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Mariano Esteban - One of the best experts on this subject based on the ideXlab platform.

  • distinct immunogenicity and efficacy of Poxvirus based vaccine candidates against ebola virus expressing gp and vp40 proteins
    Journal of Virology, 2018
    Co-Authors: Adrian Lazarofrias, Karl Ljungberg, Mariano Esteban, Peter Liljeström, Sergio Gomezmedina, Lucas Sanchezsampedro, Mart Ustav, Cesar Munozfontela, Juan Garciaarriaza
    Abstract:

    Zaire and Sudan ebolavirus species cause a severe disease in humans and nonhuman primates (NHPs) characterized by a high mortality rate. There are no licensed therapies or vaccines against Ebola virus disease (EVD), and the recent 2013 to 2016 outbreak in West Africa highlighted the need for EVD-specific medical countermeasures. Here, we generated and characterized head-to-head the immunogenicity and efficacy of five vaccine candidates against Zaire ebolavirus (EBOV) and Sudan ebolavirus (SUDV) based on the highly attenuated Poxvirus Vector modified vaccinia virus Ankara (MVA) expressing either the virus glycoprotein (GP) or GP together with the virus protein 40 (VP40) forming virus-like particles (VLPs). In a human monocytic cell line, the different MVA Vectors (termed MVA-EBOVs and MVA-SUDVs) triggered robust innate immune responses, with production of beta interferon (IFN-β), proinflammatory cytokines, and chemokines. Additionally, several innate immune cells, such as dendritic cells, neutrophils, and natural killer cells, were differentially recruited in the peritoneal cavity of mice inoculated with MVA-EBOVs. After immunization of mice with a homologous prime/boost protocol (MVA/MVA), total IgG antibodies against GP or VP40 from Zaire and Sudan ebolavirus were differentially induced by these Vectors, which were mainly of the IgG1 and IgG3 isotypes. Remarkably, an MVA-EBOV construct coexpressing GP and VP40 protected chimeric mice challenged with EBOV to a greater extent than a Vector expressing GP alone. These results support the consideration of MVA-EBOVs and MVA-SUDVs expressing GP and VP40 and producing VLPs as best-in-class potential vaccine candidates against EBOV and SUDV.IMPORTANCE EBOV and SUDV cause a severe hemorrhagic fever affecting humans and NHPs. Since their discovery in 1976, they have caused several sporadic epidemics, with the recent outbreak in West Africa from 2013 to 2016 being the largest and most severe, with more than 11,000 deaths being reported. Although some vaccines are in advanced clinical phases, less expensive, safer, and more effective licensed vaccines are desirable. We generated and characterized head-to-head the immunogenicity and efficacy of five novel vaccines against EBOV and SUDV based on the Poxvirus MVA expressing GP or GP and VP40. The expression of GP and VP40 leads to the formation of VLPs. These MVA-EBOV and MVA-SUDV recombinants triggered robust innate and humoral immune responses in mice. Furthermore, MVA-EBOV recombinants expressing GP and VP40 induced high protection against EBOV in a mouse challenge model. Thus, MVA expressing GP and VP40 and producing VLPs is a promising vaccine candidate against EBOV and SUDV.

  • Development of a Safe and Effective Vaccinia Virus Oncolytic Vector WR-Δ4 with a Set of Gene Deletions on Several Viral Pathways.
    Molecular therapy oncolytics, 2017
    Co-Authors: Ernesto Mejías-pérez, Liliana Carreño-fuentes, Mariano Esteban
    Abstract:

    Despite the effectiveness of classic treatments and available diagnostic tools, cancer continues to be a leading world health problem, with devastating cancer-related death rates. Advances in oncolytic virotherapy have shown promise as potentially effective treatment options in the fight against cancer. The Poxviruses have many features that make them an attractive platform for the development of oncolytic Vectors, with some candidates currently in clinical trials. Here, we report the design and generation of a new oncolytic Vector based on the vaccinia virus Western Reserve (WR) strain. We show that the WR-Δ4 virus, with the combined deletion of four specific viral genes that act on metabolic, proliferation, and signaling pathways (A48R, B18R, C11R, and J2R), has effective anti-tumor capabilities in vivo. In WR-Δ4-infected mice, we observed strong viral attenuation, reduced virus dissemination, and efficient tumor cell growth control in the B16F10 syngeneic melanoma model, with enhanced neutrophil migration and activation of tumor antigen-specific immune responses. This approach provides an alternative strategy toward ongoing efforts to develop an optimal oncolytic Poxvirus Vector.

  • Kinetic and Phenotypic Analysis of CD8+ T Cell Responses after Priming with Alphavirus Replicons and Homologous or Heterologous Booster Immunizations
    Journal of Virology, 2014
    Co-Authors: Maria L. Knudsen, Karl Ljungberg, Maria Kakoulidou, Linda Kostic, David Hallengärd, Juan García-arriaza, Andres Merits, Mariano Esteban, Peter Liljeström
    Abstract:

    Alphavirus replicons are potent inducers of CD8+ T cell responses and thus constitute an attractive vaccine Vector platform for developing novel vaccines. However, the kinetics and memory phenotype of CD8+ T cell responses induced by alphavirus replicons are not well characterized. Furthermore, little is known how priming with alphavirus replicons affects booster immune responses induced by other vaccine modalities. We demonstrate here that a single immunization with an alphavirus replicon, administered as viral particles or naked DNA, induced an antigen-specific CD8+ T cell response that had a sharp peak, followed by a rapid contraction. Administering a homologous boost before contraction had occurred did not further increase the response. In contrast, boosting after contraction when CD8+ T cells had obtained a memory phenotype (based on CD127/CD62L expression), resulted in maintenance of CD8+ T cells with a high recall capacity (based on CD27/CD43 expression). Increasing the dose of replicon particles promoted T effector memory (Tem) and inhibited T central memory development. Moreover, infection with a replicating alphavirus induced a similar distribution of CD8+ T cells as the replicon Vector. Lastly, the distribution of T cell subpopulations induced by a DNA-launched alphavirus replicon could be altered by heterologous boosts. For instance, boosting with a Poxvirus Vector (MVA) favored expansion of the Tem compartment. In summary, we have characterized the antigen-specific CD8+ T cell response induced by alphavirus replicon Vectors and demonstrated how it can be altered by homologous and heterologous boost immunizations. IMPORTANCE Alphavirus replicons are promising vaccine candidates against a number of diseases and are by themselves developed as vaccines against, for example, Chikungunya virus infection. Replicons are also considered to be used for priming, followed by booster immunization using different vaccine modalities. In order to rationally design prime-boost immunization schedules with these Vectors, characterization of the magnitude and phenotype of CD8+ T cell responses induced by alphavirus replicons is needed. Here, we demonstrate how factors such as timing and dose affect the phenotypes of memory T cell populations induced by immunization with alphavirus replicons. These findings are important for designing future clinical trials with alphaviruses, since they can be used to tailor vaccination regimens in order to induce a CD8+ T cell response that is optimal for control and/or clearance of a specific pathogen.

  • Enhancing Poxvirus Vectors vaccine immunogenicity
    Human vaccines & immunotherapeutics, 2014
    Co-Authors: Juan García-arriaza, Mariano Esteban
    Abstract:

    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.

  • A Novel Poxvirus-based Vaccine (MVA-CHIKV) is Highly Immunogenic and Protects Mice against Chikungunya Infection
    Journal of virology, 2014
    Co-Authors: Juan García-arriaza, David Hallengärd, Peter Liljeström, Victoria Cepeda, Carlos Oscar S. Sorzano, Beate M. Kümmerer, Mariano Esteban
    Abstract:

    There is a need to develop a single and highly effective vaccine against the emerging chikungunya virus (CHIKV), which causes a severe disease in humans. Here, we have generated and characterized the immunogenicity profile and the efficacy of a novel CHIKV vaccine candidate based on the highly attenuated Poxvirus Vector modified vaccinia virus Ankara (MVA) expressing the CHIKV C, E3, E2, 6K, and E1 structural genes (termed MVA-CHIKV). MVA-CHIKV was stable in cell culture, expressed the CHIKV structural proteins, and triggered the cytoplasmic accumulation of Golgi apparatus-derived membranes in infected human cells. Furthermore, MVA-CHIKV elicited robust innate immune responses in human macrophages and monocyte-derived dendritic cells, with production of beta interferon (IFN-β), proinflammatory cytokines, and chemokines. After immunization of C57BL/6 mice with a homologous protocol (MVA-CHIKV/MVA-CHIKV), strong, broad, polyfunctional, and durable CHIKV-specific CD8+ T cell responses were elicited. The CHIKV-specific CD8+ T cells were preferentially directed against E1 and E2 proteins and, to a lesser extent, against C protein. CHIKV-specific CD8+ memory T cells of a mainly effector memory phenotype were also induced. The humoral arm of the immune system was significantly induced, as MVA-CHIKV elicited high titers of neutralizing antibodies against CHIKV. Remarkably, a single dose of MVA-CHIKV protected all mice after a high-dose challenge with CHIKV. In summary, MVA-CHIKV is an effective vaccine against chikungunya virus infection that induced strong, broad, highly polyfunctional, and long-lasting CHIKV-specific CD8+ T cell responses, together with neutralizing antibodies against CHIKV. These results support the consideration of MVA-CHIKV as a potential vaccine candidate against CHIKV. IMPORTANCE We have developed a novel vaccine candidate against chikungunya virus (CHIKV) based on the highly attenuated Poxvirus Vector modified vaccinia virus Ankara (MVA) expressing the CHIKV C, E3, E2, 6K, and E1 structural genes (termed MVA-CHIKV). Our findings revealed that MVA-CHIKV is a highly effective vaccine against chikungunya virus, with a single dose of the vaccine protecting all mice after a high-dose challenge with CHIKV. Furthermore, MVA-CHIKV is highly immunogenic, inducing strong innate responses: high, broad, polyfunctional, and long-lasting CHIKV-specific CD8+ T cell responses, together with neutralizing antibodies against CHIKV. This work provides a potential vaccine candidate against CHIKV.

Juan García-arriaza - One of the best experts on this subject based on the ideXlab platform.

  • Head-to-Head Comparison of Poxvirus NYVAC and ALVAC Vectors Expressing Identical HIV-1 Clade C Immunogens in Prime-Boost Combination with Env Protein in Nonhuman Primates
    Journal of virology, 2015
    Co-Authors: Juan García-arriaza, Xiaoying Shen, David C. Montefiori, Georgia D. Tomaras, Beatriz Perdiguero, Jonathan L. Heeney, Michael S. Seaman, Celia C. Labranche, Nicole L. Yates, Guido Ferrari
    Abstract:

    We compared the HIV-1-specific cellular and humoral immune responses elicited in rhesus macaques immunized with two Poxvirus Vectors (NYVAC and ALVAC) expressing the same HIV-1 antigens from clade C, Env gp140 as a trimeric cell-released protein and a Gag-Pol-Nef polyprotein as Gag-induced virus-like particles (VLPs) (referred to as NYVAC-C and ALVAC-C). The immunization protocol consisted of two doses of the corresponding Poxvirus Vector plus two doses of a combination of the Poxvirus Vector and a purified HIV-1 gp120 protein from clade C. This immunogenicity profile was also compared to that elicited by vaccine regimens consisting of two doses of the ALVAC Vector expressing HIV-1 antigens from clades B/E (ALVAC-vCP1521) plus two doses of a combination of ALVAC-vCP1521 and HIV-1 gp120 protein from clades B/E (similar to the RV144 trial regimen) or clade C. The results showed that immunization of macaques with NYVAC-C stimulated at different times more potent HIV-1-specific CD4+ T-cell responses and induced a trend toward higher-magnitude HIV-1-specific CD8+ T-cell immune responses than did ALVAC-C. Furthermore, NYVAC-C induced a trend toward higher levels of binding IgG antibodies against clade C HIV-1 gp140, gp120, or murine leukemia virus (MuLV) gp70-scaffolded V1/V2 and toward best cross-clade-binding IgG responses against HIV-1 gp140 from clades A, B, and group M consensus, than did ALVAC-C. Of the linear binding IgG responses, most were directed against the V3 loop in all immunization groups. Additionally, NYVAC-C and ALVAC-C also induced similar levels of HIV-1-neutralizing antibodies and antibody-dependent cellular cytotoxicity (ADCC) responses. Interestingly, binding IgA antibody levels against HIV-1 gp120 or MuLV gp70-scaffolded V1/V2 were absent or very low in all immunization groups. Overall, these results provide a comprehensive survey of the immunogenicity of NYVAC versus ALVAC expressing HIV-1 antigens in nonhuman primates and indicate that NYVAC may represent an alternative candidate to ALVAC in the development of a future HIV-1 vaccine. IMPORTANCE The finding of a safe and effective HIV/AIDS vaccine immunogen is one of the main research priorities. Here, we generated two Poxvirus-based HIV vaccine candidates (NYVAC and ALVAC Vectors) expressing the same clade C HIV-1 antigens in separate Vectors, and we analyzed in nonhuman primates their immunogenicity profiles. The results showed that immunization with NYVAC-C induced a trend toward higher HIV-1-specific cellular and humoral immune responses than did ALVAC-C, indicating that this new NYVAC Vector could be a novel optimized HIV/AIDS vaccine candidate for human clinical trials.

  • Kinetic and Phenotypic Analysis of CD8+ T Cell Responses after Priming with Alphavirus Replicons and Homologous or Heterologous Booster Immunizations
    Journal of Virology, 2014
    Co-Authors: Maria L. Knudsen, Karl Ljungberg, Maria Kakoulidou, Linda Kostic, David Hallengärd, Juan García-arriaza, Andres Merits, Mariano Esteban, Peter Liljeström
    Abstract:

    Alphavirus replicons are potent inducers of CD8+ T cell responses and thus constitute an attractive vaccine Vector platform for developing novel vaccines. However, the kinetics and memory phenotype of CD8+ T cell responses induced by alphavirus replicons are not well characterized. Furthermore, little is known how priming with alphavirus replicons affects booster immune responses induced by other vaccine modalities. We demonstrate here that a single immunization with an alphavirus replicon, administered as viral particles or naked DNA, induced an antigen-specific CD8+ T cell response that had a sharp peak, followed by a rapid contraction. Administering a homologous boost before contraction had occurred did not further increase the response. In contrast, boosting after contraction when CD8+ T cells had obtained a memory phenotype (based on CD127/CD62L expression), resulted in maintenance of CD8+ T cells with a high recall capacity (based on CD27/CD43 expression). Increasing the dose of replicon particles promoted T effector memory (Tem) and inhibited T central memory development. Moreover, infection with a replicating alphavirus induced a similar distribution of CD8+ T cells as the replicon Vector. Lastly, the distribution of T cell subpopulations induced by a DNA-launched alphavirus replicon could be altered by heterologous boosts. For instance, boosting with a Poxvirus Vector (MVA) favored expansion of the Tem compartment. In summary, we have characterized the antigen-specific CD8+ T cell response induced by alphavirus replicon Vectors and demonstrated how it can be altered by homologous and heterologous boost immunizations. IMPORTANCE Alphavirus replicons are promising vaccine candidates against a number of diseases and are by themselves developed as vaccines against, for example, Chikungunya virus infection. Replicons are also considered to be used for priming, followed by booster immunization using different vaccine modalities. In order to rationally design prime-boost immunization schedules with these Vectors, characterization of the magnitude and phenotype of CD8+ T cell responses induced by alphavirus replicons is needed. Here, we demonstrate how factors such as timing and dose affect the phenotypes of memory T cell populations induced by immunization with alphavirus replicons. These findings are important for designing future clinical trials with alphaviruses, since they can be used to tailor vaccination regimens in order to induce a CD8+ T cell response that is optimal for control and/or clearance of a specific pathogen.

  • Enhancing Poxvirus Vectors vaccine immunogenicity
    Human vaccines & immunotherapeutics, 2014
    Co-Authors: Juan García-arriaza, Mariano Esteban
    Abstract:

    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.

  • A Novel Poxvirus-based Vaccine (MVA-CHIKV) is Highly Immunogenic and Protects Mice against Chikungunya Infection
    Journal of virology, 2014
    Co-Authors: Juan García-arriaza, David Hallengärd, Peter Liljeström, Victoria Cepeda, Carlos Oscar S. Sorzano, Beate M. Kümmerer, Mariano Esteban
    Abstract:

    There is a need to develop a single and highly effective vaccine against the emerging chikungunya virus (CHIKV), which causes a severe disease in humans. Here, we have generated and characterized the immunogenicity profile and the efficacy of a novel CHIKV vaccine candidate based on the highly attenuated Poxvirus Vector modified vaccinia virus Ankara (MVA) expressing the CHIKV C, E3, E2, 6K, and E1 structural genes (termed MVA-CHIKV). MVA-CHIKV was stable in cell culture, expressed the CHIKV structural proteins, and triggered the cytoplasmic accumulation of Golgi apparatus-derived membranes in infected human cells. Furthermore, MVA-CHIKV elicited robust innate immune responses in human macrophages and monocyte-derived dendritic cells, with production of beta interferon (IFN-β), proinflammatory cytokines, and chemokines. After immunization of C57BL/6 mice with a homologous protocol (MVA-CHIKV/MVA-CHIKV), strong, broad, polyfunctional, and durable CHIKV-specific CD8+ T cell responses were elicited. The CHIKV-specific CD8+ T cells were preferentially directed against E1 and E2 proteins and, to a lesser extent, against C protein. CHIKV-specific CD8+ memory T cells of a mainly effector memory phenotype were also induced. The humoral arm of the immune system was significantly induced, as MVA-CHIKV elicited high titers of neutralizing antibodies against CHIKV. Remarkably, a single dose of MVA-CHIKV protected all mice after a high-dose challenge with CHIKV. In summary, MVA-CHIKV is an effective vaccine against chikungunya virus infection that induced strong, broad, highly polyfunctional, and long-lasting CHIKV-specific CD8+ T cell responses, together with neutralizing antibodies against CHIKV. These results support the consideration of MVA-CHIKV as a potential vaccine candidate against CHIKV. IMPORTANCE We have developed a novel vaccine candidate against chikungunya virus (CHIKV) based on the highly attenuated Poxvirus Vector modified vaccinia virus Ankara (MVA) expressing the CHIKV C, E3, E2, 6K, and E1 structural genes (termed MVA-CHIKV). Our findings revealed that MVA-CHIKV is a highly effective vaccine against chikungunya virus, with a single dose of the vaccine protecting all mice after a high-dose challenge with CHIKV. Furthermore, MVA-CHIKV is highly immunogenic, inducing strong innate responses: high, broad, polyfunctional, and long-lasting CHIKV-specific CD8+ T cell responses, together with neutralizing antibodies against CHIKV. This work provides a potential vaccine candidate against CHIKV.

  • Deletion of the vaccinia virus N2L gene encoding an inhibitor of IRF3 improves the immunogenicity of modified vaccinia virus Ankara expressing HIV-1 antigens.
    Journal of virology, 2014
    Co-Authors: Juan García-arriaza, Carlos Oscar S. Sorzano, Carmen E. Gómez, Mariano Esteban
    Abstract:

    ABSTRACT A modified vaccinia virus Ankara Poxvirus Vector expressing the HIV-1 Env, Gag, Pol, and Nef antigens from clade B (MVA-B) is currently being tested in clinical trials. To improve its immunogenicity, we have generated and characterized the immune profile of MVA-B containing a deletion of the vaccinia viral gene N2L , which codes for an inhibitor of IRF3 (MVA-B ΔN2L). Deletion of N2L had no effect on virus growth kinetics or on the expression of HIV-1 antigens; hence, the N2 protein is not essential for MVA replication. The innate immune responses triggered by MVA-B ΔN2L revealed an increase in beta interferon, proinflammatory cytokines, and chemokines. Mouse prime-boost protocols showed that MVA-B ΔN2L improves the magnitude and polyfunctionality of HIV-1-specific CD4 + and CD8 + T cell adaptive and memory immune responses, with most of the HIV-1 responses mediated by CD8 + T cells. In the memory phase, HIV-1-specific CD8 + T cells with an effector phenotype were predominant and in a higher percentage with MVA-B ΔN2L than with MVA-B. In both immunization groups, CD4 + and CD8 + T cell responses were directed mainly against Env. Furthermore, MVA-B ΔN2L in the memory phase enhanced levels of antibody against Env. For the Vector immune responses, MVA-B ΔN2L induced a greater magnitude and polyfunctionality of VACV-specific CD8 + T memory cells than MVA-B, with an effector phenotype. These results revealed the immunomodulatory role of N2L , whose deletion enhanced the innate immunity and improved the magnitude and quality of HIV-1-specific T cell adaptive and memory immune responses. These findings are relevant for the optimization of Poxvirus Vectors as vaccines. IMPORTANCE On the basis of the limited efficacy of the RV144 phase III clinical trial, new optimized Poxvirus Vectors as vaccines against HIV/AIDS are needed. Here we have generated and characterized a new HIV/AIDS vaccine candidate on the basis of the Poxvirus MVA Vector expressing HIV-1 Env, Gag, Pol, and Nef antigens (MVA-B) and containing a deletion in the vaccinia virus N2L gene. Our findings revealed the immunomodulatory role of N2L and proved that its deletion from the MVA-B Vector triggered an enhanced innate immune response in human macrophages and monocyte-derived dendritic cells. Furthermore, in immunized mice, MVA-B ΔN2L induced improvements in the magnitude and quality of adaptive and memory HIV-1-specific CD4 + and CD8 + T cell immune responses, together with an increase in the memory phase of levels of antibody against Env. Thus, the selective deletion of the N2L viral immunomodulatory gene is important for the optimization of MVA Vectors as HIV-1 vaccines.

Carmen E. Gómez - One of the best experts on this subject based on the ideXlab platform.

  • Deletion of the vaccinia virus N2L gene encoding an inhibitor of IRF3 improves the immunogenicity of modified vaccinia virus Ankara expressing HIV-1 antigens.
    Journal of virology, 2014
    Co-Authors: Juan García-arriaza, Carlos Oscar S. Sorzano, Carmen E. Gómez, Mariano Esteban
    Abstract:

    ABSTRACT A modified vaccinia virus Ankara Poxvirus Vector expressing the HIV-1 Env, Gag, Pol, and Nef antigens from clade B (MVA-B) is currently being tested in clinical trials. To improve its immunogenicity, we have generated and characterized the immune profile of MVA-B containing a deletion of the vaccinia viral gene N2L , which codes for an inhibitor of IRF3 (MVA-B ΔN2L). Deletion of N2L had no effect on virus growth kinetics or on the expression of HIV-1 antigens; hence, the N2 protein is not essential for MVA replication. The innate immune responses triggered by MVA-B ΔN2L revealed an increase in beta interferon, proinflammatory cytokines, and chemokines. Mouse prime-boost protocols showed that MVA-B ΔN2L improves the magnitude and polyfunctionality of HIV-1-specific CD4 + and CD8 + T cell adaptive and memory immune responses, with most of the HIV-1 responses mediated by CD8 + T cells. In the memory phase, HIV-1-specific CD8 + T cells with an effector phenotype were predominant and in a higher percentage with MVA-B ΔN2L than with MVA-B. In both immunization groups, CD4 + and CD8 + T cell responses were directed mainly against Env. Furthermore, MVA-B ΔN2L in the memory phase enhanced levels of antibody against Env. For the Vector immune responses, MVA-B ΔN2L induced a greater magnitude and polyfunctionality of VACV-specific CD8 + T memory cells than MVA-B, with an effector phenotype. These results revealed the immunomodulatory role of N2L , whose deletion enhanced the innate immunity and improved the magnitude and quality of HIV-1-specific T cell adaptive and memory immune responses. These findings are relevant for the optimization of Poxvirus Vectors as vaccines. IMPORTANCE On the basis of the limited efficacy of the RV144 phase III clinical trial, new optimized Poxvirus Vectors as vaccines against HIV/AIDS are needed. Here we have generated and characterized a new HIV/AIDS vaccine candidate on the basis of the Poxvirus MVA Vector expressing HIV-1 Env, Gag, Pol, and Nef antigens (MVA-B) and containing a deletion in the vaccinia virus N2L gene. Our findings revealed the immunomodulatory role of N2L and proved that its deletion from the MVA-B Vector triggered an enhanced innate immune response in human macrophages and monocyte-derived dendritic cells. Furthermore, in immunized mice, MVA-B ΔN2L induced improvements in the magnitude and quality of adaptive and memory HIV-1-specific CD4 + and CD8 + T cell immune responses, together with an increase in the memory phase of levels of antibody against Env. Thus, the selective deletion of the N2L viral immunomodulatory gene is important for the optimization of MVA Vectors as HIV-1 vaccines.

  • Poxvirus Vectors as HIV/AIDS vaccines in humans
    Human vaccines & immunotherapeutics, 2012
    Co-Authors: Carmen E. Gómez, Juan García-arriaza, Beatriz Perdiguero, Mariano Esteban
    Abstract:

    The RV144 phase III clinical trial with the combination of the Poxvirus Vector ALVAC and the HIV gp120 protein has taught us that a vaccine against HIV/AIDS is possible but further improvements are still needed. Although the HIV protective effect of RV144 was modest (31.2%), these encouraging results reinforce the use of Poxvirus Vectors as HIV/AIDS vaccine candidates. In this review we focus on the prophylactic clinical studies thus far performed with the more widely studied Poxvirus Vectors, ALVAC, MVA, NYVAC and fowlpox expressing HIV antigens. We describe the characteristics of each Vector administered either alone or in combination with other Vectors, with emphasis on the immune parameters evaluated in healthy volunteers, percentage of responders and triggering of humoral and T cell responses. Some of these immunogens induced broad, polyfunctional and long-lasting CD4+ and CD8+ T cell responses to HIV-1 antigens in most volunteers, with preference for effector memory T cells, and neutralizing antibodies, immune parameters that might be relevant in protection. Finally, we consider improvements in immunogenicity of the Poxvirus Vectors by the selective deletion of viral immunomodulatory genes and insertion of host range genes in the Poxvirus genome. Overall, the Poxvirus Vectors have proven to be excellent HIV/AIDS vaccine candidates, with distinct behavior among them, and the future implementation will be dictated by their optimized immune profile in clinical trials.

  • Vector replication and expression of hiv 1 antigens by the hiv aids vaccine candidate mva b is not affected by hiv 1 protease inhibitors
    Virus Research, 2012
    Co-Authors: Juan Garciaarriaza, Carmen E. Gómez, Pilar Arnaez, Jose L Jimenez, Maria Angeles Munozfernandez, Mariano Esteban
    Abstract:

    Abstract MVA-B is an attenuated Poxvirus Vector expressing human immunodeficiency virus type 1 Env, Gag, Pol, and Nef antigens from clade B, and is considered a promising HIV/AIDS vaccine candidate. Recently, a phase I clinical trial in human healthy volunteers has shown that MVA-B is safe and highly immunogenic, inducing broad, polyfunctional, and long-lasting CD4 + and CD8 + T cell responses to HIV-1 antigens, with preference for effector memory T cells; and it also triggers the induction of specific antibodies to Env in most of the vaccines. While MVA recombinants expressing HIV-1 antigens are being used or plan to use in therapeutic clinical trials, little is known on the effect of HIV-1 highly active antiretroviral therapy in MVA life cycle. To define this role, here we have evaluated in established cell cultures and human dendritic cells to what extent different HIV-1 protease inhibitors affect virus replication and expression of HIV-1 antigens during MVA-B infection. The results obtained revealed that the most commonly used HIV-1 protease inhibitors (atazanavir, ritonavir, and lopinavir) had no effect on MVA-B virus growth kinetics, even at higher concentrations than those normally used on HAART. Furthermore, expression of gp120 and the fused Gag-Pol-Nef polyprotein in permissive and non-permissive cells infected with MVA-B were also not affected. These findings are relevant information for the therapeutic use of MVA-B as an HIV-1/AIDS vaccine.

  • robust vaccine elicited cellular immune responses in breast milk following systemic simian immunodeficiency virus dna prime and live virus Vector boost vaccination of lactating rhesus monkeys
    Journal of Immunology, 2010
    Co-Authors: Andrew B Wilks, Mariano Esteban, Giuseppe Pantaleo, Michael S. Seaman, Carmen E. Gómez, Elizabeth C Christian, Piya Sircar, Angela Carville, Dan H Barouch, Norman L Letvin
    Abstract:

    Breast milk transmission of HIV remains an important mode of infant HIV acquisition. Enhancement of mucosal HIV-specific immune responses in milk of HIV-infected mothers through vaccination may reduce milk virus load or protect against virus transmission in the infant gastrointestinal tract. However, the ability of HIV/SIV strategies to induce virus-specific immune responses in milk has not been studied. In this study, five uninfected, hormone-induced lactating, Mamu A*01(+) female rhesus monkey were systemically primed and boosted with rDNA and the attenuated Poxvirus Vector, NYVAC, containing the SIVmac239 gag-pol and envelope genes. The monkeys were boosted a second time with a recombinant Adenovirus serotype 5 Vector containing matching immunogens. The vaccine-elicited immunodominant epitope-specific CD8(+) T lymphocyte response in milk was of similar or greater magnitude than that in blood and the vaginal tract but higher than that in the colon. Furthermore, the vaccine-elicited SIV Gag-specific CD4(+) and CD8(+) T lymphocyte polyfunctional cytokine responses were more robust in milk than in blood after each virus Vector boost. Finally, SIV envelope-specific IgG responses were detected in milk of all monkeys after vaccination, whereas an SIV envelope-specific IgA response was only detected in one vaccinated monkey. Importantly, only limited and transient increases in the proportion of activated or CCR5-expressing CD4(+) T lymphocytes in milk occurred after vaccination. Therefore, systemic DNA prime and virus Vector boost of lactating rhesus monkeys elicits potent virus-specific cellular and humoral immune responses in milk and may warrant further investigation as a strategy to impede breast milk transmission of HIV.

  • insertion of vaccinia virus c7l host range gene into nyvac b genome potentiates immune responses against hiv 1 antigens
    PLOS ONE, 2010
    Co-Authors: José Luis Nájera, Carmen E. Gómez, Juan Garciaarriaza, C O S Sorzano, Mariano Esteban
    Abstract:

    Background The highly attenuated vaccinia virus strain NYVAC expressing HIV-1 components has been evaluated as a vaccine candidate in preclinical and clinical trials with encouraging results. We have previously described that the presence of C7L in the NYVAC genome prevents the induction of apoptosis and renders the Vector capable of replication in human and murine cell lines while maintaining an attenuated phenotype in mice. Methodology/Principal Findings In an effort to improve the immunogenicity of NYVAC, we have developed a novel Poxvirus Vector by inserting the VACV host-range C7L gene into the genome of NYVAC-B, a recombinant virus that expresses four HIV-1 antigens from clade B (Env, Gag, Pol and Nef) (referred as NYVAC-B-C7L). In the present study, we have compared the in vitro and in vivo behavior of NYVAC-B and NYVAC-B-C7L. In cultured cells, NYVAC-B-C7L expresses higher levels of heterologous antigen than NYVAC-B as determined by Western blot and fluorescent-activated cell sorting to score Gag expressing cells. In a DNA prime/Poxvirus boost approach with BALB/c mice, both recombinants elicited robust, broad and multifunctional antigen-specific T-cell responses to the HIV-1 immunogens expressed from the Vectors. However, the use of NYVAC-B-C7L as booster significantly enhanced the magnitude of the T cell responses, and induced a more balanced cellular immune response to the HIV-1 antigens in comparison to that elicited in animals boosted with NYVAC-B. Conclusions/Significance These findings demonstrate the possibility to enhance the immunogenicity of the highly attenuated NYVAC Vector by the insertion of the host-range gene C7L and suggest the use of this modified Vector as an improved vaccine candidate against HIV/AIDS.

Qiao Zhou - One of the best experts on this subject based on the ideXlab platform.

  • Development of a multi-antigenic SARS-CoV-2 vaccine candidate using a synthetic Poxvirus platform
    Nature Communications, 2020
    Co-Authors: Flavia Chiuppesi, Heidi Contreras, Vu H. Nguyen, Joy Martinez, Jenny Nguyen, Mindy Kha, Angelina Iniguez, Marcela D’alincourt Salazar, Yoonsuh Park, Qiao Zhou
    Abstract:

    AbstractModified Vaccinia Ankara (MVA) is a highly attenuated Poxvirus Vector that is widely used to develop vaccines for infectious diseases and cancer. We demonstrate the construction of a vaccine platform based on a unique three-plasmid system to efficiently generate recombinant MVA Vectors from chemically synthesized DNA. In response to the ongoing global pandemic caused by SARS coronavirus-2 (SARS-CoV-2), we use this vaccine platform to rapidly produce fully synthetic MVA (sMVA) Vectors co-expressing SARS-CoV-2 spike and nucleocapsid antigens, two immunodominant antigens implicated in protective immunity. We show that mice immunized with these sMVA Vectors develop robust SARS-CoV-2 antigen-specific humoral and cellular immune responses, including potent neutralizing antibodies. These results demonstrate the potential of a vaccine platform based on synthetic DNA to efficiently generate recombinant MVA Vectors and to rapidly develop a multi-antigenic Poxvirus-based SARS-CoV-2 vaccine candidate.

  • Development of a Multi-Antigenic SARS-CoV-2 Vaccine Using a Synthetic Poxvirus Platform
    2020
    Co-Authors: Flavia Chiuppesi, Marcela Dâ Alincourt Salazar, Heidi Contreras, Vu H. Nguyen, Joy Martinez, Soojin Park, Jenny Nguyen, Mindy Kha, Angelina Iniguez, Qiao Zhou
    Abstract:

    Modified Vaccinia Ankara (MVA) is a highly attenuated Poxvirus Vector that is widely used to develop vaccines for infectious diseases and cancer. We developed a novel vaccine platform based on a unique three-plasmid system to efficiently generate recombinant MVA Vectors from chemically synthesized DNA. In response to the ongoing global pandemic caused by SARS coronavirus-2 (SARS-CoV-2), we used this novel vaccine platform to rapidly produce fully synthetic MVA (sMVA) Vectors co-expressing SARS-CoV-2 spike and nucleocapsid antigens, two immunodominant antigens implicated in protective immunity. Mice immunized with these sMVA Vectors developed robust SARS-CoV-2 antigen-specific humoral and cellular immune responses, including potent neutralizing antibodies. These results demonstrate the potential of a novel vaccine platform based on synthetic DNA to efficiently generate recombinant MVA Vectors and to rapidly develop a multi-antigenic Poxvirus-based SARS-CoV-2 vaccine candidate.

  • Development of a Synthetic Poxvirus-Based SARS-CoV-2 Vaccine
    bioRxiv : the preprint server for biology, 2020
    Co-Authors: Flavia Chiuppesi, Marcela Dâ Alincourt Salazar, Joy Martinez, Soojin Park, Jenny Nguyen, Mindy Kha, Angelina Iniguez, Nguyen Heidi, Qiao Zhou
    Abstract:

    Modified Vaccinia Ankara (MVA) is a highly attenuated Poxvirus Vector that is widely used to develop vaccines for infectious diseases and cancer We developed a novel vaccine platform based on a unique three-plasmid system to efficiently generate recombinant MVA Vectors from chemically synthesized DNA In response to the ongoing global pandemic caused by SARS coronavirus-2 (SARS-CoV-2), we used this novel vaccine platform to rapidly produce fully synthetic MVA (sMVA) Vectors co-expressing SARS-CoV-2 spike and nucleocapsid antigens, two immunodominant antigens implicated in protective immunity Mice immunized with these sMVA Vectors developed robust SARS-CoV-2 antigen-specific humoral and cellular immune responses, including potent neutralizing antibodies These results demonstrate the potential of a novel vaccine platform based on synthetic DNA to efficiently generate recombinant MVA Vectors and to rapidly develop a multi-antigenic Poxvirus-based SARS-CoV-2 vaccine candidate

James Tartaglia - One of the best experts on this subject based on the ideXlab platform.

  • Direct Comparison of Antigen Production and Induction of Apoptosis by Canarypox Virus- and Modified Vaccinia Virus Ankara-Human Immunodeficiency Virus Vaccine Vectors
    Journal of virology, 2007
    Co-Authors: Xiugen Zhang, James Tartaglia, Farah Cassis-ghavami, Mike Eller, Jeffrey R. Currier, Bonnie M. Slike, Xuemin Chen, Mary Marovich, Paul Spearman
    Abstract:

    Recombinant Poxvirus Vectors are undergoing intensive evaluation as vaccine candidates for a variety of infectious pathogens. AviPoxviruses, such as canarypox virus, are replication deficient in mammalian cells by virtue of a poorly understood species-specific restriction. Highly attenuated vaccinia virus strains such as modified vaccinia virus Ankara (MVA) are similarly unable to complete replication in most mammalian cells but have an abortive-late phenotype, in that the block to replication occurs post-virus-specific DNA replication. In this study, an identical expression cassette for human immunodeficiency virus gag, pro, and env coding sequences was placed in canarypox virus and MVA Vector backbones in order to directly compare Vector-borne expression and to analyze differences in Vector-host cell interactions. Antigen production by recombinant MVA was shown to be greater than that from recombinant canarypox virus in the mammalian cell lines and in the primary human cells tested. This observation was primarily due to a longer duration of antigen production in recombinant MVA-infected cells. Apoptosis induction was found to be more profound with the empty canarypox virus Vector than with MVA. Remarkably, however, the inclusion of a gag/pro/env expression cassette altered the kinetics of apoptosis induction in recombinant MVA-infected cells to levels equal to those found in canarypox virus-infected cells. Antigen production by MVA was noted to be greater in human dendritic cells and resulted in enhanced T-cell stimulation in an in vitro antigen presentation assay. These results reveal differences in Poxvirus Vector-host cell interactions that should be relevant to their use as immunization vehicles.

  • Human safety and immunogenicity of a canarypox-rabies glycoprotein recombinant vaccine: An alternative Poxvirus Vector system
    Vaccine, 1996
    Co-Authors: L. F. Fries, E. K. Kauffman, B. Meignier, Elena Paoletti, James Tartaglia, J. Taylor, Steven Plotkin
    Abstract:

    Avian Poxvirus recombinants undergo abortive replication in nonavian cells, yet can achieve expression of extrinsic gene products. Canarypox-Vectored vaccines have been innocuous and immunogenic in several mammalian species. ALVAC-RG, a canarypox recombinant expressing the rabies glycoprotein gene, was inoculated intramuscularly into adult volunteers on days 0, 28, and 180. Sequential cohorts received 103.5, 104.5, and 105.550% tissue culture infective doses (TCID50); additional volunteers received the standard human diploid cell rabies vaccine (HDCV) on the same schedule. Reactogenicity of ALVAC-RG was minimal. The lowest dose of ALVAC-RG induced little antibody to rabies virus by ELISA or rapid fluorescent focus inhibition test (RFFIT), but 104.5and 105.5TCID50doses elicited significant responses in both assays. All recipients of 104.5and 105.5TCID50of ALVAC-RG attained RFFIT values above the presumed protective level. Canarypox-specific immune responses did not inhibit boosting of rabies-specific antibodies by the day 180 dose of ALVAC-RG. T cell proliferation in response to inactivated rabies virus in vitro was similar in HDCV and ALVAC-RG recipients after the first and second doses, although HDCV yielded superior results after the third dose. ALVAC-RG was safe in humans, induced functional antibody to rabies glycoprotein, elicited cellular responses to rabies virtu, and could be used successfully for booster dosing at a 6 month interval.

  • highly attenuated hiv type 2 recombinant Poxviruses but not hiv 2 recombinant salmonella vaccines induce long lasting protection in rhesus macaques
    AIDS Research and Human Retroviruses, 1995
    Co-Authors: Genoveffa Franchini, James Tartaglia, Marjorie Robertguroff, Anita Aggarwal, Alashle Abimiku, John Benson, Phillip D Markham, Keith J Limbach, Greg Hurteau, Jake Fullen
    Abstract:

    Immunization schemes employing priming with Vector-based vaccine candidates followed by subunit booster administrations have been explored and shown to have merit in the human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus systems. In this study, we have assessed the priming capacity of highly attenuated Poxvirus Vector (NYVAC and ALVAC)-based HIV-2 recombinants, as well as Salmonella typhimurium HIV-2 recombinants in rhesus macaques. ALVAC- and NYVAC-based vaccine candidates expressing the HIV-2 gag, pol, and env genes or NYVAC-based recombinants expressing either gp160 or gp 120 were used to immunize rhesus macaques in combination protocols with alum-adjuvanted HIV-2 rgp160. Following intravenous challenge exposure with 100 infectious doses of the HIV-2SBL6669 parental virus genotype mixture, seven of eight animals were protected from infection. The seven protected animals were rechallenged 6 months postprimary challenge, without additional booster inoculations, with the same do...

  • Poxvirus-BASED VACCINE CANDIDATES FOR CANCER, AIDS, AND OTHER INFECTIOUS DISEASES
    Journal of leukocyte biology, 1995
    Co-Authors: Marion E. Perkus, James Tartaglia, Enzo Paoletti
    Abstract:

    Over the past 12 years, the Poxvirus Vector technology has provided scientists with valuable reagents to achieve high-level expression of proteins, to address questions of structure-function relationship of specific polypeptides, to investigate the immunobiology of specific pathogens, and to develop recombinant vaccine candidates. It is this last role that has drawn enthusiasm from the medical community because of the potential this technology has to provide novel approaches for addressing urgent needs in human and veterinary medicine. From one perspective, the safety issues surrounding the use of vaccinia-based vaccine candidates have been addressed with the development of the NYVAC and ALVAC Vectors. Evaluation of these novel Poxvirus Vectors are in progress to determine their potential impact on cancer and infectious disease.