemolysis, and ELISA assays. Passive immunization with HK/483 NA-specific antisera significantly reduced virus replication and disease, and afforded almost complete protection against lethal homologous virus challenge in mice. However, passive immunization with BJ/262 (H1N1) NA-specific antisera was ineffective at providing cross-protection against lethal H5N1 virus challenge and only slightly reduced weight loss. Substantial amino acid variation among the NA antigenic sites was observed between BJ/262 and HK/483 virus, which was consistent with the lack of cross-reactive NI activity by the antibody and limited cross-protective immunity in mice. These results show a strong correlation between the lack of cross-protective immunity and low structural similarities of NA from a human seasonal H1N1 virus and an avian H5N1 influenza virus.

  7. Induction of mucosal immune responses and protection of cattle against direct-contact challenge by intranasal delivery with foot-and-mouth disease virus antigen mediated by nanoparticles

    Directory of Open Access Journals (Sweden)

    Pan L

    2014-12-01

    a double dose of Chi-Tre-Inactivated nanoparticles and animals immunized by intranasal route three times with Chi-Tre-Inactivated nanoparticles (P<0.05. FMDV-specific IgA antibodies in serum showed a similar pattern. All animals immunized by intranasal route developed low levels of detectable IgG in serum at 10 dpv. Following stimulation with FMDV, the highest levels of proliferation were observed in splenocytes harvested from Chi-PLGA-DNA-immunized animals, followed by proliferation of cells harvested from Chi-Tre-Inactivated nanoparticle-immunized animals (P<0.05. Higher protection rates were associated with the highest sIgA antibody responses induced in the Chi-PLGA-DNA nanoparticle-immunized group. Only one animal was clinically affected with mild signs after 7 days of contact challenge, after a delay of 2–3 days compared with the clinically affected negative-control group. Of the five animals directly challenged that were vaccinated by intranasal route with a double dose of Chi-Tre-Inactivated, four were clinically infected; however, the degree of severity of disease in this group was lower than in control cattle. The number of viral RNA copies in nasal swabs from the vaccinated, severely infected group was significantly higher than in swabs from the vaccinated, clinically protected group. These data suggested that intranasal delivery of Chi-PLGA-DNA nanoparticles resulted in higher levels of mucosal, systemic, and cell-mediated immunity than did of Chi-Tre-Inactivated nanoparticles. In conclusion, although intranasal delivery with FMDV antigen mediated by nanoparticles did not provide complete clinical protection, it reduced disease severity and virus excretion and delayed clinical symptoms. Chi-PLGA-DNA nanoparticle vaccines have potential as a nasal delivery system for vaccines. Keywords: FMDV, nanoparticles, chitosan, trehalose, poly(lactic-co-glycolic acid, PLGA

  8. 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) (...

  9. Montanide ISA 71 VG adjuvant enhances antibody and cell-ediated immune responses to profilin subunit antigen vaccination and promotes protection against Eimeria acervulina and Eimeria tenella

    Science.gov (United States)

    The present study was conducted to investigate the immunoenhancing effects of ISA 71 VG adjuvant on profilin subunit antigen vaccination. Broiler chickens were immunized subcutaneously with a purified Eimeria acervulina recombinant profilin protein, either alone or mixed with ISA 71 VG, and host imm...

  10. Novel 6xHis tagged foot-and-mouth disease virus vaccine bound to nanolipoprotein adjuvant via metal ions provides antigenic distinction and effective protective immunity

    Science.gov (United States)

    Here, we engineered two FMD viruses and histidine residues inserted into or fused to the FMDV capsid. Both 6xHis viruses exhibited growth kinetics, plaque morphologies and antigenic characteristics similar to wild-type virus. The 6xHis tag allowed one-step purification of the mutant virions by Co2...

  11. Anti-Lyme Subunit Vaccines: Design and Development of Peptide-Based Vaccine Candidates.

    Science.gov (United States)

    Small, Christina M; Mwangi, Waithaka; Esteve-Gassent, Maria D

    2016-01-01

    Vaccinology today has been presented with several avenues to improve protection against infectious disease. The recent employment of the reverse vaccinology technique has changed the face of vaccine development against many pathogens, including Borrelia burgdorferi, the causative agent of Lyme disease. Using this technique, genomics and in silico analyses come together to identify potentially antigenic epitopes in a high-throughput fashion. The forward methodology of vaccine development was used previously to generate the only licensed human vaccine for Lyme disease, which is no longer on the market. Using reverse vaccinology to identify new antigens and isolate specific epitopes to protect against B. burgdorferi, subunit vaccines will be generated that lack reactogenic and nonspecific epitopes, yielding more effective vaccine candidates. Additionally, novel epitopes are being utilized and are presently in the commercialization pipeline both for B. burgdorferi and other spirochaetal pathogens. The versatility and methodology of the subunit protein vaccine are described as it pertains to Lyme disease from conception to performance evaluation.

  12. Systemic Antibody Responses to the Immunodominant p23 Antigen and p23 Polymorphisms in Children with Cryptosporidiosis in Bangladesh

    OpenAIRE

    Borad, Anoli J.; Allison, Geneve M.; Wang, David; Ahmed, Sabeena; Karim, Mohammad M.; Kane, Anne V.; Moy, Joy; Hibberd, Patricia L.; Rao Ajjampur, Sitara Swarna; Kang, Gagandeep; Calderwood, Stephen B.; Edward T. Ryan; Naumova, Elena; Wasif A. Khan; Ward, Honorine D

    2012-01-01

    Cryptosporidium is a major cause of diarrhea in children in developing countries. However, there is no vaccine available and little is known about immune responses to protective antigens. We investigated antibody responses to p23, a putative vaccine candidate, in children in Bangladesh with cryptosporidiosis and diarrhea (cases) and uninfected children with diarrhea (controls), and p23 gene polymorphisms in infecting species. Serum IgM, IgG, and IgA responses to p23 were significantly greater...

  13. Heterologous protection elicited by candidate monomeric recombinant HIV-1 gp120 vaccine in the absence of cross neutralising antibodies in a macaque model

    Directory of Open Access Journals (Sweden)

    Page Mark

    2012-07-01

    Full Text Available Abstract Background Current data suggest that an efficacious human immunodeficiency virus type 1 (HIV-1 vaccine should elicit both adaptive humoral and cell mediated immune responses. Such a vaccine will also need to protect against infection from a range of heterologous viral variants. Here we have developed a simian-human immunodeficiency virus (SHIV based model in cynomolgus macaques to investigate the breadth of protection conferred by HIV-1W61D recombinant gp120 vaccination against SHIVsbg and SHIVSF33 challenge, and to identify correlates of protection. Results High titres of anti-envelope antibodies were detected in all vaccinees. The antibodies reacted with both the homologous HIV-1W61D and heterologous HIV-1IIIB envelope rgp120 which has an identical sequence to the SHIVsbg challenge virus. Significant titres of virus neutralising antibodies were detected against SHIVW61D expressing an envelope homologous with the vaccine, but only limited cross neutralisation against SHIVsbg, SHIV-4 and SHIVSF33 was observed. Protection against SHIVsbg infection was observed in vaccinated animals but none was observed against SHIVSF33 challenge. Transfer of immune sera from vaccinated macaques to naive recipients did not confer protection against SHIVsbg challenge. In a follow-up study, T cell proliferative responses detected after immunisation with the same vaccine against a single peptide present in the second conserved region 2 of HIV-1 W61D and HIV-1 IIIB gp120, but not SF33 gp120. Conclusions Following extended vaccination with a HIV-1 rgp120 vaccine, protection was observed against heterologous virus challenge with SHIVsbg, but not SHIVSF33. Protection did not correlate with serological responses generated by vaccination, but might be associated with T cell proliferative responses against an epitope in the second constant region of HIV-1 gp120. Broader protection may be obtained with recombinant HIV-1 envelope based vaccines formulated with

  14. Protection of Hamsters by Venezuelan Equine Encephalitis Virus Candidate Vaccine V3526 Against Lethal Challenge by Mosquito Bite and Intraperitoneal Injection

    Science.gov (United States)

    2008-01-01

    the furin cleavage site in PE2 as well as a suppressor mutation in E1, was shown to protect mice, hamsters, and nonhuman primates challenged either by...previously to protect mice, hamsters, and nonhuman primates , there was concern that virus intro- duced by an infected mosquito might be more pathogenic than...and Rift Valley fever virus. Am J Trop Med Hyg 32: 1154–1163. 12. Karabatsos N, ed., 1985. International Catalogue of Arboviruses including Certain

  15. [HLA antigens in juvenile rheumatoid arthritis].

    Science.gov (United States)

    Rumba, I V; Sochnev, A M; Kukaĭne, E M; Burshteĭn, A M; Benevolenskaia, L I

    1990-01-01

    Antigens of I class HLA system (locus A and B) were investigated in 67 patients of Latvian nationality suffering from juvenile rheumatoid arthritis (JRA). Associations of HLA antigens with juvenile rheumatoid arthritis partially coincided with the ones revealed earlier. Typing established an increased incidence of antigen B27 (p less than 0.01) and gaplotype A2, B40 (p less than 0.01). Antigen B15 possessed a protective action with respect to JRA. Interlocus combinations demonstrated a closer association with the disease than a single antigen. The authors also revealed markers of various clinico-anatomical variants of JRA.

  16. 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.

  17. Vaccination with a Streptococcus pneumoniae trivalent recombinant PcpA, PhtD and PlyD1 protein vaccine candidate protects against lethal pneumonia in an infant murine model.

    Science.gov (United States)

    Verhoeven, David; Xu, Qingfu; Pichichero, Michael E

    2014-05-30

    Streptococcus pneumoniae infections continue to cause significant worldwide morbidity and mortality despite the availability of efficacious serotype-dependent vaccines. The need to incorporate emergent strains expressing additional serotypes into pneumococcal polysaccharide conjugate vaccines has led to an identified need for a pneumococcal protein-based vaccine effective against a broad scope of serotypes. A vaccine consisting of several conserved proteins with different functions during pathogenesis would be preferred. Here, we investigated the efficacy of a trivalent recombinant protein vaccine containing pneumococcal choline-binding protein A (PcpA), pneumococcal histidine triad D (PhtD), and genetically detoxified pneumolysin (PlyD1) in an infant mouse model. We found the trivalent vaccine conferred protection from lethal pneumonia challenges using serotypes 6A and 3. The observed protection with trivalent PcpA, PhtD, and PlyD1 vaccine in infant mice supports the ongoing study of this candidate vaccine in human infant clinical trials.

  18. Evaluation of recombinant Neospora caninum antigens purified from silkworm larvae for the protection of N. caninum infection in mice.

    Science.gov (United States)

    Yoshimoto, Mai; Otsuki, Takahiro; Itagaki, Kohei; Kato, Tatsuya; Kohsaka, Tetsuya; Matsumoto, Yumino; Ike, Kazunori; Park, Enoch Y

    2015-12-01

    Three antigens (NcSAG1, NcSRS2 and NcMIC3) from Neospora caninum were expressed using the BmNPV bacmid system in silkworm larvae and purified from the hemolymph. From 20 silkworm larvae, 1.5, 1.2 and 1.4 mg of purified recombinant NcSAG1, NcSRS2 and NcMIC3 were obtained, respectively. When each purified recombinant antigen was immunized with Freund's incomplete adjuvant (FIA) to mice, recombinant NcSAG1 induced a Th2 immune response in immunized mice and produced a SAG1-specific antibody. In the experiment where NcSAG1-immunized mice were challenged with N. caninum, the cerebral N. caninum burden was significantly reduced compared with that of either the FIA- or PBS-immunized mice. Recombinant NcSRS2 or NcMIC3 induced both Th1 and Th2 immune responses, but NcMIC3-immunization did not induce significant production of NcMIC3-specific antibodies. These results suggest that the silkworm can produce recombinant antigens of N. caninum, which can be used as a recombinant vaccine against N. caninum.

  19. Dengue viruses cluster antigenically but not as discrete serotypes

    NARCIS (Netherlands)

    L. Katzelnick (Leah); J.M. Fonville (Judith); G.D. Gromowski (Gregory D.); J.B. Arriaga (Jose Bustos); A. Green (Angela); S.L. James (Sarah ); L. Lau (Louis); M. Montoya (Magelda); C. Wang (Chunling); L.A. Van Blargan (Laura A.); C.A. Russell (Colin); H.M. Thu (Hlaing Myat); T.C. Pierson (Theodore C.); P. Buchy (Philippe); J.G. Aaskov (John G.); J.L. Muñoz-Jordán (Jorge L.); N. Vasilakis (Nikos); R.V. Gibbons (Robert V.); R.B. Tesh (Robert B.); A.D.M.E. Osterhaus (Albert); R.A.M. Fouchier (Ron); A. Durbin (Anna); C.P. Simmons (Cameron P.); E.C. Holmes (Edward C.); E. Harris (Eva); S.S. Whitehead (Stephen S.); D.J. Smith (Derek James)

    2015-01-01

    textabstractThe four genetically divergent dengue virus (DENV) types are traditionally classified as serotypes. Antigenic and genetic differences among the DENV types influence disease outcome, vaccine-induced protection, epidemic magnitude, and viral evolution.We scharacterized antigenic diversity

  20. Comparison of a live attenuated Salmonella Enteritidis vaccine candidate secreting Escherichia coli heat-labile enterotoxin B subunit with a commercial vaccine for efficacy of protection against internal egg contamination by Salmonella in hens.

    Science.gov (United States)

    Nandre, Rahul M; Eo, Seong Kug; Park, Sang Youel; Lee, John Hwa

    2015-07-01

    This study compared a new live attenuated Salmonella Enteritidis vaccine candidate secreting Escherichia coli heat-labile enterotoxin B subunit (SE-LTB) with a commercial Salmonella Enteritidis (SE) vaccine for efficacy of protection against SE infection in laying hens. Chickens were divided into 3 groups of 20 each. Group A chickens were inoculated orally with phosphate-buffered saline and served as controls, group B chickens were inoculated orally with the vaccine candidate, and group C chickens were inoculated intramuscularly with a commercial vaccine, the primary inoculation in groups B and C being at 10 wk of age and the booster at 16 wk. Groups B and C showed significantly higher titers of plasma immunoglobulin G, intestinal secretory immunoglobulin A, and egg yolk immunoglobulin Y antibodies compared with the control group, and both vaccinated groups showed a significantly elevated cellular immune response. After virulent challenge, group B had significantly lower production of thin-shelled and/or malformed eggs and a significantly lower rate of SE contamination of eggs compared with the control group. Furthermore, the challenge strain was detected significantly less in all of the examined organs of group B compared with the control group. Group C had lower gross lesion scores only in the spleen and had lower bacterial counts only in the spleen, ceca, and ovary. These findings indicate that vaccination with the SE-LTB vaccine candidate can efficiently reduce internal egg and internal organ contamination by Salmonella and has advantages over the commercial vaccine.

  1. Antigen pulsed CpG-ODN activated dendritic cells induce host-protective immune response by regulating the T regulatory cell functioning in Leishmania donovani-infected mice: critical role of CXCL10

    Directory of Open Access Journals (Sweden)

    Saikat eMajumder

    2014-06-01

    Full Text Available Visceral leishmaniasis (VL, caused by Leishmania donovani, is a systemic infection of reticulo-endothelial system. There is currently no protective vaccine against VL and chemotherapy is increasingly limited due to appearance of drug resistance to first line drugs such as antimonials and amphotericin B. In the present study, by using a murine model of leishmaniasis we evaluated the function played by soluble leishmanial antigen (SLA pulsed-CpG-ODN stimulated dendritic cells (SLA-CpG-DCs in restricting the intracellular parasitic growth. We establish that a single dose of SLA-CpG-DCs vaccination is sufficient in rendering complete protection against Leishmania donovani infection. In probing the possible mechanism, we observed that SLA-CpG-DCs vaccination results in the significant decrease in Foxp3+GITR+CTLA4+CD4+CD25+ Treg cell population in Leishmania-infected mice. Vaccination with these antigen stimulated dendritic cells results in the decrease in the secretion of TGF-β by these Treg cells by possible regulation of the SMAD signalling. Moreover, we demonstrated that a CXC chemokine, IFN-γ-inducible protein 10 (IP-10, has a direct role in the regulation of CD4+CD25+ Treg cells in SLA-CpG-DCs vaccinated parasitized mice as Treg cells isolated from IP-10 depleted vaccinated mice showed significantly increased TGF-β production and suppressive activity.

  2. Protective

    Directory of Open Access Journals (Sweden)

    Wessam M. Abdel-Wahab

    2013-10-01

    Full Text Available Many active ingredients extracted from herbal and medicinal plants are extensively studied for their beneficial effects. Antioxidant activity and free radical scavenging properties of thymoquinone (TQ have been reported. The present study evaluated the possible protective effects of TQ against the toxicity and oxidative stress of sodium fluoride (NaF in the liver of rats. Rats were divided into four groups, the first group served as the control group and was administered distilled water whereas the NaF group received NaF orally at a dose of 10 mg/kg for 4 weeks, TQ group was administered TQ orally at a dose of 10 mg/kg for 5 weeks, and the NaF-TQ group was first given TQ for 1 week and was secondly administered 10 mg/kg/day NaF in association with 10 mg/kg TQ for 4 weeks. Rats intoxicated with NaF showed a significant increase in lipid peroxidation whereas the level of reduced glutathione (GSH and the activity of superoxide dismutase (SOD, catalase (CAT, glutathione S-transferase (GST and glutathione peroxidase (GPx were reduced in hepatic tissues. The proper functioning of the liver was also disrupted as indicated by alterations in the measured liver function indices and biochemical parameters. TQ supplementation counteracted the NaF-induced hepatotoxicity probably due to its strong antioxidant activity. In conclusion, the results obtained clearly indicated the role of oxidative stress in the induction of NaF toxicity and suggested hepatoprotective effects of TQ against the toxicity of fluoride compounds.

  3. Protection against lethal enterovirus 71 challenge in mice by a recombinant vaccine candidate containing a broadly cross-neutralizing epitope within the VP2 EF loop.

    Science.gov (United States)

    Xu, Longfa; He, Delei; Li, Zhiqun; Zheng, Jun; Yang, Lisheng; Yu, Miao; Yu, Hai; Chen, Yixin; Que, Yuqiong; Shih, James Wai Kuo; Liu, Gang; Zhang, Jun; Zhao, Qinjian; Cheng, Tong; Xia, Ningshao

    2014-01-01

    Human enterovirus 71 (EV71) is the main causative agent of hand, foot, and mouth disease (HFMD) and is associated with several severe neurological complications in the Asia-Pacific region. Here, we evaluated that while passive transfer of neutralizing monoclonal antibody (nMAb) against the VP2 protein protect against lethal EV71 infection in BALB/c mice. Protective nMAb were mapped to residues 141-155 of VP2 by peptide ELISA. High-resolution structural analysis showed that the epitope is part of the VP2 EF loop, which is the "puff" region that forms the "southern rim" of the canyon. Moreover, a three-dimensional structural characterization for the puff region with prior neutralizing epitopes and receptor-binding sites that can serve to inform vaccine strategies. Interestingly, using hepatitis B virus core protein (HBc) as a carrier, we demonstrated that the cross-neutralizing EV71 antibodies were induced, and the VP2 epitope immunized mice serum also conferred 100% in vivo passive protection. The mechanism of in vivo protection conferred by VP2 nMAb is in part attributed to the in vitro neutralizing titer and ability to bind authentic viral particles. Importantly, the anti-VP2(aa141-155) antibodies could inhibit the binding of human serum to EV71 virions showed that the VP2 epitope is immunodominant. Collectively, our results suggest that a broad-spectrum vaccine strategy targeting the high-affinity epitope of VP2 EF loop may elicits effective immune responses against EV71 infection.

  4. A vaccine candidate for post-weaning diarrhea in swine constructed with a live attenuated Salmonella delivering Escherichia coli K88ab, K88ac, FedA, and FedF fimbrial antigens and its immune responses in a murine model.

    Science.gov (United States)

    Hur, Jin; Stein, Barry D; Lee, John Hwa

    2012-07-01

    In order to construct a novel vaccine candidate for preventing post-weaning diarrhea in swine, the individual genes for Escherichia coli K88ab, K88ac, FedA, and FedF fimbriae were inserted into a secretion plasmid pBP244 containing asd, lepB, secA, and secB. These were transformed into Salmonella Typhimurium Δlon ΔcpxR Δasd. Secretion of the individual recombinant fimbrial antigens was confirmed by immunoblot analysis. Groups 1 and 2 mice received a single oral dose of the vaccine mixture and S. Typhimurium carrying pBP244 only as a control, respectively. In groups 3 and 4, mice were primed and boosted with the vaccine mixture and S. Typhimurium carrying pBP244 only as a control, respectively. In general, all immunized mice had significantly increased serum immunoglobulin (Ig)G (P immunized mice. Thus, the vaccine candidate can be highly immunogenic and be safe to the environment.

  5. GD2-specific CAR T Cells Undergo Potent Activation and Deletion Following Antigen Encounter but can be Protected From Activation-induced Cell Death by PD-1 Blockade.

    Science.gov (United States)

    Gargett, Tessa; Yu, Wenbo; Dotti, Gianpietro; Yvon, Eric S; Christo, Susan N; Hayball, John D; Lewis, Ian D; Brenner, Malcolm K; Brown, Michael P

    2016-06-01

    Chimeric antigen receptor (CAR) T cells have shown great promise in the treatment of hematologic malignancies but more variable results in the treatment of solid tumors and the persistence and expansion of CAR T cells within patients has been identified as a key correlate of antitumor efficacy. Lack of immunological "space", functional exhaustion, and deletion have all been proposed as mechanisms that hamper CAR T-cell persistence. Here we describe the events following activation of third-generation CAR T cells specific for GD2. CAR T cells had highly potent immediate effector functions without evidence of functional exhaustion in vitro, although reduced cytokine production reversible by PD-1 blockade was observed after longer-term culture. Significant activation-induced cell death (AICD) of CAR T cells was observed after repeated antigen stimulation, and PD-1 blockade enhanced both CAR T-cell survival and promoted killing of PD-L1(+) tumor cell lines. Finally, we assessed CAR T-cell persistence in patients enrolled in the CARPETS phase 1 clinical trial of GD2-specific CAR T cells in the treatment of metastatic melanoma. Together, these data suggest that deletion also occurs in vivo and that PD-1-targeted combination therapy approaches may be useful to augment CAR T-cell efficacy and persistence in patients.

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

    Directory of Open Access Journals (Sweden)

    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.

  7. Defining the antigenic diversity of Plasmodium falciparum apical membrane antigen 1 and the requirements for a multi-allele vaccine against malaria.

    Directory of Open Access Journals (Sweden)

    Damien R Drew

    Full Text Available Apical Membrane Antigen 1 (AMA1 is a leading malaria vaccine candidate and a target of naturally-acquired human immunity. Plasmodium falciparum AMA1 is polymorphic and in vaccine trials it induces strain-specific protection. This antigenic diversity is a major roadblock to development of AMA1 as a malaria vaccine and understanding how to overcome it is essential. To assess how AMA1 antigenic diversity limits cross-strain growth inhibition, we assembled a panel of 18 different P. falciparum isolates which are broadly representative of global AMA1 sequence diversity. Antibodies raised against four well studied AMA1 alleles (W2Mef, 3D7, HB3 and FVO were tested for growth inhibition of the 18 different P. falciparum isolates in growth inhibition assays (GIA. All antibodies demonstrated substantial cross-inhibitory activity against different isolates and a mixture of the four different AMA1 antibodies inhibited all 18 isolates tested, suggesting significant antigenic overlap between AMA1 alleles and limited antigenic diversity of AMA1. Cross-strain inhibition by antibodies was only moderately and inconsistently correlated with the level of sequence diversity between AMA1 alleles, suggesting that sequence differences are not a strong predictor of antigenic differences or the cross-inhibitory activity of anti-allele antibodies. The importance of the highly polymorphic C1-L region for inhibitory antibodies and potential vaccine escape was assessed by generating novel transgenic P. falciparum lines for testing in GIA. While the polymorphic C1-L epitope was identified as a significant target of some growth-inhibitory antibodies, these antibodies only constituted a minor proportion of the total inhibitory antibody repertoire, suggesting that the antigenic diversity of inhibitory epitopes is limited. Our findings support the concept that a multi-allele AMA1 vaccine would give broad coverage against the diversity of AMA1 alleles and establish new tools to

  8. Enhanced efficacy and immunogenicity of 78kDa antigen formulated in various adjuvants against murine visceral leishmaniasis.

    Science.gov (United States)

    Nagill, Rajeev; Kaur, Sukhbir

    2010-05-21

    Leishmania infection causes localized cutaneous to severe visceral disease in humans and animals. Current control measures, based on antimonial compounds, are not effective because of resistance in Leishmania. Vaccination would be a feasible alternative, but as yet no vaccine to protect humans against infection has been commercialized. Parasite antigens that preferentially stimulate the induction of significant protection through Th1 response presents a rational approach for a vaccine against leishmaniasis. With this view in mind, we investigated the potential of 78kDa antigen of Leishmania donovani alone and along with different adjuvants against murine visceral leishmaniasis. Various adjuvants used along with 78kDa antigen include monophosphoryl lipid A (MPL-A), liposomal encapsulation, recombinant IL-12, autoclaved Leishmania antigen (ALD) and Freund's adjuvant (FCA). BALB/c mice were immunized subcutaneously thrice with respective vaccine formulation. Challenge infection was given intracardially after 2 weeks of second booster. A significant decrease in parasite burden was seen in vaccinees over the infected controls on all post challenge days and was found that maximum protection was provided by 78kDa+rIL-12 vaccine and it was highly immunogenic as depicted by the reduction in parasite load (71-94.8%), reduction in infection rate of peritoneal macrophages (92.9-98%), enhanced DTH response (6.5-10.5 fold), increase in IgG2a anti-leishmanial antibody production (3-3.7 fold) and up-regulation of IFN-gamma (3.7-6.5 fold) and IL-2 levels (7.7-12.3 fold), which demonstrate the generation of protective Th1 type of immune response. Comparable results were also observed in 78kDa+MPL-A and liposome-encapsulated 78kDa vaccines with 56.5-92% and 62.9-93.4% reduction in parasite load respectively. Significant results have also been obtained with 78kDa antigen+ALD, 78kDa antigen+FCA and 78kDa antigen alone group but the protective efficacy was reduced as compared to the

  9. 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.

  10. CD1d-dependent NKT cells play a protective role in acute and chronic arthritis models by ameliorating antigen-specific Th1 responses

    DEFF Research Database (Denmark)

    Teige, Anna; Bockermann, Robert; Hasan, Maruf

    2010-01-01

    A protective and anti-inflammatory role for CD1d-dependent NKT cells (NKTs) has been reported in experimental and human autoimmune diseases. However, their role in arthritis has been unclear, with conflicting reports of CD1d-dependent NKTs acting both as regulatory and disease-promoting cells...

  11. Evaluation of three recombinant multi-antigenic vaccines composed of surface and secretory antigens of Toxoplasma gondii in murine models of experimental toxoplasmosis.

    Science.gov (United States)

    Dziadek, Bozena; Gatkowska, Justyna; Brzostek, Anna; Dziadek, Jaroslaw; Dzitko, Katarzyna; Grzybowski, Marcin; Dlugonska, Henryka

    2011-01-17

    The great clinical and economical impact of Toxoplasma gondii infections makes the development of an effective vaccine for controlling toxoplasmosis an extremely important aim. In the presented study, we evaluate the protective and immunogenic properties of three recombinant subunit vaccines composed of rROP2+rGRA4+rSAG1, rROP2+rROP4+rGRA4 and rROP2+rROP4+rSAG1 proteins of T. gondii in an experimental toxoplasmosis model in the C3H/HeJ and C57BL/6 mouse strains. All three recombinant vaccines induced partial protection as measured by the reduction of brain cyst burden following challenge with five tissue cysts of the low virulence DX T. gondii strain. The level of protection was dependent on the antigen composition of the vaccine and the genetic background of the laboratory animals. The strongest protection against chronic toxoplasmosis was induced in both C3H/HeJ and C57BL/6 mice by the mixture of rhoptry proteins rROP2 and rROP4 combined with tachyzoite major protein rSAG1. The average parasite burden in these groups of mice was reduced by 71% and 90%, respectively, compared to non-vaccinated mice. The observed protective effect was related to the vaccine-induced cellular and humoral immune responses, as measured by the antigen-induced release of the Th1 cytokines IFN-γ and IL-2, the antigen-stimulated proliferation of spleen cells of vaccinated animals in comparison to control animals and the development of systemic antigen-specific IgG1 and IgG2a (C3H/HeJ) or IgG2c (C57BL/6) antibodies. Our studies show that recombinant rROP2, rROP4, rGRA4 and rSAG1 antigens may be promising candidates for a subunit vaccine against toxoplasmosis. Additionally, we demonstrate that the ideal composition of vaccine antigens can be equally effective in mice with different genetic backgrounds and variable levels of innate resistance to toxoplasmosis, resulting in strong protection against T. gondii invasion.

  12. 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

    2007-12-01

    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.

  13. Dendritic cells transfected with scFv from Mab 7.B12 mimicking original antigen gp43 induces protection against experimental Paracoccidioidomycosis.

    Directory of Open Access Journals (Sweden)

    Karen S Ferreira

    Full Text Available Paracoccidioidomycosis (PCM, endemic in Latin America, is a progressive systemic mycosis caused by Paracoccidioides brasiliensis (P. brasiliensis, which primarily attacks lung tissue. Dendritic cells (DCs are able to initiate a response in naïve T cells, and they also participate in Th-cell education. Furthermore, these cells have been used for therapy in several disease models. Here we transfected DCs with a plasmid (pMAC/PS-scFv encoding a single chain variable fragment (scFv of an anti-Id antibody that is capable of mimicking gp43, the main antigenic component of P. brasiliensis. First, Balb/c mice were immunized subcutaneously with pMAC/PS-scFv and, after seven days, scFv protein was presented to the regional lymph nodes cells. Moreover, we showed that the DCs transfected with scFv were capable of efficiently activating proliferation of total lymph node cells and inducing a decrease in lung infection. Therefore, our results suggested that the use of scFv-transfected DCs may be a promising therapy in the paracoccidioidomycosis (PCM model.

  14. Dendritic cells transfected with scFv from Mab 7.B12 mimicking original antigen gp43 induces protection against experimental Paracoccidioidomycosis.

    Science.gov (United States)

    Ferreira, Karen S; Maranhão, Andrea Q; Garcia, Maria C C; Brígido, Marcelo M; Santos, Suelen S; Lopes, José D; Almeida, Sandro R

    2011-01-07

    Paracoccidioidomycosis (PCM), endemic in Latin America, is a progressive systemic mycosis caused by Paracoccidioides brasiliensis (P. brasiliensis), which primarily attacks lung tissue. Dendritic cells (DCs) are able to initiate a response in naïve T cells, and they also participate in Th-cell education. Furthermore, these cells have been used for therapy in several disease models. Here we transfected DCs with a plasmid (pMAC/PS-scFv) encoding a single chain variable fragment (scFv) of an anti-Id antibody that is capable of mimicking gp43, the main antigenic component of P. brasiliensis. First, Balb/c mice were immunized subcutaneously with pMAC/PS-scFv and, after seven days, scFv protein was presented to the regional lymph nodes cells. Moreover, we showed that the DCs transfected with scFv were capable of efficiently activating proliferation of total lymph node cells and inducing a decrease in lung infection. Therefore, our results suggested that the use of scFv-transfected DCs may be a promising therapy in the paracoccidioidomycosis (PCM) model.

  15. Intradermal delivery of Shigella IpaB and IpaD type III secretion proteins: kinetics of cell recruitment and antigen uptake, mucosal and systemic immunity, and protection across serotypes.

    Science.gov (United States)

    Heine, Shannon J; Diaz-McNair, Jovita; Andar, Abhay U; Drachenberg, Cinthia B; van de Verg, Lillian; Walker, Richard; Picking, Wendy L; Pasetti, Marcela F

    2014-02-15

    Shigella is one of the leading pathogens contributing to the vast pediatric diarrheal disease burden in low-income countries. No licensed vaccine is available, and the existing candidates are only partially effective and serotype specific. Shigella type III secretion system proteins IpaB and IpaD, which are conserved across Shigella spp., are candidates for a broadly protective, subunit-based vaccine. In this study, we investigated the immunogenicity and protective efficacy of IpaB and IpaD administered intradermally (i.d.) with a double-mutant of the Escherichia coli heat-labile enterotoxin (dmLT) adjuvant using microneedles. Different dosage levels of IpaB and IpaD, with or without dmLT, were tested in mice. Vaccine delivery into the dermis, recruitment of neutrophils, macrophages, dendritic cells, and Langerhans cells, and colocalization of vaccine Ag within skin-activated APC were demonstrated through histology and immunofluorescence microscopy. Ag-loaded neutrophils, macrophages, dendritic cells, and Langerhans cells remained in the tissue at least 1 wk. IpaB, IpaD, and dmLT-specific serum IgG- and IgG-secreting cells were produced following i.d. immunization. The protective efficacy was 70% against Shigella flexneri and 50% against Shigella sonnei. Similar results were obtained when the vaccine was administered intranasally, with the i.d. route requiring 25-40 times lower doses. Distinctively, IgG was detected in mucosal secretions; secretory IgA, as well as mucosal and systemic IgA Ab-secreting cells, were seemingly absent. Vaccine-induced T cells produced IFN-γ, IL-2, TNF-α, IL-17, IL-4, IL-5, and IL-10. These results demonstrate the potential of i.d. vaccination with IpaB and IpaD to prevent Shigella infection and support further studies in humans.

  16. Immunization of mice with YscF provides protection from Yersinia pestis infections

    Directory of Open Access Journals (Sweden)

    Bradley David S

    2005-06-01

    Full Text Available Abstract Background Yersinia pestis, the causative agent of plague, is a pathogen with a tremendous ability to cause harm and panic in populations. Due to the severity of plague and its potential for use as a bioweapon, better preventatives and therapeutics for plague are desirable. Subunit vaccines directed against the F1 capsular antigen and the V antigen (also known as LcrV of Y. pestis are under development. However, these new vaccine formulations have some possible limitations. The F1 antigen is not required for full virulence of Y. pestis and LcrV has a demonstrated immunosuppressive effect. These limitations could damper the ability of F1/LcrV based vaccines to protect against F1-minus Y. pestis strains and could lead to a high rate of undesired side effects in vaccinated populations. For these reasons, the use of other antigens in a plague vaccine formulation may be advantageous. Results Desired features in vaccine candidates would be antigens that are conserved, essential for virulence and accessible to circulating antibody. Several of the proteins required for the construction or function of the type III secretion system (TTSS complex could be ideal contenders to meet the desired features of a vaccine candidate. Accordingly, the TTSS needle complex protein, YscF, was selected to investigate its potential as a protective antigen. In this study we describe the overexpression, purification and use of YscF as a protective antigen. YscF immunization triggers a robust antibody response to YscF and that antibody response is able to afford significant protection to immunized mice following challenge with Y. pestis. Additionally, evidence is presented that suggests antibody to YscF is likely not protective by blocking the activity of the TTSS. Conclusion In this study we investigated YscF, a surface-expressed protein of the Yersinia pestis type III secretion complex, as a protective antigen against experimental plague infection. Immunization of

  17. Human Leukocyte Antigen (HLA) B27 Allotype-Specific Binding and Candidate Arthritogenic Peptides Revealed through Heuristic Clustering of Data-independent Acquisition Mass Spectrometry (DIA-MS) Data.

    Science.gov (United States)

    Schittenhelm, Ralf B; Sivaneswaran, Saranjah; Lim Kam Sian, Terry C C; Croft, Nathan P; Purcell, Anthony W

    2016-06-01

    Expression of HLA-B27 is strongly associated with ankylosing spondylitis (AS) and other spondyloarthropathies. While this is true for the majority of HLA-B27 allotypes, HLA-B*27:06 and HLA-B*27:09 are not associated with AS. These two subtypes contain polymorphisms that are ideally positioned to influence the bound peptide repertoire. The existence of disease-inducing peptides (so-called arthritogenic peptides) has therefore been proposed that are exclusively presented by disease-associated HLA-B27 allotypes. However, we have recently demonstrated that this segregation of allotype-bound peptides is not the case and that many peptides that display sequence features predicted to favor binding to disease-associated subtypes are also capable of being presented naturally by protective alleles. To further probe more subtle quantitative changes in peptide presentation, we have used a combination of data-independent acquisition (DIA) and multiple reaction monitoring (MRM) mass spectrometry to quantify the abundance of 1646 HLA-B27 restricted peptides across the eight most frequent HLA-B27 allotypes (HLA-B*27:02-HLA-B*27:09). We utilized K means cluster analysis to group peptides with similar allelic binding preferences across the eight HLA-B27 allotypes, which enabled us to identify the most-stringent binding characteristics for each HLA-B27 allotype and further refined their existing consensus-binding motifs. Moreover, a thorough analysis of this quantitative dataset led to the identification of 26 peptides, which are presented in lower abundance by HLA-B*27:06 and HLA-B*27:09 compared with disease-associated HLA-B27 subtypes. Although these differences were observed to be very subtle, these 26 peptides might encompass the sought-after arthritogenic peptide(s).

  18. Variant surface antigen-specific IgG and protection against clinical consequences of pregnancy-associated Plasmodium falciparum malaria

    DEFF Research Database (Denmark)

    Staalsoe, Trine; Shulman, Caroline E; Bulmer, Judith N;

    2004-01-01

    cytometry to measure VSA-specific IgG concentrations in plasma samples taken during child birth from 477 Kenyan women selected from a cohort of 910 women on the basis of HIV-1 status, gravidity, and placental histology. We measured VSA expressed by one placental P falciparum isolate and two isolates......G. No such relation was shown for concentrations of IgG with specificity for non-pregnancy-associated malaria VSA. INTERPRETATION: VSA-PAM-specific IgG protects against low birthweight and maternal anaemia. Our data indicate an important mechanism of clinical protection against malaria and raise hope for the clinical...... effectiveness of a potential VSA-based vaccine against pregnancy-associated malaria....

  19. Protection of Penaeus monodon against white spot syndrome by continuous oral administration of a low concentration of Bacillus subtilis spores expressing the VP28 antigen.

    Science.gov (United States)

    Pham, K-C; Tran, H T T; Van Doan, C; Le, P H; Van Nguyen, A T; Nguyen, H A; Hong, H A; Cutting, S M; Phan, T-N

    2017-03-01

    In this study, Bacillus subtilis spores expressing a chimeric protein, CotB-VP28, were used as a probiotic vaccine to protect black tiger shrimps (Penaeus monodon) against white spot syndrome virus (WSSV) infection. Oral administration of pellets coated with CotB-VP28 spores (at ≥1 × 10(9 ) CFU per g pellet) to shrimps induced immune-relating phenoloxydase activity (PO) in shrimps after 14 days of feeding (prior challenge) and at day 3 post challenge (1·26 and 1·70 fold increase respectively). A 75% protection rate was obtained by continuous feeding of the spore-coated pellets at ≥1 × 10(9 ) CFU per g for 14 days prior to WSSV challenge and during all the postchallenge period. Even when the amount of CotB-VP28 spores in feed pellets was reduced down to ≥5 × 10(7)  CFU per g and ≥1 × 10(6)  CFU per g, relatively high protection rates of 70 and 67·5%, respectively, were still obtained. By contrast, feeding pellets without spores (untreated group) and with naked spores (PY79 group) at ≥1 × 10(9)  CFU per g could not protect shrimps against WSSV. These data suggest that supplementation of CotB-VP28 spores at low dose of ≥1 × 10(6)  CFU per g could be effective as a prophylactic treatment of WSS for black tiger shrimps.

  20. Vaccines based on structure-based design provide protection against infectious diseases.

    Science.gov (United States)

    Thomas, Sunil; Luxon, Bruce A

    2013-11-01

    Vaccines elicit immune responses, provide protection against microorganisms and are considered as one of the most successful medical interventions against infectious diseases. Vaccines can be produced using attenuated virus or bacteria, recombinant proteins, bacterial polysaccharides, carbohydrates or plasmid DNA. Conventional vaccines rely on the induction of immune responses against antigenic proteins to be effective. The genetic diversity of microorganisms, coupled with the high degree of sequence variability in antigenic proteins, presents a challenge to developing broadly effective conventional vaccines. The observation that whole protein antigens are not necessarily essential for inducing immunity has led to the emergence of a new branch of vaccine design termed 'structural vaccinology'. Structure-based vaccines are designed on the rationale that protective epitopes should be sufficient to induce immune responses and provide protection against pathogens. Recent studies demonstrated that designing structure-based vaccine candidates with multiple epitopes induce a higher immune response. As yet there are no commercial vaccines available based on structure-based design and most of the structure-based vaccine candidates are in the preclinical stages of development. This review focuses on recent advances in structure-based vaccine candidates and their application in providing protection against infectious diseases.

  1. Neisseria meningitidis antigen NMB0088: sequence variability, protein topology and vaccine potential.

    Science.gov (United States)

    Sardiñas, Gretel; Yero, Daniel; Climent, Yanet; Caballero, Evelin; Cobas, Karem; Niebla, Olivia

    2009-02-01

    The significance of Neisseria meningitidis serogroup B membrane proteins as vaccine candidates is continually growing. Here, we studied different aspects of antigen NMB0088, a protein that is abundant in outer-membrane vesicle preparations and is thought to be a surface protein. The gene encoding protein NMB0088 was sequenced in a panel of 34 different meningococcal strains with clinical and epidemiological relevance. After this analysis, four variants of NMB0088 were identified; the variability was confined to three specific segments, designated VR1, VR2 and VR3. Secondary structure predictions, refined with alignment analysis and homology modelling using FadL of Escherichia coli, revealed that almost all the variable regions were located in extracellular loop domains. In addition, the NMB0088 antigen was expressed in E. coli and a procedure for obtaining purified recombinant NMB0088 is described. The humoral immune response elicited in BALB/c mice was measured by ELISA and Western blotting, while the functional activity of these antibodies was determined in a serum bactericidal assay and an animal protection model. After immunization in mice, the recombinant protein was capable of inducing a protective response when it was administered inserted into liposomes. According to our results, the recombinant NMB0088 protein may represent a novel antigen for a vaccine against meningococcal disease. However, results from the variability study should be considered for designing a cross-protective formulation in future studies.

  2. Moving candidate vaccines into development from research: lessons from HIV.

    Science.gov (United States)

    Sullivan, Mark

    2009-07-01

    There is a logarithmic increase in the cost and complexity of the research and development process when transitioning a promising candidate vaccine from the laboratory into the clinic. Managing complex development programs involving people from diverse technical, cultural and geographical backgrounds is a specialised skill. It is essential that the group is clear on their objectives and how their activities affect others, that communication is open, inclusive and effective, and that the most rigorous, scientific approach based on statistical principles in compliance with regulatory requirements is used. Applying these standards to all vaccine development programs will filter out inappropriate candidates more readily and enhance the efficiency of vaccine development. The challenges of developing a new vaccine are illustrated in human immunodeficiency virus (HIV) vaccinology. Selecting vaccine candidates for HIV requires the ability to evaluate the large number of potential antigens in imperfect and non-standardised animal models. Further, using these models to evaluate questions such as dose scaling to humans, optimal route of administration, the use of adjuvants and potential formulation improvements adds variable to variable, making the interpretation of results particularly challenging. This may lead to the promotion of a poor candidate or the elimination of a good one. The absence of precise immunological correlates of protection and the prohibitive cost of confirmatory clinical trials are further significant barriers. However, there are practical steps that can be taken to standardise early vaccine evaluation, which would result in more efficient development of new vaccines for HIV and other disease areas with similarly challenging development issues (such as hepatitis C virus, influenza, Mycobacterium tuberculosis and malaria).

  3. Coexpressed Catalase Protects Chimeric Antigen Receptor-Redirected T Cells as well as Bystander Cells from Oxidative Stress-Induced Loss of Antitumor Activity.

    Science.gov (United States)

    Ligtenberg, Maarten A; Mougiakakos, Dimitrios; Mukhopadhyay, Madhura; Witt, Kristina; Lladser, Alvaro; Chmielewski, Markus; Riet, Tobias; Abken, Hinrich; Kiessling, Rolf

    2016-01-15

    Treatment of cancer patients by adoptive T cell therapy has yielded promising results. In solid tumors, however, T cells encounter a hostile environment, in particular with increased inflammatory activity as a hallmark of the tumor milieu that goes along with abundant reactive oxygen species (ROS) that substantially impair antitumor activity. We present a strategy to render antitumor T cells more resilient toward ROS by coexpressing catalase along with a tumor specific chimeric Ag receptor (CAR) to increase their antioxidative capacity by metabolizing H2O2. In fact, T cells engineered with a bicistronic vector that concurrently expresses catalase, along with the CAR coexpressing catalase (CAR-CAT), performed superior over CAR T cells as they showed increased levels of intracellular catalase and had a reduced oxidative state with less ROS accumulation in both the basal state and upon activation while maintaining their antitumor activity despite high H2O2 levels. Moreover, CAR-CAT T cells exerted a substantial bystander protection of nontransfected immune effector cells as measured by CD3ζ chain expression in bystander T cells even in the presence of high H2O2 concentrations. Bystander NK cells, otherwise ROS sensitive, efficiently eliminate their K562 target cells under H2O2-induced oxidative stress when admixed with CAR-CAT T cells. This approach represents a novel means for protecting tumor-infiltrating cells from tumor-associated oxidative stress-mediated repression.

  4. High-resolution characterization of antibody fragment/antigen interactions using Biacore T100.

    Science.gov (United States)

    Papalia, Giuseppe A; Baer, Mark; Luehrsen, Kenneth; Nordin, Helena; Flynn, Peter; Myszka, David G

    2006-12-01

    A Biacore T100 optical biosensor was used to characterize the binding kinetics of a panel of antigen binding fragments (Fabs) directed against the PcrV protein from Pseudomonas aeruginosa. PcrV protein forms part of the type III secretion system complex of this opportunistic pathogen. We demonstrate that the biosensor response data for each Fab collected from three different surface densities of the antigen could be fit globally to a simple 1:1 interaction model. Importantly, we found that the Fabs with the slowest dissociation rate provided the best protection in cell cytotoxicity studies. To further characterize the Fab interactions, binding data were automatically acquired at different temperatures and under different buffer conditions. The comprehensive characterization of these Fabs shows how Biacore T100 can be used to complement protein therapeutic discovery programs from basic research to the selection of therapeutic candidates.

  5. Antigen epitope of Helicobacter pylorivacuolating cytotoxin A

    Institute of Scientific and Technical Information of China (English)

    Xiu-Li Liu; Shu-Qin Li; Chun-Jie Liu; Hao-Xia Tao; Zhao-Shan Zhang

    2004-01-01

    AIM: To construct and select antigen epitopes of vacuolating cytotoxin A (VacA) for nontoxic VacA vaccine against Helicobacter pylori (H pylori) infection.METHODS: Eleven VacA epitopes were predicted according to VacA antigenic bioinformatics. Three candidates of VacA epitope were constructed through different combined epitopes. The candidate was linked with E. coli heat-labile enterotoxin B (LTB) by a linker of 7 amino acids, and cloned into plasmid pQE-60 in which fusion LTB-VacA epitope was efficiently expressed. To test the antigencity of the candidate, 6 BALB/c mice were treated with the fusion LTB-VacA epitope through intraperitoneal injection. To explore the ability of inhibiting the toxicity of VacA, cantiserum against the candidate was used to counteract VacA that induced HeLa cells to produce cell vacuoles in vitro.RESULTS: Serum IgG against the candidate was induced in the BALB/c mice. In vitro, the three antisera against the candidate efficiently counteracted the toxicity of VacA, and decreased the number of cell vacuoles by 14.17%, 20.20%and 30.41% respectively.CONCLUSION: Two of the three candidates, LZ-VacA1and LZ-VacA2, can be used to further study the mechanism of vacuolating toxicity of VacA, and to construct nontoxic VacA vaccine against H pylori infection.

  6. Leishmania genome analysis and high-throughput immunological screening identifies tuzin as a novel vaccine candidate against visceral leishmaniasis.

    Science.gov (United States)

    Lakshmi, Bhavana Sethu; Wang, Ruobing; Madhubala, Rentala

    2014-06-24

    Leishmaniasis is a neglected tropical disease caused by Leishmania species. It is a major health concern affecting 88 countries and threatening 350 million people globally. Unfortunately, there are no vaccines and there are limitations associated with the current therapeutic regimens for leishmaniasis. The emerging cases of drug-resistance further aggravate the situation, demanding rapid drug and vaccine development. The genome sequence of Leishmania, provides access to novel genes that hold potential as chemotherapeutic targets or vaccine candidates. In this study, we selected 19 antigenic genes from about 8000 common Leishmania genes based on the Leishmania major and Leishmania infantum genome information available in the pathogen databases. Potential vaccine candidates thus identified were screened using an in vitro high throughput immunological platform developed in the laboratory. Four candidate genes coding for tuzin, flagellar glycoprotein-like protein (FGP), phospholipase A1-like protein (PLA1) and potassium voltage-gated channel protein (K VOLT) showed a predominant protective Th1 response over disease exacerbating Th2. We report the immunogenic properties and protective efficacy of one of the four antigens, tuzin, as a DNA vaccine against Leishmania donovani challenge. Our results show that administration of tuzin DNA protected BALB/c mice against L. donovani challenge and that protective immunity was associated with higher levels of IFN-γ and IL-12 production in comparison to IL-4 and IL-10. Our study presents a simple approach to rapidly identify potential vaccine candidates using the exhaustive information stored in the genome and an in vitro high-throughput immunological platform.

  7. Vaccination with virus-like particles containing H5 antigens from three H5N1 clades protects chickens from H5N1 and H5N8 influenza viruses.

    Science.gov (United States)

    Kapczynski, Darrell R; Tumpey, Terrence M; Hidajat, Rachmat; Zsak, Aniko; Chrzastek, Klaudia; Tretyakova, Irina; Pushko, Peter

    2016-03-18

    Highly pathogenic avian influenza (HPAI) viruses, especially H5N1 strains, represent a public health threat and cause widespread morbidity and mortality in domestic poultry. Recombinant virus-like particles (VLPs) represent a promising novel vaccine approach to control avian influenza including HPAI strains. Influenza VLPs contain viral hemagglutinin (HA), which can be expressed in cell culture within highly immunogenic VLPs that morphologically and antigenically resemble influenza virions, except VLPs are non-infectious. Here we describe a recombinant VLP containing HA proteins derived from three distinct clades of H5N1 viruses as an experimental, broadly protective H5 avian influenza vaccine. A baculovirus vector was configured to co-express the H5 genes from recent H5N1 HPAI isolates A/chicken/Germany/2014 (clade 2.3.4.4), A/chicken/West Java/Subang/29/2007 (clade 2.1.3) and A/chicken/Egypt/121/2012 (clade 2.2.1). Co-expression of these genes in Sf9 cells along with influenza neuraminidase (NA) and retrovirus gag genes resulted in production of triple-clade H555 VLPs that exhibited hemagglutination activity and morphologically resembled influenza virions. Vaccination of chickens with these VLPs resulted in induction of serum antibody responses and efficient protection against experimental challenges with three different viruses including the recent U.S. H5N8 HPAI isolate. We conclude that these novel triple-clade VLPs represent a feasible strategy for simultaneously evoking protective antibodies against multiple variants of H5 influenza virus.

  8. Antigen selection for future anti-Trichuris vaccines: a comparison of cytokine and antibody responses to larval and adult antigen in a primary infection.

    Science.gov (United States)

    Dixon, H; Johnston, C E; Else, K J

    2008-09-01

    Trichuriasis, caused by the whipworm Trichuris trichiura, is endemic in tropical and subtropical areas, affecting approximately 1 billion people. Child anthelminthic treatment programmes are being implemented but repeated treatments are costly, may prevent the development of acquired immunity and can lead to the development of drug resistant parasites. Thus, the development of a vaccine which would lead to the acquisition of immunity at an earlier age and reduce community faecal egg output would be beneficial. Development of subunit vaccines requires the identification of protective antigens and their formulation in a suitable adjuvant. Trichuris muris is an antigenically similar laboratory model for T. trichiura. Subcutaneous vaccination with adult excretory-secretory products (ES) protects susceptible mouse strains from T. muris. Larval stages may contain novel and more relevant antigens which when incorporated in a vaccine induce worm expulsion earlier in infection than the adult worm products. This study finds negligible difference in the cellular and humoral immune response to T. muris adult and third stage larva(e) (L3) ES during a primary T. muris infection, but identifies high molecular weight proteins in both adult and L3 ES as potential vaccine candidates.

  9. CELLULAR VACCINES IN LISTERIOSIS: ROLE OF THE LISTERIA ANTIGEN GAPDH.

    Directory of Open Access Journals (Sweden)

    Ricardo eCalderon-Gonzalez

    2014-02-01

    Full Text Available The use of live Listeria-based vaccines carries serious difficulties when administrated to immunocompromised individuals. However, cellular carriers have the advantage of inducing multivalent innate immunity as well as cell-mediated immune responses, constituting novel and secure vaccine strategies in listeriosis. Here, we compare the protective efficacy of dendritic cells (DCs and macrophages and their safety. We examined the immune response of these vaccine vectors using two Listeria antigens, listeriolysin O (LLO and glyceraldehyde-3-phosphate-dehydrogenase (GAPDH, and several epitopes such as the LLO peptides, LLO189–201 and LLO91–99 and the GAPDH peptide, GAPDH1–22. We discarded macrophages as safe vaccine vectors because they show anti-Listeria protection but also high cytotoxicity. DCs loaded with GAPDH1–22 peptide conferred higher protection and security against listeriosis than the widely explored LLO91–99 peptide. Anti-Listeria protection was related to the changes in DC maturation caused by these epitopes, with high production of interleukin-12 as well as significant levels of other Th1 cytokines such as monocyte chemotactic protein-1, tumor necrosis factor-α, and interferon-γ, and with the induction of GAPDH1–22-specific CD4+ and CD8+ immune responses. This is believed to be the first study to explore the use of a novel GAPDH antigen as a potential DC-based vaccine candidate for listeriosis, whose efficiency appears to highlight the relevance of vaccine designs containing multiple CD4+ and CD8+ epitopes.

  10. Cellular vaccines in listeriosis: role of the Listeria antigen GAPDH

    Science.gov (United States)

    Calderón-González, Ricardo; Frande-Cabanes, Elisabet; Bronchalo-Vicente, Lucía; Lecea-Cuello, M. Jesús; Pareja, Eduardo; Bosch-Martínez, Alexandre; Fanarraga, Mónica L.; Yañez-Díaz, Sonsoles; Carrasco-Marín, Eugenio; Álvarez-Domínguez, Carmen

    2014-01-01

    The use of live Listeria-based vaccines carries serious difficulties when administrated to immunocompromised individuals. However, cellular carriers have the advantage of inducing multivalent innate immunity as well as cell-mediated immune responses, constituting novel and secure vaccine strategies in listeriosis. Here, we compare the protective efficacy of dendritic cells (DCs) and macrophages and their safety. We examined the immune response of these vaccine vectors using two Listeria antigens, listeriolysin O (LLO) and glyceraldehyde-3-phosphate-dehydrogenase (GAPDH), and several epitopes such as the LLO peptides, LLO189−201 and LLO91−99 and the GAPDH peptide, GAPDH1−22. We discarded macrophages as safe vaccine vectors because they show anti-Listeria protection but also high cytotoxicity. DCs loaded with GAPDH1−22 peptide conferred higher protection and security against listeriosis than the widely explored LLO91−99 peptide. Anti-Listeria protection was related to the changes in DC maturation caused by these epitopes, with high production of interleukin-12 as well as significant levels of other Th1 cytokines such as monocyte chemotactic protein-1, tumor necrosis factor-α, and interferon-γ, and with the induction of GAPDH1−22-specific CD4+ and CD8+ immune responses. This is believed to be the first study to explore the use of a novel GAPDH antigen as a potential DC-based vaccine candidate for listeriosis, whose efficiency appears to highlight the relevance of vaccine designs containing multiple CD4+ and CD8+ epitopes. PMID:24600592

  11. Cellular vaccines in listeriosis: role of the Listeria antigen GAPDH.

    Science.gov (United States)

    Calderón-González, Ricardo; Frande-Cabanes, Elisabet; Bronchalo-Vicente, Lucía; Lecea-Cuello, M Jesús; Pareja, Eduardo; Bosch-Martínez, Alexandre; Fanarraga, Mónica L; Yañez-Díaz, Sonsoles; Carrasco-Marín, Eugenio; Alvarez-Domínguez, Carmen

    2014-01-01

    The use of live Listeria-based vaccines carries serious difficulties when administrated to immunocompromised individuals. However, cellular carriers have the advantage of inducing multivalent innate immunity as well as cell-mediated immune responses, constituting novel and secure vaccine strategies in listeriosis. Here, we compare the protective efficacy of dendritic cells (DCs) and macrophages and their safety. We examined the immune response of these vaccine vectors using two Listeria antigens, listeriolysin O (LLO) and glyceraldehyde-3-phosphate-dehydrogenase (GAPDH), and several epitopes such as the LLO peptides, LLO189-201 and LLO91-99 and the GAPDH peptide, GAPDH1-22. We discarded macrophages as safe vaccine vectors because they show anti-Listeria protection but also high cytotoxicity. DCs loaded with GAPDH1-22 peptide conferred higher protection and security against listeriosis than the widely explored LLO91-99 peptide. Anti-Listeria protection was related to the changes in DC maturation caused by these epitopes, with high production of interleukin-12 as well as significant levels of other Th1 cytokines such as monocyte chemotactic protein-1, tumor necrosis factor-α, and interferon-γ, and with the induction of GAPDH1-22-specific CD4(+) and CD8(+) immune responses. This is believed to be the first study to explore the use of a novel GAPDH antigen as a potential DC-based vaccine candidate for listeriosis, whose efficiency appears to highlight the relevance of vaccine designs containing multiple CD4(+) and CD8(+) epitopes.

  12. 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.

  13. Antigenic characterization of avian influenza H9 subtype isolated from desi and zoo birds

    Directory of Open Access Journals (Sweden)

    Farrukh Saleem

    2011-08-01

    Full Text Available Avian influenza is a viral infection which affects mainly the respiratory system of birds. The H9N2 considered as low pathogenic avian influenza (LPAI virus and continuously circulating in poultry flocks causing enormous economic losses to poultry industry of Pakistan. As these viruses have RNA genome and their RNA polymerase enzyme lacks proof reading activity which resulted in spontaneous mutation in surface glycoproteins (HA and NA and reassortment of their genomic segments results in escape from host immune response produced by the vaccine. Efforts made for the isolation and identification of avian influenza virus from live desi and zoo birds of Lahore and performed antigenic characterization. The local vaccines although gives a little bit less titer when we raise the antisera against these vaccines but their antisera have more interaction with the local H9 subtype antigen so it gives better protective immune response. Infected chicken antisera are more reactive as compare to rabbit antisera. This shows that our isolates have highest similarity with the currently circulating viruses. These results guided us to devise a new control strategy against avian influenza viral infections. The antigenic characterization of these avian influenza isolates helped us to see the antigenic differences between the isolates of this study and H9 subtype avian influenza viruses used in vaccines. Therefore, this study clearly suggests that a new local H9 subtype avian influenza virus should be used as vaccinal candidate every year for the effective control of influenza viral infections of poultry.

  14. Strategies for designing and monitoring malaria vaccines targeting diverse antigens

    Directory of Open Access Journals (Sweden)

    Alyssa E Barry

    2014-07-01

    Full Text Available After more than 50 years of intensive research and development, only one malaria vaccine candidate, RTS,S, has progressed to Phase 3 clinical trials. Despite only partial efficacy, this candidate is now forecast to become the first licensed malaria vaccine. Hence, more efficacious second-generation malaria vaccines that can significantly reduce transmission are urgently needed. This review will focus on a major obstacle hindering development of effective malaria vaccines: parasite antigenic diversity. Despite extensive genetic diversity in leading candidate antigens, vaccines have been and continue to be formulated using recombinant antigens representing only one or two strains. These vaccine strains represent only a small fraction of the diversity circulating in natural parasite populations, leading to escape of non-vaccine strains and challenging investigators’ abilities to measure strain-specific efficacy in vaccine trials. Novel strategies are needed to overcome antigenic diversity in order for vaccine development to succeed. Many studies have now catalogued the global diversity of leading Plasmodium falciparum and Plasmodium vivax vaccine antigens. In this review, we describe how population genetic approaches can be applied to this rich data source to predict the alleles that best represent antigenic diversity, polymorphisms that contribute to it, and to identify key polymorphisms associated with antigenic escape. We also suggest an approach to summarise the known global diversity of a given antigen to predict antigenic diversity, how to select variants that best represent the strains circulating in natural parasite populations and how to investigate the strain-specific efficacy of vaccine trials. Use of these strategies in the design and monitoring of vaccine trials will not only shed light on the contribution of genetic diversity to the antigenic diversity of malaria, but will also maximise the potential of future malaria vaccine

  15. Novel methods for expression of foreign antigens in live vector vaccines

    Science.gov (United States)

    Wang, Jin Yuan; Harley, Regina H.; Galen, James E.

    2013-01-01

    Bacterial live vector vaccines represent a vaccine development strategy that offers exceptional flexibility. In this approach, genes encoding protective antigens of unrelated bacterial, viral or parasitic pathogens are expressed in an attenuated bacterial vaccine strain that delivers these foreign antigens to the immune system, thereby eliciting relevant immune responses. Rather than expressing these antigens using low copy expression plasmids, here we pursue expression of foreign proteins from the live vector chromosome. Our strategy is designed to compensate for the inherent disadvantage of loss of gene dosage (vs. plasmid-based expression) by integrating antigen-encoding gene cassettes into multiple chromosomal sites already inactivated in an attenuated Salmonella enterica serovar Typhi vaccine candidate. We tested expression of a cassette encoding the green fluorescent protein (GFPuv) integrated separately into native guaBA, htrA or clyA chromosomal loci. Using single integrations, we show that expression levels of GFPuv are significantly affected by the site of integration, regardless of the inclusion of additional strong promoters within the incoming cassette. Using cassettes integrated into both guaBA and htrA, we observe cumulative synthesis levels from two integration sites superior to single integrations. Most importantly, we observe that GFPuv expression increases in a growth phase-dependent manner, suggesting that foreign antigen synthesis may be “tuned” to the physiology of the live vaccine. We expect this novel platform expression technology to prove invaluable in the development of a wide variety of multivalent live vector vaccines, capable of expressing multiple antigens from both chromosomal and plasmid-based expression systems within a single strain. PMID:23406777

  16. Probing vaccine antigens against bovine mastitis caused by Streptococcus uberis.

    Science.gov (United States)

    Collado, Rosa; Prenafeta, Antoni; González-González, Luis; Pérez-Pons, Josep Antoni; Sitjà, Marta

    2016-07-19

    Streptococcus uberis is a worldwide pathogen that causes intramammary infections in dairy cattle. Because virulence factors determining the pathogenicity of S. uberis have not been clearly identified so far, a commercial vaccine is not yet available. Different S. uberis strains have the ability to form biofilm in vitro, although the association of this kind of growth with the development of mastitis is unknown. The objective of this study was to evaluate the potential use as vaccine antigens of proteins from S. uberis biofilms, previously identified by proteomic and immunological analyses. The capability of eliciting a protective immune response by targeted candidates was assayed on a murine model. Sera from rabbits immunized with S. uberis biofilm preparations and a convalescent cow intra-mammary infected with S. uberis were probed against cell wall proteins from biofilm and planktonic cells previously separated by two-dimensional gel electrophoresis. Using rabbit immunized serum, two proteins were found to be up-regulated in biofilm cells as compared to planktonic cells; when serum from the convalescent cow was used, up to sixteen biofilm proteins were detected. From these proteins, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), fructose-biphosphate aldolase (FBA), and elongation factor Ts (EFTs) were chosen to be tested as vaccine antigen candidates. For this purpose, different groups of mice were immunized with the three recombinant-expressed proteins (each one formulated separately in a vaccine), and thereafter intraperitoneally challenged with S. uberis. The three proteins induced specific IgG antibodies, but a significant reduction of mortality was only observed in the groups of mice vaccinated with FBA or EFTs. These results suggest that FBA and EFTs might be considered as strong antigenic candidates for a vaccine against S. uberis bovine mastitis. Moreover, this is the first study to indicate that also in S. uberis, GAPDH, FBA and EFTs, as proteins

  17. Comparison of purified 12 kDa and recombinant 15 kDa Fasciola hepatica antigens related to a Schistosoma mansoni fatty acid binding protein

    Directory of Open Access Journals (Sweden)

    George V. Hillyer

    1995-04-01

    Full Text Available Vaccines in schistosomiasis using homologous antigens have been studied extensively in experimentally infected mammalian hosts. Vaccines using heterologous antigens have received comparatively less attention. This review summarizes recent work on a heterologous 12 kDa Fasciola hepatica antigenic polypeptide which cross reacts with Schistosoma mansoni. A cDNA has been cloned and sequenced, and the predicted amino acid sequence of the recombinant protein has been shown to have significant (44 identity with a 14 kDa S. mansoni fatty acid binding protein. Thus in the parasitic trematodes fatty acid binding proteins may be potential vaccine candidates. The F. hepatica recombinant protein has been overexpressed and purified and denoted rFh15. Preliminary rFh15 migrates more slowly (i.e. may be slightly larger than nFh12 on SDS-PAGE and has a predicted pI of 6.01 vs. observed pI of 5.45. Mice infected with F. hepatica develop antibodies to nFh12 by 2 weeks of infection vs. 6 weeks of infection to rFh15; on the other hand, mice with schistosomiasis mansoni develop antibodies to both nFh12 and rFh15 by 6 weeks of infection. Both the F. hepatica and S. mansoni cross-reactive antigens may be cross-protective antigens with the protection inducing capability against both species.

  18. In silico design, cloning and high level expression of L7/L12-TOmp31 fusion protein of Brucella antigens

    OpenAIRE

    Golshani, Maryam; Rafati, Sima; Jahanian-Najafabadi, Ali; Nejati-Moheimani, Mehdi; Siadat, Seyed Davar; Shahcheraghi, Fereshteh; Bouzari, Saeid

    2015-01-01

    Globally, Brucella melitensis and B. abortus are the most common cause of human brucellosis. The outer membrane protein 31 (Omp31) and L7/L12 are immunodominant and protective antigens conserved in human Brucella pathogens which are considered as potential vaccine candidates. We aimed to design the fusion protein from Brucella L7/L12 and truncated Omp31proteins, in silico, clone the fusion in pET28a vector, and express it in Escherichia coli host. Two possible fusion forms, L7/L12-TOmp31 and ...

  19. Strategies to enhance immunogenicity of cDNA vaccine encoded antigens by modulation of antigen processing

    NARCIS (Netherlands)

    Platteel, Anouk C M; Marit de Groot, A; Andersen, Peter; Ovaa, Huib; Kloetzel, Peter M; Mishto, Michele; Sijts, Alice J A M

    2016-01-01

    Most vaccines are based on protective humoral responses while for intracellular pathogens CD8(+) T cells are regularly needed to provide protection. However, poor processing efficiency of antigens is often a limiting factor in CD8(+) T cell priming, hampering vaccine efficacy. The multistage cDNA va

  20. Independent candidates in Mexico

    OpenAIRE

    Campos, Gonzalo Santiago

    2014-01-01

    In this paper we discuss the issue of independent candidates in Mexico, because through the so-called political reform of 2012 was incorporated in the Political Constitution of the Mexican United States the right of citizens to be registered as independent candidates. Also, in September 2013 was carried out a reform of Article 116 of the Political Constitution of the Mexican United States in order to allow independent candidates in each state of the Republic. However, prior to the constitutio...

  1. Polymorphisms of transporter associated with antigen presentation, tumor necrosis factor-α and interleukin-10 and their implications for protection and susceptibility to severe forms of dengue fever in patients in Sri Lanka

    Directory of Open Access Journals (Sweden)

    Anira N Fernando

    2015-01-01

    Full Text Available Context: To date, a clear understanding of dengue disease pathogenesis remains elusive. Some infected individuals display no symptoms while others develop severe life-threatening forms of the disease. It is widely believed that host genetic factors influence dengue severity. Aims: This study evaluates the relationship between certain polymorphisms and dengue severity in Sri Lankan patients. Settings and Design: Polymorphism studies are carried out on genes for; transporter associated with antigen presentation (TAP, promoter of tumor necrosis factor-α (TNF-α, and promoter of interleukin-10 (IL-10. In other populations, TAP1 (333, TAP2 (379, TNF-α (−308, and IL-10 (−1082, −819, −592 have been associated with dengue and a number of different diseases. Data have not been collected previously for these polymorphisms for dengue patients in Sri Lanka. Materials and Methods: The polymorphisms were typed by amplification refractory mutation system polymerase chain reaction in 107 dengue hemorrhagic fever (DHF patients together with 62 healthy controls. Statistical Analysis Used: Pearson′s Chi-square contingency table analysis with Yates′ correction. Results: Neither the TAP nor the IL-10 polymorphisms considered individually can define dengue disease outcome with regard to severity. However, the genotype combination, IL-10 (−592/−819/−1082 CCA/ATA was significantly associated with development of severe dengue in these patients, suggesting a risk factor to developing DHF. Also, identified is the genotype combination IL-10 (−592/−819/−1082 ATA/ATG which suggested a possibility for protection from DHF. The TNF-α (−308 GG genotype was also significantly associated with severe dengue, suggesting a significant risk factor. Conclusions: The results reported here are specific to the Sri Lankan population. Comparisons with previous reports imply that data may vary from population to population.

  2. Vaccination of Goats with 31 kDa and 32 kDa Schistosoma japonicum Antigens by DNA Priming and Protein Boosting

    Institute of Scientific and Technical Information of China (English)

    Lianfei Tang; Zhijun Zhou; Yuxiao Chen; Yonghui Luo; Linqian Wang; Liyu Chen; Fushen Huang; Xianfang Zeng; Xinyuan Yi

    2007-01-01

    Two Schistosoma japonicum vaccine candidate antigens Sj 31 and Sj 32, which have shown particular promise to induce protective immunity in mice, were used to immunize goats by using a DNA priming-protein boosting strategy in present work. DNA vaccine formulations of the two antigens (VRSj31 and VRSj32) were produced and injected intramuscularly twice at a 2-week interval and then recombinant proteins (rSj31 and rSj32) together with Freund Complete Adjuvant (FCA) were used to boost the goats. The experiment was repeated in different batche cercariae. A strong anamnestic antibody response was induced after boost. A significant reduction of liver egg counts and miracidial hatching was showed in both experiments. Significant protections against challenge infection were elicited with 31.6% of percentage reduction for worm recovery in the second experiment and 20.9% in the first experiment, respectively.

  3. Comparative evaluation of two vaccine candidates against experimental leishmaniasis due to Leishmania major infection in four inbred mouse strains.

    Science.gov (United States)

    Benhnini, Fouad; Chenik, Mehdi; Laouini, Dhafer; Louzir, Hechmi; Cazenave, Pierre André; Dellagi, Koussay

    2009-11-01

    Experimental leishmaniasis in BALB/c and C57BL/6 mice are the most investigated murine models that were used for the preclinical evaluation of Leishmania vaccine candidates. We have previously described two new inbred mouse strains named PWK and MAI issued from feral founders that also support the development of experimental leishmaniasis due to L. major. In this study, we sought to determine whether different mouse inbred strains generate concordant or discordant results when used to evaluate the potential of Leishmania proteins to protect against experimental leishmaniasis. To this end, two Leishmania proteins, namely, LACK (for Leishmania homolog of receptor for activated C kinase) and LmPDI (for L. major protein disulfide isomerase) were compared for their capacity to protect against experimental leishmaniasis in PWK, MAI, BALB/c, and C57BL/6 inbred mouse strains. Our data show that the capacity of Leishmania proteins to confer protection depends on the mouse strain used, stressing the important role played by the genetic background in shaping the immune response against the pathogen. These results may have important implications for the preclinical evaluation of candidate Leishmania vaccines: rather than using a single mouse strain, a panel of different inbred strains of various genetic backgrounds should be tested in parallel. The antigen that confers protection in the larger range of inbred strains may have better chances to be also protective in outbred human populations and should be selected for clinical trials.

  4. Comparative Evaluation of Two Vaccine Candidates against Experimental Leishmaniasis Due to Leishmania major Infection in Four Inbred Mouse Strains▿

    Science.gov (United States)

    Benhnini, Fouad; Chenik, Mehdi; Laouini, Dhafer; Louzir, Hechmi; Cazenave, Pierre André; Dellagi, Koussay

    2009-01-01

    Experimental leishmaniasis in BALB/c and C57BL/6 mice are the most investigated murine models that were used for the preclinical evaluation of Leishmania vaccine candidates. We have previously described two new inbred mouse strains named PWK and MAI issued from feral founders that also support the development of experimental leishmaniasis due to L. major. In this study, we sought to determine whether different mouse inbred strains generate concordant or discordant results when used to evaluate the potential of Leishmania proteins to protect against experimental leishmaniasis. To this end, two Leishmania proteins, namely, LACK (for Leishmania homolog of receptor for activated C kinase) and LmPDI (for L. major protein disulfide isomerase) were compared for their capacity to protect against experimental leishmaniasis in PWK, MAI, BALB/c, and C57BL/6 inbred mouse strains. Our data show that the capacity of Leishmania proteins to confer protection depends on the mouse strain used, stressing the important role played by the genetic background in shaping the immune response against the pathogen. These results may have important implications for the preclinical evaluation of candidate Leishmania vaccines: rather than using a single mouse strain, a panel of different inbred strains of various genetic backgrounds should be tested in parallel. The antigen that confers protection in the larger range of inbred strains may have better chances to be also protective in outbred human populations and should be selected for clinical trials. PMID:19726616

  5. Immunogenic and invasive properties of Brucella melitensis 16M outer membrane protein vaccine candidates identified via a reverse vaccinology approach.

    Directory of Open Access Journals (Sweden)

    Gabriel Gomez

    Full Text Available Brucella is the etiologic agent of brucellosis, one of the most common and widely distributed zoonotic diseases. Its highly infectious nature, the insidious, systemic, chronic, debilitating aspects of the disease and the lack of an approved vaccine for human use in the United States are features that make Brucella a viable threat to public health. One of the main impediments to vaccine development is identification of suitable antigens. In order to identify antigens that could potentially be used in a vaccine formulation, we describe a multi-step antigen selection approach. We initially used an algorithm (Vaxign to predict ORF encoding outer membrane proteins with antigenic determinants. Differential gene expression during acute infection and published evidence for a role in virulence were used as criteria for down-selection of the candidate antigens that resulted from in silico prediction. This approach resulted in the identification of nine Brucella melitensis outer membrane proteins, 5 of which were recombinantly expressed and used for validation. Omp22 and Hia had the highest in silico scores for adhesin probability and also conferred invasive capacity to E. coli overexpressing recombinant proteins. With the exception of FlgK in the goat, all proteins reacted to pooled sera from exposed goats, mice, and humans. BtuB, Hia and FlgK stimulated a mixed Th1-Th2 response in splenocytes from immunized mice while BtuB and Hia elicited NO release from splenocytes of S19 immunized mice. The results support the applicability of the current approach to the identification of antigens with immunogenic and invasive properties. Studies to assess immunogenicity and protective efficacy of individual proteins in the mouse are currently underway.

  6. Immunogenic and invasive properties of Brucella melitensis 16M outer membrane protein vaccine candidates identified via a reverse vaccinology approach.

    Science.gov (United States)

    Gomez, Gabriel; Pei, Jianwu; Mwangi, Waithaka; Adams, L Garry; Rice-Ficht, Allison; Ficht, Thomas A

    2013-01-01

    Brucella is the etiologic agent of brucellosis, one of the most common and widely distributed zoonotic diseases. Its highly infectious nature, the insidious, systemic, chronic, debilitating aspects of the disease and the lack of an approved vaccine for human use in the United States are features that make Brucella a viable threat to public health. One of the main impediments to vaccine development is identification of suitable antigens. In order to identify antigens that could potentially be used in a vaccine formulation, we describe a multi-step antigen selection approach. We initially used an algorithm (Vaxign) to predict ORF encoding outer membrane proteins with antigenic determinants. Differential gene expression during acute infection and published evidence for a role in virulence were used as criteria for down-selection of the candidate antigens that resulted from in silico prediction. This approach resulted in the identification of nine Brucella melitensis outer membrane proteins, 5 of which were recombinantly expressed and used for validation. Omp22 and Hia had the highest in silico scores for adhesin probability and also conferred invasive capacity to E. coli overexpressing recombinant proteins. With the exception of FlgK in the goat, all proteins reacted to pooled sera from exposed goats, mice, and humans. BtuB, Hia and FlgK stimulated a mixed Th1-Th2 response in splenocytes from immunized mice while BtuB and Hia elicited NO release from splenocytes of S19 immunized mice. The results support the applicability of the current approach to the identification of antigens with immunogenic and invasive properties. Studies to assess immunogenicity and protective efficacy of individual proteins in the mouse are currently underway.

  7. Genomic expression libraries for the identification of cross-reactive orthopoxvirus antigens.

    Directory of Open Access Journals (Sweden)

    Lilija Miller

    Full Text Available Increasing numbers of human cowpox virus infections that are being observed and that particularly affect young non-vaccinated persons have renewed interest in this zoonotic disease. Usually causing a self-limiting local infection, human cowpox can in fact be fatal for immunocompromised individuals. Conventional smallpox vaccination presumably protects an individual from infections with other Orthopoxviruses, including cowpox virus. However, available live vaccines are causing severe adverse reactions especially in individuals with impaired immunity. Because of a decrease in protective immunity against Orthopoxviruses and a coincident increase in the proportion of immunodeficient individuals in today's population, safer vaccines need to be developed. Recombinant subunit vaccines containing cross-reactive antigens are promising candidates, which avoid the application of infectious virus. However, subunit vaccines should contain carefully selected antigens to confer a solid cross-protection against different Orthopoxvirus species. Little is known about the cross-reactivity of antibodies elicited to cowpox virus proteins. Here, we first identified 21 immunogenic proteins of cowpox and vaccinia virus by serological screenings of genomic Orthopoxvirus expression libraries. Screenings were performed using sera from vaccinated humans and animals as well as clinical sera from patients and animals with a naturally acquired cowpox virus infection. We further analyzed the cross-reactivity of the identified immunogenic proteins. Out of 21 identified proteins 16 were found to be cross-reactive between cowpox and vaccinia virus. The presented findings provide important indications for the design of new-generation recombinant subunit vaccines.

  8. Simplest identification, O-specific polysaccharide purification and antigenic evaluation of Salmonella enterica serovar Typhi Vi negative isolate.

    Science.gov (United States)

    Salman, Muhammad; Ali, Aamir; Jabbar, Abdul; Sarwar, Yasra; Rahman, Moazur; Iqbal, Mazhar; Haque, Abdul

    2015-01-01

    Currently licensed typhoid vaccines are based on Vi capsular polysaccharides. Recent molecular reports from typhoid endemic countries state that Salmonella enterica serovar Typhi (S. Typhi) Vi negative strains occur naturally and cause typhoid fever which is indistinguishable from disease caused by Vi positive strains. Vaccine based on Vi polysaccharide may not protect patients if the invading S. Typhi are negative for Vi. The lipopolysaccharide (LPS) is an essential component of S. Typhi outer membrane in which O-specific polysaccharide (OSP) is a protective antigen and universal candidate for vaccine development. In this study, S. Typhi Vi negative isolates were discriminated from Vi positive isolates through a duplex PCR using primers of fliC-d (599bp) and tviA (495bp) genes. The LPS of S. Typhi Vi negative isolates was extracted by hot phenol method and OSP was purified by core hydrolysis. The yield of extracted LPS was 91 mg/L and that of purified OSP was 49.14 mg/L of culture broth. LPS showed ladder like appearance by zinc imidazole staining following SDS-PAGE. Whole cell challenged mice sera were used for in vitro antigenicity evaluation of the purified LPS and OSP. The antigenicity was found adequate by immunodiffusion assay. To our knowledge, this is the first report of purification and antigenic evaluation of LPS of a Vi negative S. Typhi isolate. The purified OSP from S. Typhi Vi negative isolate may be coupled with a carrier protein to produce universal low cost conjugate vaccine candidates for use in typhoid endemic regions.

  9. Immunoproteomic analysis of Brucella melitensis and identification of a new immunogenic candidate protein for the development of brucellosis subunit vaccine.

    Science.gov (United States)

    Yang, Yanling; Wang, Lin; Yin, Jigang; Wang, Xinglong; Cheng, Shipeng; Lang, Xulong; Wang, Xiuran; Qu, Hailong; Sun, Chunhui; Wang, Jinglong; Zhang, Rui

    2011-10-01

    In order to screen immunogenic candidate antigens for the development of a brucellosis subunit vaccine, an immunoproteomic assay was used to identify immunogenic proteins from Brucella melitensis 16 M soluble proteins. In this study, a total of 56 immunodominant proteins were identified from the two-dimensional electrophoresis immunoblot profiles by liquid chromatography tandem mass spectrometry (LC-MS/MS). Two proteins of interest, riboflavin synthase alpha chain (RS-α) and Loraine synthase (LS-2), which are both involved in riboflavin synthesis, were detected by two-dimensional immunoblots using antisera obtained from Brucella-infected human and goats. LS-2, however, is an already well-known vaccine candidate. Therefore, we focussed our studies on the novel vaccine candidate RS-α. B. melitensis RS-α and LS-2 were then expressed in Escherichia coli as fusion proteins with His tag. The humoral and cellular immune responses to the recombinant (r)RS-α was characterized. In response to in vitro stimulation by rRS-α, splenocytes from mice vaccinated with rRS-α were able to produce γ-interferon (IFN-γ) and interleukin (IL)-2 but not interleukin (IL)-4 and interleukin (IL)-10. Furthermore, rRS-α or rLS-2-vaccinated mice were partially protected against B. melitensis infection. Our results suggested that we have developed a high-throughout, accurate, rapid and highly efficient method for the identification of candidate antigens by a combination of immunoproteomics with immunisation and bacterial challenge and rRs-α could be a useful candidate for the development of subunit vaccines against B. melitensis.

  10. Expression and Antigenic Evaluation of VacA Antigenic Fragment of Helicobacter Pylori

    Directory of Open Access Journals (Sweden)

    Leila Hasanzadeh

    2013-07-01

    Full Text Available Objective(s: Helicobacter pylori, a human specific gastric pathogen is a causative agent of chronic active gastritis. The vacuolating cytotoxin (VacA is an effective virulence factor involved in gastric injury. The aim of this study was to construct a recombinant protein containing antigenic region of VacA gene and determine its antigenicity.   Materials and Methods: The antigenic region of VacA gene was detected by bioinformatics methods. The polymerase chain reaction method was used to amplify a highly antigenic region of VacA gene from chromosomal DNA of H. pylori. The eluted product was cloned into the prokaryotic expression vector pET32a. The target protein was expressed in the Escherichia coli BL21 (DE3 pLysS. The bacteria including pET32a-VacA plasmids were induced by IPTG. The antigenicity was finally studied by western blotting using sera of 15 H. pylori infected patients after purification. Results: Enzyme digestion analysis, PCR and DNA sequencing results showed that the target gene was inserted correctly into the recombinant vector. The expressed protein was purified successfully via affinity chromatography. Data indicated that antigenic region of VacA protein from Helicobacter pylori was recognized by all 15 patient’s sera. Conclusion : Our data showed that antigenic region of VacA protein can be expressed by in E. co.li. This protein was recognized by sera patients suffering from H. pylori infection. the recombinant protein has similar epitopes and close antigenic properties to the natural form of this antigen. Recombinant antigenic region of VacA protein also seems to be a promising antigen for protective and serologic diagnosis .

  11. A NEW SYNTHETIC FUNCTIONALIZED ANTIGEN CARRIER

    NARCIS (Netherlands)

    DRIJFHOUT, JW; BLOEMHOFF, W

    1991-01-01

    A new synthetic functionalized antigen carrier is described. It consists of a core of seven branched lysine residues, of which each of the four N-terminal lysine residues contains two N-(S-acetylmercaptoacetyl)-glutamyl residues. After removal of the protecting S-acetyl groups affording eight thiol

  12. Identification, characterization and antigenicity of the Plasmodium vivax rhoptry neck protein 1 (PvRON1

    Directory of Open Access Journals (Sweden)

    Patarroyo Manuel E

    2011-10-01

    the P. vivax rhoptry neck protein 1 in the VCG-1 strain. Taking into account that PvRON1 shares several important characteristics with other Plasmodium antigens that play a functional role during RBC invasion and, as shown here, it is antigenic, it could be considered as a good vaccine candidate. Further studies aimed at assessing its immunogenicity and protection-inducing ability in the Aotus monkey model are thus recommended.

  13. Biological role of surface Toxoplasma gondii antigen in development of vaccine

    Institute of Scientific and Technical Information of China (English)

    Ke-Yi Liu; Dian-Bo Zhang; Qing-Kuan Wei; Jin Li; Gui-Ping Li; Jin-Zhi Yu

    2006-01-01

    AIM: To analyze the biological role of the surface antigen of Toxoplasma gondii (T gondii) in development of vaccine.METHODS: The surface antigen of Tgondii (SAG1)was expressed in vitro. The immune response of the host to the antigen was investigated by detection of specific antibody reaction to SAG1 and production of cytokines. Mice were immunized with recombinant SAG1and challenged with lethal strain of T gondii RH. The monoclonal antibody to r-SAG1 was prepared and used to study the effects of SAG1 on T gondii tachyzoites under electromicroscope.RESULTS:The mice immunized with recombinant SAG1 delayed death for 60 h compared to the control group.The recombinant SAG1 induced specific high titer of IgG and IgM antibodies as well as IFN-γ, IL-2 and IL-4cytokines in mice. In contrast, IL-12, IL-6 and TNF-αwere undetectable. When T gondii tachyzoites were treated with the monoclonal antibody to r-SAG1, the parasites were gathered together, destroyed, deformed,swollen, and holes and gaps formed on the surface.CONCLUSION: SAG1 may be an excellent vaccine candidate against T gondii. The immune protection induced by SAG1 against Tgondii may be regulated by both hormone- and cell-mediated immune response.

  14. Towards Treating Chemistry Teacher Candidates as Human

    Science.gov (United States)

    Lewthwaite, Brian Ellis

    2008-05-01

    This research inquiry investigates the factors influencing chemistry teacher candidates’ development during their extended practica in the second and final year of an After-Degree Bachelor of Education at a university in central Canada. A variety of data sources are used to identify the risk and protective factors impeding and contributing to the achievement of their chemistry pedagogical aspirations. Two theoretical frameworks, both having their origins in the pioneering work of Kurt Lewin, are used to conceptualize how a complex amalgam of personal attribute and environmental factors and the interplay among these factors influence teacher candidate developmental trajectories. The tenets of both Bronfenbrenner’s bioecological model and Learning Environment research provide insights into how the factors influencing teacher candidate development can be understood and systematically documented to provide a template for reflective consideration of the practicum experience for both teacher candidates and those involved in fostering the development of chemistry teacher candidates.

  15. Eosinofil Sel Penyaji Antigen

    Directory of Open Access Journals (Sweden)

    Safari Wahyu Jatmiko

    2015-04-01

    Full Text Available Sel eosinofil merupakan jenis sel lekosit yang terlibat dalam berbagai patogenesis penyakit. Sel eosinofil pada awalnya dikenal sebagai sel efektor  dari sistem imunitas alamiah. Akan tetapi, kemampuan sel eosinofil dalam memfagositosis patogen menimbulkan dugaan bahwa sel eosinofil ikut berperan sebagai sel penyaji antigen. Hal ini dianalogikan dengan sel makrofag dan sel dendritik yang bisa memfagositosis dan menyajikan antigen sebagai hasil dari degradasi patogen yang difagositosis. Untuk menjawab permasalahan ini, penulis melakukan penelusuran artikel tentang eosinofil sebagai sel penyaji antigen melalui US National Library of Medicine National Institute of Healthdengan kata kunci eoshinophil dan antigen presenting cell. Hasil penelusuran adalah ditemukannya 10 artikel yang relevan dengan topik. Hasil dari sintesis kesepuluh jurnal tersebut adalah sel eosinofil mampu berperan sebagai sel penyaji antigen yang profesional (professionalantigenpresentng cell

  16. Towards Treating Chemistry Teacher Candidates as Human

    Science.gov (United States)

    Lewthwaite, Brian Ellis

    2008-01-01

    This research inquiry investigates the factors influencing chemistry teacher candidates' development during their extended practica in the second and final year of an After-Degree Bachelor of Education at a university in central Canada. A variety of data sources are used to identify the risk and protective factors impeding and contributing to the…

  17. What Is Known about the Immune Response Induced by Plasmodium vivax Malaria Vaccine Candidates?

    Science.gov (United States)

    López, Carolina; Yepes-Pérez, Yoelis; Hincapié-Escobar, Natalia; Díaz-Arévalo, Diana; Patarroyo, Manuel A.

    2017-01-01

    Malaria caused by Plasmodium vivax continues being one of the most important infectious diseases around the world; P. vivax is the second most prevalent species and has the greatest geographic distribution. Developing an effective antimalarial vaccine is considered a relevant control strategy in the search for means of preventing the disease. Studying parasite-expressed proteins, which are essential in host cell invasion, has led to identifying the regions recognized by individuals who are naturally exposed to infection. Furthermore, immunogenicity studies have revealed that such regions can trigger a robust immune response that can inhibit sporozoite (hepatic stage) or merozoite (erythrocyte stage) invasion of a host cell and induce protection. This review provides a synthesis of the most important studies to date concerning the antigenicity and immunogenicity of both synthetic peptide and recombinant protein candidates for a vaccine against malaria produced by P. vivax. PMID:28243235

  18. 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.

  19. 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.

  20. Systemic antibody responses to the immunodominant p23 antigen and p23 polymorphisms in children with cryptosporidiosis in Bangladesh.

    Science.gov (United States)

    Borad, Anoli J; Allison, Geneve M; Wang, David; Ahmed, Sabeena; Karim, Mohammad M; Kane, Anne V; Moy, Joy; Hibberd, Patricia L; Ajjampur, Sitara Swarna Rao; Kang, Gagandeep; Calderwood, Stephen B; Ryan, Edward T; Naumova, Elena; Khan, Wasif A; Ward, Honorine D

    2012-02-01

    Cryptosporidium is a major cause of diarrhea in children in developing countries. However, there is no vaccine available and little is known about immune responses to protective antigens. We investigated antibody responses to p23, a putative vaccine candidate, in children in Bangladesh with cryptosporidiosis and diarrhea (cases) and uninfected children with diarrhea (controls), and p23 gene polymorphisms in infecting species. Serum IgM, IgG, and IgA responses to p23 were significantly greater in cases than controls after three weeks of follow-up. Cases with acute diarrhea had significantly greater serum IgA and IgM responses than those with persistent diarrhea, which suggested an association with protection from prolonged disease. The p23 sequences were relatively conserved among infecting species and subtype families. Although most children were infected with Cryptosporidium hominis, there was a cross-reactive antibody response to C. parvum antigen. These results support further development of p23 as a vaccine candidate.

  1. Mapping antigenic motifs in the trypomastigote small surface antigen from Trypanosoma cruzi.

    Science.gov (United States)

    Balouz, Virginia; Cámara, María de Los Milagros; Cánepa, Gaspar E; Carmona, Santiago J; Volcovich, Romina; Gonzalez, Nicolás; Altcheh, Jaime; Agüero, Fernán; Buscaglia, Carlos A

    2015-03-01

    The trypomastigote small surface antigen (TSSA) is a mucin-like molecule from Trypanosoma cruzi, the etiological agent of Chagas disease, which displays amino acid polymorphisms in parasite isolates. TSSA expression is restricted to the surface of infective cell-derived trypomastigotes, where it functions as an adhesin and engages surface receptors on the host cell as a prerequisite for parasite internalization. Previous results have established TSSA-CL, the isoform encoded by the CL Brener clone, as an appealing candidate for use in serology-based diagnostics for Chagas disease. Here, we used a combination of peptide- and recombinant protein-based tools to map the antigenic structure of TSSA-CL at maximal resolution. Our results indicate the presence of different partially overlapping B-cell epitopes clustering in the central portion of TSSA-CL, which contains most of the polymorphisms found in parasite isolates. Based on these results, we assessed the serodiagnostic performance of a 21-amino-acid-long peptide that spans TSSA-CL major antigenic determinants, which was similar to the performance of the previously validated glutathione S-transferase (GST)-TSSA-CL fusion molecule. Furthermore, the tools developed for the antigenic characterization of the TSSA antigen were also used to explore other potential diagnostic applications of the anti-TSSA humoral response in Chagasic patients. Overall, our present results provide additional insights into the antigenic structure of TSSA-CL and support this molecule as an excellent target for molecular intervention in Chagas disease.

  2. 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.

  3. 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

  4. 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.

  5. Proteomic characterization of Helicobacter pylori CagA antigen recognized by child serum antibodies and its epitope mapping by peptide array.

    Directory of Open Access Journals (Sweden)

    Junko Akada

    Full Text Available Serum antibodies against pathogenic bacteria play immunologically protective roles, and can be utilized as diagnostic markers of infection. This study focused on Japanese child serum antibodies against Helicobacter pylori, a chronically-infected gastric bacterium which causes gastric cancer in adults. Serological diagnosis for H. pylori infection is well established for adults, but it needs to be improved for children. Serum samples from 24 children, 22 H. pylori (Hp-positive and 2 Hp-negative children, were used to catalogue antigenic proteins of a Japanese strain CPY2052 by two-dimensional electrophoresis followed by immunoblot and LC-MS/MS analysis. In total, 24 proteins were identified as candidate antigen proteins. Among these, the major virulence factor, cytotoxin-associated gene A protein (CagA was the most reactive antigen recognized by all the Hp-positive sera even from children under the age of 3 years. The major antigenic part of CagA was identified in the middle region, and two peptides containing CagA epitopes were identified using a newly developed peptide/protein-combined array chip method, modified from our previous protein chip method. Each of the epitopes was found to contain amino acid residue(s unique to East Asian CagA. Epitope analysis of CagA indicated importance of the regional CagA antigens for serodiagnosis of H. pylori infection in children.

  6. Complex Antigens Drive Permissive Clonal Selection in Germinal Centers.

    Science.gov (United States)

    Kuraoka, Masayuki; Schmidt, Aaron G; Nojima, Takuya; Feng, Feng; Watanabe, Akiko; Kitamura, Daisuke; Harrison, Stephen C; Kepler, Thomas B; Kelsoe, Garnett

    2016-03-15

    Germinal center (GC) B cells evolve toward increased affinity by a Darwinian process that has been studied primarily in genetically restricted, hapten-specific responses. We explored the population dynamics of genetically diverse GC responses to two complex antigens-Bacillus anthracis protective antigen and influenza hemagglutinin-in which B cells competed both intra- and interclonally for distinct epitopes. Preferred VH rearrangements among antigen-binding, naive B cells were similarly abundant in early GCs but, unlike responses to haptens, clonal diversity increased in GC B cells as early "winners" were replaced by rarer, high-affinity clones. Despite affinity maturation, inter- and intraclonal avidities varied greatly, and half of GC B cells did not bind the immunogen but nonetheless exhibited biased VH use, V(D)J mutation, and clonal expansion comparable to antigen-binding cells. GC reactions to complex antigens permit a range of specificities and affinities, with potential advantages for broad protection.

  7. 肿瘤相关抗原HSC70在食管癌中的鉴定与表达研究%The identification and expression study of HSC70 as a candidate of tumor associated antigen in esophageal squamous cell carcinoma

    Institute of Scientific and Technical Information of China (English)

    高红军; 岳志刚; 周艳秋; 许慧; 段志玲; 郑朝旭

    2012-01-01

    目的 探索食管鳞状细胞癌的肿瘤相关抗原.方法 提取食管鳞状细胞癌组织蛋白,用20例食管癌患者血清和20例健康对照血清分别作为检测抗体进行Western blot分析,比较分析二者的差异,将差异蛋白酶解后用质谱进行鉴定分析;用免疫组化方法对鉴定的肿瘤相关抗原进行验证.结果 食管癌血清的阳性信号比较多,其中70kDa的蛋白阳性率为40%(8/20),而健康对照血清阳性率为0%(0/20),该蛋白被鉴定为HSC70或称HSPA8.免疫组化结果显示HSC70在食管癌组织主要表达于细胞浆和细胞核,且表达明显高于癌旁正常组织.结论 联合免疫印记和质谱技术可以鉴定肿瘤相关抗原;HSC70可能是食管癌发生的重要参与蛋白,可能是食管癌诊断和治疗的关键靶分子.%Objective To identify novel tumor associated antigens( TAA )in esophageal squamous cell carcinoma( ESCC ). Methods The proteins extracted from tissues of ESCC were separated by two dimensional polyacrylamide gel electrophoresis, and followed by Western blot analysis in which sera from 20 patients with ESCC and 20 healthy controls were tested for primary antibodies. Positive spots were excised from Coomassie blue -stained gels and the tryptic peptides were analyzed by matrix - assisted laser disorption/ionization time - of - flight mass spectrometry( MALDI - TOF - MS ). The expression of the candidate TAA in ESCC tissue was detected by immunohistochemical staining( IHC ). Results Sera from patients with ESCC yielded multiple spots,one of which was identified as heat shock 70 kDa protein 8( HSC70 or HSPA8 )by MALDI - TOF - MS. The immuno-histochemistry analysis showed that HSC70 was located in both cytoplasm and nucleus, and had a higher expression in cancer tissues than paracarcinoma normal tissue. Conclusion The combination of immunoblot and mass spectrometry may identify some novel TAAs. These results suggested that HSC70 may play a role in tumorigenesis of

  8. Cross-protective immunity against multiple influenza virus subtypes by a novel modified vaccinia Ankara (MVA) vectored vaccine in mice.

    Science.gov (United States)

    Brewoo, Joseph N; Powell, Tim D; Jones, Jeremy C; Gundlach, Nancy A; Young, Ginger R; Chu, Haiyan; Das, Subash C; Partidos, Charalambos D; Stinchcomb, Dan T; Osorio, Jorge E

    2013-04-03

    Development of an influenza vaccine that provides cross-protective immunity remains a challenge. Candidate vaccines based on a recombinant modified vaccinia Ankara (MVA) viral vector expressing antigens from influenza (MVA/Flu) viruses were constructed. A vaccine candidate, designated MVA/HA1/C13L/NP, that expresses the hemagglutinin from pandemic H1N1 (A/California/04/09) and the nucleoprotein (NP) from highly pathogenic H5N1 (A/Vietnam/1203/04) fused to a secretory signal sequence from vaccinia virus was highly protective. The vaccine elicited strong antibody titers to homologous H1N1 viruses while cross-reactive antibodies to heterologous viruses were not detectable. In mice, this MVA/HA1/C13L/NP vaccine conferred complete protection against lethal challenge with A/Vietnam/1203/04 (H5N1), A/Norway/3487-2/09 (pandemic H1N1) or A/Influenza/Puerto Rico/8/34 (seasonal H1N1) and partial protection (57.1%) against challenge with seasonal H3N2 virus (A/Aichi/68). The protective efficacy of the vaccine was not affected by pre-existing immunity to vaccinia. Our findings highlight MVA as suitable vector to express multiple influenza antigens that could afford broad cross-protective immunity against multiple subtypes of influenza virus.

  9. Preclinical evaluation of a chemically detoxified pneumolysin as pneumococcal vaccine antigen

    Science.gov (United States)

    Hermand, Philippe; Vandercammen, Annick; Mertens, Emmanuel; Di Paolo, Emmanuel; Verlant, Vincent; Denoël, Philippe; Godfroid, Fabrice

    2017-01-01

    ABSTRACT The use of protein antigens able to protect against the majority of Streptococcus pneumoniae serotypes is envisaged as stand-alone and/or complement to the current capsular polysaccharide-based pneumococcal vaccines. Pneumolysin (Ply) is a key virulence factor that is highly conserved in amino acid sesec-typsecquence across pneumococcal serotypes, and therefore may be considered as a vaccine target. However, native Ply cannot be used in vaccines due to its intrinsic cytolytic activity. In the present work a completely, irreversibly detoxified pneumolysin (dPly) has been generated using an optimized formaldehyde treatment. Detoxi-fication was confirmed by dPly challenge in mice and histological analysis of the injection site in rats. Immunization with dPly elicited Ply-specific functional antibodies that were able to inhibit Ply activity in a hemolysis assay. In addition, immunization with dPly protected mice against lethal intranasal challenge with Ply, and intranasal immunization inhibited nasopharyngeal colonization after intranasal challenge with homologous or heterologous pneumococcal strain. Our findings supported dPly as a valid candidate antigen for further pneumococcal vaccine development. PMID:27768518

  10. Montanide™ ISA 71 VG adjuvant enhances antibody and cell-mediated immune responses to profilin subunit antigen vaccination and promotes protection against Eimeria acervulina and Eimeria tenella. Experimental Parasitology

    Science.gov (United States)

    The present study was conducted to investigate the immunoenhancing effects of MontanideTM ISA 71 VG adjuvant on profilin subunit antigen vaccination. Broiler chickens were immunized subcutaneously with a purified Eimeria acervulina recombinant profilin protein, either alone or mixed with ISA 71 VG, ...

  11. 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....

  12. Do FY antigens act as minor histocompatibility antigens in the graft-versus-host disease paradigm after human leukocyte antigen-identical sibling hematopoietic stem cell transplantation?

    Science.gov (United States)

    Sellami, Mohamed Hichem; Chaabane, Manel; Kaabi, Houda; Torjemane, Lamia; Ladeb, Saloua; Ben Othmane, Tarek; Hmida, Slama

    2012-03-01

    FY antigens are candidate minor histocompatibility antigens relevant to renal allograft rejection, but no data have been reported about their role in graft-versus-host disease (GVHD) incidence after human leukocyte antigen (HLA)-identical siblings hematopoietic stem cell transplantation (HSCT). The aim of this study was to examine the effect of donor/recipient disparity at FY antigens on the incidence of GVHD in Tunisian patients receiving an HLA-identical HSCT. This work enrolled 105 Tunisian pairs of recipients and their HLA-identical sibling donors of HSCs. FY genotyping was performed with the polymerase chain reaction-sequence-specific primer method and donor/recipient disparity for these antigens was analyzed at two levels: incompatibility and nonidentity. The case-control analyses showed no significant correlation between FY disparity and the incidence of either acute or chronic GVHD. Sample size calculation showed that 572 cases and 1716 controls would be necessary to be able to detect a significant association with 80% power and two-sided type I error level of 5% (α=0.05). The lack of association in the studied cohort may be explained by the low immunogenicity of FY antigens in HSCT context, compared with other antigens such as HA-1 and CD31.

  13. Monospecific antibody against Bordetella pertussis Adenylate Cyclase protects from Pertussis

    Directory of Open Access Journals (Sweden)

    Yasmeen Faiz Kazi

    2012-06-01

    Full Text Available Objectives: Acellular pertussis vaccines has been largely accepted world-wide however, there are reports about limitedantibody response against these vaccines suggesting that multiple antigens should be included in acellular vaccinesto attain full protection. The aim of present study was to evaluate the role of Bordetella pertussis adenylate cyclase as aprotective antigen.Materials and methods: Highly mono-specific antibody against adenylate cyclase (AC was raised in rabbits usingnitrocellulose bound adenylate cyclase and the specificity was assessed by immuoblotting. B.pertussis 18-323, wasincubated with the mono-specific serum and without serum as a control. Mice were challenged intra-nasally and pathophysiolgicalresponses were recorded.Results: The production of B.pertussis adenylate cyclase monospecific antibody that successfully recognized on immunoblotand gave protection against fatality (p< 0.01 and lung consolidation (p <0.01. Mouse weight gain showedsignificant difference (p< 0.05.Conclusion: These preliminary results highlight the role of the B.pertussis adenylate cyclase as a potential pertussisvaccine candidate. B.pertussis AC exhibited significant protection against pertussis in murine model. J Microbiol InfectDis 2012; 2(2: 36-43Key words: Pertussis; monospecific; antibody; passive-protection

  14. Primary and Presidential Candidates

    DEFF Research Database (Denmark)

    Goddard, Joseph

    2012-01-01

    This article looks at primary and presidential candidates in 2008 and 2012. Evidence suggests that voters are less influenced by candidates’ color, gender, or religious observation than previously. Conversely, markers of difference remain salient in the imaginations of pollsters and journalists...

  15. Plasmodium vivax antigen discovery based on alpha-helical coiled coil protein motif.

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    Nora Céspedes

    Full Text Available Protein α-helical coiled coil structures that elicit antibody responses, which block critical functions of medically important microorganisms, represent a means for vaccine development. By using bioinformatics algorithms, a total of 50 antigens with α-helical coiled coil motifs orthologous to Plasmodium falciparum were identified in the P. vivax genome. The peptides identified in silico were chemically synthesized; circular dichroism studies indicated partial or high α-helical content. Antigenicity was evaluated using human sera samples from malaria-endemic areas of Colombia and Papua New Guinea. Eight of these fragments were selected and used to assess immunogenicity in BALB/c mice. ELISA assays indicated strong reactivity of serum samples from individuals residing in malaria-endemic regions and sera of immunized mice, with the α-helical coiled coil structures. In addition, ex vivo production of IFN-γ by murine mononuclear cells confirmed the immunogenicity of these structures and the presence of T-cell epitopes in the peptide sequences. Moreover, sera of mice immunized with four of the eight antigens recognized native proteins on blood-stage P. vivax parasites, and antigenic cross-reactivity with three of the peptides was observed when reacted with both the P. falciparum orthologous fragments and whole parasites. Results here point to the α-helical coiled coil peptides as possible P. vivax malaria vaccine candidates as were observed for P. falciparum. Fragments selected here warrant further study in humans and non-human primate models to assess their protective efficacy as single components or assembled as hybrid linear epitopes.

  16. Screening and Primary Characterization of New Antigen Genes of Schistosoma Japonicum

    Institute of Scientific and Technical Information of China (English)

    王敏; 易新元; 李先平; 曾宪芳; 章洁

    2004-01-01

    To find Schistosoma japonicum(S.j) new antigen gene thus provide more useful vaccine candidates, the cDNA library of S. j adult worm was screened with sera of rabbits immtmized with the membrane antigens of Schistosoma japonicum hepato-portal schistosomula (SjHmAg). The positive clones were amplified by PCR and sequenced, then the sequences of clones were compared with all sequences in GenBank database using Blast process. The new clones were submitted to GenBank for accession numbers. Fifteen positive clones were obtained after three rounds of i mmunoscreening. The size of S. j cDNA fragments in positive clones ranged from 0.7 kb-3.0 kb after automatically excised with the helper phage. Sequence analysis revealed that partial sequence of clone M5 had significant homology with S.j mitochondria rnRNA, the other positive clones were new S.j genes. M2 clone sequence (GenBank accession number AF502579) was 730 bp long it had a 117 bp open reading frame (ORF). The sequence of M15 (GenBank accession number AF502582) has no transmembrane region and encodes 92 amino acids, and its protein contains a ferredoxins iron-sulfur binding region signature and two VWFC signal regions. The size of M1 ,M8, M9, M12( GenBank accession numbers: AF502578, AF502580, AF500622, AF502581 ) ranges from 402 bp to 766 bp. It concluded that the sera from rabbit immunized with SjHmAg could recognize S. j specific antigens molecules, and these antigens may induce the protective immunity against S.j infection.

  17. 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.

  18. Conformational dynamics and antigenicity in the disordered malaria antigen merozoite surface protein 2.

    Directory of Open Access Journals (Sweden)

    Christopher A MacRaild

    Full Text Available Merozoite surface protein 2 (MSP2 of Plasmodium falciparum is an abundant, intrinsically disordered protein that is GPI-anchored to the surface of the invasive blood stage of the malaria parasite. Recombinant MSP2 has been trialled as a component of a malaria vaccine, and is one of several disordered proteins that are candidates for inclusion in vaccines for malaria and other diseases. Nonetheless, little is known about the implications of protein disorder for the development of an effective antibody response. We have therefore undertaken a detailed analysis of the conformational dynamics of the two allelic forms of MSP2 (3D7 and FC27 using NMR spectroscopy. Chemical shifts and NMR relaxation data indicate that conformational and dynamic properties of the N- and C-terminal conserved regions in the two forms of MSP2 are essentially identical, but significant variation exists between and within the central variable regions. We observe a strong relationship between the conformational dynamics and the antigenicity of MSP2, as assessed with antisera to recombinant MSP2. Regions of increased conformational order in MSP2, including those in the conserved regions, are more strongly antigenic, while the most flexible regions are minimally antigenic. This suggests that modifications that increase conformational order may offer a means to tune the antigenicity of MSP2 and other disordered antigens, with implications for vaccine design.

  19. Conformational Dynamics and Antigenicity in the Disordered Malaria Antigen Merozoite Surface Protein 2

    Science.gov (United States)

    Andrew, Dean; Krishnarjuna, Bankala; Nováček, Jiří; Žídek, Lukáš; Sklenář, Vladimír; Richards, Jack S.; Beeson, James G.; Anders, Robin F.; Norton, Raymond S.

    2015-01-01

    Merozoite surface protein 2 (MSP2) of Plasmodium falciparum is an abundant, intrinsically disordered protein that is GPI-anchored to the surface of the invasive blood stage of the malaria parasite. Recombinant MSP2 has been trialled as a component of a malaria vaccine, and is one of several disordered proteins that are candidates for inclusion in vaccines for malaria and other diseases. Nonetheless, little is known about the implications of protein disorder for the development of an effective antibody response. We have therefore undertaken a detailed analysis of the conformational dynamics of the two allelic forms of MSP2 (3D7 and FC27) using NMR spectroscopy. Chemical shifts and NMR relaxation data indicate that conformational and dynamic properties of the N- and C-terminal conserved regions in the two forms of MSP2 are essentially identical, but significant variation exists between and within the central variable regions. We observe a strong relationship between the conformational dynamics and the antigenicity of MSP2, as assessed with antisera to recombinant MSP2. Regions of increased conformational order in MSP2, including those in the conserved regions, are more strongly antigenic, while the most flexible regions are minimally antigenic. This suggests that modifications that increase conformational order may offer a means to tune the antigenicity of MSP2 and other disordered antigens, with implications for vaccine design. PMID:25742002

  20. Boosting BCG-primed mice with chimeric DNA vaccine HG856A induces potent multifunctional T cell responses and enhanced protection against Mycobacterium tuberculosis.

    Science.gov (United States)

    Ji, Ping; Hu, Zhi-Dong; Kang, Han; Yuan, Qin; Ma, Hui; Wen, Han-Li; Wu, Juan; Li, Zhong-Ming; Lowrie, Douglas B; Fan, Xiao-Yong

    2016-02-01

    The tuberculosis pandemic continues to rampage despite widespread use of the current Bacillus Calmette-Guerin (BCG) vaccine. Because DNA vaccines can elicit effective antigen-specific immune responses, including potent T cell-mediated immunity, they are promising vehicles for antigen delivery. In a prime-boost approach, they can supplement the inadequate anti-TB immunological memory induced by BCG. Based on this, a chimeric DNA vaccine HG856A encoding Mycobacterium tuberculosis (M. tuberculosis) immunodominant antigen Ag85A plus two copies of ESAT-6 was constructed. Potent humoral immune responses, as well as therapeutic effects induced by this DNA vaccine, were observed previously in M. tuberculosis-infected mice. In this study, we further evaluated the antigen-specific T cell immune responses and showed that repeated immunization with HG856A gave modest protection against M. tuberculosis challenge infection and significantly boosted the immune protection primed by BCG vaccination. Enhanced protection was accompanied by increased multifunctional Th1 CD4(+) T cell responses, most notably by an elevated frequency of M. tuberculosis antigen-specific IL-2-producing CD4(+) T cells post-vaccination. These data confirm the potential of chimeric DNA vaccine HG856A as an anti-TB vaccine candidate.

  1. Proteins of Leishmania (Viannia shawi confer protection associated with Th1 immune response and memory generation

    Directory of Open Access Journals (Sweden)

    Passero Luiz Felipe D

    2012-03-01

    Full Text Available Abstract Background Leishmania (Viannia shawi parasite was first characterized in 1989. Recently the protective effects of soluble leishmanial antigen (SLA from L. (V. shawi promastigotes were demonstrated using BALB/c mice, the susceptibility model for this parasite. In order to identify protective fractions, SLA was fractionated by reverse phase HPLC and five antigenic fractions were obtained. Methods F1 fraction was purified from L. (V. shawi parasite extract by reverse phase HPLC. BALB/c mice were immunized once a week for two consecutive weeks by subcutaneous routes in the rump, using 25 μg of F1. After 1 and 16 weeks of last immunization, groups were challenged in the footpad with L. (V. shawi promastigotes. After 2 months, those same mice were sacrificed and parasite burden, cellular and humoral immune responses were evaluated. Results The F1 fraction induced a high degree of protection associated with an increase in IFN-γ, a decrease in IL-4, increased cell proliferation and activation of CD8+T lymphocytes. Long-term protection was acquired in F1-immunized mice, associated with increased CD4+ central memory T lymphocytes and activation of both CD4+ and CD8+ T cells. In addition, F1-immunized groups showed an increase in IgG2a levels. Conclusions The inductor capability of antigens to generate memory lymphocytes that can proliferate and secrete beneficial cytokines upon infection could be an important factor in the development of vaccine candidates against American Tegumentary Leishmaniasis.

  2. Pilot Candidate Selection

    Science.gov (United States)

    1989-05-01

    pilot selection system and to best support up-front track selection for SUPT? Assumptions The USAF Trainer Masterplan does not include a plan to...replace the T-41 with a new flight screening aircraft. In addition, the Masterplan states that candidates will be track selected prior to entry into primary...training. (3:10) While the Masterplan is not a static document and aircraft procurement plans and/or the timing of track selection are subject to

  3. Immunogenicity and protective efficacy of DMT liposome-adjuvanted tuberculosis subunit CTT3H vaccine.

    Science.gov (United States)

    Teng, Xindong; Tian, Maopeng; Li, Jianrong; Tan, Songwei; Yuan, Xuefeng; Yu, Qi; Jing, Yukai; Zhang, Zhiping; Yue, Tingting; Zhou, Lei; Fan, Xionglin

    2015-01-01

    Different strategies have been proposed for the development of protein subunit vaccine candidates for tuberculosis (TB), which shows better safety than other types of candidates and the currently used Bacillus Calmette-Guérin (BCG) vaccine. In order to develop more effective protein subunits depending on the mechanism of cell-mediated immunity against TB, a polyprotein CTT3H, based on 5 immunodominant antigens (CFP10, TB10.4, TB8.4, Rv3615c, and HBHA) with CD8(+) epitopes of Mycobacterium tuberculosis, was constructed in this study. We vaccinated C57BL/6 mice with a TB subunit CTT3H protein in an adjuvant of dimethyldioctadecylammonium/monophosphoryl lipid A/trehalose 6,6'-dibehenate (DDA/MPL/TDB, DMT) liposome to investigate the immunogenicity and protective efficacy of this novel vaccine. Our results demonstrated that DMT liposome-adjuvanted CTT3H vaccine not only induced an antigen-specific CD4(+) Th1 response, but also raised the number of PPD- and CTT3H-specific IFN-γ(+) CD8(+) T cells and elicited strong CTL responses against TB10.4, which provided more effective protection against a 60 CFU M. tuberculosis aerosol challenge than PBS control and DMT adjuvant alone. Our findings indicate that DMT-liposome is an effective adjuvant to stimulate CD8(+) T cell responses and the DMT-adjuvanted subunit CTT3H vaccine is a promising candidate for the next generation of TB vaccine.

  4. Immunogenicity of HSP-70, KMP-11 and PFR-2 leishmanial antigens in the experimental model of canine visceral leishmaniasis.

    Science.gov (United States)

    Carrillo, Eugenia; Crusat, Martín; Nieto, Javier; Chicharro, Carmen; Thomas, Maria del Carmen; Martínez, Enrique; Valladares, Basilio; Cañavate, Carmen; Requena, Jose María; López, Manuel Carlos; Alvar, Jorge; Moreno, Javier

    2008-03-28

    Zoonotic visceral leishmaniasis (ZVL) is a parasitic disease caused by Leishmania infantum/L. chagasi that is emerging as an important medical and veterinary problem. Dogs are the domestic reservoir for this parasite and, therefore, the main target for controlling the transmission to humans. In the present work, we have evaluated the immunogenicity of the Leishmania infantum heat shock protein (HSP)-70, paraflagellar rod protein (PFR)-2 and kinetoplastida membrane protein (KMP)-11 recombinant proteins in dogs experimentally infected with the parasite. We have shown that peripheral blood mononuclear cells (PBMC) from experimentally infected dogs proliferated in response to these recombinant antigens and against the soluble leishmanial antigen (SLA). We have also quantified the mRNA expression level of the cytokines induced in PBMC upon stimulation with the HSP-70, PFR-2 and KMP-11 proteins. These recombinant proteins induced an up-regulation of IFN-gamma. HSP-70 and PFR-2 also produced an increase of the TNF-alpha transcripts abundance. No measurable induction of IL-10 was observed and low levels of IL-4 mRNA were produced in response to the three mentioned recombinant antigens. Serum levels of specific antibodies against HSP-70, PFR-2 and KMP-11 recombinant proteins were also determined in these animals. Our study showed that HSP-70, KMP-11 and PFR-2 proteins are recognized by infected canines. Furthermore, these antigens produce a Th1-type immune response, suggesting that they may be involved in protection. The identification as vaccine candidates of Leishmania antigens that elicit appropriate immune responses in the canine model is a key step in the rational approach to generate a vaccine for canine visceral leishmaniasis.

  5. Proteomics-identified Bvg-activated autotransporters protect against bordetella pertussis in a mouse model.

    Science.gov (United States)

    de Gouw, Daan; Gouw, Daan de; de Jonge, Marien I; Jonge, Marien I de; Hermans, Peter W M; Wessels, Hans J C T; Zomer, Aldert; Berends, Alinda; Pratt, Catherine; Berbers, Guy A; Mooi, Frits R; Diavatopoulos, Dimitri A

    2014-01-01

    Pertussis is a highly infectious respiratory disease of humans caused by the bacterium Bordetella pertussis. Despite high vaccination coverage, pertussis has re-emerged globally. Causes for the re-emergence of pertussis include limited duration of protection conferred by acellular pertussis vaccines (aP) and pathogen adaptation. Pathogen adaptations involve antigenic divergence with vaccine strains, the emergence of strains which show enhanced in vitro expression of a number of virulence-associated genes and of strains that do not express pertactin, an important aP component. Clearly, the identification of more effective B. pertussis vaccine antigens is of utmost importance. To identify novel antigens, we used proteomics to identify B. pertussis proteins regulated by the master virulence regulatory system BvgAS in vitro. Five candidates proteins were selected and it was confirmed that they were also expressed in the lungs of naïve mice seven days after infection. The five proteins were expressed in recombinant form, adjuvanted with alum and used to immunize mice as stand-alone antigens. Subsequent respiratory challenge showed that immunization with the autotransporters Vag8 and SphB1 significantly reduced bacterial load in the lungs. Whilst these antigens induced strong opsonizing antibody responses, we found that none of the tested alum-adjuvanted vaccines - including a three-component aP - reduced bacterial load in the nasopharynx, suggesting that alternative immunological responses may be required for efficient bacterial clearance from the nasopharynx.

  6. Role of 4-1BB receptor in the control played by CD8(+ T cells on IFN-gamma production by Mycobacterium tuberculosis antigen-specific CD4(+ T Cells.

    Directory of Open Access Journals (Sweden)

    Carla Palma

    Full Text Available BACKGROUND: Antigen-specific IFN-gamma producing CD4(+ T cells are the main mediators of protection against Mycobacterium tuberculosis infection both under natural conditions and following vaccination. However these cells are responsible for lung damage and poor vaccine efficacy when not tightly controlled. Discovering new tools to control nonprotective antigen-specific IFN-gamma production without affecting protective IFN-gamma is a challenge in tuberculosis research. METHODS AND FINDINGS: Immunization with DNA encoding Ag85B, a candidate vaccine antigen of Mycobacterium tuberculosis, elicited in mice a low but protective CD4(+ T cell-mediated IFN-gamma response, while in mice primed with DNA and boosted with Ag85B protein a massive increase in IFN-gamma response was associated with loss of protection. Both protective and non-protective Ag85B-immunization generated antigen-specific CD8(+ T cells which suppressed IFN-gamma-secreting CD4(+ T cells. However, ex vivo ligation of 4-1BB, a member of TNF-receptor super-family, reduced the massive, non-protective IFN-gamma responses by CD4(+ T cells in protein-boosted mice without affecting the low protective IFN-gamma-secretion in mice immunized with DNA. This selective inhibition was due to the induction of 4-1BB exclusively on CD8(+ T cells of DNA-primed and protein-boosted mice following Ag85B protein stimulation. The 4-1BB-mediated IFN-gamma inhibition did not require soluble IL-10, TGF-beta, XCL-1 and MIP-1beta. In vivo Ag85B stimulation induced 4-1BB expression on CD8(+ T cells and in vivo 4-1BB ligation reduced the activation, IFN-gamma production and expansion of Ag85B-specific CD4(+ T cells of DNA-primed and protein-boosted mice. CONCLUSION/SIGNIFICANCE: Antigen-specific suppressor CD8(+ T cells are elicited through immunization with the mycobacterial antigen Ag85B. Ligation of 4-1BB receptor further enhanced their suppressive activity on IFN-gamma-secreting CD4(+ T cells. The selective

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

    Directory of Open Access Journals (Sweden)

    Felipe Romero-Saavedra

    Full Text Available 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

  8. Contaminant Candidate List 3

    Data.gov (United States)

    U.S. Environmental Protection Agency — CCL 3 is a list of contaminants that are currently not subject to any proposed or promulgated national primary drinking water regulations, that are known or...

  9. Contaminant Candidate List 1

    Data.gov (United States)

    U.S. Environmental Protection Agency — CCL 1 is a list of contaminants that are currently not subject to any proposed or promulgated national primary drinking water regulations, that are known or...

  10. Contaminant Candidate List 2

    Data.gov (United States)

    U.S. Environmental Protection Agency — CCL 2 is a list of contaminants that are currently not subject to any proposed or promulgated national primary drinking water regulations, that are known or...

  11. Overlapping antigenic repertoires of variant antigens expressed on the surface of erythrocytes infected by Plasmodium falciparum

    DEFF Research Database (Denmark)

    Giha, H A; Staalsoe, T; Dodoo, D;

    1999-01-01

    Antibodies against variable antigens expressed on the surface of Plasmodium falciparum-infected erythrocytes are believed to be important for protection against malaria. A target for these antibodies is the P. falciparum erythrocyte membrane protein 1, PfEMP1, which is encoded by around 50 var...... genes and undergoes clonal variation. Using agglutination and mixed agglutination tests and flow cytometry to analyse the recognition of variant antigens on parasitized erythrocytes by plasma antibodies from individuals living in Daraweesh in eastern Sudan, an area of seasonal and unstable malaria...

  12. An alphavirus vector-based tetravalent dengue vaccine induces a rapid and protective immune response in macaques that differs qualitatively from immunity induced by live virus infection.

    Science.gov (United States)

    White, Laura J; Sariol, Carlos A; Mattocks, Melissa D; Wahala M P B, Wahala; Yingsiwaphat, Vorraphun; Collier, Martha L; Whitley, Jill; Mikkelsen, Rochelle; Rodriguez, Idia V; Martinez, Melween I; de Silva, Aravinda; Johnston, Robert E

    2013-03-01

    Despite many years of research, a dengue vaccine is not available, and the more advanced live attenuated vaccine candidate in clinical trials requires multiple immunizations with long interdose periods and provides low protective efficacy. Here, we report important contributions to the development of a second-generation dengue vaccine. First, we demonstrate that a nonpropagating vaccine vector based on Venezuelan equine encephalitis virus replicon particles (VRP) expressing two configurations of dengue virus E antigen (subviral particles [prME] and soluble E dimers [E85]) successfully immunized and protected macaques against dengue virus, while antivector antibodies did not interfere with a booster immunization. Second, compared to prME-VRP, E85-VRP induced neutralizing antibodies faster, to higher titers, and with improved protective efficacy. Third, this study is the first to map antigenic domains and specificities targeted by vaccination versus natural infection, revealing that, unlike prME-VRP and live virus, E85-VRP induced only serotype-specific antibodies, which predominantly targeted EDIII, suggesting a protective mechanism different from that induced by live virus and possibly live attenuated vaccines. Fourth, a tetravalent E85-VRP dengue vaccine induced a simultaneous and protective response to all 4 serotypes after 2 doses given 6 weeks apart. Balanced responses and protection in macaques provided further support for exploring the immunogenicity and safety of this vaccine candidate in humans.

  13. Conservation of Meningococcal Antigens in the Genus Neisseria

    OpenAIRE

    Muzzi, Alessandro; Mora, Marirosa; Pizza, Mariagrazia; Rappuoli, Rino; Donati, Claudio

    2013-01-01

    ABSTRACT Neisseria meningitidis, one of the major causes of bacterial meningitis and sepsis, is a member of the genus Neisseria, which includes species that colonize the mucosae of many animals. Three meningococcal proteins, factor H-binding protein (fHbp), neisserial heparin-binding antigen (NHBA), and N. meningitidis adhesin A (NadA), have been described as antigens protective against N. meningitidis of serogroup B, and they have been employed as vaccine components in preclinical and clinic...

  14. Candidate Multi-Peptide-Vaccine Against Classical Swine Fever Virus Induces Strong Antibody Response with Predefined Specificity

    Institute of Scientific and Technical Information of China (English)

    张耿; 董晓楠; 陈应华

    2002-01-01

    Previous investigations demonstrated that the envelope glycoprotein E2 (gp55) of classical swine fever virus (CSFV) is the most immunogenic protein. Interestingly, recombinant protein E2 that contains only one structural antigenic unit (unit B/C or A) could protect pigs from a lethal challenge of CSFV. Based on these findings, we designed and prepared five overlapping synthetic peptides that covered the sequence unit B/C (aa 693-777) of Shimen E2 and conjugated individual peptides with bovine serum albumin (BSA). After the vaccination, the specificity of the rabbit sera was analyzed in the enzyme-linked immunosorbent assay (ELISA) and the fast protein liquid chromatography (FPLC). The results show that each of the five candidate peptide-vaccines can successfully induce a high titer of specific antibodies in New Zealand White Rabbits (n=3). Subsequently, the five candidate peptide-vaccines were applied in combination for immunization of pigs (n=10) and induced specific and strong humoral responses against all of the five designed peptides in pigs. Our studies indicate that the candidate multi-peptide-vaccine would prove an excellent marker vaccine against CSFV and provide a model for developing effective synthetic peptide vaccines to stop viral epidemics in humans and animals.

  15. Detection of Fasciola hepatica and Fasciola gigantica common and uncommon antigens, using rabbit hyper immune serum raised against their excretory-secretory and somatic antigens.

    Science.gov (United States)

    Abdolahi Khabisi, S; Sarkari, B

    2016-12-01

    Fasciolosis is an important neglected helminth disease caused by two liver flukes, Fasciola hepatica and Fasciola gigantica. The two species of Fasciola are usually different in their morphological and molecular features. They have also common and uncommon antigens in both their somatic and excretory secretory metabolites. In this study, we compared somatic and excretory-secretory (ES) antigens of F. hepatica and F. gigantica, by using rabbit hyper immune serum raised against these antigens. Adult worms were collected from bile ducts of infected animals and species of the fluke was confirmed by RFLP-PCR. ES and somatic antigens of both species were prepared. Rabbits were subcutaneously immunized with either ES or somatic antigens to produce antibodies against these antigens. SDS-PAGE pattern of F. hepatica and F. gigantica somatic antigens was similar and both of them revealed 30 protein bands, ranging from 18 to 180 kDa. In contrast, SDS-PAGE pattern of ES antigen of the two species was different. While protein bands with molecular weight of 18, 27, 29, 48, and 62 kDa were common in both species, bands of 19, 45, 55 and 58 kDa were only noticed in F. hepatica ES antigen. Rabbit polyclonal antibodies, raised against F. hepatica and F. gigantica ES antigen, reacted with main five protein bands, 25, 27, 29, 62 and 67 kDa and polyclonal antibodies raised against somatic antigens of both species reacted with three protein bands, 25, 27 and 72 kDa. Thus, the 25, 27 and 29 kDa protein bands may serve as immunodominant antigens, which might be considered for serodiagnosis of fasciolosis. Moreover, bands of 62 and 67 kDa in ES antigen and 72 kDa in somatic antigens of both species were immunodominant and might be suitable candidate for development of serological assays for diagnosis of fasciolosis.

  16. A Role For Mitochondria In Antigen Processing And Presentation.

    Science.gov (United States)

    Bonifaz, Lc; Cervantes-Silva, Mp; Ontiveros-Dotor, E; López-Villegas, Eo; Sánchez-García, Fj

    2014-09-23

    Immune synapse formation is critical for T lymphocyte activation, and mitochondria have a role in this process, by localizing close to the immune synapse, regulating intracellular calcium concentration, and providing locally required ATP. The interaction between antigen presenting cells (APCs) and T lymphocytes is a two-way signaling process. However, the role of mitochondria in antigen presenting cells during this process remains unknown. For APCs to be able to activate T lymphocytes, they must first engage in an antigen-uptake, -processing, and -presentation process. Here we show that HEL-loaded B lymphocytes, as a type of APCs, undergo a small but significant mitochondrial depolarization by 1-2 h following antigen exposure thus suggesting an increase in their metabolic demands. Inhibition of ATP synthase (oligomycin) or mitochondrial Ca(2+) uniporter (MCU) (Ruthenium red) had no effect on antigen uptake. Therefore, antigen processing and antigen presentation were further analyzed. Oligomycin treatment reduced the amount of specific MHC-peptide complexes but not total MHC II on the cell membrane of B lymphocytes which correlated with a decrease in antigen presentation. However, oligomycin also reduced antigen presentation by B lymphocytes that endogenously express HEL and by B lymphocytes loaded with the HEL48-62 peptide, although to a lesser extent. ATP synthase inhibition and MCU inhibition had a clear inhibitory effect on antigen processing (DQ-OVA). Taking together these results suggest that ATP synthase and MCU are relevant for antigen processing and presentation. Finally, APCs mitochondria were found to re-organize towards the APC-T immune synapse. This article is protected by copyright. All rights reserved.

  17. Sublingual immunization with M2-based vaccine induces broad protective immunity against influenza.

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    Byoung-Shik Shim

    Full Text Available BACKGROUND: The ectodomain of matrix protein 2 (M2e of influenza A virus is a rationale target antigen candidate for the development of a universal vaccine against influenza as M2e undergoes little sequence variation amongst human influenza A strains. Vaccine-induced M2e-specific antibodies (Abs have been shown to display significant cross-protective activity in animal models. M2e-based vaccine constructs have been shown to be more protective when administered by the intranasal (i.n. route than after parenteral injection. However, i.n. administration of vaccines poses rare but serious safety issues associated with retrograde passage of inhaled antigens and adjuvants through the olfactory epithelium. In this study, we examined whether the sublingual (s.l. route could serve as a safe and effective alternative mucosal delivery route for administering a prototype M2e-based vaccine. The mechanism whereby s.l. immunization with M2e vaccine candidate induces broad protection against infection with different influenza virus subtypes was explored. METHODS AND RESULTS: A recombinant M2 protein with three tandem copies of the M2e (3M2eC was expressed in Escherichia coli. Parenteral immunizations of mice with 3M2eC induced high levels of M2e-specific serum Abs but failed to provide complete protection against lethal challenge with influenza virus. In contrast, s.l. immunization with 3M2eC was superior for inducing protection in mice. In the latter animals, protection was associated with specific Ab responses in the lungs. CONCLUSIONS: The results demonstrate that s.l. immunization with 3M2eC vaccine induced airway mucosal immune responses along with broad cross-protective immunity to influenza. These findings may contribute to the understanding of the M2-based vaccine approach to control epidemic and pandemic influenza infections.

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

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    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

  19. Protectome analysis: a new selective bioinformatics tool for bacterial vaccine candidate discovery.

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    Altindis, Emrah; Cozzi, Roberta; Di Palo, Benedetta; Necchi, Francesca; Mishra, Ravi P; Fontana, Maria Rita; Soriani, Marco; Bagnoli, Fabio; Maione, Domenico; Grandi, Guido; Liberatori, Sabrina

    2015-02-01

    New generation vaccines are in demand to include only the key antigens sufficient to confer protective immunity among the plethora of pathogen molecules. In the last decade, large-scale genomics-based technologies have emerged. Among them, the Reverse Vaccinology approach was successfully applied to the development of an innovative vaccine against Neisseria meningitidis serogroup B, now available on the market with the commercial name BEXSERO® (Novartis Vaccines). The limiting step of such approaches is the number of antigens to be tested in in vivo models. Several laboratories have been trying to refine the original approach in order to get to the identification of the relevant antigens straight from the genome. Here we report a new bioinformatics tool that moves a first step in this direction. The tool has been developed by identifying structural/functional features recurring in known bacterial protective antigens, the so called "Protectome space," and using such "protective signatures" for protective antigen discovery. In particular, we applied this new approach to Staphylococcus aureus and Group B Streptococcus and we show that not only already known protective antigens were re-discovered, but also two new protective antigens were identified.

  20. PROTECTING THE PAST

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Promoting folk culture has become an important mission for some local governments, especially in ethnic minority areas Folk culture is drawing increasing attention as people's awareness of protecting their heritage has grown. But it is also evident that such protection efforts can bring economic benefits. Hubei, in central China, is one of the beneficiaries of folk culture protection. Seventeen of the 501 candidates for the

  1. Focal radiation therapy combined with 4-1BB activation and CTLA-4 blockade yields long-term survival and a protective antigen-specific memory response in a murine glioma model.

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    Zineb Belcaid

    Full Text Available BACKGROUND: Glioblastoma (GBM is the most common malignant brain tumor in adults and is associated with a poor prognosis. Cytotoxic T lymphocyte antigen -4 (CTLA-4 blocking antibodies have demonstrated an ability to generate robust antitumor immune responses against a variety of solid tumors. 4-1BB (CD137 is expressed by activated T lymphocytes and served as a co-stimulatory signal, which promotes cytotoxic function. Here, we evaluate a combination immunotherapy regimen involving 4-1BB activation, CTLA-4 blockade, and focal radiation therapy in an immune-competent intracranial GBM model. METHODS: GL261-luciferace cells were stereotactically implanted in the striatum of C57BL/6 mice. Mice were treated with a triple therapy regimen consisted of 4-1BB agonist antibodies, CTLA-4 blocking antibodies, and focal radiation therapy using a small animal radiation research platform and mice were followed for survival. Numbers of brain-infiltrating lymphocytes were analyzed by FACS analysis. CD4 or CD8 depleting antibodies were administered to determine the relative contribution of T helper and cytotoxic T cells in this regimen. To evaluate the ability of this immunotherapy to generate an antigen-specific memory response, long-term survivors were re-challenged with GL261 glioma en B16 melanoma flank tumors. RESULTS: Mice treated with triple therapy had increased survival compared to mice treated with focal radiation therapy and immunotherapy with 4-1BB activation and CTLA-4 blockade. Animals treated with triple therapy exhibited at least 50% long-term tumor free survival. Treatment with triple therapy resulted in a higher density of CD4+ and CD8+ tumor infiltrating lymphocytes. Mechanistically, depletion of CD4+ T cells abrogated the antitumor efficacy of triple therapy, while depletion of CD8+ T cells had no effect on the treatment response. CONCLUSION: Combination therapy with 4-1BB activation and CTLA-4 blockade in the setting of focal radiation therapy

  2. Expression, purification and antigenicity of Neospora caninum-antigens using silkworm larvae targeting for subunit vaccines.

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    Otsuki, Takahiro; Dong, Jinhua; Kato, Tatsuya; Park, Enoch Y

    2013-02-18

    Infection of Neospora caninum causes abortion in cattle, which has a serious worldwide impact on the economic performance of the dairy and beef industries. Now, inexpensive and efficacious vaccines are required to protect cattle from neosporosis in livestock industry. In this study, N. caninum surface antigen 1 (SAG1) and SAG1-related sequence 2 (SRS2) were expressed in hemolymph of silkworm larvae as a soluble form. Expressed SAG1 and SRS2 clearly showed antigenicity against N. caninum-positive sera of cow. SAG1 and SRS2 were purified to near homogeneity from hemolymph of silkworm larvae using anti-FLAG M2 antibody agarose: approximately 1.7 mg of SAG1 from 10 silkworm larvae and 370 μg of SRS2 from 17 silkworm larvae. Mice that were injected by antigens induced antibodies against SAG1 and SRS2. This study indicates that it is possible that this silkworm expression system leads to a large-scale production of N. caninum-antigens with biological function and low production cost. Bombyx mori nucleopolyhedrovirus (BmNPV) bacmid expression system paves the way to produce largely and rapidly these recombinant antigens for its application to subunit vaccines against neosporosis in cattle.

  3. A Francisella tularensis live vaccine strain that improves stimulation of antigen-presenting cells does not enhance vaccine efficacy.

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    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.

  4. Human T cell recognition of the blood stage antigen Plasmodium hypoxanthine guanine xanthine phosphoribosyl transferase (HGXPRT in acute malaria

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    Woodberry Tonia

    2009-06-01

    Full Text Available Abstract Background The Plasmodium purine salvage enzyme, hypoxanthine guanine xanthine phosphoribosyl transferase (HGXPRT can protect mice against Plasmodium yoelii pRBC challenge in a T cell-dependent manner and has, therefore, been proposed as a novel vaccine candidate. It is not known whether natural exposure to Plasmodium falciparum stimulates HGXPRT T cell reactivity in humans. Methods PBMC and plasma collected from malaria-exposed Indonesians during infection and 7–28 days after anti-malarial therapy, were assessed for HGXPRT recognition using CFSE proliferation, IFNγ ELISPOT assay and ELISA. Results HGXPRT-specific T cell proliferation was found in 44% of patients during acute infection; in 80% of responders both CD4+ and CD8+ T cell subsets proliferated. Antigen-specific T cell proliferation was largely lost within 28 days of parasite clearance. HGXPRT-specific IFN-γ production was more frequent 28 days after treatment than during acute infection. HGXPRT-specific plasma IgG was undetectable even in individuals exposed to malaria for at least two years. Conclusion The prevalence of acute proliferative and convalescent IFNγ responses to HGXPRT demonstrates cellular immunogenicity in humans. Further studies to determine minimal HGXPRT epitopes, the specificity of responses for Plasmodia and associations with protection are required. Frequent and robust T cell proliferation, high sequence conservation among Plasmodium species and absent IgG responses distinguish HGXPRT from other malaria antigens.

  5. Rapid discovery of peptide capture candidates with demonstrated specificity for structurally similar toxins

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    Sarkes, Deborah A.; Hurley, Margaret M.; Coppock, Matthew B.; Farrell, Mikella E.; Pellegrino, Paul M.; Stratis-Cullum, Dimitra N.

    2016-05-01

    Peptides have emerged as viable alternatives to antibodies for molecular-based sensing due to their similarity in recognition ability despite their relative structural simplicity. Various methods for peptide capture reagent discovery exist, including phage display, yeast display, and bacterial display. One of the primary advantages of peptide discovery by bacterial display technology is the speed to candidate peptide capture agent, due to both rapid growth of bacteria and direct utilization of the sorted cells displaying each individual peptide for the subsequent round of biopanning. We have previously isolated peptide affinity reagents towards protective antigen of Bacillus anthracis using a commercially available automated magnetic sorting platform with improved enrichment as compared to manual magnetic sorting. In this work, we focus on adapting our automated biopanning method to a more challenging sort, to demonstrate the specificity possible with peptide capture agents. This was achieved using non-toxic, recombinant variants of ricin and abrin, RiVax and abrax, respectively, which are structurally similar Type II ribosomal inactivating proteins with significant sequence homology. After only two rounds of biopanning, enrichment of peptide capture candidates binding abrax but not RiVax was achieved as demonstrated by Fluorescence Activated Cell Sorting (FACS) studies. Further sorting optimization included negative sorting against RiVax, proper selection of autoMACS programs for specific sorting rounds, and using freshly made buffer and freshly thawed protein target for each round of biopanning for continued enrichment over all four rounds. Most of the resulting candidates from biopanning for abrax binding peptides were able to bind abrax but not RiVax, demonstrating that short peptide sequences can be highly specific even at this early discovery stage.

  6. Functional Exposed Amino Acids of OSPA as a Candidate for Lyme disease Vaccine

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    Negin Kafee

    2016-06-01

    Full Text Available Lyme disease is caused by the bacterium Borreliaburgdorferi and is transmitted to humans through the bite of infected black legged ticks. Typical symptoms include fever, headache, fatigue, and a characteristic skin rash called erythema migrans. If left untreated, infection can spread to joints, the heart, and the nervous system. Lyme disease is diagnosed based on symptoms, physical findings (e.g., rash, and the possibility of exposure to infected ticks. The protective role of antibodies to B. burgdorferi has been explored in animal models of Lyme disease. Findings indicated that antibodies against OspA were protective, making this antigen a likely candidate for a vaccine. Early clinical trials demonstrated that recombinant OspA was immunogenic and well tolerated, even in subjects with a history of Lyme disease. The present study was designed to in silico resolving the major obstacles in the control or in prevention of lyme diseases. We exploited bioinformatic tools to better understanding and characterizing the OspAstructure and select appropriate regions as effectiveB cell epitops.

  7. Evaluation of enteric-coated tablets as a whole cell inactivated vaccine candidate against Vibrio cholerae.

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    Fernández, Sonsire; Año, Gemma; Castaño, Jorge; Pino, Yadira; Uribarri, Evangelina; Riverón, Luis A; Cedré, Bárbara; Valmaseda, Tania; Falero, Gustavo; Pérez, José L; Infante, Juan F; García, Luis G; Solís, Rosa L; Sierra, Gustavo; Talavera, Arturo

    2013-01-01

    A vaccine candidate against cholera was developed in the form of oral tablets to avoid difficulties during application exhibited by current whole cell inactivated cholera vaccines. In this study, enteric-coated tablets were used to improve the protection of the active compound from gastric acidity. Tablets containing heat-killed whole cells of Vibrio cholerae strain C7258 as the active pharmaceutical compound was enteric-coated with the polymer Kollicoat(®) MAE-100P, which protected them efficiently from acidity when a disintegration test was carried out. Enzyme-linked immunosorbent assay (ELISA) anti-lipopolysaccharide (LPS) inhibition test and Western blot assay revealed the presence of V. cholerae antigens as LPS, mannose-sensitive haemagglutinin (MSHA) and outer membrane protein U (Omp U) in enteric-coated tablets. Immunogenicity studies (ELISA and vibriocidal test) carried out by intraduodenal administration in rabbits showed that the coating process of tablets did not affect the immunogenicity of V. cholerae-inactivated cells. In addition, no differences were observed in the immune response elicited by enteric-coated or uncoated tablets, particularly because the animal model and immunization route used did not allow discriminating between acid resistances of both tablets formulations in vivo. Clinical studies with volunteers will be required to elucidate this aspect, but the results suggest the possibility of using enteric-coated tablets as a final pharmaceutical product for a cholera vaccine.

  8. Antigenic and genetic diversity of human enterovirus 71 from 2009 to 2012, Taiwan.

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    Yuan-Pin Huang

    Full Text Available Different subgenogroups of enterovirus 71 (EV-71 have caused numerous outbreaks of hand, foot, and mouth disease worldwide, especially in the Asia-Pacific region. During the development of a vaccine against EV-71, the genetic and antigenic diversities of EV-71 isolates from Taiwan were analyzed by phylogenetic analyses and neutralization tests. The results showed that the dominant genogroups had changed twice, from B to C and from C to B, between 2009 and 2012. The subgenogroup B5 (B5b cluster was dominant in 2008-2009 but was replaced by subgenogroup C4 in 2010-2011. From the end of 2011 to 2012, the re-emerging subgenogroup B5 (B5c cluster was identified as the dominant subgenogroup of EV-71 outbreaks, and subgenogroups C2 and C4 were detected in sporadic cases. Interestingly, the amino acid substitution at position 145 in the VP1 gene was observed in some strains isolated from patients with acute flaccid paralysis. Furthermore, thirty-five strains and their corresponding serum samples were used to analyze the cross-protections and antigenic diversities among different subgenogroups (C4a, C5, B4, B5b, B5c, and C2-like of EV-71. Evident antigenic diversity existed only for the C2-like subgenogroup, which was not effectively neutralized by other serum samples. In contrast, the anti-C2-like serum sample showed broad cross-reactivity against all other subgenogroups. Therefore, these results may provide valuable information for the selection of EV-71 vaccine candidates and the evolution of EV-71 subgenogroups in Taiwan from 2009 to 2012.

  9. Vaccine candidates for leishmaniasis: a review.

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    Nagill, Rajeev; Kaur, Sukhbir

    2011-10-01

    Leishmaniasis is a diverse group of clinical syndromes caused by protozoan parasites of the genus Leishmania. The clinical manifestation of the disease varies from self-limiting cutaneous lesions to progressive visceral disease. It is estimated that 350 million people are at risk in 88 countries, with a global incidence of 1-1.5 million cases of cutaneous and 500,000 cases of visceral leishmaniasis. The key control measures mainly rely on early case detection and chemotherapy which has been hampered by the toxicity of drugs, side-effects and by the emergence of drug resistance in parasites. Control of reservoir host and vector is difficult due to operational difficulties and frequent relapses in the host. Therefore, the development of effective and affordable vaccine against leishmaniasis is highly desirable. Although considerable progress has been made over the last decade in understanding immune mechanisms underlying potential candidate antigens, including killed, live attenuated parasites, crude parasites, pure or recombinant Leishmania proteins or DNA encoding leishmanial proteins, as well as immunomodulators from sand fly saliva, very few candidate vaccines have progressed beyond the experimental stage. As such there is no vaccine against any form of human leishmaniasis. In recent years, however, much interest has been stimulated towards vaccination against leishmaniasis focused mainly on cutaneous leishmaniasis with fewer attempts against visceral leishmaniasis.

  10. Transgenic parasites stably expressing full-length Plasmodium falciparum circumsporozoite protein as a model for vaccine down-selection in mice using sterile protection as an endpoint.

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    Porter, Michael D; Nicki, Jennifer; Pool, Christopher D; DeBot, Margot; Illam, Ratish M; Brando, Clara; Bozick, Brooke; De La Vega, Patricia; Angra, Divya; Spaccapelo, Roberta; Crisanti, Andrea; Murphy, Jittawadee R; Bennett, Jason W; Schwenk, Robert J; Ockenhouse, Christian F; Dutta, Sheetij

    2013-06-01

    Circumsporozoite protein (CSP) of Plasmodium falciparum is a protective human malaria vaccine candidate. There is an urgent need for models that can rapidly down-select novel CSP-based vaccine candidates. In the present study, the mouse-mosquito transmission cycle of a transgenic Plasmodium berghei malaria parasite stably expressing a functional full-length P. falciparum CSP was optimized to consistently produce infective sporozoites for protection studies. A minimal sporozoite challenge dose was established, and protection was defined as the absence of blood-stage parasites 14 days after intravenous challenge. The specificity of protection was confirmed by vaccinating mice with multiple CSP constructs of differing lengths and compositions. Constructs that induced high NANP repeat-specific antibody titers in enzyme-linked immunosorbent assays were protective, and the degree of protection was dependent on the antigen dose. There was a positive correlation between antibody avidity and protection. The antibodies in the protected mice recognized the native CSP on the parasites and showed sporozoite invasion inhibitory activity. Passive transfer of anti-CSP antibodies into naive mice also induced protection. Thus, we have demonstrated the utility of a mouse efficacy model to down-select human CSP-based vaccine formulations.

  11. Biochemical and Structural Analysis of Bacterial O-antigen Chain Length Regulator Proteins Reveals a Conserved Quaternary Structure*

    OpenAIRE

    Larue, Kane; Kimber, Matthew S.; Ford, Robert; Whitfield, Chris

    2009-01-01

    Lipopolysaccharide (LPS) is a major component of the Gram-negative outer membrane and is an important virulence determinant. The O-antigen polysaccharide of the LPS molecule provides protection from host defenses, and the length of O-antigen chains plays a pivotal role. In the Wzy-dependent O-antigen biosynthesis pathway, the integral inner membrane protein Wzz determines the O-antigen chain length. How these proteins function is currently unknown, but the hypothesis i...

  12. Identification and validation of a linear protective neutralizing epitope in the β-pore domain of alpha toxin.

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    Jon Oscherwitz

    Full Text Available The plethora of virulence factors associated with Staphylococcus aureus make this bacterium an attractive candidate for a molecularly-designed epitope-focused vaccine. This approach, which necessitates the identification of neutralizing epitopes for incorporation into a vaccine construct, is being evaluated for pathogens where conventional approaches have failed to elicit protective humoral responses, like HIV-1 and malaria, but may also hold promise for pathogens like S. aureus, where the elicitation of humoral immunity against multiple virulence factors may be required for development of an effective vaccine. Among the virulence factors employed by S. aureus, animal model and epidemiological data suggest that alpha toxin, a multimeric β-pore forming toxin like protective antigen from Bacillus anthracis, is partic