Virus-like particles displaying H5, H7, H9 hemagglutinins and N1 neuraminidase elicit protective immunity to heterologous avian influenza viruses in chickens

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Pushko, Peter, E-mail: ppushko@medigen-usa.com [Medigen, Inc., 8420 Gas House Pike, Suite S, Frederick, MD 21701 (United States); Tretyakova, Irina; Hidajat, Rachmat [Medigen, Inc., 8420 Gas House Pike, Suite S, Frederick, MD 21701 (United States); Zsak, Aniko; Chrzastek, Klaudia [USDA SEPRL, 934 College Station Rd, Athens, GA (United States); Tumpey, Terrence M. [Influenza Division, CDC,1600 Clifton Road N.E., Atlanta, GA (United States); Kapczynski, Darrell R. [USDA SEPRL, 934 College Station Rd, Athens, GA (United States)

2017-01-15

Avian influenza (AI) viruses circulating in wild birds pose a serious threat to public health. Human and veterinary vaccines against AI subtypes are needed. Here we prepared triple-subtype VLPs that co-localized H5, H7 and H9 antigens derived from H5N1, H7N3 and H9N2 viruses. VLPs also contained influenza N1 neuraminidase and retroviral gag protein. The H5/H7/H9/N1/gag VLPs were prepared using baculovirus expression. Biochemical, functional and antigenic characteristics were determined including hemagglutination and neuraminidase enzyme activities. VLPs were further evaluated in a chicken AI challenge model for safety, immunogenicity and protective efficacy against heterologous AI viruses including H5N2, H7N3 and H9N2 subtypes. All vaccinated birds survived challenges with H5N2 and H7N3 highly pathogenic AI (HPAI) viruses, while all controls died. Immune response was also detectable after challenge with low pathogenicity AI (LPAI) H9N2 virus suggesting that H5/H7/H9/N1/gag VLPs represent a promising approach for the development of broadly protective AI vaccine. - Highlights: •VLPs were prepared that co-localized H5, H7 and H9 subtypes in a VLP envelope. •VLPs were characterized including electron microscopy, HA assay and NA enzyme activity. •Experimental VLP vaccine was evaluated in an avian influenza challenge model. •VLPs induced immune responses against heterologous H5, H7 and H9 virus challenges.

Trivalent combination vaccine induces broad heterologous immune responses to norovirus and rotavirus in mice.

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Kirsi Tamminen

Full Text Available Rotavirus (RV and norovirus (NoV are the two major causes of viral gastroenteritis (GE in children worldwide. We have developed an injectable vaccine design to prevent infection or GE induced with these enteric viruses. The trivalent combination vaccine consists of NoV capsid (VP1 derived virus-like particles (VLPs of GI-3 and GII-4 representing the two major NoV genogroups and tubular RV recombinant VP6 (rVP6, the most conserved and abundant RV protein. Each component was produced in insect cells by a recombinant baculovirus expression system and combined in vitro. The vaccine components were administered intramuscularly to BALB/c mice either separately or in the trivalent combination. High levels of NoV and RV type specific serum IgGs with high avidity (>50% as well as intestinal IgGs were detected in the immunized mice. Cross-reactive IgG antibodies were also elicited against heterologous NoV VLPs not used for immunization (GII-4 NO, GII-12 and GI-1 VLPs and to different RVs from cell cultures. NoV-specific serum antibodies blocked binding of homologous and heterologous VLPs to the putative receptors, histo-blood group antigens, suggesting broad NoV neutralizing activity of the sera. Mucosal antibodies of mice immunized with the trivalent combination vaccine inhibited RV infection in vitro. In addition, cross-reactive T cell immune responses to NoV and RV-specific antigens were detected. All the responses were sustained for up to six months. No mutual inhibition of the components in the trivalent vaccine combination was observed. In conclusion, the NoV GI and GII VLPs combination induced broader cross-reactive and potentially neutralizing immune responses than either of the VLPs alone. Therefore, trivalent vaccine might induce protective immune responses to the vast majority of circulating NoV and RV genotypes.

Insect immunity shows specificity in protection upon secondary pathogen exposure.

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Sadd, Ben M; Schmid-Hempel, Paul

2006-06-20

Immunological memory in vertebrates, conferring lasting specific protection after an initial pathogen exposure, has implications for a broad spectrum of evolutionary, epidemiological, and medical phenomena . However, the existence of specificity in protection upon secondary pathogen exposure in invertebrates remains controversial . To separate this functional phenomenon from a particular mechanism, we refer to it as specific immune priming. We investigate the presence of specific immune priming in workers of the social insect Bombus terrestris. Using three bacterial pathogens, we test whether a prior homologous pathogen exposure gives a benefit in terms of long-term protection against a later challenge, over and above a heterologous combination. With a reciprocally designed initial and second-exposure protocol (i.e., all combinations of bacteria were tested), we demonstrate, even several weeks after the clearance of a first exposure, increased protection and narrow specificity upon secondary exposure. This demonstrates that the invertebrate immune system is functionally capable of unexpectedly specific and durable induced protection. Ultimately, despite general broad differences between vertebrates and invertebrates, the ability of both immune systems to show specificity in protection suggests that their immune defenses have found comparable solutions to similar selective pressures over evolutionary time.

Long-Lasting Effects of BCG Vaccination on Both Heterologous Th1/Th17 Responses and Innate Trained Immunity

DEFF Research Database (Denmark)

Kleinnijenhuis, Johanneke; Quintin, Jessica; Preijers, Frank

2013-01-01

'. In the present study we assessed whether BCG was able to induce long-lasting effects on both trained immunity and heterologous T helper 1 (Th1) and Th17 immune responses 1 year after vaccination. The production of TNFα and IL-1β to mycobacteria or unrelated pathogens was higher after 2 weeks and 3 months...... in proinflammatory cytokine production after stimulation with the TLR4 ligand lipopolysaccharide. The heterologous production of Th1 (IFN-γ) and Th17 (IL-17 and IL-22) immune responses to nonmycobacterial stimulation remained strongly elevated even 1 year after BCG vaccination. In conclusion, BCG induces sustained...... changes in the immune system associated with a nonspecific response to infections both at the level of innate trained immunity and at the level of heterologous Th1/Th17 responses. © 2013 S. Karger AG, Basel....

Suppression of adaptive immunity to heterologous antigens during Plasmodium infection through hemozoin-induced failure of dendritic cell function

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Phillips R

2006-04-01

Full Text Available Abstract Background Dendritic cells (DCs are central to the initiation and regulation of the adaptive immune response during infection. Modulation of DC function may therefore allow evasion of the immune system by pathogens. Significant depression of the host's systemic immune response to both concurrent infections and heterologous vaccines has been observed during malaria infection, but the mechanisms underlying this immune hyporesponsiveness are controversial. Results Here, we demonstrate that the blood stages of malaria infection induce a failure of DC function in vitro and in vivo, causing suboptimal activation of T cells involved in heterologous immune responses. This effect on T-cell activation can be transferred to uninfected recipients by DCs isolated from infected mice. Significantly, T cells activated by these DCs subsequently lack effector function, as demonstrated by a failure to migrate to lymphoid-organ follicles, resulting in an absence of B-cell responses to heterologous antigens. Fractionation studies show that hemozoin, rather than infected erythrocyte (red blood cell membranes, reproduces the effect of intact infected red blood cells on DCs. Furthermore, hemozoin-containing DCs could be identified in T-cell areas of the spleen in vivo. Conclusion Plasmodium infection inhibits the induction of adaptive immunity to heterologous antigens by modulating DC function, providing a potential explanation for epidemiological studies linking endemic malaria with secondary infections and reduced vaccine efficacy.

Evaluation of immune response and protective effect of four vaccines against the tick-borne encephalitis virus.

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Morozova, O V; Bakhvalova, V N; Potapova, O F; Grishechkin, A E; Isaeva, E I; Aldarov, K V; Klinov, D V; Vorovich, M F

2014-05-23

Among three main subtypes of the tick-borne encephalitis virus (TBEV), the Siberian subtype is currently dominant in a majority of the endemic regions of Russia. However, inactivated vaccines are based on TBEV strains of the heterologous Far Eastern or the European subtypes isolated 40-77 years ago. To analyze the efficacy of the available vaccines against currently prevailing TBEV isolates of the Siberian subtype, mice were immunized subcutaneously three times (one group per each vaccine). The expression of seven cytokine genes was determined using RT-PCR. Sera were studied using homologous and heterologous ELISA, hemagglutination inhibition (HI) and neutralization tests with TBEV strains of the Far Eastern, Siberian and European subtypes. Cross-protective efficacy of the vaccines was evaluated with the TBEV strain 2689 of Siberian subtype isolated from an ixodid tick from the Novosibirsk, South-Western Siberia, Russia in 2010. The cytokine gene expression profile indicates a predominantly Th2 response due to exogenous antigen presentation. Titers for homologous combinations of vaccine strain and strain in ELISA, HI and neutralization tests exceeded those for heterologous antigen-antibody pairs. Despite antibody detection by means of ELISA, HI and neutralization tests, the mouse protection afforded by the vaccines differed significantly. Complete protection of mice challenged with 100 LD50 virus of the Siberian subtype was induced by the vaccine "Encevir" ("Microgen", Tomsk, Russia). The minimal immunization doze (MID50) of "Encevir" protecting 50% of the mice was less than 0.0016 ml. Partial protective effect of vaccines produced in Moscow, Russia and Austria revealed MID50 within recommended intervals (0.001-0.017 ml). However, the MID50 for the vaccine "Encepur" (Novartis, Germany) 0.04 ml exceeded acceptable limits with total loss of mice immunized with vaccine diluted 32, 100 and 320 fold. These results suggest regular evaluation of TBEV vaccines in regions

Heterologous humoral immune response in patients treated with human growth hormone from different sources

International Nuclear Information System (INIS)

Cardoso, A.I.; Llera, A.S.; Iacono, R.F.

1993-01-01

The existence of homologous anti-human growth hormone (anti-hGH) and heterologous anti-bovine growth hormone (anti-bGH) humoral immune responses in hypopituitary patients under hGH therapy has been reported previously. In order to study the influence of the hormone source, both responses were compared by radiobinding assays performed with [ 125 I]hGH or [ 125 I]bGH as tracers. 57 hypopituitary patients treated with extractive hGH, recombinant methionyl hGH or authentic recombinant hGH were studied. A very low incidence of heterologous antibodies was found in patients under recombinant hGH therapy, contrary to the high incidence observed in patients treated with extractive hGH preparations. In addition, immunochemical studies performed with a synthetic peptide (hGH 44-128) indicated that this peptide exhibited, in the anti-bGH/[ 125 I]bGH radioimmunoassay system, higher reactivity than the native hGH, suggesting that such fragment resembled an altered conformation of the hormone. The high heterologous response elicited only by the extractive hGH along with the behaviour of the hGH 44-128 fragment supports the fact that the extraction and purification procedures in extractive preparations may alter slightly the structure of the hGH molecule and trigger a heterologous immune response. 16 refs., 4 figs., 1 tab

Heterologous humoral immune response in patients treated with human growth hormone from different sources

Energy Technology Data Exchange (ETDEWEB)

Cardoso, A.I.; Llera, A.S.; Iacono, R.F. (and others) (Inst. de Estudios de la Inmunidad Humoral, Buenos Aires (Argentina))

1993-07-01

The existence of homologous anti-human growth hormone (anti-hGH) and heterologous anti-bovine growth hormone (anti-bGH) humoral immune responses in hypopituitary patients under hGH therapy has been reported previously. In order to study the influence of the hormone source, both responses were compared by radiobinding assays performed with [[sup 125]I]hGH or [[sup 125]I]bGH as tracers. 57 hypopituitary patients treated with extractive hGH, recombinant methionyl hGH or authentic recombinant hGH were studied. A very low incidence of heterologous antibodies was found in patients under recombinant hGH therapy, contrary to the high incidence observed in patients treated with extractive hGH preparations. In addition, immunochemical studies performed with a synthetic peptide (hGH 44-128) indicated that this peptide exhibited, in the anti-bGH/[[sup 125]I]bGH radioimmunoassay system, higher reactivity than the native hGH, suggesting that such fragment resembled an altered conformation of the hormone. The high heterologous response elicited only by the extractive hGH along with the behaviour of the hGH 44-128 fragment supports the fact that the extraction and purification procedures in extractive preparations may alter slightly the structure of the hGH molecule and trigger a heterologous immune response. 16 refs., 4 figs., 1 tab.

Inactivated Recombinant Rabies Viruses Displaying Canine Distemper Virus Glycoproteins Induce Protective Immunity against Both Pathogens.

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da Fontoura Budaszewski, Renata; Hudacek, Andrew; Sawatsky, Bevan; Krämer, Beate; Yin, Xiangping; Schnell, Matthias J; von Messling, Veronika

2017-04-15

The development of multivalent vaccines is an attractive methodology for the simultaneous prevention of several infectious diseases in vulnerable populations. Both canine distemper virus (CDV) and rabies virus (RABV) cause lethal disease in wild and domestic carnivores. While RABV vaccines are inactivated, the live-attenuated CDV vaccines retain residual virulence for highly susceptible wildlife species. In this study, we developed recombinant bivalent vaccine candidates based on recombinant vaccine strain rabies virus particles, which concurrently display the protective CDV and RABV glycoprotein antigens. The recombinant viruses replicated to near-wild-type titers, and the heterologous glycoproteins were efficiently expressed and incorporated in the viral particles. Immunization of ferrets with beta-propiolactone-inactivated recombinant virus particles elicited protective RABV antibody titers, and animals immunized with a combination of CDV attachment protein- and fusion protein-expressing recombinant viruses were protected from lethal CDV challenge. However, animals that were immunized with only a RABV expressing the attachment protein of CDV vaccine strain Onderstepoort succumbed to infection with a more recent wild-type strain, indicating that immune responses to the more conserved fusion protein contribute to protection against heterologous CDV strains. IMPORTANCE Rabies virus and canine distemper virus (CDV) cause high mortality rates and death in many carnivores. While rabies vaccines are inactivated and thus have an excellent safety profile and high stability, live-attenuated CDV vaccines can retain residual virulence in highly susceptible species. Here we generated recombinant inactivated rabies viruses that carry one of the CDV glycoproteins on their surface. Ferrets immunized twice with a mix of recombinant rabies viruses carrying the CDV fusion and attachment glycoproteins were protected from lethal CDV challenge, whereas all animals that received

Partial protection of SIV-infected rhesus monkeys against superinfection with a heterologous SIV isolate

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Korber, Bette [Los Alamos National Laboratory

2009-01-01

Although there is increasing evidence that individuals already infected with human immunodeficiency virus type 1 (HIV-1) can be infected with a heterologous strain of the virus, the extent of protection against superinfection conferred by the first infection and the biologic consequences of superinfection are not well understood. We explored these questions in the simian immunodeficiency virus (SIV)/rhesus monkey model of HIV-1/AIDS. We infected cohorts of rhesus monkeys with either SIVmac251 or SIVsmE660 and then exposed animals to the reciprocal virus through intrarectal inoculations. Employing a quantitative real-time PCR assay, we determined the replication kinetics of the two strains of virus for 20 weeks. We found that primary infection with a replication-competent virus did not protect against acquisition of infection by a heterologous virus but did confer relative control of the superinfecting virus. In animals that became superinfected, there was a reduction in peak replication and rapid control of the second virus. The relative susceptibility to superinfection was not correlated with CD4(+) T-cell count, CD4(+) memory T-cell subsets, cytokine production by virus-specific CD8(+) or CD4(+) cells, or neutralizing antibodies at the time of exposure to the second virus. Although there were transient increases in viral loads of the primary virus and a modest decline in CD4(+) T-cell counts after superinfection, there was no evidence of disease acceleration. These findings indicate that an immunodeficiency virus infection confers partial protection against a second immunodeficiency virus infection, but this protection may be mediated by mechanisms other than classical adaptive immune responses.

Growth, immune responses and protection of Nile tilapia Oreochromis niloticus immunized with formalin-killed Streptococcus agalactiae serotype Ia and III vaccines

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Atchariya Suwannasang

2017-08-01

Full Text Available The protective efficacy of formalin-killed Streptococcus agalactiae (Group B Streptococcus, GBS serotype Ia (GBS-Ia and III (GBS-III vaccines were assessed in Nile tilapia (Oreochromis niloticus. The fish with an average weight of 34.45± 0.08 g were immunized by intraperitoneal (i.p. injection with 4 different formalin-killed vaccines prepared from GBS-Ia (1x1010 CFU/mL, GBS-III (1x1010 CFU/mL, and combined GBS-Ia and GBS-III in an equal volume at final concentrations 1x1010 CFU/mL and 2x1010 CFU/mL in comparison with the non-immunized control group. At 2 and 4 weeks post vaccination, no significant differences were observed (p>0.05 among treatments in growth performance or haemato-immunological parameters, except the increased red blood cell at 2 weeks. Significantly increased antibody titers (p<0.05 against GBS-Ia and GBS-III antigens were noted in the groups immunized with homologous GBS vaccines, whereas the group reacted with heterologous GBS antigen showed less antibody titer as compared with the control group. The vaccination experiment indicated that i.p. injection of Nile tilapia with formalin-killed cells prepared from GBS-Ia or GBS-III provides significant protection, with relative percent survival (RPS value of 52.17 to 71.42%, against a challenge with the homologous serotype isolate, whereas the RPS in fish challenged with a heterologous serotype isolate varied from 20.00 to 53.57%. These results suggested that vaccines from either GBS-Ia or GBS-III have insufficient cross-protective efficacy against the other serotypes. However, a mixed vaccine produced from both GBS serotypes Ia and III provided significant protection with 65.00 to 95.66% RPS which could be an excellent vaccine to protect fish against streptococcosis caused by both GBS serotypes Ia and III.

Protection of macaques with diverse MHC genotypes against a heterologous SIV by vaccination with a deglycosylated live-attenuated SIV.

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Chie Sugimoto

Full Text Available HIV vaccine development has been hampered by issues such as undefined correlates of protection and extensive diversity of HIV. We addressed these issues using a previously established SIV-macaque model in which SIV mutants with deletions of multiple gp120 N-glycans function as potent live attenuated vaccines to induce near-sterile immunity against the parental pathogenic SIVmac239. In this study, we investigated the protective efficacy of these mutants against a highly pathogenic heterologous SIVsmE543-3 delivered intravenously to rhesus macaques with diverse MHC genotypes. All 11 vaccinated macaques contained the acute-phase infection with blood viral loads below the level of detection between 4 and 10 weeks postchallenge (pc, following a transient but marginal peak of viral replication at 2 weeks in only half of the challenged animals. In the chronic phase, seven vaccinees contained viral replication for over 80 weeks pc, while four did not. Neutralizing antibodies against challenge virus were not detected. Although overall levels of SIV specific T cell responses did not correlate with containment of acute and chronic viral replication, a critical role of cellular responses in the containment of viral replication was suggested. Emergence of viruses with altered fitness due to recombination between the vaccine and challenge viruses and increased gp120 glycosylation was linked to the failure to control SIV. These results demonstrate the induction of effective protective immune responses in a significant number of animals against heterologous virus by infection with deglycosylated attenuated SIV mutants in macaques with highly diverse MHC background. These findings suggest that broad HIV cross clade protection is possible, even in hosts with diverse genetic backgrounds. In summary, results of this study indicate that deglycosylated live-attenuated vaccines may provide a platform for the elucidation of correlates of protection needed for a

A combination vaccine comprising of inactivated enterovirus 71 and coxsackievirus A16 elicits balanced protective immunity against both viruses.

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Cai, Yicun; Ku, Zhiqiang; Liu, Qingwei; Leng, Qibin; Huang, Zhong

2014-05-01

Enterovirus 71 (EV71) and coxsackievirus A16 (CA16) are the two major causative agents of hand, foot and mouth disease (HFMD), which is an infectious disease frequently occurring in children. A bivalent vaccine against both EV71 and CA16 is highly desirable. In the present study, we compare monovalent inactivated EV71, monovalent inactivated CA16, and a combination vaccine candidate comprising of both inactivated EV71 and CA16, for their immunogenicity and in vivo protective efficacy. The two monovalent vaccines were found to elicit serum antibodies that potently neutralized the homologous virus but had no or weak neutralization activity against the heterologous one; in contrast, the bivalent vaccine immunized sera efficiently neutralized both EV71 and CA16. More importantly, passive immunization with the bivalent vaccine protected mice against either EV71 or CA16 lethal infections, whereas the monovalent vaccines only prevented the homologous but not the heterologous challenges. Together, our results demonstrate that the experimental bivalent vaccine comprising of inactivated EV71 and CA16 induces a balanced protective immunity against both EV71 and CA16, and thus provide proof-of-concept for further development of multivalent vaccines for broad protection against HFMD. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mucosal Immunity and Protective Efficacy of Intranasal Inactivated Influenza Vaccine Is Improved by Chitosan Nanoparticle Delivery in Pigs.

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Dhakal, Santosh; Renu, Sankar; Ghimire, Shristi; Shaan Lakshmanappa, Yashavanth; Hogshead, Bradley T; Feliciano-Ruiz, Ninoshkaly; Lu, Fangjia; HogenEsch, Harm; Krakowka, Steven; Lee, Chang Won; Renukaradhya, Gourapura J

2018-01-01

Annually, swine influenza A virus (SwIAV) causes severe economic loss to swine industry. Currently used inactivated SwIAV vaccines administered by intramuscular injection provide homologous protection, but limited heterologous protection against constantly evolving field viruses, attributable to the induction of inadequate levels of mucosal IgA and cellular immune responses in the respiratory tract. A novel vaccine delivery platform using mucoadhesive chitosan nanoparticles (CNPs) administered through intranasal (IN) route has the potential to elicit strong mucosal and systemic immune responses in pigs. In this study, we evaluated the immune responses and cross-protective efficacy of IN chitosan encapsulated inactivated SwIAV vaccine in pigs. Killed SwIAV H1N2 (δ-lineage) antigens (KAg) were encapsulated in chitosan polymer-based nanoparticles (CNPs-KAg). The candidate vaccine was administered twice IN as mist to nursery pigs. Vaccinates and controls were then challenged with a zoonotic and virulent heterologous SwIAV H1N1 (γ-lineage). Pigs vaccinated with CNPs-KAg exhibited an enhanced IgG serum antibody and mucosal secretory IgA antibody responses in nasal swabs, bronchoalveolar lavage (BAL) fluids, and lung lysates that were reactive against homologous (H1N2), heterologous (H1N1), and heterosubtypic (H3N2) influenza A virus strains. Prior to challenge, an increased frequency of cytotoxic T lymphocytes, antigen-specific lymphocyte proliferation, and recall IFN-γ secretion by restimulated peripheral blood mononuclear cells in CNPs-KAg compared to control KAg vaccinates were observed. In CNPs-KAg vaccinated pigs challenged with heterologous virus reduced severity of macroscopic and microscopic influenza-associated pulmonary lesions were observed. Importantly, the infectious SwIAV titers in nasal swabs [days post-challenge (DPC) 4] and BAL fluid (DPC 6) were significantly ( p  influenza nanovaccine may be an ideal candidate vaccine for use in pigs, and pig is a

Prior infection of chickens with H1N1 or H1N2 avian influenza elicits partial heterologous protection against highly pathogenic H5N1.

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Nfon, Charles; Berhane, Yohannes; Pasick, John; Embury-Hyatt, Carissa; Kobinger, Gary; Kobasa, Darwyn; Babiuk, Shawn

2012-01-01

There is a critical need to have vaccines that can protect against emerging pandemic influenza viruses. Commonly used influenza vaccines are killed whole virus that protect against homologous and not heterologous virus. Using chickens we have explored the possibility of using live low pathogenic avian influenza (LPAI) A/goose/AB/223/2005 H1N1 or A/WBS/MB/325/2006 H1N2 to induce immunity against heterologous highly pathogenic avian influenza (HPAI) A/chicken/Vietnam/14/2005 H5N1. H1N1 and H1N2 replicated in chickens but did not cause clinical disease. Following infection, chickens developed nucleoprotein and H1 specific antibodies, and reduced H5N1 plaque size in vitro in the absence of H5 neutralizing antibodies at 21 days post infection (DPI). In addition, heterologous cell mediated immunity (CMI) was demonstrated by antigen-specific proliferation and IFN-γ secretion in PBMCs re-stimulated with H5N1 antigen. Following H5N1 challenge of both pre-infected and naïve controls chickens housed together, all naïve chickens developed acute disease and died while H1N1 or H1N2 pre-infected chickens had reduced clinical disease and 70-80% survived. H1N1 or H1N2 pre-infected chickens were also challenged with H5N1 and naïve chickens placed in the same room one day later. All pre-infected birds were protected from H5N1 challenge but shed infectious virus to naïve contact chickens. However, disease onset, severity and mortality was reduced and delayed in the naïve contacts compared to directly inoculated naïve controls. These results indicate that prior infection with LPAI virus can generate heterologous protection against HPAI H5N1 in the absence of specific H5 antibody.

Prior infection of chickens with H1N1 or H1N2 avian influenza elicits partial heterologous protection against highly pathogenic H5N1.

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Charles Nfon

Full Text Available There is a critical need to have vaccines that can protect against emerging pandemic influenza viruses. Commonly used influenza vaccines are killed whole virus that protect against homologous and not heterologous virus. Using chickens we have explored the possibility of using live low pathogenic avian influenza (LPAI A/goose/AB/223/2005 H1N1 or A/WBS/MB/325/2006 H1N2 to induce immunity against heterologous highly pathogenic avian influenza (HPAI A/chicken/Vietnam/14/2005 H5N1. H1N1 and H1N2 replicated in chickens but did not cause clinical disease. Following infection, chickens developed nucleoprotein and H1 specific antibodies, and reduced H5N1 plaque size in vitro in the absence of H5 neutralizing antibodies at 21 days post infection (DPI. In addition, heterologous cell mediated immunity (CMI was demonstrated by antigen-specific proliferation and IFN-γ secretion in PBMCs re-stimulated with H5N1 antigen. Following H5N1 challenge of both pre-infected and naïve controls chickens housed together, all naïve chickens developed acute disease and died while H1N1 or H1N2 pre-infected chickens had reduced clinical disease and 70-80% survived. H1N1 or H1N2 pre-infected chickens were also challenged with H5N1 and naïve chickens placed in the same room one day later. All pre-infected birds were protected from H5N1 challenge but shed infectious virus to naïve contact chickens. However, disease onset, severity and mortality was reduced and delayed in the naïve contacts compared to directly inoculated naïve controls. These results indicate that prior infection with LPAI virus can generate heterologous protection against HPAI H5N1 in the absence of specific H5 antibody.

TLR1/2 activation during heterologous prime-boost vaccination (DNA-MVA enhances CD8+ T Cell responses providing protection against Leishmania (Viannia.

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Asha Jayakumar

2011-06-01

Full Text Available Leishmania (Viannia parasites present particular challenges, as human and murine immune responses to infection are distinct from other Leishmania species, indicating a unique interaction with the host. Further, vaccination studies utilizing small animal models indicate that modalities and antigens that prevent infection by other Leishmania species are generally not protective.Using a newly developed mouse model of chronic L. (Viannia panamensis infection and the heterologous DNA prime - modified vaccinia virus Ankara (MVA boost vaccination modality, we examined whether the conserved vaccine candidate antigen tryparedoxin peroxidase (TRYP could provide protection against infection/disease.Heterologous prime - boost (DNA/MVA vaccination utilizing TRYP antigen can provide protection against disease caused by L. (V. panamensis. However, protection is dependent on modulating the innate immune response using the TLR1/2 agonist Pam3CSK4 during DNA priming. Prime-boost vaccination using DNA alone fails to protect. Prior to infection protectively vaccinated mice exhibit augmented CD4 and CD8 IFNγ and memory responses as well as decreased IL-10 and IL-13 responses. IL-13 and IL-10 have been shown to be independently critical for disease in this model. CD8 T cells have an essential role in mediating host defense, as CD8 depletion reversed protection in the vaccinated mice; vaccinated mice depleted of CD4 T cells remained protected. Hence, vaccine-induced protection is dependent upon TLR1/2 activation instructing the generation of antigen specific CD8 cells and restricting IL-13 and IL-10 responses.Given the general effectiveness of prime-boost vaccination, the recalcitrance of Leishmania (Viannia to vaccine approaches effective against other species of Leishmania is again evident. However, prime-boost vaccination modality can with modulation induce protective responses, indicating that the delivery system is critical. Moreover, these results suggest that

Intranasal boosting with an adenovirus-vectored vaccine markedly enhances protection by parenteral Mycobacterium bovis BCG immunization against pulmonary tuberculosis.

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Santosuosso, Michael; McCormick, Sarah; Zhang, Xizhong; Zganiacz, Anna; Xing, Zhou

2006-08-01

Parenterally administered Mycobacterium bovis BCG vaccine confers only limited immune protection from pulmonary tuberculosis in humans. There is a need for developing effective boosting vaccination strategies. We examined a heterologous prime-boost regimen utilizing BCG as a prime vaccine and our recently described adenoviral vector expressing Ag85A (AdAg85A) as a boost vaccine. Since we recently demonstrated that a single intranasal but not intramuscular immunization with AdAg85A was able to induce potent protection from pulmonary Mycobacterium tuberculosis challenge in a mouse model, we compared the protective effects of parenteral and mucosal booster immunizations following subcutaneous BCG priming. Protection by BCG prime immunization was not effectively boosted by subcutaneous BCG or intramuscular AdAg85A. In contrast, protection by BCG priming was remarkably boosted by intranasal AdAg85A. Such enhanced protection by intranasal AdAg85A was correlated to the numbers of gamma interferon-positive CD4 and CD8 T cells residing in the airway lumen of the lung. Our study demonstrates that intranasal administration of AdAg85A represents an effective way to boost immune protection by parenteral BCG vaccination.

Mucosal Immunity and Protective Efficacy of Intranasal Inactivated Influenza Vaccine Is Improved by Chitosan Nanoparticle Delivery in Pigs

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Santosh Dhakal

2018-05-01

Full Text Available Annually, swine influenza A virus (SwIAV causes severe economic loss to swine industry. Currently used inactivated SwIAV vaccines administered by intramuscular injection provide homologous protection, but limited heterologous protection against constantly evolving field viruses, attributable to the induction of inadequate levels of mucosal IgA and cellular immune responses in the respiratory tract. A novel vaccine delivery platform using mucoadhesive chitosan nanoparticles (CNPs administered through intranasal (IN route has the potential to elicit strong mucosal and systemic immune responses in pigs. In this study, we evaluated the immune responses and cross-protective efficacy of IN chitosan encapsulated inactivated SwIAV vaccine in pigs. Killed SwIAV H1N2 (δ-lineage antigens (KAg were encapsulated in chitosan polymer-based nanoparticles (CNPs-KAg. The candidate vaccine was administered twice IN as mist to nursery pigs. Vaccinates and controls were then challenged with a zoonotic and virulent heterologous SwIAV H1N1 (γ-lineage. Pigs vaccinated with CNPs-KAg exhibited an enhanced IgG serum antibody and mucosal secretory IgA antibody responses in nasal swabs, bronchoalveolar lavage (BAL fluids, and lung lysates that were reactive against homologous (H1N2, heterologous (H1N1, and heterosubtypic (H3N2 influenza A virus strains. Prior to challenge, an increased frequency of cytotoxic T lymphocytes, antigen-specific lymphocyte proliferation, and recall IFN-γ secretion by restimulated peripheral blood mononuclear cells in CNPs-KAg compared to control KAg vaccinates were observed. In CNPs-KAg vaccinated pigs challenged with heterologous virus reduced severity of macroscopic and microscopic influenza-associated pulmonary lesions were observed. Importantly, the infectious SwIAV titers in nasal swabs [days post-challenge (DPC 4] and BAL fluid (DPC 6 were significantly (p < 0.05 reduced in CNPs-KAg vaccinates but not in KAg vaccinates when compared

Neonatal BCG vaccination is associated with enhanced T-helper 1 immune responses to heterologous infant vaccines.

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Libraty, Daniel H; Zhang, Lei; Woda, Marcia; Acosta, Luz P; Obcena, Anamae; Brion, Job D; Capeding, Rosario Z

2014-01-01

Neonatal Bacille Calmette Guérin (BCG) vaccination has been reported to have beneficial effects beyond preventing infantile tuberculous meningitis and miliary disease. We hypothesized that BCG vaccine given at birth would enhance T-helper 1 (Th1) immune responses to the first vaccines given later in infancy. We conducted a nested case-control study of neonatal BCG vaccination and its heterologous Th1 immune effects in 2-3 months old infants. BCG vaccination at birth was associated with an increased frequency of interferon-γ (IFN-γ) producing spot-forming cells (SFC) to tetanus toxoid 2-3 months later. The frequency of IFN-γ producing SFC to polioviruses 1-3 also trended higher among infants who received BCG vaccination at birth. The frequency of IFN-γ+/tumor necrosis factor-α (TNF-α)+CD45RO+CD4+ T-cells upon stimulation with phorbol myristate acetate (PMA)/Ionomycin was higher in 2-3 months old infants who received BCG vaccination at birth compared to those who did not. The circulating frequency of forkhead box P3 (FoxP3)+ CD45RO+ regulatory CD4+ T-cells also trended lower in these infants. Neonatal BCG vaccination is associated with heterologous Th1 immune effects 2-3 months later.

Oral or parenteral administration of replication-deficient adenoviruses expressing the measles virus haemagglutinin and fusion proteins: protective immune responses in rodents.

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Fooks, A R; Jeevarajah, D; Lee, J; Warnes, A; Niewiesk, S; ter Meulen, V; Stephenson, J R; Clegg, J C

1998-05-01

The genes encoding the measles virus (MV) haemagglutinin (H) and fusion (F) proteins were placed under the control of the human cytomegalovirus immediate early promoter in a replication-deficient adenovirus vector. Immunofluorescence and radioimmune precipitation demonstrated the synthesis of each protein and biological activity was confirmed by the detection of haemadsorption and fusion activities in infected cells. Oral as well as parenteral administration of the H-expressing recombinant adenovirus elicited a significant protective response in mice challenged with MV. While the F-expressing adenovirus failed to protect mice, cotton rats immunized with either the H- or F-expressing recombinant showed reduced MV replication in the lungs. Antibodies elicited in mice following immunization with either recombinant had no in vitro neutralizing activity, suggesting a protective mechanism involving a cell-mediated immune response. This study demonstrates the feasibility of using oral administration of adenovirus recombinants to induce protective responses to heterologous proteins.

Neonatal BCG vaccination is associated with enhanced T-helper 1 immune responses to heterologous infant vaccines

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Daniel H. Libraty

2014-01-01

Full Text Available Neonatal Bacille Calmette Guérin (BCG vaccination has been reported to have beneficial effects beyond preventing infantile tuberculous meningitis and miliary disease. We hypothesized that BCG vaccine given at birth would enhance T-helper 1 (Th1 immune responses to the first vaccines given later in infancy. We conducted a nested case-control study of neonatal BCG vaccination and its heterologous Th1 immune effects in 2–3 months old infants. BCG vaccination at birth was associated with an increased frequency of interferon-γ (IFN-γ producing spot-forming cells (SFC to tetanus toxoid 2–3 months later. The frequency of IFN-γ producing SFC to polioviruses 1–3 also trended higher among infants who received BCG vaccination at birth. The frequency of IFN-γ+/tumor necrosis factor-α (TNF-α+CD45RO+CD4+ T-cells upon stimulation with phorbol myristate acetate (PMA/Ionomycin was higher in 2–3 months old infants who received BCG vaccination at birth compared to those who did not. The circulating frequency of forkhead box P3 (FoxP3+ CD45RO+ regulatory CD4+ T-cells also trended lower in these infants. Neonatal BCG vaccination is associated with heterologous Th1 immune effects 2–3 months later.

A prime-boost vaccination strategy using attenuated Salmonella typhimurium and a replication-deficient recombinant adenovirus vector elicits protective immunity against human respiratory syncytial virus.

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Fu, Yuan-Hui; He, Jin-Sheng; Wang, Xiao-Bo; Zheng, Xian-Xian; Wu, Qiang; Xie, Can; Zhang, Mei; Wei, Wei; Tang, Qian; Song, Jing-Dong; Qu, Jian-Guo; Hong, Tao

2010-04-23

Human respiratory syncytial virus (RSV), for which no clinically approved vaccine is available yet, is globally a serious pediatric pathogen of the lower respiratory tract. Several approaches have been used to develop vaccines against RSV, but none of these have been approved for use in humans. An efficient vaccine-enhancing strategy for RSV is still urgently needed. We found previously that oral SL7207/pcDNA3.1/F and intranasal FGAd/F were able to induce an effective protective immune response against RSV. The heterologous prime-boost immunization regime has been reported recently to be an efficient vaccine-enhancing strategy. Therefore, we investigated the ability of an oral SL7207/pcDNA3.1/F prime and intranasal (i.n.) FGAd/F boost regimen to generate immune responses to RSV. The SL7207/pcDNA3.1/F prime-FGAd/F boost regimen generated stronger RSV-specific humoral and mucosal immune responses in BALB/c mice than the oral SL7207/pcDNA3.1/F regimen alone, and stronger specific cellular immune responses than the i.n. FGAd/F regimen alone. Histopathological analysis showed an increased efficacy against RSV challenge by the heterologous prime-boost regimen. These results suggest that such a heterologous prime-boost strategy can enhance the efficacy of either the SL7207 or the FGAd vector regimen in generating immune responses in BALB/c mice. 2010 Elsevier Inc. All rights reserved.

Immunogenicity and Protective Efficacy of Brugia malayi Heavy Chain Myosin as Homologous DNA, Protein and Heterologous DNA/Protein Prime Boost Vaccine in Rodent Model.

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Jyoti Gupta

Full Text Available We earlier demonstrated the immunoprophylactic efficacy of recombinant heavy chain myosin (Bm-Myo of Brugia malayi (B. malayi in rodent models. In the current study, further attempts have been made to improve this efficacy by employing alternate approaches such as homologous DNA (pcD-Myo and heterologous DNA/protein prime boost (pcD-Myo+Bm-Myo in BALB/c mouse model. The gene bm-myo was cloned in a mammalian expression vector pcDNA 3.1(+ and protein expression was confirmed in mammalian Vero cell line. A significant degree of protection (79.2%±2.32 against L3 challenge in pcD-Myo+Bm-Myo immunized group was observed which was much higher than that exerted by Bm-Myo (66.6%±2.23 and pcD-Myo (41.6%±2.45. In the heterologous immunized group, the percentage of peritoneal leukocytes such as macrophages, neutrophils, B cells and T cells marginally increased and their population augmented further significantly following L3 challenge. pcD-Myo+Bm-Myo immunization elicited robust cellular and humoral immune responses as compared to pcD-Myo and Bm-Myo groups as evidenced by an increased accumulation of CD4+, CD8+ T cells and CD19+ B cells in the mouse spleen and activation of peritoneal macrophages. Though immunized animals produced antigen-specific IgG antibodies and isotypes, sera of mice receiving pcD-Myo+Bm-Myo or Bm-Myo developed much higher antibody levels than other groups and there was profound antibody-dependent cellular adhesion and cytotoxicity (ADCC to B. malayi infective larvae (L3. pcD-Myo+Bm-Myo as well as Bm-Myo mice generated a mixed T helper cell phenotype as evidenced by the production of both pro-inflammatory (IL-2, IFN-γ and anti-inflammatory (IL-4, IL-10 cytokines. Mice receiving pcD-Myo on contrary displayed a polarized pro-inflammatory immune response. The findings suggest that the priming of animals with DNA followed by protein booster generates heightened and mixed pro- and anti-inflammatory immune responses that are capable of

Commensal–dendritic-cell interaction specifies a unique protective skin immune signature

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Naik, Shruti; Bouladoux, Nicolas; Linehan, Jonathan L.; Han, Seong-Ji; Harrison, Oliver J.; Wilhelm, Christoph; Conlan, Sean; Himmelfarb, Sarah; Byrd, Allyson L.; Deming, Clayton; Quinones, Mariam; Brenchley, Jason M.; Kong, Heidi H.; Tussiwand, Roxanne; Murphy, Kenneth M.; Merad, Miriam; Segre, Julia A; Belkaid, Yasmine

2015-01-01

The skin represents the primary interface between the host and the environment. This organ is also home to trillions of microorganisms that play an important role in tissue homeostasis and local immunity1–4. Skin microbial communities are highly diverse and can be remodelled over time or in response to environmental challenges5–7. How, in the context of this complexity, individual commensal microorganisms may differentially modulate skin immunity and the consequences of these responses for tissue physiology remains unclear. Here we show that defined commensals dominantly affect skin immunity and identify the cellular mediators involved in this specification. In particular, colonization with Staphylococcus epidermidis induces IL-17A+ CD8+ T cells that home to the epidermis, enhance innate barrier immunity and limit pathogen invasion. Commensal-specific T-cell responses result from the coordinated action of skin-resident dendritic cell subsets and are not associated with inflammation, revealing that tissue-resident cells are poised to sense and respond to alterations in microbial communities. This interaction may represent an evolutionary means by which the skin immune system uses fluctuating commensal signals to calibrate barrier immunity and provide heterologous protection against invasive pathogens. These findings reveal that the skin immune landscape is a highly dynamic environment that can be rapidly and specifically remodelled by encounters with defined commensals, findings that have profound implications for our understanding of tissue-specific immunity and pathologies. PMID:25539086

Homologous and Heterologous Protection of Nonhuman Primates by Ebola and Sudan Virus-Like Particles

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Warfield, Kelly L.; Dye, John M.; Wells, Jay B.; Unfer, Robert C.; Holtsberg, Frederick W.; Shulenin, Sergey; Vu, Hong; Swenson, Dana L.; Bavari, Sina; Aman, M. Javad

2015-01-01

Filoviruses cause hemorrhagic fever resulting in significant morbidity and mortality in humans. Several vaccine platforms that include multiple virus-vectored approaches and virus-like particles (VLPs) have shown efficacy in nonhuman primates. Previous studies have shown protection of cynomolgus macaques against homologous infection for Ebola virus (EBOV) and Marburg virus (MARV) following a three-dose vaccine regimen of EBOV or MARV VLPs, as well as heterologous protection against Ravn Virus (RAVV) following vaccination with MARV VLPs. The objectives of the current studies were to determine the minimum number of vaccine doses required for protection (using EBOV as the test system) and then demonstrate protection against Sudan virus (SUDV) and Taï Forest virus (TAFV). Using the EBOV nonhuman primate model, we show that one or two doses of VLP vaccine can confer protection from lethal infection. VLPs containing the SUDV glycoprotein, nucleoprotein and VP40 matrix protein provide complete protection against lethal SUDV infection in macaques. Finally, we demonstrate protective efficacy mediated by EBOV, but not SUDV, VLPs against TAFV; this is the first demonstration of complete cross-filovirus protection using a single component heterologous vaccine within the Ebolavirus genus. Along with our previous results, this observation provides strong evidence that it will be possible to develop and administer a broad-spectrum VLP-based vaccine that will protect against multiple filoviruses by combining only three EBOV, SUDV and MARV components. PMID:25793502

Homologous and heterologous protection of nonhuman primates by Ebola and Sudan virus-like particles.

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Kelly L Warfield

Full Text Available Filoviruses cause hemorrhagic fever resulting in significant morbidity and mortality in humans. Several vaccine platforms that include multiple virus-vectored approaches and virus-like particles (VLPs have shown efficacy in nonhuman primates. Previous studies have shown protection of cynomolgus macaques against homologous infection for Ebola virus (EBOV and Marburg virus (MARV following a three-dose vaccine regimen of EBOV or MARV VLPs, as well as heterologous protection against Ravn Virus (RAVV following vaccination with MARV VLPs. The objectives of the current studies were to determine the minimum number of vaccine doses required for protection (using EBOV as the test system and then demonstrate protection against Sudan virus (SUDV and Taï Forest virus (TAFV. Using the EBOV nonhuman primate model, we show that one or two doses of VLP vaccine can confer protection from lethal infection. VLPs containing the SUDV glycoprotein, nucleoprotein and VP40 matrix protein provide complete protection against lethal SUDV infection in macaques. Finally, we demonstrate protective efficacy mediated by EBOV, but not SUDV, VLPs against TAFV; this is the first demonstration of complete cross-filovirus protection using a single component heterologous vaccine within the Ebolavirus genus. Along with our previous results, this observation provides strong evidence that it will be possible to develop and administer a broad-spectrum VLP-based vaccine that will protect against multiple filoviruses by combining only three EBOV, SUDV and MARV components.

Recombinant vaccines against T. gondii: comparison between homologous and heterologous vaccination protocols using two viral vectors expressing SAG1.

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Mendes, Érica Araújo; Fonseca, Flavio G; Casério, Bárbara M; Colina, Janaína P; Gazzinelli, Ricardo Tostes; Caetano, Braulia C

2013-01-01

The use of recombinant viral vectors expressing T. gondii antigens is a safe and efficient approach to induce immune response against the parasite and a valuable tool for vaccine development. We have previously protected mice from toxoplasmosis by immunizing the animals with an adenovirus expressing the protein SAG1 (AdSAG1) of T. gondii. We are now looking for ways to improve the vaccination strategy and enhance protection. One limitation of homologous vaccinations (sequential doses of the same vector) is induction of anti-vector immune response that blocks cell transduction, restricts transgene expression and, consequently, compromises the overall outcome of vaccination. One way to avert the effects of anti-vector response is to use different viruses in prime and boost (heterologous vaccination). Bearing this in mind, we generated a modified Vaccinia Virus Ankara encoding SAG1 (MVASAG1), to be tested as boost agent after prime with AdSAG1. Although minor differences were observed in the magnitude of the anti-SAG1 immune response induced by each vaccination protocol, the heterologous immunization with AdSAG1 followed by MVASAG1 resulted in improved capacity to control brain cyst formation in a model of chronic toxoplasmosis in C57BL/6 mice.

Recombinant vaccines against T. gondii: comparison between homologous and heterologous vaccination protocols using two viral vectors expressing SAG1.

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Érica Araújo Mendes

Full Text Available The use of recombinant viral vectors expressing T. gondii antigens is a safe and efficient approach to induce immune response against the parasite and a valuable tool for vaccine development. We have previously protected mice from toxoplasmosis by immunizing the animals with an adenovirus expressing the protein SAG1 (AdSAG1 of T. gondii. We are now looking for ways to improve the vaccination strategy and enhance protection. One limitation of homologous vaccinations (sequential doses of the same vector is induction of anti-vector immune response that blocks cell transduction, restricts transgene expression and, consequently, compromises the overall outcome of vaccination. One way to avert the effects of anti-vector response is to use different viruses in prime and boost (heterologous vaccination. Bearing this in mind, we generated a modified Vaccinia Virus Ankara encoding SAG1 (MVASAG1, to be tested as boost agent after prime with AdSAG1. Although minor differences were observed in the magnitude of the anti-SAG1 immune response induced by each vaccination protocol, the heterologous immunization with AdSAG1 followed by MVASAG1 resulted in improved capacity to control brain cyst formation in a model of chronic toxoplasmosis in C57BL/6 mice.

Vaccination of mice using the West Nile virus E-protein in a DNA prime-protein boost strategy stimulates cell-mediated immunity and protects mice against a lethal challenge.

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Marina De Filette

Full Text Available West Nile virus (WNV is a mosquito-borne flavivirus that is endemic in Africa, the Middle East, Europe and the United States. There is currently no antiviral treatment or human vaccine available to treat or prevent WNV infection. DNA plasmid-based vaccines represent a new approach for controlling infectious diseases. In rodents, DNA vaccines have been shown to induce B cell and cytotoxic T cell responses and protect against a wide range of infections. In this study, we formulated a plasmid DNA vector expressing the ectodomain of the E-protein of WNV into nanoparticles by using linear polyethyleneimine (lPEI covalently bound to mannose and examined the potential of this vaccine to protect against lethal WNV infection in mice. Mice were immunized twice (prime--boost regime with the WNV DNA vaccine formulated with lPEI-mannose using different administration routes (intramuscular, intradermal and topical. In parallel a heterologous boost with purified recombinant WNV envelope (E protein was evaluated. While no significant E-protein specific humoral response was generated after DNA immunization, protein boosting of DNA-primed mice resulted in a marked increase in total neutralizing antibody titer. In addition, E-specific IL-4 T-cell immune responses were detected by ELISPOT after protein boost and CD8(+ specific IFN-γ expression was observed by flow cytometry. Challenge experiments using the heterologous immunization regime revealed protective immunity to homologous and virulent WNV infection.

Recombinant Listeria monocytogenes as a Live Vaccine Vehicle for the Induction of Protective Anti-Viral Cell-Mediated Immunity

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Shen, Hao; Slifka, Mark K.; Matloubian, Mehrdad; Jensen, Eric R.; Ahmed, Rafi; Miller, Jeff F.

1995-04-01

Listeria monocytogenes (LM) is a Gram-positive bacterium that is able to enter host cells, escape from the endocytic vesicle, multiply within the cytoplasm, and spread directly from cell to cell without encountering the extracellular milieu. The ability of LM to gain access to the host cell cytosol allows proteins secreted by the bacterium to efficiently enter the pathway for major histocompatibility complex class I antigen processing and presentation. We have established a genetic system for expression and secretion of foreign antigens by recombinant strains, based on stable site-specific integration of expression cassettes into the LM genome. The ability of LM recombinants to induce protective immunity against a heterologous pathogen was demonstrated with lymphocytic choriomeningitis virus (LCMV). LM strains expressing the entire LCMV nucleoprotein or an H-2L^d-restricted nucleoprotein epitope (aa 118-126) were constructed. Immunization of mice with LM vaccine strains conferred protection against challenge with virulent strains of LCMV that otherwise establish chronic infection in naive adult mice. In vivo depletion of CD8^+ T cells from vaccinated mice abrogated their ability to clear viral infection, showing that protective anti-viral immunity was due to CD8^+ T cells.

Protective efficacy of an inactivated Eurasian avian-like H1N1 swine influenza vaccine against homologous H1N1 and heterologous H1N1 and H1N2 viruses in mice.

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Sui, Jinyu; Yang, Dawei; Qiao, Chuanling; Xu, Huiyang; Xu, Bangfeng; Wu, Yunpu; Yang, Huanliang; Chen, Yan; Chen, Hualan

2016-07-19

Eurasian avian-like H1N1 (EA H1N1) swine influenza viruses are prevalent in pigs in Europe and Asia, but occasionally cause human infection, which raises concern about their pandemic potential. Here, we produced a whole-virus inactivated vaccine with an EA H1N1 strain (A/swine/Guangxi/18/2011, SW/GX/18/11) and evaluated its efficacy against homologous H1N1 and heterologous H1N1 and H1N2 influenza viruses in mice. A strong humoral immune response, which we measured by hemagglutination inhibition (HI) and virus neutralization (VN), was induced in the vaccine-inoculated mice upon challenge. The inactivated SW/GX/18/11 vaccine provided complete protection against challenge with homologous SW/GX/18/11 virus in mice and provided effective protection against challenge with heterologous H1N1 and H1N2 viruses with distinctive genomic combinations. Our findings suggest that this EA H1N1 vaccine can provide protection against both homologous H1N1 and heterologous H1N1 or H1N2 virus infection. As such, it is an excellent vaccine candidate to prevent H1N1 swine influenza. Copyright © 2016 Elsevier Ltd. All rights reserved.

Heterologous Two-Dose Vaccination with Simian Adenovirus and Poxvirus Vectors Elicits Long-Lasting Cellular Immunity to Influenza Virus A in Healthy Adults

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L. Coughlan

2018-03-01

Full Text Available Background: T-cell responses against highly conserved influenza antigens have been previously associated with protection. However, these immune responses are poorly maintained following recovery from influenza infection and are not boosted by inactivated influenza vaccines. We have previously demonstrated the safety and immunogenicity of two viral vectored vaccines, modified vaccinia virus Ankara (MVA and the chimpanzee adenovirus ChAdOx1 expressing conserved influenza virus antigens, nucleoprotein (NP and matrix protein-1 (M1. We now report on the safety and long-term immunogenicity of multiple combination regimes of these vaccines in young and older adults. Methods: We conducted a Phase I open-label, randomized, multi-center study in 49 subjects aged 18–46 years and 24 subjects aged 50 years or over. Following vaccination, adverse events were recorded and the kinetics of the T cell response determined at multiple time points for up to 18 months. Findings: Both vaccines were well tolerated. A two dose heterologous vaccination regimen significantly increased the magnitude of pre-existing T-cell responses to NP and M1 after both doses in young and older adults. The fold-increase and peak immune responses after a single MVA-NP + M1 vaccination was significantly higher compared to ChAdOx1 NP + M1. In a mixed regression model, T-cell responses over 18 months were significantly higher following the two dose vaccination regimen of MVA/ChAdOx1 NP + M1. Interpretation: A two dose heterologous vaccination regimen of MVA/ChAdOx1 NP + M1 was safe and immunogenic in young and older adults, offering a promising vaccination strategy for inducing long-term broadly cross-reactive protection against influenza A. Funding Source: Medical Research Council UK, NIHR BMRC Oxford. Keywords: Influenza, T-cell responses, Influenza vaccines, Viral vectors, Adults, Older adults

Protection against syphilis correlates with specificity of antibodies to the variable regions of Treponema pallidum repeat protein K.

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Morgan, Cecilia A; Lukehart, Sheila A; Van Voorhis, Wesley C

2003-10-01

Syphilis has been recognized as a disease since the late 1400s, yet there is no practical vaccine available. One impediment to the development of a vaccine is the lack of understanding of multiple reinfections in humans despite the development of robust immune responses during the first episode. It has been shown that the Treponema pallidum repeat protein K (TprK) differs in seven discrete variable (V) regions in isolates and that the antibody response during infection is directed to these V regions. Immunization with TprK confers significant protection against infection with the homologous strain. We hypothesize that the antigenic diversity of TprK is involved in immune evasion, which contributes to the lack of heterologous protection. Here, using the rabbit model, we show a correlation between limited heterologous protection and tprK diversity in the challenge inoculum. We demonstrate that antibody responses to the V regions of one TprK molecule show limited cross-reactivity with heterologous TprK V regions.

A polyvalent influenza A DNA vaccine induces heterologous immunity and protects pigs against pandemic A(H1N1)pdm09 virus infection

DEFF Research Database (Denmark)

Bragstad, Karoline; Vinner, Lasse; Hansen, Mette Sif

2013-01-01

seasonal and emerging influenza viruses. We have developed an alternative influenza vaccine based on DNA expressing selected influenza proteins of pandemic and seasonal origin. In the current study, we investigated the protection of a polyvalent influenza DNA vaccine approach in pigs. We immunised pigs...... intradermally with a combination of influenza DNA vaccine components based on the pandemic 1918 H1N1 (M and NP genes), pandemic 2009 H1N1pdm09 (HA and NA genes) and seasonal 2005 H3N2 genes (HA and NA genes) and investigated the protection against infection with virus both homologous and heterologous to the DNA...... of this DNA vaccine to limit virus shedding may have an impact on virus spread among pigs which could possibly extend to humans as well, thereby diminishing the risk for epidemics and pandemics to evolve....

A heterologous prime-boost Ebola virus vaccine regimen induces durable neutralizing antibody response and prevents Ebola virus-like particle entry in mice.

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Chen, Tan; Li, Dapeng; Song, Yufeng; Yang, Xi; Liu, Qingwei; Jin, Xia; Zhou, Dongming; Huang, Zhong

2017-09-01

Ebola virus (EBOV) is one of the most virulent pathogens known to humans. Neutralizing antibodies play a major role in the protection against EBOV infections. Thus, an EBOV vaccine capable of inducing a long-lasting neutralizing antibody response is highly desirable. We report here that a heterologous prime-boost vaccine regimen can elicit durable EBOV-neutralizing antibody response in mice. A chimpanzee serotype 7 adenovirus expressing EBOV GP (denoted AdC7-GP) was generated and used for priming. A truncated version of EBOV GP1 protein (denoted GP1t) was produced at high levels in Drosophila S2 cells and used for boosting. Mouse immunization studies showed that the AdC7-GP prime/GP1t boost vaccine regimen was more potent in eliciting neutralizing antibodies than either the AdC7-GP or GP1t alone. Neutralizing antibodies induced by the heterologous prime-boost regimen sustained at high titers for at least 18 weeks after immunization. Significantly, in vivo challenge studies revealed that the entry of reporter EBOV-like particles was efficiently blocked in mice receiving the heterologous prime-boost regimen even at 18 weeks after the final dose of immunization. These results suggest that this novel AdC7-GP prime/GP1t boost regimen represents an EBOV vaccine approach capable of establishing long-term protection, and therefore warrants further development. Copyright © 2017 Elsevier B.V. All rights reserved.

An initial examination of the potential role of T-cell immunity in protection against feline immunodeficiency virus (FIV) infection.

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Aranyos, Alek M; Roff, Shannon R; Pu, Ruiyu; Owen, Jennifer L; Coleman, James K; Yamamoto, Janet K

2016-03-14

The importance of vaccine-induced T-cell immunity in conferring protection with prototype and commercial FIV vaccines is still unclear. Current studies performed adoptive transfer of T cells from prototype FIV-vaccinated cats to partial-to-complete feline leukocyte antigen (FLA)-matched cats a day before either homologous FIVPet or heterologous-subtype pathogenic FIVFC1 challenge. Adoptive-transfer (A-T) conferred a protection rate of 87% (13 of 15, p 13 × 10(6) cells were required for A-T protection against FIVFC1 strain, reported to be a highly pathogenic virus resistant to vaccine-induced neutralizing-antibodies. The addition of FLA-matched B cells alone was not protective. The poor quality of the anti-FIV T-cell immunity induced by the vaccine likely contributed to the lack of protection in an FLA-matched recipient against FIVFC1. The quality of the immune response was determined by the presence of high mRNA levels of cytolysin (perforin) and cytotoxins (granzymes A, B, and H) and T helper-1 cytokines (interferon-γ [IFNγ] and IL2). Increased cytokine, cytolysin and cytotoxin production was detected in the donors which conferred protection in A-T studies. In addition, the CD4(+) and CD8(+) T-cell proliferation and/or IFNγ responses to FIV p24 and reverse transcriptase increased with each year in cats receiving 1X-3X vaccine boosts over 4 years. These studies demonstrate that anti-FIV T-cell immunity induced by vaccination with a dual-subtype FIV vaccine is essential for prophylactic protection against AIDS lentiviruses such as FIV and potentially HIV-1. Copyright © 2016 Elsevier Ltd. All rights reserved.

Live recombinant Salmonella Typhi vaccines constructed to investigate the role of rpoS in eliciting immunity to a heterologous antigen.

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Huoying Shi

2010-06-01

Full Text Available We hypothesized that the immunogenicity of live Salmonella enterica serovar Typhi vaccines expressing heterologous antigens depends, at least in part, on its rpoS status. As part of our project to develop a recombinant attenuated S. Typhi vaccine (RASTyV to prevent pneumococcal diseases in infants and children, we constructed three RASTyV strains synthesizing the Streptococcus pneumoniae surface protein PspA to test this hypothesis. Each vector strain carried ten engineered mutations designed to optimize safety and immunogenicity. Two S. Typhi vector strains (chi9639 and chi9640 were derived from the rpoS mutant strain Ty2 and one (chi9633 from the RpoS(+ strain ISP1820. In chi9640, the nonfunctional rpoS gene was replaced with the functional rpoS gene from ISP1820. Plasmid pYA4088, encoding a secreted form of PspA, was moved into the three vector strains. The resulting RASTyV strains were evaluated for safety in vitro and for immunogenicity in mice. All three RASTyV strains were similar to the live attenuated typhoid vaccine Ty21a in their ability to survive in human blood and human monocytes. They were more sensitive to complement and were less able to survive and persist in sewage and surface water than their wild-type counterparts. Adult mice intranasally immunized with any of the RASTyV strains developed immune responses against PspA and Salmonella antigens. The RpoS(+ vaccines induced a balanced Th1/Th2 immune response while the RpoS(- strain chi9639(pYA4088 induced a strong Th2 immune response. Immunization with any RASTyV provided protection against S. pneumoniae challenge; the RpoS(+ strain chi9640(pYA4088 provided significantly greater protection than the ISP1820 derivative, chi9633(pYA4088. In the pre-clinical setting, these strains exhibited a desirable balance between safety and immunogenicity and are currently being evaluated in a Phase 1 clinical trial to determine which of the three RASTyVs has the optimal safety and

Immune markers and correlates of protection for vaccine induced immune responses

DEFF Research Database (Denmark)

Thakur, Aneesh; Pedersen, Lasse Eggers; Jungersen, Gregers

2012-01-01

of an appropriate humoral response currently remain the best validated correlates of protective immunity after vaccination. Despite advancements in the field of immunology over the past few decades currently there are, however, no sufficiently validated immune correlates of vaccine induced protection against......-specific production of interferon-gamma (IFN-γ) has been promoted as a quantitative marker of protective cell-mediated immune responses over the past couple of decades. More recently, however, evidence from several infections has pointed towards the quality of the immune response, measured through increased levels...... of antigen-specific polyfunctional T cells capable of producing a triad of relevant cytokines, as a better correlate of sustained protective immunity against this type of infections. Also the possibilities to measure antigen-specific cytotoxic T cells (CTL) during infection or in response to vaccination...

Expression of H5 hemagglutinin vaccine antigen in common duckweed (Lemna minor) protects against H5N1 high pathogenicity avian influenza virus challenge in immunized chickens.

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Bertran, Kateri; Thomas, Colleen; Guo, Xuan; Bublot, Michel; Pritchard, Nikki; Regan, Jeffrey T; Cox, Kevin M; Gasdaska, John R; Dickey, Lynn F; Kapczynski, Darrell R; Swayne, David E

2015-07-09

A synthetic hemagglutinin (HA) gene from the highly pathogenic avian influenza (HPAI) virus A/chicken/Indonesia/7/2003 (H5N1) (Indo/03) was expressed in aquatic plant Lemna minor (rLemna-HA). In Experiment 1, efficacy of rLemna-HA was tested on birds immunized with 0.2μg or 2.3 μg HA and challenged with 10(6) mean chicken embryo infectious doses (EID50) of homologous virus strain. Both dosages of rLemna-HA conferred clinical protection and dramatically reduced viral shedding. Almost all the birds immunized with either dosage of rLemna-HA elicited HA antibody titers against Indo/03 antigen, suggesting an association between levels of anti-Indo/03 antibodies and protection. In Experiment 2, efficacy of rLemna-HA was tested on birds immunized with 0.9 μg or 2.2 μg HA and challenged with 10(6) EID50 of heterologous H5N1 virus strains A/chicken/Vietnam/NCVD-421/2010 (VN/10) or A/chicken/West Java/PWT-WIJ/2006 (PWT/06). Birds challenged with VN/10 exhibited 100% survival regardless of immunization dosage, while birds challenged with PWT/06 had 50% and 30% mortality at 0.9 μg HA and 2.2 μg HA, respectively. For each challenge virus, viral shedding titers from 2.2 μg HA vaccinated birds were significantly lower than those from 0.9μg HA vaccinated birds, and titers from both immunized groups were in turn significantly lower than those from sham vaccinated birds. Even if immunized birds elicited HA titers against the vaccine antigen Indo/03, only the groups challenged with VN/10 developed humoral immunity against the challenge antigen. None (rLemna-HA 0.9 μg HA) and 40% (rLemna-HA 2.2 μg HA) of the immunized birds challenged with PWT/06 elicited pre-challenge antibody titers, respectively. In conclusion, Lemna-expressed HA demonstrated complete protective immunity against homologous challenge and suboptimal protection against heterologous challenge, the latter being similar to results from inactivated whole virus vaccines. Transgenic duckweed-derived HA could be a

Efficacy Testing of H56 cDNA Tattoo Immunization against Tuberculosis in a Mouse Model.

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Platteel, Anouk C M; Nieuwenhuizen, Natalie E; Domaszewska, Teresa; Schürer, Stefanie; Zedler, Ulrike; Brinkmann, Volker; Sijts, Alice J A M; Kaufmann, Stefan H E

2017-01-01

Tuberculosis (TB), caused by Mycobacterium tuberculosis ( Mtb ), remains a global threat. The only approved vaccine against TB, Mycobacterium bovis bacillus Calmette-Guérin (BCG), provides insufficient protection and, being a live vaccine, can cause disseminated disease in immunocompromised individuals. Previously, we found that intradermal cDNA tattoo immunization with cDNA of tetanus toxoid fragment C domain 1 fused to cDNA of the fusion protein H56, comprising the Mtb antigens Ag85B, ESAT-6, and Rv2660c, induced antigen-specific CD8 + T cell responses in vivo . As cDNA tattoo immunization would be safer than a live vaccine in immunocompromised patients, we tested the protective efficacy of intradermal tattoo immunization against TB with H56 cDNA, as well as with H56_E, a construct optimized for epitope processing in a mouse model. As Mtb antigens can be used in combination with BCG to boost immune responses, we also tested the protective efficacy of heterologous prime-boost, using dermal tattoo immunization with H56_E cDNA to boost BCG immunization in mice. Dermal H56 and H56_E cDNA immunization induced H56-specific CD4 + and CD8 + T cell responses and Ag85B-specific IgG antibodies, but did not reduce bacterial loads, although immunization with H56_E ameliorated lung pathology. Both subcutaneous and intradermal immunization with BCG resulted in broad cellular immune responses, with increased frequencies of CD4 + T effector memory cells, T follicular helper cells, and germinal center B cells, and resulted in reduced bacterial loads and lung pathology. Heterologous vaccination with BCG/H56_E cDNA induced increased H56-specific CD4 + and CD8 + T cell cytokine responses compared to vaccination with BCG alone, and lung pathology was significantly decreased in BCG/H56_E cDNA immunized mice compared to unvaccinated controls. However, bacterial loads were not decreased after heterologous vaccination compared to BCG alone. CD4 + T cells responding to Ag85B- and ESAT-6

Trained innate immunity as underlying mechanism for the long-term, nonspecific effects of vaccines

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Blok, Bastiaan A; Arts, Rob J W; van Crevel, Reinout

2015-01-01

An increasing body of evidence shows that the innate immune system has adaptive characteristics that involve a heterologous memory of past insults. Both experimental models and proof-of-principle clinical trials show that innate immune cells, such as monocytes, macrophages, and NK cells, can...... provide protection against certain infections in vaccination models independently of lymphocytes. This process is regulated through epigenetic reprogramming of innate immune cells and has been termed "trained immunity." It has been hypothesized that induction of trained immunity is responsible...... for the protective, nonspecific effects induced by vaccines, such as BCG, measles vaccination, and other whole-microorganism vaccines. In this review, we will present the mechanisms of trained immunity responsible for the long-lasting effects of vaccines on the innate immune system....

Bacillus Calmette-Guérin-Induced trained immunity is not protective for experimental influenza A/Anhui/1/2013 (H7N9) infection in mice

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de Bree, Charlotte L.C.J.; Marijnissen, Renoud J.; Kel, Junda M.

2018-01-01

potentially lead to an influenza pandemic, which may have severe consequences due to the absence of pre-existent immunity to this strain at population level. Currently there is no influenza A (H7N9) vaccine available. Therefore, in case of a pandemic outbreak, alternative preventive approaches are needed......, ideally even independent of the type of influenza virus outbreak. Bacillus Calmette-Guérin (BCG) is known to induce strong heterologous immunological effects, and it has been shown that BCG protects against non-related infection challenges in several mouse models. BCG immunization of mice as well as human......9) challenge. Here, we show that isolated splenocytes as well as peritoneal macrophages of BCG-immunized BALB/c mice displayed a trained immunity phenotype resulting in increased innate cytokine responses upon ex vivo restimulation. However, after H7N9 infection, no significant differences were...

Mucosal immune response in broilers following vaccination with inactivated influenza and recombinant Bacillus subtilis

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Mucosal and systemic immunity were observed in broilers vaccinated with mannosylated chitosan adjuvated (MCA) inactivated A/Turkey/Virginia/158512/2002 (H7N2) and administered with and without recombinant Bacillus subtilis to elicit heterologous influenza strain protection. Previously, mucosal immu...

A two-dose heterologous prime-boost vaccine regimen eliciting sustained immune responses to Ebola Zaire could support a preventive strategy for future outbreaks.

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Shukarev, Georgi; Callendret, Benoit; Luhn, Kerstin; Douoguih, Macaya

2017-02-01

The consequences of the 2013-16 Ebola Zaire virus disease epidemic in West Africa were grave. The economies, healthcare systems and communities of Guinea, Sierra Leone and Liberia were devastated by over 18 months of active Ebola virus transmission, followed by sporadic resurgences potentially related to sexual transmission by survivors with viral persistence in body fluids following recovery. The need to develop and implement strategies to prevent and mitigate future outbreaks is now beyond dispute. The potential for unpredictable outbreaks of indeterminate duration, and control challenges posed by the possibility of sporadic re-emergence, mean that implementation of an effective vaccination program for outbreak containment necessitates a vaccine providing durable immunity. Heterologous prime-boost vaccine regimens deliver the same or similar antigens through different vaccine types, the first to prime and the second to boost the immune system. Ad26.ZEBOV/MVA-BN-Filo is an investigational Ebola Zaire vaccine regimen that uses this heterologous prime-boost approach. Preliminary Phase 1 data suggest that Ad26.ZEBOV/MVA-BN-Filo confers durable immunity for at least 240 d and is well-tolerated with a good safety profile. This regimen may therefore be suitable for prophylactic use in a regional or targeted population vaccination strategy, and could potentially aid prevention and control of future Ebola outbreaks.

Babesia divergens: protection of intact calves against heterologous challenge by the injection of irradiated piroplasms

Energy Technology Data Exchange (ETDEWEB)

Lewis, D; Purnell, R E; Brocklesby, D W [Agricultural Research Council, Compton (UK). Inst. for Research on Animal Diseases

1980-03-01

Blood from a splenectomized calf infected with Babesia divergens was divided into 20 ml aliquots which were ..gamma..-irradiated at doses of 0, 24, 28, 32, 36 and 40 krad and then inoculated into groups of three intact calves. Animals receiving non-irradiated blood had typical mild B. divergens reactions, but those receiving irradiated blood had either very mild reactions or no overt reaction. When the calves were challenged with a similar number (7.5 X 10/sup 9/) of heterologous parasites of a recently-isolated field strain, those which had received blood irradiated at 0, 24, 28 and 32 krad were all immune whereas four of the five surviving animals which had received blood irradiated at 36 or 40 krad were susceptible. The immune status of individual cattle was reflected accurately in the results of the micro-ELISA test, which detected a significant rise in serum antibody titre of the four susceptible animals by day 21 after challenge.

Babesia divergens: protection of intact calves against heterologous challenge by the injection of irradiated piroplasms

International Nuclear Information System (INIS)

Lewis, D.; Purnell, R.E.; Brocklesby, D.W.

1980-01-01

Blood from a splenectomized calf infected with Babesia divergens was divided into 20 ml aliquots which were γ-irradiated at doses of 0, 24, 28, 32, 36 and 40 krad and then inoculated into groups of three intact calves. Animals receiving non-irradiated blood had typical mild B. divergens reactions, but those receiving irradiated blood had either very mild reactions or no overt reaction. When the calves were challenged with a similar number (7.5 X 10 9 ) of heterologous parasites of a recently-isolated field strain, those which had received blood irradiated at 0, 24, 28 and 32 krad were all immune whereas four of the five surviving animals which had received blood irradiated at 36 or 40 krad were susceptible. The immune status of individual cattle was reflected accurately in the results of the micro-ELISA test, which detected a significant rise in serum antibody titre of the four susceptible animals by day 21 after challenge. (Auth.)

Studies on the transfer of protective immunity with lymphoid cells from mice immune to malaria sporozoites

International Nuclear Information System (INIS)

Verhave, J.P.; Strickland, G.T.; Jaffe, H.A.; Ahmed, A.

1978-01-01

In an effort to understand the mechanisms involved in the protective immunity to malarial sporozoites, an A/J mouse/Plasmodium berghei model was studied. Protective immunity could consistently be adoptively transferred only by using sublethal irradiation of recipients (500 R); a spleen equivalent (100 x 10 6 ) of donor cells from immune syngeneic mice; and a small booster immunization (1 x 10 4 ) of recipients with irradiation-attenuated sporozoites. Recipient animals treated in this manner were protected from lethal challenge with 1 x 10 4 nonattenuated sporozoites. Immune and nonimmune serum and spleen cells from nonimmune animals did not protect recipient mice. Fewer immune spleen cells (50 x 10 6 ) protected some recipients. In vitro treatment of immune spleen cells with anti-theta sera and complement abolished their ability to transfer protection. This preliminary study suggests that protective sporozoite immunity can be transferred with cells, and that it is T cell dependent

Homologous and heterologous antibody responses of mice immunized with purified feline herpesvirus type 1 and canine herpesvirus glycoproteins.

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Limcumpao, J A; Horimoto, T; Xuan, X N; Tohya, Y; Azetaka, M; Takahashi, E; Mikami, T

1991-06-01

The three glycoproteins each of feline herpesvirus type 1 (FHV-1) and canine herpesvirus (CHV) were purified by affinity chromatography using glycoprotein-specific monoclonal antibodies and used individually or in combination in immunizing mice to determine their relative immunogenicity. All the glycoproteins induced detectable virus neutralizing antibodies to the homologous virus but FHV-1 gp143/108 and its cross-reacting counterpart, CHV gp145/112, elicited the highest titers not only to the homologous virus but to the heterologous virus as well. The production of ELISA antibodies after glycoprotein immunization was variable, while hemagglutination-inhibiting antibodies were produced by only 1 out of 10 FHV-1 gp60-inoculated mice. In general, the antibody titers induced by CHV glycoproteins were lower than those by FHV-1 glycoproteins. These results indicate that these glycoproteins may be useful as subunit vaccines against FHV-1 and CHV infections.

MVA-based H5N1 vaccine affords cross-clade protection in mice against influenza A/H5N1 viruses at low doses and after single immunization.

Directory of Open Access Journals (Sweden)

Joost H C M Kreijtz

Full Text Available Human infections with highly pathogenic avian influenza viruses of the H5N1 subtype, frequently reported since 2003, result in high morbidity and mortality. It is feared that these viruses become pandemic, therefore the development of safe and effective vaccines is desirable. MVA-based H5N1 vaccines already proved to be effective when two immunizations with high doses were used. Dose-sparing strategies would increase the number of people that can be vaccinated when the amount of vaccine preparations that can be produced is limited. Furthermore, protective immunity is induced ideally after a single immunization. Therefore the minimal requirements for induction of protective immunity with a MVA-based H5N1 vaccine were assessed in mice. To this end, mice were vaccinated once or twice with descending doses of a recombinant MVA expressing the HA gene of influenza virus A/Vietnam/1194/04. The protective efficacy was determined after challenge infection with the homologous clade 1 virus and a heterologous virus derived from clade 2.1, A/Indonesia/5/05 by assessing weight loss, virus replication and histopathological changes. It was concluded that MVA-based vaccines allowed significant dose-sparing and afford cross-clade protection, also after a single immunization, which are favorable properties for an H5N1 vaccine candidate.

A T-cell response to a liver-stage Plasmodium antigen is not boosted by repeated sporozoite immunizations

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Murphy, Sean C.; Kas, Arnold; Stone, Brad C.; Bevan, Michael J.

2013-01-01

Development of an antimalarial subunit vaccine inducing protective cytotoxic T lymphocyte (CTL)-mediated immunity could pave the way for malaria eradication. Experimental immunization with sporozoites induces this type of protective response, but the extremely large number of proteins expressed by Plasmodium parasites has so far prohibited the identification of sufficient discrete T-cell antigens to develop subunit vaccines that produce sterile immunity. Here, using mice singly immunized with Plasmodium yoelii sporozoites and high-throughput screening, we identified a unique CTL response against the parasite ribosomal L3 protein. Unlike CTL responses to the circumsporozoite protein (CSP), the population of L3-specific CTLs was not expanded by multiple sporozoite immunizations. CSP is abundant in the sporozoite itself, whereas L3 expression does not increase until the liver stage. The response induced by a single immunization with sporozoites reduces the parasite load in the liver so greatly during subsequent immunizations that L3-specific responses are only generated during the primary exposure. Functional L3-specific CTLs can, however, be expanded by heterologous prime-boost regimens. Thus, although repeat sporozoite immunization expands responses to preformed antigens like CSP that are present in the sporozoite itself, this immunization strategy may not expand CTLs targeting parasite proteins that are synthesized later. Heterologous strategies may be needed to increase CTL responses across the entire spectrum of Plasmodium liver-stage proteins. PMID:23530242

Differential protective effects of immune lymphoid cells against transplanted line Ib leukemia and immune polioencephalomyelitis

International Nuclear Information System (INIS)

Duffey, P.S.; Lukasewycz, O.A.; Olson, D.S.; Murphy, W.H.

1978-01-01

The capacity of immune cells obtained from the major lymphoid compartments to protect C58 mice from transplanted line Ib leukemia, and from an age-dependent autoimmune CNS disease (immune polioencephalomyelitis = IPE) elicited by immunizing old C58 mice with inactivated Ib cells was quantified. Cells used for comparative adoptive protection tests were harvested from the major lymphoid compartments 14 to 15 days after young C58 mice were immunized with inactivated Ib cell preparations. Regression curves were plotted from survival data and the log 10 PD 50 values were determined. Immune spleen (ISC) and peritoneal cells (IPEC) were significantly more protective against transplanted Ib cells than immune lymph node (ILNC), thymic (ITC), and marrow cells (IMC). In contrast, IPEC and IMC were not protective against IPE and ITC were only marginally protective. ILNC afforded significant protection to transplantable leukemia but were only marginally protective to IPE. When ISC were treated with anti-thy 1.2 serum and complement, protection against transplanted leukemia and IPE was reduced > 99%. When donors of immune lymphoid cells were treated with 12.5 mg of cortisone acetate daily for 2 days before lymphoid cells were harvested, protection against transplanted Ib cells by ISC was reduced by approximately 90% whereas protection against IPE was totally eliminated. Considered together, these results indicate that the protective mechanisms to transplantable leukemia and IPE differ significantly in the same indicator mouse strain

Friends and foes of tuberculosis: modulation of protective immunity.

Science.gov (United States)

Brighenti, Susanna; Joosten, Simone A

2018-05-27

Protective immunity in tuberculosis (TB) is subject of debate in the TB research community, as this is key to fully understand TB pathogenesis and to develop new promising tools for TB diagnosis and prognosis as well as a more efficient TB vaccine. IFN-γ producing CD4 + T cells are key in TB control, but may not be sufficient to provide protection. Additional subsets have been identified that contribute to protection such as multifunctional and cytolytic T cell subsets, including classical and non-classical T cells as well as novel innate immune cell subsets resulting from trained immunity. However, to define protective immune responses against TB, the complexity of balancing TB immunity also has to be considered. In this review, insights in effector cell immunity and how this is modulated by regulatory cells, associated comorbidities and the host microbiome is discussed. We systematically map how different suppressive immune cell subsets may affect effector cell responses at the local site of infection. We also dissect how common co-morbidities such as HIV, helminthes and diabetes may bias protective TB immunity towards pathogenic and regulatory responses. Finally, also the composition and diversity of the microbiome in the lung and gut could affect host TB immunity. Understanding these various aspects of the immunological balance in the human host is fundamental to prevent TB infection and disease. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Passive immunization with a polyclonal antiserum to the hemoglobin receptor of Haemophilus ducreyi confers protection against a homologous challenge in the experimental swine model of chancroid.

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Leduc, Isabelle; Fusco, William G; Choudhary, Neelima; Routh, Patty A; Cholon, Deborah M; Hobbs, Marcia M; Almond, Glen W; Orndorff, Paul E; Elkins, Christopher

2011-08-01

Haemophilus ducreyi, the etiologic agent of chancroid, has an obligate requirement for heme. Heme is acquired by H. ducreyi from its human host via TonB-dependent transporters expressed at its bacterial surface. Of 3 TonB-dependent transporters encoded in the genome of H. ducreyi, only the hemoglobin receptor, HgbA, is required to establish infection during the early stages of the experimental human model of chancroid. Active immunization with a native preparation of HgbA (nHgbA) confers complete protection in the experimental swine model of chancroid, using either Freund's or monophosphoryl lipid A as adjuvants. To determine if transfer of anti-nHgbA serum is sufficient to confer protection, a passive immunization experiment using pooled nHgbA antiserum was conducted in the experimental swine model of chancroid. Pigs receiving this pooled nHgbA antiserum were protected from a homologous, but not a heterologous, challenge. Passively transferred polyclonal antibodies elicited to nHgbA bound the surface of H. ducreyi and partially blocked hemoglobin binding by nHgbA, but were not bactericidal. Taken together, these data suggest that the humoral immune response to the HgbA vaccine is protective against an H. ducreyi infection, possibly by preventing acquisition of the essential nutrient heme.

Passive Immunization with a Polyclonal Antiserum to the Hemoglobin Receptor of Haemophilus ducreyi Confers Protection against a Homologous Challenge in the Experimental Swine Model of Chancroid▿

Science.gov (United States)

Leduc, Isabelle; Fusco, William G.; Choudhary, Neelima; Routh, Patty A.; Cholon, Deborah M.; Hobbs, Marcia M.; Almond, Glen W.; Orndorff, Paul E.; Elkins, Christopher

2011-01-01

Haemophilus ducreyi, the etiologic agent of chancroid, has an obligate requirement for heme. Heme is acquired by H. ducreyi from its human host via TonB-dependent transporters expressed at its bacterial surface. Of 3 TonB-dependent transporters encoded in the genome of H. ducreyi, only the hemoglobin receptor, HgbA, is required to establish infection during the early stages of the experimental human model of chancroid. Active immunization with a native preparation of HgbA (nHgbA) confers complete protection in the experimental swine model of chancroid, using either Freund's or monophosphoryl lipid A as adjuvants. To determine if transfer of anti-nHgbA serum is sufficient to confer protection, a passive immunization experiment using pooled nHgbA antiserum was conducted in the experimental swine model of chancroid. Pigs receiving this pooled nHgbA antiserum were protected from a homologous, but not a heterologous, challenge. Passively transferred polyclonal antibodies elicited to nHgbA bound the surface of H. ducreyi and partially blocked hemoglobin binding by nHgbA, but were not bactericidal. Taken together, these data suggest that the humoral immune response to the HgbA vaccine is protective against an H. ducreyi infection, possibly by preventing acquisition of the essential nutrient heme. PMID:21646451

Immune mechanisms in Babesia-infected animals

International Nuclear Information System (INIS)

Phillips, R.S.

1980-01-01

The course of a Babesia infection depends on the species of host and parasite involved. Animals infected with virulent babesias may need chemotherapy before acquired immunity develops. Maintenance of immunity is not dependent on the presence of the parasite. Babesia infections are characteristically of long duration. The immune response to babesias includes both humoral and cellular components. Antibody levels detected in serodiagnostic tests do not relate to levels of resistance to the parasite. Some antibodies, however, appear to be protective. Antiparasitic antibodies may damage parasites in or outside the red cell and act as opsonins. T-cell-deficient and anti-lymphocyte-serum-treated rodents are more susceptible to rodent piroplasms indicating a role for T-cells as either helper cells and/or as mediators of cell-mediated immunity (CMI). There is indirect evidence of CMI, but the cell-mediated mechanisms involved in parasite killing are not known. In domestic animals immunity is largely species- and strain-specific. Antigenic variation by babesias occurs. In rodents, however, there is cross-immunity between different species of rodent piroplasms and between rodent piroplasms and some malaria parasites. Prior infection with agents such as BCG, and Corynebacterium parvum, gives mice non-specific resistance to rodent piroplasms possibly mediated through a soluble non-antibody factor. This factor may also be liberated during piroplasm infections and by being toxic to malaria parasites account for heterologous immunity. Active immunization against babesias has been achieved with avirulent strains, irradiated parasites and dead parasites in adjuvant. During Babesia infections the primary and, to a lesser degree, the secondary immune response to heterologous antigens can be depressed. Maximum depression coincides with peak parasitaemia when antigen priming may be abolished completely. Immunosuppression during Babesia infections can prolong or exacerbate concurrent

In Vivo Differences in the Virulence, Pathogenicity, and Induced Protective Immunity of wboA Mutants from Genetically Different Parent Brucella spp.

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Wang, Zhen; Niu, Jianrui; Wang, Shuangshan

2013-01-01

To explore the effects of the genetic background on the characteristics of wboA gene deletion rough mutants generated from different parent Brucella sp. strains, we constructed the rough-mutant strains Brucella melitensis 16 M-MB6, B. abortus 2308-SB6, B. abortus S19-RB6, and B. melitensis NI-NB6 and evaluated their survival, pathogenicity, and induced protective immunity in mice and sheep. In mice, the survival times of the four mutants were very different in the virulence assay, from less than 6 weeks for B. abortus S19-RB6 to 11 weeks for B. abortus 2308-SB6 and B. melitensis NI-NB6. However, B. abortus S19-RB6 and B. melitensis 16 M-MB6, with a shorter survival time in mice, offered better protection against challenges with B. abortus 2308 in protection tests than B. abortus 2308-SB6 and B. melitensis NI-NB6. It seems that the induced protective immunity of each mutant might not be associated with its survival time in vivo. In the cross-protection assay, both B. melitensis 16 M-MB6 and B. abortus S19-RB6 induced greater protection against homologous challenges than heterologous challenges. When pregnant sheep were inoculated with B. abortus S19-RB6 and B. melitensis 16 M-MB6, B. abortus S19-RB6 did not induce abortion, whereas B. melitensis 16 M-MB6 did. These results demonstrated the differences in virulence, pathogenicity, and protective immunity in vivo in the wboA deletion mutants from genetically different parent Brucella spp. and also indicated that future rough vaccine strain development could be promising if suitable parent Brucella strains and/or genes were selected. PMID:23239800

A live attenuated cold-adapted influenza A H7N3 virus vaccine provides protection against homologous and heterologous H7 viruses in mice and ferrets

International Nuclear Information System (INIS)

Joseph, Tomy; McAuliffe, Josephine; Lu, Bin; Vogel, Leatrice; Swayne, David; Jin, Hong; Kemble, George; Subbarao, Kanta

2008-01-01

The appearance of human infections caused by avian influenza A H7 subtype viruses underscores their pandemic potential and the need to develop vaccines to protect humans from viruses of this subtype. A live attenuated H7N3 virus vaccine was generated by reverse genetics using the HA and NA genes of a low pathogenicity A/chicken/BC/CN-6/04 (H7N3) virus and the six internal protein genes of the cold-adapted A/Ann Arbor/6/60 ca (H2N2) virus. The reassortant H7N3 BC 04 ca vaccine virus was temperature sensitive and showed attenuation in mice and ferrets. Intranasal immunization with one dose of the vaccine protected mice and ferrets when challenged with homologous and heterologous H7 viruses. The reassortant H7N3 BC 04 ca vaccine virus showed comparable levels of attenuation, immunogenicity and efficacy in mice and ferret models. The safety, immunogenicity, and efficacy of this vaccine in mice and ferrets support the evaluation of this vaccine in clinical trials

Microneedle delivery of trivalent influenza vaccine to the skin induces long-term cross-protection.

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Kim, Yeu-Chun; Lee, Su-Hwa; Choi, Won-Hyung; Choi, Hyo-Jick; Goo, Tae-Won; Lee, Ju-Hie; Quan, Fu-Shi

2016-12-01

A painless self-immunization method with effective and broad cross-protection is urgently needed to prevent infections against newly emerging influenza viruses. In this study, we investigated the cross-protection efficacy of trivalent influenza vaccine containing inactivated A/PR/8/34 (H1N1), A/Hong Kong/68 (H3N2) and B/Lee/40 after skin vaccination using microneedle patches coated with this vaccine. Microneedle vaccination of mice in the skin provided 100% protection against lethal challenges with heterologous pandemic strain influenza A/California/04/09, heterogeneous A/Philippines/2/82 and B/Victoria/287 viruses 8 months after boost immunization. Cross-reactive serum IgG antibody responses against heterologous influenza viruses A/California/04/09, A/Philippines/2/82 and B/Victoria/287 were induced at high levels. Hemagglutination inhibition titers were also maintained at high levels against these heterogeneous viruses. Microneedle vaccination induced substantial levels of cross-reactive IgG antibody responses in the lung and cellular immune responses, as well as cross-reactive antibody-secreting plasma cells in the spleen. Viral loads in the lung were significantly (p skin vaccination with trivalent vaccine using a microneedle array could provide protection against seasonal epidemic or new pandemic strain of influenza viruses.

Vaccination with a HSV-2 UL24 mutant induces a protective immune response in murine and guinea pig vaginal infection models.

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Visalli, Robert J; Natuk, Robert J; Kowalski, Jacek; Guo, Min; Blakeney, Susan; Gangolli, Seema; Cooper, David

2014-03-10

The rational design and development of genetically attenuated HSV-2 mutant viruses represent an attractive approach for developing both prophylactic and therapeutic vaccines for genital herpes. Previously, HSV-2 UL24 was shown to be a virulence determinant in both murine and guinea pig vaginal infection models. An UL24-βgluc insertion mutant produced syncytial plaques and replicated to nearly wild type levels in tissue culture, but induced little or no pathological effects in recipient mice or guinea pigs following vaginal infection. Here we report that immunization of mice or guinea pigs with high or low doses of UL24-βgluc elicited a highly protective immune response. UL24-βgluc immunization via the vaginal or intramuscular routes was demonstrated to protect mice from a lethal vaginal challenge with wild type HSV-2. Moreover, antigen re-stimulated splenic lymphocytes harvested from immunized mice exhibited both HSV-2 specific CTL activity and IFN-γ expression. Humoral anti-HSV-2 responses in serum were Th1-polarized (IgG2a>IgG1) and contained high-titer anti-HSV-2 neutralizing activity. Guinea pigs vaccinated subcutaneously with UL24-βgluc or the more virulent parental strain (186) were challenged with a heterologous HSV-2 strain (MS). Acute disease scores were nearly indistinguishable in guinea pigs immunized with either virus. Recurrent disease scores were reduced in UL24-βgluc immunized animals but not to the same extent as those immunized with strain 186. In addition, challenge virus was not detected in 75% of guinea pigs subcutaneously immunized with UL24-βgluc. In conclusion, disruption of the UL24 gene is a prime target for the development of a genetically attenuated live HSV-2 vaccine. Copyright © 2014 Elsevier Ltd. All rights reserved.

Balancing immune protection and immune pathology by CD8+ T cell responses to influenza infection

Directory of Open Access Journals (Sweden)

Susu eDuan

2016-02-01

Full Text Available Influenza A virus (IAV is a significant human pathogen causing annual epidemics and periodic pandemics. CD8+ cytotoxic T lymphocyte (CTL-mediated immunity contributes to clearance of virus-infected cells; CTL immunity targeting the conserved internal proteins of IAVs is a key protection mechanism when neutralizing antibodies are absent during heterosubtypic IAV infection. However, CTL infiltration into the airways, their cytotoxicity, and the effects of produced pro-inflammatory cytokines can cause severe lung tissue injury, thereby contributing to immunopathology. Studies have discovered complicated and exquisite stimulatory and inhibitory mechanisms that regulate CTL magnitude and effector activities during IAV infection. Here, we review the state of knowledge on the roles of IAV-specific CTLs in immune protection and immunopathology during IAV infection in animal models, highlighting the key findings of various requirements and constraints regulating the balance of immune protection and pathology involved in CTL immunity. We also discuss the evidence of cross-reactive CTL immunity as a positive correlate of cross-subtype protection during secondary IAV infection in both animal and human studies. We argue that the effects of CTL immunity on protection and immunopathology depend on multiple layers of host and viral factors, including complex host mechanisms to regulate CTL magnitude and effector activity, the pathogenic nature of the IAV, the innate response milieu, and the host historical immune context of influenza infection. Future efforts are needed to further understand these key host and viral factors, especially to differentiate those that constrain optimally effective CTL anti-viral immunity from those necessary to restrain CTL-mediated nonspecific immunopathology in the various contexts of IAV infection, in order to develop better vaccination and therapeutic strategies for modifying protective CTL immunity.

Applying Convergent Immunity to Innovative Vaccines Targeting Staphylococcus aureus

Science.gov (United States)

Yeaman, Michael R.; Filler, Scott G.; Schmidt, Clint S.; Ibrahim, Ashraf S.; Edwards, John E.; Hennessey, John P.

2014-01-01

Recent perspectives forecast a new paradigm for future “third generation” vaccines based on commonalities found in diverse pathogens or convergent immune defenses to such pathogens. For Staphylococcus aureus, recurring infections and a limited success of vaccines containing S. aureus antigens imply that native antigens induce immune responses insufficient for optimal efficacy. These perspectives exemplify the need to apply novel vaccine strategies to high-priority pathogens. One such approach can be termed convergent immunity, where antigens from non-target organisms that contain epitope homologs found in the target organism are applied in vaccines. This approach aims to evoke atypical immune defenses via synergistic processes that (1) afford protective efficacy; (2) target an epitope from one organism that contributes to protective immunity against another; (3) cross-protect against multiple pathogens occupying a common anatomic or immunological niche; and/or (4) overcome immune subversion or avoidance strategies of target pathogens. Thus, convergent immunity has a potential to promote protective efficacy not usually elicited by native antigens from a target pathogen. Variations of this concept have been mainstays in the history of viral and bacterial vaccine development. A more far-reaching example is the pre-clinical evidence that specific fungal antigens can induce cross-kingdom protection against bacterial pathogens. This trans-kingdom protection has been demonstrated in pre-clinical studies of the recombinant Candida albicans agglutinin-like sequence 3 protein (rAls3) where it was shown that a vaccine containing rAls3 provides homologous protection against C. albicans, heterologous protection against several other Candida species, and convergent protection against several strains of S. aureus. Convergent immunity reflects an intriguing new approach to designing and developing vaccine antigens and is considered here in the context of vaccines to target S

Applying Convergent Immunity to Innovative Vaccines Targeting Staphylococcus aureus

Directory of Open Access Journals (Sweden)

Michael R Yeaman

2014-09-01

Full Text Available Recent perspectives forecast a new paradigm for future 3rd generation vaccines based on commonalities found in diverse pathogens or convergent immune defenses to such pathogens. For Staphylococcus aureus, recurring infections and a limited success of vaccines containing S. aureus antigens imply that native antigens induce immune responses insufficient for optimal efficacy. These perspectives exemplify the need to apply novel vaccine strategies to high priority pathogens. One such approach can be termed convergent immunity, where antigens from non-target organisms that contain epitope homologues found in the target organism are applied in vaccines. This approach aims to evoke atypical immune defenses via synergistic processes that 1 afford protective efficacy; 2 target an epitope from one organism that contributes to protective immunity against another; 3 cross-protect against multiple pathogens occupying a common anatomic or immunologic niche; and/or 4 overcome immune subversion or avoidance strategies of target pathogens. Thus, convergent immunity has a potential to promote protective efficacy not usually elicited by native antigens from a target pathogen. Variations of this concept have been mainstays in the history of viral and bacterial vaccine development. A more far-reaching example is the pre–clinical evidence that specific fungal antigens can induce cross-kingdom protection against bacterial pathogens. This trans-kingdom protection has been demonstrated in preclinical studies of the recombinant Candida albicans agglutinin-like sequence 3 protein (rAls3 where it was shown that a vaccine containing rAls3 provides homologous protection against C. albicans, heterologous protection against several other Candida species, and convergent protection against several strains of S. aureus. Convergent immunity reflects an intriguing new approach to designing and developing vaccine antigens and is considered here in the context of vaccines to target

Immunization with the Haemophilus ducreyi hemoglobin receptor HgbA protects against infection in the swine model of chancroid.

Science.gov (United States)

Afonina, Galyna; Leduc, Isabelle; Nepluev, Igor; Jeter, Chrystina; Routh, Patty; Almond, Glen; Orndorff, Paul E; Hobbs, Marcia; Elkins, Christopher

2006-04-01

The etiologic agent of chancroid is Haemophilus ducreyi. To fulfill its obligate requirement for heme, H. ducreyi uses two TonB-dependent receptors: the hemoglobin receptor (HgbA) and a receptor for free heme (TdhA). Expression of HgbA is necessary for H. ducreyi to survive and initiate disease in a human model of chancroid. In this study, we used a swine model of H. ducreyi infection to demonstrate that an experimental HgbA vaccine efficiently prevents chancroid, as determined by several parameters. Histological sections of immunized animals lacked typical microscopic features of chancroid. All inoculated sites from mock-immunized pigs yielded viable H. ducreyi cells, whereas no viable H. ducreyi cells were recovered from inoculated sites of HgbA-immunized pigs. Antibodies from sera of HgbA-immunized animals bound to and initiated antibody-dependent bactericidal activity against homologous H. ducreyi strain 35000HP and heterologous strain CIP542 ATCC; however, an isogenic hgbA mutant of 35000HP was not killed, proving specificity. Anti-HgbA immunoglobulin G blocked hemoglobin binding to the HgbA receptor, suggesting a novel mechanism of protection through the limitation of heme/iron acquisition by H. ducreyi. Such a vaccine strategy might be applied to other bacterial pathogens with strict heme/iron requirements. Taken together, these data suggest continuing the development of an HgbA subunit vaccine to prevent chancroid.

Microneedle-mediated immunization of an adenovirus-based malaria vaccine enhances antigen-specific antibody immunity and reduces anti-vector responses compared to the intradermal route.

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Carey, John B; Vrdoljak, Anto; O'Mahony, Conor; Hill, Adrian V S; Draper, Simon J; Moore, Anne C

2014-08-21

Substantial effort has been placed in developing efficacious recombinant attenuated adenovirus-based vaccines. However induction of immunity to the vector is a significant obstacle to its repeated use. Here we demonstrate that skin-based delivery of an adenovirus-based malaria vaccine, HAdV5-PyMSP1₄₂, to mice using silicon microneedles induces equivalent or enhanced antibody responses to the encoded antigen, however it results in decreased anti-vector responses, compared to intradermal delivery. Microneedle-mediated vaccine priming and resultant induction of low anti-vector antibody titres permitted repeated use of the same adenovirus vaccine vector. This resulted in significantly increased antigen-specific antibody responses in these mice compared to ID-treated mice. Boosting with a heterologous vaccine; MVA-PyMSP1₄₂ also resulted in significantly greater antibody responses in mice primed with HAdV5-PyMSP1₄₂ using MN compared to the ID route. The highest protection against blood-stage malaria challenge was observed when a heterologous route of immunization (MN/ID) was used. Therefore, microneedle-mediated immunization has potential to both overcome some of the logistic obstacles surrounding needle-and-syringe-based immunization as well as to facilitate the repeated use of the same adenovirus vaccine thereby potentially reducing manufacturing costs of multiple vaccines. This could have important benefits in the clinical ease of use of adenovirus-based immunization strategies.

Microneedle-mediated immunization of an adenovirus-based malaria vaccine enhances antigen-specific antibody immunity and reduces anti-vector responses compared to the intradermal route

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Carey, John B.; Vrdoljak, Anto; O'Mahony, Conor; Hill, Adrian V. S.; Draper, Simon J.; Moore, Anne C.

2014-01-01

Substantial effort has been placed in developing efficacious recombinant attenuated adenovirus-based vaccines. However induction of immunity to the vector is a significant obstacle to its repeated use. Here we demonstrate that skin-based delivery of an adenovirus-based malaria vaccine, HAdV5-PyMSP142, to mice using silicon microneedles induces equivalent or enhanced antibody responses to the encoded antigen, however it results in decreased anti-vector responses, compared to intradermal delivery. Microneedle-mediated vaccine priming and resultant induction of low anti-vector antibody titres permitted repeated use of the same adenovirus vaccine vector. This resulted in significantly increased antigen-specific antibody responses in these mice compared to ID-treated mice. Boosting with a heterologous vaccine; MVA-PyMSP142 also resulted in significantly greater antibody responses in mice primed with HAdV5-PyMSP142 using MN compared to the ID route. The highest protection against blood-stage malaria challenge was observed when a heterologous route of immunization (MN/ID) was used. Therefore, microneedle-mediated immunization has potential to both overcome some of the logistic obstacles surrounding needle-and-syringe-based immunization as well as to facilitate the repeated use of the same adenovirus vaccine thereby potentially reducing manufacturing costs of multiple vaccines. This could have important benefits in the clinical ease of use of adenovirus-based immunization strategies. PMID:25142082

[Virus strain specific serum neutralizing antibodies in children and adolescents immunized with a Russian mumps vaccine].

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Otrashevskaia, E V; Krasil'nikov, I V; Ignat'ev, G M

2010-01-01

Postvaccination immunity was studied in the children and teenagers without a history of clinical mumps infection, who had been immunized with the Leningrad-3 mumps vaccine. The level of specific lgG in ELISA and that and spectrum of their neutralizing activity against a vaccine strain and three heterologous mumps virus (MV) strains (genotypes A, C, and H) were measured. The investigation included 151 sera from the vaccinees aged 3 to 17 years, possessing the detectable specific IgG titers in ELISA and the detectable neutralizing titers against the vaccine strain. 97.4% of the vaccinees had neutralizing activity against 1-3 heterologous MV strains. A preponderance of neutralizing titers against heterologous MV strains by 1-log2 in some sera (6.5-32.5 depending on age) was most likely to suggest that the vaccinees' had been in contact with these virus strains in the past. In our investigation, a combination of positive IgG titers and neutralizing titers against the vaccine strain 2-log2 or higher provided the protection of the vaccinated children and teenagers against the symptomatic infection. There was a pronounced buster effect of the second immunization and a drop in the neutralizing activity of the sera from the vaccinated children and adolescents over time after the first and second immunization.

Characterization and Heterologous Expression of the Genes Encoding Enterocin A Production, Immunity, and Regulation in Enterococcus faecium DPC1146

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O’Keeffe, Triona; Hill, Colin; Ross, R. Paul

1999-01-01

Enterocin A is a small, heat-stable, antilisterial bacteriocin produced by Enterococcus faecium DPC1146. The sequence of a 10,879-bp chromosomal region containing at least 12 open reading frames (ORFs), 7 of which are predicted to play a role in enterocin biosynthesis, is presented. The genes entA, entI, and entF encode the enterocin A prepeptide, the putative immunity protein, and the induction factor prepeptide, respectively. The deduced proteins EntK and EntR resemble the histidine kinase and response regulator proteins of two-component signal transducing systems of the AgrC-AgrA type. The predicted proteins EntT and EntD are homologous to ABC (ATP-binding cassette) transporters and accessory factors, respectively, of several other bacteriocin systems and to proteins implicated in the signal-sequence-independent export of Escherichia coli hemolysin A. Immediately downstream of the entT and entD genes are two ORFs, the product of one of which, ORF4, is very similar to the product of the yteI gene of Bacillus subtilis and to E. coli protease IV, a signal peptide peptidase known to be involved in outer membrane lipoprotein export. Another potential bacteriocin is encoded in the opposite direction to the other genes in the enterocin cluster. This putative bacteriocin-like peptide is similar to LafX, one of the components of the lactacin F complex. A deletion which included one of two direct repeats upstream of the entA gene abolished enterocin A activity, immunity, and ability to induce bacteriocin production. Transposon insertion upstream of the entF gene also had the same effect, but this mutant could be complemented by exogenously supplied induction factor. The putative EntI peptide was shown to be involved in the immunity to enterocin A. Cloning of a 10.5-kb amplicon comprising all predicted ORFs and regulatory regions resulted in heterologous production of enterocin A and induction factor in Enterococcus faecalis, while a four-gene construct (entAITD) under the

Differential protective effects of immune lymphoid cells against transplanted line Ib leukemia and immune polioencephalomyelitis. [X radiation, mice

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Duffey, P.S.; Lukasewycz, O.A.; Olson, D.S.; Murphy, W.H.

1978-12-01

The capacity of immune cells obtained from the major lymphoid compartments to protect C58 mice from transplanted line Ib leukemia, and from an age-dependent autoimmune CNS disease (immune polioencephalomyelitis = IPE) elicited by immunizing old C58 mice with inactivated Ib cells was quantified. Cells used for comparative adoptive protection tests were harvested from the major lymphoid compartments 14 to 15 days after young C58 mice were immunized with inactivated Ib cell preparations. Regression curves were plotted from survival data and the log/sub 10/PD/sub 50/ values were determined. Immune spleen (ISC) and peritoneal cells (IPEC) were significantly more protective against transplanted Ib cells than immune lymph node (ILNC), thymic (ITC), and marrow cells (IMC). In contrast, IPEC and IMC were not protective against IPE and ITC were only marginally protective. ILNC afforded significant protection to transplantable leukemia but were only marginally protective to IPE. When ISC were treated with anti-thy 1.2 serum and complement, protection against transplanted leukemia and IPE was reduced > 99%. When donors of immune lymphoid cells were treated with 12.5 mg of cortisone acetate daily for 2 days before lymphoid cells were harvested, protection against transplanted Ib cells by ISC was reduced by approximately 90% whereas protection against IPE was totally eliminated. Considered together, these results indicate that the protective mechanisms to transplantable leukemia and IPE differ significantly in the same indicator mouse strain.

Recombinant lactic acid bacteria as delivery vectors of heterologous antigens: the future of vaccination?

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Trombert, A

2015-01-01

Lactic acid bacteria (LABs) are good candidates for the development of new oral vaccines and are attractive alternatives to attenuated pathogens. This review focuses on the use of wild-type and recombinant lactococci and lactobacilli with emphasis on their molecular design, immunomodulation and treatment of bacterial infections. The majority of studies related to recombinant LABs have focused on Lactococcus lactis, however, molecular tools have been successfully used for Lactobacillus spp. Recombinant lactobacilli and lactococci have several health benefits, such as immunomodulation, restoration of the microbiota, synthesis of antimicrobial substances and inhibition of virulence factors. In addition, protective immune responses that are well tolerated are induced by the expression of heterologous antigens from recombinant probiotics.

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

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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.

Overcoming tumor resistance by heterologous adeno-poxvirus combination therapy

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Markus Vähä-Koskela

2014-01-01

Full Text Available Successful cancer control relies on overcoming resistance to cell death and on activation of host antitumor immunity. Oncolytic viruses are particularly attractive in this regard, as they lyse infected tumor cells and trigger robust immune responses during the infection. However, repeated injections of the same virus promote antiviral rather than antitumor immunity and tumors may mount innate antiviral defenses to restrict oncolytic virus replication. In this article, we have explored if alternating the therapy virus could circumvent these problems. We demonstrate in two virus-resistant animal models a substantial delay in antiviral immune- and innate cellular response induction by alternating injections of two immunologically distinct oncolytic viruses, adenovirus, and vaccinia virus. Our results are in support of clinical development of heterologous adeno-/vaccinia virus therapy of cancer.

Bovine anaplasmosis with emphasis on immune responses and protection

International Nuclear Information System (INIS)

Ristic, M.

1980-01-01

Anaplasmosis is an infectious and transmissible disease manifested by progressive anaemia and the appearance of other characteristic disease symptoms. It is a world-wide tick-borne disease of cattle and some wild ruminants caused by the rickettsia Anaplasma marginale. By drawing on information obtained from studies of plasmodial cell cultures, a method has recently been developed for short-term in vitro cultivation of A. marginale. An attenuated Anaplasma organism capable of growth in both ovine and bovine erythrocytes was used to demonstrate that the in vitro system provided the necessary requirements for active transfer of the organism from cell to cell. Organismal antigens are found in the erythrocytes of infected animals, whereas soluble antigens are derived from their erythrocytes and serum. Serums from convalescing animals interact with these antigens in agglutination, complement fixation, fluorescent antibody and precipitation tests. Passive transfer of sera from immune to susceptible cattle, however, does not seem to confer protection against the infection and development of the disease. Studies that employed various tests for measuring cell-mediated immune (CMI) responses (leukocyte migration inhibition, blast transformation and cytotoxicity), in association with information collected simultaneously on antibody activity, have shown that both humoral and cellular immune responses are needed for the development of protective immunity in anaplasmosis. It was further shown that an active replication of Anaplasma is essential for induction of these two types of immune responses. Consequently, live virulent and attenuated immunogens fulfil requirements for induction of protective immunity. With the virulent agent, however, development of protective immunity is preceded by induction of auto-immune responses apparently associated with pathogenesis of anaemia in anaplasmosis. Inactivated immunogens derived from blood of infected cattle and used in combination with

Cellular immune responses to HPV-18, -31, and -53 in healthy volunteers immunized with recombinant HPV-16 L1 virus-like particles

International Nuclear Information System (INIS)

Pinto, Ligia A.; Viscidi, Raphael; Harro, Clayton D.; Kemp, Troy J.; Garcia-Pineres, Alfonso J.; Trivett, Matthew; Demuth, Franklin; Lowy, Douglas R.; Schiller, John T.; Berzofsky, Jay A.; Hildesheim, Allan

2006-01-01

Human papillomavirus-like particles (HPV VLP) are candidate vaccines that have shown to be efficacious in reducing infection and inducing robust antiviral immunity. Neutralizing antibodies generated by vaccination are largely type-specific, but little is known about the type-specificity of cellular immune responses to VLP vaccination. To determine whether vaccination with HPV-16 L1VLP induces cellular immunity to heterologous HPV types (HPV-18, HPV-31, and HPV-53), we examined proliferative and cytokine responses in vaccine (n = 11) and placebo (n = 5) recipients. Increased proliferative and cytokine responses to heterologous types were observed postvaccination in some individuals. The proportion of women responding to heterologous types postvaccination (36%-55%) was lower than that observed in response to HPV-16 (73%). Response to HPV-16 VLP predicted response to other types. The strongest correlations in response were observed between HPV-16 and HPV-31, consistent with their phylogenetic relatedness. In summary, PBMC from HPV-16 VLP vaccine recipients can respond to L1VLP from heterologous HPV types, suggesting the presence of conserved T cell epitopes

Pertussis Maternal Immunization: Narrowing the Knowledge Gaps on the Duration of Transferred Protective Immunity and on Vaccination Frequency

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Gaillard, María Emilia; Bottero, Daniela; Zurita, María Eugenia; Carriquiriborde, Francisco; Martin Aispuro, Pablo; Bartel, Erika; Sabater-Martínez, David; Bravo, María Sol; Castuma, Celina; Hozbor, Daniela Flavia

2017-01-01

Maternal safety through pertussis vaccination and subsequent maternal–fetal-antibody transfer are well documented, but information on infant protection from pertussis by such antibodies and by subsequent vaccinations is scarce. Since mice are used extensively for maternal-vaccination studies, we adopted that model to narrow those gaps in our understanding of maternal pertussis immunization. Accordingly, we vaccinated female mice with commercial acellular pertussis (aP) vaccine and measured offspring protection against Bordetella pertussis challenge and specific-antibody levels with or without revaccination. Maternal immunization protected the offspring against pertussis, with that immune protection transferred to the offspring lasting for several weeks, as evidenced by a reduction (4–5 logs, p protection to offspring up to the fourth pregnancy. Under the conditions of our experimental protocol, protection to offspring from the aP-induced immunity is transferred both transplacentally and through breastfeeding. Adoptive-transfer experiments demonstrated that transferred antibodies were more responsible for the protection detected in offspring than transferred whole spleen cells. In contrast to reported findings, the protection transferred was not lost after the vaccination of infant mice with the same or other vaccine preparations, and conversely, the immunity transferred from mothers did not interfere with the protection conferred by infant vaccination with the same or different vaccines. These results indicated that aP-vaccine immunization of pregnant female mice conferred protective immunity that is transferred both transplacentally and via offspring breastfeeding without compromising the protection boostered by subsequent infant vaccination. These results—though admittedly not necessarily immediately extrapolatable to humans—nevertheless enabled us to test hypotheses under controlled conditions through detailed sampling and data collection. These

Pertussis Maternal Immunization: Narrowing the Knowledge Gaps on the Duration of Transferred Protective Immunity and on Vaccination Frequency

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María Emilia Gaillard

2017-09-01

Full Text Available Maternal safety through pertussis vaccination and subsequent maternal–fetal-antibody transfer are well documented, but information on infant protection from pertussis by such antibodies and by subsequent vaccinations is scarce. Since mice are used extensively for maternal-vaccination studies, we adopted that model to narrow those gaps in our understanding of maternal pertussis immunization. Accordingly, we vaccinated female mice with commercial acellular pertussis (aP vaccine and measured offspring protection against Bordetella pertussis challenge and specific-antibody levels with or without revaccination. Maternal immunization protected the offspring against pertussis, with that immune protection transferred to the offspring lasting for several weeks, as evidenced by a reduction (4–5 logs, p < 0.001 in the colony-forming-units recovered from the lungs of 16-week-old offspring. Moreover, maternal-vaccination-acquired immunity from the first pregnancy still conferred protection to offspring up to the fourth pregnancy. Under the conditions of our experimental protocol, protection to offspring from the aP-induced immunity is transferred both transplacentally and through breastfeeding. Adoptive-transfer experiments demonstrated that transferred antibodies were more responsible for the protection detected in offspring than transferred whole spleen cells. In contrast to reported findings, the protection transferred was not lost after the vaccination of infant mice with the same or other vaccine preparations, and conversely, the immunity transferred from mothers did not interfere with the protection conferred by infant vaccination with the same or different vaccines. These results indicated that aP-vaccine immunization of pregnant female mice conferred protective immunity that is transferred both transplacentally and via offspring breastfeeding without compromising the protection boostered by subsequent infant vaccination. These results�

B cells are not essential for Lactobacillus-mediated protection against lethal pneumovirus infection*

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Percopo, Caroline M.; Dyer, Kimberly D.; Garcia-Crespo, Katia E.; Gabryszewski, Stanislaw J.; Shaffer, Arthur L.; Domachowske, Joseph B.; Rosenberg, Helene F.

2014-01-01

We have shown previously that priming of respiratory mucosa with live Lactobacillus species promotes robust and prolonged survival from an otherwise lethal infection with pneumonia virus of mice (PVM), a property known as heterologous immunity. Lactobacillus-priming results in a moderate reduction in virus recovery and a dramatic reduction in virus-induced proinflammatory cytokine production; the precise mechanisms underlying these findings remain to be elucidated. As B cells have been shown to promote heterologous immunity against respiratory virus pathogens under similar conditions, here we explore the role of B cells in Lactobacillus-mediated protection against acute pneumovirus infection. We found that Lactobacillus-primed mice feature elevated levels of airway immunoglobulins IgG, IgA and IgM and lung tissues with dense, B cell (B220+) enriched peribronchial and perivascular infiltrates with germinal centers consistent with descriptions of bronchus-associated lymphoid tissue. No B cells were detected in lung tissue of Lactobacillus-primed B-cell deficient μMT mice or Jh mice, and Lactobacillus-primed μMT mice had no characteristic infiltrates or airway immunoglobulins. Nonetheless, we observed diminished virus recovery and profound suppression of virus-induced proinflammatory cytokines CCL2, IFN-gamma, and CXCL10 in both wild-type and Lactobacillus-primed μMT mice. Furthermore, L. plantarum-primed, B-cell deficient μMT and Jh mice were fully protected from an otherwise lethal PVM infection, as were their respective wild-types. We conclude that B cells are dispensable for Lactobacillus-mediated heterologous immunity and were not crucial for promoting survival in response to an otherwise lethal pneumovirus infection. PMID:24748495

B cells are not essential for Lactobacillus-mediated protection against lethal pneumovirus infection.

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Percopo, Caroline M; Dyer, Kimberly D; Garcia-Crespo, Katia E; Gabryszewski, Stanislaw J; Shaffer, Arthur L; Domachowske, Joseph B; Rosenberg, Helene F

2014-06-01

We have shown previously that priming of respiratory mucosa with live Lactobacillus species promotes robust and prolonged survival from an otherwise lethal infection with pneumonia virus of mice, a property known as heterologous immunity. Lactobacillus priming results in a moderate reduction in virus recovery and a dramatic reduction in virus-induced proinflammatory cytokine production; the precise mechanisms underlying these findings remain to be elucidated. Because B cells have been shown to promote heterologous immunity against respiratory virus pathogens under similar conditions, in this study we explore the role of B cells in Lactobacillus-mediated protection against acute pneumovirus infection. We found that Lactobacillus-primed mice feature elevated levels of airway Igs IgG, IgA, and IgM and lung tissues with dense, B cell (B220(+))-enriched peribronchial and perivascular infiltrates with germinal centers consistent with descriptions of BALT. No B cells were detected in lung tissue of Lactobacillus-primed B cell deficient μMT mice or Jh mice, and Lactobacillus-primed μMT mice had no characteristic infiltrates or airway Igs. Nonetheless, we observed diminished virus recovery and profound suppression of virus-induced proinflammatory cytokines CCL2, IFN-γ, and CXCL10 in both wild-type and Lactobacillus-primed μMT mice. Furthermore, Lactobacillus plantarum-primed, B cell-deficient μMT and Jh mice were fully protected from an otherwise lethal pneumonia virus of mice infection, as were their respective wild-types. We conclude that B cells are dispensable for Lactobacillus-mediated heterologous immunity and were not crucial for promoting survival in response to an otherwise lethal pneumovirus infection.

Vaccination using recombinants influenza and adenoviruses encoding amastigote surface protein-2 are highly effective on protection against Trypanosoma cruzi infection.

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Barbosa, Rafael Polidoro Alves; Filho, Bruno Galvão; Dos Santos, Luara Isabela; Junior, Policarpo Ademar Sales; Marques, Pedro Elias; Pereira, Rafaela Vaz Sousa; Cara, Denise Carmona; Bruña-Romero, Oscar; Rodrigues, Maurício Martins; Gazzinelli, Ricardo Tostes; Machado, Alexandre Vieira

2013-01-01

In the present study we evaluated the protection raised by immunization with recombinant influenza viruses carrying sequences coding for polypeptides corresponding to medial and carboxi-terminal moieties of Trypanosoma cruzi ´s amastigote surface protein 2 (ASP2). Those viruses were used in sequential immunization with recombinant adenovirus (heterologous prime-boost immunization protocol) encoding the complete sequence of ASP2 (Ad-ASP2) in two mouse strains (C57BL/6 and C3H/He). The CD8 effector response elicited by this protocol was comparable to that observed in mice immunized twice with Ad-ASP2 and more robust than that observed in mice that were immunized once with Ad-ASP2. Whereas a single immunization with Ad-ASP2 sufficed to completely protect C57BL/6 mice, a higher survival rate was observed in C3H/He mice that were primed with recombinant influenza virus and boosted with Ad-ASP2 after being challenged with T. cruzi. Analyzing the phenotype of CD8+ T cells obtained from spleen of vaccinated C3H/He mice we observed that heterologous prime-boost immunization protocol elicited more CD8+ T cells specific for the immunodominant epitope as well as a higher number of CD8+ T cells producing TNF-α and IFN-γ and a higher mobilization of surface marker CD107a. Taken together, our results suggest that immunodominant subpopulations of CD8+ T elicited after immunization could be directly related to degree of protection achieved by different immunization protocols using different viral vectors. Overall, these results demonstrated the usefulness of recombinant influenza viruses in immunization protocols against Chagas Disease.

Immune Protection against Lethal Fungal-Bacterial Intra-Abdominal Infections.

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Lilly, Elizabeth A; Ikeh, Melanie; Nash, Evelyn E; Fidel, Paul L; Noverr, Mairi C

2018-01-16

Polymicrobial intra-abdominal infections (IAIs) are clinically prevalent and cause significant morbidity and mortality, especially those involving fungi. Our laboratory developed a mouse model of IAI and demonstrated that intraperitoneal inoculation with Candida albicans or other virulent non- albicans Candida (NAC) species plus Staphylococcus aureus resulted in 70 to 80% mortality in 48 to 72 h due to robust local and systemic inflammation (sepsis). Surprisingly, inoculation with Candida dubliniensis or Candida glabrata with S. aureus resulted in minimal mortality, and rechallenge of these mice with lethal C. albicans / S. aureus (i.e., coninfection) resulted in >90% protection. The purpose of this study was to define requirements for C. dubliniensis / S. aureus -mediated protection and interrogate the mechanism of the protective response. Protection was conferred by C. dubliniensis alone or by killed C. dubliniensis plus live S. aureus S. aureus alone was not protective, and killed S. aureus compromised C. dubliniensis -induced protection. C. dubliniensis / S. aureus also protected against lethal challenge by NAC plus S. aureus and could protect for a long-term duration (60 days between primary challenge and C. albicans/S. aureus rechallenge). Unexpectedly, mice deficient in T and B cells (Rag-1 knockouts [KO]) survived both the initial C. dubliniensis/S. aureus challenge and the C. albicans/S. aureus rechallenge, indicating that adaptive immunity did not play a role. Similarly, mice depleted of macrophages prior to rechallenge were also protected. In contrast, protection was associated with high numbers of Gr-1 hi polymorphonuclear leukocytes (PMNLs) in peritoneal lavage fluid within 4 h of rechallenge, and in vivo depletion of Gr-1 + cells prior to rechallenge abrogated protection. These results suggest that Candida species can induce protection against a lethal C. albicans / S. aureus IAI that is mediated by PMNLs and postulated to be a unique form of

Heterologous prime-boost vaccinations for poverty-related diseases: advantages and future prospects.

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Radosević, Katarina; Rodriguez, Ariane; Lemckert, Angelique; Goudsmit, Jaap

2009-05-01

Classical vaccination approaches, based on a single vaccine administered in a homologous prime-boost schedule and optimized to induce primarily neutralizing antibodies, are unlikely to be sufficiently efficacious to prevent TB, malaria or HIV infections. Novel vaccines, capable of inducing a more powerful immune response, in particular T-cell immunity, are desperately needed. Combining different vaccine modalities that are able to complement each other and induce broad and sustainable immunity is a promising approach. This review provides an overview of heterologous prime-boost vaccination modalities currently in development for the 'big three' poverty-related diseases and emphasizes the need for innovative vaccination approaches.

Cytomegalovirus in the Neonate: Immune Correlates of Infection and Protection

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Mark R. Schleiss

2013-01-01

Full Text Available Fetal and neonatal infections caused by human cytomegalovirus (CMV are important causes of morbidity and occasional mortality. Development of a vaccine against congenital CMV infection is a major public health priority. Vaccine design is currently focused on strategies that aim to elicit neutralizing antibody and T-cell responses, toward the goal of preventing primary or recurrent infection in women of child-bearing age. However, there has been relatively little attention given to understanding the mechanisms of immune protection against acquisition of CMV infection in the fetus and newborn and how this information might be exploited for vaccine design. There has similarly been an insufficient study of what deficits in the immune response to CMV, both for mother and fetus, may increase susceptibility to congenital infection and disease. Protection of the fetus against vertical transmission can likely be achieved by protection of the placenta, which has its own unique immunological milieu, further complicating the analysis of the correlates of protective immunity. In this review, the current state of knowledge about immune effectors of protection against CMV in the maternal, placental, and fetal compartments is reviewed. A better understanding of immune responses that prevent and/or predispose to infection will help in the development of novel vaccine strategies.

Cytomegalovirus in the Neonate: Immune Correlates of Infection and Protection

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Schleiss, Mark R.

2013-01-01

Fetal and neonatal infections caused by human cytomegalovirus (CMV) are important causes of morbidity and occasional mortality. Development of a vaccine against congenital CMV infection is a major public health priority. Vaccine design is currently focused on strategies that aim to elicit neutralizing antibody and T-cell responses, toward the goal of preventing primary or recurrent infection in women of child-bearing age. However, there has been relatively little attention given to understanding the mechanisms of immune protection against acquisition of CMV infection in the fetus and newborn and how this information might be exploited for vaccine design. There has similarly been an insufficient study of what deficits in the immune response to CMV, both for mother and fetus, may increase susceptibility to congenital infection and disease. Protection of the fetus against vertical transmission can likely be achieved by protection of the placenta, which has its own unique immunological milieu, further complicating the analysis of the correlates of protective immunity. In this review, the current state of knowledge about immune effectors of protection against CMV in the maternal, placental, and fetal compartments is reviewed. A better understanding of immune responses that prevent and/or predispose to infection will help in the development of novel vaccine strategies. PMID:24023565

Establishing a small animal model for evaluating protective immunity against mumps virus.

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Adrian Pickar

Full Text Available Although mumps vaccines have been used for several decades, protective immune correlates have not been defined. Recently, mumps outbreaks have occurred in vaccinated populations. To better understand the causes of the outbreaks and to develop means to control outbreaks in mumps vaccine immunized populations, defining protective immune correlates will be critical. Unfortunately, no small animal model for assessing mumps immunity exists. In this study, we evaluated use of type I interferon (IFN alpha/beta receptor knockout mice (IFN-α/βR-/- for such a model. We found these mice to be susceptible to mumps virus administered intranasally and intracranially. Passive transfer of purified IgG from immunized mice protected naïve mice from mumps virus infection, confirming the role of antibody in protection and demonstrating the potential for this model to evaluate mumps immunity.

Effectiveness analyses may underestimate protection of infants after group C meningococcal immunization.

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Vu, David M; Kelly, Dominic; Heath, Paul T; McCarthy, Noel D; Pollard, Andrew J; Granoff, Dan M

2006-07-15

Group C meningococcal conjugate-vaccine effectiveness in the United Kingdom declines from ~90% in the first year to 0% between 1 and 4 years after immunization in infants immunized at 2, 3, and 4 months of age and to 61% in toddlers given a single dose. Confidence intervals are wide, and the extent of protection is uncertain. Serum samples were obtained from children 3-5 years of age who were participants in a preschool booster-vaccine trial. Serum bactericidal activity was measured with human complement. Group C anticapsular antibody concentrations were measured by a radioantigen binding assay. Passive protection was analyzed in an infant rat bacteremia model. Serum samples from UK children who had been immunized 2-3 years earlier as infants or toddlers had higher levels of radioantigen binding, bactericidal activity, and passive protection than did historical control serum samples from unimmunized children (P or =1 : 4 (considered to be protective) than those immunized as toddlers (61% vs. 24%; Pprotection (50% and 41%, respectively; P=.4). We found no evidence of lower immunity in children immunized as infants than as toddlers. On the basis of serum bactericidal activity and/or passive protection, 40%-50% of both age groups are protected at 2-3 years after immunization, which was significantly greater than in unimmunized historical controls (<5%).

Heterologous Prime-Boost Vaccination Using an AS03B-Adjuvanted Influenza A(H5N1) Vaccine in Infants and Children <3 Years of Age

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Nolan, Terry; Izurieta, Patricia; Lee, Bee-Wah; Chan, Poh Chong; Marshall, Helen; Booy, Robert; Drame, Mamadou; Vaughn, David W.

2014-01-01

Background. Protecting young children from pandemic influenza should also reduce transmission to susceptible adults, including pregnant women. Methods. An open study assessed immunogenicity and reactogenicity of a heterologous booster dose of A/turkey/Turkey/1/2005(H5N1)-AS03B (AS03B is an Adjuvant System containing α-tocopherol and squalene in an oil-in-water emulsion [5.93 mg tocopherol]) in infants and children aged 6 to < 36 months that was given 6 months following 2-dose primary vaccination with A/Indonesia/05/2005(H5N1)-AS03B. Vaccines contained 1.9 µg of hemagglutinin antigen and AS03B. Hemagglutinin inhibition (HI) responses, microneutralization titers, and antineuraminidase antibody levels were assessed for 6 months following the booster vaccination. Results. For each age stratum (defined on the basis of the subject's age at first vaccination as 6 to < 12 months, 12 to < 24 months, and 24 to < 36 months) and overall (n = 113), European influenza vaccine licensure criteria were fulfilled for responses to A/turkey/Turkey/1/2005(H5N1) 10 days following the booster vaccination. Local pain and fever increased with consecutive doses. Anamnestic immune responses were demonstrated for HI, neutralizing, and antineuraminidase antibodies against vaccine-homologous/heterologous strains. Antibody responses to vaccine-homologous/heterologous strains persisted in all children 6 months following the booster vaccination. Conclusions. Prevaccination of young children with a clade 2 strain influenza A(H5N1) AS03-adjuvanted vaccine followed by heterologous booster vaccination boosted immune responses to the homologous strain and a related clade, with persistence for at least 6 months. The results support a prime-boost vaccination approach in young children for pandemic influenza preparedness. Clinical Trials Registration. NCT01323946. PMID:24973461

Trachoma: protective and pathogenic ocular immune responses to Chlamydia trachomatis.

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Victor H Hu

Full Text Available Trachoma, caused by Chlamydia trachomatis (Ct, is the leading infectious blinding disease worldwide. Chronic conjunctival inflammation develops in childhood and leads to eyelid scarring and blindness in adulthood. The immune response to Ct provides only partial protection against re-infection, which can be frequent. Moreover, the immune response is central to the development of scarring pathology, leading to loss of vision. Here we review the current literature on both protective and pathological immune responses in trachoma. The resolution of Ct infection in animal models is IFNγ-dependent, involving Th1 cells, but whether this is the case in human ocular infection still needs to be confirmed. An increasing number of studies indicate that innate immune responses arising from the epithelium and other innate immune cells, along with changes in matrix metalloproteinase activity, are important in the development of tissue damage and scarring. Current trachoma control measures, which are centred on repeated mass antibiotic treatment of populations, are logistically challenging and have the potential to drive antimicrobial resistance. A trachoma vaccine would offer significant advantages. However, limited understanding of the mechanisms of both protective immunity and immunopathology to Ct remain barriers to vaccine development.

A single dose of a DNA vaccine encoding apa coencapsulated with 6,6'-trehalose dimycolate in microspheres confers long-term protection against tuberculosis in Mycobacterium bovis BCG-primed mice.

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Carlétti, Dyego; Morais da Fonseca, Denise; Gembre, Ana Flávia; Masson, Ana Paula; Weijenborg Campos, Lívia; Leite, Luciana C C; Rodrigues Pires, Andréa; Lannes-Vieira, Joseli; Lopes Silva, Célio; Bonato, Vânia Luiza Deperon; Horn, Cynthia

2013-08-01

Mycobacterium bovis BCG prime DNA (Mycobacterium tuberculosis genes)-booster vaccinations have been shown to induce greater protection against tuberculosis (TB) than BCG alone. This heterologous prime-boost strategy is perhaps the most realistic vaccination for the future of TB infection control, especially in countries where TB is endemic. Moreover, a prime-boost regimen using biodegradable microspheres seems to be a promising immunization to stimulate a long-lasting immune response. The alanine proline antigen (Apa) is a highly immunogenic glycoprotein secreted by M. tuberculosis. This study investigated the immune protection of Apa DNA vaccine against intratracheal M. tuberculosis challenge in mice on the basis of a heterologous prime-boost regimen. BALB/c mice were subcutaneously primed with BCG and intramuscularly boosted with a single dose of plasmid carrying apa and 6,6'-trehalose dimycolate (TDM) adjuvant, coencapsulated in microspheres (BCG-APA), and were evaluated 30 and 70 days after challenge. This prime-boost strategy (BCG-APA) resulted in a significant reduction in the bacterial load in the lungs, thus leading to better preservation of the lung parenchyma, 70 days postinfection compared to BCG vaccinated mice. The profound effect of this heterologous prime-boost regimen in the experimental model supports its development as a feasible strategy for prevention of TB.

Heterologous Prime-Boost HIV-1 Vaccination Regimens in Pre-Clinical and Clinical Trials

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Julia L. Hurwitz

2010-02-01

Full Text Available Currently, there are more than 30 million people infected with HIV-1 and thousands more are infected each day. Vaccination is the single most effective mechanism for prevention of viral disease, and after more than 25 years of research, one vaccine has shown somewhat encouraging results in an advanced clinical efficacy trial. A modified intent-to-treat analysis of trial results showed that infection was approximately 30% lower in the vaccine group compared to the placebo group. The vaccine was administered using a heterologous prime-boost regimen in which both target antigens and delivery vehicles were changed during the course of inoculations. Here we examine the complexity of heterologous prime-boost immunizations. We show that the use of different delivery vehicles in prime and boost inoculations can help to avert the inhibitory effects caused by vector-specific immune responses. We also show that the introduction of new antigens into boost inoculations can be advantageous, demonstrating that the effect of ‘original antigenic sin’ is not absolute. Pre-clinical and clinical studies are reviewed, including our own work with a three-vector vaccination regimen using recombinant DNA, virus (Sendai virus or vaccinia virus and protein. Promising preliminary results suggest that the heterologous prime-boost strategy may possibly provide a foundation for the future prevention of HIV-1 infections in humans.

Long-term in vitro and in vivo effects of γ-irradiated BCG on innate and adaptive immunity

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Arts, Rob J W; Blok, Bastiaan A; Aaby, Peter

2015-01-01

were less strong than those induced by live BCG. γBCG vaccination in volunteers had only minimal effects on innate immunity, whereas a significant increase in heterologous Th1/Th17 immunity was observed. Our results indicate that γBCG induces long-term training of innate immunity in vitro. In vivo, γ......BCG vaccination is associated with a reduced mortality from nonmycobacterial infections. This is likely to be mediated by a combination of innate-immune memory ("trained immunity") and heterologous effects on adaptive immunity. As such, BCG could be used to boost host immunity...

Immunogenicity and protective efficacy of a live attenuated H5N1 vaccine in nonhuman primates.

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Shufang Fan

2009-05-01

Full Text Available The continued spread of highly pathogenic H5N1 influenza viruses among poultry and wild birds, together with the emergence of drug-resistant variants and the possibility of human-to-human transmission, has spurred attempts to develop an effective vaccine. Inactivated subvirion or whole-virion H5N1 vaccines have shown promising immunogenicity in clinical trials, but their ability to elicit protective immunity in unprimed human populations remains unknown. A cold-adapted, live attenuated vaccine with the hemagglutinin (HA and neuraminidase (NA genes of an H5N1 virus A/VN/1203/2004 (clade 1 was protective against the pulmonary replication of homologous and heterologous wild-type H5N1 viruses in mice and ferrets. In this study, we used reverse genetics to produce a cold-adapted, live attenuated H5N1 vaccine (AH/AAca that contains HA and NA genes from a recent H5N1 isolate, A/Anhui/2/05 virus (AH/05 (clade 2.3, and the backbone of the cold-adapted influenza H2N2 A/AnnArbor/6/60 virus (AAca. AH/AAca was attenuated in chickens, mice, and monkeys, and it induced robust neutralizing antibody responses as well as HA-specific CD4+ T cell immune responses in rhesus macaques immunized twice intranasally. Importantly, the vaccinated macaques were fully protected from challenge with either the homologous AH/05 virus or a heterologous H5N1 virus, A/bar-headed goose/Qinghai/3/05 (BHG/05; clade 2.2. These results demonstrate for the first time that a cold-adapted H5N1 vaccine can elicit protective immunity against highly pathogenic H5N1 virus infection in a nonhuman primate model and provide a compelling argument for further testing of double immunization with live attenuated H5N1 vaccines in human trials.

Multigenic DNA vaccine induces protective cross-reactive T cell responses against heterologous influenza virus in nonhuman primates.

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Merika T Koday

Full Text Available Recent avian and swine-origin influenza virus outbreaks illustrate the ongoing threat of influenza pandemics. We investigated immunogenicity and protective efficacy of a multi-antigen (MA universal influenza DNA vaccine consisting of HA, M2, and NP antigens in cynomolgus macaques. Following challenge with a heterologous pandemic H1N1 strain, vaccinated animals exhibited significantly lower viral loads and more rapid viral clearance when compared to unvaccinated controls. The MA DNA vaccine induced robust serum and mucosal antibody responses but these high antibody titers were not broadly neutralizing. In contrast, the vaccine induced broadly-reactive NP specific T cell responses that cross-reacted with the challenge virus and inversely correlated with lower viral loads and inflammation. These results demonstrate that a MA DNA vaccine that induces strong cross-reactive T cell responses can, independent of neutralizing antibody, mediate significant cross-protection in a nonhuman primate model and further supports development as an effective approach to induce broad protection against circulating and emerging influenza strains.

Discovering naturally processed antigenic determinants that confer protective T cell immunity

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

2013-01-01

and elicited protective TCD8 immunity against lethal intranasal VACV infection. Notably, efficient processing and stable presentation of immune determinants as well as the availability of naive TCD8 precursors were sufficient to drive a multifunctional, protective TCD8 response. Our approach uses fundamental...

Studies on pathogenesis and treatment of experimental immune complex glomerulonephrtis.

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Fleuren, Gerard Johannes Maria

1976-01-01

Chapter 1. In this thesis an investigation into pathogenetic mechanisms of epimembranous immune complex depostion in the glomeruli was described. For this study we used two related models of experimental immune complex glemerulonephritis: the heterologous and the autologous immune complex

Circumsporozoite Protein-Specific Kd-Restricted CD8+ T Cells Mediate Protective Antimalaria Immunity in Sporozoite-Immunized MHC-I-Kd Transgenic Mice

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Jing Huang

2014-01-01

Full Text Available Although the roles of CD8+ T cells and a major preerythrocytic antigen, the circumsporozoite (CS protein, in contributing protective antimalaria immunity induced by radiation-attenuated sporozoites, have been shown by a number of studies, the extent to which these players contribute to antimalaria immunity is still unknown. To address this question, we have generated C57BL/6 (B6 transgenic (Tg mice, expressing Kd molecules under the MHC-I promoter, called MHC-I-Kd-Tg mice. In this study, we first determined that a single immunizing dose of IrPySpz induced a significant level of antimalaria protective immunity in MHC-I-Kd-Tg mice but not in B6 mice. Then, by depleting various T-cell subsets in vivo, we determined that CD8+ T cells are the main mediator of the protective immunity induced by IrPySpz. Furthermore, when we immunized (MHC-I-Kd-Tg × CS-Tg F1 mice with IrPySpz after crossing MHC-I-Kd-Tg mice with PyCS-transgenic mice (CS-Tg, which are unable to mount PyCS-specific immunity, we found that IrPySpz immunization failed to induce protective antimalaria immunity in (MHC-I-Kd-Tg × CS-Tg F1 mice, thus indicating the absence of PyCS antigen-dependent immunity in these mice. These results indicate that protective antimalaria immunity induced by IrPySpz in MHC-I-Kd-Tg mice is mediated by CS protein-specific, Kd-restricted CD8+ T cells.

Combined administration of synthetic RNA and a conventional vaccine improves immune responses and protection against foot-and-mouth disease virus in swine.

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Borrego, Belén; Blanco, Esther; Rodríguez Pulido, Miguel; Mateos, Francisco; Lorenzo, Gema; Cardillo, Sabrina; Smitsaart, Eliana; Sobrino, Francisco; Sáiz, Margarita

2017-06-01

Foot-and-mouth disease virus (FMDV) is the causative agent of a highly contagious disease and a major concern in animal health worldwide. We have previously reported the use of RNA transcripts mimicking structural domains in the non-coding regions of the FMDV RNA as potent type-I interferon (IFN) inducers showing antiviral effect in vivo, as well as their immunomodulatory properties in combination with an FMD vaccine in mice. Here, we describe the enhancing effect of RNA delivery on the immunogenicity and protection induced by a suboptimal dose of a conventional FMD vaccine in pigs. Animals receiving the RNA developed earlier and higher levels of neutralizing antibodies against homologous and heterologous isolates, compared to those immunized with the vaccine alone, and had higher anti-FMDV titers at late times post-vaccination. RNA delivery also induced higher specific T-cell response and protection levels against FMDV challenge. Peripheral blood mononuclear cells from pigs inoculated with RNA and the vaccine had a higher IFN-γ specific response than those from pigs receiving the vaccine alone. When challenged with FMDV, all three animals immunized with the conventional vaccine developed antibodies to the non-structural viral proteins 3ABC and two of them developed severe signs of disease. In the group receiving the vaccine together with the RNA, two pigs were fully protected while one showed delayed and mild signs of disease. Our results support the immunomodulatory effect of these RNA molecules in natural hosts and suggest their potential use for improvement of FMD vaccines strategies. Copyright © 2017 Elsevier B.V. All rights reserved.

The C Terminus of the Core β-Ladder Domain in Japanese Encephalitis Virus Nonstructural Protein 1 Is Flexible for Accommodation of Heterologous Epitope Fusion.

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Yen, Li-Chen; Liao, Jia-Teh; Lee, Hwei-Jen; Chou, Wei-Yuan; Chen, Chun-Wei; Lin, Yi-Ling; Liao, Ching-Len

2016-02-01

NS1 is the only nonstructural protein that enters the lumen of the endoplasmic reticulum (ER), where NS1 is glycosylated, forms a dimer, and is subsequently secreted during flavivirus replication as dimers or hexamers, which appear to be highly immunogenic to the infected host, as protective immunity can be elicited against homologous flavivirus infections. Here, by using a trans-complementation assay, we identified the C-terminal end of NS1 derived from Japanese encephalitis virus (JEV), which was more flexible than other regions in terms of housing foreign epitopes without a significant impact on virus replication. This mapped flexible region is located in the conserved tip of the core β-ladder domain of the multimeric NS1 structure and is also known to contain certain linear epitopes, readily triggering specific antibody responses from the host. Despite becoming attenuated, recombinant JEV with insertion of a neutralizing epitope derived from enterovirus 71 (EV71) into the C-terminal end of NS1 not only could be normally released from infected cells, but also induced dual protective immunity for the host to counteract lethal challenge with either JEV or EV71 in neonatal mice. These results indicated that the secreted multimeric NS1 of flaviviruses may serve as a natural protein carrier to render epitopes of interest more immunogenic in the C terminus of the core β-ladder domain. The positive-sense RNA genomes of mosquito-borne flaviviruses appear to be flexible in terms of accommodating extra insertions of short heterologous antigens into their virus genes. Here, we illustrate that the newly identified C terminus of the core β-ladder domain in NS1 could be readily inserted into entities such as EV71 epitopes, and the resulting NS1-epitope fusion proteins appeared to maintain normal virus replication, secretion ability, and multimeric formation from infected cells. Nonetheless, such an insertion attenuated the recombinant JEV in mice, despite having retained

Prior mucosal exposure to heterologous cells alters the pathogenesis of cell-associated mucosal feline immunodeficiency virus challenge

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Leavell Sarah

2010-05-01

Full Text Available Abstract Background Several lines of research suggest that exposure to cellular material can alter the susceptibility to infection by HIV-1. Because sexual contact often includes exposure to cellular material, we hypothesized that repeated mucosal exposure to heterologous cells would induce an immune response that would alter the susceptibility to mucosal infection. Using the feline immunodeficiency virus (FIV model of HIV-1 mucosal transmission, the cervicovaginal mucosa was exposed once weekly for 12 weeks to 5,000 heterologous cells or media (control and then cats were vaginally challenged with cell-associated or cell-free FIV. Results Exposure to heterologous cells decreased the percentage of lymphocytes in the mucosal and systemic lymph nodes (LN expressing L-selectin as well as the percentage of CD4+ CD25+ T cells. These shifts were associated with enhanced ex-vivo proliferative responses to heterologous cells. Following mucosal challenge with cell-associated, but not cell-free, FIV, proviral burden was reduced by 64% in cats previously exposed to heterologous cells as compared to media exposed controls. Conclusions The pathogenesis and/or the threshold for mucosal infection by infected cells (but not cell-free virus can be modulated by mucosal exposure to uninfected heterologous cells.

[Specific humoral immunity after single immunization with mumps vaccine: data of a 3-year follow-up].

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Otrashevskaia, A V; Bukin, E K; Krasil'nikov, I V; Ignat'ev, G M

2011-01-01

The level and spectrum of humoral specific immunity were studied in 60 volunteers immunized with Russian mumps vaccine. Specific IgG levels were measured by enzyme immunoassay (EIA) and neutralization test using the Leningrad-3 (L-3) mumps virus (MV) vaccine strain and 5 heterologous MV strains of various genotypes (A, B, C, D, and H). The maximum functional activity of antibodies was recorded at an average of 18 months postvaccination. Within 3 years after vaccination, starting at 6 months, specific IgG neutralized all 6 MV strains having varying activity in relation to the genotype. Neutralizing titers (NT) against the L-3 strain were 1.3-1.7-fold higher than those against heterologous MV strains throughout the follow-up. Despite a tendency towards lower specific IgG levels, within 3 years postvaccination, EIA IgG titers remained to be 2.5 -log, L-3 strain HT were -log, or more, and the titers against 5 heterologous MV strains were 2 -log2 or more in all the volunteers.

Centralized Consensus Hemagglutinin Genes Induce Protective Immunity against H1, H3 and H5 Influenza Viruses.

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Richard J Webby

Full Text Available With the exception of the live attenuated influenza vaccine there have been no substantial changes in influenza vaccine strategies since the 1940's. Here we report an alternative vaccine approach that uses Adenovirus-vectored centralized hemagglutinin (HA genes as vaccine antigens. Consensus H1-Con, H3-Con and H5-Con HA genes were computationally derived. Mice were immunized with Ad vaccines expressing the centralized genes individually. Groups of mice were vaccinated with 1 X 1010, 5 X 107 and 1 X 107 virus particles per mouse to represent high, intermediate and low doses, respectively. 100% of the mice that were vaccinated with the high dose vaccine were protected from heterologous lethal challenges within each subtype. In addition to 100% survival, there were no signs of weight loss and disease in 7 out of 8 groups of high dose vaccinated mice. Lower doses of vaccine showed a reduction of protection in a dose-dependent manner. However, even the lowest dose of vaccine provided significant levels of protection against the divergent influenza strains, especially considering the stringency of the challenge virus. In addition, we found that all doses of H5-Con vaccine were capable of providing complete protection against mortality when challenged with lethal doses of all 3 H5N1 influenza strains. This data demonstrates that centralized H1-Con, H3-Con and H5-Con genes can be effectively used to completely protect mice against many diverse strains of influenza. Therefore, we believe that these Ad-vectored centralized genes could be easily translated into new human vaccines.

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

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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...... immunization had an effect on both Th1 and Th2 cytokines in caecal tonsils and Meckel's diverticulum. Thus both humoral and cellular immune responses are inducible by soluble A. galli antigen, but in this study no protection against the parasite was achieved....

Oral immunization of mice with gamma-irradiated Brucella neotomae induces protection against intraperitoneal and intranasal challenge with virulent B. abortus 2308.

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Dabral, Neha; Martha-Moreno-Lafont; Sriranganathan, Nammalwar; Vemulapalli, Ramesh

2014-01-01

Brucella spp. are Gram-negative, facultative intracellular coccobacilli that cause one of the most frequently encountered zoonosis worldwide. Humans naturally acquire infection through consumption of contaminated dairy and meat products and through direct exposure to aborted animal tissues and fluids. No vaccine against brucellosis is available for use in humans. In this study, we tested the ability of orally inoculated gamma-irradiated B. neotomae and B. abortus RB51 in a prime-boost immunization approach to induce antigen-specific humoral and cell mediated immunity and protection against challenge with virulent B. abortus 2308. Heterologous prime-boost vaccination with B. abortus RB51 and B. neotomae and homologous prime-boost vaccination of mice with B. neotomae led to the production of serum and mucosal antibodies specific to the smooth LPS. The elicited serum antibodies included the isotypes of IgM, IgG1, IgG2a, IgG2b and IgG3. All oral vaccination regimens induced antigen-specific CD4(+) and CD8(+) T cells capable of secreting IFN-γ and TNF-α. Upon intra-peritoneal challenge, mice vaccinated with B. neotomae showed the highest level of resistance against virulent B. abortus 2308 colonization in spleen and liver. Experiments with different doses of B. neotomae showed that all tested doses of 10(9), 10(10) and 10(11) CFU-equivalent conferred significant protection against the intra-peritoneal challenge. However, a dose of 10(11) CFU-equivalent of B. neotomae was required for affording protection against intranasal challenge as shown by the reduced bacterial colonization in spleens and lungs. Taken together, these results demonstrate the feasibility of using gamma-irradiated B. neotomae as an effective and safe oral vaccine to induce protection against respiratory and systemic infections with virulent Brucella.

Prime-boost vaccination with heterologous live vectors encoding SIV gag and multimeric HIV-1 gp160 protein: efficacy against repeated mucosal R5 clade C SHIV challenges.

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Lakhashe, Samir K; Velu, Vijayakumar; Sciaranghella, Gaia; Siddappa, Nagadenahalli B; Dipasquale, Janet M; Hemashettar, Girish; Yoon, John K; Rasmussen, Robert A; Yang, Feng; Lee, Sandra J; Montefiori, David C; Novembre, Francis J; Villinger, François; Amara, Rama Rao; Kahn, Maria; Hu, Shiu-Lok; Li, Sufen; Li, Zhongxia; Frankel, Fred R; Robert-Guroff, Marjorie; Johnson, Welkin E; Lieberman, Judy; Ruprecht, Ruth M

2011-08-05

We sought to induce primate immunodeficiency virus-specific cellular and neutralizing antibody (nAb) responses in rhesus macaques (RM) through a bimodal vaccine approach. RM were immunized intragastrically (i.g.) with the live-attenuated Listeria monocytogenes (Lm) vector Lmdd-BdopSIVgag encoding SIVmac239 gag. SIV Gag-specific cellular responses were boosted by intranasal and intratracheal administration of replication-competent adenovirus (Ad5hr-SIVgag) encoding the same gag. To broaden antiviral immunity, the RM were immunized with multimeric HIV clade C (HIV-C) gp160 and HIV Tat. SIV Gag-specific cellular immune responses and HIV-1 nAb developed in some RM. The animals were challenged intrarectally with five low doses of R5 SHIV-1157ipEL-p, encoding a heterologous HIV-C Env (22.1% divergent to the Env immunogen). All five controls became viremic. One out of ten vaccinees was completely protected and another had low peak viremia. Sera from the completely and partially protected RM neutralized the challenge virus > 90%; these RM also had strong SIV Gag-specific proliferation of CD8⁺ T cells. Peak and area under the curve of plasma viremia (during acute phase) among vaccinees was lower than for controls, but did not attain significance. The completely protected RM showed persistently low numbers of the α4β7-expressing CD4⁺ T cells; the latter have been implicated as preferential virus targets in vivo. Thus, vaccine-induced immune responses and relatively lower numbers of potential target cells were associated with protection. Copyright © 2011 Elsevier Ltd. All rights reserved.

A prophylactic multivalent vaccine against different filovirus species is immunogenic and provides protection from lethal infections with Ebolavirus and Marburgvirus species in non-human primates.

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Benoit Callendret

Full Text Available The search for a universal filovirus vaccine that provides protection against multiple filovirus species has been prompted by sporadic but highly lethal outbreaks of Ebolavirus and Marburgvirus infections. A good prophylactic vaccine should be able to provide protection to all known filovirus species and as an upside potentially protect from newly emerging virus strains. We investigated the immunogenicity and protection elicited by multivalent vaccines expressing glycoproteins (GP from Ebola virus (EBOV, Sudan virus (SUDV, Taï Forest virus (TAFV and Marburg virus (MARV. Immune responses against filovirus GP have been associated with protection from disease. The GP antigens were expressed by adenovirus serotypes 26 and 35 (Ad26 and Ad35 and modified Vaccinia virus Ankara (MVA vectors, all selected for their strong immunogenicity and good safety profile. Using fully lethal NHP intramuscular challenge models, we assessed different vaccination regimens for immunogenicity and protection from filovirus disease. Heterologous multivalent Ad26-Ad35 prime-boost vaccination regimens could give full protection against MARV (range 75%-100% protection and EBOV (range 50% to 100% challenge, and partial protection (75% against SUDV challenge. Heterologous multivalent Ad26-MVA prime-boost immunization gave full protection against EBOV challenge in a small cohort study. The use of such multivalent vaccines did not show overt immune interference in comparison with monovalent vaccines. Multivalent vaccines induced GP-specific antibody responses and cellular IFNγ responses to each GP expressed by the vaccine, and cross-reactivity to TAFV GP was detected in a trivalent vaccine expressing GP from EBOV, SUDV and MARV. In the EBOV challenge studies, higher humoral EBOV GP-specific immune responses (p = 0.0004 were associated with survival from EBOV challenge and less so for cellular immune responses (p = 0.0320. These results demonstrate that it is feasible to

A prophylactic multivalent vaccine against different filovirus species is immunogenic and provides protection from lethal infections with Ebolavirus and Marburgvirus species in non-human primates.

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Callendret, Benoit; Vellinga, Jort; Wunderlich, Kerstin; Rodriguez, Ariane; Steigerwald, Robin; Dirmeier, Ulrike; Cheminay, Cedric; Volkmann, Ariane; Brasel, Trevor; Carrion, Ricardo; Giavedoni, Luis D; Patterson, Jean L; Mire, Chad E; Geisbert, Thomas W; Hooper, Jay W; Weijtens, Mo; Hartkoorn-Pasma, Jutta; Custers, Jerome; Grazia Pau, Maria; Schuitemaker, Hanneke; Zahn, Roland

2018-01-01

The search for a universal filovirus vaccine that provides protection against multiple filovirus species has been prompted by sporadic but highly lethal outbreaks of Ebolavirus and Marburgvirus infections. A good prophylactic vaccine should be able to provide protection to all known filovirus species and as an upside potentially protect from newly emerging virus strains. We investigated the immunogenicity and protection elicited by multivalent vaccines expressing glycoproteins (GP) from Ebola virus (EBOV), Sudan virus (SUDV), Taï Forest virus (TAFV) and Marburg virus (MARV). Immune responses against filovirus GP have been associated with protection from disease. The GP antigens were expressed by adenovirus serotypes 26 and 35 (Ad26 and Ad35) and modified Vaccinia virus Ankara (MVA) vectors, all selected for their strong immunogenicity and good safety profile. Using fully lethal NHP intramuscular challenge models, we assessed different vaccination regimens for immunogenicity and protection from filovirus disease. Heterologous multivalent Ad26-Ad35 prime-boost vaccination regimens could give full protection against MARV (range 75%-100% protection) and EBOV (range 50% to 100%) challenge, and partial protection (75%) against SUDV challenge. Heterologous multivalent Ad26-MVA prime-boost immunization gave full protection against EBOV challenge in a small cohort study. The use of such multivalent vaccines did not show overt immune interference in comparison with monovalent vaccines. Multivalent vaccines induced GP-specific antibody responses and cellular IFNγ responses to each GP expressed by the vaccine, and cross-reactivity to TAFV GP was detected in a trivalent vaccine expressing GP from EBOV, SUDV and MARV. In the EBOV challenge studies, higher humoral EBOV GP-specific immune responses (p = 0.0004) were associated with survival from EBOV challenge and less so for cellular immune responses (p = 0.0320). These results demonstrate that it is feasible to generate a

Immunization with the recombinant antigen Ss-IR induces protective immunity to infection with Strongyloides stercoralis in mice.

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Abraham, David; Hess, Jessica A; Mejia, Rojelio; Nolan, Thomas J; Lok, James B; Lustigman, Sara; Nutman, Thomas B

2011-10-19

Human intestinal infections with the nematode Strongyloides stercoralis remain a significant problem worldwide and a vaccine would be a useful addition to the tools available to prevent and control this infection. The goal of this study was to test single antigens for their efficacy in a vaccine against S. stercoralis larvae in mice. Alum was used as the adjuvant in these studies and antigens selected for analysis were either recognized by protective human IgG (Ss-TMY-1, Ss-EAT-6, and Ss-LEC-5) or were known to be highly immunogenic in humans (Ss-NIE-1 and Ss-IR). Only mice immunized with the Ss-IR antigen demonstrated a significant decrease of approximately 80% in the survival of larval parasites in the challenge infection. Antibodies, recovered from mice with protective immunity to S. stercoralis after immunization with Ss-IR, were used to locate the antigen in the larvae. Confocal microscopy revealed that IgG from mice immunized with Ss-IR bound to the surface of the parasites and observations by electron microscopy indicated that IgG bound to granules in the glandular esophagus. Serum collected from mice immunized with Ss-IR passively transferred immunity to naïve mice. These studies demonstrate that Ss-IR, in combination with alum, induces high levels of protective immunity through an antibody dependent mechanism and may therefore be suitable for further development as a vaccine against human strongyloidiasis. Copyright © 2011 Elsevier Ltd. All rights reserved.

Immunization of C57BL/6 Mice with GRA2 Combined with MPL Conferred Partial Immune Protection against Toxoplasma gondii

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Babaie, Jalal; Amiri, Samira; Homayoun, Robab; Azimi, Ebrahim; Mohabati, Reyhaneh; Berizi, Mahboobe; Sadaie, M. Reza; Golkar, Majid

2018-01-01

We have previously reported that immunization with GRA2 antigen of Toxoplasma gondii induces protective immunity in CBA/J (H2k) and BALB/c mice (H2d). We aimed to examine whether immunization of a distinct strain of rodent with recombinant dense granule antigens (GRA2) combined with monophosphorryl lipid A (MPL) adjuvant elicits protective immune response against T. gondii. C57BL/6 (H2b haplotype) mice were immunized with GRA2, formulated in MPL adjuvant. Strong humoral response, predominantly of IgG1 subclass and cellular response, IFN-γ, was detected at three weeks post immunization. Mice immunized with GRA2 had significantly (p < 0.01) fewer brain cysts than those in the adjuvant group, upon challenge infection. Despite the production of a strong antibody response, IFN-γ production and brain cyst reduction were not significant when the immunized mice were infected four months after the immunization. We can conclude that GRA2 immunization partially protects against T. gondii infection in C57BL/6 mice, though the potency and longevity of this antigen as a standalone vaccine may vary in distinct genetic backgrounds. This observation further emphasizes the utility of GRA2 for incorporation into a multi-antigenic vaccine against T. gondii.

Distributed Computations Environment Protection Using Artificial Immune Systems

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A. V. Moiseev

2011-12-01

Full Text Available In this article the authors describe possibility of artificial immune systems applying for distributed computations environment protection from definite types of malicious impacts.

Induction of protective immunity against toxoplasmosis in mice by ...

African Journals Online (AJOL)

The results showed that mice immunized by pcROP1 with or without alum produced high Th1 immune response compared with control groups. This type of DNA vaccine prolonged slightly the survival time. The current study showed that ROP1 DNA vaccine can induced partial protective response against toxoplasmosis.

Mucosal vaccination with heterologous viral vectored vaccine targeting subdominant SIV accessory antigens strongly inhibits early viral replication

DEFF Research Database (Denmark)

Xu, Huanbin; Andersson, Anne-Marie Carola; Ragonnaud, Emeline

2017-01-01

Conventional HIV T cell vaccine strategies have not been successful in containing acute peak viremia, nor in providing long-term control. We immunized rhesus macaques intramuscularly and rectally using a heterologous adenovirus vectored SIV vaccine regimen encoding normally weakly immunogenic tat...

Protective immunity to UV radiation-induced skin tumours induced by skin grafts and epidermal cells

International Nuclear Information System (INIS)

Ronald Sluyter; Kylie S Yuen; Gary M Halliday

2001-01-01

There is little evidence that cutaneous dendritic cells (DC), including epidermal Langerhans cells (LC), can induce immunity to UV radiation (UVR)-induced skin tumours. Here, it is shown that cells within skin can induce protective antitumour immunity against a UVR-induced fibrosarcoma. Transplantation of the skin overlying subcutaneous tumours onto naive recipients could induce protective antitumour immunity, probably because the grafting stimulated the tumour Ag-loaded DC to migrate to local lymph nodes. This suggests that cutaneous APC can present tumour Ag to induce protective antitumour immunity. Previously, it has been shown that immunization of mice with MHC class II+ epidermal cells (EC) pulsed with tumour extracts could induce delayed-type hypersensitivity against tumour cells. Here, this same immunization protocol could induce protective immunity against a minimum tumorigenic dose of UVR-induced fibrosarcoma cells, but not higher doses. Epidermal cells obtained from semiallogeneic donors and pulsed with tumour extract could also induce protective immunity. However, presentation of BSA Ag from the culture medium was found to contribute to this result using semiallogeneic EC. The results suggest that LC overlying skin tumours may be able to induce protective immunity to UVR-induced tumours if stimulated to migrate from the skin. Copyright (2001) Australasian Society of Immunology Inc

The induction of species-specific immunity against Schistosoma japonicum by exposure of rats to ultra-violet attenuated cercariae

International Nuclear Information System (INIS)

Moloney, N.A.; Webbe, G.; Hinchcliffe, P.

1987-01-01

Single percutaneous immunizations of Fischer rats with 1000 ultra-violet attenuated Schistosoma japonicum cercariae induced 52-88% resistance to challenge 4 weeks later. Increasing this to 3 immunizations induced 90% resistance to challenge, and this level of protection remained undiminished for up to 40 weeks after vaccination. Rats vaccinated with gamma-irradiated S. mansoni cercariae were resistant to challenge with S. mansoni but not S. japonicum. Similarly rats vaccinated with u.v.-attenuated S. japonicum cercariae were not resistant to heterologous challenge. Thus irradiated vaccines are species-specific in both permissive and non-permissive hosts. (author)

Boosting BCG-primed responses with a subunit Apa vaccine during the waning phase improves immunity and imparts protection against Mycobacterium tuberculosis.

Science.gov (United States)

Nandakumar, Subhadra; Kannanganat, Sunil; Dobos, Karen M; Lucas, Megan; Spencer, John S; Amara, Rama Rao; Plikaytis, Bonnie B; Posey, James E; Sable, Suraj B

2016-05-13

Heterologous prime-boosting has emerged as a powerful vaccination approach against tuberculosis. However, optimal timing to boost BCG-immunity using subunit vaccines remains unclear in clinical trials. Here, we followed the adhesin Apa-specific T-cell responses in BCG-primed mice and investigated its BCG-booster potential. The Apa-specific T-cell response peaked 32-52 weeks after parenteral or mucosal BCG-priming but waned significantly by 78 weeks. A subunit-Apa-boost during the contraction-phase of BCG-response had a greater effect on the magnitude and functional quality of specific cellular and humoral responses compared to a boost at the peak of BCG-response. The cellular response increased following mucosal BCG-prime-Apa-subunit-boost strategy compared to Apa-subunit-prime-BCG-boost approach. However, parenteral BCG-prime-Apa-subunit-boost by a homologous route was the most effective strategy in-terms of enhancing specific T-cell responses during waning in the lung and spleen. Two Apa-boosters markedly improved waning BCG-immunity and significantly reduced Mycobacterium tuberculosis burdens post-challenge. Our results highlight the challenges of optimization of prime-boost regimens in mice where BCG drives persistent immune-activation and suggest that boosting with a heterologous vaccine may be ideal once the specific persisting effector responses are contracted. Our results have important implications for design of prime-boost regimens against tuberculosis in humans.

"The Impact of Mycobacterium tuberculosis Immune Evasion on Protective Immunity: Implications for TB Vaccine Design" - Meeting report.

Science.gov (United States)

Boggiano, Cesar; Eichelberg, Katrin; Ramachandra, Lakshmi; Shea, Jaqueline; Ramakrishnan, Lalita; Behar, Samuel; Ernst, Joel D; Porcelli, Steven A; Maeurer, Markus; Kornfeld, Hardy

2017-06-14

Tuberculosis (TB) is the major cause of death from infectious diseases around the world, particularly in HIV infected individuals. TB vaccine design and development have been focused on improving Bacille Calmette-Guérin (BCG) and evaluating recombinant and viral vector expressed Mycobacterium tuberculosis (Mtb) proteins, for boosting BCG-primed immunity, but these approaches have not yet yielded significant improvements over the modest effects of BCG in protecting against infection or disease. On March 7-8, 2016, the National Institute of Allergy and Infectious Diseases (NIAID) convened a workshop on "The Impact of Mtb Immune Evasion on Protective Immunity: Implications for TB Vaccine Design" with the goal of defining immune mechanisms that could be targeted through novel research approaches, to inform vaccine design and immune therapeutic interventions for prevention of TB. The workshop addressed early infection events, the impact of Mtb evolution on the development and maintenance of an adaptive immune response, and the factors that influence protection against and progression to active disease. Scientific gaps and areas of study to revitalize and accelerate TB vaccine design were discussed and prioritized. These included a comprehensive evaluation of innate and Mtb-specific adaptive immune responses in the lung at different stages of disease; determining the role of B cells and antibodies (Abs) during Mtb infection; development of better assays to measure Mtb burden following exposure, infection, during latency and after treatment, and approaches to improving current animal models to study Mtb immunogenicity, TB disease and transmission. Copyright © 2017.

The heterologous expression strategies of antimicrobial peptides in microbial systems.

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Deng, Ting; Ge, Haoran; He, Huahua; Liu, Yao; Zhai, Chao; Feng, Liang; Yi, Li

2017-12-01

Antimicrobial peptides (AMPs) consist of molecules acting on the defense systems of numerous organisms toward tumor and multiple pathogens, such as bacteria, fungi, viruses, and parasites. Compared to traditional antibiotics, AMPs are more stable and have lower propensity for developing resistance through functioning in the innate immune system, thus having important applications in the fields of medicine, food and so on. However, despite of their high economic values, the low yield and the cumbersome extraction process in AMPs production are problems that limit their industrial application and scientific research. To conquer these obstacles, optimized heterologous expression technologies were developed that could provide effective ways to increase the yield of AMPs. In this review, the research progress on heterologous expression of AMPs using Escherichia coli, Bacillus subtilis, Pichia pastoris and Saccharomyces cerevisiae as host cells was mainly summarized, which might guide the expression strategies of AMPs in these cells. Copyright © 2017 Elsevier Inc. All rights reserved.

Heterologous expression of antigenic peptides in Bacillus subtilis biofilms.

Science.gov (United States)

Vogt, Cédric M; Schraner, Elisabeth M; Aguilar, Claudio; Eichwald, Catherine

2016-08-11

Numerous strategies have been developed for the display of heterologous proteins in the surface of live bacterial carriers, which can be used as vaccines, immune-modulators, cancer therapy or bioremediation. Bacterial biofilms have emerged as an interesting approach for the expression of proteins of interest. Bacillus subtilis is a well-described, endospore-forming organism that is able to form biofilms and also used as a probiotic, thus making it a suitable candidate for the display of heterologous proteins within the biofilm. Here, we describe the use of TasA, an important structural component of the biofilms formed by B. subtilis, as a genetic tool for the display of heterologous proteins. We first engineered the fusion protein TasA-mCherry and showed that was widely deployed within the B. subtilis biofilms. A significant enhancement of the expression of TasA-mCherry within the biofilm was obtained when depleting both tasA and sinR genes. We subsequently engineered fusion proteins of TasA to antigenic peptides of the E. granulosus parasite, paramyosin and tropomyosin. Our results show that the antigens were well expressed within the biofilm as denoted by macrostructure complementation and by the detection of the fusion protein in both immunoblot and immunohistochemistry. In addition, we show that the recombinant endospores of B. subtilis preserve their biophysical and morphological properties. In this work we provide strong evidence pointing that TasA is a suitable candidate for the display of heterologous peptides, such as antigens, cytokines, enzymes or antibodies, in the B. subtilis biofilms. Finally, our data portray that the recombinant endospores preserve their morphological and biophysical properties and could be an excellent tool to facilitate the transport and the administration.

Eosinophils mediate protective immunity against secondary nematode infection.

Science.gov (United States)

Huang, Lu; Gebreselassie, Nebiat G; Gagliardo, Lucille F; Ruyechan, Maura C; Luber, Kierstin L; Lee, Nancy A; Lee, James J; Appleton, Judith A

2015-01-01

Eosinophils are versatile cells that regulate innate and adaptive immunity, influence metabolism and tissue repair, and contribute to allergic lung disease. Within the context of immunity to parasitic worm infections, eosinophils are prominent yet highly varied in function. We have shown previously that when mice undergo primary infection with the parasitic nematode Trichinella spiralis, eosinophils play an important immune regulatory role that promotes larval growth and survival in skeletal muscle. In this study, we aimed to address the function of eosinophils in secondary infection with T. spiralis. By infecting eosinophil-ablated mice, we found that eosinophils are dispensable for immunity that clears adult worms or controls fecundity in secondary infection. In contrast, eosinophil ablation had a pronounced effect on secondary infection of skeletal muscle by migratory newborn larvae. Restoring eosinophils to previously infected, ablated mice caused them to limit muscle larvae burdens. Passive immunization of naive, ablated mice with sera or Ig from infected donors, together with transfer of eosinophils, served to limit the number of newborn larvae that migrated in tissue and colonized skeletal muscle. Results from these in vivo studies are consistent with earlier findings that eosinophils bind to larvae in the presence of Abs in vitro. Although our previous findings showed that eosinophils protect the parasite in primary infection, these new data show that eosinophils protect the host in secondary infection. Copyright © 2014 by The American Association of Immunologists, Inc.

Priming T-cell responses with recombinant measles vaccine vector in a heterologous prime-boost setting in non-human primates.

Science.gov (United States)

Bolton, Diane L; Santra, Sampa; Swett-Tapia, Cindy; Custers, Jerome; Song, Kaimei; Balachandran, Harikrishnan; Mach, Linh; Naim, Hussein; Kozlowski, Pamela A; Lifton, Michelle; Goudsmit, Jaap; Letvin, Norman; Roederer, Mario; Radošević, Katarina

2012-09-07

Licensed live attenuated virus vaccines capable of expressing transgenes from other pathogens have the potential to reduce the number of childhood immunizations by eliciting robust immunity to multiple pathogens simultaneously. Recombinant attenuated measles virus (rMV) derived from the Edmonston Zagreb vaccine strain was engineered to express simian immunodeficiency virus (SIV) Gag protein for the purpose of evaluating the immunogenicity of rMV as a vaccine vector in rhesus macaques. rMV-Gag immunization alone elicited robust measles-specific humoral and cellular responses, but failed to elicit transgene (Gag)-specific immune responses, following aerosol or intratracheal/intramuscular delivery. However, when administered as a priming vaccine to a heterologous boost with recombinant adenovirus serotype 5 expressing the same transgene, rMV-Gag significantly enhanced Gag-specific T lymphocyte responses following rAd5 immunization. Gag-specific humoral responses were not enhanced, however, which may be due to either the transgene or the vector. Cellular response priming by rMV against the transgene was highly effective even when using a suboptimal dose of rAd5 for the boost. These data demonstrate feasibility of using rMV as a priming component of heterologous prime-boost vaccine regimens for pathogens requiring strong cellular responses. Copyright © 2012 Elsevier Ltd. All rights reserved.

Antibody induced by immunization with the Jeryl Lynn mumps vaccine strain effectively neutralizes a heterologous wild-type mumps virus associated with a large outbreak.

Science.gov (United States)

Rubin, Steven A; Qi, Li; Audet, Susette A; Sullivan, Bradley; Carbone, Kathryn M; Bellini, William J; Rota, Paul A; Sirota, Lev; Beeler, Judy

2008-08-15

Recent mumps outbreaks in older vaccinated populations were caused primarily by genotype G viruses, which are phylogenetically distinct from the genotype A vaccine strains used in the countries affected by the outbreaks. This finding suggests that genotype A vaccine strains could have reduced efficacy against heterologous mumps viruses. The remote history of vaccination also suggests that waning immunity could have contributed to susceptibility. To examine these issues, we obtained consecutive serum samples from children at different intervals after vaccination and assayed the ability of these samples to neutralize the genotype A Jeryl Lynn mumps virus vaccine strain and a genotype G wild-type virus obtained during the mumps outbreak that occurred in the United States in 2006. Although the geometric mean neutralizing antibody titers against the genotype G virus were approximately one-half the titers measured against the vaccine strain, and although titers to both viruses decreased with time after vaccination, antibody induced by immunization with the Jeryl Lynn mumps vaccine strain effectively neutralized the outbreak-associated virus at all time points tested.

Vector optimization and needle-free intradermal application of a broadly protective polyvalent influenza A DNA vaccine for pigs and humans

DEFF Research Database (Denmark)

Borggren, Marie; Nielsen, Jens; Bragstad, Karoline

2015-01-01

such as the induction of cellular and humoral immunity, inherent safety and rapid production time. We have previously developed a DNA vaccine encoding selected influenza proteins of pandemic origin and demonstrated broad protective immune responses in ferrets and pigs. In this study, we evaluated our DNA vaccine......The threat posed by the 2009 pandemic H1N1 virus emphasized the need for new influenza A virus vaccines inducing a broad cross-protective immune response for use in both humans and pigs. An effective and broad influenza vaccine for pigs would greatly benefit the pork industry and contribute...... to public health by diminishing the risk of emerging highly pathogenic reassortants. Current inactivated protein vaccines against swine influenza produce only short-lived immunity and have no efficacy against heterologous strains. DNA vaccines are a potential alternative with advantages...

Impact of pre-existing MSP142-allele specific immunity on potency of an erythrocytic Plasmodium falciparum vaccine

Directory of Open Access Journals (Sweden)

Bergmann-Leitner Elke S

2012-09-01

Full Text Available Abstract Background MSP1 is the major surface protein on merozoites and a prime candidate for a blood stage malaria vaccine. Preclinical and seroepidemiological studies have implicated antibodies to MSP1 in protection against blood stage parasitaemia and/or reduced parasite densities, respectively. Malaria endemic areas have multiple strains of Plasmodium falciparum circulating at any given time, giving rise to complex immune responses, an issue which is generally not addressed in clinical trials conducted in non-endemic areas. A lack of understanding of the effect of pre-existing immunity to heterologous parasite strains may significantly contribute to vaccine failure in the field. The purpose of this study was to model the effect of pre-existing immunity to MSP142 on the immunogenicity of blood-stage malaria vaccines based on alternative MSP1 alleles. Methods Inbred and outbred mice were immunized with various recombinant P. falciparum MSP142 proteins that represent the two major alleles of MSP142, MAD20 (3D7 and Wellcome (K1, FVO. Humoral immune responses were analysed by ELISA and LuminexTM, and functional activity of induced MSP142-specific antibodies was assessed by growth inhibition assays. T-cell responses were characterized using ex vivo ELISpot assays. Results Analysis of the immune responses induced by various immunization regimens demonstrated a strong allele-specific response at the T cell level in both inbred and outbred mice. The success of heterologous regimens depended on the degree of homology of the N-terminal p33 portion of the MSP142, likely due to the fact that most T cell epitopes reside in this part of the molecule. Analysis of humoral immune responses revealed a marked cross-reactivity between the alleles. Functional analyses showed that some of the heterologous regimens induced antibodies with improved growth inhibitory activities. Conclusion The development of a more broadly efficacious MSP1 based vaccine may be

Booster vaccination with safe, modified, live-attenuated mutants of Brucella abortus strain RB51 vaccine confers protective immunity against virulent strains of B. abortus and Brucella canis in BALB/c mice.

Science.gov (United States)

Truong, Quang Lam; Cho, Youngjae; Kim, Kiju; Park, Bo-Kyoung; Hahn, Tae-Wook

2015-11-01

Brucella abortus attenuated strain RB51 vaccine (RB51) is widely used in prevention of bovine brucellosis. Although vaccination with this strain has been shown to be effective in conferring protection against bovine brucellosis, RB51 has several drawbacks, including residual virulence for animals and humans. Therefore, a safe and efficacious vaccine is needed to overcome these disadvantages. In this study, we constructed several gene deletion mutants (ΔcydC, ΔcydD and ΔpurD single mutants, and ΔcydCΔcydD and ΔcydCΔpurD double mutants) of RB51 with the aim of increasing the safety of the possible use of these mutants as vaccine candidates. The RB51ΔcydC, RB51ΔcydD, RB51ΔpurD, RB51ΔcydCΔcydD and RB51ΔcydCΔpurD mutants exhibited significant attenuation of virulence when assayed in murine macrophages in vitro or in BALB/c mice. A single intraperitoneal immunization with RB51ΔcydC, RB51ΔcydD, RB51ΔcydCΔcydD or RB51ΔcydCΔpurD mutants was rapidly cleared from mice within 3 weeks, whereas the RB51ΔpurD mutant and RB51 were detectable in spleens until 4 and 7 weeks, respectively. Vaccination with a single dose of RB51 mutants induced lower protective immunity in mice than did parental RB51. However, a booster dose of these mutants provided significant levels of protection in mice against challenge with either the virulent homologous B. abortus strain 2308 or the heterologous Brucella canis strain 26. In addition, these mutants were found to induce a mixed but T-helper-1-biased humoral and cellular immune response in immunized mice. These data suggest that immunization with a booster dose of attenuated RB51 mutants provides an attractive strategy to protect against either bovine or canine brucellosis.

Mucosal delivery of a vectored RSV vaccine is safe and elicits protective immunity in rodents and nonhuman primates

Directory of Open Access Journals (Sweden)

Angiolo Pierantoni

Full Text Available Respiratory Syncytial Virus (RSV is a leading cause of severe respiratory disease in infants and the elderly. No vaccine is presently available to address this major unmet medical need. We generated a new genetic vaccine based on chimpanzee Adenovirus (PanAd3-RSV and Modified Vaccinia Ankara RSV (MVA-RSV encoding the F, N, and M2-1 proteins of RSV, for the induction of neutralizing antibodies and broad cellular immunity. Because RSV infection is restricted to the respiratory tract, we compared intranasal (IN and intramuscular (M administration for safety, immunogenicity, and efficacy in different species. A single IN or IM vaccination completely protected BALB/c mice and cotton rats against RSV replication in the lungs. However, only IN administration could prevent infection in the upper respiratory tract. IM vaccination with MVA-RSV also protected cotton rats from lower respiratory tract infection in the absence of detectable neutralizing antibodies. Heterologous prime boost with PanAd3-RSV and MVA-RSV elicited high neutralizing antibody titers and broad T-cell responses in nonhuman primates. In addition, animals primed in the nose developed mucosal IgA against the F protein. In conclusion, we have shown that our vectored RSV vaccine induces potent cellular and humoral responses in a primate model, providing strong support for clinical testing.

Humoral immunity through immunoglobulin M protects mice from an experimental actinomycetoma infection by Nocardia brasiliensis.

Science.gov (United States)

Salinas-Carmona, Mario C; Pérez-Rivera, Isabel

2004-10-01

An experimental model of infection with Nocardia brasiliensis, used as an example of a facultative intracellular pathogen, was tested. N. brasiliensis was injected into the rear foot pads of BALB/c mice to establish an infection. Within 30 days, infected animals developed a chronic actinomycetoma infection. Batch cultures of N. brasiliensis were used to purify P61, P38, and P24 antigens; P61 is a catalase, and P38 is a protease with strong caseinolytic activity. Active and passive immunizations of BALB/c mice with these three purified soluble antigens were studied. Protection was demonstrated for actively immunized mice. However, immunity lasted only 30 days. Other groups of immunized mice were bled at different times, and their sera were passively transferred to naive recipients that were then infected with N. brasiliensis. Sera collected 5, 6, and 7 days after donor immunization conferred complete, long-lasting protection. The protective effect of passive immunity decreased when sera were collected 2 weeks after donor immunization. However, neither the early sera (1-, 2-, and 3-day sera) nor the later sera (30- or 45-day sera) prevented the infection. Hyperimmune sera with the highest levels of immunoglobulin G (IgG) to N. brasiliensis antigens did not protect at all. The antigens tested induced two IgM peaks. The first peak was present 3 days after immunization but was not antigen specific and did not transfer protection. The second peak was evident 7 days after immunization, was an IgM response, was antigen specific, and conferred protection. This results clearly demonstrate that IgM antibodies protect the host against a facultative intracellular bacterium.

The efficacy of chimeric vaccines constructed with PEP-1 and Ii-Key linking to a hybrid epitope from heterologous viruses.

Science.gov (United States)

Liu, Xue-lan; Shan, Wen-jie; Xu, Shan-shan; Zhang, Jin-jing; Xu, Fa-zhi; Xia, Sheng-lin; Dai, Yin

2015-09-01

The heterologous epitope-peptide from different viruses may represent an attractive candidate vaccine. In order to evaluate the role of cell-permeable peptide (PEP-1) and Ii-Key moiety from the invariant chain (Ii) of MHC on the heterologous peptide chimeras, we linked the two vehicles to hybrid epitopes on the VP2 protein (aa197-209) of the infectious bursal disease virus and HN protein (aa345-353) of the Newcastle disease virus. The chimeric vaccines were prepared and injected into mice. The immune effects were measured by indirect ELISA. The results showed that the vehicle(s) could significantly boost immune effects against the heterologous epitope peptide. The Ii-Key-only carrier induced more effective immunological responses, compared with the PEP-1 and Ii-Key hybrid vehicle. The carrier-peptide hybrids all showed strong colocalization with major histocompatibility complex (MHC) class II molecules compared with the epitope-peptide (weakly-binding) after co-transfection into 293T cells. Together, our results lay the groundwork for designing new hybrid vaccines based on Ii-Key and/or PEP-1 peptides. Copyright © 2015 The International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

VAR2CSA and protective immunity against pregnancy-associated Plasmodium falciparum malaria

DEFF Research Database (Denmark)

Hviid, L; Salanti, A

2007-01-01

People living in areas with stable transmission of P. falciparum parasites acquire protective immunity to malaria over a number of years and following multiple disease episodes. Immunity acquired this way is mediated by IgG with specificity for parasite-encoded, clonally variant surface antigens...... that the selective placental accumulation of IEs that characterizes pregnancy-associated malaria (PAM) is caused by an immunologically and functionally unique subset of VSA (VSAPAM) that is only expressed by parasites infecting pregnant women, and that protective immunity to PAM is mediated by IgG with specificity...

Protective immunity by oral immunization with heat-killed Shigella strains in a guinea pig colitis model.

Science.gov (United States)

Barman, Soumik; Koley, Hemanta; Ramamurthy, Thandavarayan; Chakrabarti, Manoj Kumar; Shinoda, Sumio; Nair, Gopinath Balakrish; Takeda, Yoshifumi

2013-11-01

The protective efficacy of and immune response to heat-killed cells of monovalent and hexavalent mixtures of six serogroups/serotypes of Shigella strains (Shigella dysenteriae 1, Shigella flexneri 2a, S. flexneri 3a, S. flexneri 6, Shigella boydii 4, and Shigella sonnei) were examined in a guinea pig colitis model. A monovalent or hexavalent mixture containing 1 × 10(7) of each serogroup/serotype of heat-killed Shigella cells was administered orally on Days 0, 7, 14 and 21. On Day 28, the immunized animals were challenged rectally with 1 × 10(9) live virulent cells of each of the six Shigella serogroups/serotypes. In all immunized groups, significant levels of protection were observed after these challenges. The serum titers of IgG and IgA against the lipopolysaccharide of each of the six Shigella serogroups/serotypes increased exponential during the course of immunization. High IgA titers against the lipopolysaccharide of each of the six Shigella serogroups/serotypes were also observed in intestinal lavage fluid from all immunized animals. These data indicate that a hexavalent mixture of heat-killed cells of the six Shigella serogroups/serotypes studied would be a possible broad-spectrum candidate vaccine against shigellosis. © 2013 The Societies and Wiley Publishing Asia Pty Ltd.

Room Temperature Stable PspA-Based Nanovaccine Induces Protective Immunity

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Danielle A. Wagner-Muñiz

2018-03-01

Full Text Available Streptococcus pneumoniae is a major causative agent of pneumonia, a debilitating disease particularly in young and elderly populations, and is the leading worldwide cause of death in children under the age of five. While there are existing vaccines against S. pneumoniae, none are protective across all serotypes. Pneumococcal surface protein A (PspA, a key virulence factor of S. pneumoniae, is an antigen that may be incorporated into future vaccines to address the immunological challenges presented by the diversity of capsular antigens. PspA has been shown to be immunogenic and capable of initiating a humoral immune response that is reactive across approximately 94% of pneumococcal strains. Biodegradable polyanhydrides have been studied as a nanoparticle-based vaccine (i.e., nanovaccine platform to stabilize labile proteins, to provide adjuvanticity, and enhance patient compliance by providing protective immunity in a single dose. In this study, we designed a room temperature stable PspA-based polyanhydride nanovaccine that eliminated the need for a free protein component (i.e., 100% encapsulated within the nanoparticles. Mice were immunized once with the lead nanovaccine and upon challenge, presented significantly higher survival rates than animals immunized with soluble protein alone, even with a 25-fold reduction in protein dose. This lead nanovaccine formulation performed similarly to protein adjuvanted with Alum, however, with much less tissue reactogenicity at the site of immunization. By eliminating the free PspA from the nanovaccine formulation, the lead nanovaccine was efficacious after being stored dry for 60 days at room temperature, breaking the need for maintaining the cold chain. Altogether, this study demonstrated that a single dose PspA-based nanovaccine against S. pneumoniae induced protective immunity and provided thermal stability when stored at room temperature for at least 60 days.

Immunity to Babesia in mice I. Adoptive transfer of immunity to Babesia rodhaini with immune spleen cells and the effect of irradiation on the protection of immune mice

NARCIS (Netherlands)

Kuil, H.; Zivkovic, D.; Seinen, W.; Albers-van Bemmel, C.M.G.; Speksnijder, J.E.

1984-01-01

Immunisation of Balb/c mice against Babesia rodhaini by an amicarbalide- controlled infection resulted in a solid immunity which lasted for 216 days. With spleen cells of immune mice protection could be transferred both to naive mice pretreated with cyclophosphamide. Treatment of naive mice with

Induction and Subversion of Human Protective Immunity: Contrasting Influenza and Respiratory Syncytial Virus

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Stephanie Ascough

2018-03-01

Full Text Available Respiratory syncytial virus (RSV and influenza are among the most important causes of severe respiratory disease worldwide. Despite the clinical need, barriers to developing reliably effective vaccines against these viruses have remained firmly in place for decades. Overcoming these hurdles requires better understanding of human immunity and the strategies by which these pathogens evade it. Although superficially similar, the virology and host response to RSV and influenza are strikingly distinct. Influenza induces robust strain-specific immunity following natural infection, although protection by current vaccines is short-lived. In contrast, even strain-specific protection is incomplete after RSV and there are currently no licensed RSV vaccines. Although animal models have been critical for developing a fundamental understanding of antiviral immunity, extrapolating to human disease has been problematic. It is only with recent translational advances (such as controlled human infection models and high-dimensional technologies that the mechanisms responsible for differences in protection against RSV compared to influenza have begun to be elucidated in the human context. Influenza infection elicits high-affinity IgA in the respiratory tract and virus-specific IgG, which correlates with protection. Long-lived influenza-specific T cells have also been shown to ameliorate disease. This robust immunity promotes rapid emergence of antigenic variants leading to immune escape. RSV differs markedly, as reinfection with similar strains occurs despite natural infection inducing high levels of antibody against conserved antigens. The immunomodulatory mechanisms of RSV are thus highly effective in inhibiting long-term protection, with disturbance of type I interferon signaling, antigen presentation and chemokine-induced inflammation possibly all contributing. These lead to widespread effects on adaptive immunity with impaired B cell memory and reduced T cell

Induction and Subversion of Human Protective Immunity: Contrasting Influenza and Respiratory Syncytial Virus

Science.gov (United States)

Ascough, Stephanie; Paterson, Suzanna; Chiu, Christopher

2018-01-01

Respiratory syncytial virus (RSV) and influenza are among the most important causes of severe respiratory disease worldwide. Despite the clinical need, barriers to developing reliably effective vaccines against these viruses have remained firmly in place for decades. Overcoming these hurdles requires better understanding of human immunity and the strategies by which these pathogens evade it. Although superficially similar, the virology and host response to RSV and influenza are strikingly distinct. Influenza induces robust strain-specific immunity following natural infection, although protection by current vaccines is short-lived. In contrast, even strain-specific protection is incomplete after RSV and there are currently no licensed RSV vaccines. Although animal models have been critical for developing a fundamental understanding of antiviral immunity, extrapolating to human disease has been problematic. It is only with recent translational advances (such as controlled human infection models and high-dimensional technologies) that the mechanisms responsible for differences in protection against RSV compared to influenza have begun to be elucidated in the human context. Influenza infection elicits high-affinity IgA in the respiratory tract and virus-specific IgG, which correlates with protection. Long-lived influenza-specific T cells have also been shown to ameliorate disease. This robust immunity promotes rapid emergence of antigenic variants leading to immune escape. RSV differs markedly, as reinfection with similar strains occurs despite natural infection inducing high levels of antibody against conserved antigens. The immunomodulatory mechanisms of RSV are thus highly effective in inhibiting long-term protection, with disturbance of type I interferon signaling, antigen presentation and chemokine-induced inflammation possibly all contributing. These lead to widespread effects on adaptive immunity with impaired B cell memory and reduced T cell generation and

Sterile protection against Plasmodium knowlesi in rhesus monkeys from a malaria vaccine: comparison of heterologous prime boost strategies.

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George Jiang

Full Text Available Using newer vaccine platforms which have been effective against malaria in rodent models, we tested five immunization regimens against Plasmodium knowlesi in rhesus monkeys. All vaccines included the same four P. knowlesi antigens: the pre-erythrocytic antigens CSP, SSP2, and erythrocytic antigens AMA1, MSP1. We used four vaccine platforms for prime or boost vaccinations: plasmids (DNA, alphavirus replicons (VRP, attenuated adenovirus serotype 5 (Ad, or attenuated poxvirus (Pox. These four platforms combined to produce five different prime/boost vaccine regimens: Pox alone, VRP/Pox, VRP/Ad, Ad/Pox, and DNA/Pox. Five rhesus monkeys were immunized with each regimen, and five Control monkeys received a mock vaccination. The time to complete vaccinations was 420 days. All monkeys were challenged twice with 100 P. knowlesi sporozoites given IV. The first challenge was given 12 days after the last vaccination, and the monkeys receiving the DNA/Pox vaccine were the best protected, with 3/5 monkeys sterilely protected and 1/5 monkeys that self-cured its parasitemia. There was no protection in monkeys that received Pox malaria vaccine alone without previous priming. The second sporozoite challenge was given 4 months after the first. All 4 monkeys that were protected in the first challenge developed malaria in the second challenge. DNA, VRP and Ad5 vaccines all primed monkeys for strong immune responses after the Pox boost. We discuss the high level but short duration of protection in this experiment and the possible benefits of the long interval between prime and boost.

Seasonal influenza split vaccines confer partial cross-protection against heterologous influenza virus in ferrets when combined with the CAF01 adjuvant

DEFF Research Database (Denmark)

Christensen, Dennis; Christensen, Jan P.; Korsholm, Karen S.

2018-01-01

Influenza epidemics occur annually, and estimated 5-10% of the adult population and 20-30% of children will become ill from influenza infection. Seasonal vaccines primarily work through the induction of neutralizing antibodies against the principal surface antigen hemagglutinin (HA). This important...... role of HA-specific antibodies explains why previous pandemics have emerged when new HAs have appeared in circulating human viruses. It has long been recognized that influenza virus-specific CD4(+) T cells are important in protection from infection through direct effector mechanisms or by providing...... help to B cells and CD8(+) T cells. However, the seasonal influenza vaccine is poor at inducing CD4(+) T-cell responses and needs to be combined with an adjuvant facilitating this response. In this study, we applied the ferret model to investigate the cross-protective efficacy of a heterologous...

A Plasmodium Promiscuous T Cell Epitope Delivered within the Ad5 Hexon Protein Enhances the Protective Efficacy of a Protein Based Malaria Vaccine.

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Jairo Andres Fonseca

Full Text Available A malaria vaccine is a public health priority. In order to produce an effective vaccine, a multistage approach targeting both the blood and the liver stage infection is desirable. The vaccine candidates also need to induce balanced immune responses including antibodies, CD4+ and CD8+ T cells. Protein-based subunit vaccines like RTS,S are able to induce strong antibody response but poor cellular reactivity. Adenoviral vectors have been effective inducing protective CD8+ T cell responses in several models including malaria; nonetheless this vaccine platform exhibits a limited induction of humoral immune responses. Two approaches have been used to improve the humoral immunogenicity of recombinant adenovirus vectors, the use of heterologous prime-boost regimens with recombinant proteins or the genetic modification of the hypervariable regions (HVR of the capsid protein hexon to express B cell epitopes of interest. In this study, we describe the development of capsid modified Ad5 vectors that express a promiscuous Plasmodium yoelii T helper epitope denominated PyT53 within the hexon HVR2 region. Several regimens were tested in mice to determine the relevance of the hexon modification in enhancing protective immune responses induced by the previously described protein-based multi-stage experimental vaccine PyCMP. A heterologous prime-boost immunization regime that combines a hexon modified vector with transgenic expression of PyCMP followed by protein immunizations resulted in the induction of robust antibody and cellular immune responses in comparison to a similar regimen that includes a vector with unmodified hexon. These differences in immunogenicity translated into a better protective efficacy against both the hepatic and red blood cell stages of P. yoelii. To our knowledge, this is the first time that a hexon modification is used to deliver a promiscuous T cell epitope. Our data support the use of such modification to enhance the immunogenicity

Heterologous human/rat HER2-specific exosome-targeted T cell vaccine stimulates potent humoral and CTL responses leading to enhanced circumvention of HER2 tolerance in double transgenic HLA-A2/HER2 mice.

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Xie, Yufeng; Wu, Jie; Xu, Aizhang; Ahmeqd, Shahid; Sami, Amer; Chibbar, Rajni; Freywald, Andrew; Zheng, Changyu; Xiang, Jim

2018-03-07

DNA vaccines composed of heterologous human HER2 and rat neu sequences induce stronger antibody response and protective antitumor immunity than either HER2 or neu DNA vaccines in transgenic mice. We previously developed HER2-specific exosome-targeted T-cell vaccine HER2-T EXO capable of stimulating HER2-specific CD8 + T-cell responses, but only leading to partial protective immunity in double-transgenic HLA-A2/HER2 mice with self-immune tolerance to HER2. Here, we constructed an adenoviral vector AdV HuRt expressing HuRt fusion protein composed of NH 2 -HER2 1-407 (Hu) and COOH-neu 408-690 (Rt) fragments, and developed a heterologous human/rat HER2-specific exosome-targeted T-cell vaccine HuRt-T EXO using polyclonal CD4 + T-cells uptaking exosomes released by AdV HuRt -transfected dendritic cells. We found that the HuRt-T EXO vaccine stimulates enhanced CD4 + T-cell responses leading to increased induction of HER2-specific antibody (∼70 µg/ml) compared to that (∼40 µg/ml) triggered by the homologous HER2-T EXO vaccine. By using PE-H-2K d /HER2 23-71 tetramer, we determined that HuRt-T EXO stimulates stronger HER2-specific CD8 + T-cell responses eradicating 90% of HER2-specific target cells, while HER2-T EXO -induced CD8 + T-cell responses only eliminating 53% targets. Furthermore, HuRt-T EXO , but not HER2-T EXO vaccination, is capable of suppressing early stage-established HER2-expressing 4T1 HER2 breast cancer in its lung metastasis or subcutaneous form in BALB/c mice, and of completely protecting transgenic HLA-A2/HER2 mice from growth of HLA-A2/HER2-expressing BL6-10 A2/HER2 melanoma. HuRt-T EXO -stimulated HER2-specific CD8 + T-cells not only are cytolytic to trastuzumab-resistant HLA-A2/HER2-expressing BT474/A2 breast tumor cells in vitro but also eradicates pre-established BT474/A2 tumors in athymic nude mice. Therefore, our novel heterologous human/rat HER2-specific T-cell vaccine HuRt-T EXO, circumventing HER2 tolerance, may provide a new

Immune Protection against Lethal Fungal-Bacterial Intra-Abdominal Infections

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Lilly, Elizabeth A.; Ikeh, Melanie; Nash, Evelyn E.; Fidel, Paul L.

2018-01-01

ABSTRACT Polymicrobial intra-abdominal infections (IAIs) are clinically prevalent and cause significant morbidity and mortality, especially those involving fungi. Our laboratory developed a mouse model of IAI and demonstrated that intraperitoneal inoculation with Candida albicans or other virulent non-albicans Candida (NAC) species plus Staphylococcus aureus resulted in 70 to 80% mortality in 48 to 72 h due to robust local and systemic inflammation (sepsis). Surprisingly, inoculation with Candida dubliniensis or Candida glabrata with S. aureus resulted in minimal mortality, and rechallenge of these mice with lethal C. albicans/S. aureus (i.e., coninfection) resulted in >90% protection. The purpose of this study was to define requirements for C. dubliniensis/S. aureus-mediated protection and interrogate the mechanism of the protective response. Protection was conferred by C. dubliniensis alone or by killed C. dubliniensis plus live S. aureus. S. aureus alone was not protective, and killed S. aureus compromised C. dubliniensis-induced protection. C. dubliniensis/S. aureus also protected against lethal challenge by NAC plus S. aureus and could protect for a long-term duration (60 days between primary challenge and C. albicans/S. aureus rechallenge). Unexpectedly, mice deficient in T and B cells (Rag-1 knockouts [KO]) survived both the initial C. dubliniensis/S. aureus challenge and the C. albicans/S. aureus rechallenge, indicating that adaptive immunity did not play a role. Similarly, mice depleted of macrophages prior to rechallenge were also protected. In contrast, protection was associated with high numbers of Gr-1hi polymorphonuclear leukocytes (PMNLs) in peritoneal lavage fluid within 4 h of rechallenge, and in vivo depletion of Gr-1+ cells prior to rechallenge abrogated protection. These results suggest that Candida species can induce protection against a lethal C. albicans/S. aureus IAI that is mediated by PMNLs and postulated to be a unique form of

Immune Protection against Lethal Fungal-Bacterial Intra-Abdominal Infections

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Elizabeth A. Lilly

2018-01-01

Full Text Available Polymicrobial intra-abdominal infections (IAIs are clinically prevalent and cause significant morbidity and mortality, especially those involving fungi. Our laboratory developed a mouse model of IAI and demonstrated that intraperitoneal inoculation with Candida albicans or other virulent non-albicans Candida (NAC species plus Staphylococcus aureus resulted in 70 to 80% mortality in 48 to 72 h due to robust local and systemic inflammation (sepsis. Surprisingly, inoculation with Candida dubliniensis or Candida glabrata with S. aureus resulted in minimal mortality, and rechallenge of these mice with lethal C. albicans/S. aureus (i.e., coninfection resulted in >90% protection. The purpose of this study was to define requirements for C. dubliniensis/S. aureus-mediated protection and interrogate the mechanism of the protective response. Protection was conferred by C. dubliniensis alone or by killed C. dubliniensis plus live S. aureus. S. aureus alone was not protective, and killed S. aureus compromised C. dubliniensis-induced protection. C. dubliniensis/S. aureus also protected against lethal challenge by NAC plus S. aureus and could protect for a long-term duration (60 days between primary challenge and C. albicans/S. aureus rechallenge. Unexpectedly, mice deficient in T and B cells (Rag-1 knockouts [KO] survived both the initial C. dubliniensis/S. aureus challenge and the C. albicans/S. aureus rechallenge, indicating that adaptive immunity did not play a role. Similarly, mice depleted of macrophages prior to rechallenge were also protected. In contrast, protection was associated with high numbers of Gr-1hi polymorphonuclear leukocytes (PMNLs in peritoneal lavage fluid within 4 h of rechallenge, and in vivo depletion of Gr-1+ cells prior to rechallenge abrogated protection. These results suggest that Candida species can induce protection against a lethal C. albicans/S. aureus IAI that is mediated by PMNLs and postulated to be a unique form of

Outer membrane vesicles of Gallibacterium anatis induce protective immunity in egg-laying hens.

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Pors, Susanne E; Pedersen, Ida J; Skjerning, Ragnhild Bager; Thøfner, Ida C N; Persson, Gry; Bojesen, Anders M

2016-11-15

Gallibacterium anatis causes infections in the reproductive tract of egg-laying hens and induce increased mortality and decreased egg production. New prophylactic measures are needed in order to improve animal welfare and production efficiency. Bacterial outer membrane vesicles (OMVs) have previously shown promising results in protection against infections and we hypothesized that OMVs could serve as an immunogen to protect egg-laying hens against G. anatis. To investigate the immunogenic potential of G. anatis OMVs, two in vivo studies in egg-laying hens were made. The trials assessedthe degree of protection provided by immunization with G. anatis OMV against challenge and the IgY responses in serum after immunization and challenge, respectively. A total of 64 egg-laying hens were included in the trials. OMVs for immunization were produced and purified from a high-producing G. anatis ΔtolR mutant. Challenge was done with G. anatis 12656-12 and evaluated by scoring lesions and bacterial re-isolation rates from peritoneum. Finally, levels of OMV-specific IgY in sera were assayed by ELISA. Immunization with OMVs decreased the lesions scores significantly, while the bacterial re-isolation remained unchanged. Furthermore, a high OMV-specific IgY response was induced by immunization and subsequent challenge of the hens. The results strongly indicate that immunization with G. anatis OMVs provides significant protection against G. anatis challenge and induces specific antibody responses with high titers of OMV-specific IgY in serum. The results therefore show great promise for OMV based vaccines aiming at providing protecting against G. anatis in egg-laying hens. Copyright © 2016 Elsevier B.V. All rights reserved.

The serological response to heartwater immunization in cattle is an indicator of protective immunity

DEFF Research Database (Denmark)

Lawrence, J A; Tjørnehøj, Kirsten; Whiteland, A P

1995-01-01

A significant correlation was demonstrated in Friesian-cross steers between the serological response to previous vaccination with the Ball 3 strain of Cowdria ruminantium and the development of protective immunity against the Kalota isolate from Malawi. Of 10 animals which seroconverted after vac...

Heterologous Production of Cyanobacterial Mycosporine-Like Amino Acids Mycosporine-Ornithine and Mycosporine-Lysine in Escherichia coli

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Katoch, Meenu; Mazmouz, Rabia; Chau, Rocky; Pearson, Leanne A.; Pickford, Russell

2016-01-01

ABSTRACT Mycosporine-like amino acids (MAAs) are an important class of secondary metabolites known for their protection against UV radiation and other stress factors. Cyanobacteria produce a variety of MAAs, including shinorine, the active ingredient in many sunscreen creams. Bioinformatic analysis of the genome of the soil-dwelling cyanobacterium Cylindrospermum stagnale PCC 7417 revealed a new gene cluster with homology to MAA synthase from Nostoc punctiforme. This newly identified gene cluster is unusual because it has five biosynthesis genes (mylA to mylE), compared to the four found in other MAA gene clusters. Heterologous expression of mylA to mylE in Escherichia coli resulted in the production of mycosporine-lysine and the novel compound mycosporine-ornithine. To our knowledge, this is the first time these compounds have been heterologously produced in E. coli and structurally characterized via direct spectral guidance. This study offers insight into the diversity, biosynthesis, and structure of cyanobacterial MAAs and highlights their amenability to heterologous production methods. IMPORTANCE Mycosporine-like amino acids (MAAs) are significant from an environmental microbiological perspective as they offer microbes protection against a variety of stress factors, including UV radiation. The heterologous expression of MAAs in E. coli is also significant from a biotechnological perspective as MAAs are the active ingredient in next-generation sunscreens. PMID:27520810

Insights into the mechanisms of protective immunity against Cryptococcus neoformans infection using a mouse model of pulmonary cryptococcosis.

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Karen L Wozniak

2009-09-01

Full Text Available Cryptococcus neoformans is an opportunistic fungal pathogen that causes life-threatening pneumonia and meningoencephalitis in immune compromised individuals. Previous studies have shown that immunization of BALB/c mice with an IFN-gamma-producing C. neoformans strain, H99gamma, results in complete protection against a second pulmonary challenge with an otherwise lethal cryptococcal strain. The current study evaluated local anamnestic cell-mediated immune responses against pulmonary cryptococcosis in mice immunized with C. neoformans strain H99gamma compared to mice immunized with heat-killed C. neoformans (HKC.n.. Mice immunized with C. neoformans strain H99gamma had significantly reduced pulmonary fungal burden post-secondary challenge compared to mice immunized with HKC.n. Protection against pulmonary cryptococcosis was associated with increased pulmonary granulomatous formation and leukocyte infiltration followed by a rapid resolution of pulmonary inflammation, which protected the lungs from severe allergic bronchopulmonary mycosis (ABPM-pathology that developed in the lungs of mice immunized with HKC.n. Pulmonary challenge of interleukin (IL-4 receptor, IL-12p40, IL-12p35, IFN-gamma, T cell and B cell deficient mice with C. neoformans strain H99gamma demonstrated a requirement for Th1-type T cell-mediated immunity, but not B cell-mediated immunity, for the induction of H99gamma-mediated protective immune responses against pulmonary C. neoformans infection. CD4(+ T cells, CD11c(+ cells, and Gr-1(+ cells were increased in both proportion and absolute number in protected mice. In addition, significantly increased production of Th1-type/pro-inflammatory cytokines and chemokines, and conversely, reduced Th2-type cytokine production was observed in the lungs of protected mice. Interestingly, protection was not associated with increased production of cytokines IFN-gamma or TNF-alpha in lungs of protected mice. In conclusion, immunization with C

Strain- and Dose-Dependent Reduction of Toxoplasma gondii Burden in Pigs Is Associated with Interferon-Gamma Production by CD8+ Lymphocytes in a Heterologous Challenge Model

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Malgorzata Jennes

2017-06-01

Full Text Available Toxoplasma gondii is a worldwide prevalent parasite of humans and animals. The global infection burden exceeds yearly one million disability-adjusted life years (DALY's in infected individuals. Therefore, effective preventive measures should be taken to decrease the risk of infection in humans. Although human toxoplasmosis is predominantly foodborne by ingestion of tissue cysts in meat from domestic animals such as pigs, the incidence risk is difficult to estimate due to the lack of screening of animals for infection and insights in location and persistence of the parasite in the tissues. Hence, experimental infections in pigs can provide more information on the risk for zoonosis based on the parasite burden in meat products intended for human consumption and on the immune responses induced by infection. In the present study, homo- and heterologous infection experiments with two distinct T. gondii strains (IPB-LR and IPB-Gangji were performed. The humoral and cellular immune responses, the presence of viable parasites and the parasite load in edible meat samples were evaluated. In homologous infection experiments the parasite persistence was clearly strain-dependent and inversely correlated with the infection dose. The results strongly indicate a change in the amount of parasite DNA and viable cysts in porcine tissues over time. Heterologous challenge infections demonstrated that IPB-G strain could considerably reduce the parasite burden in the subsequent IPB-LR infection. A strong, however, not protective humoral response was observed against GRA7 and TLA antigens upon inoculation with both strains. The in vitro IFN-γ production by TLA-stimulated PBMCs was correlated with the infection dose and predominantly brought about by CD3+CD4−CD8αbright T-lymphocytes. The described adaptive cellular and humoral immune responses in pigs are in line with the induced or natural infections in mice and humans. Previous studies underscored the

Optimization of heterologous DNA-prime, protein boost regimens and site of vaccination to enhance therapeutic immunity against human papillomavirus-associated disease.

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Peng, Shiwen; Qiu, Jin; Yang, Andrew; Yang, Benjamin; Jeang, Jessica; Wang, Joshua W; Chang, Yung-Nien; Brayton, Cory; Roden, Richard B S; Hung, Chien-Fu; Wu, T-C

2016-01-01

Human papillomavirus (HPV) has been identified as the primary etiologic factor of cervical cancer as well as subsets of anogenital and oropharyngeal cancers. The two HPV viral oncoproteins, E6 and E7, are uniquely and consistently expressed in all HPV infected cells and are therefore promising targets for therapeutic vaccination. Both recombinant naked DNA and protein-based HPV vaccines have been demonstrated to elicit HPV-specific CD8+ T cell responses that provide therapeutic effects against HPV-associated tumor models. Here we examine the immunogenicity in a preclinical model of priming with HPV DNA vaccine followed by boosting with filterable aggregates of HPV 16 L2E6E7 fusion protein (TA-CIN). We observed that priming twice with an HPV DNA vaccine followed by a single TA-CIN booster immunization generated the strongest antigen-specific CD8+ T cell response compared to other prime-boost combinations tested in C57BL/6 mice, whether naïve or bearing the HPV16 E6/E7 transformed syngeneic tumor model, TC-1. We showed that the magnitude of antigen-specific CD8+ T cell response generated by the DNA vaccine prime, TA-CIN protein vaccine boost combinatorial strategy is dependent on the dose of TA-CIN protein vaccine. In addition, we found that a single booster immunization comprising intradermal or intramuscular administration of TA-CIN after priming twice with an HPV DNA vaccine generated a comparable boost to E7-specific CD8+ T cell responses. We also demonstrated that the immune responses elicited by the DNA vaccine prime, TA-CIN protein vaccine boost strategy translate into potent prophylactic and therapeutic antitumor effects. Finally, as seen for repeat TA-CIN protein vaccination, we showed that the heterologous DNA prime and protein boost vaccination strategy is well tolerated by mice. Our results provide rationale for future clinical testing of HPV DNA vaccine prime, TA-CIN protein vaccine boost immunization regimen for the control of HPV-associated diseases.

Anterior Chamber-Associated Immune Deviation (ACAID: An Acute Response to Ocular Insult Protects from Future Immune-Mediated Damage?

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Robert E. Cone

2009-01-01

Full Text Available The “immune privilege” that inhibits immune defense mechanisms that could lead to damage to sensitive ocular tissue is based on the expression of immunosuppressive factors on ocular tissue and in ocular fluids. In addition to this environmental protection, the injection of antigen into the anterior chamber or infection in the anterior chamber induces a systemic suppression of potentially damaging cell-mediated and humoral responses to the antigen. Here we discuss evidence that suggests that Anterior Chamber-Associated Immune Deviation (ACAID a is initiated by an ocular response to moderate inflammation that leads to a systemic immunoregulatory response. Injection into the anterior chamber induces a rise in TNF-α and MCP-1 in aqueous humor and an infiltration of circulating F4/80 + monocytes that home to the iris. The induction of ACAID is dependent on this infiltration of circulating monocytes that eventually emigrate to the thymus and spleen where they induce regulatory T cells that inhibit the inductive or effector phases of a cell-mediated immune response. ACAID therefore protects the eye from the collateral damage of an immune response to infection by suppressing a future potentially damaging response to infection.

Method for determining heterologous biosynthesis pathways

KAUST Repository

Gao, Xin

2017-08-10

The present invention relates to a method and system for dynamically analyzing, determining, predicting and displaying ranked suitable heterologous biosynthesis pathways for a specified host. The present invention addresses the problem of finding suitable pathways for the endogenous metabolism of a host organism because the efficacy of heterologous biosynthesis is affected by competing endogenous pathways. The present invention is called MRE (Metabolic Route Explorer), and it was conceived and developed to systematically and dynamically search for, determine, analyze, and display promising heterologous pathways while considering competing endogenous reactions in a given host organism.

Local Th17/IgA immunity correlate with protection against intranasal infection with Streptococcus pyogenes.

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Rasmus Mortensen

Full Text Available Streptococcus pyogenes (group A streptococcus, GAS is responsible for a wide array of infections. Respiratory transmission via droplets is the most common mode of transmission but it may also infect the host via other routes such as lesions in the skin. To advance the development of a future vaccine against GAS, it is therefore important to investigate how protective immunity is related to the route of vaccine administration. To explore this, we examined whether a parenterally administered anti-GAS vaccine could protect against an intranasal GAS infection or if this would require locally primed immunity. We foundd that a parenteral CAF01 adjuvanted GAS vaccine offered no protection against intranasal infection despite inducing strong systemic Th1/Th17/IgG immunity that efficiently protected against an intraperitoneal GAS infection. However, the same vaccine administered via the intranasal route was able to induce protection against repeated intranasal GAS infections in a murine challenge model. The lack of intranasal protection induced by the parenteral vaccine correlated with a reduced mucosal recall response at the site of infection. Taken together, our results demonstrate that locally primed immunity is important for the defense against intranasal infection with Streptococcus pyogenes.

Immune correlates of protection for dengue: State of the art and research agenda.

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Katzelnick, Leah C; Harris, Eva

2017-08-24

Dengue viruses (DENV1-4) are mosquito-borne flaviviruses estimated to cause up to ∼400 million infections and ∼100 million dengue cases each year. Factors that contribute to protection from and risk of dengue and severe dengue disease have been studied extensively but are still not fully understood. Results from Phase 3 vaccine efficacy trials have recently become available for one vaccine candidate, now licensed for use in several countries, and more Phase 2 and 3 studies of additional vaccine candidates are ongoing, making these issues all the more urgent and timely. At the "Summit on Dengue Immune Correlates of Protection", held in Annecy, France, on March 8-9, 2016, dengue experts from diverse fields came together to discuss the current understanding of the immune response to and protection from DENV infection and disease, identify key unanswered questions, discuss data on immune correlates and plans for comparison of results across assays/consortia, and propose a research agenda for investigation of dengue immune correlates, all in the context of both natural infection studies and vaccine trials. Copyright © 2017.

The HyVac4 subunit vaccine efficiently boosts BCG-primed anti-mycobacterial protective immunity.

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Rolf Billeskov

Full Text Available BACKGROUND: The current vaccine against tuberculosis (TB, BCG, has failed to control TB worldwide and the protective efficacy is moreover limited to 10-15 years. A vaccine that could efficiently boost a BCG-induced immune response and thus prolong protective immunity would therefore have a significant impact on the global TB-burden. METHODS/FINDINGS: In the present study we show that the fusion protein HyVac4 (H4, consisting of the mycobacterial antigens Ag85B and TB10.4, given in the adjuvant IC31® or DDA/MPL effectively boosted and prolonged immunity induced by BCG, leading to improved protection against infection with virulent M. tuberculosis (M.tb. Increased protection correlated with an increased percentage of TB10.4 specific IFNγ/TNFα/IL-2 or TNFα/IL-2 producing CD4 T cells at the site of infection. Moreover, this vaccine strategy did not compromise the use of ESAT-6 as an accurate correlate of disease development/vaccine efficacy. Indeed both CD4 and CD8 ESAT-6 specific T cells showed significant correlation with bacterial levels. CONCLUSIONS/SIGNIFICANCE: H4-IC31® can efficiently boost BCG-primed immunity leading to an increased protective anti-M.tb immune response dominated by IFNγ/TNFα/IL-2 or TNFα/IL2 producing CD4 T cells. H4 in the CD4 T cell inducing adjuvant IC31® is presently in clinical trials.

Immunization of baboons with attenuated schistosomula of Schistosoma haematobium: levels of protection induced by immunization with larvae irradiated with 20 and 60 krad

International Nuclear Information System (INIS)

Harrison, R.A.; Bickle, Q.D.; Sturrock, R.F.; Taylor, M.G.; Webbe, G.; Kiare, S.; James, E.R.; Andrews, B.J.

1990-01-01

The authors have demonstrated that baboons can be immunized with S. haemotobium schistosomula irradiated with 20 krad in a regimen that induces 90% protection. While this high level of protection has stimulated a discussion on the feasibility of a human volunteer trial (Von Lichtenberg, 1985), results of further studies particularly on (i) the pathogensis of immunization per se (Byram et al., 1989), (ii) the longevity of protection, and (iii) the protective efficacy of cryopreserved irradiated S. haemotobium schistosomula (R. Harrison et al., in preparation), prevent recommending this form of vaccination for human application. (author)

Immunization with cholera toxin B subunit induces high-level protection in the suckling mouse model of cholera.

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Gregory A Price

Full Text Available Cholera toxin (CT is the primary virulence factor responsible for severe cholera. Vibrio cholerae strains unable to produce CT show severe attenuation of virulence in animals and humans. The pentameric B subunit of CT (CTB contains the immunodominant epitopes recognized by antibodies that neutralize CT. Although CTB is a potent immunogen and a promising protective vaccine antigen in animal models, immunization of humans with detoxified CT failed to protect against cholera. We recently demonstrated however that pups reared from mice immunized intraperitoneally (IP with 3 doses of recombinant CTB were well protected against a highly lethal challenge dose of V. cholerae N16961. The present study investigated how the route and number of immunizations with CTB could influence protective efficacy in the suckling mouse model of cholera. To this end female mice were immunized with CTB intranasally (IN, IP, and subcutaneously (SC. Serum and fecal extracts were analyzed for anti-CTB antibodies by quantitative ELISA, and pups born to immunized mothers were challenged orogastrically with a lethal dose of V. cholerae. Pups from all immunized groups were highly protected from death by 48 hours (64-100% survival. Cox regression showed that percent body weight loss at 24 hours predicted death by 48 hours, but we were unable to validate a specific amount of weight loss as a surrogate marker for protection. Although CTB was highly protective in all regimens, three parenteral immunizations showed trends toward higher survival and less weight loss at 24 hours post infection. These results demonstrate that immunization with CTB by any of several routes and dosing regimens can provide protection against live V. cholerae challenge in the suckling mouse model of cholera. Our data extend the results of previous studies and provide additional support for the inclusion of CTB in the development of a subunit vaccine against V. cholerae.

Photosynthetic fuel for heterologous enzymes

DEFF Research Database (Denmark)

Mellor, Silas Busck; Vavitsas, Konstantinos; Nielsen, Agnieszka Janina Zygadlo

2017-01-01

of reducing power. Recent work on the metabolic engineering of photosynthetic organisms has shown that the electron carriers such as ferredoxin and flavodoxin can be used to couple heterologous enzymes to photosynthetic reducing power. Because these proteins have a plethora of interaction partners and rely...... on electrostatically steered complex formation, they form productive electron transfer complexes with non-native enzymes. A handful of examples demonstrate channeling of photosynthetic electrons to drive the activity of heterologous enzymes, and these focus mainly on hydrogenases and cytochrome P450s. However......, competition from native pathways and inefficient electron transfer rates present major obstacles, which limit the productivity of heterologous reactions coupled to photosynthesis. We discuss specific approaches to address these bottlenecks and ensure high productivity of such enzymes in a photosynthetic...

Structural basis for the development of avian virus capsids that display influenza virus proteins and induce protective immunity.

Science.gov (United States)

Pascual, Elena; Mata, Carlos P; Gómez-Blanco, Josué; Moreno, Noelia; Bárcena, Juan; Blanco, Esther; Rodríguez-Frandsen, Ariel; Nieto, Amelia; Carrascosa, José L; Castón, José R

2015-03-01

Bioengineering of viruses and virus-like particles (VLPs) is a well-established approach in the development of new and improved vaccines against viral and bacterial pathogens. We report here that the capsid of a major avian pathogen, infectious bursal disease virus (IBDV), can accommodate heterologous proteins to induce protective immunity. The structural units of the ~70-nm-diameter T=13 IBDV capsid are trimers of VP2, which is made as a precursor (pVP2). The pVP2 C-terminal domain has an amphipathic α helix that controls VP2 polymorphism. In the absence of the VP3 scaffolding protein, 466-residue pVP2 intermediates bearing this α helix assemble into genuine VLPs only when expressed with an N-terminal His6 tag (the HT-VP2-466 protein). HT-VP2-466 capsids are optimal for protein insertion, as they are large enough (cargo space, ~78,000 nm(3)) and are assembled from a single protein. We explored HT-VP2-466-based chimeric capsids initially using enhanced green fluorescent protein (EGFP). The VLP assembly yield was efficient when we coexpressed EGFP-HT-VP2-466 and HT-VP2-466 from two recombinant baculoviruses. The native EGFP structure (~240 copies/virion) was successfully inserted in a functional form, as VLPs were fluorescent, and three-dimensional cryo-electron microscopy showed that the EGFP molecules incorporated at the inner capsid surface. Immunization of mice with purified EGFP-VLPs elicited anti-EGFP antibodies. We also inserted hemagglutinin (HA) and matrix (M2) protein epitopes derived from the mouse-adapted A/PR/8/34 influenza virus and engineered several HA- and M2-derived chimeric capsids. Mice immunized with VLPs containing the HA stalk, an M2 fragment, or both antigens developed full protection against viral challenge. Virus-like particles (VLPs) are multimeric protein cages that mimic the infectious virus capsid and are potential candidates as nonliving vaccines that induce long-lasting protection. Chimeric VLPs can display or include foreign

Multiserotype protection elicited by a combinatorial prime-boost vaccination strategy against bluetongue virus.

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Eva Calvo-Pinilla

Full Text Available Bluetongue virus (BTV belongs to the genus Orbivirus within the family Reoviridae. The development of vector-based vaccines expressing conserved protective antigens results in increased immune activation and could reduce the number of multiserotype vaccinations required, therefore providing a cost-effective product. Recent recombinant DNA technology has allowed the development of novel strategies to develop marker and safe vaccines against BTV. We have now engineered naked DNAs and recombinant modified vaccinia virus Ankara (rMVA expressing VP2, VP7 and NS1 proteins from BTV-4. IFNAR((-/- mice inoculated with DNA/rMVA-VP2,-VP7-NS1 in an heterologous prime boost vaccination strategy generated significant levels of antibodies specific of VP2, VP7, and NS1, including those with neutralizing activity against BTV-4. In addition, vaccination stimulated specific CD8(+ T cell responses against these three BTV proteins. Importantly, the vaccine combination expressing NS1, VP2 and VP7 proteins of BTV-4, elicited sterile protection against a lethal dose of homologous BTV-4 infection. Remarkably, the vaccine induced cross-protection against lethal doses of heterologous BTV-8 and BTV-1 suggesting that the DNA/rMVA-VP2,-VP7,-NS1 marker vaccine is a promising multiserotype vaccine against BTV.

Multiple linear B-cell epitopes of classical swine fever virus glycoprotein E2 expressed in E.coli as multiple epitope vaccine induces a protective immune response

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Wei Jian-Chao

2011-07-01

Full Text Available Abstract Classical swine fever is a highly contagious disease of swine caused by classical swine fever virus, an OIE list A pathogen. Epitope-based vaccines is one of the current focuses in the development of new vaccines against classical swine fever virus (CSFV. Two B-cell linear epitopes rE2-ba from the E2 glycoprotein of CSFV, rE2-a (CFRREKPFPHRMDCVTTTVENED, aa844-865 and rE2-b (CKEDYRYAISSTNEIGLLGAGGLT, aa693-716, were constructed and heterologously expressed in Escherichia coli as multiple epitope vaccine. Fifteen 6-week-old specified-pathogen-free (SPF piglets were intramuscularly immunized with epitopes twice at 2-week intervals. All epitope-vaccinated pigs could mount an anamnestic response after booster vaccination with neutralizing antibody titers ranging from 1:16 to 1:256. At this time, the pigs were subjected to challenge infection with a dose of 1 × 106 TCID50 virulent CSFV strain. After challenge infection, all of the rE2-ba-immunized pigs were alive and without symptoms or signs of CSF. In contrast, the control pigs continuously exhibited signs of CSF and had to be euthanized because of severe clinical symptoms at 5 days post challenge infection. The data from in vivo experiments shown that the multiple epitope rE2-ba shown a greater protection (similar to that of HCLV vaccine than that of mono-epitope peptide(rE2-a or rE2-b. Therefore, The results demonstrated that this multiple epitope peptide expressed in a prokaryotic system can be used as a potential DIVA (differentiating infected from vaccinated animals vaccine. The E.coli-expressed E2 multiple B-cell linear epitopes retains correct immunogenicity and is able to induce a protective immune response against CSFV infection.

Transfer of maternal immunity to piglets is involved in early protection against Mycoplasma hyosynoviae infection

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Lauritsen, Klara Tølbøl; Hagedorn-Olsen, Tine; Jungersen, Gregers

2017-01-01

Mycoplasma hyosynoviae causes arthritis in pigs older than 12 weeks. The role of colostrum in protection of piglets against M. hyosynoviae infection is not clear. Our objective was therefore to investigate whether transfer of maternal immunity to piglets was involved in early protection against...... immune response that complements the maternally transferred immune factors. Evident from this study is that the general absence of M. hyosynoviae arthritis in piglets can be ascribed mainly to their immunological status....

Cross-serotype immunity induced by immunization with a conserved rhinovirus capsid protein.

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Nicholas Glanville

Full Text Available Human rhinovirus (RV infections are the principle cause of common colds and precipitate asthma and COPD exacerbations. There is currently no RV vaccine, largely due to the existence of ∼150 strains. We aimed to define highly conserved areas of the RV proteome and test their usefulness as candidate antigens for a broadly cross-reactive vaccine, using a mouse infection model. Regions of the VP0 (VP4+VP2 capsid protein were identified as having high homology across RVs. Immunization with a recombinant VP0 combined with a Th1 promoting adjuvant induced systemic, antigen specific, cross-serotype, cellular and humoral immune responses. Similar cross-reactive responses were observed in the lungs of immunized mice after infection with heterologous RV strains. Immunization enhanced the generation of heterosubtypic neutralizing antibodies and lung memory T cells, and caused more rapid virus clearance. Conserved domains of the RV capsid therefore induce cross-reactive immune responses and represent candidates for a subunit RV vaccine.

Immunogenicity is unrelated to protective immunity when induced by soluble and particulate antigens from Nocardia brasiliensis in BALB/c mice.

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Salinas-Carmona, Mario C; Ramos, Alma I; Pérez-Rivera, Isabel

2006-08-01

Cell-mediated immunity plays a major role in protection against intracellular microbes. Nocardia brasiliensis is a facultative intracellular pathogen that causes chronic actinomycetoma. In this work, we injected BALB/c mice with soluble P24 and particulate antigens from N. brasiliensis. A higher antibody titer and lymphocyte proliferation was induced by the particulate antigen than by the soluble antigen. However, five months after antigen injection, antibody concentration and lymphocyte proliferation were similar. An increase in CD45R and CD4 T cells was unrelated to protective immunity. Active immunization with soluble or particulate antigens induced complete protection during the primary immune response. This protective response was IgM mediated. The higher immunogenicity was not related to protective immunity since the particulate antigen induced protection similar to the soluble antigen. Using particulate antigens for vaccination guarantees a stronger immune response, local and systemic side effects, but not necessarily protection.

Protective efficacy of Newcastle disease virus expressing soluble trimeric hemagglutinin against highly pathogenic H5N1 influenza in chickens and mice.

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Lisette A H M Cornelissen

Full Text Available BACKGROUND: Highly pathogenic avian influenza virus (HPAIV causes a highly contagious often fatal disease in poultry, resulting in significant economic losses in the poultry industry. HPAIV H5N1 also poses a major public health threat as it can be transmitted directly from infected poultry to humans. One effective way to combat avian influenza with pandemic potential is through the vaccination of poultry. Several live vaccines based on attenuated Newcastle disease virus (NDV that express influenza hemagglutinin (HA have been developed to protect chickens or mammalian species against HPAIV. However, the zoonotic potential of NDV raises safety concerns regarding the use of live NDV recombinants, as the incorporation of a heterologous attachment protein may result in the generation of NDV with altered tropism and/or pathogenicity. METHODOLOGY/PRINCIPAL FINDINGS: In the present study we generated recombinant NDVs expressing either full length, membrane-anchored HA of the H5 subtype (NDV-H5 or a soluble trimeric form thereof (NDV-sH5(3. A single intramuscular immunization with NDV-sH5(3 or NDV-H5 fully protected chickens against disease after a lethal challenge with H5N1 and reduced levels of virus shedding in tracheal and cloacal swabs. NDV-sH5(3 was less protective than NDV-H5 (50% vs 80% protection when administered via the respiratory tract. The NDV-sH5(3 was ineffective in mice, regardless of whether administered oculonasally or intramuscularly. In this species, NDV-H5 induced protective immunity against HPAIV H5N1, but only after oculonasal administration, despite the poor H5-specific serum antibody response it elicited. CONCLUSIONS/SIGNIFICANCE: Although NDV expressing membrane anchored H5 in general provided better protection than its counterpart expressing soluble H5, chickens could be fully protected against a lethal challenge with H5N1 by using the latter NDV vector. This study thus provides proof of concept for the use of recombinant

[Effect of immune modulation on immunogenic and protective activity of a live plague vaccine].

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Karal'nik, B V; Ponomareva, T S; Deriabin, P N; Denisova, T G; Mel'nikova, N N; Tugambaev, T I; Atshabar, B B; Zakarian, S B

2014-01-01

Comparative evaluation of the effect of polyoxidonium and betaleukin on immunogenic and protective activity of a live plague vaccine in model animal experiments. Plague vaccine EV, polyoxidonium, betaleukin, erythrocytic antigenic diagnosticum for determination of F1 antibodies and immune reagents for detection of lymphocytes with F1 receptors (LFR) in adhesive test developed by the authors were used. The experiments were carried out in 12 rabbits and 169 guinea pigs. Immune modulation accelerated the appearance and disappearance of LFR (early phase) and ensured a more rapid and intensive antibody formation (effector phase). Activation by betaleukin is more pronounced than by polyoxidonium. The more rapid and intensive was the development of early phase, the more effective was antibody response to the vaccine. Immune modulation in the experiment with guinea pigs significantly increased protective activity of the vaccine. The use of immune modulators increased immunogenic (in both early and effector phases of antigen-specific response) and protective activity of the EV vaccine. A connection between the acceleration of the first phase of antigen-specific response and general intensity of effector phase of immune response to the EV vaccine was detected. ,

Identification of immune correlates of protection in Shigella infection by application of machine learning.

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Arevalillo, Jorge M; Sztein, Marcelo B; Kotloff, Karen L; Levine, Myron M; Simon, Jakub K

2017-10-01

Immunologic correlates of protection are important in vaccine development because they give insight into mechanisms of protection, assist in the identification of promising vaccine candidates, and serve as endpoints in bridging clinical vaccine studies. Our goal is the development of a methodology to identify immunologic correlates of protection using the Shigella challenge as a model. The proposed methodology utilizes the Random Forests (RF) machine learning algorithm as well as Classification and Regression Trees (CART) to detect immune markers that predict protection, identify interactions between variables, and define optimal cutoffs. Logistic regression modeling is applied to estimate the probability of protection and the confidence interval (CI) for such a probability is computed by bootstrapping the logistic regression models. The results demonstrate that the combination of Classification and Regression Trees and Random Forests complements the standard logistic regression and uncovers subtle immune interactions. Specific levels of immunoglobulin IgG antibody in blood on the day of challenge predicted protection in 75% (95% CI 67-86). Of those subjects that did not have blood IgG at or above a defined threshold, 100% were protected if they had IgA antibody secreting cells above a defined threshold. Comparison with the results obtained by applying only logistic regression modeling with standard Akaike Information Criterion for model selection shows the usefulness of the proposed method. Given the complexity of the immune system, the use of machine learning methods may enhance traditional statistical approaches. When applied together, they offer a novel way to quantify important immune correlates of protection that may help the development of vaccines. Copyright © 2017 Elsevier Inc. All rights reserved.

Protective Immunity against Hepatitis C: Many Shades of Grey

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Mohamed S Abdel-Hakeem

2014-06-01

Full Text Available The majority of individuals who become acutely infected with hepatitis C virus (HCV develop chronic infection and suffer from progressive liver damage while approximately 25% are able to eliminate the virus spontaneously. Despite the recent introduction of new direct-acting antivirals (DAAs, there is still no vaccine for HCV. As a result, new infections and reinfections will remain a problem in developing countries and among high risk populations like injection drug users (IDUs who have limited access to treatment and who continue to be exposed to the virus. The outcome of acute HCV is determined by the interplay between the host genetics, the virus and the virus-specific immune response. Studies in humans and chimpanzees have demonstrated the essential role of HCV-specific CD4 and CD8 T cell responses in protection against viral persistence. Recent data suggest that antibody responses play a more important role than what was previously thought. Individuals who spontaneously resolve acute HCV infection develop long-lived memory T cells and are less likely to become persistently infected upon re-exposure. New studies examining high risk cohorts are identifying correlates of protection during real life exposures and reinfections. In this review, we discuss correlates of protective immunity during acute HCV and upon reexposure. We draw parallels between HCV and the current knowledge about protective memory in other models of chronic viral infections. Finally, we discuss some of the yet unresolved questions about key correlates of protection and their relevance for vaccine development against HCV.

Prolonged protection against Intranasal challenge with influenza virus following systemic immunization or combinations of mucosal and systemic immunizations with a heat-labile toxin mutant.

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Zhou, Fengmin; Goodsell, Amanda; Uematsu, Yasushi; Vajdy, Michael

2009-04-01

Seasonal influenza virus infections cause considerable morbidity and mortality in the world, and there is a serious threat of a pandemic influenza with the potential to cause millions of deaths. Therefore, practical influenza vaccines and vaccination strategies that can confer protection against intranasal infection with influenza viruses are needed. In this study, we demonstrate that using LTK63, a nontoxic mutant of the heat-labile toxin from Escherichia coli, as an adjuvant for both mucosal and systemic immunizations, systemic (intramuscular) immunization or combinations of mucosal (intranasal) and intramuscular immunizations protected mice against intranasal challenge with a lethal dose of live influenza virus at 3.5 months after the second immunization.

Stimulation of TLR7 with Gardiquimod Enhances Protection and Activation of Immune Cells from γ-Irradiation Exposure

International Nuclear Information System (INIS)

Yang, Young-Mi; Bang, Ji-Young; Lee, Suhl-Hyeong; Moon, Tae-Min; Jung, Yu-Jin

2007-01-01

Radiotherapy for cancer patients is based on the radiation-induced cell death, but high dose of radiation is able to cause break of immune system. Thus, protection of immune cells from radiation damage is required to enhance the efficiency and reduce the harmful side effects during cancer radiotherapy. Toll-like receptors (TLRs) are important not only in initiating innate immunity against microbial infection, but also inducing Th1-mediated immunity with producing cytokines and chemokines. Cell stimulation via TLRs leads to downstream activation of NF-kB and other transcription factors. Consequently, several genes encoding mediators and effector molecules of the innate as well as the adaptive immune response are transcribed. There are several previous findings that activated immune cells via TLR9 inducing pathways are resistant to chemical or radiation exposure. But it is not clear that the other TLRs also have the same abilities to protect immune cells against cellular damages including γ-irradiation. This research was performed to evaluate protective effect of immune cells from γ-irradiation through TLR-7 activation pathway

Local Th17/IgA immunity correlate with protection against intranasal infection with Streptococcus pyogenes

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Mortensen, Rasmus; Christensen, Dennis; Hansen, Lasse Bøllehuus

2017-01-01

Streptococcus pyogenes (group A streptococcus, GAS) is responsible for a wide array of infections. Respiratory transmission via droplets is the most common mode of transmission but it may also infect the host via other routes such as lesions in the skin. To advance the development of a future...... vaccine against GAS, it is therefore important to investigate how protective immunity is related to the route of vaccine administration. To explore this, we examined whether a parenterally administered anti-GAS vaccine could protect against an intranasal GAS infection or if this would require locally...... primed immunity. We foundd that a parenteral CAF01 adjuvanted GAS vaccine offered no protection against intranasal infection despite inducing strong systemic Th1/Th17/IgG immunity that efficiently protected against an intraperitoneal GAS infection. However, the same vaccine administered via...

Protection of Broiler Chicks Housed with Immunized Cohorts Against Infection with Eimeria maxima and E. acervulina.

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Fetterer, Raymond H; Barfield, Ruth C; Jenkins, Mark C

2015-03-01

The use of live oocyst vaccines is becoming increasingly important in the control of avian coccidiosis in broilers. Knowledge of the mechanisms employed when chicks uptake oocysts and become immune is important for optimizing delivery of live vaccines. The current study tests the hypothesis that chicks not initially immunized may ingest oocysts by contact with litter containing oocysts shed by immunized cohorts. In Experiment 1, day-old broiler chicks were housed in pens containing clean litter. In Trial 1, 100% of chicks in some pens were immunized with 2.5 X 10(3) Eimeria acervulina oocysts while in other pens only 75% of chicks were immunized and remaining cohorts within the pens were not immunized. Other pens contained chicks that served as nonimmunized nonchallenged controls or nonimmunized challenged controls (NIC). On day 21, birds were given a homologous challenge of 6 X 10(5) oocysts. A second identical trial was conducted, except birds were immunized with 500 Eimeria maxima oocysts and were challenged with 3 X 10(3) E. maxima oocysts. In Experiment 2, 100% of chicks in some pens were immunized with 500 E. acervulina oocysts while in other pens either 75% or 50% of the birds were immunized. On day 14, birds were challenged with 1 X 10(6) oocysts. Trial 2 was identical to Trial 1 except that birds were immunized with 100 E. maxima oocysts and challenged with 1 X 10(6) oocysts. For all experiments weight gain, feed conversion ratio (FCR), plasma carotenoids, and litter oocyst counts were measured. In Experiment 1, the level of protection in groups containing 25% nonimmunized cohorts, as measured by weight gain, carotenoid level, FCR, and oocyst litter counts, was identical to groups containing 100% immunized chicks. In Experiment 2, pens where 50% or 75% of birds were immunized with either E. maxima or E. acervulina were not well protected from decreases in weight gain and plasma carotenoids nor from increases in litter oocyst counts following a challenge

Interferon-γ, a valuable surrogate marker of Plasmodium falciparum pre-erythrocytic stages protective immunity

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BenMohamed Lbachir

2011-02-01

Full Text Available Abstract Immunity against the pre-erythrocytic stages of malaria is the most promising, as it is strong and fully sterilizing. Yet, the underlying immune effectors against the human Plasmodium falciparum pre-erythrocytic stages remain surprisingly poorly known and have been little explored, which in turn prevents any rational vaccine progress. Evidence that has been gathered in vitro and in vivo, in higher primates and in humans, is reviewed here, emphasizing the significant role of IFN-γ, either as a critical immune mediator or at least as a valuable surrogate marker of protection. One may hope that these results will trigger investigations in volunteers immunized either by optimally irradiated or over-irradiated sporozoites, to quickly delineate better surrogates of protection, which are essential for the development of a successful malaria vaccine.

Induction of complex immune responses and strong protection against retrovirus challenge by adenovirus-based immunization depends on the order of vaccine delivery.

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Kaulfuß, Meike; Wensing, Ina; Windmann, Sonja; Hrycak, Camilla Patrizia; Bayer, Wibke

2017-02-06

In the Friend retrovirus mouse model we developed potent adenovirus-based vaccines that were designed to induce either strong Friend virus GagL 85-93 -specific CD8 + T cell or antibody responses, respectively. To optimize the immunization outcome we evaluated vaccination strategies using combinations of these vaccines. While the vaccines on their own confer strong protection from a subsequent Friend virus challenge, the simple combination of the vaccines for the establishment of an optimized immunization protocol did not result in a further improvement of vaccine effectivity. We demonstrate that the co-immunization with GagL 85-93 /leader-gag encoding vectors together with envelope-encoding vectors abrogates the induction of GagL 85-93 -specific CD8 + T cells, and in successive immunization protocols the immunization with the GagL 85-93 /leader-gag encoding vector had to precede the immunization with an envelope encoding vector for the efficient induction of GagL 85-93 -specific CD8 + T cells. Importantly, the antibody response to envelope was in fact enhanced when the mice were adenovirus-experienced from a prior immunization, highlighting the expedience of this approach. To circumvent the immunosuppressive effect of envelope on immune responses to simultaneously or subsequently administered immunogens, we developed a two immunizations-based vaccination protocol that induces strong immune responses and confers robust protection of highly Friend virus-susceptible mice from a lethal Friend virus challenge.

Social Immunity: Emergence and Evolution of Colony-Level Disease Protection.

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Cremer, Sylvia; Pull, Christopher D; Fürst, Matthias A

2018-01-07

Social insect colonies have evolved many collectively performed adaptations that reduce the impact of infectious disease and that are expected to maximize their fitness. This colony-level protection is termed social immunity, and it enhances the health and survival of the colony. In this review, we address how social immunity emerges from its mechanistic components to produce colony-level disease avoidance, resistance, and tolerance. To understand the evolutionary causes and consequences of social immunity, we highlight the need for studies that evaluate the effects of social immunity on colony fitness. We discuss the roles that host life history and ecology have on predicted eco-evolutionary dynamics, which differ among the social insect lineages. Throughout the review, we highlight current gaps in our knowledge and promising avenues for future research, which we hope will bring us closer to an integrated understanding of socio-eco-evo-immunology.

Exercise protects from cancer through regulation of immune function and inflammation

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Hojman, Pernille

2017-01-01

Exercise training has been extensively studied in cancer settings as part of prevention or rehabilitation strategies, yet emerging evidence suggests that exercise training can also directly affect tumor-specific outcomes. The underlying mechanisms for this exercise-dependent cancer protection are...... regulation of immune and inflammatory functions, and exercise may be pursued as anticancer treatment through incorporation into standard oncological therapy to the benefit of the cancer patients.......Exercise training has been extensively studied in cancer settings as part of prevention or rehabilitation strategies, yet emerging evidence suggests that exercise training can also directly affect tumor-specific outcomes. The underlying mechanisms for this exercise-dependent cancer protection...... are just starting to be elucidated. To this end, evasion of immune surveillance and tumor-associated inflammation are established as hallmarks of cancer, and exercise may target cancer incidence and progression through regulation of these mechanisms. Here, I review the role of exercise in protection from...

Lessons Learned from Protective Immune Responses to Optimize Vaccines against Cryptosporidiosis.

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Lemieux, Maxime W; Sonzogni-Desautels, Karine; Ndao, Momar

2017-12-24

In developing countries, cryptosporidiosis causes moderate-to-severe diarrhea and kills thousands of infants and toddlers annually. Drinking and recreational water contaminated with Cryptosporidium spp. oocysts has led to waterborne outbreaks in developed countries. A competent immune system is necessary to clear this parasitic infection. A better understanding of the immune responses required to prevent or limit infection by this protozoan parasite is the cornerstone of development of an effective vaccine. In this light, lessons learned from previously developed vaccines against Cryptosporidium spp. are at the foundation for development of better next-generation vaccines. In this review, we summarize the immune responses elicited by naturally and experimentally-induced Cryptosporidium spp. infection and by several experimental vaccines in various animal models. Our aim is to increase awareness about the immune responses that underlie protection against cryptosporidiosis and to encourage promotion of these immune responses as a key strategy for vaccine development. Innate and mucosal immunity will be addressed as well as adaptive immunity, with an emphasis on the balance between T H 1/T H 2 immune responses. Development of more effective vaccines against cryptosporidiosis is needed to prevent Cryptosporidium spp.-related deaths in infants and toddlers in developing countries.

Social immunity and the superorganism: Behavioral defenses protecting honey bee colonies from pathogens and parasites

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Honey bees (Apis mellifera) have a number of traits that effectively reduce the spread of pathogens and parasites throughout the colony. These mechanisms of social immunity are often analogous to the individual immune system. As such social immune defences function to protect the colony or superorga...

The Contribution of Cytomegalovirus Infection to Immune Senescence Is Set by the Infectious Dose

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Anke Redeker

2018-01-01

Full Text Available The relationship between human cytomegalovirus (HCMV infections and accelerated immune senescence is controversial. Whereas some studies reported a CMV-associated impaired capacity to control heterologous infections at old age, other studies could not confirm this. We hypothesized that these discrepancies might relate to the variability in the infectious dose of CMV occurring in real life. Here, we investigated the influence of persistent CMV infection on immune perturbations and specifically addressed the role of the infectious dose on the contribution of CMV to accelerated immune senescence. We show in experimental mouse models that the degree of mouse CMV (MCMV-specific memory CD8+ T cell accumulation and the phenotypic T cell profile are directly influenced by the infectious dose, and data on HCMV-specific T cells indicate a similar connection. Detailed cluster analysis of the memory CD8+ T cell development showed that high-dose infection causes a differentiation pathway that progresses faster throughout the life span of the host, suggesting a virus–host balance that is influenced by aging and infectious dose. Importantly, short-term MCMV infection in adult mice is not disadvantageous for heterologous superinfection with lymphocytic choriomeningitis virus (LCMV. However, following long-term CMV infection the strength of the CD8+ T cell immunity to LCMV superinfection was affected by the initial CMV infectious dose, wherein a high infectious dose was found to be a prerequisite for impaired heterologous immunity. Altogether our results underscore the importance of stratification based on the size and differentiation of the CMV-specific memory T cell pools for the impact on immune senescence, and indicate that reduction of the latent/lytic viral load can be beneficial to diminish CMV-associated immune senescence.

A protective effect of epidermal powder immunization in a mouse model of equine herpesvirus-1 infection

International Nuclear Information System (INIS)

Kondo, Takashi; McGregor, Martha; Chu, Qili; Chen, Dexiang; Horimoto, Taisuke; Kawaoka, Yoshihiro

2004-01-01

To evaluate the protective effect of epidermal powder immunization (EPI) against equine herpesvirus-1 (EHV-1) infection, we prepared a powder vaccine in which formalin-inactivated virions were embedded in water-soluble, sugar-based particles. A PowderJect device was used to immunize mice with the powder vaccine via their abdominal skin. We found that twice-immunized mice were protected against challenge with the wild-type virus. This protective effect was equivalent to or better than that observed in mice immunized with other types of vaccines, including a gene gun-mediated DNA vaccine containing the glycoprotein D (gD) gene or conventional inactivated virus vaccines introduced via intramuscular or intranasal injections. These findings indicate that the powder vaccine is a promising approach for the immunological control of EHV-1 infection, either alone or as a part of prime-boost vaccination strategies

Gamma-irradiated influenza A virus can prime for a cross-reactive and cross-protective immune response against influenza A viruses

International Nuclear Information System (INIS)

Mullbacher, A.; Ada, G.L.; Tha Hla, R.

1988-01-01

A-strain influenza virus A/JAP (H2N2) was tested for its ability to induce cytotoxic T cells (Tc) after being rendered non-infectious by either UV or gamma irradiation. Gamma-irradiated virus proved to be more efficient than UV-inactivated virus in priming for a memory Tc cell response or in boosting memory spleen cells in vitro. Most importantly, γ-inactivated, but not UV-inactivated, A/JAP immunized animals survived lethal challenge with heterologous (A/PC(H3N2), A/WSN(H1N1)) virus as effectively as mice primed with infectious virus

Intranasal immunization with protective antigen of Bacillus anthracis induces a long-term immunological memory response.

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Woo, Sun-Je; Kang, Seok-Seong; Park, Sung-Moo; Yang, Jae Seung; Song, Man Ki; Yun, Cheol-Heui; Han, Seung Hyun

2015-10-01

Although intranasal vaccination has been shown to be effective for the protection against inhalational anthrax, establishment of long-term immunity has yet to be achieved. Here, we investigated whether intranasal immunization with recombinant protective antigen (rPA) of Bacillus anthracis induces immunological memory responses in the mucosal and systemic compartments. Intranasal immunization with rPA plus cholera toxin (CT) sustained PA-specific antibody responses for 6 months in lung, nasal washes, and vaginal washes as well as serum. A significant induction of PA-specific memory B cells was observed in spleen, cervical lymph nodes (CLNs) and lung after booster immunization. Furthermore, intranasal immunization with rPA plus CT remarkably generated effector memory CD4(+) T cells in the lung. PA-specific CD4(+) T cells preferentially increased the expression of Th1- and Th17-type cytokines in lung, but not in spleen or CLNs. Collectively, the intranasal immunization with rPA plus CT promoted immunologic memory responses in the mucosal and systemic compartments, providing long-term immunity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Active immunizations with peptide-DC vaccines and passive transfer with antibodies protect neutropenic mice against disseminated candidiasis.

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Xin, Hong

2016-01-04

We previously report that peptide-pulsed dendritic cell (DC) vaccination, which targeting two peptides (Fba and Met6) expressed on the cell surface of Candida albicans, can induce high degree of protection against disseminated candidiasis in immunocompetent mice. Passive transfer of immune sera from the peptide immunized mice or peptide-related monoclonal antibodies demonstrated that protection was medicated by peptide-specific antibodies. In this study the efficacy of active and passive immunization against disseminated candidiasis was tested in mice with cyclophosphamide-induced neutropenia. Peptide-DC vaccines were given to mice prior to induction of neutropenia. We show active immunization with either Fba or Met6 peptide-DC vaccine significantly improved the survival and reduced the fungal burden of disseminated candidiasis in those immunocompromised mice. Importantly, we show that administration of two protective monoclonal antibodies also protect neutropenic mice against the disease, implying possibility of developing a successful passive immunotherapy strategy to treat the disease and protect against disseminated candidiasis. The results of this study are crucial as they address the fundamental questions as to whether the synthetic peptide vaccine induced immunity protects the host during a neutropenic episode. We anticipate that this peptide-vaccine study will serve as the foundation of future investigations into new peptide vaccines comprised of cell surface peptides from other medically important Candida species, as well as other fungi. Copyright © 2015 Elsevier Ltd. All rights reserved.

Active Immunizations with Peptide-DC Vaccines and Passive Transfer with Antibodies Protect Neutropenic Mice against Disseminated Candidiasis

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Xin, Hong

2015-01-01

We previously report that peptide-pulsed dendritic cell (DC) vaccination, which targeting two peptides (Fba and Met6) expressed on the cell surface of Candida albicans, can induce high degree of protection against disseminated candidiasis in immunocompetent mice. Passive transfer of immune sera from the peptide immunized mice or peptide-related monoclonal antibodies demonstrated that protection was medicated by peptide-specific antibodies. In this study the efficacy of active and passive immunization against disseminated candidiasis was tested in mice with cyclophosphamide-induced neutropenia. Peptide-DC vaccines were given to mice prior to induction of neutropenia. We show active immunization with either Fba or Met6 peptide-DC vaccine significantly improved the survival and reduced the fungal burden of disseminated candidiasis in those immunocompromised mice. Importantly, we show that administration of two protective monoclonal antibodies also protect neutropenic mice against the disease, implying possibility of developing a successful passive immunotherapy strategy to treat the disease and protect against disseminated candidiasis. The results of this study are crucial as they address the fundamental questions as to whether the synthetic peptide vaccine induced immunity protects the host during a neutropenic episode. We anticipate that this peptide-vaccine study will serve as the foundation of future investigations into new peptide vaccines comprised of cell surface peptides from other medically important Candida species, as well as other fungi. PMID:26620842

Vaccination with Recombinant Parainfluenza Virus 5 Expressing Neuraminidase Protects against Homologous and Heterologous Influenza Virus Challenge.

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Mooney, Alaina J; Gabbard, Jon D; Li, Zhuo; Dlugolenski, Daniel A; Johnson, Scott K; Tripp, Ralph A; He, Biao; Tompkins, S Mark

2017-12-01

Seasonal human influenza virus continues to cause morbidity and mortality annually, and highly pathogenic avian influenza (HPAI) viruses along with other emerging influenza viruses continue to pose pandemic threats. Vaccination is considered the most effective measure for controlling influenza; however, current strategies rely on a precise vaccine match with currently circulating virus strains for efficacy, requiring constant surveillance and regular development of matched vaccines. Current vaccines focus on eliciting specific antibody responses against the hemagglutinin (HA) surface glycoprotein; however, the diversity of HAs across species and antigenic drift of circulating strains enable the evasion of virus-inhibiting antibody responses, resulting in vaccine failure. The neuraminidase (NA) surface glycoprotein, while diverse, has a conserved enzymatic site and presents an appealing target for priming broadly effective antibody responses. Here we show that vaccination with parainfluenza virus 5 (PIV5), a promising live viral vector expressing NA from avian (H5N1) or pandemic (H1N1) influenza virus, elicited NA-specific antibody and T cell responses, which conferred protection against homologous and heterologous influenza virus challenges. Vaccination with PIV5-N1 NA provided cross-protection against challenge with a heterosubtypic (H3N2) virus. Experiments using antibody transfer indicate that antibodies to NA have an important role in protection. These findings indicate that PIV5 expressing NA may be effective as a broadly protective vaccine against seasonal influenza and emerging pandemic threats. IMPORTANCE Seasonal influenza viruses cause considerable morbidity and mortality annually, while emerging viruses pose potential pandemic threats. Currently licensed influenza virus vaccines rely on the antigenic match of hemagglutinin (HA) for vaccine strain selection, and most vaccines rely on HA inhibition titers to determine efficacy, despite the growing

Pan-Influenza A Protection by Prime-Boost Vaccination with Cold-Adapted Live-Attenuated Influenza Vaccine in a Mouse Model.

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Jang, Yo Han; Kim, Joo Young; Byun, Young Ho; Son, Ahyun; Lee, Jeong-Yoon; Lee, Yoon Jae; Chang, Jun; Seong, Baik Lin

2018-01-01

Influenza virus infections continually pose a major public health threat with seasonal epidemics and sporadic pandemics worldwide. While currently licensed influenza vaccines provide only strain-specific protection, antigenic drift and shift occasionally render the viruses resistant to the host immune responses, which highlight the need for a vaccine that provides broad protection against multiple subtypes. In this study, we suggest a vaccination strategy using cold-adapted, live attenuated influenza vaccines (CAIVs) to provide a broad, potent, and safe cross-protection covering antigenically distinct hemagglutinin (HA) groups 1 and 2 influenza viruses. Using a mouse model, we tested different prime-boost combinations of CAIVs for their ability to induce humoral and T-cell responses, and protective efficacy against H1 and H5 (HA group 1) as well as H3 and H7 (HA group 2) influenza viruses. Notably, even in the absence of antibody-mediated neutralizing activity or HA inhibitory activity in vitro , CAIVs provided a potent protection against heterologous and heterosubtypic lethal challenges in vivo . Heterologous combination of prime (H1)-boost (H5) vaccine strains showed the most potent cross-protection efficacy. In vivo depletion experiments demonstrated not only that T cells and natural killer cells contributed to the cross-protection, but also the involvement of antibody-dependent mechanisms for the cross-protection. Vaccination-induced antibodies did not enhance the infectivity of heterologous viruses, and prime vaccination did not interfere with neutralizing antibody generation by the boost vaccination, allaying vaccine safety concerns associated with heterogeneity between the vaccines and challenge strains. Our data show that CAIV-based strategy can serve as a simple but powerful option for developing a "truly" universal influenza vaccine providing pan-influenza A protection, which has not been achieved yet by other vaccine strategies. The promising results

Pan-Influenza A Protection by Prime–Boost Vaccination with Cold-Adapted Live-Attenuated Influenza Vaccine in a Mouse Model

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Jang, Yo Han; Kim, Joo Young; Byun, Young Ho; Son, Ahyun; Lee, Jeong-Yoon; Lee, Yoon Jae; Chang, Jun; Seong, Baik Lin

2018-01-01

Influenza virus infections continually pose a major public health threat with seasonal epidemics and sporadic pandemics worldwide. While currently licensed influenza vaccines provide only strain-specific protection, antigenic drift and shift occasionally render the viruses resistant to the host immune responses, which highlight the need for a vaccine that provides broad protection against multiple subtypes. In this study, we suggest a vaccination strategy using cold-adapted, live attenuated influenza vaccines (CAIVs) to provide a broad, potent, and safe cross-protection covering antigenically distinct hemagglutinin (HA) groups 1 and 2 influenza viruses. Using a mouse model, we tested different prime–boost combinations of CAIVs for their ability to induce humoral and T-cell responses, and protective efficacy against H1 and H5 (HA group 1) as well as H3 and H7 (HA group 2) influenza viruses. Notably, even in the absence of antibody-mediated neutralizing activity or HA inhibitory activity in vitro, CAIVs provided a potent protection against heterologous and heterosubtypic lethal challenges in vivo. Heterologous combination of prime (H1)–boost (H5) vaccine strains showed the most potent cross-protection efficacy. In vivo depletion experiments demonstrated not only that T cells and natural killer cells contributed to the cross-protection, but also the involvement of antibody-dependent mechanisms for the cross-protection. Vaccination-induced antibodies did not enhance the infectivity of heterologous viruses, and prime vaccination did not interfere with neutralizing antibody generation by the boost vaccination, allaying vaccine safety concerns associated with heterogeneity between the vaccines and challenge strains. Our data show that CAIV-based strategy can serve as a simple but powerful option for developing a “truly” universal influenza vaccine providing pan-influenza A protection, which has not been achieved yet by other vaccine strategies. The promising

Lessons Learned from Protective Immune Responses to Optimize Vaccines against Cryptosporidiosis

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Maxime W. Lemieux

2017-12-01

Full Text Available In developing countries, cryptosporidiosis causes moderate-to-severe diarrhea and kills thousands of infants and toddlers annually. Drinking and recreational water contaminated with Cryptosporidium spp. oocysts has led to waterborne outbreaks in developed countries. A competent immune system is necessary to clear this parasitic infection. A better understanding of the immune responses required to prevent or limit infection by this protozoan parasite is the cornerstone of development of an effective vaccine. In this light, lessons learned from previously developed vaccines against Cryptosporidium spp. are at the foundation for development of better next-generation vaccines. In this review, we summarize the immune responses elicited by naturally and experimentally-induced Cryptosporidium spp. infection and by several experimental vaccines in various animal models. Our aim is to increase awareness about the immune responses that underlie protection against cryptosporidiosis and to encourage promotion of these immune responses as a key strategy for vaccine development. Innate and mucosal immunity will be addressed as well as adaptive immunity, with an emphasis on the balance between TH1/TH2 immune responses. Development of more effective vaccines against cryptosporidiosis is needed to prevent Cryptosporidium spp.-related deaths in infants and toddlers in developing countries.

Age and long-term protective immunity in dogs and cats.

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Schultz, R D; Thiel, B; Mukhtar, E; Sharp, P; Larson, L J

2010-01-01

Vaccination can provide an immune response that is similar in duration to that following a natural infection. In general, adaptive immunity to viruses develops earliest and is highly effective. Such anti-viral immune responses often result in the development of sterile immunity and the duration of immunity (DOI) is often lifelong. In contrast, adaptive immunity to bacteria, fungi or parasites develops more slowly and the DOI is generally short compared with most systemic viral infections. Sterile immunity to these infectious agents is less commonly engendered. Old dogs and cats rarely die from vaccine-preventable infectious disease, especially when they have been vaccinated and immunized as young adults (i.e. between 16 weeks and 1 year of age). However, young animals do die, often because vaccines were either not given or not given at an appropriate age (e.g. too early in life in the presence of maternally derived antibody [MDA]). More animals need to be vaccinated to increase herd (population) immunity. The present study examines the DOI for core viral vaccines in dogs that had not been revaccinated for as long as 9 years. These animals had serum antibody to canine distemper virus (CDV), canine parvovirus type 2 (CPV-2) and canine adenovirus type-1 (CAV-1) at levels considered protective and when challenged with these viruses, the dogs resisted infection and/or disease. Thus, even a single dose of modified live virus (MLV) canine core vaccines (against CDV, cav-2 and cpv-2) or MLV feline core vaccines (against feline parvovirus [FPV], feline calicivirus [FCV] and feline herpesvirus [FHV]), when administered at 16 weeks or older, could provide long-term immunity in a very high percentage of animals, while also increasing herd immunity. Copyright 2009 Elsevier Ltd. All rights reserved.

Highly immunogenic prime–boost DNA vaccination protects chickens against challenge with homologous and heterologous H5N1 virus

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Anna Stachyra

2014-01-01

Full Text Available Highly pathogenic avian influenza viruses (HPAIVs cause huge economic losses in the poultry industry because of high mortality rate in infected flocks and trade restrictions. Protective antibodies, directed mainly against hemagglutinin (HA, are the primary means of protection against influenza outbreaks. A recombinant DNA vaccine based on the sequence of H5 HA from the H5N1/A/swan/Poland/305-135V08/2006 strain of HPAIV was prepared. Sequence manipulation included deletion of the proteolytic cleavage site to improve protein stability, codon usage optimization to improve translation and stability of RNA in host cells, and cloning into a commercially available vector to enable expression in animal cells. Naked plasmid DNA was complexed with a liposomal carrier and the immunization followed the prime–boost strategy. The immunogenic potential of the DNA vaccine was first proved in broilers in near-to-field conditions resembling a commercial farm. Next, the protective activity of the vaccine was confirmed in SPF layer-type chickens. Experimental infections (challenge experiments indicated that 100% of vaccinated chickens were protected against H5N1 of the same clade and that 70% of them were protected against H5N1 influenza virus of a different clade. Moreover, the DNA vaccine significantly limited (or even eliminated transmission of the virus to contact control chickens. Two intramuscular doses of DNA vaccine encoding H5 HA induced a strong protective response in immunized chicken. The effective protection lasted for a minimum 8 weeks after the second dose of the vaccine and was not limited to the homologous H5N1 virus. In addition, the vaccine reduced shedding of the virus.

New insights into enterocin CRL35: mechanism of action and immunity revealed by heterologous expression in Escherichia coli.

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Barraza, Daniela E; Ríos Colombo, Natalia S; Galván, Adriana E; Acuña, Leonardo; Minahk, Carlos J; Bellomio, Augusto; Chalón, Miriam C

2017-09-01

The role of the class IIa bacteriocin membrane receptor protein remains unclear, and the following two different mechanisms have been proposed: the bacteriocin could interact with the receptor changing it to an open conformation or the receptor might act as an anchor allowing subsequent bacteriocin insertion and membrane disruption. Bacteriocin-producing cells synthesize an immunity protein that forms an inactive bacteriocin-receptor-immunity complex. To better understand the molecular mechanism of enterocin CRL35, the peptide was expressed as the suicidal probe EtpM-enterocin CRL35 in Escherichia coli, a naturally insensitive microorganism since it does not express the receptor. When the bacteriocin is anchored to the periplasmic face of the plasma membrane through the bitopic membrane protein, EtpM , E. coli cells depolarize and die. Moreover, co-expression of the immunity protein prevents the deleterious effect of EtpM-enterocin CRL35. The binding and anchoring of the bacteriocin to the membrane has demonstrated to be a sufficient condition for its membrane insertion. The final step of membrane disruption by EtpM-enterocin CRL35 is independent from the receptor, which means that the mannose PTS might not be involved in the pore structure. In addition, the immunity protein can protect even in the absence of the receptor. © 2017 John Wiley & Sons Ltd.

A recombinant anchorless respiratory syncytial virus (RSV) fusion (F) protein/monophosphoryl lipid A (MPL) vaccine protects against RSV-induced replication and lung pathology.

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Blanco, Jorge C G; Boukhvalova, Marina S; Pletneva, Lioubov M; Shirey, Kari Ann; Vogel, Stefanie N

2014-03-14

We previously demonstrated that the severe cytokine storm and pathology associated with RSV infection following intramuscular vaccination of cotton rats with FI-RSV Lot 100 could be completely abolished by formulating the vaccine with the mild TLR4 agonist and adjuvant, monophosphoryl lipid A (MPL). Despite this significant improvement, the vaccine failed to blunt viral replication in the lungs. Since MPL is a weak TLR4 agonist, we hypothesized that its adjuvant activity was mediated by modulating the innate immune response of respiratory tract resident macrophages. Therefore, we developed a new vaccine preparation with purified, baculovirus expressed, partially purified, anchorless RSV F protein formulated with synthetic MPL that was administered to cotton rats intranasally, followed by an intradermal boost. This novel formulation and heterologous "prime/boost" route of administration resulted in decreased viral titers compared to that seen in animals vaccinated with F protein alone. Furthermore, animals vaccinated by this route showed no evidence of enhanced lung pathology upon RSV infection. This indicates that MPL acts as an immune modulator that protects the host from vaccine-enhanced pathology, and reduces RSV replication in the lower respiratory tract when administered by a heterologous prime/boost immunization regimen. Copyright © 2013 Elsevier Ltd. All rights reserved.

Immunization with lipopolysaccharide-deficient whole cells provides protective immunity in an experimental mouse model of Acinetobacter baumannii infection.

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Meritxell García-Quintanilla

Full Text Available The increasing clinical importance of infections caused by multidrug resistant Acinetobacter baumannii warrants the development of novel approaches for prevention and treatment. In this context, vaccination of certain patient populations may contribute to reducing the morbidity and mortality caused by this pathogen. Vaccines against Gram-negative bacteria based on inactivated bacterial cells are highly immunogenic and have been shown to produce protective immunity against a number of bacterial species. However, the high endotoxin levels present in these vaccines due to the presence of lipopolysaccharide complicates their use in human vaccination. In the present study, we used a laboratory-derived strain of A. baumannii that completely lacks lipopolysaccharide due to a mutation in the lpxD gene (IB010, one of the genes involved in the first steps of lipopolysaccharide biosynthesis, for vaccination. We demonstrate that IB010 has greatly reduced endotoxin content (<1.0 endotoxin unit/106 cells compared to wild type cells. Immunization with formalin inactivated IB010 produced a robust antibody response consisting of both IgG1 and IgG2c subtypes. Mice immunized with IB010 had significantly lower post-infection tissue bacterial loads and significantly lower serum levels of the pro-inflammatory cytokines IL-1β, TNF-α and IL-6 compared to control mice in a mouse model of disseminated A. baumannii infection. Importantly, immunized mice were protected from infection with the ATCC 19606 strain and an A. baumannii clinical isolate. These data suggest that immunization with inactivated A. baumannii whole cells deficient in lipopolysaccharide could serve as the basis for a vaccine for the prevention of infection caused by A. baumannii.

Protective Immunity and Reduced Renal Colonization Induced by Vaccines Containing Recombinant Leptospira interrogans Outer Membrane Proteins and Flagellin Adjuvant

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Monaris, D.; Sbrogio-Almeida, M. E.; Dib, C. C.; Canhamero, T. A.; Souza, G. O.; Vasconcellos, S. A.; Ferreira, L. C. S.

2015-01-01

Leptospirosis is a global zoonotic disease caused by different Leptospira species, such as Leptospira interrogans, that colonize the renal tubules of wild and domestic animals. Thus far, attempts to develop effective leptospirosis vaccines, both for humans and animals, have failed to induce immune responses capable of conferring protection and simultaneously preventing renal colonization. In this study, we evaluated the protective immunity induced by subunit vaccines containing seven different recombinant Leptospira interrogans outer membrane proteins, including the carboxy-terminal portion of the immunoglobulinlike protein A (LigAC) and six novel antigens, combined with aluminum hydroxide (alum) or Salmonella flagellin (FliC) as adjuvants. Hamsters vaccinated with the different formulations elicited high antigen-specific antibody titers. Immunization with LigAC, either with alum or flagellin, conferred protective immunity but did not prevent renal colonization. Similarly, animals immunized with LigAC or LigAC coadministered with six leptospiral proteins with alum adjuvant conferred protection but did not reduce renal colonization. In contrast, immunizing animals with the pool of seven antigens in combination with flagellin conferred protection and significantly reduced renal colonization by the pathogen. The present study emphasizes the relevance of antigen composition and added adjuvant in the efficacy of antileptospirosis subunit vaccines and shows the complex relationship between immune responses and renal colonization by the pathogen. PMID:26108285

Protective effect of intranasal immunization with Neospora caninum membrane antigens against murine neosporosis established through the gastrointestinal tract

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Ferreirinha, Pedro; Dias, Joana; Correia, Alexandra; Pérez-Cabezas, Begoña; Santos, Carlos; Teixeira, Luzia; Ribeiro, Adília; Rocha, António; Vilanova, Manuel

2014-01-01

Neospora caninum is an Apicomplexa parasite that in the last two decades was acknowledged as the main pathogenic agent responsible for economic losses in the cattle industry. In the present study, the effectiveness of intranasal immunization with N. caninum membrane antigens plus CpG adjuvant was assessed in a murine model of intragastrically established neosporosis. Immunized mice presented a lower parasitic burden in the brain on infection with 5 × 107 tachyzoites, showing that significant protection was achieved by this immunization strategy. Intestinal IgA antibodies raised by immunization markedly agglutinated live N. caninum tachyzoites whereas previous opsonization with IgG antibodies purified from immunized mice sera reduced parasite survival within macrophage cells. Although an IgG1 : IgG2a ratio < 1 was detected in the immunized mice before and after infection, indicative of a predominant T helper type 1 immune response, no increased production of interferon-γ was detected in the spleen or mesenteric lymph nodes of the immunized mice. Altogether, these results show that mucosal immunization with N. caninum membrane proteins plus CpG adjuvant protect against intragastrically established neosporosis and indicate that parasite-specific mucosal and circulating antibodies have a protective role against this parasitic infection. PMID:24128071

Role of pro-inflammatory cytokine IL-17 in Leishmania pathogenesis and in protective immunity by Leishmania vaccines.

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Banerjee, Antara; Bhattacharya, Parna; Joshi, Amritanshu B; Ismail, Nevien; Dey, Ranadhir; Nakhasi, Hira L

2016-11-01

The clinical outcome of Leishmania pathogenesis ranges from active skin lesions to fatal visceral dissemination and severely impaired T cell immunity. It is well established that a strong Th1 immune response is protective against cutaneous forms of the disease, however a mixed Th1/Th2 response is most commonly observed against visceral infections as evident from previous studies. Aside from Th1/Th2 cytokines, the pro-inflammatory IL-17 cytokine family plays an important role in the clearance of intracellular pathogens. In Leishmania induced skin lesions, IL-17 produced by Th17 cells is shown to exacerbate the disease, suggesting a role in pathogenesis. However, a protective role for IL-17 is indicated by the expansion of IL-17 producing cells in vaccine-induced immunity. In human visceral leishmaniasis (VL) it has been demonstrated that IL-17 and IL-22 are associated with protection against re-exposure to Leishmania, which further suggests the involvement of IL-17 in vaccine induced protective immunity. Although there is no vaccine against any form of leishmaniasis, the development of genetically modified live attenuated parasites as vaccine candidates prove to be promising, as they successfully induce a robust protective immune response in various animal models. However, the role of IL-17 producing cells and Th17 cells in response to these vaccine candidates remains unexplored. In this article, we review the role of IL-17 in Leishmania pathogenesis and the potential impact on vaccine induced immunity, with a special focus on live attenuated Leishmania parasites. Published by Elsevier Inc.

Yeast-expressed recombinant As16 protects mice against Ascaris suum infection through induction of a Th2-skewed immune response.

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Junfei Wei

2017-07-01

Full Text Available Ascariasis remains the most common helminth infection in humans. As an alternative or complementary approach to global deworming, a pan-anthelminthic vaccine is under development targeting Ascaris, hookworm, and Trichuris infections. As16 and As14 have previously been described as two genetically related proteins from Ascaris suum that induced protective immunity in mice when formulated with cholera toxin B subunit (CTB as an adjuvant, but the exact protective mechanism was not well understood.As16 and As14 were highly expressed as soluble recombinant proteins (rAs16 and rAs14 in Pichia pastoris. The yeast-expressed rAs16 was highly recognized by immune sera from mice infected with A. suum eggs and elicited 99.6% protection against A. suum re-infection. Mice immunized with rAs16 formulated with ISA720 displayed significant larva reduction (36.7% and stunted larval development against A. suum eggs challenge. The protective immunity was associated with a predominant Th2-type response characterized by high titers of serological IgG1 (IgG1/IgG2a > 2000 and high levels of IL-4 and IL-5 produced by restimulated splenocytes. A similar level of protection was observed in mice immunized with rAs16 formulated with alum (Alhydrogel, known to induce mainly a Th2-type immune response, whereas mice immunized with rAs16 formulated with MPLA or AddaVax, both known to induce a Th1-type biased response, were not significantly protected against A. suum infection. The rAs14 protein was not recognized by A. suum infected mouse sera and mice immunized with rAs14 formulated with ISA720 did not show significant protection against challenge infection, possibly due to the protein's inaccessibility to the host immune system or a Th1-type response was induced which would counter a protective Th2-type response.Yeast-expressed rAs16 formulated with ISA720 or alum induced significant protection in mice against A. suum egg challenge that associates with a Th2-skewed immune

Induction of protective immune responses in mice by double DNA ...

African Journals Online (AJOL)

Purpose: To investigate the efficacy of a double DNA vaccine encoding of Brucella melitensis omp31 gene and of Escherichia coli eae gene in inducing protective immune response in a mouse model. Methods: After performing PCR assays and cloning both the eae and omp31 genes, the generated DNA vaccines were ...

Studies on the protection effects of functional foods for skin immune system from radiation damage

International Nuclear Information System (INIS)

Yee, Sung Tae; Shin, Seong Hae; Kim, Do Sun; Heo, Ji Yun; Kang, Hye In

2007-07-01

We evaluated the protective effects of pilot products (HemoHIM and HemoTonic) on the UV-induced skin immune damages as the following. · Protective effects of HemoHIM and HemoTonic against UV using contact hypersensitivity model - Protection against depression of contact hypersensitivity by administration and skin application of HemoHIM and HemoTonic - Induction of dendritic cell differentiation and maturation by HemoHIM and HemoTonic treatment - Improvement of antigen-presenting activity of dedritic cells by HemoHIM and HemoTonic treatment · Protective effects of HemoHIM and HemoTonic on skin immune system against UV-irradiation - Protection of antigen-presenting activity of dendritic cells under UV-irradiation - In vivo protection of antigen-presenting activity of Langerhans cells in UV-irradiated mice · Protective effects of HemoHIM on UV-induced apoptosis of dendritic cells - Inhibition of cell membrane change, mitochondrial potential change, SubG1 cell population, nuclear condensation, and DNA fragmentation in UV-irradiated dendritic cells · Anti-allergic effects of HemoHIM and HemoTonic in human adipocyte HMC-1 cells - Inhibition of allergic histamine release from adipocytes - Inhibition of secretion of inflammatory cytokines (IL-6, IL-8, TNF-α, GM-CSF) - Inhibition of c-kit, tryptase, FcεRI mRNA expression From these results, the developed functional food products (HemoHIM, HemoTonic) showed the protection and recovery of the immune functions in the UV-irradiated skin. It is suggested that these products may be used as a new functional food or cosmetic material for the protection of skin damage and the promotion of recovery

Protective MCMV immunity by vaccination of the salivary gland via Wharton's duct: replication-deficient recombinant adenovirus expressing individual MCMV genes elicits protection similar to that of MCMV.

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Liu, Guangliang; Zhang, Fangfang; Wang, Ruixue; London, Lucille; London, Steven D

2014-04-01

Salivary glands, a major component of the mucosal immune system, confer antigen-specific immunity to mucosally acquired pathogens. We investigated whether a physiological route of inoculation and a subunit vaccine approach elicited MCMV-specific and protective immunity. Mice were inoculated by retrograde perfusion of the submandibular salivary glands via Wharton's duct with tcMCMV or MCMV proteins focused to the salivary gland via replication-deficient adenovirus expressing individual MCMV genes (gB, gH, IE1; controls: saline and replication deficient adenovirus without MCMV inserts). Mice were evaluated for MCMV-specific antibodies, T-cell responses, germinal center formation, and protection against a lethal MCMV challenge. Retrograde perfusion with tcMCMV or adenovirus expressed MCMV proteins induced a 2- to 6-fold increase in systemic and mucosal MCMV-specific antibodies, a 3- to 6-fold increase in GC marker expression, and protection against a lethal systemic challenge, as evidenced by up to 80% increased survival, decreased splenic pathology, and decreased viral titers from 10(6) pfu to undetectable levels. Thus, a focused salivary gland immunization via a physiological route with a protein antigen induced systemic and mucosal protective immune responses. Therefore, salivary gland immunization can serve as an alternative mucosal route for administering vaccines, which is directly applicable for use in humans.

Subunit Rotavirus Vaccine Administered Parenterally to Rabbits Induces Active Protective Immunity

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Ciarlet, Max; Crawford, Sue E.; Barone, Christopher; Bertolotti-Ciarlet, Andrea; Ramig, Robert F.; Estes, Mary K.; Conner, Margaret E.

1998-01-01

Virus-like particles (VLPs) are being evaluated as a candidate rotavirus vaccine. The immunogenicity and protective efficacy of different formulations of VLPs administered parenterally to rabbits were tested. Two doses of VLPs (2/6-, G3 2/6/7-, or P[2], G3 2/4/6/7-VLPs) or SA11 simian rotavirus in Freund’s adjuvants, QS-21 (saponin adjuvant), or aluminum phosphate (AlP) were administered. Serological and mucosal immune responses were evaluated in all vaccinated and control rabbits before and after oral challenge with 103 50% infective doses of live P[14], G3 ALA lapine rotavirus. All VLP- and SA11-vaccinated rabbits developed high levels of rotavirus-specific serum and intestinal immunoglobulin G (IgG) antibodies but not intestinal IgA antibodies. SA11 and 2/4/6/7-VLPs afforded similar but much higher mean levels of protection than 2/6/7- or 2/6-VLPs in QS-21. The presence of neutralizing antibodies to VP4 correlated (P < 0.001, r = 0.55; Pearson’s correlation coefficient) with enhanced protection rates, suggesting that these antibodies are important for protection. Although the inclusion of VP4 resulted in higher mean protection levels, high levels of protection (87 to 100%) from infection were observed in individual rabbits immunized with 2/6/7- or 2/6-VLPs in Freund’s adjuvants. Therefore, neither VP7 nor VP4 was absolutely required to achieve protection from infection in the rabbit model when Freund’s adjuvant was used. Our results show that VLPs are immunogenic when administered parenterally to rabbits and that Freund’s adjuvant is a better adjuvant than QS-21. The use of the rabbit model may help further our understanding of the critical rotavirus proteins needed to induce active protection. VLPs are a promising candidate for a parenterally administered subunit rotavirus vaccine. PMID:9765471

A single immunization with a recombinant canine adenovirus expressing the rabies virus G protein confers protective immunity against rabies in mice

International Nuclear Information System (INIS)

Li Jianwei; Faber, Milosz; Papaneri, Amy; Faber, Marie-Luise; McGettigan, James P.; Schnell, Matthias J.; Dietzschold, Bernhard

2006-01-01

Rabies vaccines based on live attenuated rabies viruses or recombinant pox viruses expressing the rabies virus (RV) glycoprotein (G) hold the greatest promise of safety and efficacy, particularly for oral immunization of wildlife. However, while these vaccines induce protective immunity in foxes, they are less effective in other animals, and safety concerns have been raised for some of these vaccines. Because canine adenovirus 2 (CAV2) is licensed for use as a live vaccine for dogs and has an excellent efficacy and safety record, we used this virus as an expression vector for the RVG. The recombinant CAV2-RV G produces virus titers similar to those produced by wild-type CAV2, indicating that the RVG gene does not affect virus replication. Comparison of RVG expressed by CAV2-RV G with that of vaccinia-RV G recombinant virus (V-RG) revealed similar amounts of RV G on the cell surface. A single intramuscular or intranasal immunization of mice with CAV2-RVG induced protective immunity in a dose-dependent manner, with no clinical signs or discomfort from the virus infection regardless of the route of administration or the amount of virus

The evolutionarily conserved mediator subunit MDT-15/MED15 links protective innate immune responses and xenobiotic detoxification.

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Read Pukkila-Worley

2014-05-01

Full Text Available Metazoans protect themselves from environmental toxins and virulent pathogens through detoxification and immune responses. We previously identified a small molecule xenobiotic toxin that extends survival of Caenorhabditis elegans infected with human bacterial pathogens by activating the conserved p38 MAP kinase PMK-1 host defense pathway. Here we investigate the cellular mechanisms that couple activation of a detoxification response to innate immunity. From an RNAi screen of 1,420 genes expressed in the C. elegans intestine, we identified the conserved Mediator subunit MDT-15/MED15 and 28 other gene inactivations that abrogate the induction of PMK-1-dependent immune effectors by this small molecule. We demonstrate that MDT-15/MED15 is required for the xenobiotic-induced expression of p38 MAP kinase PMK-1-dependent immune genes and protection from Pseudomonas aeruginosa infection. We also show that MDT-15 controls the induction of detoxification genes and functions to protect the host from bacteria-derived phenazine toxins. These data define a central role for MDT-15/MED15 in the coordination of xenobiotic detoxification and innate immune responses.

The evolutionarily conserved mediator subunit MDT-15/MED15 links protective innate immune responses and xenobiotic detoxification.

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Pukkila-Worley, Read; Feinbaum, Rhonda L; McEwan, Deborah L; Conery, Annie L; Ausubel, Frederick M

2014-05-01

Metazoans protect themselves from environmental toxins and virulent pathogens through detoxification and immune responses. We previously identified a small molecule xenobiotic toxin that extends survival of Caenorhabditis elegans infected with human bacterial pathogens by activating the conserved p38 MAP kinase PMK-1 host defense pathway. Here we investigate the cellular mechanisms that couple activation of a detoxification response to innate immunity. From an RNAi screen of 1,420 genes expressed in the C. elegans intestine, we identified the conserved Mediator subunit MDT-15/MED15 and 28 other gene inactivations that abrogate the induction of PMK-1-dependent immune effectors by this small molecule. We demonstrate that MDT-15/MED15 is required for the xenobiotic-induced expression of p38 MAP kinase PMK-1-dependent immune genes and protection from Pseudomonas aeruginosa infection. We also show that MDT-15 controls the induction of detoxification genes and functions to protect the host from bacteria-derived phenazine toxins. These data define a central role for MDT-15/MED15 in the coordination of xenobiotic detoxification and innate immune responses.

Early infections by myxoma virus of young rabbits (Oryctolagus cuniculus) protected by maternal antibodies activate their immune system and enhance herd immunity in wild populations.

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Marchandeau, Stéphane; Pontier, Dominique; Guitton, Jean-Sébastien; Letty, Jérôme; Fouchet, David; Aubineau, Jacky; Berger, Francis; Léonard, Yves; Roobrouck, Alain; Gelfi, Jacqueline; Peralta, Brigitte; Bertagnoli, Stéphane

2014-03-04

The role of maternal antibodies is to protect newborns against acute early infection by pathogens. This can be achieved either by preventing any infection or by allowing attenuated infections associated with activation of the immune system, the two strategies being based on different cost/benefit ratios. We carried out an epidemiological survey of myxomatosis, which is a highly lethal infectious disease, in two distant wild populations of rabbits to describe the epidemiological pattern of the disease. Detection of specific IgM and IgG enabled us to describe the pattern of immunity. We show that maternal immunity attenuates early infection of juveniles and enables activation of their immune system. This mechanism associated with steady circulation of the myxoma virus in both populations, which induces frequent reinfections of immune rabbits, leads to the maintenance of high immunity levels within populations. Thus, myxomatosis has a low impact, with most infections being asymptomatic. This work shows that infection of young rabbits protected by maternal antibodies induces attenuated disease and activates their immune system. This may play a major role in reducing the impact of a highly lethal disease when ecological conditions enable permanent circulation of the pathogen.

Multivalent HA DNA vaccination protects against highly pathogenic H5N1 avian influenza infection in chickens and mice.

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Srinivas Rao

Full Text Available Sustained outbreaks of highly pathogenic avian influenza (HPAI H5N1 in avian species increase the risk of reassortment and adaptation to humans. The ability to contain its spread in chickens would reduce this threat and help maintain the capacity for egg-based vaccine production. While vaccines offer the potential to control avian disease, a major concern of current vaccines is their potency and inability to protect against evolving avian influenza viruses.The ability of DNA vaccines encoding hemagglutinin (HA proteins from different HPAI H5N1 serotypes was evaluated for its ability to elicit neutralizing antibodies and to protect against homologous and heterologous HPAI H5N1 strain challenge in mice and chickens after DNA immunization by needle and syringe or with a pressure injection device. These vaccines elicited antibodies that neutralized multiple strains of HPAI H5N1 when given in combinations containing up to 10 HAs. The response was dose-dependent, and breadth was determined by the choice of the influenza virus HA in the vaccine. Monovalent and trivalent HA vaccines were tested first in mice and conferred protection against lethal H5N1 A/Vietnam/1203/2004 challenge 68 weeks after vaccination. In chickens, protection was observed against heterologous strains of HPAI H5N1 after vaccination with a trivalent H5 serotype DNA vaccine with doses as low as 5 microg DNA given twice either by intramuscular needle injection or with a needle-free device.DNA vaccines offer a generic approach to influenza virus immunization applicable to multiple animal species. In addition, the ability to substitute plasmids encoding different strains enables rapid adaptation of the vaccine to newly evolving field isolates.

Cellular and humoral immunity are synergistic in protection against types A and B Francisella tularensis.

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Sebastian, Shite; Pinkham, Jessica T; Lynch, Jillian G; Ross, Robin A; Reinap, Barbara; Blalock, Leeann T; Conlan, J Wayne; Kasper, Dennis L

2009-01-22

Herein we report studies with a novel combination vaccine that, when administered to mice, conferred protection against highly virulent strains of Francisella tularensis by stimulating both arms of the immune system. Our earlier studies with Ft.LVS::wbtA, an O-polysaccharide (OPS)-negative mutant derived from the available live vaccine strain of F. tularensis (Ft.LVS), elucidated the role of antibodies to the OPS - a key virulence determinant - in protection against virulent type A organisms. However, when expressed on the organism, the OPS enhances virulence. In contrast, in purified form, the OPS is completely benign. We hypothesized that a novel combination vaccine containing both a component that induces humoral immunity and a component that induces cellular immunity to this intracellular microbe would have an enhanced protective capacity over either component alone and would be much safer than the LVS vaccine. Thus we developed a combination vaccine containing both OPS (supplied in an OPS-tetanus toxoid glycoconjugate) to induce a humoral antibody response and strain Ft.LVS::wbtA (which is markedly attenuated by its lack of OPS) to induce a cell-mediated protective response. This vaccine protected mice against otherwise-lethal intranasal and intradermal challenge with wild-type F. tularensis strains Schu S4 (type A) and FSC 108 (type B). These results represent a significant advance in our understanding of immunity to F. tularensis and provide important insight into the development of a safer vaccine effective against infections caused by clinical type A and B strains of F. tularensis.

Association of the Host Immune Response with Protection Using a Live Attenuated African Swine Fever Virus Model.

Science.gov (United States)

Carlson, Jolene; O'Donnell, Vivian; Alfano, Marialexia; Velazquez Salinas, Lauro; Holinka, Lauren G; Krug, Peter W; Gladue, Douglas P; Higgs, Stephen; Borca, Manuel V

2016-10-22

African swine fever (ASF) is a lethal hemorrhagic disease of swine caused by a double-stranded DNA virus, ASF virus (ASFV). There is no vaccine to prevent the disease and current control measures are limited to culling and restricting animal movement. Swine infected with attenuated strains are protected against challenge with a homologous virulent virus, but there is limited knowledge of the host immune mechanisms generating that protection. Swine infected with Pretoriuskop/96/4 (Pret4) virus develop a fatal severe disease, while a derivative strain lacking virulence-associated gene 9GL (Pret4Δ9GL virus) is completely attenuated. Swine infected with Pret4Δ9GL virus and challenged with the virulent parental virus at 7, 10, 14, 21, and 28 days post infection (dpi) showed a progressive acquisition of protection (from 40% at 7 dpi to 80% at 21 and 28 dpi). This animal model was used to associate the presence of host immune response (ASFV-specific antibody and interferon (IFN)-γ responses, or specific cytokine profiles) and protection against challenge. With the exception of ASFV-specific antibodies in survivors challenged at 21 and 28 dpi, no association between the parameters assessed and protection could be established. These results, encompassing data from 65 immunized swine, underscore the complexity of the system under study, suggesting that protection relies on the concurrence of different host immune mechanisms.

Salmonella enterica serovar Typhimurium lacking hfq gene confers protective immunity against murine typhoid.

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Uday Shankar Allam

Full Text Available Salmonella enterica is an important enteric pathogen and its various serovars are involved in causing both systemic and intestinal diseases in humans and domestic animals. The emergence of multidrug-resistant strains of Salmonella leading to increased morbidity and mortality has further complicated its management. Live attenuated vaccines have been proven superior over killed or subunit vaccines due to their ability to induce protective immunity. Of the various strategies used for the generation of live attenuated vaccine strains, focus has gradually shifted towards manipulation of virulence regulator genes. Hfq is a RNA chaperon which mediates the binding of small RNAs to the mRNA and assists in post-transcriptional gene regulation in bacteria. In this study, we evaluated the efficacy of the Salmonella Typhimurium Δhfq strain as a candidate for live oral vaccine in murine model of typhoid fever. Salmonella hfq deletion mutant is highly attenuated in cell culture and animal model implying a significant role of Hfq in bacterial virulence. Oral immunization with the Salmonella hfq deletion mutant efficiently protects mice against subsequent oral challenge with virulent strain of Salmonella Typhimurium. Moreover, protection was induced upon both multiple as well as single dose of immunizations. The vaccine strain appears to be safe for use in pregnant mice and the protection is mediated by the increase in the number of CD4(+ T lymphocytes upon vaccination. The levels of serum IgG and secretory-IgA in intestinal washes specific to lipopolysaccharide and outer membrane protein were significantly increased upon vaccination. Furthermore, hfq deletion mutant showed enhanced antigen presentation by dendritic cells compared to the wild type strain. Taken together, the studies in murine immunization model suggest that the Salmonella hfq deletion mutant can be a novel live oral vaccine candidate.

Cell-mediated immune responses in rainbow trout after DNA immunization against the viral hemorrhagic septicemia virus

DEFF Research Database (Denmark)

Utke, Katrin; Kock, Holger; Schuetze, Heike

2008-01-01

injection site rather than to injection sites of heterologous vaccines, suggesting the antigen specificity of homing. By demonstrating CMC responses to distinct viral proteins and homing in rainbow trout, these results substantially contribute to the understanding of the teleost immune system.......To identify viral proteins that induce cell-mediated cytotoxicity (CMC) against viral hemorrhagic septicemia virus (VHSV)-infected cells, rainbow trout were immunized with DNA vectors encoding the glycoprotein G or the nucleocapsid protein N of VHSV. The G protein was a more potent trigger...... of cytotoxic cells than the N protein. Peripheral blood leukocytes (PBL) isolated from trout immunized against the G protein killed both VHSV-infected MHC class I matched (RTG-2) and VHSV-infected xenogeneic (EPC) target cells, suggesting the involvement of both cytotoxic T lymphocytes (CTL) and NK cells...

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

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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.

ANTIGENIC RELATEDNESS OF SELECTED FLAVIVIRUSES: STUDY WITH HOMOLOGOUS AND HETEROLOGOUS IMMUNE MOUSE ASCITIC FLUIDS

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S.S. BABA

1998-11-01

Full Text Available The antigenic relationship of 9 flaviviruses, Yellow fever (YF , Wesselsbron (WSL , Uganda S (UGS , Potiskum (POT, West Nile (WN , Banzi (BAN , Zika (ZK , Dengue type 1 (DEN-1 and Dengue type 2 (DEN-2, was assessed by cross-haemagglutination-inhibition (Cross-HI and cross-complement fixation (Cross-CF reactions between each of the viruses and their homologous immune mouse ascitic fluids. Titre ratios were calculated using the heterologous and homologous titres. Cross-CF reactions revealed wider antigenic variations among viruses than Cross-HI reactions. There was no significant antigenic variation between WSL, POT and YF viruses using either of those methods. However, definite differences in antigenicity were observed between them and UGS, BAN and ZK viruses. There were no significant differences between UGS, BAN and ZK or between DEN-1 and DEN-2. The serological relationship among flaviviruses is important in establishing diagnosis and epidemiology of these infections in Africa.A relação antigênica de 9 Flavivirus, Febre amarela (YF, Wesselsbron (WSL, Uganda S (UGS, Potiskum (POT, West Nile (WN, Banzi (BAN, Zika (ZK, Dengue tipo 1 (DEN-1 e Dengue tipo2 (DEN-2, foi avaliada por reação de inibição da hemaglutinação cruzada (cross-HI e reação de fixação do complemento cruzada (Cross-CF entre cada um dos virus e seu fluido ascítico homólogo em camundongos. Médias de títulos foram calculadas usando os títulos heterólogos e homólogos. Reações cruzadas CF revelaram maiores variações antigênicas entre virus do que reações cruzadas HI. Não houve variação antigênica significativa entre virus WSL, POT e YF usando cada um dos métodos. Todavia, diferenças definidas da antigenicidade foram observadas entre eles e os vírus UGS, BAN e ZK. Não existiram diferenças significativas entre UGS, BAN e ZK ou entre DEN-1 e DEN-2. A relação sorológica entre Flavivirus é importante para se estabelecer o diagnóstico e a

Protection against heterologous infection by using cross antigenicity between schistosoma mansoni and fasciola hepatica

International Nuclear Information System (INIS)

Moawad, M.A.; Amin, M.M.

2004-01-01

Fasciola hepatica is the causative agent of fasciolosis in many areas in America, Europe, Africa, Asia and Australia. There is an urgent need for improved methods to control the parasite's transmission. The present study is parasitological, immunological (interleukine-1β and interleukine-6) and histopathological investigations on the immunizing effect of cross antigenicity between S. mansoni and F. hepatica against schistosomiasis and fasciolosis in mice. Parasitological study showed that vaccination with irradiated cercariae of S. mansoni or vaccination by F. hepatica whole worm extract (FhWWE) before challenged with encysted metacercariae of F. hepatica or cercariae of S. mansoni played a significant control on the parasitic infection manifested by a remarkable reduction in the means of worm count. Assessment of IL-1β and IL-6 in sera of the experimental groups showed that there are cross reactivity between fasciola / schistosoma and its relation to cross protection. Histopathological examination of vaccinated mice livers showed protection against parasite maturation and liver damage after challenged, as compared to mice infected only without vaccination

Can VHS virus bypass the protective immunity induced by DNA vaccination in rainbow trout?

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Sepúlveda, Dagoberto; Lorenzen, Niels

2016-01-01

DNA vaccines encoding viral glycoproteins have been very successful for induction of protective immunity against diseases caused by rhabdoviruses in cultured fish species. However, the vaccine concept is based on a single viral gene and since RNA viruses are known to possess high variability...... and adaptation capacity, this work aimed at evaluating whether viral haemorrhagic septicaemia virus (VHSV), an RNA virus and member of Rhabdoviridae family, was able to evade the protective immune response induced by the DNA vaccination of rainbow trout. The experiments comprised repeated passages of a highly...... pathogenic VHSV isolate in a fish cell line in the presence of neutralizing fish serum (in vitro approach), and in rainbow trout immunized with the VHS DNA vaccine (in vivo approach). For the in vitro approach, the virus collected from the last passage (passaged virus) was as sensitive as the parental virus...

Long-Term Protective Immune Response Elicited by Vaccination with an Expression Genomic Library of Toxoplasma gondii

OpenAIRE

Fachado, Alberto; Rodriguez, Alexandro; Molina, Judith; Silvério, Jaline C.; Marino, Ana P. M. P.; Pinto, Luzia M. O.; Angel, Sergio O.; Infante, Juan F.; Traub-Cseko, Yara; Amendoeira, Regina R.; Lannes-Vieira, Joseli

2003-01-01

Immunization of BALB/c mice with an expression genomic library of Toxoplasma gondii induces a Th1-type immune response, with recognition of several T. gondii proteins (21 to 117 kDa) and long-term protective immunity against a lethal challenge. These results support further investigations to achieve a multicomponent anti-T. gondii DNA vaccine.

Immunization with LJM11 salivary protein protects against infection with Leishmania braziliensis in the presence of Lutzomyia longipalpis saliva.

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Cunha, Jurema M; Abbehusen, Melissa; Suarez, Martha; Valenzuela, Jesus; Teixeira, Clarissa R; Brodskyn, Cláudia I

2018-01-01

Leishmania is transmitted in the presence of sand fly saliva. Protective immunity generated by saliva has encouraged identification of a vector salivary-based vaccine. Previous studies have shown that immunization with LJM11, a salivary protein from Lutzomyia longipalpis, is able to induce a Th1 immune response and protect mice against bites of Leishmania major-infected Lutzomyia longipalpis. Here, we further investigate if immunization with LJM11 recombinant protein is able to confer cross-protection against infection with Leishmania braziliensis associated with salivary gland sonicate (SGS) from Lutzomyia intermedia or Lu. longipalpis. Mice immunized with LJM11 protein exhibited an increased production of anti-LJM11 IgG, IgG1 and IgG2a and a DTH response characterized by an inflammatory infiltrate with the presence of CD4 + IFN-γ + T cells. LJM11-immunized mice were intradermally infected in the ear with L. braziliensis in the presence of Lu. longipalpis or Lu. intermedia SGS. A significant reduction of parasite numbers in the ear and lymph node in the group challenged with L. braziliensis plus Lu. longipalpis SGS was observed, but not when the challenge was performed with L. braziliensis plus Lu. intermedia SGS. A higher specific production of IFN-γ and absence of IL-10 by lymph node cells were only observed in LJM11 immunized mice after infection. After two weeks, a similar frequency of CD4 + IFN-γ + T cells was detected in LJM11 and BSA groups challenged with L. braziliensis plus Lu. longipalpis SGS, suggesting that early events possibly triggered by immunization are essential for protection against Leishmania infection. Our findings support the specificity of saliva-mediated immune responses and reinforce the importance of identifying cross-protective salivary antigens. Copyright © 2017 Elsevier B.V. All rights reserved.

An attenuated Shigella mutant lacking the RNA-binding protein Hfq provides cross-protection against Shigella strains of broad serotype.

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Mitobe, Jiro; Sinha, Ritam; Mitra, Soma; Nag, Dhrubajyoti; Saito, Noriko; Shimuta, Ken; Koizumi, Nobuo; Koley, Hemanta

2017-07-01

Few live attenuated vaccines protect against multiple serotypes of bacterial pathogen because host serotype-specific immune responses are limited to the serotype present in the vaccine strain. Here, immunization with a mutant of Shigella flexneri 2a protected guinea pigs against subsequent infection by S. dysenteriae type 1 and S. sonnei strains. This deletion mutant lacked the RNA-binding protein Hfq leading to increased expression of the type III secretion system via loss of regulation, resulting in attenuation of cell viability through repression of stress response sigma factors. Such increased antigen production and simultaneous attenuation were expected to elicit protective immunity against Shigella strains of heterologous serotypes. Thus, the vaccine potential of this mutant was tested in two guinea pig models of shigellosis. Animals vaccinated in the left eye showed fewer symptoms upon subsequent challenge via the right eye, and even survived subsequent intestinal challenge. In addition, oral vaccination effectively induced production of immunoglobulins without severe side effects, again protecting all animals against subsequent intestinal challenge with S. dysenteriae type 1 or S. sonnei strains. Antibodies against common virulence proteins and the O-antigen of S. flexneri 2a were detected by immunofluorescence microscopy. Reaction of antibodies with various strains, including enteroinvasive Escherichia coli, suggested that common virulence proteins induced protective immunity against a range of serotypes. Therefore, vaccination is expected to cover not only the most prevalent serotypes of S. sonnei and S. flexneri 2a, but also various Shigella strains, including S. dysenteriae type 1, which produces Shiga toxin.

An attenuated Shigella mutant lacking the RNA-binding protein Hfq provides cross-protection against Shigella strains of broad serotype.

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Jiro Mitobe

2017-07-01

Full Text Available Few live attenuated vaccines protect against multiple serotypes of bacterial pathogen because host serotype-specific immune responses are limited to the serotype present in the vaccine strain. Here, immunization with a mutant of Shigella flexneri 2a protected guinea pigs against subsequent infection by S. dysenteriae type 1 and S. sonnei strains. This deletion mutant lacked the RNA-binding protein Hfq leading to increased expression of the type III secretion system via loss of regulation, resulting in attenuation of cell viability through repression of stress response sigma factors. Such increased antigen production and simultaneous attenuation were expected to elicit protective immunity against Shigella strains of heterologous serotypes. Thus, the vaccine potential of this mutant was tested in two guinea pig models of shigellosis. Animals vaccinated in the left eye showed fewer symptoms upon subsequent challenge via the right eye, and even survived subsequent intestinal challenge. In addition, oral vaccination effectively induced production of immunoglobulins without severe side effects, again protecting all animals against subsequent intestinal challenge with S. dysenteriae type 1 or S. sonnei strains. Antibodies against common virulence proteins and the O-antigen of S. flexneri 2a were detected by immunofluorescence microscopy. Reaction of antibodies with various strains, including enteroinvasive Escherichia coli, suggested that common virulence proteins induced protective immunity against a range of serotypes. Therefore, vaccination is expected to cover not only the most prevalent serotypes of S. sonnei and S. flexneri 2a, but also various Shigella strains, including S. dysenteriae type 1, which produces Shiga toxin.

Studies on the protection effects of functional foods for skin immune system from radiation damage

Energy Technology Data Exchange (ETDEWEB)

Yee, Sung Tae; Shin, Seong Hae; Kim, Do Sun; Heo, Ji Yun; Kang, Hye In [Sunchon National University, Sunchon (Korea, Republic of)

2007-07-15

We evaluated the protective effects of pilot products (HemoHIM and HemoTonic) on the UV-induced skin immune damages as the following. centre dot Protective effects of HemoHIM and HemoTonic against UV using contact hypersensitivity model - Protection against depression of contact hypersensitivity by administration and skin application of HemoHIM and HemoTonic - Induction of dendritic cell differentiation and maturation by HemoHIM and HemoTonic treatment - Improvement of antigen-presenting activity of dedritic cells by HemoHIM and HemoTonic treatment centre dot Protective effects of HemoHIM and HemoTonic on skin immune system against UV-irradiation - Protection of antigen-presenting activity of dendritic cells under UV-irradiation - In vivo protection of antigen-presenting activity of Langerhans cells in UV-irradiated mice centre dot Protective effects of HemoHIM on UV-induced apoptosis of dendritic cells - Inhibition of cell membrane change, mitochondrial potential change, SubG1 cell population, nuclear condensation, and DNA fragmentation in UV-irradiated dendritic cells centre dot Anti-allergic effects of HemoHIM and HemoTonic in human adipocyte HMC-1 cells - Inhibition of allergic histamine release from adipocytes - Inhibition of secretion of inflammatory cytokines (IL-6, IL-8, TNF-alpha, GM-CSF) - Inhibition of c-kit, tryptase, FcepsilonRI mRNA expression From these results, the developed functional food products (HemoHIM, HemoTonic) showed the protection and recovery of the immune functions in the UV-irradiated skin. It is suggested that these products may be used as a new functional food or cosmetic material for the protection of skin damage and the promotion of recovery

Protection against avian metapneumovirus subtype C in turkeys immunized via the respiratory tract with inactivated virus.

Science.gov (United States)

Cha, Ra Mi; Khatri, Mahesh; Sharma, Jagdev M

2011-01-10

Avian metapneumovirus subtype C (aMPV/C) causes a severe upper respiratory tract (URT) infection in turkeys. Turkeys were inoculated oculonasally with inactivated aMPV/C adjuvanted with synthetic double-stranded RNA polyriboinosinic polyribocytidylic acid (Poly IC). Immunized turkeys had elevated numbers of mucosal IgA+ cells in the URT and increased levels of virus-specific IgG and IgA in the lachrymal fluid and IgG in the serum. After 7 or 21 days post immunization, turkeys were challenged oculonasally with pathogenic aMPV/C. Immunized groups were protected against respiratory lesions induced by the challenge virus. Further, the viral copy number of the challenge virus in the URT were significantly lower in the immunized turkeys than in the unimmunized turkeys (P<0.05). These results showed that inactivated aMPV/C administered by the respiratory route induced protective immunity against pathogenic virus challenge. Copyright © 2010 Elsevier Ltd. All rights reserved.

Downmodulation of Vaccine-Induced Immunity and Protection against the Intracellular Bacterium Francisella tularensis by the Inhibitory Receptor FcγRIIB

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Brian J. Franz

2015-01-01

Full Text Available Fc gamma receptor IIB (FcγRIIB is the only Fc gamma receptor (FcγR which negatively regulates the immune response, when engaged by antigen- (Ag- antibody (Ab complexes. Thus, the generation of Ag-specific IgG in response to infection or immunization has the potential to downmodulate immune protection against infection. Therefore, we sought to determine the impact of FcγRIIB on immune protection against Francisella tularensis (Ft, a Category A biothreat agent. We utilized inactivated Ft (iFt as an immunogen. Naïve and iFt-immunized FcγRIIB knockout (KO or wildtype (WT mice were challenged with Ft-live vaccine strain (LVS. While no significant difference in survival between naïve FcγRIIB KO versus WT mice was observed, iFt-immunized FcγRIIB KO mice were significantly better protected than iFt-immunized WT mice. Ft-specific IgA in serum and bronchial alveolar lavage, as well as IFN-γ, IL-10, and TNF-α production by splenocytes harvested from iFt-immunized FcγRIIB KO, were also significantly elevated. In addition, iFt-immunized FcγRIIB KO mice exhibited a reduction in proinflammatory cytokine levels in vivo at 5 days after challenge, which correlates with increased survival following Ft-LVS challenge in published studies. Thus, these studies demonstrate for the first time the ability of FcγRIIB to regulate vaccine-induced IgA production and downmodulate immunity and protection. The immune mechanisms behind the above observations and their potential impact on vaccine development are discussed.

Immunization with Tc52 or its amino terminal domain adjuvanted with c-di-AMP induces Th17+Th1 specific immune responses and confers protection against Trypanosoma cruzi.

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Marina N Matos

2017-02-01

Full Text Available The development of new adjuvants enables fine modulation of the elicited immune responses. Ideally, the use of one or more adjuvants should result in the induction of a protective immune response against the specific pathogen. We have evaluated the immune response and protection against Trypanosoma cruzi infection in mice vaccinated with recombinant Tc52 or its N- and C-terminal domains (NTc52 and CTc52 adjuvanted either with the STING (Stimulator of Interferon Genes agonist cyclic di-AMP (c-di-AMP, a pegylated derivative of α-galactosylceramide (αGC-PEG, or oligodeoxynucleotides containing unmethylated CpG motifs (ODN-CpG. All groups immunized with the recombinant proteins plus adjuvant: Tc52+c-di-AMP, NTc52+c-di-AMP, CTc52+c-di-AMP, NTc52+c-di-AMP+αGC-PEG, NTc52+CpG, developed significantly higher anti-Tc52 IgG titers than controls. Groups immunized with c-di-AMP and Tc52, NTc52 or CTc52 showed the highest Tc52-specific IgA titers in nasal lavages. All groups immunized with the recombinant proteins plus adjuvant developed a strong specific cellular immune response in splenocytes and lymph node cells with significant differences for groups immunized with c-di-AMP and Tc52, NTc52 or CTc52. These groups also showed high levels of Tc52-specific IL-17 and IFN-γ producing cells, while NTc52+CpG group only showed significant difference with control in IFN-γ producing cells. Groups immunized with c-di-AMP and Tc52, NTc52 or CTc52 developed predominantly a Th17 and Th1immune response, whereas for NTc52+CpG it was a dominant Th1 response. It was previously described that αGC-PEG inhibits Th17 differentiation by activating NKT cells. Thus, in this work we have also included a group immunized with both adjuvants (NTc52+c-di-AMP+αGC-PEG with the aim to modulate the Th17 response induced by c-di-AMP. This group showed a significant reduction in the number of Tc52-specific IL-17 producing splenocytes, as compared to the group NTc52+c-di-AMP, which has

The specificity of immune priming in silkworm, Bombyx mori, is mediated by the phagocytic ability of granular cells.

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Wu, Gongqing; Li, Mei; Liu, Yi; Ding, Ying; Yi, Yunhong

2015-10-01

In the past decade, the phenomenon of immune priming was documented in many invertebrates in a large number of studies; however, in most of these studies, behavioral evidence was used to identify the immune priming. The underlying mechanism and the degree of specificity of the priming response remain unclear. We studied the mechanism of immune priming in the larvae of the silkworm, Bombyx mori, and analyzed the specificity of the priming response using two closely related Gram-negative pathogenic bacteria (Photorhabdus luminescens TT01 and P. luminescens H06) and one Gram-positive pathogenic bacterium (Bacillus thuringiensis HD-1). Primed with heat-killed bacteria, the B. mori larvae were more likely to survive subsequent homologous exposure (the identical bacteria used in the priming and in the subsequent challenge) than heterologous (different bacteria used in the priming and subsequent exposure) exposure to live bacteria. This result indicated that the B. mori larvae possessed a strong immune priming response and revealed a degree of specificity to TT01, H06 and HD-1 bacteria. The degree of enhanced immune protection was positively correlated with the level of phagocytic ability of the granular cells and the antibacterial activity of the cell-free hemolymph. Moreover, the granular cells of the immune-primed larvae increased the phagocytosis of a previously encountered bacterial strain compared with other bacteria. Thus, the enhanced immune protection of the B. mori larvae after priming was mediated by the phagocytic ability of the granular cells and the antibacterial activity of the hemolymph; the specificity of the priming response was primarily attributed to the phagocytosis of bacteria by the granular cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

MUC16 provides immune protection by inhibiting synapse formation between NK and ovarian tumor cells

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Migneault Martine

2010-01-01

Full Text Available Abstract Background Cancer cells utilize a variety of mechanisms to evade immune detection and attack. Effective immune detection largely relies on the formation of an immune synapse which requires close contact between immune cells and their targets. Here, we show that MUC16, a heavily glycosylated 3-5 million Da mucin expressed on the surface of ovarian tumor cells, inhibits the formation of immune synapses between NK cells and ovarian tumor targets. Our results indicate that MUC16-mediated inhibition of immune synapse formation is an effective mechanism employed by ovarian tumors to evade immune recognition. Results Expression of low levels of MUC16 strongly correlated with an increased number of conjugates and activating immune synapses between ovarian tumor cells and primary naïve NK cells. MUC16-knockdown ovarian tumor cells were more susceptible to lysis by primary NK cells than MUC16 expressing controls. This increased lysis was not due to differences in the expression levels of the ligands for the activating receptors DNAM-1 and NKG2D. The NK cell leukemia cell line (NKL, which does not express KIRs but are positive for DNAM-1 and NKG2D, also conjugated and lysed MUC16-knockdown cells more efficiently than MUC16 expressing controls. Tumor cells that survived the NKL challenge expressed higher levels of MUC16 indicating selective lysis of MUC16low targets. The higher csMUC16 levels on the NKL resistant tumor cells correlated with more protection from lysis as compared to target cells that were never exposed to the effectors. Conclusion MUC16, a carrier of the tumor marker CA125, has previously been shown to facilitate ovarian tumor metastasis and inhibits NK cell mediated lysis of tumor targets. Our data now demonstrates that MUC16 expressing ovarian cancer cells are protected from recognition by NK cells. The immune protection provided by MUC16 may lead to selective survival of ovarian cancer cells that are more efficient in

Evaluation of the protection induced by the immunization with radioiodinated yeast cells of Paracoccidioides brasiliensis in animal model

International Nuclear Information System (INIS)

Martins, Estefania Mara do Nascimento

2007-01-01

Paracoccidioides brasiliensis is fungus agent of paracoccidioidomycosis (PCM), a chronic systemic disease prevalent in Latin American. To date, there is no effective vaccine. The potential of gamma radiation for pathogens attenuation and vaccine development was explored in this work. In our laboratory were developed yeast cells of P. brasiliensis attenuated by gamma radiation, which lose the reproductive ability, while retaining the morphology, the synthesis and secretion of proteins, the oxidative metabolism and the expression of the antigens present in the native yeast. The aim of the present work was to evaluate the protection elicited by the immunization with this cells in animal model. The virulence attenuated was evaluated in BALB/c and Nude-Nude mice. The protector effect was evaluated in BALB/c mice groups immunized once or twice. Each group was divided in three sub groups that were challenge 30, 45 or 60 days after the immunization. The mice were sacrificed 30 and 90 days after challenge. The removed organs were used for colony forming units (CFU's) recover, histopathological analysis and cytokine determination. The sera were collected weekly to evaluate the IgG antibody titers and the IgG1 and IgG2a pattern in the course of infection. To evaluate the type of elicited immune response the cytokines IFN - γ, TNF - α, IL - 10 and IL - 5 were determined by real time PCR. The radio attenuated yeast loses its virulence since fails in producing infection in BALB/c and Nude-Nude mice. No CFU's were recovered neither histological changes observed in the mice infected with the radio attenuated cells. The mice infected with the not irradiated P. brasiliensis showed a high level of antibody production while the infection with the radio attenuated yeast did not significantly change the antibody level. The mice infected with the radio attenuated yeast presented an increase in the IFN - γ and TNF - α production and an inhibition of the IL-10 synthesis, indicating a

Association of the Host Immune Response with Protection Using a Live Attenuated African Swine Fever Virus Model

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Jolene Carlson

2016-10-01

Full Text Available African swine fever (ASF is a lethal hemorrhagic disease of swine caused by a double-stranded DNA virus, ASF virus (ASFV. There is no vaccine to prevent the disease and current control measures are limited to culling and restricting animal movement. Swine infected with attenuated strains are protected against challenge with a homologous virulent virus, but there is limited knowledge of the host immune mechanisms generating that protection. Swine infected with Pretoriuskop/96/4 (Pret4 virus develop a fatal severe disease, while a derivative strain lacking virulence-associated gene 9GL (Pret4Δ9GL virus is completely attenuated. Swine infected with Pret4Δ9GL virus and challenged with the virulent parental virus at 7, 10, 14, 21, and 28 days post infection (dpi showed a progressive acquisition of protection (from 40% at 7 dpi to 80% at 21 and 28 dpi. This animal model was used to associate the presence of host immune response (ASFV-specific antibody and interferon (IFN-γ responses, or specific cytokine profiles and protection against challenge. With the exception of ASFV-specific antibodies in survivors challenged at 21 and 28 dpi, no association between the parameters assessed and protection could be established. These results, encompassing data from 65 immunized swine, underscore the complexity of the system under study, suggesting that protection relies on the concurrence of different host immune mechanisms.

Heterologous prime-boost strategy in non-human primates combining the infective dengue virus and a recombinant protein in a formulation suitable for human use.

Science.gov (United States)

Valdés, Iris; Hermida, Lisset; Gil, Lázaro; Lazo, Laura; Castro, Jorge; Martín, Jorge; Bernardo, Lídice; López, Carlos; Niebla, Olivia; Menéndez, Tamara; Romero, Yaremis; Sánchez, Jorge; Guzmán, María G; Guillén, Gerardo

2010-05-01

The aim of the present work was to test the concept of the heterologous prime-boost strategy combining an infective dengue virus with a recombinant chimeric protein carrying domain III of the envelope protein. Two studies in monkeys, combining recombinant protein PD5 (domain III of the envelope protein from dengue-2 virus, fused to the protein carrier P64k) and the infective dengue virus in the same immunization schedules were carried out. Humoral and cell-mediated immunity were evaluated. In the first study, monkeys received four doses of the protein PD5 and were subsequently infected with one dose of dengue virus. Antibody response measured after virus inoculation was significantly higher compared to that in non-primed monkeys and comparable to that elicited after two doses of infective virus. In a second study, monkeys were infected with one dose of the virus and subsequently boosted with one dose of the recombinant protein, reaching high levels of neutralizing antibodies, which were still detectable 14 months after the last immunization. In addition, the cellular immune response was also recalled. The results obtained in the present work support the approach of heterologous prime-boosting, in either order prime or boost, combining the chimeric protein PD5 (formulated in alum-CPS-A) and an infective dengue virus. The latter could potentially be replaced by an attenuated vaccine candidate. Copyright 2009 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Intradermal Immunization of Leishmania donovani Centrin Knock-Out Parasites in Combination with Salivary Protein LJM19 from Sand Fly Vector Induces a Durable Protective Immune Response in Hamsters.

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Jacqueline Araújo Fiuza

2016-01-01

Full Text Available Visceral leishmaniasis (VL is a neglected tropical disease and is fatal if untreated. There is no vaccine available against leishmaniasis. The majority of patients with cutaneous leishmaniasis (CL or VL develop a long-term protective immunity after cure from infection, which indicates that development of an effective vaccine against leishmaniasis is possible. Such protection may also be achieved by immunization with live attenuated parasites that do not cause disease. We have previously reported a protective response in mice, hamsters and dogs with Leishmania donovani centrin gene knock-out parasites (LdCen-/-, a live attenuated parasite with a cell division specific centrin1 gene deletion. In this study we have explored the effects of salivary protein LJM19 as an adjuvant and intradermal (ID route of immunization on the efficacy of LdCen-/- parasites as a vaccine against virulent L. donovani.To explore the potential of a combination of LdCen-/- parasites and salivary protein LJM19 as vaccine antigens, LdCen-/- ID immunization followed by ID challenge with virulent L. donovani were performed in hamsters in a 9-month follow up study. We determined parasite burden (serial dilution, antibody production (ELISA and cytokine expression (qPCR in these animals. Compared to controls, animals immunized with LdCen-/- + LJM19 induced a strong antibody response, a reduction in spleen and liver parasite burden and a higher expression of pro-inflammatory cytokines after immunization and one month post-challenge. Additionally, a low parasite load in lymph nodes, spleen and liver, and a non-inflamed spleen was observed in immunized animals 9 months after the challenge infection.Our results demonstrate that an ID vaccination using LdCen-/-parasites in combination with sand fly salivary protein LJM19 has the capability to confer long lasting protection against visceral leishmaniasis that is comparable to intravenous or intracardial immunization.

Gut symbiotic microbes imprint intestinal immune cells with the innate receptor SLAMF4 which contributes to gut immune protection against enteric pathogens.

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Cabinian, Allison; Sinsimer, Daniel; Tang, May; Jang, Youngsoon; Choi, Bongkum; Laouar, Yasmina; Laouar, Amale

2018-05-01

Interactions between host immune cells and gut microbiota are crucial for the integrity and function of the intestine. How these interactions regulate immune cell responses in the intestine remains a major gap in the field. We have identified the signalling lymphocyte activation molecule family member 4 (SLAMF4) as an immunomodulator of the intestinal immunity. The aim is to determine how SLAMF4 is acquired in the gut and what its contribution to intestinal immunity is. Expression of SLAMF4 was assessed in mice and humans. The mechanism of induction was studied using GFP tg bone marrow chimaera mice, lymphotoxin α and TNLG8A-deficient mice, as well as gnotobiotic mice. Role in immune protection was revealed using oral infection with Listeria monocytogenes and Cytobacter rodentium . SLAMF4 is a selective marker of intestinal immune cells of mice and humans. SLAMF4 induction occurs directly in the intestinal mucosa without the involvement of the gut-associated lymphoid tissue. Gut bacterial products, particularly those of gut anaerobes, and gut-resident antigen-presenting cell (APC) TNLG8A are key contributors of SLAMF4 induction in the intestine. Importantly, lack of SLAMF4 expression leads the increased susceptibility of mice to infection by oral pathogens culminating in their premature death. SLAMF4 is a marker of intestinal immune cells which contributes to the protection against enteric pathogens and whose expression is dependent on the presence of the gut microbiota. This discovery provides a possible mechanism for answering the long-standing question of how the intertwining of the host and gut microbial biology regulates immune cell responses in the gut. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Immune response in bovine neosporosis: Protection or contribution to the pathogenesis of abortion.

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Almería, Sonia; Serrano-Pérez, Beatriz; López-Gatius, Fernando

2017-08-01

Neospora caninum is a protozoan parasite with a preference for cattle and dogs as hosts. When N. caninum infection occurs in cattle it induces abortion, bovine neosporosis being a main cause of abortion worldwide. In dairy cattle, the economic burden of neosporosis-associated abortion is so great that it might results in closure of a farm. However, not all infected cows abort and it is not yet understood why this occurs. At present there is no effective treatment or vaccine. This review provides insights on how immune response against the parasite determines protection or contribution to abortion. Aspects on markers of risk of abortion are also discussed. Humoral immune responses are not protective against N. caninum but seropositivity and antibody level can be good markers for a diagnosis of bovine neosporosis and its associated abortion risk. In addition, humoral mechanisms against N. caninum infection and abortion differ in pure-breed and cross-breed pregnant dairy and beef cattle. Concentrations of Pregnancy Associated glycoprotein -2 (PAG-2) can also be used to predict abortion. A partially protective immune response encompasses increased IFN-γ expression, which has to be counterbalanced by other cytokines such as IL-12 and IL-10, especially towards the end of pregnancy. Although IFN-γ is required to limit parasite proliferation a critical threshold of the IFN-γ response is also required to limit adverse effects on pregnancy. In clinical terms, it may be stated that IFN-γ production and cross-breed pregnancy can protect Neospora-infected dairy cows against abortion. Published by Elsevier Ltd.

Canine Distemper Virus (CDV) immune-stimulating complexes (iscoms), but not measles virus iscoms, protect dogs against CDV infection.

NARCIS (Netherlands)

P. de Vries (Petra); F.G.C.M. Uytdehaag (Fons); A.D.M.E. Osterhaus (Albert)

1988-01-01

textabstractThe potential of immune-stimulating complexes (iscoms), a novel form of antigenic presentation, for the induction of protective immunity against morbillivirus infection was shown by immunizing dogs with canine distemper virus (CDV) iscoms, which contained the fusion (F) protein and a

Phi ({Phi}) and psi ({Psi}) angles involved in malarial peptide bonds determine sterile protective immunity

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Patarroyo, Manuel E., E-mail: mepatarr@gmail.com [Fundacion Instituto de Inmunologia de Colombia (FIDIC), Bogota (Colombia); Universidad Nacional de Colombia, Bogota (Colombia); Moreno-Vranich, Armando; Bermudez, Adriana [Fundacion Instituto de Inmunologia de Colombia (FIDIC), Bogota (Colombia)

2012-12-07

Highlights: Black-Right-Pointing-Pointer Phi ({Phi}) and psi ({Psi}) angles determine sterile protective immunity. Black-Right-Pointing-Pointer Modified peptide's tendency to assume a regular conformation related to a PPII{sub L}. Black-Right-Pointing-Pointer Structural modifications in mHABPs induce Ab and protective immunity. Black-Right-Pointing-Pointer mHABP backbone atom's interaction with HLA-DR{beta}1{sup Asterisk-Operator} is stabilised by H-bonds. -- Abstract: Modified HABP (mHABP) regions interacting with HLA-DR{beta}1{sup Asterisk-Operator} molecules have a more restricted conformation and/or sequence than other mHABPs which do not fit perfectly into their peptide binding regions (PBR) and do not induce an acceptable immune response due to the critical role of their {Phi} and {Psi} torsion angles. These angle's critical role was determined in such highly immunogenic, protection-inducing response against experimental malaria using the conformers (mHABPs) obtained by {sup 1}H-NMR and superimposed into HLA-DR{beta}1{sup Asterisk-Operator }-like Aotus monkey molecules; their phi ({Phi}) and psi ({Psi}) angles were measured and the H-bond formation between these molecules was evaluated. The aforementioned mHABP propensity to assume a regular conformation similar to a left-handed polyproline type II helix (PPII{sub L}) led to suggesting that favouring these conformations according to their amino acid sequence would lead to high antibody titre production and sterile protective immunity induction against malaria, thereby adding new principles or rules for vaccine development, malaria being one of them.

Vaccine protection of chickens against antigenically diverse H5 highly pathogenic avian influenza isolates with a live HVT vector vaccine expressing the influenza hemagglutinin gene derived from a clade 2.2 avian influenza virus.

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Kapczynski, Darrell R; Esaki, Motoyuki; Dorsey, Kristi M; Jiang, Haijun; Jackwood, Mark; Moraes, Mauro; Gardin, Yannick

2015-02-25

Vaccination is an important tool in the protection of poultry against avian influenza (AI). For field use, the overwhelming majority of AI vaccines produced are inactivated whole virus formulated into an oil emulsion. However, recombinant vectored vaccines are gaining use for their ability to induce protection against heterologous isolates and ability to overcome maternal antibody interference. In these studies, we compared protection of chickens provided by a turkey herpesvirus (HVT) vector vaccine expressing the hemagglutinin (HA) gene from a clade 2.2 H5N1 strain (A/swan/Hungary/4999/2006) against homologous H5N1 as well as heterologous H5N1 and H5N2 highly pathogenic (HP) AI challenge. The results demonstrated all vaccinated birds were protected from clinical signs of disease and mortality following homologous challenge. In addition, oral and cloacal swabs taken from challenged birds demonstrated that vaccinated birds had lower incidence and titers of viral shedding compared to sham-vaccinated birds. Following heterologous H5N1 or H5N2 HPAI challenge, 80-95% of birds receiving the HVT vector AI vaccine at day of age survived challenge with fewer birds shedding virus after challenge than sham vaccinated birds. In vitro cytotoxicity analysis demonstrated that splenic T lymphocytes from HVT-vector-AI vaccinated chickens recognized MHC-matched target cells infected with H5, as well as H6, H7, or H9 AI virus. Taken together, these studies provide support for the use of HVT vector vaccines expressing HA to protect poultry against multiple lineages of HPAI, and that both humoral and cellular immunity induced by live vaccines likely contributes to protection. Published by Elsevier Ltd.

Mechanisms of stage-transcending protection following immunization of mice with late liver stage-arresting genetically attenuated malaria parasites.

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Brandon K Sack

2015-05-01

Full Text Available Malaria, caused by Plasmodium parasite infection, continues to be one of the leading causes of worldwide morbidity and mortality. Development of an effective vaccine has been encumbered by the complex life cycle of the parasite that has distinct pre-erythrocytic and erythrocytic stages of infection in the mammalian host. Historically, malaria vaccine development efforts have targeted each stage in isolation. An ideal vaccine, however, would target multiple life cycle stages with multiple arms of the immune system and be capable of eliminating initial infection in the liver, the subsequent blood stage infection, and would prevent further parasite transmission. We have previously shown that immunization of mice with Plasmodium yoelii genetically attenuated parasites (GAP that arrest late in liver stage development elicits stage-transcending protection against both a sporozoite challenge and a direct blood stage challenge. Here, we show that this immunization strategy engenders both T- and B-cell responses that are essential for stage-transcending protection, but the relative importance of each is determined by the host genetic background. Furthermore, potent anti-blood stage antibodies elicited after GAP immunization rely heavily on FC-mediated functions including complement fixation and FC receptor binding. These protective antibodies recognize the merozoite surface but do not appear to recognize the immunodominant merozoite surface protein-1. The antigen(s targeted by stage-transcending immunity are present in both the late liver stages and blood stage parasites. The data clearly show that GAP-engendered protective immune responses can target shared antigens of pre-erythrocytic and erythrocytic parasite life cycle stages. As such, this model constitutes a powerful tool to identify novel, protective and stage-transcending T and B cell targets for incorporation into a multi-stage subunit vaccine.

Can VHS Virus Bypass the Protective Immunity Induced by DNA Vaccination in Rainbow Trout?

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Dagoberto Sepúlveda

Full Text Available DNA vaccines encoding viral glycoproteins have been very successful for induction of protective immunity against diseases caused by rhabdoviruses in cultured fish species. However, the vaccine concept is based on a single viral gene and since RNA viruses are known to possess high variability and adaptation capacity, this work aimed at evaluating whether viral haemorrhagic septicaemia virus (VHSV, an RNA virus and member of Rhabdoviridae family, was able to evade the protective immune response induced by the DNA vaccination of rainbow trout. The experiments comprised repeated passages of a highly pathogenic VHSV isolate in a fish cell line in the presence of neutralizing fish serum (in vitro approach, and in rainbow trout immunized with the VHS DNA vaccine (in vivo approach. For the in vitro approach, the virus collected from the last passage (passaged virus was as sensitive as the parental virus to serum neutralization, suggesting that the passaging did not promote the selection of virus populations able to bypass the neutralization by serum antibodies. Also, in the in vivo approach, where virus was passaged several times in vaccinated fish, no increased virulence nor increased persistence in vaccinated fish was observed in comparison with the parental virus. However, some of the vaccinated fish did get infected and could transmit the infection to naïve cohabitant fish. The results demonstrated that the DNA vaccine induced a robust protection, but also that the immunity was non-sterile. It is consequently important not to consider vaccinated fish as virus free in veterinary terms.

Low doses of flagellin-L2 multimer vaccines protect against challenge with diverse papillomavirus genotypes.

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Kalnin, Kirill; Tibbitts, Timothy; Yan, Yanhua; Stegalkina, Svetlana; Shen, Lihua; Costa, Victor; Sabharwal, Robert; Anderson, Stephen F; Day, Patricia M; Christensen, Neil; Schiller, John T; Jagu, Subhashini; Roden, Richard B S; Almond, Jeffrey; Kleanthous, Harold

2014-06-12

Genetically modified bacterial flagellin (Fla), a Toll-like receptor-5 (TLR5) ligand, was evaluated as a fusion partner for human papillomavirus (HPV) L2-based immunogens in two animal challenge models; either cutaneous inoculation of rabbits with HPV 'quasivirions' containing cottontail rabbit papillomavirus (CRPV) genomes that induce warts, or intra-vaginal inoculation of mice with HPV 'pseudovirions' encapsidating a luciferase reporter plasmid and measurement of bioluminescence to determine infectivity. An Escherichia coli production system was developed for flagellin-L2 (Fla-L2) fusions containing either monomeric HPV-16 L2 a.a. 11(×11-200) or oligomeric L2 comprising a fusion of the a.a. 11-88 peptides of five (Fla∼5×11-88) or eight (Fla∼8×11-88) genital HPV types. Immunogenicity and bioactivity of Fla-L2 constructs were assessed using an in vitro neutralization and cell-based TLR-5 binding assay, respectively. Efficacy was evaluated following active immunization of rabbits or mice administered 3 intramuscular doses of Fla-L2 recombinants without exogenous adjuvant, followed by challenge. In addition, passive immunization studies of naïve rabbits with serial dilutions of pooled immune sera were used to determine End-Point Protection Titers (EPPT) for each formulation against a broader spectrum of HPV quasivirions. Efficacy was assessed for up to 10 weeks on the basis of wart volume induced following challenge and results compared to licensed L1-VLP vaccines (Gardasil and Cervarix). Following active immunization at doses as low as 1 μg, Fla-L2 fusions afforded complete protection against infection (mice) and disease (rabbits) following either homologous or heterologous HPV challenge. Passive immunization with anti-L2 immune sera discriminated between the different vaccine candidates under evaluation, demonstrated the protective role of antibody and suggested the superiority of this oligomeric L2-TLR5 agonist fusion approach compared to L1-based

Protective immune responses with trickle infections of third-stage filarial larvae of Wuchereria bancrofti in mice.

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Rajasekariah, G R; Monteiro, Y M; Netto, A; Deshpande, L; Subrahmanyam, D

1989-01-01

Groups of inbred BALB/c mice were immunized with trickle doses of 20 live third-stage larvae (L3) of Wuchereria bancrofti each subcutaneously or with 150 microg of sonicated microfilarial antigens emulsified in Freund's adjuvant intramuscularly. An antibody response was distinctly seen after seven trickle doses of L3 and following with the sonicated microfilarial immunization. Due to the non-permissive nature of inbred mice to W. bancrofti infections, a novel immunization approach was adopted using appropriate age- and sex-matched controls. The anti-L3 response in terms of antibody-dependent cell-mediated adhesion and killing was assessed in the immunized animals by implanting live L3 in micropore chambers subcutaneously. About 75% L3 W. bancrofti were affected in animals sensitized with seven trickle doses of L3. When sensitizations were continued, as high as 92% of L3 were seen affected with ten trickle doses compared with 27% in age-matched controls. Immunization with sonicated microfilarial antigen affected about 70% of L3 as opposed to only 12% in controls. A positive correlation was observed in the antibody response with protectivity. This method of induction and assessment of the anti-L3 response involving a small set of animals has not only allowed quantification of affected L3 but has also enabled us to visualize larval conditions in immunologically activated animals. The micropore chamber system, would be useful in monitoring the induction of protective immune response against W. bancrofti in inbred mice. Experimentation on large numbers of animals is required to elucidate further the response of mice towards L3 and also to pinpoint the putative protective antigens. PMID:12412764

Prime immunization with rotavirus VLP 2/6 followed by boosting with an adenovirus expressing VP6 induces protective immunization against rotavirus in mice

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Qu Jianguo

2011-01-01

Full Text Available Abstract Background Rotavirus (RV is the main cause of severe gastroenteritis in children. An effective vaccination regime against RV can substantially reduce morbidity and mortality. Previous studies have demonstrated the efficacy of virus-like particles formed by RV VP2 and VP6 (VLP2/6, as well as that of recombinant adenovirus expressing RV VP6 (rAd, in eliciting protective immunities against RV. However, the efficacy of such prime-boost strategy, which incorporates VLP and rAd in inducing protective immunities against RV, has not been addressed. We assessed the immune effects of different regimens in mice, including rAd prime-VLP2/6 boost (rAd+VLP, VLP2/6 prime-rAd boost (VLP+rAd, rAd alone, and VLP alone. Results Mice immunized with the VLP+rAd regimen elicit stronger humoral, mucosal, and cellular immune responses than those immunized with other regimens. RV challenging experiments showed that the highest reduction (92.9% in viral shedding was achieved in the VLP+rAd group when compared with rAd+VLP (25%, VLP alone (75%, or rAd alone (40% treatment groups. The reduction in RV shedding in mice correlated with fecal IgG (r = 0.95773, P = 0.04227 and IgA (r = 0.96137, P = 0.038663. Conclusions A VLP2/6 prime-rAd boost regimen is effective in conferring immunoprotection against RV challenge in mice. This finding may lay the groundwork for an alternative strategy in novel RV vaccine development.

Effects of anti-schistosomal chemotherapy on immune responses, protection and immunity. II. Concomitant immunity and immunization with irradiated cercariae

International Nuclear Information System (INIS)

Tawfik, A.F.; Colley, D.G.

1986-01-01

Resistance of mice to challenge infections of Schistosoma mansoni was evaluated before and after elimination of their primary, established S. mansoni infections with the chemotherapeutic drug praziquantel. Mice treated after either 10 or 20 weeks of primary infection were challenged 6 or 10 weeks after treatment. Mice infected for for 10 weeks prior to treatment expressed progressively less resistance 6 and 10 weeks after treatment. By 10 weeks after treatment significant levels of protection were no longer observed. Resistance waned more slowly if mice were treated 20 weeks after infection, and there was still significant expression of resistance to challenge 10 weeks after treatment. A separate set of experiments evaluated the use of highly irradiated cercariae as a vaccine in mice that had been previously infected with S. mansoni and cured with praziquantel. It was observed that effective immunizations were possible in previously infected mice. These studies demonstrate that established resistance waned after treatment and the rate of loss of protection was dependent upon the duration of infection prior to treatment. Furthermore, the irradiated cercarial vaccine studies indicate that in the murine model induction of immunological resistance was feasible following chemotherapeutic treatment of infected populations

Use of a Vaccinia Construct Expressing the Circumsporozoite Protein in the Analysis of Protective Immunity to Plasmodium yoelii

Science.gov (United States)

1988-01-01

William R. Majarian, 2 ,5 Frank A. Robey, 3 Walter Weiss, 1 and Stephen L. Hoffman 1 lInfectious Diseases Department, Naval Medical Research Institute...autoradiography. Recombinant viruses which were positive in this assay were subject to 3 rounds of plaque purification. Finally, plaque purified virus was...mechanisms in the protective immunity elicited by inmunization with irradiated sporozoites (3,7,8,9). In an attempt to induce a protective cellular immune

Sporothrix schenckii Immunization, but Not Infection, Induces Protective Th17 Responses Mediated by Circulating Memory CD4+ T Cells

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Alberto García-Lozano

2018-06-01

Full Text Available Sporotrichosis is a chronic subcutaneous mycosis caused by the Sporothrix schenckii species complex and it is considered an emerging opportunistic infection in countries with tropical and subtropical climates. The host’s immune response has a main role in the development of this disease. However, it is unknown the features of the memory cellular immune response that could protect against the infection. Our results show that i.d. immunization in the ears of mice with inactivated S. schenckii conidia (iC combined with the cholera toxin (CT induces a cellular immune response mediated by circulating memory CD4+ T cells, which mainly produce interleukin 17 (IL-17. These cells mediate a strong delayed-type hypersensitivity (DTH reaction. Systemic and local protection against S. schenckii was mediated by circulating CD4+ T cells. In contrast, the infection induces a potent immune response in the skin mediated by CD4+ T cells, which have an effector phenotype that preferentially produce interferon gamma (IFN-γ and mediate a transitory DTH reaction. Our findings prove the potential value of the CT as a potent skin adjuvant when combined with fungal antigens, and they also have important implications for our better understanding of the differences between the memory immune response induced by the skin immunization and those induced by the infection; this knowledge enhances our understanding of how a protective immune response against a S. schenckii infection is developed.

Brucella lipopolysaccharide reinforced Salmonella delivering Brucella immunogens protects mice against virulent challenge.

Science.gov (United States)

Lalsiamthara, Jonathan; Lee, John Hwa

2017-06-01

Intracellular pathogen Salmonella exhibits natural infection broadly analogous to Brucella, this phenomenon makes Salmonella a pragmatic choice for an anti-Brucella vaccine delivery platform. In this study we developed and formulated a combination of four attenuated Salmonella Typhimurium live vector strains delivering heterologous Brucella antigens (rBs), namely lumazine synthase, proline racemase subunit A, lipoprotein outer membrane protein-19, and Cu-Zn superoxide dismutase. With an aim to develop a cross-protecting vaccine, Brucella pan-species conserved rBs were selected. The present study compared the efficacy of smooth and rough variants of Salmonella delivery vector and also evaluated the inclusion of purified Brucella lipopolysaccharide (LPS) in the formulation. Immunization of SPF-BALB/c mice with the vaccine combinations significantly (P≤0.05) reduced splenic wild-type Brucella abortus 544 colonization as compared to non-immunized mice as well as Salmonella only immunized mice. Increased induction of Brucella specific-IgG, sIgA production, and antigen-specific splenocyte proliferative responses were observed in the mice immunized with the formulations as compared to naïve or vector only immunized mice. Modulatory effects of rB and LPS on production of interleukin (IL)-4, IL-12, and interferon-γ were detected in splenocytes of mice immunized with the formulation. Rough Salmonella variant in combination with LPS could further enhance the efficacy of the delivery when applied intraperitoneally. Taken together, it is compelling that Brucella LPS-augmented Salmonella vector delivering immunogenic Brucella proteins may be more suitable than the current non-ideal live Brucella abortus vaccine. The vaccine system also provides a basis for the development of cross-protecting vaccine capable of preventing multispecies brucellosis. Copyright © 2017 Elsevier B.V. All rights reserved.

New Orf virus (Parapoxvirus) recombinant expressing H5 hemagglutinin protects mice against H5N1 and H1N1 influenza A virus.

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Rohde, Jörg; Amann, Ralf; Rziha, Hanns-Joachim

2013-01-01

Previously we demonstrated the versatile utility of the Parapoxvirus Orf virus (ORFV) as a vector platform for the development of potent recombinant vaccines. In this study we present the generation of new ORFV recombinants expressing the hemagglutinin (HA) or nucleoprotein (NP) of the highly pathogenic avian influenza virus (HPAIV) H5N1. Correct foreign gene expression was examined in vitro by immunofluorescence, Western blotting and flow cytometry. The protective potential of both recombinants was evaluated in the mouse challenge model. Despite adequate expression of NP, the recombinant D1701-V-NPh5 completely failed to protect mice from lethal challenge. However, the H5 HA-expressing recombinant D1701-V-HAh5n mediated solid protection in a dose-dependent manner. Two intramuscular (i.m.) injections of the HA-expressing recombinant protected all animals from lethal HPAIV infection without loss of body weight. Notably, the immunized mice resisted cross-clade H5N1 and heterologous H1N1 (strain PR8) influenza virus challenge. In vivo antibody-mediated depletion of CD4-positive and/or CD8-posititve T-cell subpopulations during immunization and/or challenge infection implicated the relevance of CD4-positive T-cells for induction of protective immunity by D1701-V-HAh5n, whereas the absence of CD8-positive T-cells did not significantly influence protection. In summary, this study validates the potential of the ORFV vectored vaccines also to combat HPAIV.

New Orf virus (Parapoxvirus recombinant expressing H5 hemagglutinin protects mice against H5N1 and H1N1 influenza A virus.

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Jörg Rohde

Full Text Available Previously we demonstrated the versatile utility of the Parapoxvirus Orf virus (ORFV as a vector platform for the development of potent recombinant vaccines. In this study we present the generation of new ORFV recombinants expressing the hemagglutinin (HA or nucleoprotein (NP of the highly pathogenic avian influenza virus (HPAIV H5N1. Correct foreign gene expression was examined in vitro by immunofluorescence, Western blotting and flow cytometry. The protective potential of both recombinants was evaluated in the mouse challenge model. Despite adequate expression of NP, the recombinant D1701-V-NPh5 completely failed to protect mice from lethal challenge. However, the H5 HA-expressing recombinant D1701-V-HAh5n mediated solid protection in a dose-dependent manner. Two intramuscular (i.m. injections of the HA-expressing recombinant protected all animals from lethal HPAIV infection without loss of body weight. Notably, the immunized mice resisted cross-clade H5N1 and heterologous H1N1 (strain PR8 influenza virus challenge. In vivo antibody-mediated depletion of CD4-positive and/or CD8-posititve T-cell subpopulations during immunization and/or challenge infection implicated the relevance of CD4-positive T-cells for induction of protective immunity by D1701-V-HAh5n, whereas the absence of CD8-positive T-cells did not significantly influence protection. In summary, this study validates the potential of the ORFV vectored vaccines also to combat HPAIV.

A genetically engineered live-attenuated simian-human immunodeficiency virus that co-expresses the RANTES gene improves the magnitude of cellular immunity in rhesus macaques

International Nuclear Information System (INIS)

Shimizu, Yuya; Inaba, Katsuhisa; Kaneyasu, Kentaro; Ibuki, Kentaro; Himeno, Ai; Okoba, Masashi; Goto, Yoshitaka; Hayami, Masanori; Miura, Tomoyuki; Haga, Takeshi

2007-01-01

Regulated-on-activation-normal-T-cell-expressed-and-secreted (RANTES), a CC-chemokine, enhances antigen-specific T helper (Th) type-1 responses against HIV-1. To evaluate the adjuvant effects of RANTES against HIV vaccine candidate in SHIV-macaque models, we genetically engineered a live-attenuated SHIV to express the RANTES gene (SHIV-RANTES) and characterized the virus's properties in vivo. After the vaccination, the plasma viral loads were same in the SHIV-RANTES-inoculated monkeys and the parental nef-deleted SHIV (SHIV-NI)-inoculated monkeys. SHIV-RANTES provided some immunity in monkeys by remarkably increasing the antigen-specific CD4 + Th cell-proliferative response and by inducing an antigen-specific IFN-γ ELISpot response. The magnitude of the immunity in SHIV-RANTES-immunized animals, however, failed to afford greater protection against a heterologous pathogenic SHIV (SHIV-C2/1) challenge compared to control SHIV-NI-immunized animals. SHIV-RANTES immunized monkeys, elicited robust cellular CD4 + Th responses and IFN-γ ELISpot responses after SHIV-C2/1 challenge. These findings suggest that the chemokine RANTES can augment vaccine-elicited, HIV-specific CD4 + T cell responses

Protective efficacy of a single immunization with capripoxvirus-vectored recombinant peste des petits ruminants vaccines in presence of pre-existing immunity.

Science.gov (United States)

Caufour, Philippe; Rufael, Tesfaye; Lamien, Charles Euloge; Lancelot, Renaud; Kidane, Menbere; Awel, Dino; Sertse, Tefera; Kwiatek, Olivier; Libeau, Geneviève; Sahle, Mesfin; Diallo, Adama; Albina, Emmanuel

2014-06-24

Sheeppox, goatpox and peste des petits ruminants (PPR) are highly contagious ruminant diseases widely distributed in Africa, the Middle East and Asia. Capripoxvirus (CPV)-vectored recombinant PPR vaccines (rCPV-PPR vaccines), which have been developed and shown to protect against both Capripox (CP) and PPR, would be critical tools in the control of these important diseases. In most parts of the world, these disease distributions overlap each other leaving concerns about the potential impact that pre-existing immunity against either disease may have on the protective efficacy of these bivalent rCPV-PPR vaccines. Currently, this question has not been indisputably addressed. Therefore, we undertook this study, under experimental conditions designed for the context of mass vaccination campaigns of small ruminants, using the two CPV recombinants (Kenya sheep-1 (KS-1) strain-based constructs) developed previously in our laboratory. Pre-existing immunity was first induced by immunization either with an attenuated CPV vaccine strain (KS-1) or the attenuated PPRV vaccine strain (Nigeria 75/1) and animals were thereafter inoculated once subcutaneously with a mixture of CPV recombinants expressing either the hemagglutinin (H) or the fusion (F) protein gene of PPRV (10(3) TCID50/animal of each). Finally, these animals were challenged with a virulent CPV strain followed by a virulent PPRV strain 3 weeks later. Our study demonstrated full protection against CP for vaccinated animals with prior exposure to PPRV and a partial protection against PPR for vaccinated animals with prior exposure to CPV. The latter animals exhibited a mild clinical form of PPR and did not show any post-challenge anamnestic neutralizing antibody response against PPRV. The implications of these results are discussed herein and suggestions made for future research regarding the development of CPV-vectored vaccines. Copyright © 2014 Elsevier Ltd. All rights reserved.

Protection patterns in duck and chicken after homo- or hetero-subtypic reinfections with H5 and H7 low pathogenicity avian influenza viruses: a comparative study.

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Coralie Chaise

Full Text Available Avian influenza viruses are circulating continuously in ducks, inducing a mostly asymptomatic infection, while chickens are accidental hosts highly susceptible to respiratory disease. This discrepancy might be due to a different host response to the virus between these two bird species and in particular to a different susceptibility to reinfection. In an attempt to address this question, we analyzed, in ducks and in chickens, the viral load in infected tissues and the humoral immune response after experimental primary and secondary challenge infections with either homologous or heterologous low pathogenicity avian influenza viruses (LPAIV. Following homologous reinfection, ducks were only partially protected against viral shedding in the lower intestine in conjunction with a moderate antibody response, whereas chickens were totally protected against viral shedding in the upper respiratory airways and developed a stronger antibody response. On the contrary, heterologous reinfection was not followed by a reduced viral excretion in the upper airways of chickens, while ducks were still partially protected from intestinal excretion of the virus, with no correlation to the antibody response. Our comparative study provides a comprehensive demonstration of the variation of viral tropism and control of the host humoral response to LPAIV between two different bird species with different degrees of susceptibility to avian influenza.

Smallpox vaccines: targets of protective immunity.

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Moss, Bernard

2011-01-01

The eradication of smallpox, one of the great triumphs of medicine, was accomplished through the prophylactic administration of live vaccinia virus, a comparatively benign relative of variola virus, the causative agent of smallpox. Nevertheless, recent fears that variola virus may be used as a biological weapon together with the present susceptibility of unimmunized populations have spurred the development of new-generation vaccines that are safer than the original and can be produced by modern methods. Predicting the efficacy of such vaccines in the absence of human smallpox, however, depends on understanding the correlates of protection. This review outlines the biology of poxviruses with particular relevance to vaccine development, describes protein targets of humoral and cellular immunity, compares animal models of orthopoxvirus disease with human smallpox, and considers the status of second- and third-generation smallpox vaccines. Published 2010. This article is a US Government work and is in the public domain in the USA.

Radioimmunoassay with heterologous antibody (hetero-antibody RIA)

International Nuclear Information System (INIS)

Iwasawa, Atsushi; Hayashi, Hiroaki; Itoh, Zen; Wakabayashi, Katsumi

1991-01-01

To develop a homologous radioimmunoassay (RIA) for a hormone of a small or rare animal often meets difficulty in collecting a large amount of purified antigen required for antibody production. On the other hand, to employ a heterologous RIA to estimate the hormone often gives poor sensitivity. To overcome this difficulty, a 'hetero-antibody' RIA was studied. In a hetero-antibody RIA system, a purified preparation of a hormone is used for radioiodination and standardization and a heterologous antibody to the hormone is used for the first antibody. Canine motilin and rat LH were selected as examples, and anti-porcine motilin and anti-hCG, anti-hCGβ or anti-ovine LHβ was used as the heterologous antibody. The sensitivities of the hetero-antibody RIAs were much higher than those of heterologous RIAs in any case, showing that these hetero-antibody RIA systems were suitable for practical use. To clarify the principle of hetero-antibody RIA, antiserum to porcine motilin was fractionated on an affinity column where canine motilin was immobilized. The fraction bound had greater constants of affinity with both porcine and canine motilins than the rest of the antibody fractions. This fraction also reacted with a synthetic peptide corresponding to the C-terminal sequence common to porcine and canine motilins in a competitive binding test with labeled canine motilin. These results suggest that an antibody population having high affinity and cross-reactivity is present in polyclonal antiserum and indicate that the population can be used in hetero-antibody RIA at an appropriate concentration. (author)

Methyltransferase-defective avian metapneumovirus vaccines provide complete protection against challenge with the homologous Colorado strain and the heterologous Minnesota strain.

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Sun, Jing; Wei, Yongwei; Rauf, Abdul; Zhang, Yu; Ma, Yuanmei; Zhang, Xiaodong; Shilo, Konstantin; Yu, Qingzhong; Saif, Y M; Lu, Xingmeng; Yu, Lian; Li, Jianrong

2014-11-01

Avian metapneumovirus (aMPV), also known as avian pneumovirus or turkey rhinotracheitis virus, is the causative agent of turkey rhinotracheitis and is associated with swollen head syndrome in chickens. Since its discovery in the 1970s, aMPV has been recognized as an economically important pathogen in the poultry industry worldwide. The conserved region VI (CR VI) of the large (L) polymerase proteins of paramyxoviruses catalyzes methyltransferase (MTase) activities that typically methylate viral mRNAs at guanine N-7 (G-N-7) and ribose 2'-O positions. In this study, we generated a panel of recombinant aMPV (raMPV) Colorado strains carrying mutations in the S-adenosyl methionine (SAM) binding site in the CR VI of L protein. These recombinant viruses were specifically defective in ribose 2'-O, but not G-N-7 methylation and were genetically stable and highly attenuated in cell culture and viral replication in the upper and lower respiratory tracts of specific-pathogen-free (SPF) young turkeys. Importantly, turkeys vaccinated with these MTase-defective raMPVs triggered a high level of neutralizing antibody and were completely protected from challenge with homologous aMPV Colorado strain and heterologous aMPV Minnesota strain. Collectively, our results indicate (i) that aMPV lacking 2'-O methylation is highly attenuated in vitro and in vivo and (ii) that inhibition of mRNA cap MTase can serve as a novel target to rationally design live attenuated vaccines for aMPV and perhaps other paramyxoviruses. Paramyxoviruses include many economically and agriculturally important viruses such as avian metapneumovirus (aMPV), and Newcastle disease virus (NDV), human pathogens such as human respiratory syncytial virus, human metapneumovirus, human parainfluenza virus type 3, and measles virus, and highly lethal emerging pathogens such as Nipah virus and Hendra virus. For many of them, there is no effective vaccine or antiviral drug. These viruses share common strategies for viral gene

Cold-adapted influenza and recombinant adenovirus vaccines induce cross-protective immunity against pH1N1 challenge in mice.

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Mark R Soboleski

Full Text Available The rapid spread of the 2009 H1N1 pandemic influenza virus (pH1N1 highlighted problems associated with relying on strain-matched vaccines. A lengthy process of strain identification, manufacture, and testing is required for current strain-matched vaccines and delays vaccine availability. Vaccines inducing immunity to conserved viral proteins could be manufactured and tested in advance and provide cross-protection against novel influenza viruses until strain-matched vaccines became available. Here we test two prototype vaccines for cross-protection against the recent pandemic virus.BALB/c and C57BL/6 mice were intranasally immunized with a single dose of cold-adapted (ca influenza viruses from 1977 or recombinant adenoviruses (rAd expressing 1934 nucleoprotein (NP and consensus matrix 2 (M2 (NP+M2-rAd. Antibodies against the M2 ectodomain (M2e were seen in NP+M2-rAd immunized BALB/c but not C57BL/6 mice, and cross-reacted with pH1N1 M2e. The ca-immunized mice did not develop antibodies against M2e. Despite sequence differences between vaccine and challenge virus NP and M2e epitopes, extensive cross-reactivity of lung T cells with pH1N1 peptides was detected following immunization. Both ca and NP+M2-rAd immunization protected BALB/c and C57BL/6 mice against challenge with a mouse-adapted pH1N1 virus.Cross-protective vaccines such as NP+M2-rAd and ca virus are effective against pH1N1 challenge within 3 weeks of immunization. Protection was not dependent on recognition of the highly variable external viral proteins and could be achieved with a single vaccine dose. The rAd vaccine was superior to the ca vaccine by certain measures, justifying continued investigation of this experimental vaccine even though ca vaccine is already available. This study highlights the potential for cross-protective vaccines as a public health option early in an influenza pandemic.

Innate lymphoid cells: models of plasticity for immune homeostasis and rapid responsiveness in protection.

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Almeida, F F; Belz, G T

2016-09-01

Innate lymphoid cells (ILCs) have stormed onto the immune landscape as "newly discovered" cell types. These tissue-resident sentinels are enriched at mucosal surfaces and engage in complex cross talk with elements of the adaptive immune system and microenvironment to orchestrate immune homeostasis. Many parallels exist between innate cells and T cells leading to the initial partitioning of ILCs into rather rigid subsets that reflect their "adaptive-like" effector cytokines profiles. ILCs themselves, however, have unique attributes that are only just beginning to be elucidated. These features result in complementarity with, rather than complete duplication of, functions of the adaptive immune system. Key transcription factors determine the pathway of differentiation of progenitors towards an ILC1, ILC2, or ILC3 subset. Once formed, flexibility in the responses of these subsets to stimuli unexpectedly allows transdifferentation between the different subsets and the acquisition of altered phenotypes and function. This provides a mechanism for rapid innate immune responsiveness. Here, we discuss the models of differentiation for maintenance and activation of tissue-resident ILCs in maintaining immune homeostasis and protection.

Diverse heterologous primary infections radically alter immunodominance hierarchies and clinical outcomes following H7N9 influenza challenge in mice.

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Susu Duan

2015-02-01

Full Text Available The recent emergence of a novel H7N9 influenza A virus (IAV causing severe human infections in China raises concerns about a possible pandemic. The lack of pre-existing neutralizing antibodies in the broader population highlights the potential protective role of IAV-specific CD8(+ cytotoxic T lymphocyte (CTL memory specific for epitopes conserved between H7N9 and previously encountered IAVs. In the present study, the heterosubtypic immunity generated by prior H9N2 or H1N1 infections significantly, but variably, reduced morbidity and mortality, pulmonary virus load and time to clearance in mice challenged with the H7N9 virus. In all cases, the recall of established CTL memory was characterized by earlier, greater airway infiltration of effectors targeting the conserved or cross-reactive H7N9 IAV peptides; though, depending on the priming IAV, each case was accompanied by distinct CTL epitope immunodominance hierarchies for the prominent K(bPB(1703, D(bPA(224, and D(bNP(366 epitopes. While the presence of conserved, variable, or cross-reactive epitopes between the priming H9N2 and H1N1 and the challenge H7N9 IAVs clearly influenced any change in the immunodominance hierarchy, the changing patterns were not tied solely to epitope conservation. Furthermore, the total size of the IAV-specific memory CTL pool after priming was a better predictor of favorable outcomes than the extent of epitope conservation or secondary CTL expansion. Modifying the size of the memory CTL pool significantly altered its subsequent protective efficacy on disease severity or virus clearance, confirming the important role of heterologous priming. These findings establish that both the protective efficacy of heterosubtypic immunity and CTL immunodominance hierarchies are reflective of the immunological history of the host, a finding that has implications for understanding human CTL responses and the rational design of CTL-mediated vaccines.

Safety and immunogenicity of GamEvac-Combi, a heterologous VSV- and Ad5-vectored Ebola vaccine: An open phase I/II trial in healthy adults in Russia.

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Dolzhikova, I V; Zubkova, O V; Tukhvatulin, A I; Dzharullaeva, A S; Tukhvatulina, N M; Shcheblyakov, D V; Shmarov, M M; Tokarskaya, E A; Simakova, Y V; Egorova, D A; Scherbinin, D N; Tutykhina, I L; Lysenko, A A; Kostarnoy, A V; Gancheva, P G; Ozharovskaya, T A; Belugin, B V; Kolobukhina, L V; Pantyukhov, V B; Syromyatnikova, S I; Shatokhina, I V; Sizikova, T V; Rumyantseva, I G; Andrus, A F; Boyarskaya, N V; Voytyuk, A N; Babira, V F; Volchikhina, S V; Kutaev, D A; Bel'skih, A N; Zhdanov, K V; Zakharenko, S M; Borisevich, S V; Logunov, D Y; Naroditsky, B S; Gintsburg, A L

2017-03-04

Ebola hemorrhagic fever, also known as Ebola virus disease or EVD, is one of the most dangerous viral diseases in humans and animals. In this open-label, dose-escalation clinical trial, we assessed the safety, side effects, and immunogenicity of a novel, heterologous prime-boost vaccine against Ebola, which was administered in 2 doses to 84 healthy adults of both sexes between 18 and 55 years. The vaccine consists of live-attenuated recombinant vesicular stomatitis virus (VSV) and adenovirus serotype-5 (Ad5) expressing Ebola envelope glycoprotein. The most common adverse event was pain at the injection site, although no serious adverse events were reported. The vaccine did not significantly impact blood, urine, and immune indices. Seroconversion rate was 100 %. Antigen-specific IgG geometric mean titer at day 42 was 3,277 (95 % confidence interval 2,401-4,473) in volunteers immunized at full dose. Neutralizing antibodies were detected in 93.1 % of volunteers immunized at full dose, with geometric mean titer 20. Antigen-specific response in peripheral blood mononuclear cells was also detected in 100 % of participants, as well as in CD4+ and CD8+ T cells in 82.8 % and 58.6 % of participants vaccinated at full dose, respectively. The data indicate that the vaccine is safe and induces strong humoral and cellular immune response in up to 100 % of healthy adult volunteers, and provide a rationale for testing efficacy in Phase III trials. Indeed, the strong immune response to the vaccine may elicit long-term protection. This trial was registered with grls.rosminzdrav.ru (No. 495*), and with zakupki.gov.ru (No. 0373100043215000055).

Heterologous expression of a rice metallothionein isoform (OsMTI-1b in Saccharomyces cerevisiae enhances cadmium, hydrogen peroxide and ethanol tolerance

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Zahra Ansarypour

Full Text Available Abstract Metallothioneins are a superfamily of low-molecular-weight, cysteine (Cys-rich proteins that are believed to play important roles in protection against metal toxicity and oxidative stress. The main purpose of this study was to investigate the effect of heterologous expression of a rice metallothionein isoform (OsMTI-1b on the tolerance of Saccharomyces cerevisiae to Cd2+, H2O2 and ethanol stress. The gene encoding OsMTI-1b was cloned into p426GPD as a yeast expression vector. The new construct was transformed to competent cells of S. cerevisiae. After verification of heterologous expression of OsMTI-1b, the new strain and control were grown under stress conditions. In comparison to control strain, the transformed S. cerevisiae cells expressing OsMTI-1b showed more tolerance to Cd2+ and accumulated more Cd2+ ions when they were grown in the medium containing CdCl2. In addition, the heterologous expression of GST-OsMTI-1b conferred H2O2 and ethanol tolerance to S. cerevisiae cells. The results indicate that heterologous expression of plant MT isoforms can enhance the tolerance of S. cerevisiae to multiple stresses.

Resistance and Protective Immunity in Redfish Lake Sockeye Salmon Exposed to M Type Infectious Hematopoietic Necrosis Virus (IHNV)

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Kurath, Gael; Garver, Kyle; Purcell, Maureen K.; LaPatra, Scott E.

2010-01-01

Differential virulence of infectious hematopoietic necrosis virus (IHNV) isolates from the U and M phylogenetic subgroups is clearly evident in the Redfish Lake (RFL) strain of sockeye salmon Oncorhynchus nerka. In these fish, experimental immersion challenges with U isolates cause extremely high mortality and M isolates cause low or no mortality. When survivors of M virus immersion challenges were exposed to a secondary challenge with virulent U type virus they experienced high mortality, indicating that the primary M challenge did not elicit protective immunity. Delivery of a moderate dose (2 × 104 plaque-forming units [PFU]/fish) of virus by intraperitoneal injection challenge did not overcome RFL sockeye salmon resistance to M type IHNV. Injection challenge with a high dose (5 × 106 PFU/fish) of M type virus caused 10% mortality, and in this case survivors did develop protective immunity against a secondary U type virus challenge. Thus, although it is possible for M type IHNV to elicit cross-protective immunity in this disease model, it does not develop after immersion challenge despite entry, transient replication of M virus to low levels, stimulation of innate immune genes, and development of neutralizing antibodies in some fish.

Challenges of Generating and Maintaining Protective Vaccine-Induced Immune Responses for Foot-and-Mouth Disease Virus in Pigs

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Lyons, Nicholas A.; Lyoo, Young S.; King, Donald P.; Paton, David J.

2016-01-01

Vaccination can play a central role in the control of outbreaks of foot-and-mouth disease (FMD) by reducing both the impact of clinical disease and the extent of virus transmission between susceptible animals. Recent incursions of exotic FMD virus lineages into several East Asian countries have highlighted the difficulties of generating and maintaining an adequate immune response in vaccinated pigs. Factors that impact vaccine performance include (i) the potency, antigenic payload, and formulation of a vaccine; (ii) the antigenic match between the vaccine and the heterologous circulating field strain; and (iii) the regime (timing, frequency, and herd-level coverage) used to administer the vaccine. This review collates data from studies that have evaluated the performance of foot-and-mouth disease virus vaccines at the individual and population level in pigs and identifies research priorities that could provide new insights to improve vaccination in the future. PMID:27965966

Host immunity in the protective response to nasal immunization with a pneumococcal antigen associated to live and heat-killed Lactobacillus casei.

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Vintiñi, Elisa O; Medina, Marcela S

2011-08-11

At present, available pneumococcal vaccines have failed to eradicate infections caused by S. pneumoniae. Search for effective vaccine continues and some serotype independent pneumococcal proteins are considered as candidates for the design of new vaccines, especially a mucosal vaccine, since pneumococci enter the body through mucosal surfaces. Selection of the appropriate adjuvant is important for mucosal vaccines, and lactic acid bacteria (LAB) with immunostimulant properties are promissory candidates. In this work, we assessed the adjuvant effect of a probiotic strain, Lactobacillus casei (L. casei), when nasally administered with a pneumococcal antigen (pneumococcal protective protein A: PppA) for the prevention of pneumococcal infection. Adjuvanticity of both live (LcV) and heat-killed (LcM) was evaluated and humoral and cellular antigen-specific immune response was assessed in mucosal and systemic compartments. The potential mechanisms induced by nasal immunization were discussed. Nasal immunization of young mice with PppA+LcV and PppA+LcM induced anti-PppA IgA and IgG antibodies in mucosal and systemic compartments and levels of these specific antibodies remained high even at day 45 after the 3rd Immunization (3rd I). These results were correlated with IL-4 induction by the mixture of antigen plus LcV and LcM. Also, PppA+Lc (V and M) induced stimulation of Th1 and Th17 cells involved in the defence against pneumococci. The protection against pneumococcal respiratory challenge at day 30 after the 3rd I showed that PppA+LcV and PppA+LcM immunizations significantly reduced pathogen counts in nasal lavages while prventing their passage into lung and blood. Survival of mice immunized with the co-application of PppA plus LcV and LcM was significantly higher than in mice immunized with PppA alone and control mice when intraperitoneal challenge was performed. No significant differences between the treatments involving LcV and LcM were found. Live and heat-killed L

Host immunity in the protective response to nasal immunization with a pneumococcal antigen associated to live and heat-killed Lactobacillus casei

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Vintiñi Elisa O

2011-08-01

Full Text Available Abstract Background At present, available pneumococcal vaccines have failed to eradicate infections caused by S. pneumoniae. Search for effective vaccine continues and some serotype independent pneumococcal proteins are considered as candidates for the design of new vaccines, especially a mucosal vaccine, since pneumococci enter the body through mucosal surfaces. Selection of the appropriate adjuvant is important for mucosal vaccines, and lactic acid bacteria (LAB with immunostimulant properties are promissory candidates. In this work, we assessed the adjuvant effect of a probiotic strain, Lactobacillus casei (L. casei, when nasally administered with a pneumococcal antigen (pneumococcal protective protein A: PppA for the prevention of pneumococcal infection. Adjuvanticity of both live (LcV and heat-killed (LcM was evaluated and humoral and cellular antigen-specific immune response was assessed in mucosal and systemic compartments. The potential mechanisms induced by nasal immunization were discussed. Results Nasal immunization of young mice with PppA+LcV and PppA+LcM induced anti-PppA IgA and IgG antibodies in mucosal and systemic compartments and levels of these specific antibodies remained high even at day 45 after the 3rd Immunization (3rd I. These results were correlated with IL-4 induction by the mixture of antigen plus LcV and LcM. Also, PppA+Lc (V and M induced stimulation of Th1 and Th17 cells involved in the defence against pneumococci. The protection against pneumococcal respiratory challenge at day 30 after the 3rd I showed that PppA+LcV and PppA+LcM immunizations significantly reduced pathogen counts in nasal lavages while prventing their passage into lung and blood. Survival of mice immunized with the co-application of PppA plus LcV and LcM was significantly higher than in mice immunized with PppA alone and control mice when intraperitoneal challenge was performed. No significant differences between the treatments involving LcV and

Heterologous Expression of the Oxytetracycline Biosynthetic Pathway in Myxococcus xanthus▿

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Stevens, D. Cole; Henry, Michael R.; Murphy, Kimberly A.; Boddy, Christopher N.

2010-01-01

New natural products for drug discovery may be accessed by heterologous expression of bacterial biosynthetic pathways in metagenomic DNA libraries. However, a “universal” host is needed for this experiment. Herein, we show that Myxococcus xanthus is a potential “universal” host for heterologous expression of polyketide biosynthetic gene clusters. PMID:20208031

Involvement of CD8+ T cell-mediated immune responses in LcrV DNA vaccine induced protection against lethal Yersinia pestis challenge.

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Wang, Shixia; Goguen, Jon D; Li, Fusheng; Lu, Shan

2011-09-09

Yersinia pestis (Y. pestis) is the causative pathogen of plague, a highly fatal disease for which an effective vaccine, especially against mucosal transmission, is still not available. Like many bacterial infections, antigen-specific antibody responses have been traditionally considered critical, if not solely responsible, for vaccine-induced protection against Y. pestis. Studies in recent years have suggested the importance of T cell immune responses against Y. pestis infection but information is still limited about the details of Y. pestis antigen-specific T cell immune responses. In current report, studies are conducted to identify the presence of CD8+ T cell epitopes in LcrV protein, the leading antigen of plague vaccine development. Furthermore, depletion of CD8+ T cells in LcrV DNA vaccinated Balb/C mice led to reduced protection against lethal intranasal challenge of Y. pestis. These findings establish that an LcrV DNA vaccine is able to elicit CD8+ T cell immune responses against specific epitopes of this key plague antigen and that a CD8+ T cell immune response is involved in LcrV DNA vaccine-elicited protection. Future studies in plague vaccine development will need to examine if the presence of detectable T cell immune responses, in particular CD8+ T-cell immune responses, will enhance the protection against Y. pestis in higher animal species or humans. Copyright © 2010 Elsevier Ltd. All rights reserved.

Immunological considerations regarding parental concerns on pediatric immunizations.

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Nicoli, Francesco; Appay, Victor

2017-05-25

Despite the fundamental role of vaccines in the decline of infant mortality, parents may decide to decline vaccination for their own children. Many factors may influence this decision, such as the belief that the infant immune system is weakened by vaccines, and concerns have been raised about the number of vaccines and the early age at which they are administered. Studies focused on the infant immune system and its reaction to immunizations, summarized in this review, show that vaccines can overcome those suboptimal features of infant immune system that render them more at risk of infections and of their severe manifestations. In addition, many vaccines have been shown to improve heterologous innate and adaptive immunity resulting in lower mortality rates for fully vaccinated children. Thus, multiple vaccinations are necessary and not dangerous, as infants can respond to several antigens as well as when responding to single stimuli. Current immunization schedules have been developed and tested to avoid vaccine interference, improve benefits and reduce side effects compared to single administrations. The infant immune system is therefore capable, early after birth, of managing several antigenic challenges and exploits them to prompt its development. Copyright © 2017 Elsevier Ltd. All rights reserved.

Immunization with plasmid DNA encoding the hemagglutinin and the nucleoprotein confers robust protection against a lethal canine distemper virus challenge.

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Dahl, Lotte; Jensen, Trine Hammer; Gottschalck, Elisabeth; Karlskov-Mortensen, Peter; Jensen, Tove Dannemann; Nielsen, Line; Andersen, Mads Klindt; Buckland, Robin; Wild, T Fabian; Blixenkrone-Møller, Merete

2004-09-09

We have investigated the protective effect of immunization of a highly susceptible natural host of canine distemper virus (CDV) with DNA plasmids encoding the viral nucleoprotein (N) and hemagglutinin (H). The combined intradermal and intramuscular routes of immunization elicited high virus-neutralizing serum antibody titres in mink (Mustela vison). To mimic natural exposure, we also conducted challenge infection by horizontal transmission from infected contact animals. Other groups received a lethal challenge infection by administration to the mucosae of the respiratory tract and into the muscle. One of the mink vaccinated with N plasmid alone developed severe disease after challenge. In contrast, vaccination with the H plasmid together with the N plasmid conferred solid protection against disease and we were unable to detect CDV infection in PBMCs or in different tissues after challenge. Our findings show that DNA immunization by the combined intradermal and intramuscular routes can confer solid protective immunity against naturally transmitted morbillivirus infection and disease.

Vesicular stomatitis virus-based vaccines protect nonhuman primates against Bundibugyo ebolavirus.

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Chad E Mire

Full Text Available Ebola virus (EBOV causes severe and often fatal hemorrhagic fever in humans and nonhuman primates (NHPs. Currently, there are no licensed vaccines or therapeutics for human use. Recombinant vesicular stomatitis virus (rVSV-based vaccine vectors, which encode an EBOV glycoprotein in place of the VSV glycoprotein, have shown 100% efficacy against homologous Sudan ebolavirus (SEBOV or Zaire ebolavirus (ZEBOV challenge in NHPs. In addition, a single injection of a blend of three rVSV vectors completely protected NHPs against challenge with SEBOV, ZEBOV, the former Côte d'Ivoire ebolavirus, and Marburg virus. However, recent studies suggest that complete protection against the newly discovered Bundibugyo ebolavirus (BEBOV using several different heterologous filovirus vaccines is more difficult and presents a new challenge. As BEBOV caused nearly 50% mortality in a recent outbreak any filovirus vaccine advanced for human use must be able to protect against this new species. Here, we evaluated several different strategies against BEBOV using rVSV-based vaccines. Groups of cynomolgus macaques were vaccinated with a single injection of a homologous BEBOV vaccine, a single injection of a blended heterologous vaccine (SEBOV/ZEBOV, or a prime-boost using heterologous SEBOV and ZEBOV vectors. Animals were challenged with BEBOV 29-36 days after initial vaccination. Macaques vaccinated with the homologous BEBOV vaccine or the prime-boost showed no overt signs of illness and survived challenge. In contrast, animals vaccinated with the heterologous blended vaccine and unvaccinated control animals developed severe clinical symptoms consistent with BEBOV infection with 2 of 3 animals in each group succumbing. These data show that complete protection against BEBOV will likely require incorporation of BEBOV glycoprotein into the vaccine or employment of a prime-boost regimen. Fortunately, our results demonstrate that heterologous rVSV-based filovirus vaccine

Intranasal immunization of baculovirus displayed hemagglutinin confers complete protection against mouse adapted highly pathogenic H7N7 reassortant influenza virus.

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Subaschandrabose Rajesh Kumar

Full Text Available BACKGROUND: Avian influenza A H7N7 virus poses a pandemic threat to human health because of its ability for direct transmission from domestic poultry to humans and from human to human. The wide zoonotic potential of H7N7 combined with an antiviral immunity inhibition similar to pandemic 1918 H1N1 and 2009 H1N1 influenza viruses is disconcerting and increases the risk of a putative H7N7 pandemic in the future, underlining the urgent need for vaccine development against this virus. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we developed a recombinant vaccine by expressing the H7N7-HA protein on the surface of baculovirus (Bac-HA. The protective efficacy of the live Bac-HA vaccine construct was evaluated in a mouse model by challenging mice immunized intranasally (i.n. or subcutaneously (s.c. with high pathogenic mouse adapted H7N7 reassorted strain. Although s.c. injection of live Bac-HA induced higher specific IgG than i.n. immunization, the later resulted in an elevated neutralization titer. Interestingly, 100% protection from the lethal viral challenge was only observed for the mice immunized intranasally with live Bac-HA, whereas no protection was achieved in any other s.c. or i.n. immunized mice groups. In addition, we also observed higher mucosal IgA as well as increased IFN-γ and IL-4 responses in the splenocytes of the surviving mice coupled with a reduced viral titer and diminished histopathological signs in the lungs. CONCLUSION: Our results indicated that protection from high pathogenic H7N7 (NL/219/03 virus requires both mucosal and systemic immune responses in mice. The balance between Th1 and Th2 cytokines is also required for the protection against the H7N7 pathogen. Intranasal administration of live Bac-HA induced all these immune responses and protected the mice from lethal viral challenge. Therefore, live Bac-HA is an effective vaccine candidate against H7N7 viral infections.

Simultaneous approach using systemic, mucosal and transcutaneous routes of immunization for development of protective HIV-1 vaccines.

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Belyakov, I M; Ahlers, J D

2011-01-01

Mucosal tissues are major sites of HIV entry and initial infection. Induction of a local mucosal cytotoxic T lymphocyte response is considered an important goal in developing an effective HIV vaccine. In addition, activation and recruitment of memory CD4(+) and CD8(+) T cells in systemic lymphoid circulation to mucosal effector sites might provide the firewall needed to prevent virus spread. Therefore a vaccine that generates CD4(+) and CD8(+) responses in both mucosal and systemic tissues might be required for protection against HIV. However, optimal routes and number of vaccinations required for the generation of long lasting CD4(+) and CD8(+) CTL effector and memory responses are not well understood especially for mucosal T cells. A number of studies looking at protective immune responses against diverse mucosal pathogens have shown that mucosal vaccination is necessary to induce a compartmentalized immune response including maximum levels of mucosal high-avidity CD8(+) CTL, antigen specific mucosal antibodies titers (especially sIgA), as well as induction of innate anti-viral factors in mucosa tissue. Immune responses are detectable at mucosal sites after systemic delivery of vaccine, and prime boost regimens can amplify the magnitude of immune responses in mucosal sites and in systemic lymphoid tissues. We believe that the most optimal mucosal and systemic HIV/SIV specific protective immune responses and innate factors might best be achieved by simultaneous mucosal and systemic prime and boost vaccinations. Similar principals of vaccination may be applied for vaccine development against cancer and highly invasive pathogens that lead to chronic infection.

Cold-Adapted Influenza and Recombinant Adenovirus Vaccines Induce Cross-Protective Immunity against pH1N1 Challenge in Mice

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Soboleski, Mark R.; Gabbard, Jon D.; Price, Graeme E.; Misplon, Julia A.; Lo, Chia-Yun; Perez, Daniel R.; Ye, Jianqiang; Tompkins, S. Mark; Epstein, Suzanne L.

2011-01-01

Background The rapid spread of the 2009 H1N1 pandemic influenza virus (pH1N1) highlighted problems associated with relying on strain-matched vaccines. A lengthy process of strain identification, manufacture, and testing is required for current strain-matched vaccines and delays vaccine availability. Vaccines inducing immunity to conserved viral proteins could be manufactured and tested in advance and provide cross-protection against novel influenza viruses until strain-matched vaccines became available. Here we test two prototype vaccines for cross-protection against the recent pandemic virus. Methodology/Principal Findings BALB/c and C57BL/6 mice were intranasally immunized with a single dose of cold-adapted (ca) influenza viruses from 1977 or recombinant adenoviruses (rAd) expressing 1934 nucleoprotein (NP) and consensus matrix 2 (M2) (NP+M2-rAd). Antibodies against the M2 ectodomain (M2e) were seen in NP+M2-rAd immunized BALB/c but not C57BL/6 mice, and cross-reacted with pH1N1 M2e. The ca-immunized mice did not develop antibodies against M2e. Despite sequence differences between vaccine and challenge virus NP and M2e epitopes, extensive cross-reactivity of lung T cells with pH1N1 peptides was detected following immunization. Both ca and NP+M2-rAd immunization protected BALB/c and C57BL/6 mice against challenge with a mouse-adapted pH1N1 virus. Conclusion/Significance Cross-protective vaccines such as NP+M2-rAd and ca virus are effective against pH1N1 challenge within 3 weeks of immunization. Protection was not dependent on recognition of the highly variable external viral proteins and could be achieved with a single vaccine dose. The rAd vaccine was superior to the ca vaccine by certain measures, justifying continued investigation of this experimental vaccine even though ca vaccine is already available. This study highlights the potential for cross-protective vaccines as a public health option early in an influenza pandemic. PMID:21789196

Method for determining heterologous biosynthesis pathways

KAUST Repository

Gao, Xin; Kuwahara, Hiroyuki; Alazmi, Meshari Saud; Cui, Xuefeng

2017-01-01

suitable pathways for the endogenous metabolism of a host organism because the efficacy of heterologous biosynthesis is affected by competing endogenous pathways. The present invention is called MRE (Metabolic Route Explorer), and it was conceived

Immune protection of nonhuman primates against Ebola virus with single low-dose adenovirus vectors encoding modified GPs.

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Nancy J Sullivan

2006-06-01

Full Text Available Ebola virus causes a hemorrhagic fever syndrome that is associated with high mortality in humans. In the absence of effective therapies for Ebola virus infection, the development of a vaccine becomes an important strategy to contain outbreaks. Immunization with DNA and/or replication-defective adenoviral vectors (rAd encoding the Ebola glycoprotein (GP and nucleoprotein (NP has been previously shown to confer specific protective immunity in nonhuman primates. GP can exert cytopathic effects on transfected cells in vitro, and multiple GP forms have been identified in nature, raising the question of which would be optimal for a human vaccine.To address this question, we have explored the efficacy of mutant GPs from multiple Ebola virus strains with reduced in vitro cytopathicity and analyzed their protective effects in the primate challenge model, with or without NP. Deletion of the GP transmembrane domain eliminated in vitro cytopathicity but reduced its protective efficacy by at least one order of magnitude. In contrast, a point mutation was identified that abolished this cytopathicity but retained immunogenicity and conferred immune protection in the absence of NP. The minimal effective rAd dose was established at 10(10 particles, two logs lower than that used previously.Expression of specific GPs alone vectored by rAd are sufficient to confer protection against lethal challenge in a relevant nonhuman primate model. Elimination of NP from the vaccine and dose reductions to 10(10 rAd particles do not diminish protection and simplify the vaccine, providing the basis for selection of a human vaccine candidate.

Immune Protection of Nonhuman Primates against Ebola Virus with Single Low-Dose Adenovirus Vectors Encoding Modified GPs

Science.gov (United States)

Geisbert, Joan B; Shedlock, Devon J; Xu, Ling; Lamoreaux, Laurie; Custers, Jerome H. H. V; Popernack, Paul M; Yang, Zhi-Yong; Pau, Maria G; Roederer, Mario; Koup, Richard A; Goudsmit, Jaap; Jahrling, Peter B; Nabel, Gary J

2006-01-01

Background Ebola virus causes a hemorrhagic fever syndrome that is associated with high mortality in humans. In the absence of effective therapies for Ebola virus infection, the development of a vaccine becomes an important strategy to contain outbreaks. Immunization with DNA and/or replication-defective adenoviral vectors (rAd) encoding the Ebola glycoprotein (GP) and nucleoprotein (NP) has been previously shown to confer specific protective immunity in nonhuman primates. GP can exert cytopathic effects on transfected cells in vitro, and multiple GP forms have been identified in nature, raising the question of which would be optimal for a human vaccine. Methods and Findings To address this question, we have explored the efficacy of mutant GPs from multiple Ebola virus strains with reduced in vitro cytopathicity and analyzed their protective effects in the primate challenge model, with or without NP. Deletion of the GP transmembrane domain eliminated in vitro cytopathicity but reduced its protective efficacy by at least one order of magnitude. In contrast, a point mutation was identified that abolished this cytopathicity but retained immunogenicity and conferred immune protection in the absence of NP. The minimal effective rAd dose was established at 1010 particles, two logs lower than that used previously. Conclusions Expression of specific GPs alone vectored by rAd are sufficient to confer protection against lethal challenge in a relevant nonhuman primate model. Elimination of NP from the vaccine and dose reductions to 1010 rAd particles do not diminish protection and simplify the vaccine, providing the basis for selection of a human vaccine candidate. PMID:16683867

Roles of OspA, OspB, and flagellin in protective immunity to Lyme borreliosis in laboratory mice.

OpenAIRE

Fikrig, E; Barthold, S W; Marcantonio, N; Deponte, K; Kantor, F S; Flavell, R A

1992-01-01

Vaccination with recombinant outer surface protein A (OspA) has been shown to protect mice from infection with Borrelia burgdorferi, the Lyme disease agent. To determine whether antibodies to B. burgdorferi proteins other than OspA are involved in protective immunity, antibodies to OspA were removed from protective anti-B. burgdorferi serum; the residual serum was still protective. Absorption of OspA and OspB antibodies from anti-B. burgdorferi serum eliminated the protective effect. Therefor...

Roles of IFN-γ and γδ T cells in protective immunity against blood-stage malaria

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Shin-Ichi eInoue

2013-08-01

Full Text Available Malaria is caused by infection with Plasmodium parasites. Various studies with knockout mice have indicated that IFN-γ plays essential roles in protective immunity against blood-stage Plasmodium infection. However, after Plasmodium infection, increased IFN-γ production by various types of cells is involved not only in protective immunity, but also in immunopathology. Recent reports have shown that IFN-γ acts as a pro-inflammatory cytokine to induce not only the activation of macrophages, but also the generation of uncommon myelolymphoid progenitor cells after Plasmodium infection. However, the effects of IFN-γ on hematopoietic stem cells and progenitor cells are unclear. Therefore, the regulation of hematopoiesis by IFN-γ during Plasmodium infection remains to be clarified. Although there are conflicting reports concerning the significance of γδ T cells in protective immunity against Plasmodium infection, γδ T cells may respond to infection and produce IFN-γ as innate immune cells in the early phase of blood-stage malaria. Our recent studies have shown that γδ T cells express CD40 ligand and produce IFN-γ after Plasmodium infection, resulting in the enhancement of dendritic cell activation as part of the immune response to eliminate Plasmodium parasites. These data suggest that the function of γδ T cells is similar to that of NK cells. Although several reports suggest that γδ T cells have the potential to act as memory cells for various infections, it remains to be determined whether memory γδ T cells are generated by Plasmodium infection and whether memory γδ T cells can contribute to the host defense against re-infection with Plasmodium. Here, we summarize and discuss the effects of IFN-γ and the various functions of γδ T cells in blood-stage Plasmodium infection.

Evaluation of an economical sunlamp that emits a near solar UV power spectrum for conducting photoimmunological and sunscreen immune protection studies

International Nuclear Information System (INIS)

Beasley, D.G.; Roberts, L.K.; Beard, J.; Stanfield, J.W.

1996-01-01

Unlike FS-type UVB sunlamps, which have a significant amount of effective immunosuppressive non-solar UV energy at wavelengths below 295 nm, the immunosuppression effectiveness spectrum of UVA-340 sunlamps was nearly identical to that of a solar simulator. The purpose of this study was to evaluate this sunlamp for conducting photoimmunological and sunscreen immune protection studies. Groups of C3H mice were exposed to a range of UVA-340 sunlamp doses (0.25 kJ/m 2 to 20.0 kJ/m 2 ) to establish a dose-response curve and determine the minimum immune suppression dose (MISD) for induction of local-type suppression of contact hypersensitivity (CH). The MISD, defined as the lowest UV dose given to produce ∼ 50% suppression of the CH response in mice, was determined to be 1.0 kJ/m 2 for UVA-340 sunlamps. Immune protection tests on four marketed sunscreen lotions (sun protection factors [SPF] 4, 8, 15 and 30) were then conducted with UVA-340 sunlamps using MISD as the endpoint. The immune protection factors for these sunscreens were equivalent to the level of protection predicted by their labeled SPF. These results are similar to those we have previously obtained using a solar simulator. (author)

Immunization

Science.gov (United States)

... a lot worse. Some are even life-threatening. Immunization shots, or vaccinations, are essential. They protect against ... B, polio, tetanus, diphtheria, and pertussis (whooping cough). Immunizations are important for adults as well as children. ...

Immunization of cattle with Ra86 impedes Rhipicephalus appendiculatus nymphal-to-adult molting

NARCIS (Netherlands)

Olds, C.; Mwaura, S.; Crowder, D.; Odongo, D.; Oers, van M.M.; Owen, J.; Bishop, R.; Daubenberger, C.

2012-01-01

Commercial vaccines based on the tick gut protein Bm86 have been successful in controlling the one-host tick Rhipicephalus (Boophilus) microplus and provide heterologous protection against certain other non-target ixodid tick species. This cross protection, however, does not extend to the three-host

Biochemical mechanisms determine the functional compatibility of heterologous genes

DEFF Research Database (Denmark)

Porse, Andreas; Schou, Thea S.; Munck, Christian

2018-01-01

-gene libraries have suggested that sequence composition is a strong barrier for the successful integration of heterologous genes. Here we sample 200 diverse genes, representing >80% of sequenced antibiotic resistance genes, to interrogate the factors governing genetic compatibility in new hosts. In contrast...... factors governing the functionality and fitness of antibiotic resistance genes. These findings emphasize the importance of biochemical mechanism for heterologous gene compatibility, and suggest physiological constraints as a pivotal feature orienting the evolution of antibiotic resistance....

Identifying the Role of E2 Domains on Alphavirus Neutralization and Protective Immune Responses.

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James Weger-Lucarelli

Full Text Available Chikungunya virus (CHIKV and other alphaviruses are the etiologic agents of numerous diseases in both humans and animals. Despite this, the viral mediators of protective immunity against alphaviruses are poorly understood, highlighted by the lack of a licensed human vaccine for any member of this virus genus. The alphavirus E2, the receptor-binding envelope protein, is considered to be the predominant target of the protective host immune response. Although envelope protein domains have been studied for vaccine and neutralization in flaviviruses, their role in alphaviruses is less characterized. Here, we describe the role of the alphavirus E2 domains in neutralization and protection through the use of chimeric viruses.Four chimeric viruses were constructed in which individual E2 domains of CHIKV were replaced with the corresponding domain from Semliki Forest virus (SFV (ΔDomA/ΔDomB/ΔDomC/ ΔDomA+B. Vaccination studies in mice (both live and inactivated virus revealed that domain B was the primary determinant of neutralization. Neutralization studies with CHIKV immune serum from humans were consistent with mouse studies, as ΔDomB was poorly neutralized.Using chimeric viruses, it was determined that the alphavirus E2 domain B was the critical target of neutralizing antibodies in both mice and humans. Therefore, chimeric viruses may have more relevance for vaccine discovery than peptide-based approaches, which only detect linear epitopes. This study provides new insight into the role of alphavirus E2 domains on neutralization determinants and may be useful for the design of novel therapeutic technologies.

Skin innate immune system

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Berna Aksoy

2013-06-01

Full Text Available All multicellular organisms protect themselves from external universe and microorganisms by innate immune sytem that is constitutively present. Skin innate immune system has several different components composed of epithelial barriers, humoral factors and cellular part. In this review information about skin innate immune system and its components are presented to the reader. Innate immunity, which wasn’t adequately interested in previously, is proven to provide a powerfull early protection system, control many infections before the acquired immunity starts and directs acquired immunity to develop optimally

An in silico platform for the design of heterologous pathways in nonnative metabolite production

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Chatsurachai Sunisa

2012-05-01

Full Text Available Abstract Background Microorganisms are used as cell factories to produce valuable compounds in pharmaceuticals, biofuels, and other industrial processes. Incorporating heterologous metabolic pathways into well-characterized hosts is a major strategy for obtaining these target metabolites and improving productivity. However, selecting appropriate heterologous metabolic pathways for a host microorganism remains difficult owing to the complexity of metabolic networks. Hence, metabolic network design could benefit greatly from the availability of an in silico platform for heterologous pathway searching. Results We developed an algorithm for finding feasible heterologous pathways by which nonnative target metabolites are produced by host microorganisms, using Escherichia coli, Corynebacterium glutamicum, and Saccharomyces cerevisiae as templates. Using this algorithm, we screened heterologous pathways for the production of all possible nonnative target metabolites contained within databases. We then assessed the feasibility of the target productions using flux balance analysis, by which we could identify target metabolites associated with maximum cellular growth rate. Conclusions This in silico platform, designed for targeted searching of heterologous metabolic reactions, provides essential information for cell factory improvement.

Exploratory study on Th1 epitope-induced protective immunity against Coxiella burnetii infection.

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Xiaolu Xiong

Full Text Available Coxiella burnetii is a Gram-negative bacterium that causes Q fever in humans. In the present study, 131 candidate peptides were selected from the major immunodominant proteins (MIPs of C. burnetii due to their high-affinity binding capacity for the MHC class II molecule H2 I-A(b based on bioinformatic analyses. Twenty-two of the candidate peptides with distinct MIP epitopes were well recognized by the IFN-γ recall responses of CD4(+ T cells from mice immunized with parental proteins in an ELISPOT assay. In addition, 7 of the 22 peptides could efficiently induce CD4(+ T cells from mice immunized with C. burnetii to rapidly proliferate and significantly increase IFN-γ production. Significantly higher levels of IL-2, IL-12p70, IFN-γ, and TNF-α were also detected in serum from mice immunized with a pool of the 7 peptides. Immunization with the pool of 7 peptides, but not the individual peptides, conferred a significant protection against C. burnetii infection in mice, suggesting that these Th1 peptides could work together to efficiently activate CD4(+ T cells to produce the Th1-type immune response against C. burnetii infection. These observations could contribute to the rational design of molecular vaccines for Q fever.

Partial Protection of Mice against Trypanosoma cruzi after Immunizing with the TcY 72 Antigenic Preparation

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Yara M Gomes

1999-03-01

Full Text Available A 72 kDa Trypanosoma cruzi glycoprotein recognized by the 164C11 monoclonal antibody (IgM isotype was purified by preparative electrophoresis. The antigenic preparation obtained, named TcY 72, was used to immunize C57Bl/10 mice. The following results were observed after immunization: (1 induction of higher titres of IgG than IgM antibodies, as evaluated by indirect immunofluorescence; (2 significant DTH after injection of epimastigotes in mice footpads; (3 peak parasitemia in immunized mice was significantly reduced and animals were negative by 13 days post-infection, although the mice still succumb to infection; (4 the phenotypic analysis of spleen cell populations showed a decrease in the CD4/CD8 ratio in immunized mice. Taken as a whole, these findings indicate that TcY 72 is immunogenic and potentially important for protective immunity.

Protective Immunity Induced by DNA Vaccination against Ranavirus Infection in Chinese Giant Salamander Andrias davidianus

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Zhong-Yuan Chen

2018-01-01

Full Text Available Andrias davidianus ranavirus (ADRV is an emerging viral pathogen that causes severe systemic hemorrhagic disease in Chinese giant salamanders. There is an urgent need for developing an effective vaccine against this fatal disease. In this study, DNA vaccines containing the ADRV 2L gene (pcDNA-2L and the 58L gene (pcDNA-58L were respectively constructed, and their immune protective effects were evaluated in Chinese giant salamanders. In vitro and in vivo expression of the vaccine plasmids were confirmed in transfected cells and muscle tissues of vaccinated Chinese giant salamanders by using immunoblot analysis or RT-PCR. Following ADRV challenge, the Chinese giant salamanders vaccinated with pcDNA-2L showed a relative percent survival (RPS of 66.7%, which was significant higher than that in Chinese giant salamanders immunized with pcDNA-58L (RPS of 3.3%. Moreover, the specific antibody against ADRV was detected in Chinese giant salamanders vaccinated with pcDNA-2L at 14 and 21 days post-vaccination by indirect enzyme-linked immunosorbent assay (ELISA. Transcriptional analysis revealed that the expression levels of immune-related genes including type I interferon (IFN, myxovirus resistance (Mx, major histocompatibility complex class IA (MHC IA, and immunoglobulin M (IgM were strongly up-regulated after vaccination with pcDNA-2L. Furthermore, vaccination with pcDNA-2L significantly suppressed the virus replication, which was seen by a low viral load in the spleen of Chinese giant salamander survivals after ADRV challenge. These results indicated that pcDNA-2L could induce a significant innate immune response and an adaptive immune response involving both humoral and cell-mediated immunity that conferred effective protection against ADRV infection, and might be a potential vaccine candidate for controlling ADRV disease in Chinese giant salamanders.

A Polyprotein-Expressing Salmonid Alphavirus Replicon Induces Modest Protection in Atlantic Salmon (Salmo Salar Against Infectious Pancreatic Necrosis

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Azila Abdullah

2015-01-01

Full Text Available Vaccination is an important strategy for the control and prevention of infectious pancreatic necrosis (IPN in farmed Atlantic salmon (Salmo salar in the post-smolt stage in sea-water. In this study, a heterologous gene expression system, based on a replicon construct of salmonid alphavirus (SAV, was used for in vitro and in vivo expression of IPN virus proteins. The large open reading frame of segment A, encoding the polyprotein NH2-pVP2-VP4-VP3-COOH, as well as pVP2, were cloned and expressed by the SAV replicon in Chinook salmon embryo cells (CHSE-214 and epithelioma papulosum cyprini (EPC cells. The replicon constructs pSAV/polyprotein (pSAV/PP and pSAV/pVP2 were used to immunize Atlantic salmon (Salmo salar by a single intramuscular injection and tested in a subsequent IPN virus (IPNV challenge trial. A low to moderate protection against IPN was observed in fish immunized with the replicon vaccine that encoded the pSAV/PP, while the pSAV/pVP2 construct was not found to induce protection.

Recombinant Kunjin virus replicon vaccines induce protective T-cell immunity against human papillomavirus 16 E7-expressing tumour

International Nuclear Information System (INIS)

Herd, Karen A.; Harvey, Tracey; Khromykh, Alexander A.; Tindle, Robert W.

2004-01-01

The persistence of the E7 oncoprotein in transformed cells in human papillomavirus (HPV)-associated cervical cancer provides a tumour-specific antigen to which immunotherapeutic strategies may be directed. Self-replicating RNA (replicon) vaccine vectors derived from the flavivirus Kunjin (KUN) have recently been reported to induce T-cell immunity. Here, we report that inclusion of a CTL epitope of HPV16 E7 protein into a polyepitope encoded by a KUN vector induced E7-directed T-cell responses and protected mice against challenge with an E7-expressing epithelial tumour. We found replicon RNA packaged into virus-like particles to be more effective than naked replicon RNA or plasmid DNA constructed to allow replicon RNA transcription in vivo. Protective immunity was induced although the E7 CTL epitope was subdominant in the context of other CTL epitopes in the polyepitope. The results demonstrate the efficacy of the KUN replicon vector system for inducing protective immunity directed towards a virally encoded human tumour-specific antigen, and for inducing multi-epitopic CTL responses

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

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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.

Type II collagen in cartilage evokes peptide-specific tolerance and skews the immune response.

Science.gov (United States)

Malmström, V; Kjellén, P; Holmdahl, R

1998-06-01

T cell recognition of type II collagen (CII) is a crucial event in the induction of collagen-induced arthritis in the mouse. Several CII peptides have been shown to be of importance, dependent on which MHC haplotype the mouse carries. By sequencing the rat CII and comparing the sequence with mouse, human, bovine and chicken CII, we have found that the immunodominant peptides all differ at critical positions compared with the autologous mouse sequence. Transgenic expression of the immunodominant Aq-restricted heterologous CII 256-270 epitope inserted into type I collagen (TSC mice) or type II collagen (MMC-1 mice) led to epitope-specific tolerance. Immunization of TSC mice with chick CII led to arthritis and immune responses, dependent on the subdominant, Aq-restricted and chick-specific CII 190-200 epitope. Immunization of F1 mice, expressing both H-2q and H-2r as well as transgenic expression of the Aq-restricted CII 256-270 epitope in cartilage, with bovine CII, led to arthritis, dependent on the Ar-restricted, bovine-specific epitope CII 607-621. These data show that the immunodominance of CII recognition is directed towards heterologous determinants, and that T cells directed towards the corresponding autologous epitopes are tolerated without evidence of active suppression.

Long term protection after immunization with P. berghei sporozoites correlates with sustained IFNγ responses of hepatic CD8+ memory T cells.

Science.gov (United States)

Nganou-Makamdop, Krystelle; van Gemert, Geert-Jan; Arens, Theo; Hermsen, Cornelus C; Sauerwein, Robert W

2012-01-01

Protection against P. berghei malaria can successfully be induced in mice by immunization with both radiation attenuated sporozoites (RAS) arresting early during liver stage development, or sporozoites combined with chloroquine chemoprophylaxis (CPS), resulting in complete intra-hepatic parasite development before killing of blood-stages by chloroquine takes place. We assessed the longevity of protective cellular immune responses by RAS and CPS P. berghei immunization of C57BL/6j mice. Strong effector and memory (T(EM)) CD8+ T cell responses were induced predominantly in the liver of both RAS and CPS immunized mice while CD4+ T cells with memory phenotype remained at base line levels. Compared to unprotected naïve mice, we found high sporozoite-specific IFNγ ex vivo responses that associated with induced levels of in vivo CD8+ T(EM) cells in the liver but not spleen. Long term evaluation over a period of 9 months showed a decline of malaria-specific IFNγ responses in RAS and CPS mice that significantly correlated with loss of protection (r(2) = 0.60, pmemory CD8+ T cells could be boosted by re-exposure to wild-type sporozoites. Our data show that sustainable protection against malaria associates with distinct intra-hepatic immune responses characterized by strong IFNγ producing CD8+ memory T cells.

Long term protection after immunization with P. berghei sporozoites correlates with sustained IFNγ responses of hepatic CD8+ memory T cells.

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Krystelle Nganou-Makamdop

Full Text Available Protection against P. berghei malaria can successfully be induced in mice by immunization with both radiation attenuated sporozoites (RAS arresting early during liver stage development, or sporozoites combined with chloroquine chemoprophylaxis (CPS, resulting in complete intra-hepatic parasite development before killing of blood-stages by chloroquine takes place. We assessed the longevity of protective cellular immune responses by RAS and CPS P. berghei immunization of C57BL/6j mice. Strong effector and memory (T(EM CD8+ T cell responses were induced predominantly in the liver of both RAS and CPS immunized mice while CD4+ T cells with memory phenotype remained at base line levels. Compared to unprotected naïve mice, we found high sporozoite-specific IFNγ ex vivo responses that associated with induced levels of in vivo CD8+ T(EM cells in the liver but not spleen. Long term evaluation over a period of 9 months showed a decline of malaria-specific IFNγ responses in RAS and CPS mice that significantly correlated with loss of protection (r(2 = 0.60, p<0.0001. The reducing IFNγ response by hepatic memory CD8+ T cells could be boosted by re-exposure to wild-type sporozoites. Our data show that sustainable protection against malaria associates with distinct intra-hepatic immune responses characterized by strong IFNγ producing CD8+ memory T cells.

Humoral immune responses to a single allele PfAMA1 vaccine in healthy malaria-naïve adults.

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Edmond J Remarque

Full Text Available Plasmodium falciparum: apical membrane antigen 1 (AMA1 is a candidate malaria vaccine antigen expressed on merozoites and sporozoites. The polymorphic nature of AMA1 may compromise vaccine induced protection. The humoral response induced by two dosages (10 and 50 µg of a single allele AMA1 antigen (FVO formulated with Alhydrogel, Montanide ISA 720 or AS02 was investigated in 47 malaria-naïve adult volunteers. Volunteers were vaccinated 3 times at 4 weekly intervals and serum samples obtained four weeks after the third immunization were analysed for (i Antibody responses to various allelic variants, (ii Domain specificity, (iii Avidity, (iv IgG subclass levels, by ELISA and (v functionality of antibody responses by Growth Inhibition Assay (GIA. About half of the antibodies induced by vaccination cross reacted with heterologous AMA1 alleles. The choice of adjuvant determined the magnitude of the antibody response, but had only a marginal influence on specificity, avidity, domain recognition or subclass responses. The highest antibody responses were observed for AMA1 formulated with AS02. The Growth Inhibition Assay activity of the antibodies was proportional to the amount of antigen specific IgG and the functional capacity of the antibodies was similar for heterologous AMA1-expressing laboratory strains.ClinicalTrials.gov NCT00730782.

Development and evaluation of an efficient heterologous gene knock-in reporter system in Lactococcus lactis.

Science.gov (United States)

Lu, Yifei; Yan, Hongxiang; Deng, Jiezhong; Huang, Zhigang; Jin, Xurui; Yu, Yanlan; Hu, Qiwen; Hu, Fuquan; Wang, Jing

2017-09-18

Lactococcus lactis is a food grade probiotics and widely used to express heterologous proteins. Generally, target genes are knocked into the L. lactis genome through double-crossover recombination to express heterologous proteins stably. However, creating marker-less heterologous genes knocked-in clones is laborious. In this study, an efficient heterologous gene knock-in reporter system was developed in L. lactis NZ9000. Our knock-in reporter system consists of a temperature-sensitive plasmid pJW and a recombinant L. lactis strain named NZB. The pJW contains homologous arms, and was constructed to knock-in heterologous genes at a fixed locus of NZ9000 genome. lacZ (β-galactosidase) gene was knocked into the chromosome of NZ9000 as a counter-selective marker through the plasmid pJW to generate NZB. The engineered NZB strain formed blue colonies on X-Gal plate. The desired double-crossover mutants formed white colonies distinctive from the predominantly blue colonies (parental and plasmid-integrated clones) when the embedded lacZ was replaced with the target heterologous genes carried by pJW in NZB. By using the system, the heterologous gene knocked-in clones are screened by colony phenotype change rather than by checking colonies individually. Our new knock-in reporter system provides an efficient method to create heterologous genes knocked-in clones.

Incorporation of a recombinant Eimeria maxima IMP1 antigen into nanoparticles confers protective immunity against E. Maxima challenge infection.

Science.gov (United States)

Jenkins, Mark C; Stevens, Laura; O'Brien, Celia; Parker, Carolyn; Miska, Katrzyna; Konjufca, Vjollca

2018-02-14

The purpose of this study was to determine if conjugating a recombinant Eimeria maxima protein, namely EmaxIMP1, into 20 nm polystyrene nanoparticles (NP) could improve the level of protective immunity against E. maxima challenge infection. Recombinant EmaxIMP1 was expressed in Escherichia coli as a poly-His fusion protein, purified by NiNTA chromatography, and conjugated to 20 nm polystyrene NP (NP-EmaxIMP1). NP-EMaxIMP1 or control non-recombinant (NP-NR) protein were delivered per os to newly-hatched broiler chicks with subsequent booster immunizations at 3 and 21 days of age. In battery cage studies (n = 4), chickens immunized with NP-EMaxIMP1 displayed complete protection as measured by weight gain (WG) against E. maxima challenge compared to chickens immunized with NP-NR. WG in the NP-EMaxIMP1-immunized groups was identical to WG in chickens that were not infected with E. maxima infected chickens. In floor pen studies (n = 2), chickens immunized with NP-EMaxIMP1 displayed partial protection as measured by WG against E. maxima challenge compared to chickens immunized with NP-NR. In order to understand the basis for immune stimulation, newly-hatched chicks were inoculated per os with NP-EMaxIMP1 or NP-NR protein, and the small intestine, bursa, and spleen, were examined for NP localization at 1 h and 6 h post-inoculation. Within 1 h, both NP-EMaxIMP1 and NP-NR were observed in all 3 tissues. An increase was observed in the level of NP-EmaxIMP1 and NP-NR in all tissues at 6 h post-inoculation. These data indicate that 20 nm NP-EmaxIMP1 or NP-NR reached deeper tissues within hours of oral inoculation and elicited complete to partial immunity against E. maxima challenge infection. Published by Elsevier Ltd.

Mucosal immunization using proteoliposome and cochleate structures from Neisseria meningitidis serogroup B induce mucosal and systemic responses.

Science.gov (United States)

Campo, Judith Del; Zayas, Caridad; Romeu, Belkis; Acevedo, Reinaldo; González, Elizabeth; Bracho, Gustavo; Cuello, Maribel; Cabrera, Osmir; Balboa, Julio; Lastre, Miriam

2009-12-01

Most pathogens either invade the body or establish infection in mucosal tissues and represent an enormous challenge for vaccine development by the absence of good mucosal adjuvants. A proteoliposome-derived adjuvant from Neisseria meningitidis serogroup B (AFPL1, Adjuvant Finlay Proteoliposome 1) and its derived cochleate form (Co, AFCo1) contain multiple pathogen-associated molecular patterns as immunopotentiators, and can also serve as delivery systems to elicit a Th1-type immune response. The present studies demonstrate the ability of AFPL1and AFCo1 to induce mucosal and systemic immune responses by different mucosal immunizations routes and significant adjuvant activity for antibody responses of both structures: a microparticle and a nanoparticle with a heterologous antigen. Therefore, we used female mice immunized by intragastric, intravaginal, intranasal or intramuscular routes with both structures alone or incorporated with ovalbumin (OVA). High levels of specific IgG antibody were detected in all sera and in vaginal washes, but specific IgA antibody in external secretions was only detected in mucosally immunized mice. Furthermore, antigen specific IgG1 and IgG2a isotypes were all induced. AFPL1 and AFCo1 are capable of inducing IFN-gamma responses, and chemokine secretions, like MIP-1alpha and MIP-1beta. However, AFCo1 is a better alternative to induce immune responses at mucosal level. Even when we use a heterologous antigen, the AFCo1 response was better than with AFPL1 in inducing mucosal and systemic immune responses. These results support the use of AFCo1 as a potent Th1 inducing adjuvant particularly suitable for mucosal immunization.

Development of Protective Immunity in New Zealand White Rabbits Challenged with Bacillus anthracis Spores and Treated with Antibiotics and Obiltoxaximab, a Monoclonal Antibody against Protective Antigen.

Science.gov (United States)

Henning, Lisa N; Carpenter, Sarah; Stark, Gregory V; Serbina, Natalya V

2018-02-01

The recommended management of inhalational anthrax, a high-priority bioterrorist threat, includes antibiotics and antitoxins. Obiltoxaximab, a chimeric monoclonal antibody against anthrax protective antigen (PA), is licensed under the U.S. Food and Drug Administration's (FDA's) Animal Rule for the treatment of inhalational anthrax. Because of spore latency, disease reemergence after treatment cessation is a concern, and there is a need to understand the development of endogenous protective immune responses following antitoxin-containing anthrax treatment regimens. Here, acquired protective immunity was examined in New Zealand White (NZW) rabbits challenged with a targeted lethal dose of Bacillus anthracis spores and treated with antibiotics, obiltoxaximab, or a combination of both. Survivors of the primary challenge were rechallenged 9 months later and monitored for survival. Survival rates after primary and rechallenge for controls and animals treated with obiltoxaximab, levofloxacin, or a combination of both were 0, 65, 100, and 95%, and 0, 100, 95, and 89%, respectively. All surviving immune animals had circulating antibodies to PA and serum toxin-neutralizing titers prior to rechallenge. Following rechallenge, systemic bacteremia and toxemia were not detected in most animals, and the levels of circulating anti-PA IgG titers increased starting at 5 days postrechallenge. We conclude that treatment with obiltoxaximab, alone or combined with antibiotics, significantly improves the survival of rabbits that received a lethal inhalation B. anthracis spore challenge dose and does not interfere with the development of immunity. Survivors of primary challenge are protected against reexposure, have rare incidents of systemic bacteremia and toxemia, and have evidence of an anamnestic response. Copyright © 2018 Henning et al.

Development of vaccines against Plasmodium falciparum malaria: taking lessons from naturally acquired protective immunity

DEFF Research Database (Denmark)

Hviid, Lars

2007-01-01

The acquisition of substantial anti-malarial protection in people naturally exposed to P. falciparum is often cited as evidence that malaria vaccines can be developed, but is rarely used to guide the development. We are pursuing the development of vaccines based on antigens and immune responses...

Protective immunity and safety of a genetically modified influenza virus vaccine.

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Rafael Polidoro Alves Barbosa

Full Text Available Recombinant influenza viruses are promising viral platforms to be used as antigen delivery vectors. To this aim, one of the most promising approaches consists of generating recombinant viruses harboring partially truncated neuraminidase (NA segments. To date, all studies have pointed to safety and usefulness of this viral platform. However, some aspects of the inflammatory and immune responses triggered by those recombinant viruses and their safety to immunocompromised hosts remained to be elucidated. In the present study, we generated a recombinant influenza virus harboring a truncated NA segment (vNA-Δ and evaluated the innate and inflammatory responses and the safety of this recombinant virus in wild type or knock-out (KO mice with impaired innate (Myd88 -/- or acquired (RAG -/- immune responses. Infection using truncated neuraminidase influenza virus was harmless regarding lung and systemic inflammatory response in wild type mice and was highly attenuated in KO mice. We also demonstrated that vNA-Δ infection does not induce unbalanced cytokine production that strongly contributes to lung damage in infected mice. In addition, the recombinant influenza virus was able to trigger both local and systemic virus-specific humoral and CD8+ T cellular immune responses which protected immunized mice against the challenge with a lethal dose of homologous A/PR8/34 influenza virus. Taken together, our findings suggest and reinforce the safety of using NA deleted influenza viruses as antigen delivery vectors against human or veterinary pathogens.

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.

Protective effect of yeast β-glucan on immune system of mice irradiated by carbon ions

International Nuclear Information System (INIS)

Wang Ying; Lu Dong; Wei Wei; Jing Xigang; Wang Jufang; Li Wenjian

2012-01-01

Abstract. To detect Yeast β-glucan's protective effect on mice's immune system after C ion beam radiation, mice were used as the test model. We observed the weight, hair color and behavior of mice everyday within a 7 d period of time after irradiation. Meanwhile, the content of white blood cell, on the 2nd and 7th day after irradiation was detected. We detected the thymus and spleen SOD, GSH-PX activity and MDA content of the mice on the 8th day. The results showed that yeast β-glucan could reduce the rapid weight loss of mice, increase white blood cell content, increase thymus and spleen SOD, GSH-PX activity, decrease MDA content of thymus and spleen. These results indicate that yeast 13-glucan can protect mice's immune system against C ion beam radiation damage. (authors)

Heterologous prime-boost vaccination with DNA and MVA vaccines, expressing HIV-1 subtype C mosaic Gag virus-like particles, is highly immunogenic in mice.

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Ros Chapman

Full Text Available In an effort to make affordable vaccines suitable for the regions most affected by HIV-1, we have constructed stable vaccines that express an HIV-1 subtype C mosaic Gag immunogen (BCG-GagM, MVA-GagM and DNA-GagM. Mosaic immunogens have been designed to address the tremendous diversity of this virus. Here we have shown that GagM buds from cells infected and transfected with MVA-GagM and DNA-GagM respectively and forms virus-like particles. Previously we showed that a BCG-GagM prime MVA-GagM boost generated strong cellular immune responses in mice. In this study immune responses to the DNA-GagM and MVA-GagM vaccines were evaluated in homologous and heterologous prime-boost vaccinations. The DNA homologous prime boost vaccination elicited predominantly CD8+ T cells while the homologous MVA vaccination induced predominantly CD4+ T cells. A heterologous DNA-GagM prime MVA-GagM boost induced strong, more balanced Gag CD8+ and CD4+ T cell responses and that were predominantly of an effector memory phenotype. The immunogenicity of the mosaic Gag (GagM was compared to a naturally occurring subtype C Gag (GagN using a DNA homologous vaccination regimen. DNA-GagN expresses a natural Gag with a sequence that was closest to the consensus sequence of subtype C viruses sampled in South Africa. DNA-GagM homologous vaccination induced cumulative HIV-1 Gag-specific IFN-γ ELISPOT responses that were 6.5-fold higher than those induced by the DNA-GagN vaccination. Similarly, DNA-GagM vaccination generated 7-fold higher levels of cytokine-positive CD8+ T cells than DNA-GagN, indicating that this subtype C mosaic Gag elicits far more potent immune responses than a consensus-type Gag. Cells transfected and infected with DNA-GagM and MVA-GagM respectively, expressed high levels of GagM and produced budding virus-like particles. Our data indicates that a heterologous prime boost regimen using DNA and MVA vaccines expressing HIV-1 subtype C mosaic Gag is highly

Shigella IpaB and IpaD displayed on L. lactis bacterium-like particles induce protective immunity in adult and infant mice.

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Heine, Shannon J; Franco-Mahecha, Olga L; Chen, Xiaotong; Choudhari, Shyamal; Blackwelder, William C; van Roosmalen, Maarten L; Leenhouts, Kees; Picking, Wendy L; Pasetti, Marcela F

2015-08-01

Shigella spp. are among the enteric pathogens with the highest attributable incidence of moderate-to-severe diarrhea in children under 5 years of age living in endemic areas. There are no vaccines available to prevent this disease. In this work, we investigated a new Shigella vaccine concept consisting of nonliving, self-adjuvanted, Lactococcus lactis bacterium-like particles (BLP) displaying Shigella invasion plasmid antigen (Ipa) B and IpaD and examined its immunogenicity and protective efficacy in adult and newborn/infant mice immunized via the nasal route. Unique advantages of this approach include the potential for broad protection due to the highly conserved structure of the Ipas and the safety and practicality of a probiotic-based mucosal/adjuvant delivery platform. Immunization of adult mice with BLP-IpaB and BLP-IpaD (BLP-IpaB/D) induced high levels of Ipa-specific serum IgG and stool IgA in a dose-dependent manner. Immune responses and protection were enhanced by BLP delivery. Vaccine-induced serum antibodies exhibited opsonophagocytic and cytotoxic neutralizing activity, and IpaB/D IgG titers correlated with increased survival post-challenge. Ipa-specific antibody secreting cells were detected in nasal tissue and lungs, as well as IgG in bronchoalveolar lavage. Bone marrow cells produced IpaB/D-specific antibodies and contributed to protection after adoptive transfer. The BLP-IpaB/D vaccine conferred 90% and 80% protection against S. flexneri and S. sonnei, respectively. Mice immunized with BLP-IpaB/D as newborns also developed IpaB and IpaD serum antibodies; 90% were protected against S. flexneri and 44% against S. sonnei. The BLP-IpaB/D vaccine is a promising candidate for safe, practical and potentially effective immunization of children against shigellosis.

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

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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.

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

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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)

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

International Nuclear Information System (INIS)

Costa, Andrea da; Galisteo Junior, Andres Jimenez; Andrade Junior, Heitor Franco de

2015-01-01

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 + B, CD3 + CD4 + or CD3 + CD8 + T cell proliferation levels of 5%, while 1.5 kGy-immunized mice exhibited spleen cell proliferation levels of 12.2%, primarily for CD19 + or CD3 + CD8 + lymphocytes and less evidently for CD3 + CD4 + (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)

Previously infected chimpanzees are not consistently protected against reinfection or persistent infection after reexposure to the identical hepatitis C virus strain

DEFF Research Database (Denmark)

Bukh, Jens; Thimme, Robert; Meunier, Jean-Christophe

2008-01-01

Protective immunity after resolved hepatitis C virus (HCV) infection has been reported. However, the breadth of this immunity has remained controversial, and the role of neutralizing antibodies has not been well-defined. In the present study, two chimpanzees (CH96A008 and CH1494) with resolved...... homologous rechallenges with monoclonal H77C or polyclonal H77 and after six heterologous rechallenges with HC-J4 (genotype 1b) or HC-J6 (genotype 2a) viruses. Subsequently, a final challenge with H77C resulted in persistent HCV infection. In both chimpanzees, serum neutralizing antibodies against retroviral...... of viruses recovered from CH1494 after the two homologous rechallenges that resulted in transient viremia were identical with the H77C virus. In contrast, the polyprotein sequences of viruses recovered from both chimpanzees after homologous rechallenge resulting in persistent infection had numerous changes...

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

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T. Scott Devera

2015-06-01

Full Text Available 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.

Host immunity in the protective response to vaccination with heat-killed Burkholderia mallei

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Paessler Slobodan

2008-09-01

Full Text Available Abstract Background We performed initial cell, cytokine and complement depletion studies to investigate the possible role of these effectors in response to vaccination with heat-killed Burkholderia mallei in a susceptible BALB/c mouse model of infection. Results While protection with heat-killed bacilli did not result in sterilizing immunity, limited protection was afforded against an otherwise lethal infection and provided insight into potential host protective mechanisms. Our results demonstrated that mice depleted of either B cells, TNF-α or IFN-γ exhibited decreased survival rates, indicating a role for these effectors in obtaining partial protection from a lethal challenge by the intraperitoneal route. Additionally, complement depletion had no effect on immunoglobulin production when compared to non-complement depleted controls infected intranasally. Conclusion The data provide a basis for future studies of protection via vaccination using either subunit or whole-organism vaccine preparations from lethal infection in the experimental BALB/c mouse model. The results of this study demonstrate participation of B220+ cells and pro-inflammatory cytokines IFN-γ and TNF-α in protection following HK vaccination.

Biomarkers of safety and immune protection for genetically modified live attenuated leishmania vaccines against visceral leishmaniasis - discovery and implications.

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Gannavaram, Sreenivas; Dey, Ranadhir; Avishek, Kumar; Selvapandiyan, Angamuthu; Salotra, Poonam; Nakhasi, Hira L

2014-01-01

Despite intense efforts there is no safe and efficacious vaccine against visceral leishmaniasis, which is fatal and endemic in many tropical countries. A major shortcoming in the vaccine development against blood-borne parasitic agents such as Leishmania is the inadequate predictive power of the early immune responses mounted in the host against the experimental vaccines. Often immune correlates derived from in-bred animal models do not yield immune markers of protection that can be readily extrapolated to humans. The limited efficacy of vaccines based on DNA, subunit, heat killed parasites has led to the realization that acquisition of durable immunity against the protozoan parasites requires a controlled infection with a live attenuated organism. Recent success of irradiated malaria parasites as a vaccine candidate further strengthens this approach to vaccination. We developed several gene deletion mutants in Leishmania donovani as potential live attenuated vaccines and reported extensively on the immunogenicity of LdCentrin1 deleted mutant in mice, hamsters, and dogs. Additional limited studies using genetically modified live attenuated Leishmania parasites as vaccine candidates have been reported. However, for the live attenuated parasite vaccines, the primary barrier against widespread use remains the absence of clear biomarkers associated with protection and safety. Recent studies in evaluation of vaccines, e.g., influenza and yellow fever vaccines, using systems biology tools demonstrated the power of such strategies in understanding the immunological mechanisms that underpin a protective phenotype. Applying similar tools in isolated human tissues such as PBMCs from healthy individuals infected with live attenuated parasites such as LdCen(-/-) in vitro followed by human microarray hybridization experiments will enable us to understand how early vaccine-induced gene expression profiles and the associated immune responses are coordinately regulated in normal

Production of a heterologous proteinase A by Saccharomyces kluyveri

DEFF Research Database (Denmark)

Møller, Kasper; Tidemand, L.D.; Winther, J.R.

2001-01-01

In order to evaluate the potential of Saccharomyces kluyveri for heterologous protein production, S. kluyveri Y159 was transformed with a S. cerevisiae-based multi-copy plasmid containing the S. cerevisiae PEP4 gene, which encodes proteinase A, under the control of its native promoter. As a refer......In order to evaluate the potential of Saccharomyces kluyveri for heterologous protein production, S. kluyveri Y159 was transformed with a S. cerevisiae-based multi-copy plasmid containing the S. cerevisiae PEP4 gene, which encodes proteinase A, under the control of its native promoter...

Enhanced acquired antibodies to a chimeric Plasmodium falciparum antigen; UB05-09 is associated with protective immunity against malaria.

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Dinga, J N; Gamua, S D; Titanji, V P K

2017-08-01

It has been shown that covalently linking two antigens could enhance the immunogenicity of the chimeric construct. To prioritize such a chimera for malaria vaccine development, it is necessary to demonstrate that naturally acquired antibodies against the chimera are associated with protection from malaria. Here, we probe the ability of a chimeric construct of UB05 and UB09 antigens (UB05-09) to better differentiate between acquired immune protection and susceptibility to malaria. In a cross-sectional study, recombinant UB05-09 chimera and the constituent antigens were used to probe for specific antibodies in the plasma from children and adults resident in a malaria-endemic zone, using the enzyme-linked immunosorbent assay (ELISA). Anti-UB05-09 antibody levels doubled that of its constituent antigens, UB09 and UB05, and this correlated with protection against malaria. The presence of enhanced UB05-09-specific antibody correlated with the absence of fever and parasitaemia, which are the main symptoms of malaria infection. The chimera is more effective in detecting and distinguishing acquired protective immunity against malaria than any of its constituents taken alone. Online B-cell epitope prediction tools confirmed the presence of B-cell epitopes in the study antigens. UB05-09 chimera is a marker of protective immunity against malaria that needs to be studied further. © 2017 John Wiley & Sons Ltd.

Hantavirus Gc induces long-term immune protection via LAMP-targeting DNA vaccine strategy.

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Jiang, Dong-Bo; Zhang, Jin-Peng; Cheng, Lin-Feng; Zhang, Guan-Wen; Li, Yun; Li, Zi-Chao; Lu, Zhen-Hua; Zhang, Zi-Xin; Lu, Yu-Chen; Zheng, Lian-He; Zhang, Fang-Lin; Yang, Kun

2018-02-01

Hemorrhagic fever with renal syndrome (HFRS) occurs widely throughout Eurasia. Unfortunately, there is no effective treatment, and prophylaxis remains the best option against the major pathogenic agent, hantaan virus (HTNV), which is an Old World hantavirus. However, the absence of cellular immune responses and immunological memory hampers acceptance of the current inactivated HFRS vaccine. Previous studies revealed that a lysosome-associated membrane protein 1 (LAMP1)-targeting strategy involving a DNA vaccine based on the HTNV glycoprotein Gn successfully conferred long-term immunity, and indicated that further research on Gc, another HTNV antigen, was warranted. Plasmids encoding Gc and lysosome-targeted Gc, designated pVAX-Gc and pVAX-LAMP/Gc, respectively, were constructed. Proteins of interest were identified by fluorescence microscopy following cell line transfection. Five groups of 20 female BALB/c mice were subjected to the following inoculations: inactivated HTNV vaccine, pVAX-LAMP/Gc, pVAX-Gc, and, as the negative controls, pVAX-LAMP or the blank vector pVAX1. Humoral and cellular immunity were assessed by enzyme-linked immunosorbent assays (ELISAs) and 15-mer peptide enzyme-linked immunospot (ELISpot) epitope mapping assays. Repeated immunization with pVAX-LAMP/Gc enhanced adaptive immune responses, as demonstrated by the specific and neutralizing antibody titers and increased IFN-γ production. The inactivated vaccine induced a comparable humoral reaction, but the negative controls only elicited insignificant responses. Using a mouse model of HTNV challenge, the in vivo protection conferred by the inactivated vaccine and Gc-based constructs (with/without LAMP recombination) was confirmed. Evidence of pan-epitope reactions highlighted the long-term cellular response to the LAMP-targeting strategy, and histological observations indicated the safety of the LAMP-targeting vaccines. The long-term protective immune responses induced by pVAX-LAMP/Gc may be

Antibodies to the A27 protein of vaccinia virus neutralize and protect against infection but represent a minor component of Dryvax vaccine--induced immunity.

Science.gov (United States)

He, Yong; Manischewitz, Jody; Meseda, Clement A; Merchlinsky, Michael; Vassell, Russell A; Sirota, Lev; Berkower, Ira; Golding, Hana; Weiss, Carol D

2007-10-01

The smallpox vaccine Dryvax, which consists of replication-competent vaccinia virus, elicits antibodies that play a major role in protection. Several vaccinia proteins generate neutralizing antibodies, but their importance for protection is unknown. We investigated the potency of antibodies to the A27 protein of the mature virion in neutralization and protection experiments and the contributions of A27 antibodies to Dryvax-induced immunity. Using a recombinant A27 protein (rA27), we confirmed that A27 contains neutralizing determinants and that vaccinia immune globulin (VIG) derived from Dryvax recipients contains reactivity to A27. However, VIG neutralization was not significantly reduced when A27 antibodies were removed, and antibodies elicited by an rA27 enhanced the protection conferred by VIG in passive transfer experiments. These findings demonstrate that A27 antibodies do not represent the major fraction of neutralizing activity in VIG and suggest that immunity may be augmented by vaccines and immune globulins that include strong antibody responses to A27.

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

Science.gov (United States)

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

2015-04-08

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

Vaccination with Recombinant Baculovirus Expressing Ranavirus Major Capsid Protein Induces Protective Immunity in Chinese Giant Salamander, Andrias davidianus

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Xiaoyuan Zhou

2017-07-01

Full Text Available The Chinese giant salamander iridovirus (CGSIV, belonging to the genus Ranavirus in the family Iridoviridae, is the causative agent of an emerging infectious disease causing high mortality of more than 90% and economic losses in Chinese giant salamanders in China. In this study, a recombinant baculovirus-based vaccine expressing the CGSIV major capsid protein (MCP was developed and its protective immunity in Chinese giant salamanders was evaluated. The recombinant Autographa californica nucleopolyhedrosis virus (AcNPV, expressing CGSIV MCP, designated as AcNPV-MCP, was generated with the highest titers of 1 × 108 plaque forming units/mL (PFU/mL and confirmed by Western blot and indirect immunofluorescence (IIF assays. Western blot analysis revealed that the expressed MCP reacted with mouse anti-MCP monoclonal antibodies at the band of about 53 kDa. The results of IIF indicated that the MCP was expressed in the infected Spodoptera frugiperda 9 (Sf9 cells with the recombinant baculovirus, and the Chinese giant salamander muscle cells also transduced with the AcNPV-MCP. Immunization with the recombinant baculovirus of AcNPV-MCP elicited robust specific humoral immune responses detected by ELISA and neutralization assays and potent cellular immune responses in Chinese giant salamanders. Importantly, the effective immunization conferred highly protective immunity for Chinese giant salamanders against CGSIV challenge and produced a relative percent of survival rate of 84%. Thus, the recombinant baculovirus expressing CGSIV MCP can induce significant immune responses involving both humoral and cell-mediated immunity in Chinese giant salamanders and might represent a potential baculovirus based vaccine candidate for Chinese giant salamanders against CGSIV.

Experimental Salmonella typhimurium infections in rats. II. Active and passive immunization as protection against a lethal bacterial dose

DEFF Research Database (Denmark)

Hougen, H P; Jensen, E T; Klausen, B

1990-01-01

Immunization against a lethal dose of Salmonella typhimurium was studied in athymic and thymus-bearing LEW rats. Active immunization was performed with formalin-killed whole cell vaccine or sublethal infection prior to the lethal infection. After vaccination with killed bacteria the euthymic...... from immunized thymus grafted animals provided only limited protective effect, and treatment with cells from athymic animals had no effect. The study shows that although isogeneic thymus-grafted nude rats become resistent to reinfection with S. typhimurium, only large doses of spleen cells from...

YopP-expressing variant of Y. pestis activates a potent innate immune response affording cross-protection against yersiniosis and tularemia [corrected].

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Ayelet Zauberman

Full Text Available Plague, initiated by Yersinia pestis infection, is a rapidly progressing disease with a high mortality rate if not quickly treated. The existence of antibiotic-resistant Y. pestis strains emphasizes the need for the development of novel countermeasures against plague. We previously reported the generation of a recombinant Y. pestis strain (Kim53ΔJ+P that over-expresses Y. enterocolitica YopP. When this strain was administered subcutaneously to mice, it elicited a fast and effective protective immune response in models of bubonic, pneumonic and septicemic plague. In the present study, we further characterized the immune response induced by the Kim53ΔJ+P recombinant strain. Using a panel of mouse strains defective in specific immune functions, we observed the induction of a prompt protective innate immune response that was interferon-γ dependent. Moreover, inoculation of mice with Y. pestis Kim53ΔJ+P elicited a rapid protective response against secondary infection by other bacterial pathogens, including the enteropathogen Y. enterocolitica and the respiratory pathogen Francisella tularensis. Thus, the development of new therapies to enhance the innate immune response may provide an initial critical delay in disease progression following the exposure to highly virulent bacterial pathogens, extending the time window for successful treatment.

Immunizations - diabetes

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... this page: //medlineplus.gov/ency/patientinstructions/000331.htm Immunizations - diabetes To use the sharing features on this page, please enable JavaScript. Immunizations (vaccines or vaccinations) help protect you from some ...

Broadly Neutralizing Activity of Zika Virus-Immune Sera Identifies a Single Viral Serotype

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Kimberly A. Dowd

2016-08-01

Full Text Available Recent epidemics of Zika virus (ZIKV have been associated with congenital malformation during pregnancy and Guillain-Barré syndrome. There are two ZIKV lineages (African and Asian that share >95% amino acid identity. Little is known regarding the ability of neutralizing antibodies elicited against one lineage to protect against the other. We investigated the breadth of the neutralizing antibody response following ZIKV infection by measuring the sensitivity of six ZIKV strains to neutralization by ZIKV-confirmed convalescent human serum or plasma samples. Contemporary Asian and early African ZIKV strains were similarly sensitive to neutralization regardless of the cellular source of virus. Furthermore, mouse immune serum generated after infection with African or Asian ZIKV strains was capable of neutralizing homologous and heterologous ZIKV strains equivalently. Because our study only defines a single ZIKV serotype, vaccine candidates eliciting robust neutralizing antibody responses should inhibit infection of both ZIKV lineages, including strains circulating in the Americas.

Heterologous Protein Expression by Lactococcus lactis

NARCIS (Netherlands)

Villatoro-Hernández, J.; Kuipers, O.P.; Saucedo-Cárdenas, O.; Montes-de-Oca-Luna, R.

2012-01-01

This chapter describes the use of Lactococcus lactis as a safe and efficient cell factory to produce heterologous proteins of medical interest. The relevance of the use of this lactic acid bacterium (LAB) is that it is a noncolonizing, nonpathogenic microorganism that can be delivered in vivo at a

Live porcine reproductive and respiratory syndrome virus vaccines: Current status and future direction.

Science.gov (United States)

Renukaradhya, Gourapura J; Meng, Xiang-Jin; Calvert, Jay G; Roof, Michael; Lager, Kelly M

2015-08-07

Porcine reproductive and respiratory syndrome (PRRS) caused by PRRS virus (PRRSV) was reported in the late 1980s. PRRS still is a huge economic concern to the global pig industry with a current annual loss estimated at one billion US dollars in North America alone. It has been 20 years since the first modified live-attenuated PRRSV vaccine (PRRSV-MLV) became commercially available. PRRSV-MLVs provide homologous protection and help in reducing shedding of heterologous viruses, but they do not completely protect pigs against heterologous field strains. There have been many advances in understanding the biology and ecology of PRRSV; however, the complexities of virus-host interaction and PRRSV vaccinology are not yet completely understood leaving a significant gap for improving breadth of immunity against diverse PRRS isolates. This review provides insights on immunization efforts using infectious PRRSV-based vaccines since the 1990s, beginning with live PRRSV immunization, development and commercialization of PRRSV-MLV, and strategies to overcome the deficiencies of PRRSV-MLV through use of replicating viral vectors expressing multiple PRRSV membrane proteins. Finally, powerful reverse genetics systems (infectious cDNA clones) generated from more than 20 PRRSV isolates of both genotypes 1 and 2 viruses have provided a great resource for exploring many innovative strategies to improve the safety and cross-protective efficacy of live PRRSV vaccines. Examples include vaccines with diminished ability to down-regulate the immune system, positive and negative marker vaccines, multivalent vaccines incorporating antigens from other porcine pathogens, vaccines that carry their own cytokine adjuvants, and chimeric vaccine viruses with the potential for broad cross-protection against heterologous strains. To combat this devastating pig disease in the future, evaluation and commercialization of such improved live PRRSV vaccines is a shared goal among PRRSV researchers, pork

Heat shock response improves heterologous protein secretion in Saccharomyces cerevisiae

DEFF Research Database (Denmark)

Hou, Jin; Österlund, Tobias; Liu, Zihe

2013-01-01

The yeast Saccharomyces cerevisiae is a widely used platform for the production of heterologous proteins of medical or industrial interest. However, heterologous protein productivity is often low due to limitations of the host strain. Heat shock response (HSR) is an inducible, global, cellular...... stress response, which facilitates the cell recovery from many forms of stress, e.g., heat stress. In S. cerevisiae, HSR is regulated mainly by the transcription factor heat shock factor (Hsf1p) and many of its targets are genes coding for molecular chaperones that promote protein folding and prevent...... the accumulation of mis-folded or aggregated proteins. In this work, we over-expressed a mutant HSF1 gene HSF1-R206S which can constitutively activate HSR, so the heat shock response was induced at different levels, and we studied the impact of HSR on heterologous protein secretion. We found that moderate and high...

Childhood Immunization

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... lowest levels in history, thanks to years of immunization. Children must get at least some vaccines before ... child provide protection for many years, adults need immunizations too. Centers for Disease Control and Prevention

PROBLEMS IN TESTING DIGITAL PROTECTIVE RELAY FOR IMMUNITY TO INTENTIONAL DESTRUCTIVE ELECTROMAGNETIC IMPACTS. CONTINUATION OF THE THEME

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Vladimir I. Gurevich

2015-12-01

Full Text Available The article is the continuation of the theme highlighted in the previous article with same title. The new article evaluates the results of digital protective relays (DPR testing for immunity to the E1 component of High-altitude Electromagnetic Pulse (HEMP and to Intentional Electromagnetic Interferences (IEMI impacts, conducted by some independent American organizations; discusses the features of relay protection devices as well as clarifies and supplements the procedure for testing these devices. Due to methodology errors during the DPR tests conducted by mentioned organizations earlier, they cannot be considered as satisfactory and their results as meaningful. At the moment there are no reliable data on the level of DPR immunity to IDEI, which suggests that the test should be conducted further.

Kluyveromyces marxianus as a host for heterologous protein synthesis.

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Gombert, Andreas K; Madeira, José Valdo; Cerdán, María-Esperanza; González-Siso, María-Isabel

2016-07-01

The preferentially respiring and thermotolerant yeast Kluyveromyces marxianus is an emerging host for heterologous protein synthesis, surpassing the traditional preferentially fermenting yeast Saccharomyces cerevisiae in some important aspects: K . marxianus can grow at temperatures 10 °C higher than S. cerevisiae, which may result in decreased costs for cooling bioreactors and reduced contamination risk; has ability to metabolize a wider variety of sugars, such as lactose and xylose; is the fastest growing eukaryote described so far; and does not require special cultivation techniques (such as fed-batch) to avoid fermentative metabolism. All these advantages exist together with a high secretory capacity, performance of eukaryotic post-translational modifications, and with a generally regarded as safe (GRAS) status. In the last years, replication origins from several Kluyveromyces spp. have been used for the construction of episomal vectors, and also integrative strategies have been developed based on the tendency for non-homologous recombination displayed by K. marxianus. The recessive URA3 auxotrophic marker and the dominant Kan(R) are mostly used for selection of transformed cells, but other markers have been made available. Homologous and heterologous promoters and secretion signals have been characterized, with the K. marxianus INU1 expression and secretion system being of remarkable functionality. The efficient synthesis of roughly 50 heterologous proteins has been demonstrated, including one thermophilic enzyme. In this mini-review, we summarize the physiological characteristics of K. marxianus relevant for its use in the efficient synthesis of heterologous proteins, the efforts performed hitherto in the development of a molecular toolbox for this purpose, and some successful examples.

Protective immunization with B16 melanoma induces antibody response and not cytotoxic T cell response

International Nuclear Information System (INIS)

Sarzotti, M.; Sriyuktasuth, P.; Klimpel, G.R.; Cerny, J.

1986-01-01

C57BL/6 mice immunized with three intraperitoneal injections of syngeneic, irradiated B16 melanoma cells, became resistant to B16 tumor challenge. Immunized mice had high levels of serum antibody against a membrane antigen of B16 cells. The B16 antigen recognized by the anti-B16 sera formed a major band of 90 KD in gel electrophoresis. The anti-B16 antibody was partially protective when mixed with B16 cells and injected into normal recipient mice. Surprisingly, B16 resistance mice were incapable of generating cytotoxic T cells (CTL) specific for the B16 tumor. Both spleen and lymph node cell populations from immunized mice did not generate B16-specific CTL. Allogeneic mice (DBA/2 or C3H) were also unable to generate B16-specific CTL: however, alloreactive CTL produced in these strains of mice by immunization with C57BL/6 lymphocytes, did kill B16 target cells. Interestingly, spleen cells from syngeneic mice immunized with B16 tumor produced 6-fold more interleukin-2 (IL-2) than normal spleen cells, in vitro. These data suggest that immunization with B16 tumor activates a helper subset of T cells (for antibody and IL-2 production) but not the effector CTL response

Immune Evasion, Immunopathology and the Regulation of the Immune System

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Bruno Faivre

2013-02-01

Full Text Available Costs and benefits of the immune response have attracted considerable attention in the last years among evolutionary biologists. Given the cost of parasitism, natural selection should favor individuals with the most effective immune defenses. Nevertheless, there exists huge variation in the expression of immune effectors among individuals. To explain this apparent paradox, it has been suggested that an over-reactive immune system might be too costly, both in terms of metabolic resources and risks of immune-mediated diseases, setting a limit to the investment into immune defenses. Here, we argue that this view neglects one important aspect of the interaction: the role played by evolving pathogens. We suggest that taking into account the co-evolutionary interactions between the host immune system and the parasitic strategies to overcome the immune response might provide a better picture of the selective pressures that shape the evolution of immune functioning. Integrating parasitic strategies of host exploitation can also contribute to understand the seemingly contradictory results that infection can enhance, but also protect from, autoimmune diseases. In the last decades, the incidence of autoimmune disorders has dramatically increased in wealthy countries of the northern hemisphere with a concomitant decrease of most parasitic infections. Experimental work on model organisms has shown that this pattern may be due to the protective role of certain parasites (i.e., helminths that rely on the immunosuppression of hosts for their persistence. Interestingly, although parasite-induced immunosuppression can protect against autoimmunity, it can obviously favor the spread of other infections. Therefore, we need to think about the evolution of the immune system using a multidimensional trade-off involving immunoprotection, immunopathology and the parasitic strategies to escape the immune response.

Protecting the next generation: what is the role of the duration of human papillomavirus vaccine-related immunity?

Science.gov (United States)

Günther, Oliver P; Ogilvie, Gina; Naus, Monika; Young, Eric; Patrick, David M; Dobson, Simon; Duval, Bernard; Noël, Pierre-André; Marra, Fawziah; Miller, Dianne; Brunham, Robert C; Pourbohloul, Babak

2008-06-15

There is strong evidence that human papillomavirus (HPV) is necessary for the development of cervical cancer. A prophylactic HPV vaccine with high reported efficacy was approved in North America in 2006. A mathematical model of HPV transmission dynamics was used to simulate different scenarios of natural disease outcomes and intervention strategies. A sensitivity analysis was performed to compensate for uncertainties surrounding key epidemiological parameters. The expected impact that HPV vaccines have on cervical cancer incidence and HPV prevalence in the province of British Columbia in Canada revealed that, for lifelong vaccine-related protection, an immunization routine targeting younger females (grade 6), combined with a 3-year program for adolescent females (grade 9), is the most effective strategy. If vaccine-related protection continues for HPV depends substantially on the duration of vaccine-induced immunity. Given the uncertainty in estimating this duration, it may be prudent to assume a value close to the lower limit reported and adjust the program when more-accurate information for the length of vaccine-induced immunity becomes available.

Identification of immune protective genes of Eimeria maxima through cDNA expression library screening.

Science.gov (United States)

Yang, XinChao; Li, MengHui; Liu, JianHua; Ji, YiHong; Li, XiangRui; Xu, LiXin; Yan, RuoFeng; Song, XiaoKai

2017-02-16

Eimeria maxima is one of the most prevalent Eimeria species causing avian coccidiosis, and results in huge economic loss to the global poultry industry. Current control strategies, such as anti-coccidial medication and live vaccines have been limited because of their drawbacks. The third generation anticoccidial vaccines including the recombinant vaccines as well as DNA vaccines have been suggested as a promising alternative strategy. To date, only a few protective antigens of E. maxima have been reported. Hence, there is an urgent need to identify novel protective antigens of E. maxima for the development of neotype anticoccidial vaccines. With the aim of identifying novel protective genes of E. maxima, a cDNA expression library of E. maxima sporozoites was constructed using Gateway technology. Subsequently, the cDNA expression library was divided into 15 sub-libraries for cDNA expression library immunization (cDELI) using parasite challenged model in chickens. Protective sub-libraries were selected for the next round of screening until individual protective clones were obtained, which were further sequenced and analyzed. Adopting the Gateway technology, a high-quality entry library was constructed, containing 9.2 × 10 6 clones with an average inserted fragments length of 1.63 kb. The expression library capacity was 2.32 × 10 7 colony-forming units (cfu) with an average inserted fragments length of 1.64 Kb. The expression library was screened using parasite challenged model in chickens. The screening yielded 6 immune protective genes including four novel protective genes of EmJS-1, EmRP, EmHP-1 and EmHP-2, and two known protective genes of EmSAG and EmCKRS. EmJS-1 is the selR domain-containing protein of E. maxima whose function is unknown. EmHP-1 and EmHP-2 are the hypothetical proteins of E. maxima. EmRP and EmSAG are rhomboid-like protein and surface antigen glycoproteins of E. maxima respectively, and involved in invasion of the parasite. Our

Co-immunization with virus-like particle and DNA vaccines induces protection against respiratory syncytial virus infection and bronchiolitis

Science.gov (United States)

Hwang, Hye Suk; Kwon, Young-Man; Lee, Jong Seok; Yoo, Si-Eun; Lee, Yu-Na; Ko, Eun-Ju; Kim, Min-Chul; Cho, Min-Kyoung; Lee, Young-Tae; Jung, Yu-Jin; Lee, Ji-Yun; Li, Jian Dong; Kang, Sang-Moo

2014-01-01

This study demonstrates that immunization with non-replicating virus-like particle (FFG VLP) containing RSV F and G glycoproteins together with RSV F DNA induced T helper type 1 antibody responses to RSV F similar to live RSV infection. Upon RSV challenge 21 weeks after immunization, FFG VLP vaccination induced protection against RSV infection as shown by clearance of lung viral loads, and the absence of eosinophil infiltrates, and did not cause lung pathology. In contrast, formalin-inactivated RSV (FI-RSV) vaccination showed significant pulmonary eosinophilia, severe mucus production, and extensive histopathology resulting in a hallmark of pulmonary pathology. Substantial lung pathology was also observed in mice with RSV re-infections. High levels of systemic and local inflammatory cytokine-secreting cells were induced in mice with FI-RSV but not with FFG VLP immunization after RSV challenge. Therefore, the results provide evidence that recombinant RSV FFG VLP vaccine can confer long-term protection against RSV without causing lung pathology. PMID:25110201

Immunization of Mice with Recombinant Brucella abortus Organic Hydroperoxide Resistance (Ohr) Protein Protects Against a Virulent Brucella abortus 544 Infection.

Science.gov (United States)

Hop, Huynh Tan; Reyes, Alisha Wehdnesday Bernardo; Simborio, Hannah Leah Tadeja; Arayan, Lauren Togonon; Min, Won Gi; Lee, Hu Jang; Lee, Jin Ju; Chang, Hong Hee; Kim, Suk

2016-01-01

In this study, the Brucella abortus ohr gene coding for an organic hydroperoxide resistance protein (Ohr) was cloned into a maltose fusion protein expression system (pMAL), inserted into Escherichia coli, and purified, and its immunogenicity was evaluated by western blot analysis using Brucella-positive mouse sera. The purified recombinant Ohr (rOhr) was treated with adjuvant and injected intraperitoneally into BALB/c mice. A protective immune response analysis revealed that rOhr induced a significant increase in both the IgG1 and IgG2a titers, and IgG2a reached a higher level than IgG1 after the second and third immunizations. Additionally, immunization with rOhr induced high production of IFN-γ as well as proinflammatory cytokines such as TNF, MCP-1, IL-12p70, and IL-6, but a lesser amount of IL-10, suggesting that rOhr predominantly elicited a cell-mediated immune response. In addition, immunization with rOhr caused a significantly higher degree of protection against a virulent B. abortus infection compared with a positive control group consisting of mice immunized with maltose-binding protein. These findings showed that B. abortus rOhr was able to induce both humoral and cell-mediated immunity in mice, which suggested that this recombinant protein could be a potential vaccine candidate for animal brucellosis.

Efficacy of a high potency O1 Manisa monovalent vaccine against heterologous challenge with foot-and-mouth disease virus of O/SEA/Mya-98 lineage in sheep.

Science.gov (United States)

Singanallur, N B; Pacheco, J M; Arzt, J; Stenfeldt, C; Fosgate, G T; Rodriguez, L; Vosloo, W

2017-09-01

Potency tests for commercial oil-adjuvanted foot-and-mouth disease (FMD) vaccines are usually carried out in cattle, using a full dose (2 ml) of vaccine and homologous virus challenge. However, in sheep the recommended vaccine dose is half of the cattle dose (1 ml) and most vaccines have not been potency tested for this species, especially with heterologous viruses. To determine the efficacy of a high potency (>6PD 50 ) FMD virus (FMDV) O1Manisa vaccine in sheep, we carried out a study using a heterologous FMDV (FMDV O/SKR/2010 - Mya-98 strain) challenge. Groups of seven animals each were vaccinated with 2×, 1×, 1/2× or 1/4× dose (2 ml, 1 ml, 0.5 ml or 0.25 ml respectively) and challenged at 7 days post vaccination (dpv). Only 3 of the 7 sheep in the group vaccinated with 2 ml were protected. With 2 additional groups, receiving double or single doses and challenged at 14 dpv, 4 of 7 sheep were protected in each group. None of the sheep had measurable neutralising antibodies against the vaccine or challenge virus at 7 dpv. However, all vaccinated animals challenged at 14 dpv had a homologous neutralising response against FMDV O1 Manisa on the day of challenge and all but one animal also had a heterologous response to FMDV O/SKR/2010. Infectious FMDV and viral RNA could be found in nasal swabs between 1 and 6 days post challenge (dpc) in most vaccinated sheep, but those vaccinated with higher doses or challenged at 14 dpv showed significant decreases in the level of FMDV detection. Intermittent virus shedding was noticed between 1 and 35 dpc in all vaccinated groups, but persistent infection could be demonstrated only in 4 sheep (20%). This study showed that at the recommended dose, a high potency (>6 PD 50 ) FMDV O1Manisa vaccine does not protect sheep against a heterologous challenge at 7 dpv. However, partial protection was observed when a double dose was used at 7 dpv or when double or single dose vaccinated sheep were challenged at 14 dpv. Copyright �

Biomarkers of Safety and Immune Protection for Genetically Modified Live Attenuated Leishmania Vaccines Against Visceral Leishmaniasis – Discovery and Implications

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Gannavaram, Sreenivas; Dey, Ranadhir; Avishek, Kumar; Selvapandiyan, Angamuthu; Salotra, Poonam; Nakhasi, Hira L.

2014-01-01

Despite intense efforts there is no safe and efficacious vaccine against visceral leishmaniasis, which is fatal and endemic in many tropical countries. A major shortcoming in the vaccine development against blood-borne parasitic agents such as Leishmania is the inadequate predictive power of the early immune responses mounted in the host against the experimental vaccines. Often immune correlates derived from in-bred animal models do not yield immune markers of protection that can be readily extrapolated to humans. The limited efficacy of vaccines based on DNA, subunit, heat killed parasites has led to the realization that acquisition of durable immunity against the protozoan parasites requires a controlled infection with a live attenuated organism. Recent success of irradiated malaria parasites as a vaccine candidate further strengthens this approach to vaccination. We developed several gene deletion mutants in Leishmania donovani as potential live attenuated vaccines and reported extensively on the immunogenicity of LdCentrin1 deleted mutant in mice, hamsters, and dogs. Additional limited studies using genetically modified live attenuated Leishmania parasites as vaccine candidates have been reported. However, for the live attenuated parasite vaccines, the primary barrier against widespread use remains the absence of clear biomarkers associated with protection and safety. Recent studies in evaluation of vaccines, e.g., influenza and yellow fever vaccines, using systems biology tools demonstrated the power of such strategies in understanding the immunological mechanisms that underpin a protective phenotype. Applying similar tools in isolated human tissues such as PBMCs from healthy individuals infected with live attenuated parasites such as LdCen−/− in vitro followed by human microarray hybridization experiments will enable us to understand how early vaccine-induced gene expression profiles and the associated immune responses are coordinately regulated in normal

A boosting skin vaccination with dissolving microneedle patch encapsulating M2e vaccine broadens the protective efficacy of conventional influenza vaccines.

Science.gov (United States)

Zhu, Wandi; Pewin, Winston; Wang, Chao; Luo, Yuan; Gonzalez, Gilbert X; Mohan, Teena; Prausnitz, Mark R; Wang, Bao-Zhong

2017-09-10

The biodegradable microneedle patch (MNP) is a novel technology for vaccine delivery that could improve the immunogenicity of vaccines. To broaden the protective efficiency of conventional influenza vaccines, a new 4M2e-tFliC fusion protein construct containing M2e sequences from different subtypes was generated. Purified fusion protein was encapsulate into MNPs with a biocompatible polymer for use as a boosting vaccine. The results demonstrated that mice receiving a conventional inactivated vaccine followed by a skin-applied dissolving 4M2e-tFliC MNP boost could better maintain the humoral antibody response than that by the conventional vaccine-prime alone. Compared with an intramuscular injection boost, mice receiving the MNP boost showed significantly enhanced cellular immune responses, hemagglutination-inhibition (HAI) titers, and neutralization titers. Increased frequency of antigen-specific plasma cells and long-lived bone marrow plasma cells was detected in the MNP boosted group as well, indicating that skin vaccination with 4M2e-tFliC facilitated a long-term antibody-mediated immunity. The 4M2e-tFliC MNP-boosted group also possessed enhanced protection against high lethal dose challenges against homologous A/PR/8/34 and A/Aichi/2/68 viruses and protection for a majority of immunized mice against a heterologous A/California/07/2009 H1N1 virus. High levels of M2e specific immune responses were observed in the 4M2e-tFliC MNP-boosted group as well. These results demonstrate that a skin-applied 4M2e-tFliC MNP boosting immunization to seasonal vaccine recipients may be a rapid approach for increasing the protective efficacy of seasonal vaccines in response to a significant drift seen in circulating viruses. The results also provide a new perspective for future exploration of universal influenza vaccines. Copyright © 2017 Elsevier B.V. All rights reserved.

Lactobacillus paracasei modulates the immune system of Galleria mellonella and protects against Candida albicans infection

Science.gov (United States)

Rossoni, Rodnei Dennis; Fuchs, Beth Burgwyn; de Barros, Patrícia Pimentel; Velloso, Marisol dos Santos; Jorge, Antonio Olavo Cardoso; Junqueira, Juliana Campos; Mylonakis, Eleftherios

2017-01-01

Probiotics have been described as a potential strategy to control opportunistic infections due to their ability to stimulate the immune system. Using the non-vertebrate model host Galleria mellonella, we evaluated whether clinical isolates of Lactobacillus spp. are able to provide protection against Candida albicans infection. Among different strains of Lactobacillus paracasei, Lactobacillus rhamnosus and Lactobacillus fermentum, we verified that L. paracasei 28.4 strain had the greatest ability to prolong the survival of larvae infected with a lethal dose of C. albicans. We found that the injection of 107 cells/larvae of L. paracasei into G. mellonella larvae infected by C. albicans increased the survival of these insects compared to the control group (P = 0.0001). After that, we investigated the immune mechanisms involved in the protection against C. albicans infection, evaluating the number of hemocytes and the gene expression of antifungal peptides. We found that L. paracasei increased the hemocyte quantity (2.38 x 106 cells/mL) in relation to the control group (1.29 x 106 cells/mL), indicating that this strain is capable of raising the number of circulating hemocytes into the G. mellonella hemolymph. Further, we found that L. paracasei 28.4 upregulated genes that encode the antifungal peptides galiomicin and gallerymicin. In relation to the control group, L. paracasei 28.4 increased gene expression of galiomicin by 6.67-fold and 17.29-fold for gallerymicin. Finally, we verified that the prophylactic provision of probiotic led to a significant reduction of the number of fungal cells in G. mellonella hemolymph. In conclusion, L. paracasei 28.4 can modulate the immune system of G. mellonella and protect against candidiasis. PMID:28267809

Lactobacillus paracasei modulates the immune system of Galleria mellonella and protects against Candida albicans infection.

Science.gov (United States)

Rossoni, Rodnei Dennis; Fuchs, Beth Burgwyn; de Barros, Patrícia Pimentel; Velloso, Marisol Dos Santos; Jorge, Antonio Olavo Cardoso; Junqueira, Juliana Campos; Mylonakis, Eleftherios

2017-01-01

Probiotics have been described as a potential strategy to control opportunistic infections due to their ability to stimulate the immune system. Using the non-vertebrate model host Galleria mellonella, we evaluated whether clinical isolates of Lactobacillus spp. are able to provide protection against Candida albicans infection. Among different strains of Lactobacillus paracasei, Lactobacillus rhamnosus and Lactobacillus fermentum, we verified that L. paracasei 28.4 strain had the greatest ability to prolong the survival of larvae infected with a lethal dose of C. albicans. We found that the injection of 107 cells/larvae of L. paracasei into G. mellonella larvae infected by C. albicans increased the survival of these insects compared to the control group (P = 0.0001). After that, we investigated the immune mechanisms involved in the protection against C. albicans infection, evaluating the number of hemocytes and the gene expression of antifungal peptides. We found that L. paracasei increased the hemocyte quantity (2.38 x 106 cells/mL) in relation to the control group (1.29 x 106 cells/mL), indicating that this strain is capable of raising the number of circulating hemocytes into the G. mellonella hemolymph. Further, we found that L. paracasei 28.4 upregulated genes that encode the antifungal peptides galiomicin and gallerymicin. In relation to the control group, L. paracasei 28.4 increased gene expression of galiomicin by 6.67-fold and 17.29-fold for gallerymicin. Finally, we verified that the prophylactic provision of probiotic led to a significant reduction of the number of fungal cells in G. mellonella hemolymph. In conclusion, L. paracasei 28.4 can modulate the immune system of G. mellonella and protect against candidiasis.

Immunity to sporozoite-induced malaria infection in mice. I. The effect of immunization of T and B cell-deficient mice

International Nuclear Information System (INIS)

Chen, D.H.; Tigelaar, R.E.; Weinbaum, F.I.

1977-01-01

The cellular basis of immunity to sporozoites was investigated by examining the effect of immunization of T and B cell-deficient C57BL/6N x BALB/c AnN F 1 (BLCF 1 ) mice compared to immunocompetent controls. Immunization of T cell-deficient (ATX-BM-ATS) BLCF 1 mice with x-irradiated sporozoites did not result in the generation of protective immunity. The same immunization protocols protected all immunocompetent controls. In contrast, B cell-deficient (μ-suppressed) BLCF 1 mice were protected by immunization in the majority of cases. The absence of detectable serum circumsporozoite precipitins or sporozoite neutralizing activity in the μ-suppressed mice that resisted a sporozoite challenge suggests a minor role for these humoral factors in protection. These data demonstrate a preeminent role for T cells in the induction of protective immunity in BLCF 1 mice against a P. berghei sporozoite infection

The impact of maternally derived immunity on influenza A virus transmission in neonatal pig populations.

Science.gov (United States)

Allerson, Matt; Deen, John; Detmer, Susan E; Gramer, Marie R; Joo, Han Soo; Romagosa, Anna; Torremorell, Montserrat

2013-01-07

The commonality of influenza A virus (IAV) exposure and vaccination on swine farms in the United States ensures that the majority of neonatal pigs will have some degree of maternal immunity to IAV. The influence of maternal immunity on IAV transmission in neonatal pig populations will impact virus prevalence and infection dynamics across pig populations. The main objective of this study was to assess the impact of maternally derived immunity on IAV transmission in an experimental setting. Neonatal pigs suckled colostrum and derived maternal (passive) immunity from sows in one of three treatment groups: (a) non-vaccinated control (CTRL) or vaccinated with (b) homologous (PASSV-HOM) or (c) heterologous (PASSV-HET) inactivated experimental IAV vaccines. Sentinel neonatal pigs derived from the groups above were challenged with IAV via direct contact with an experimentally infected pig (seeder pig) and monitored for IAV infection daily via nasal swab sampling. A susceptible-infectious-recovered (SIR) experimental model was used to obtain and estimate transmission parameters in each treatment group via a generalized linear model. All sentinel pigs in the CTRL (30/30) and PASSV-HET (30/30) groups were infected with IAV following contact with the seeder pigs and the reproduction ratio estimates (95% confidence interval) were 10.4 (6.6-15.8) and 7.1 (4.2-11.3), respectively. In contrast, 1/20 sentinel pigs in the PASSV-HOM group was infected following contact with the seeder pigs and the reproduction ratio estimate was significantly lower compared to the CTRL and PASSV-HET groups at 0.8 (0.1-3.7). Under the conditions of this study, IAV transmission was reduced in neonatal pigs with homologous maternal immunity compared to seronegative neonatal pigs and pigs with heterologous maternal immunity as defined in this study. This study provides estimates for IAV transmission in pigs with differing types of maternal immunity which may describe the influence of maternal immunity on

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

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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. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Induction of Protective Immune Responses against Schistosomiasis Haematobium in Hamsters and Mice Using Cysteine Peptidase-Based Vaccine

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Hatem A M Tallima

2015-03-01

Full Text Available One of the major lessons we learned from the radiation-attenuated cercariae (RA vaccine studies is that protective immunity against schistosomiasis is dependent on the induction of T helper (Th1/Th2-related immune responses. Since most schistosome larval and adult-worm-derived molecules used for vaccination uniformly induce a polarized Th1 response, it was essential to include a type 2 immune responses-inducing molecule, such as cysteine peptidases, in the vaccine formula. Here we demonstrate that a single subcutaneous injection of Syrian hamsters with 200 microg active papain 1 h before percutaneous exposure to 150 cercariae of Schistosoma haematobium led to highly significant (P 50% in worm burden and worm egg counts in intestine. Immunization of hamsters with 20 microg recombinant glyceraldehyde 3-phosphate dehydrogenase (rSG3PDH and 20 ug 2-cys peroxiredoxin-derived peptide in a multiple antigen peptide construct (PRX MAP together with papain (20 microg/hamster as adjuvant led to considerable (64% protection against challenge S. haematobium infection, similar to the levels reported with irradiated cercariae. Cysteine peptidases-based vaccination was also effective in protecting outbred mice against a percutaneous challenge infection with S. haematobium cercariae. In two experiments, a mixture of Schistosoma mansoni cathepsin B1 (SmCB1 and Fasciola hepatica cathepsin L1 (FhCL1 led to highly significant (P < 0.005 reduction of 70% in challenge S. haematobium worm burden and 60% reduction in liver egg counts. Mice vaccinated with SmCB1/FhCL1/ rSG3PDH mixture and challenged with S. haematobium cercariae three weeks after the second immunization displayed highly significant (P < 0.005 reduction of 72% in challenge worm burden and no eggs in liver of 8-10 mice/group, as compared to unimmunized mice, associated with production of a mixture of type 1 and type 2-related cytokines and antibody responses.

Enhancing poxvirus vectors vaccine immunogenicity.

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García-Arriaza, Juan; Esteban, Mariano

2014-01-01

Attenuated recombinant poxvirus vectors expressing heterologous antigens from pathogens are currently at various stages in clinical trials with the aim to establish their efficacy. This is because these vectors have shown excellent safety profiles, significant immunogenicity against foreign expressed antigens and are able to induce protective immune responses. In view of the limited efficacy triggered by some poxvirus strains used in clinical trials (i.e, ALVAC in the RV144 phase III clinical trial for HIV), and of the restrictive replication capacity of the highly attenuated vectors like MVA and NYVAC, there is a consensus that further improvements of these vectors should be pursuit. In this review we considered several strategies that are currently being implemented, as well as new approaches, to improve the immunogenicity of the poxvirus vectors. This includes heterologous prime/boost protocols, use of co-stimulatory molecules, deletion of viral immunomodulatory genes still present in the poxvirus genome, enhancing virus promoter strength, enhancing vector replication capacity, optimizing expression of foreign heterologous sequences, and the combined use of adjuvants. An optimized poxvirus vector triggering long-lasting immunity with a high protective efficacy against a selective disease should be sought.

Prophylactic immunization against experimental leishmaniasis. III. Protection against fatal Leishmania tropica infection induced by irradiated promastigotes involves Lyt-1+2- T cells that do not mediate cutaneous DTH

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Liew, F.Y.; Howard, J.G.; Hale, C.

1984-01-01

Protective immunity against fatal L. tropica infection in genetically vulnerable BALB/c mice can be induced by prophylactic immunization with irradiated promastigotes even when heat-killed. Such immunity is adoptively transferable transiently into intact or durably into sub-lethally irradiated (200 or 550 rad) syngeneic recipients by splenic T but not B cells. The effector T cells are of the Lyt-1 + 2 - phenotype, devoid of demonstrable cytotoxic activity. The immune splenic T cell population expresses specific helper activity for antibody synthesis. A causal role for helper T cells in this capacity, however, seems unlikely, because it was shown that antibody does not determine the protective immunity against L. tropica. The immunized donors show no detectable cutaneous DTH or its early memory recall in response to live or killed promastigotes or a soluble L. tropica antigen preparation. Spleen, lymph node, and peritoneal exudate cells from protectively immunized donors similarly fail to transfer DTH locally or systemically. These cells also lack demonstrable suppressive activity against the expression or induction of DTH to L. tropica. Thus, protection against L. tropica induced by prophylactic i.v. immunization with irradiated promastigotes appears to be conferred by Lyt-1 + 2 - T cells that are distinguishable from T cells mediating either both DTH and T help, or cytotoxicity

Long-term protective immunity from an influenza virus-like particle vaccine administered with a microneedle patch.

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Quan, Fu-Shi; Kim, Yeu-Chun; Song, Jae-Min; Hwang, Hye Suk; Compans, Richard W; Prausnitz, Mark R; Kang, Sang-Moo

2013-09-01

Skin vaccination with influenza virus-like particles (VLPs) using microneedles has been shown to induce protection similar to or better than that induced by intramuscular immunization. In this study, we examined the long-term protective efficacy of influenza (H1N1 A/PR/8/34) VLPs after skin vaccination using microneedle patches coated with the vaccine. Microneedle vaccination of mice in the skin induced 100% protection against lethal challenge infection with influenza A/PR/8/34 virus 14 months after a single vaccine dose. Influenza virus-specific total IgG response and hemagglutination inhibition (HAI) titers were maintained at high levels for over 1 year after microneedle vaccination. Microneedle vaccination also induced substantial levels of lung IgG and IgA antibody responses, and antibody-secreting plasma cells from spleen and bone marrow, as well as conferring effective control of lung viral loads, resulting in complete protection 14 months after vaccination. These strong and long-lasting immune responses were enabled in part by stabilization of the vaccine by formulation with trehalose during microneedle patch fabrication. Administration of the stabilized vaccine using microneedles was especially effective at enabling strong recall responses measured 4 days after lethal virus challenge, including increased HAI and antibody-secreting cells in the spleen and reduced viral titer and inflammatory response in the lung. The results in this study indicate that skin vaccination with VLP vaccine using a microneedle patch provides long-term protection against influenza in mice.

Protective effects of HemoHIM on immune and hematopoietic systems against γ-irradiation.

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Park, Hae-Ran; Jo, Sung-Kee; Jung, Uhee; Yee, Sung-Tae; Kim, Sung-Ho

2014-02-01

We examined the effect of HemoHIM on the protective efficacy of hematopoietic stem cells and on the recovery of immune cells against sublethal doses of ionizing radiation. Two-month-old mice were exposed to γ-rays at a dose of 8, 6.5, or 5 Gy for a30-day survival study, endogenous spleen colony formation, or other experiments, respectively. HemoHIM was injected intraperitoneally before and after irradiation. Our results showed that HemoHIM significantly decreased the mortality of sublethally irradiated mice. The HemoHIM administration decreased the apoptosis of bone marrow cells in irradiated mice. On the other hand, HemoHIM increased the formation of endogenous spleen colony in irradiated mice. In irradiated mice, the recovery of total leukocytes in the peripheral blood and lymphocytes in the spleen were enhanced significantly by HemoHIM. Moreover, the function of B cells, T cells, and NK cells regenerated in irradiated mice were significantly improved by the administration of HemoHIM. HemoHIM showed an ideal radioprotector for protecting hematopoietic stem cells and for accelerating the recovery of immune cells. We propose HemoHIM as a beneficial supplement drug during radiotherapy to alleviate adverse radiation-induced effects for cancer patients. Copyright © 2013 John Wiley & Sons, Ltd.

Induction of long-term protective immune responses by influenza H5N1 virus-like particles.

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Sang-Moo Kang

Full Text Available Recurrent outbreaks of highly pathogenic H5N1 avian influenza virus pose a threat of eventually causing a pandemic. Early vaccination of the population would be the single most effective measure for the control of an emerging influenza pandemic.Influenza virus-like particles (VLPs produced in insect cell-culture substrates do not depend on the availability of fertile eggs for vaccine manufacturing. We produced VLPs containing influenza A/Viet Nam1203/04 (H5N1 hemagglutinin, neuraminidase, and matrix proteins, and investigated their preclinical immunogenicity and protective efficacy. Mice immunized intranasally with H5N1 VLPs developed high levels of H5N1 specific antibodies and were 100% protected against a high dose of homologous H5N1 virus infection at 30 weeks after immunization. Protection is likely to be correlated with humoral and cellular immunologic memory at systemic and mucosal sites as evidenced by rapid anamnestic responses to re-stimulation with viral antigen in vivo and in vitro.These results provide support for clinical evaluation of H5N1 VLP vaccination as a public health intervention to mitigate a possible pandemic of H5N1 influenza.

Immunological response and protection of mice immunized with plasmid encoding Toxoplasma gondii glycolytic enzyme malate dehydrogenase.

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Hassan, I A; Wang, S; Xu, L; Yan, R; Song, X; XiangRui, L

2014-12-01

Toxoplasma gondii Malate dehydrogenase (TgMDH) plays an important role as part of the energy production cycle. In this investigation, immunological changes and protection efficiency of this protein delivered as a DNA vaccine have been evaluated. Mice were intramuscularly immunized with pTgMDH, followed by challenge with virulent T. gondii RH strain, 2 weeks after the booster immunization. Compared to the control groups, the results showed that pTgMDH has stimulated specific humoral response as demonstrated by significant high titers of total IgG and subclasses IgG1 and IgG2a , beside IgA and IgM, but not IgE. Analysis of cytokine profiles revealed significant increases of IFN-γ, IL-4 and IL-17, while no significant changes were detected in TGF-β1. In cell-mediated response, both T lymphocytes subpopulations CD4(+) and CD8(+) were positively recruited as significant percentages were recorded in response to immunization with TgMDH. Significant long survival rate, 17 days, has been observed in the TgMDH vaccinated group, in contrast with control groups which died within 8-9 days after challenge. These results demonstrated that TgMDH could induce significant immunological responses leading to a considerable level of protection against acute toxoplasmosis infection. © 2014 John Wiley & Sons Ltd.

Persistent Low-Level Replication of SIVΔnef Drives Maturation of Antibody and CD8 T Cell Responses to Induce Protective Immunity against Vaginal SIV Infection.

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Adnan, Sama; Reeves, R Keith; Gillis, Jacqueline; Wong, Fay E; Yu, Yi; Camp, Jeremy V; Li, Qingsheng; Connole, Michelle; Li, Yuan; Piatak, Michael; Lifson, Jeffrey D; Li, Wenjun; Keele, Brandon F; Kozlowski, Pamela A; Desrosiers, Ronald C; Haase, Ashley T; Johnson, R Paul

2016-12-01

Defining the correlates of immune protection conferred by SIVΔnef, the most effective vaccine against SIV challenge, could enable the design of a protective vaccine against HIV infection. Here we provide a comprehensive assessment of immune responses that protect against SIV infection through detailed analyses of cellular and humoral immune responses in the blood and tissues of rhesus macaques vaccinated with SIVΔnef and then vaginally challenged with wild-type SIV. Despite the presence of robust cellular immune responses, animals at 5 weeks after vaccination displayed only transient viral suppression of challenge virus, whereas all macaques challenged at weeks 20 and 40 post-SIVΔnef vaccination were protected, as defined by either apparent sterile protection or significant suppression of viremia in infected animals. Multiple parameters of CD8 T cell function temporally correlated with maturation of protection, including polyfunctionality, phenotypic differentiation, and redistribution to gut and lymphoid tissues. Importantly, we also demonstrate the induction of a tissue-resident memory population of SIV-specific CD8 T cells in the vaginal mucosa, which was dependent on ongoing low-level antigenic stimulation. Moreover, we show that vaginal and serum antibody titers inversely correlated with post-challenge peak viral load, and we correlate the accumulation and affinity maturation of the antibody response to the duration of the vaccination period as well as to the SIVΔnef antigenic load. In conclusion, maturation of SIVΔnef-induced CD8 T cell and antibody responses, both propelled by viral persistence in the gut mucosa and secondary lymphoid tissues, results in protective immune responses that are able to interrupt viral transmission at mucosal portals of entry as well as potential sites of viral dissemination.

Partial protective effect of intranasal immunization with recombinant Toxoplasma gondii rhoptry protein 17 against toxoplasmosis in mice.

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Hai-Long Wang

Full Text Available Toxoplasma gondii (T. gondii is an obligate intracellular protozoan parasite that infects a variety of mammals, including humans. An effective vaccine for this parasite is therefore needed. In this study, RH strain T. gondii rhoptry protein 17 was expressed in bacteria as a fusion with glutathione S-transferase (GST and the recombinant proteins (rTgROP17 were purified via GST-affinity chromatography. BALB/c mice were nasally immunised with rTgROP17, and induction of immune responses and protection against chronic and lethal T. gondii infections were investigated. The results revealed that mice immunised with rTgROP17 produced high levels of specific anti-rTgROP17 IgGs and a mixed IgG1/IgG2a response of IgG2a predominance. The systemic immune response was associated with increased production of Th1 (IFN-γand IL-2 and Th2 (IL-4 cytokines, and enhanced lymphoproliferation (stimulation index, SI in the mice immunised with rTgROP17. Strong mucosal immune responses with increased secretion of TgROP17-specific secretory IgA (SIgA in nasal, vaginal and intestinal washes were also observed in these mice. The vaccinated mice displayed apparent protection against chronic RH strain infection as evidenced by their lower liver and brain parasite burdens (59.17% and 49.08%, respectively than those of the controls. The vaccinated mice also exhibited significant protection against lethal infection of the virulent RH strain (survival increased by 50% compared to the controls. Our data demonstrate that rTgROP17 can trigger strong systemic and mucosal immune responses against T. gondii and that ROP17 is a promising candidate vaccine for toxoplasmosis.

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

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Vidya Devi Negi

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

Preexisting Salmonella-specific immunity interferes with the subsequent development of immune responses against the Salmonella strains delivering H9N2 hemagglutinin.

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Hajam, Irshad Ahmed; Lee, John Hwa

2017-06-01

Recombinant Salmonella strains expressing foreign heterologous antigens have been extensively studied as promising live vaccine delivery vehicles. In this study, we constructed attenuated smooth (S-HA) and rough (R-HA) Salmonella strains expressing hemagglutinin (HA) of H9N2, a low pathogenic avian influenza A virus. We then investigated the HA-specific immune responses following oral immunization with either S-HA or R-HA strain in chicken model. We further examined the effects of the preexisting anti-Salmonella immunity on the subsequent elicitation of the HA and the Salmonella ompA specific immune responses. Our results showed that primary immunization with either the S-HA or the R-HA strain elicited comparable HA-specific immune responses and the responses were significantly (pSalmonella vector control. When chickens were pre-immunized with the smooth Salmonella carrier alone and then vaccinated with either S-HA or R-HA strain 3, 6 and 9 weeks later, respectively, significant reductions were seen for HA-specific immune responses at week 6, a point which corresponded to the peak of the primary Salmonella-specific antibody responses. No reductions were seen at week 3 and 9, albeit, the HA-specific immune responses were boosted at week 9, a point which corresponded to the lowest primary Salmonella-specific antibody responses. The ompA recall responses remain refractory at week 3 and 6 following deliberate immunization with the carrier strain, but were significantly (pSalmonella immunity inhibits antigen-specific immune responses and this effect could be avoided by carefully selecting the time point when carrier-specific immune responses are relatively low. Copyright © 2017 Elsevier B.V. All rights reserved.

Antibody quality and protection from lethal Ebola virus challenge in nonhuman primates immunized with rabies virus based bivalent vaccine.

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Blaney, Joseph E; Marzi, Andrea; Willet, Mallory; Papaneri, Amy B; Wirblich, Christoph; Feldmann, Friederike; Holbrook, Michael; Jahrling, Peter; Feldmann, Heinz; Schnell, Matthias J

2013-01-01

We have previously described the generation of a novel Ebola virus (EBOV) vaccine platform based on (a) replication-competent rabies virus (RABV), (b) replication-deficient RABV, or (c) chemically inactivated RABV expressing EBOV glycoprotein (GP). Mouse studies demonstrated safety, immunogenicity, and protective efficacy of these live or inactivated RABV/EBOV vaccines. Here, we evaluated these vaccines in nonhuman primates. Our results indicate that all three vaccines do induce potent immune responses against both RABV and EBOV, while the protection of immunized animals against EBOV was largely dependent on the quality of humoral immune response against EBOV GP. We also determined if the induced antibodies against EBOV GP differ in their target, affinity, or the isotype. Our results show that IgG1-biased humoral responses as well as high levels of GP-specific antibodies were beneficial for the control of EBOV infection after immunization. These results further support the concept that a successful EBOV vaccine needs to induce strong antibodies against EBOV. We also showed that a dual vaccine against RABV and filoviruses is achievable; therefore addressing concerns for the marketability of this urgently needed vaccine.

Antibody quality and protection from lethal Ebola virus challenge in nonhuman primates immunized with rabies virus based bivalent vaccine.

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Joseph E Blaney

Full Text Available We have previously described the generation of a novel Ebola virus (EBOV vaccine platform based on (a replication-competent rabies virus (RABV, (b replication-deficient RABV, or (c chemically inactivated RABV expressing EBOV glycoprotein (GP. Mouse studies demonstrated safety, immunogenicity, and protective efficacy of these live or inactivated RABV/EBOV vaccines. Here, we evaluated these vaccines in nonhuman primates. Our results indicate that all three vaccines do induce potent immune responses against both RABV and EBOV, while the protection of immunized animals against EBOV was largely dependent on the quality of humoral immune response against EBOV GP. We also determined if the induced antibodies against EBOV GP differ in their target, affinity, or the isotype. Our results show that IgG1-biased humoral responses as well as high levels of GP-specific antibodies were beneficial for the control of EBOV infection after immunization. These results further support the concept that a successful EBOV vaccine needs to induce strong antibodies against EBOV. We also showed that a dual vaccine against RABV and filoviruses is achievable; therefore addressing concerns for the marketability of this urgently needed vaccine.

A Schistosoma japonicum chimeric protein with a novel adjuvant induced a polarized Th1 immune response and protection against liver egg burdens

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Xue Xiangyang

2009-05-01

Full Text Available Abstract Background Schitosomiasis japonica is still a significant public health problem in China. A protective vaccine for human or animal use represents an important strategy for long-term control of this disease. Due to the complex life cycle of schistosomes, different vaccine design approaches may be necessary, including polyvalent subunit vaccines. In this study, we constructed four chimeric proteins (designated SjGP-1~4 via fusion of Sj26GST and four individual paramyosin fragments. We tested these four proteins as vaccine candidates, and investigated the effect of deviating immune response on protection roles in mice. Methods The immunogencity and protection efficacy of chimeric proteins were evaluated in mice. Next, the chimeric protein SjGP-3 was selected and formulated in various adjuvants, including CFA, ISA 206, IMS 1312 and ISA 70M. The titers of antigen-specific IgG, IgE and IgG subclass were measured. The effect of adjuvant on cytokine production and percentages of CD3+CD8-IFN-γ+ cells and CD3+CD8-IL-4+ cells were analyzed at different time points. Worm burdens and liver egg counts in different adjuvant groups were counted to evaluate the protection efficacy against cercarial challenge. Results Immunization of mice with chimeric proteins provided various levels of protection. Among the four proteins, SjGP-3 induced the highest level of protection, and showed enhanced protective efficacy compared with its individual component Sj26GST. Because of this, SjGP-3 was further formulated in various adjuvants to investigate the effect of adjuvant on immune deviation. The results revealed that SjGP-3 formulated in veterinary adjuvant ISA 70M induced a lasting polarized Th1 immune response, whereas the other adjuvants, including CFA, ISA 206 and IMS 1312, generated a moderate mixed Th1/Th2 response after immunization but all except for IMS 1312 shifted to Th2 response after onset of eggs. More importantly, the SjGP-3/70M formulation induced

DNA prime/Adenovirus boost malaria vaccine encoding P. falciparum CSP and AMA1 induces sterile protection associated with cell-mediated immunity.

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Ilin Chuang

Full Text Available BACKGROUND: Gene-based vaccination using prime/boost regimens protects animals and humans against malaria, inducing cell-mediated responses that in animal models target liver stage malaria parasites. We tested a DNA prime/adenovirus boost malaria vaccine in a Phase 1 clinical trial with controlled human malaria infection. METHODOLOGY/PRINCIPAL FINDINGS: The vaccine regimen was three monthly doses of two DNA plasmids (DNA followed four months later by a single boost with two non-replicating human serotype 5 adenovirus vectors (Ad. The constructs encoded genes expressing P. falciparum circumsporozoite protein (CSP and apical membrane antigen-1 (AMA1. The regimen was safe and well-tolerated, with mostly mild adverse events that occurred at the site of injection. Only one AE (diarrhea, possibly related to immunization, was severe (Grade 3, preventing daily activities. Four weeks after the Ad boost, 15 study subjects were challenged with P. falciparum sporozoites by mosquito bite, and four (27% were sterilely protected. Antibody responses by ELISA rose after Ad boost but were low (CSP geometric mean titer 210, range 44-817; AMA1 geometric mean micrograms/milliliter 11.9, range 1.5-102 and were not associated with protection. Ex vivo IFN-γ ELISpot responses after Ad boost were modest (CSP geometric mean spot forming cells/million peripheral blood mononuclear cells 86, range 13-408; AMA1 348, range 88-1270 and were highest in three protected subjects. ELISpot responses to AMA1 were significantly associated with protection (p = 0.019. Flow cytometry identified predominant IFN-γ mono-secreting CD8+ T cell responses in three protected subjects. No subjects with high pre-existing anti-Ad5 neutralizing antibodies were protected but the association was not statistically significant. SIGNIFICANCE: The DNA/Ad regimen provided the highest sterile immunity achieved against malaria following immunization with a gene-based subunit vaccine (27%. Protection

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.

Phi (Φ) and psi (Ψ) angles involved in malarial peptide bonds determine sterile protective immunity.

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Patarroyo, Manuel E; Moreno-Vranich, Armando; Bermúdez, Adriana

2012-12-07

Modified HABP (mHABP) regions interacting with HLA-DRβ1(∗) molecules have a more restricted conformation and/or sequence than other mHABPs which do not fit perfectly into their peptide binding regions (PBR) and do not induce an acceptable immune response due to the critical role of their Φ and Ψ torsion angles. These angle's critical role was determined in such highly immunogenic, protection-inducing response against experimental malaria using the conformers (mHABPs) obtained by (1)H-NMR and superimposed into HLA-DRβ1(∗)-like Aotus monkey molecules; their phi (Φ) and psi (Ψ) angles were measured and the H-bond formation between these molecules was evaluated. The aforementioned mHABP propensity to assume a regular conformation similar to a left-handed polyproline type II helix (PPII(L)) led to suggesting that favouring these conformations according to their amino acid sequence would lead to high antibody titre production and sterile protective immunity induction against malaria, thereby adding new principles or rules for vaccine development, malaria being one of them. Copyright © 2012 Elsevier Inc. All rights reserved.

Interleukin-21 receptor signalling is important for innate immune protection against HSV-2 infections.

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Sine K Kratholm

Full Text Available Interleukin (IL -21 is produced by Natural Killer T (NKT cells and CD4(+ T cells and is produced in response to virus infections, where IL-21 has been shown to be essential in adaptive immune responses. Cells from the innate immune system such as Natural Killer (NK cells and macrophages are also important in immune protection against virus. These cells express the IL-21 receptor (IL-21R and respond to IL-21 with increased cytotoxicity and cytokine production. Currently, however it is not known whether IL-21 plays a significant role in innate immune responses to virus infections. The purpose of this study was to investigate the role of IL-21 and IL-21R in the innate immune response to a virus infection. We used C57BL/6 wild type (WT and IL-21R knock out (KO mice in a murine vaginal Herpes Simplex Virus type 2 (HSV-2 infection model to show that IL-21 - IL-21R signalling is indeed important in innate immune responses against HSV-2. We found that the IL-21R was expressed in the vaginal epithelium in uninfected (u.i WT mice, and expression increased early after HSV-2 infection. IL-21R KO mice exhibited increased vaginal viral titers on day 2 and 3 post infection (p.i. and subsequently developed significantly higher disease scores and a lower survival rate compared to WT mice. In addition, WT mice infected with HSV-2 receiving intra-vaginal pre-treatment with murine recombinant IL-21 (mIL-21 had decreased vaginal viral titers on day 2 p.i., significantly lower disease scores, and a higher survival rate compared to infected untreated WT controls. Collectively our data demonstrate the novel finding that the IL-21R plays a critical role in regulating innate immune responses against HSV-2 infection.

Nasally administered Lactobacillus rhamnosus strains differentially modulate respiratory antiviral immune responses and induce protection against respiratory syncytial virus infection.

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Tomosada, Yohsuke; Chiba, Eriko; Zelaya, Hortensia; Takahashi, Takuya; Tsukida, Kohichiro; Kitazawa, Haruki; Alvarez, Susana; Villena, Julio

2013-08-15

Some studies have shown that nasally administered immunobiotics had the potential to improve the outcome of influenza virus infection. However, the capacity of immunobiotics to improve protection against respiratory syncytial virus (RSV) infection was not investigated before. The aims of this study were: a) to evaluate whether the nasal administration of Lactobacillus rhamnosus CRL1505 (Lr05) and L. rhamnosus CRL1506 (Lr06) are able to improve respiratory antiviral defenses and beneficially modulate the immune response triggered by TLR3/RIG-I activation; b) to investigate whether viability of Lr05 or Lr06 is indispensable to modulate respiratory immunity and; c) to evaluate the capacity of Lr05 and Lr06 to improve the resistance of infant mice against RSV infection. Nasally administered Lr05 and Lr06 differentially modulated the TLR3/RIG-I-triggered antiviral respiratory immune response. Lr06 administration significantly modulated the production of IFN-α, IFN-β and IL-6 in the response to poly(I:C) challenge, while nasal priming with Lr05 was more effective to improve levels of IFN-γ and IL-10. Both viable Lr05 and Lr06 strains increased the resistance of infant mice to RSV infection while only heat-killed Lr05 showed a protective effect similar to those observed with viable strains. The present work demonstrated that nasal administration of immunobiotics is able to beneficially modulate the immune response triggered by TLR3/RIG-I activation in the respiratory tract and to increase the resistance of mice to the challenge with RSV. Comparative studies using two Lactobacillus rhamnosus strains of the same origin and with similar technological properties showed that each strain has an specific immunoregulatory effect in the respiratory tract and that they differentially modulate the immune response after poly(I:C) or RSV challenges, conferring different degree of protection and using distinct immune mechanisms. We also demonstrated in this work that it is possible

Recombinant TgHSP70 Immunization Protects against Toxoplasma gondii Brain Cyst Formation by Enhancing Inducible Nitric Oxide Expression

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Neide M. Silva

2017-04-01

Full Text Available Toxoplasma gondii is known to cause congenital infection in humans and animals and severe disease in immunocompromised individuals; consequently development of vaccines against the parasite is highly necessary. Under stress conditions, T. gondii expresses the highly immunogenic heat shock protein 70 (TgHSP70. Here, we assessed the protective efficacy of rTgHSP70 immunization combined with Alum in oral ME-49 T. gondii infection and the mechanisms involved on it. It was observed that immunized mice with rTgHSP70 or rTgHSP70 adsorbed in Alum presented a significantly reduced number of cysts in the brain that was associated with increased iNOS+ cell numbers in the organ, irrespective the use of the adjuvant. Indeed, ex vivo experiments showed that peritoneal macrophages pre-stimulated with rTgHSP70 presented increased NO production and enhanced parasite killing, and the protein was able to directly stimulate B cells toward antibody producing profile. In addition, rTgHSP70 immunization leads to high specific antibody titters systemically and a mixed IgG1/IgG2a response, with predominance of IgG1 production. Nonetheless, it was observed that the pretreatment of the parasite with rTgHSP70 immune sera was not able to control T. gondii internalization and replication by NIH fibroblast neither peritoneal murine macrophages, nor anti-rTgHSP70 antibodies were able to kill T. gondii by complement-mediated lysis, suggesting that these mechanisms are not crucial to resistance. Interestingly, when in combination with Alum, rTgHSP70 immunization was able to reduce inflammation in the brain of infected mice and in parallel anti-rTgHSP70 immune complexes in the serum. In conclusion, immunization with rTgHSP70 induces massive amounts of iNOS expression and reduced brain parasitism, suggesting that iNOS expression and consequently NO production in the brain is a protective mechanism induced by TgHSP70 immunization, therefore rTgHSP70 can be a good candidate for

Biomarkers of safety and immune protection for genetically modified live attenuated Leishmania vaccines against visceral leishmaniasis-Discovery and implications

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Sreenivas eGannavaram

2014-05-01

Full Text Available Despite intense efforts there is no safe and efficacious vaccine against visceral leishmaniasis, which is fatal and endemic in many tropical countries. A major shortcoming in the vaccine development against blood borne parasitic agents such as Leishmania is the inadequate predictive power of the early immune responses mounted in the host against the experimental vaccines. Often immune correlates derived from in-bred animal models do not yield immune markers of protection that can be readily extrapolated to humans. The limited efficacy of vaccines based on DNA, sub-unit, heat killed parasites has led to the realization that acquisition of durable immunity against the protozoan parasites requires a controlled infection with a live attenuated organism. Recent success of irradiated malaria parasites as a vaccine candidate further strengthens this approach to vaccination. We developed several gene deletion mutants in L. donovani as potential live attenuated vaccines and reported extensively on the immunogenicity of LdCentrin1 deleted mutant in mice, hamsters and dogs. Additional limited studies using genetically modified live attenuated Leishmania parasites as vaccine candidates have been reported. However, for the live attenuated parasite vaccines, the primary barrier against widespread use remains the absence of clear biomarkers associated with protection and safety. Recent studies in evaluation of vaccines e.g., influenza and yellow fever vaccines, using systems biology tools demonstrated the power of such strategies in understanding the immunological mechanisms that underpin a protective phenotype. Applying similar tools in isolated human tissues such as PBMCs from healthy individuals infected with live attenuated parasites such as LdCen1-/- in vitro followed by human microarray hybridization experiments will enable us to understand how early vaccine-induced gene expression profiles and the associated immune responses are coordinately regulated

Protective immunity against Megalocytivirus infection in rock bream (Oplegnathus fasciatus) following CpG ODN administration.

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Jung, Myung-Hwa; Lee, Jehee; Ortega-Villaizan, M; Perez, Luis; Jung, Sung-Ju

2017-06-27

Rock bream iridovirus (RBIV) disease in rock bream (Oplegnathus fasciatus) remains an unsolved problem in Korea aquaculture farms. CpG ODNs are known as immunostimulant, can improve the innate immune system of fish providing resistance to diseases. In this study, we evaluated the potential of CpG ODNs to induce anti-viral status protecting rock bream from different RBIV infection conditions. We found that, when administered into rock bream, CpG ODN 1668 induces better antiviral immune responses compared to other 5 CpG ODNs (2216, 1826, 2133, 2395 and 1720). All CpG ODN 1668 administered fish (1/5µg) at 2days before infection (1.1×10 7 ) held at 26°C died even though mortality was delayed from 8days (1µg) and 4days (5µg). Similarly, CpG ODN 1668 administered (5µg) at 2days before infection (1.2×10 6 ) held at 23/20°C had 100% mortality; the mortality was delayed from 9days (23°C) and 11days (20°C). Moreover, when CpG ODN 1668 administered (1/5/10µg) at 2/4/7days before infection or virus concentration was decreased to 1.1×10 4 and held at 20°C had mortality rates of 20/60/30% (2days), 30/40/60% (4days) and 60/60/20% (7days), respectively, for the respective administration dose, through 100 dpi. To investigate the development of a protective immune response, survivors were re-infected with RBIV (1.1×10 7 ) at 100 and 400 dpi, respectively. While 100% of the previously unexposed fish died, 100% of the previously infected fish survived. The high survival rate of fish following re-challenge with RBIV indicates that protective immunity was established in the surviving rock bream. Our results showed the possibility of developing preventive measures against RBIV using CpG ODN 1668 by reducing RBIV replication speed (i.e. water temperature of 20°C and infection dose of 1.1×10 4 ). Copyright © 2017 Elsevier Ltd. All rights reserved.

Transcutaneous immunization with a novel imiquimod nanoemulsion induces superior T cell responses and virus protection.

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Lopez, Pamela Aranda; Denny, Mark; Hartmann, Ann-Kathrin; Alflen, Astrid; Probst, Hans Christian; von Stebut, Esther; Tenzer, Stefan; Schild, Hansjörg; Stassen, Michael; Langguth, Peter; Radsak, Markus P

2017-09-01

Transcutaneous immunization (TCI) is a novel vaccination strategy utilizing the skin associated lymphatic tissue to induce immune responses. TCI using a cytotoxic T lymphocyte (CTL) epitope and the Toll-like receptor 7 (TLR7) agonist imiquimod mounts strong CTL responses by activation and maturation of skin-derived dendritic cells (DCs) and their migration to lymph nodes. However, TCI based on the commercial formulation Aldara only induces transient CTL responses that needs further improvement for the induction of durable therapeutic immune responses. Therefore we aimed to develop a novel imiquimod solid nanoemulsion (IMI-Sol) for TCI with superior vaccination properties suited to induce high quality T cell responses for enhanced protection against infections. TCI was performed by applying a MHC class I or II restricted epitope along with IMI-Sol or Aldara (each containing 5% Imiquimod) on the shaved dorsum of C57BL/6, IL-1R, Myd88, Tlr7 or Ccr7 deficient mice. T cell responses as well as DC migration upon TCI were subsequently analyzed by flow cytometry. To determine in vivo efficacy of TCI induced immune responses, CTL responses and frequency of peptide specific T cells were evaluated on day 8 or 35 post vaccination and protection in a lymphocytic choriomeningitis virus (LCMV) infection model was assessed. TCI with the imiquimod formulation IMI-Sol displayed equal skin penetration of imiquimod compared to Aldara, but elicited superior CD8 + as well as CD4 + T cell responses. The induction of T-cell responses induced by IMI-Sol TCI was dependent on the TLR7/MyD88 pathway and independent of IL-1R. IMI-Sol TCI activated skin-derived DCs in skin-draining lymph nodes more efficiently compared to Aldara leading to enhanced protection in a LCMV infection model. Our data demonstrate that IMI-Sol TCI can overcome current limitations of previous imiquimod based TCI approaches opening new perspectives for transcutaneous vaccination strategies and allowing the use of this

Sm29, but not Sm22.6 retains its ability to induce a protective immune response in mice previously exposed to a Schistosoma mansoni infection.

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Clarice Carvalho Alves

2015-02-01

Full Text Available BACKGROUND: A vaccine against schistosomiasis would have a great impact in disease elimination. Sm29 and Sm22.6 are two parasite tegument proteins which represent promising antigens to compose a vaccine. These antigens have been associated with resistance to infection and reinfection in individuals living in endemic area for the disease and induced partial protection when evaluated in immunization trials using naïve mice. METHODOLOGY/PRINCIPALS FINDINGS: In this study we evaluated rSm29 and rSm22.6 ability to induce protection in Balb/c mice that had been previously infected with S. mansoni and further treated with Praziquantel. Our results demonstrate that three doses of the vaccine containing rSm29 were necessary to elicit significant protection (26%-48%. Immunization of mice with rSm29 induced a significant production of IL-2, IFN-γ, IL-17, IL-4; significant production of specific antibodies; increased percentage of CD4+ central memory cells in comparison with infected and treated saline group and increased percentage of CD4+ effector memory cells in comparison with naïve Balb/c mice immunized with rSm29. On the other hand, although immunization with Sm22.6 induced a robust immune response, it failed to induce protection. CONCLUSION/SIGNIFICANCE: Our results demonstrate that rSm29 retains its ability to induce protection in previously infected animals, reinforcing its potential as a vaccine candidate.

METHOD FOR THE PRODUCTION OF HETEROLOGOUS POLYPEPTIDES IN TRANSFORMED YEAST CELLS

DEFF Research Database (Denmark)

2000-01-01

The invention describes industrial fermentation of a $i(Saccharomyces) yeast species for production of a heterologous product encoded by a plasmid or DNA contained in said $i(Saccharomyces) yeast species with method utilizes the substrate more efficiently and without fermentative metabolism...... resulting in formation of ethanol and other unwanted primary products of fermentative activity whereby high yields of the heterologous product are obtained. The $i(Saccharomyces) yeast species is preferably a Crabtree negative $i(Saccharomyces species) in particular $i(Saccharomyces kluyveri)....

Trans-generational Immune Priming Protects the Eggs Only against Gram-Positive Bacteria in the Mealworm Beetle

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Dubuffet, Aurore; Zanchi, Caroline; Boutet, Gwendoline; Moreau, Jérôme; Teixeira, Maria; Moret, Yannick

2015-01-01

In many vertebrates and invertebrates, offspring whose mothers have been exposed to pathogens can exhibit increased levels of immune activity and/or increased survival to infection. Such phenomena, called “Trans-generational immune priming” (TGIP) are expected to provide immune protection to the offspring. As the offspring and their mother may share the same environment, and consequently similar microbial threats, we expect the immune molecules present in the progeny to be specific to the microbes that immune challenged the mother. We provide evidence in the mealworm beetle Tenebrio molitor that the antimicrobial activity found in the eggs is only active against Gram-positive bacteria, even when females were exposed to Gram-negative bacteria or fungi. Fungi were weak inducers of TGIP while we obtained similar levels of anti-Gram-positive activity using different bacteria for the maternal challenge. Furthermore, we have identified an antibacterial peptide from the defensin family, the tenecin 1, which spectrum of activity is exclusively directed toward Gram-positive bacteria as potential contributor to this antimicrobial activity. We conclude that maternal transfer of antimicrobial activity in the eggs of T. molitor might have evolved from persistent Gram-positive bacterial pathogens between insect generations. PMID:26430786

Trans-generational Immune Priming Protects the Eggs Only against Gram-Positive Bacteria in the Mealworm Beetle.

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Aurore Dubuffet

2015-10-01

Full Text Available In many vertebrates and invertebrates, offspring whose mothers have been exposed to pathogens can exhibit increased levels of immune activity and/or increased survival to infection. Such phenomena, called "Trans-generational immune priming" (TGIP are expected to provide immune protection to the offspring. As the offspring and their mother may share the same environment, and consequently similar microbial threats, we expect the immune molecules present in the progeny to be specific to the microbes that immune challenged the mother. We provide evidence in the mealworm beetle Tenebrio molitor that the antimicrobial activity found in the eggs is only active against Gram-positive bacteria, even when females were exposed to Gram-negative bacteria or fungi. Fungi were weak inducers of TGIP while we obtained similar levels of anti-Gram-positive activity using different bacteria for the maternal challenge. Furthermore, we have identified an antibacterial peptide from the defensin family, the tenecin 1, which spectrum of activity is exclusively directed toward Gram-positive bacteria as potential contributor to this antimicrobial activity. We conclude that maternal transfer of antimicrobial activity in the eggs of T. molitor might have evolved from persistent Gram-positive bacterial pathogens between insect generations.

Vaccination with a DNA vaccine encoding Toxoplasma gondii ROP54 induces protective immunity against toxoplasmosis in mice.

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Yang, Wen-Bin; Zhou, Dong-Hui; Zou, Yang; Chen, Kai; Liu, Qing; Wang, Jin-Lei; Zhu, Xing-Quan; Zhao, Guang-Hui

2017-12-01

Toxoplasma gondii is an obligatory intracellular protozoan, which infects most of the warm-blooded animals, causing serious public health problems and enormous economic losses worldwide. The rhoptry effector protein 54 (ROP54) has been indicated as a virulence factor that promotes Toxoplasma infection by modulating GBP2 loading onto parasite-containing vacuoles, which can modulate some aspects of the host immune response. In order to evaluate the immuno-protective value of ROP54, we constructed a eukaryotic recombinant plasmid expressing T. gondii ROP54 and intramuscularly immunized Kunming mice with this recombinant plasmid against acute and chronic toxoplasmosis. All mice immunized with pVAX-ROP54 elicited a high level of specific antibody responses, a significant increase of lymphocyte proliferation, and a significant level of Th1-type cytokines (IFN-γ, IL-2 and IL-12p70), in addition to an increased production of Th2-type cytokines (IL-4 and IL-10). These results demonstrated that pVAX-ROP54 induced significant cellular and humoral (Th1/Th2) immune responses, which extended the survival time (13.0±1.15days for pVAX-ROP54 vs 6.7±0.48days for pVAX I, 6.8±0.42days for PBS and 6.5±0.53 for blank control) and significantly reduced cyst burden (35.9% for pVAX-ROP54, 1% for pVAX I and 2% for PBS, compared with blank control) of immunized mice. These results indicate that the recombinant ROP54 plasmid can provide partial protection and might be a potential vaccine candidate against acute and chronic toxoplasmosis. Copyright © 2017 Elsevier B.V. All rights reserved.

A Functional Food Mixture “Protector” Reinforces the Protective Immune Parameters against Viral Flu Infection in Mice

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Kenza A. Mansoor

2018-06-01

Full Text Available Background: Viral influenza infection causes serious health issues especially when an outbreak occurs. Although influenza virus vaccines are available and each year manufactures modify the vaccine depending on the expected mutated strain, it is still far from satisfactory, mainly in young children and older adults. Therefore, a product that can support and shape the immune system to protect against viral flu infections is highly essential. Methods: A functional food water-soluble mixture of pomegranate, red grape, dates, olive fruit, figs, and ginger extracts, termed herein “Protector”, was prepared and tested in stimulating/modulating the production of specific cytokines, and hemagglutinin inhibition (HAI antibodies following viral flu vaccination in mice. Results: A single intraperitoneal or multiple oral administration for 1–7 days of “Protector” significantly increased the production of interferon (IFN-γ and interleukin (IL-12 in blood, spleen, and lungs of mice. When “Protector” was orally administered for one week following a single vaccine injection (primary immunization or for two weeks (one week apart following double vaccine injections (secondary immunization, mice significantly produced higher titers of HAI antibodies. This increase in HAI antibodies was associated with Pillow-inducing significant and different changes in vaccine-induced IFN-γ, IL-12, IL-6 and IL-22 following primary and secondary immunizations. Conclusions: “Protector” administration reinforces the protective immune parameters against viral flu infection. Therefore, after performing preclinical toxicology studies and ensuring its safety, “Protector” should be considered a potential product to be tested in clinical trials to conclude its efficacy in reducing the devastating effects of flu infection in humans and its outbreaks.

The 17D-204 Vaccine Strain-Induced Protection against Virulent Yellow Fever Virus Is Mediated by Humoral Immunity and CD4+ but not CD8+ T Cells.

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Watson, Alan M; Lam, L K Metthew; Klimstra, William B; Ryman, Kate D

2016-07-01

A gold standard of antiviral vaccination has been the safe and effective live-attenuated 17D-based yellow fever virus (YFV) vaccines. Among more than 500 million vaccinees, only a handful of cases have been reported in which vaccinees developed a virulent wild type YFV infection. This efficacy is presumed to be the result of both neutralizing antibodies and a robust T cell response. However, the particular immune components required for protection against YFV have never been evaluated. An understanding of the immune mechanisms that underlie 17D-based vaccine efficacy is critical to the development of next-generation vaccines against flaviviruses and other pathogens. Here we have addressed this question for the first time using a murine model of disease. Similar to humans, vaccination elicited long-term protection against challenge, characterized by high neutralizing antibody titers and a robust T cell response that formed long-lived memory. Both CD4+ and CD8+ T cells were polyfunctional and cytolytic. Adoptive transfer of immune sera or CD4+ T cells provided partial protection against YFV, but complete protection was achieved by transfer of both immune sera and CD4+ T cells. Thus, robust CD4+ T cell activity may be a critical contributor to protective immunity elicited by highly effective live attenuated vaccines.

Induction of protective immunity against Eimeria tenella, Eimeria necatrix, Eimeria maxima and Eimeria acervulina infections using multivalent epitope DNA vaccines.

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Song, Xiaokai; Ren, Zhe; Yan, Ruofeng; Xu, Lixin; Li, Xiangrui

2015-06-04

Avian coccidiosis is mostly caused by mixed infection of several Eimeria species under natural conditions and immunity to avian coccidiosis is largely dependent on T-cell immune response. In this study, 14 T-cell epitope fragments from eight antigens of Eimeria tenella (E. tenella), Eimeria necatrix (E. necatrix), Eimeria maxima (E. maxima) and Eimeria acervulina (E. acervulina) were ligated with pVAX1 producing 14 monovalent DNA vaccines, respectively. Protective immunity of the monovalent DNA vaccines was assessed by in vivo challenge experiments and then four most protective fragments of each species were chosen to construct multivalent epitope DNA vaccines with or without chicken IL-2 as genetic adjuvant. Protective efficacies of the epitope DNA vaccines on chickens against E. tenella, E. necatrix, E. maxima and E. acervulina were evaluated. The results showed that the constructed multivalent epitope DNA vaccines significantly increased body weight gain, alleviated enteric lesions and reduced oocyst output of the infected birds. Especially, the multivalent epitope DNA vaccines of pVAX1-NA4-1-TA4-1-LDH-2-EMCDPK-1 and pVAX1-NA4-1-TA4-1-LDH-2-EMCDPK-1-IL-2 not only significantly increased body weight gain, alleviated enteric lesions and reduced oocyst output of the infected birds, but also resulted in anti-coccidial index (ACI) more than 170 against E. tenella, E. necatrix, E. maxima and E. acervulina, which indicated they could induce protective immunity against E. tenella, E. necatrix, E. maxima and E. acervulina. Our findings suggest the constructed multivalent epitope DNA vaccines are the potential candidate multivalent vaccines against mixed infection of Eimeria. Copyright © 2015 Elsevier Ltd. All rights reserved.