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Breton, Marie, Chenqi Zhao, Marc Ouellette, Michel J. Tremblay et Barbara Papadopoulou. « A recombinant non-pathogenic Leishmania vaccine expressing human immunodeficiency virus 1 (HIV-1) Gag elicits cell-mediated immunity in mice and decreases HIV-1 replication in human tonsillar tissue following exposure to HIV-1 infection ». Journal of General Virology 88, no 1 (1 janvier 2007) : 217–25. http://dx.doi.org/10.1099/vir.0.81995-0.
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Live-vector human immunodeficiency virus (HIV) vaccines are an integral part of a number of HIV vaccine regimens currently under evaluation that have yielded promising results in pre-clinical testing. In this report, a non-pathogenic protozoan parasitic vector, Leishmania tarentolae, which shares common target cells with HIV-1, was used to express full-length HIV-1 Gag protein. Immunization of BALB/c mice with recombinant L. tarentolae led to the expansion of HIV-1 Gag-specific T cells and stimulated CD8+ T cells to produce gamma interferon in response to specific viral Gag epitopes. A booster immunization with recombinant L. tarentolae elicited effector memory HIV-1 Gag-specific CD4+ T lymphocytes and increased antibody titres against HIV-1 Gag. Most importantly, immunization of human tonsillar tissue cultured ex vivo with Gag-expressing L. tarentolae vaccine vector elicited a 75 % decrease in virus replication following exposure of the immunized tonsils to HIV-1 infection. These results demonstrated that recombinant L. tarentolae is capable of eliciting effective immune responses in mice and human systems, respectively, and suggest that this novel non-pathogenic recombinant vaccine vector shows excellent promise as a vaccination strategy against HIV-1.
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Lewis, Anne D., Ruju Chen, David C. Montefiori, Philip R. Johnson et K. Reed Clark. « Generation of Neutralizing Activity against Human Immunodeficiency Virus Type 1 in Serum by Antibody Gene Transfer ». Journal of Virology 76, no 17 (1 septembre 2002) : 8769–75. http://dx.doi.org/10.1128/jvi.76.17.8769-8775.2002.
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ABSTRACT Although several human immunodeficiency virus (HIV) vaccine approaches have elicited meaningful antigen-specific T-cell responses in animal models, no single vaccine candidate has engendered antibodies that broadly neutralize primary isolates of HIV type 1 (HIV-1). Thus, there remains a significant gap in the design of HIV vaccines. To address this issue, we exploited the existence of rare human monoclonal antibodies that have been isolated from HIV-infected individuals. Such antibodies neutralize a wide array of HIV-1 field isolates and have been shown to be effective in vivo. However, practical considerations preclude the use of antibody preparations as a prophylactic passive immunization strategy in large populations. Our concept calls for an antibody gene of choice to be transferred to muscle where the antibody molecule is synthesized and distributed to the circulatory system. In these experiments, we used a recombinant adeno-associated virus (rAAV) vector to deliver the gene for the human antibody IgG1b12 to mouse muscle. Significant levels of HIV-neutralizing activity were found in the sera of mice for over 6 months after a single intramuscular administration of the rAAV vector. This approach allows for predetermination of antibody affinity and specificity prior to “immunization” and avoids the need for an active humoral immune response against the HIV envelope protein.
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Martins, Sofia A., Joana Santos, Sandra Cabo Verde, João D. G. Correia et Rita Melo. « Construction of HER2-Specific HIV-1-Based VLPs ». Bioengineering 9, no 11 (19 novembre 2022) : 713. http://dx.doi.org/10.3390/bioengineering9110713.
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Virus-like particles (VLPs) are nanoplatforms comprised of one or more viral proteins with the capacity to self-assemble without viral genetic material. VLPs arise as promising nanoparticles (NPs) that can be exploited as vaccines, as drug delivery vehicles or as carriers of imaging agents. Engineered antibody constructs, namely single-chain variable fragments (scFv), have been explored as relevant molecules to direct NPs to their target. A vector containing the scFv of an antibody, aimed at the human epidermal growth factor receptor 2 (HER2) and fused to the human immunodeficiency virus (HIV) protein gp41, was previously constructed. The work herein describes the early results concerning the production and the characterization of HIV-1-based VLPs expressing this protein, which could function as potential non-toxic tools for transporting drugs and/or imaging agents.
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Saunders, Kevin O., Lingshu Wang, M. Gordon Joyce, Zhi-Yong Yang, Alejandro B. Balazs, Cheng Cheng, Sung-Youl Ko et al. « Broadly Neutralizing Human Immunodeficiency Virus Type 1 Antibody Gene Transfer Protects Nonhuman Primates from Mucosal Simian-Human Immunodeficiency Virus Infection ». Journal of Virology 89, no 16 (3 juin 2015) : 8334–45. http://dx.doi.org/10.1128/jvi.00908-15.
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ABSTRACTBroadly neutralizing antibodies (bnAbs) can prevent lentiviral infection in nonhuman primates and may slow the spread of human immunodeficiency virus type 1 (HIV-1). Although protection by passive transfer of human bnAbs has been demonstrated in monkeys, durable expression is essential for its broader use in humans. Gene-based expression of bnAbs provides a potential solution to this problem, although immune responses to the viral vector or to the antibody may limit its durability and efficacy. Here, we delivered an adeno-associated viral vector encoding a simianized form of a CD4bs bnAb, VRC07, and evaluated its immunogenicity and protective efficacy. The expressed antibody circulated in macaques for 16 weeks at levels up to 66 μg/ml, although immune suppression with cyclosporine (CsA) was needed to sustain expression. Gene-delivered simian VRC07 protected against simian-human immunodeficiency virus (SHIV) infection in monkeys 5.5 weeks after treatment. Gene transfer of an anti-HIV antibody can therefore protect against infection by viruses that cause AIDS in primates when the host immune responses are controlled.IMPORTANCESustained interventions that can prevent HIV-1 infection are needed to halt the spread of the HIV-1 pandemic. The protective capacity of anti-HIV antibody gene therapy has been established in mouse models of HIV-1 infection but has not been established for primates. We show here a proof-of-concept that gene transfer of anti-HIV antibody genes can protect against infection by viruses that cause AIDS in primates when host immune responses are controlled.
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Bresk, C., Tamara Hofer, Sarah Wilmschen, Marina Krismer, Anja Beierfuß, Grégory Effantin, Winfried Weissenhorn et al. « Induction of Tier 1 HIV Neutralizing Antibodies by Envelope Trimers Incorporated into a Replication Competent Vesicular Stomatitis Virus Vector ». Viruses 11, no 2 (15 février 2019) : 159. http://dx.doi.org/10.3390/v11020159.
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A chimeric vesicular stomatitis virus with the glycoprotein of the lymphocytic choriomeningitis virus, VSV-GP, is a potent viral vaccine vector that overcomes several of the limitations of wild-type VSV. Here, we evaluated the potential of VSV-GP as an HIV vaccine vector. We introduced genes for different variants of the HIV-1 envelope protein Env, i.e., secreted or membrane-anchored, intact or mutated furin cleavage site or different C-termini, into the genome of VSV-GP. We found that the addition of the Env antigen did not attenuate VSV-GP replication. All HIV-1 Env variants were expressed in VSV-GP infected cells and some were incorporated very efficiently into VSV-GP particles. Crucial epitopes for binding of broadly neutralizing antibodies against HIV-1 such as MPER (membrane-proximal external region), CD4 binding site, V1V2 and V3 loop were present on the surface of VSV-GP-Env particles. Binding of quaternary antibodies indicated a trimeric structure of VSV-GP incorporated Env. We detected high HIV-1 antibody titers in mice and showed that vectors expressing membrane-anchored Env elicited higher antibody titers than vectors that secreted Envs. In rabbits, Tier 1A HIV-1 neutralizing antibodies were detectable after prime immunization and titers further increased after boosting with a second immunization. Taken together, VSV-GP-Env is a promising vector vaccine against HIV-1 infection since this vector permits incorporation of native monomeric and/or trimeric HIV-1 Env into a viral membrane.
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Saunders, Kevin O., Sampa Santra, Robert Parks, Nicole L. Yates, Laura L. Sutherland, Richard M. Scearce, Harikrishnan Balachandran et al. « Immunogenicity of NYVAC Prime-Protein Boost Human Immunodeficiency Virus Type 1 Envelope Vaccination and Simian-Human Immunodeficiency Virus Challenge of Nonhuman Primates ». Journal of Virology 92, no 8 (7 février 2018) : e02035-17. http://dx.doi.org/10.1128/jvi.02035-17.
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ABSTRACTA preventive human immunodeficiency virus type 1 (HIV-1) vaccine is an essential part of the strategy to eradicate AIDS. A critical question is whether antibodies that do not neutralize primary isolate (tier 2) HIV-1 strains can protect from infection. In this study, we investigated the ability of an attenuated poxvirus vector (NYVAC) prime-envelope gp120 boost to elicit potentially protective antibody responses in a rhesus macaque model of mucosal simian-human immunodeficiency virus (SHIV) infection. NYVAC vector delivery of a group M consensus envelope, trivalent mosaic envelopes, or a natural clade B isolate B.1059 envelope elicited antibodies that mediated neutralization of tier 1 viruses, cellular cytotoxicity, and phagocytosis. None of the macaques made neutralizing antibodies against the tier 2 SHIV SF162P3 used for mucosal challenge. Significant protection from infection was not observed for the three groups of vaccinated macaques compared to unvaccinated macaques, although binding antibody to HIV-1 Env correlated with decreased viremia after challenge. Thus, NYVAC Env prime-gp120 boost vaccination elicited polyfunctional, nonneutralizing antibody responses with minimal protective activity against tier 2 SHIV mucosal challenge.IMPORTANCEThe antibody responses that confer protection against HIV-1 infection remain unknown. Polyfunctional antibody responses correlated with time to infection in previous macaque studies. Determining the ability of vaccines to induce these types of responses is critical for understanding how to improve upon the one efficacious human HIV-1 vaccine trial completed thus far. We characterized the antibody responses induced by a NYVAC-protein vaccine and determined the protective capacity of polyfunctional antibody responses in an R5, tier 2 mucosal SHIV infection model.
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Yu, Jae-Sung, James W. Peacock, Stacie Vanleeuwen, Tsungda Hsu, William R. Jacobs, Mark J. Cayabyab, Norman L. Letvin et al. « Generation of Mucosal Anti-Human Immunodeficiency Virus Type 1 T-Cell Responses by Recombinant Mycobacterium smegmatis▿ ». Clinical and Vaccine Immunology 13, no 11 (30 août 2006) : 1204–11. http://dx.doi.org/10.1128/cvi.00195-06.
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ABSTRACT A successful vaccine vector for human immunodeficiency virus type 1 (HIV-1) should induce anti-HIV-1 immune responses at mucosal sites. We have generated recombinant Mycobacterium smegmatis vectors that express the HIV-1 group M consensus envelope protein (Env) as a surface, intracellular, or secreted protein and have tested them in animals for induction of both anti-HIV-1 T-cell and antibody responses. Recombinant M. smegmatis engineered for expression of secreted protein induced optimal T-cell gamma interferon enzyme-linked immunospot assay responses to HIV-1 envelope in the spleen, female reproductive tract, and lungs. Unlike with the induction of T-cell responses, priming and boosting with recombinant M. smegmatis did not induce anti-HIV-1 envelope antibody responses, due primarily to insufficient protein expression of the insert. However, immunization with recombinant M. smegmatis expressing HIV-1 Env was able to prime for an HIV-1 Env protein boost for the induction of anti-HIV-1 antibody responses.
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Rose, Nina F., Anjeanette Roberts, Linda Buonocore et John K. Rose. « Glycoprotein Exchange Vectors Based on Vesicular Stomatitis Virus Allow Effective Boosting and Generation of Neutralizing Antibodies to a Primary Isolate of Human Immunodeficiency Virus Type 1 ». Journal of Virology 74, no 23 (1 décembre 2000) : 10903–10. http://dx.doi.org/10.1128/jvi.74.23.10903-10910.2000.
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ABSTRACT Live recombinant vesicular stomatitis viruses (VSVs) expressing foreign antigens are highly effective vaccine vectors. However, these vectors induce high-titer neutralizing antibody directed at the single VSV glycoprotein (G), and this antibody alone can prevent reinfection and boosting with the same vector. To determine if efficient boosting could be achieved by changing the G protein of the vector, we have developed two new recombinant VSV vectors based on the VSV Indiana serotype but with the G protein gene replaced with G genes from two other VSV serotypes, New Jersey and Chandipura. These G protein exchange vectors grew to titers equivalent to wild-type VSV and induced similar neutralizing titers to themselves but no cross-neutralizing antibodies to the other two serotypes. The effectiveness of these recombinant VSV vectors was illustrated in experiments in which sequential boosting of mice with the three vectors, all encoding the same primary human immunodeficiency virus (HIV) envelope protein, gave a fourfold increase in antibody titer to an oligomeric HIV envelope compared with the response in animals receiving the same vector three times. In addition, only the animals boosted with the exchange vectors produced antibodies neutralizing the autologous HIV primary isolate. These VSV envelope exchange vectors have potential as vaccines in immunizations when boosting of immune responses may be essential.
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Gonelli, Christopher A., Georges Khoury, Rob J. Center et Damian F. J. Purcell. « HIV-1-Based Virus-like Particles that Morphologically Resemble Mature, Infectious HIV-1 Virions ». Viruses 11, no 6 (2 juin 2019) : 507. http://dx.doi.org/10.3390/v11060507.
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A prophylactic vaccine eliciting both broad neutralizing antibodies (bNAbs) to the HIV-1 envelope glycoprotein (Env) and strong T cell responses would be optimal for preventing HIV-1 transmissions. Replication incompetent HIV-1 virus-like particles (VLPs) offer the opportunity to present authentic-structured, virion-associated Env to elicit bNAbs, and also stimulate T cell responses. Here, we optimize our DNA vaccine plasmids as VLP expression vectors for efficient Env incorporation and budding. The original vector that was used in human trials inefficiently produced VLPs, but maximized safety by inactivating RNA genome packaging, enzyme functions that are required for integration into the host genome, and deleting accessory proteins Vif, Vpr, and Nef. These original DNA vaccine vectors generated VLPs with incomplete protease-mediated cleavage of Gag and were irregularly sized. Mutations to restore function within the defective genes revealed that several of the reverse transcriptase (RT) deletions mediated this immature phenotype. Here, we made efficient budding, protease-processed, and mature-form VLPs that resembled infectious virions by introducing alternative mutations that completely removed the RT domain, but preserved most other safety mutations. These VLPs, either expressed from DNA vectors in vivo or purified after expression in vitro, are potentially useful immunogens that can be used to elicit antibody responses that target Env on fully infectious HIV-1 virions.
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Yu, Jae-Sung, James W. Peacock, William R. Jacobs, Richard Frothingham, Norman L. Letvin, Hua-Xin Liao et Barton F. Haynes. « Recombinant Mycobacterium bovis Bacillus Calmette-Guérin Elicits Human Immunodeficiency Virus Type 1 Envelope-Specific T Lymphocytes at Mucosal Sites ». Clinical and Vaccine Immunology 14, no 7 (16 mai 2007) : 886–93. http://dx.doi.org/10.1128/cvi.00407-06.
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ABSTRACT A successful vaccine vector for human immunodeficiency virus type 1 (HIV-1) should induce anti-HIV-1 T-cell immune responses at mucosal sites. We have constructed recombinant Mycobacterium bovis bacillus Calmette-Guérin (rBCG) expressing an HIV-1 group M consensus envelope (Env) either as a surface, intracellular, or secreted protein as an immunogen. rBCG containing HIV-1 env plasmids engineered for secretion induced optimal Env-specific T-cell gamma interferon enzyme-linked immunospot responses in murine spleen, female reproductive tract, and lungs. While rBCG-induced T-cell responses to HIV-1 envelope in spleen were lower than those induced by adenovirus prime/recombinant vaccinia virus (rAd-rVV) boost, rBCG induced comparable responses to rAd-rVV immunization in the female reproductive tract and lungs. T-cell responses induced by rBCG were primarily CD4+, although rBCG alone did not induce anti-HIV-1 antibody. However, rBCG could prime for a protein boost by HIV-1 envelope protein. Thus, rBCG can serve as a vector for induction of anti-HIV-1 consensus Env cellular responses at mucosal sites.
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Jin, Hongliang, Xiaoran Tang, Li Li, Yue Chen, Yuanmei Zhu, Huihui Chong et Yuxian He. « Generation of HIV-resistant cells with a single-domain antibody : implications for HIV-1 gene therapy ». Cellular & ; Molecular Immunology 18, no 3 (18 janvier 2021) : 660–74. http://dx.doi.org/10.1038/s41423-020-00627-y.
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AbstractThe cure or functional cure of the “Berlin patient” and “London patient” indicates that infusion of HIV-resistant cells could be a viable treatment strategy. Very recently, we genetically linked a short-peptide fusion inhibitor with a glycosylphosphatidylinositol (GPI) attachment signal, rendering modified cells fully resistant to HIV infection. In this study, GPI-anchored m36.4, a single-domain antibody (nanobody) targeting the coreceptor-binding site of gp120, was constructed with a lentiviral vector. We verified that m36.4 was efficiently expressed on the plasma membrane of transduced TZM-bl cells and targeted lipid raft sites without affecting the expression of HIV receptors (CD4, CCR5, and CXCR4). Significantly, TZM-bl cells expressing GPI-m36.4 were highly resistant to infection with divergent HIV-1 subtypes and potently blocked HIV-1 envelope-mediated cell-cell fusion and cell-cell viral transmission. Furthermore, we showed that GPI-m36.4-modified human CEMss-CCR5 cells were nonpermissive to both CCR5- and CXCR4-tropic HIV-1 isolates and displayed a strong survival advantage over unmodified cells. It was found that GPI-m36.4 could also impair HIV-1 Env processing and viral infectivity in transduced cells, underlying a multifaceted mechanism of antiviral action. In conclusion, our studies characterize m36.4 as a powerful nanobody that can generate HIV-resistant cells, offering a novel gene therapy approach that can be used alone or in combination.
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sangare, Kotou, Christopher Hogge, Sabrina Helmold Hait, Tanya Hoang, Marjorie Robert-Guroff et A. Thomas Michael. « HIV-1-specific B cell immune responses in Rhesus Macaques induced by early region deleted-Ad5 vectors ». Journal of Immunology 202, no 1_Supplement (1 mai 2019) : 72.1. http://dx.doi.org/10.4049/jimmunol.202.supp.72.1.
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Abstract As a vaccine delivery vector, Adenovirus (Ad) is recognized for its ability to prime immune responses against HIV and other infectious agents. We reported that early region 1B55k (E1B55k) deleted vector induced cellular immunity, transgene-specific antibodies and innate immune signals including chemokines, cytokines and NKG2D ligands MIC A/B in immunized mice. However, the immune priming ability of E3-E1B55k-E4orf1 and E3-E1B55k- E4orf1-4deleted Ad vectors is unknown. Here we compared HIV-specific immune responses generated by E3deleted, E3-E1B55k, E3-E1B55k-E4orf1and E3-E1B55k-E4orf1-4deleted Ad5 vectors encoding full-length single-chain HIVBalgp120 linked to the D1 and D2 domains of rhesus macaque (RM) CD4 (rhFLSC). RMs were immunized twice mucosally with each vector. Blood and rectal tissue were collected at pre and 2-week post-immunization time points. The frequency of plasmablasts (PB)/plasma cells (PC), memory B cells, and antibody secreting cells and antibody titers were assessed by flow cytometry, ELISpot and ELISA, respectively. All vectors induced increased frequencies of rectal PB, PC and rhFLSC specific memory B cells. rhFLSC specific IgA and IgG secreting cells were detected in all immunized macaques; the IgA secreting cells were significantly increased compared to pre values. This was accompanied by elevated levels of IgG, IgG1 and IgA serum antibodies. In summary all four vectors induced B cells responses while retaining replicability. Moreover, the largest deletion, E3-E1B55k-E4orf1-4, improved the transgene carrying capacity of the Ad vector while maintaining the ability to induce B cell immunity important for protective efficacy.
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García-Arriaza, Juan, Beatriz Perdiguero, Jonathan Heeney, Michael Seaman, David C. Montefiori, Celia Labranche, Nicole L. Yates et al. « 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 89, no 16 (3 juin 2015) : 8525–39. http://dx.doi.org/10.1128/jvi.01265-15.
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ABSTRACTWe 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.IMPORTANCEThe 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.
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Forsell, Mattias N. E., Yuxing Li, Maria Sundbäck, Krisha Svehla, Peter Liljeström, John R. Mascola, Richard Wyatt et Gunilla B. Karlsson Hedestam. « Biochemical and Immunogenic Characterization of Soluble Human Immunodeficiency Virus Type 1 Envelope Glycoprotein Trimers Expressed by Semliki Forest Virus ». Journal of Virology 79, no 17 (1 septembre 2005) : 10902–14. http://dx.doi.org/10.1128/jvi.79.17.10902-10914.2005.
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ABSTRACT The current lack of envelope glycoprotein immunogens that elicit broadly neutralizing antibody responses remains a major challenge for human immunodeficiency virus type 1 (HIV-1) vaccine development. However, the recent design and construction of stable soluble gp140 trimers have shown that some neutralization breadth can be achieved by using immunogens that better mimic the functional viral spike complex. The use of genetic delivery systems to drive the in vivo expression of such immunogens for the stimulation of neutralizing antibodies against HIV-1 may offer advantages by maintaining the quaternary structure of the trimeric envelope glycoproteins. Here, we describe the biochemical and immunogenic properties of soluble HIV-1 envelope glycoprotein trimers expressed by recombinant Semliki Forest virus (rSFV). The results presented here demonstrate that rSFV supports the expression of stable soluble gp140 trimers that retain recognition by conformationally sensitive antibodies. Further, we show that rSFV particle immunizations efficiently primed immune responses as measured after a single boost with purified trimeric gp140 protein, resulting in a Th1-biased antibody response. This differed from the Th2-biased antibody response obtained after repeated immunizations with purified gp140 protein trimers. Despite this difference, both regimens stimulated neutralizing antibody responses of similar potency. This suggests that rSFV may be a useful component of a viral vector prime-protein boost regimen aimed at stimulating both cell-mediated immune responses and neutralizing antibodies against HIV-1.
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Tewari, Deepanker, Simoy L. Goldstein, Abner L. Notkins et Paul Zhou. « cDNA Encoding a Single-Chain Antibody to HIV p17 with Cytoplasmic or Nuclear Retention Signals Inhibits HIV-1 Replication ». Journal of Immunology 161, no 5 (1 septembre 1998) : 2642–47. http://dx.doi.org/10.4049/jimmunol.161.5.2642.
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Abstract HIV-1 gag p17 protein is an attractive target for molecular intervention, because it is involved in the viral replication cycle at both the pre- and postintegration levels. In the present experiments, we targeted p17 by intracellularly expressing a cDNA encoding an Ab to p17. cDNA from a hybridoma-secreting Ab to p17 was cloned, sequenced, reconstructed as a single-chain Ab fragment (scFv), and expressed in the cytoplasm or nucleus with appropriate retention signals. The expressed scFvs had no effect on T cell growth or CD4 expression and bound specifically to HIV-1 p17. Human CD4+ Jurkat T cells that expressed scFvs and were infected with HIV-1 showed a marked reduction in virus replication compared with cells expressing vector alone. The inhibition of virus replication was more pronounced when scFvs were expressed in the cytoplasm rather than the nucleus. From these studies, we conclude that the intracellular expression of a single-chain Ab to p17 inhibits HIV replication; in addition, the degree of inhibition is related to the intracellular targeting site.
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Garcia-Bates, Tatiana M., Eun Kim, Andrea Gambotto, Charles R. Rinaldo et Robbie B. Mailliard. « PD-1 inhibition results in reduced dendritic cell (DC) activation of HIV-1-specific de novo CTL and enhancement of DC-induced CTL memory recall responses ». Journal of Immunology 196, no 1_Supplement (1 mai 2016) : 148.8. http://dx.doi.org/10.4049/jimmunol.196.supp.148.8.
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Abstract Combination strategies consisting of DC vaccines and suppression of immunoregulatory pathways such as PD-1 blockade have been advocated to elicit optimal CTL responses in chronic diseases including cancer and HIV infection. We have shown that inactivated HIV-1 virus loaded, high IL-12 producing, mature, type-1 polarized DC (DC1) can activate CTL from naïve CD8+ T cell precursors that more effectively kill HIV-1-infected cells than CTL derived from memory CD8+ T cells. Here we tested DC1 transfected with an adenoviral (Ad) vector encoding anti-PD-1 antibody (DC.αPD1) enhancement of both primary as well as memory CTL responses to HIV-1. Ad-αPD1-transduced DC1 (DC.αPD1) secreted high levels of functional anti-PD1 Ab without affecting their phenotype or IL-12p70-producing capacity. We next compared HIV Gag peptide epitope-loaded DC.αPD1 to DC1 that were transfected with an empty vector for their ability to activate either purified, autologous naïve or memory HIV-1-specific CD8+ T cells from chronic HIV-1-infected participants of the Multicenter AIDS Cohort Study. When compared to the control DC1, antigen-loaded DC.αPD1 enhanced the overall magnitude of HIV-1-specific CTL responses induced, as determined by the expansion of HIV-1-peptide responsive CD107a and IFNγ expressing T cells. In contrast, the overall number HIV-1 antigen-reactive CTL derived from the naïve CD8+ T cell fraction sharply decreased when using the DC.αPD1-based approach. These results suggest previously unrecognized, opposing roles of the inhibitory receptor PD-1 in DC1-induced primary versus memory recall CD8+ T cell responses to HIV-1.
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Hamorsky, Krystal Teasley, Tiffany W. Grooms-Williams, Adam S. Husk, Lauren J. Bennett, Kenneth E. Palmer et Nobuyuki Matoba. « Efficient Single Tobamoviral Vector-Based Bioproduction of Broadly Neutralizing Anti-HIV-1 Monoclonal Antibody VRC01 in Nicotiana benthamiana Plants and Utility of VRC01 in Combination Microbicides ». Antimicrobial Agents and Chemotherapy 57, no 5 (12 février 2013) : 2076–86. http://dx.doi.org/10.1128/aac.02588-12.
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ABSTRACTBroadly neutralizing monoclonal antibodies (bnMAbs) may offer powerful tools for HIV-1 preexposure prophylaxis, such as topical microbicides. However, this option is hampered due to expensive MAb biomanufacturing based on mammalian cell culture. To address this issue, we developed a new production system for bnMAb VRC01 inNicotiana benthamianaplants using a tobamovirus replicon vector. Unlike conventional two-vector-based expression, this system was designed to overexpress full-length IgG1 from a single polypeptide by means of kex2p-like enzyme recognition sites introduced between the heavy and light chains. An enzyme-linked immunosorbent assay (ELISA) revealed that gp120-binding VRC01 IgG1 was maximally accumulated on 5 to 7 days following vector inoculation, yielding ∼150 mg of the bnMAb per kg of fresh leaf material. The plant-made VRC01 (VRC01p) was efficiently purified by protein A affinity followed by hydrophobic-interaction chromatography. ELISA, surface plasmon resonance, and an HIV-1 neutralization assay demonstrated that VRC01p has gp120-binding affinity and HIV-1-neutralization capacity virtually identical to the human-cell-produced counterpart. To advance VRC01p's use in topical microbicides, we analyzed combinations of the bnMAb with other microbicide candidates holding distinct antiviral mechanisms in an HIV-1 neutralization assay. VRC01p exhibited clear synergy with the antiviral lectin griffithsin, the CCR5 antagonist maraviroc, and the reverse transcriptase inhibitor tenofovir in multiple CCR5-tropic HIV-1 strains from clades A, B, and C. In summary, VRC01p is amenable to robust, rapid, and large-scale production and may be developed as an active component in combination microbicides with other anti-HIV agents such as antiviral lectins, CCR5 antagonists, and reverse transcriptase inhibitors.
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Yonezawa, Akihito, Toshiyuki Hori, Akifumi Takaori-Kondo, Rinpei Morita et Takashi Uchiyama. « Replacement of the V3 Region of gp120 with SDF-1 Preserves the Infectivity of T-Cell Line-Tropic Human Immunodeficiency Virus Type 1 ». Journal of Virology 75, no 9 (1 mai 2001) : 4258–67. http://dx.doi.org/10.1128/jvi.75.9.4258-4267.2001.
Texte intégralRésumé :
ABSTRACT Interaction between the human immunodeficiency virus type 1 (HIV-1) envelope and the relevant chemokine receptors is crucial for subsequent membrane fusion and viral entry. Although the V3 region of gp120 is known to determine the cell tropism as well as the coreceptor usage, the significance of the binding of the V3 region to the chemokine receptor has not been fully understood. To address this issue, we adopted the pseudotyped virus infection assay in which the V3 region of the T-cell line-tropic (T-tropic) NL4-3 envelope was replaced with a portion of stromal cell-derived factor 1 (SDF-1), the ligand of CXCR4. The V3 region of the NL4-3 envelope expression vector was replaced with three different stretches of SDF-1 cDNA. Expression of each chimeric envelope protein was confirmed by immunoprecipitation and Western blotting. Luciferase reporter viruses were prepared by cotransfection of the pNL4-3.Luc.E−R− vector and each chimeric envelope expression vector, and the infection assay was then carried out. We showed that pseudotyped viruses with one of the chimeric envelopes, NL4-3/SDF1-51, could infect U87.CD4.CXCR4 but not U87.CD4 or U87.CXCR4 cells and that this infection was inhibited by the ligand of CXCR4, SDF-1β, by anti-human SDF-1 antibody, or by an anti-CD4 antibody, Leu3a, in a dose-dependent manner. Furthermore, chimeric NL4-3/SDF1-51 gp120 significantly inhibited binding of labeled SDF-1 to CXCR4. It was suggested that replacement of the V3 region of the NL4-3 envelope with SDF-1 preserved the CD4-dependent infectivity of T-tropic HIV-1. These results indicate that binding between the V3 region and the relevant coreceptor is important for viral entry, whether its amino acid sequence is indigenous to the virus or not.
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Paszkiet, Brian, Andrew Worden, Yajin Ni, Saran Bao, Franck Lemiale, Boro Dropulic et Laurent Humeau. « CD86 and CD54 Co-Expression on VSV-G Pseudotyped HIV-1 Based Vectors Improves Transduction and Activation of Human Primary CD4+ T Lymphocytes. » Blood 104, no 11 (16 novembre 2004) : 1754. http://dx.doi.org/10.1182/blood.v104.11.1754.1754.
Texte intégralRésumé :
Abstract We established the first clinical ex vivo HIV-based vector gene therapy trial in humans with HIV+ CD4+ T-cells. Briefly, this therapy involves modifying patient CD4+ T-cells with our modified lentiviral vector carrying an anti-HIV payload. These cells are then activated and expanded, and re-infused back into the patient. However, cGMP regulations require the use of costly clinical grade reagents (i.e. Retronectin™, CD3/CD28 stimulating paramagnetic beads). In an attempt to reduce ex-vivo processing costs, but not at the expense of transduction levels, we sought to determine a way to directly activate CD4+ T-cells with modified lentiviral vectors. 293FT HEK cell lines, used for producing our lentiviral vectors, were modified to co-express the natural CD28 stimulatory ligand B7.2 (CD86) and ICAM-1 (CD54) proteins on their membrane for co-stimulation and anchoring purposes. When CliniMACS purified normal donor CD4+ T cells were co-cultured with CD54/CD86-expressing cells, in the presence of soluble OKT3 CD3 antibody, CD25 and CD69 activation markers were upregulated, indicating that functional proteins were being expressed at the cell membrane. These CD54 and/or CD86 expressing cells could subsequently be transfected with lentiviral vector plasmid constructs in order to produce host-derived CD54 and/or CD86 bearing HIV-based vectors. EGFP-expressing lentiviral vectors, VRX494, with CD54/CD86-modified envelopes were produced both in these cell lines and by transient transfection of all relevant plasmids, and titers were assayed on Hela-Tat cells by FACS. CD54 modified lentiviral vectors showed increased binding to CD4+ T-cells, as evidenced by significant cell clumping. CD86 (as well as CD54 plus CD86) modified lentiviral vector, with soluble OKT3 CD3 antibody, was shown to activate T-cells, above the levels seen with unmodified lentiviral vectors, as evidenced by the increase in cell surface CD25 and CD69 expression and also the increase in cell size. Cellular expansion of modified lentiviral vector transduced CD4+ T cells reached levels close to CD3:CD28 bead stimulated CD4+ T cell controls over a period of 2 to 3 weeks. The CD3/TCR repertoire was assessed by flow cytometry and, compared to the well-established CD3/CD28 coated M450 Dynabeads stimulatory system as a control, no skewing of the repertoire was observed. CD86 was shown to improve levels of transduction in pre-activated lymphocytes with CD3/CD28 coated M450 Dynabeads. However, CD86 co-expression was crucial for transducing minimally activated CD4+ T cells with only soluble OKT3 CD3 antibody. Levels of transduction and activation were on average 2 to 3 times higher with the modified lentiviral vectors. To our knowledge, we are reporting the first generation of lentiviral particles exhibiting an adhesion property with stimulatory abilities. The development of such a lentiviral vector has valuable implications for clinical application by reducing the number of exogenous reagents in large scale cell processing.
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Hulot, Sandrine L., Bette Korber, Elena E. Giorgi, Nathan Vandergrift, Kevin O. Saunders, Harikrishnan Balachandran, Linh V. Mach et al. « Comparison of Immunogenicity in Rhesus Macaques of Transmitted-Founder, HIV-1 Group M Consensus, and Trivalent Mosaic Envelope Vaccines Formulated as a DNA Prime, NYVAC, and Envelope Protein Boost ». Journal of Virology 89, no 12 (8 avril 2015) : 6462–80. http://dx.doi.org/10.1128/jvi.00383-15.
Texte intégralRésumé :
ABSTRACTAn effective human immunodeficiency virus type 1 (HIV-1) vaccine must induce protective antibody responses, as well as CD4+and CD8+T cell responses, that can be effective despite extraordinary diversity of HIV-1. The consensus and mosaic immunogens are complete but artificial proteins, computationally designed to elicit immune responses with improved cross-reactive breadth, to attempt to overcome the challenge of global HIV diversity. In this study, we have compared the immunogenicity of a transmitted-founder (T/F) B clade Env (B.1059), a global group M consensus Env (Con-S), and a global trivalent mosaic Env protein in rhesus macaques. These antigens were delivered using a DNA prime-recombinant NYVAC (rNYVAC) vector and Env protein boost vaccination strategy. While Con-S Env was a single sequence, mosaic immunogens were a set of three Envs optimized to include the most common forms of potential T cell epitopes. Both Con-S and mosaic sequences retained common amino acids encompassed by both antibody and T cell epitopes and were central to globally circulating strains. Mosaics and Con-S Envs expressed as full-length proteins bound well to a number of neutralizing antibodies with discontinuous epitopes. Also, both consensus and mosaic immunogens induced significantly higher gamma interferon (IFN-γ) enzyme-linked immunosorbent spot assay (ELISpot) responses than B.1059 immunogen. Immunization with these proteins, particularly Con-S, also induced significantly higher neutralizing antibodies to viruses than B.1059 Env, primarily to tier 1 viruses. Both Con-S and mosaics stimulated more potent CD8-T cell responses against heterologous Envs than did B.1059. Both antibody and cellular data from this study strengthen the concept of usingin silico-designed centralized immunogens for global HIV-1 vaccine development strategies.IMPORTANCEThere is an increasing appreciation for the importance of vaccine-induced anti-Env antibody responses for preventing HIV-1 acquisition. This nonhuman primate study demonstrates thatin silico-designed global HIV-1 immunogens, designed for a human clinical trial, are capable of eliciting not only T lymphocyte responses but also potent anti-Env antibody responses.
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Kent, Stephen J., Anne Zhao, Susan J. Best, Jenalle D. Chandler, David B. Boyle et Ian A. Ramshaw. « Enhanced T-Cell Immunogenicity and Protective Efficacy of a Human Immunodeficiency Virus Type 1 Vaccine Regimen Consisting of Consecutive Priming with DNA and Boosting with Recombinant Fowlpox Virus ». Journal of Virology 72, no 12 (1 décembre 1998) : 10180–88. http://dx.doi.org/10.1128/jvi.72.12.10180-10188.1998.
Texte intégralRésumé :
ABSTRACT The induction of human immunodeficiency virus (HIV)-specific T-cell responses is widely seen as critical to the development of effective immunity to HIV type 1 (HIV-1). Plasmid DNA and recombinant fowlpox virus (rFPV) vaccines are among the most promising safe HIV-1 vaccine candidates. However, the immunity induced by either vaccine alone may be insufficient to provide durable protection against HIV-1 infection. We evaluated a consecutive immunization strategy involving priming with DNA and boosting with rFPV vaccines encoding common HIV-1 antigens. In mice, this approach induced greater HIV-1-specific immunity than either vector alone and protected mice from challenge with a recombinant vaccinia virus expressing HIV-1 antigens. In macaques, a dramatic boosting effect on DNA vaccine-primed HIV-1-specific helper and cytotoxic T-lymphocyte responses, but a decline in HIV-1 antibody titers, was observed following rFPV immunization. The vaccine regimen protected macaques from an intravenous HIV-1 challenge, with the resistance most likely mediated by T-cell responses. These studies suggest a safe strategy for the enhanced generation of T-cell-mediated protective immunity to HIV-1.
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Buffa, Viviana, Donatella R. M. Negri, Pasqualina Leone, Roberta Bona, Martina Borghi, Ilaria Bacigalupo, Davide Carlei, Cecilia Sgadari, Barbara Ensoli et Andrea Cara. « A single administration of lentiviral vectors expressing either full-length human immunodeficiency virus 1 (HIV-1)HXB2 Rev/Env or codon-optimized HIV-1JR-FL gp120 generates durable immune responses in mice ». Journal of General Virology 87, no 6 (1 juin 2006) : 1625–34. http://dx.doi.org/10.1099/vir.0.81706-0.
Texte intégralRésumé :
Genetic immunization using viral vectors provides an effective means to elicit antigen-specific cellular immune responses. Several viral vectors have proven efficacious in inducing immune responses after direct injection in vivo. Among them, recombinant, self-inactivating lentiviral vectors are very attractive delivery systems, as they are able to efficiently transduce into and express foreign genes in a wide variety of mammalian cells. A self-inactivating lentiviral vector was evaluated for the delivery of human immunodeficiency virus 1 (HIV-1) envelope sequences in mice in order to elicit specific immune responses. With this aim, BALB/c mice were immunized with a single injection of self-inactivating lentiviral vectors carrying either the full-length HIV-1HXB2 Rev/Env (TY2-IIIBEnv) or the codon-optimized HIV-1JR-FL gp120 (TY2-JREnv) coding sequence. Both vectors were able to elicit specific cellular responses efficiently, as measured by gamma interferon ELISPOT and chromium-release assays, upon in vitro stimulation of splenocytes from BALB/c immunized mice. However, only the TY2-JREnv-immunized mice were able to elicit specific humoral responses, measured as anti-gp120 antibody production. These data provide the first evidence that a single, direct, in vivo administration of a lentiviral vector encoding a viral gene might represent a useful strategy for vaccine development.
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Liang, Xiaoping, Danilo R. Casimiro, William A. Schleif, Fubao Wang, Mary-Ellen Davies, Zhi-Qiang Zhang, Tong-Ming Fu et al. « Vectored Gag and Env but Not Tat Show Efficacy against Simian-Human Immunodeficiency Virus 89.6P Challenge in Mamu-A*01-Negative Rhesus Monkeys ». Journal of Virology 79, no 19 (1 octobre 2005) : 12321–31. http://dx.doi.org/10.1128/jvi.79.19.12321-12331.2005.
Texte intégralRésumé :
ABSTRACT Simian-human immunodeficiency virus (SHIV) challenge studies in rhesus macaques were conducted to evaluate the efficacy of adenovirus-based vaccines in the context of different major histocompatibility complex class I genetic backgrounds and different vaccine compositions. Mamu-A *01 allele-negative rhesus monkeys were immunized with one of the following vaccine constructs: (i) replication-defective recombinant adenovirus type 5 (Ad5) expressing human immunodeficiency virus type 1 (HIV-1) Tat (Ad5/HIVTat); (ii) Ad5 vector expressing simian immunodeficiency virus (SIV) Gag (Ad5/SIVGag); (iii) Ad5 vector expressing the truncated HIV-1jrfl Env, gp140 (Ad5/gp140_jrfl); (iv) Ad5 vector expressing the SHIV-89.6P gp140 (Ad5/gp140_89.6P); or (v) the combination of Ad5/SIVGag and Ad5/gp140_jrfl. Following intravenous challenge with SHIV-89.6P, only those cohorts that received vaccines expressing Gag or Env exhibited an attenuation of the acute viremia and associated CD4-cell lymphopenia. While no prechallenge neutralizing antibody titers were detectable in either Ad5/gp140-vaccinated group, an accelerated neutralizing antibody response was observed in the Ad5/gp140_89.6P-vaccinated group upon viral challenge. The set-point viral loads in the Ad5/SIVGag- and Ad5/gp140_jrfl-vaccinated groups were associated with the overall strength of the induced cellular immune responses. To examine the contribution of Mamu-A *01 allele in vaccine efficacy against SHIV-89.6P challenge, Mamu-A*01-positive monkeys were immunized with Ad5/SIVGag. Vaccine-mediated protection was significantly more pronounced in the Mamu-A*01-positive monkeys than in Mamu-A*01-negative monkeys, suggesting the strong contributions of T-cell epitopes restricted by the Mamu-A*01 molecule. The implications of these results in the development of an HIV-1 vaccine will be discussed.
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Anand, Appakkudal R., et Ramesh K. Ganju. « Akt Regulates the Activation-Induced Apoptosis of T Cells Mediated by HIV-1 gp120. » Blood 104, no 11 (16 novembre 2004) : 3109. http://dx.doi.org/10.1182/blood.v104.11.3109.3109.
Texte intégralRésumé :
Abstract Multiple mechanisms contribute to the loss of CD4+ T cells in HIV-1 infected individuals. Activation-induced apoptosis of bystander T cells mediated by HIV-1 gp120 is one of the critical mechanisms leading to T cell loss in AIDS. Clinical studies have shown that T cells in the lymph nodes of HIV-1 infected individuals undergo activation-induced apoptosis. In the present study, we used a model where T cells undergo apoptosis after HIV-1 gp120/CD4 cross-linking in conjunction with CD3/T cell antigen receptor activation. We have shown that treatment with HIV-1 gp120 (10 nM) and anti-gp120 MoAb induces approximately 20–25% apoptosis in Jurkat T cells in the presence of immobilized anti-CD3 antibody. However, the molecular mechanism by which HIV-1 gp120 mediates the apoptosis of T cells is still unclear. We have also examined the role of Akt/Protein kinase B in HIV-1 gp120-induced apoptosis. Akt is a cell survival molecule that has been shown to block cell death. We observed a decrease in Akt phosphorylation upon gp120 treatment of Jurkat T cells and peripheral blood mononuclear cells (PBMCs). In contrast, only CD3 stimulation was shown to increase the phosphorylation of Akt. To further confirm the role of Akt in gp120-induced apoptosis, Jurkat T cells were transfected with HA epitope-tagged wild type Akt, dominant-negative Akt that lacks kinase activity, or with a control vector. The transfected cells were treated with gp120 and apoptosis was evaluated by Annexin-PI staining. The T cells expressing wild type Akt showed reduced gp120 apoptosis as compared to the vector control-expressing cells. Conversely, expression of a dominant-negative mutant of Akt accelerated cell death as compared to the vector control. We then further assessed the role of upstream regulators of Akt, such as PI-3 kinase. In this regard, we have shown that inhibition of PI-3 kinase leads to enhanced gp120-induced apoptosis. At present, we are elucidating downstream effectors of the Akt pathway. Taken together, these studies suggest that Akt plays a key role in HIV-1 gp120-induced apoptosis, and that identification of Akt-mediated signaling pathways may provide novel therapeutic targets to combat immune deficiency in AIDS.
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Mörner, Andreas, Iyadh Douagi, Mattias N. E. Forsell, Christopher Sundling, Pia Dosenovic, Sijy O'Dell, Barna Dey et al. « Human Immunodeficiency Virus Type 1 Env Trimer Immunization of Macaques and Impact of Priming with Viral Vector or Stabilized Core Protein ». Journal of Virology 83, no 2 (12 novembre 2008) : 540–51. http://dx.doi.org/10.1128/jvi.01102-08.
Texte intégralRésumé :
ABSTRACT Currently there is limited information about the quality of immune responses elicited by candidate human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env)-based immunogens in primates. Here we describe a comprehensive analysis of neutralizing antibody and T-cell responses obtained in cynomolgus macaques by three selected immunization regimens. We used the previously described YU2-based gp140 protein trimers administered in an adjuvant, preceded by two distinct priming strategies: either alphavirus replicon particles expressing matched gp140 trimers or gp120 core proteins stabilized in the CD4-bound conformation. The rationale for priming with replicon particles was to evaluate the impact of the expression platform on trimer immunogenicity. The stable core proteins were chosen in an attempt to expand selectively lymphocytes recognizing common determinants between the core and trimers to broaden the immune response. The results presented here demonstrate that the platform by which Env trimers were delivered in the priming (either protein or replicon vector) had little impact on the overall immune response. In contrast, priming with stable core proteins followed by a trimer boost strikingly focused the T-cell response on the core sequences of HIV-1 Env. The specificity of the T-cell response was distinctly different from that of the responses obtained in animals immunized with trimers alone and was shown to be mediated by CD4+ T cells. However, this regimen showed limited or no improvement in the neutralizing antibody responses, suggesting that further immunogen design efforts are required to successfully focus the B-cell response on conserved neutralizing determinants of HIV-1 Env.
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Bruce, Christine B., Alan Akrigg, Sally A. Sharpe, Tomáš Hanke, Gavin W. G. Wilkinson et Martin P. Cranage. « Replication-deficient recombinant adenoviruses expressing the human immunodeficiency virus Env antigen can induce both humoral and CTL immune responses in mice ». Journal of General Virology 80, no 10 (1 octobre 1999) : 2621–28. http://dx.doi.org/10.1099/0022-1317-80-10-2621.
Texte intégralRésumé :
An effective vaccine against infection with human immunodeficiency virus type 1 (HIV-1) is thought likely to require both a humoral and a CTL immune response. A non-replicating adenovirus vector system has been developed that can induce both a humoral and CTL response to HIV-1 envelope in mice. It is demonstrated that the stimulatory tat/rev 5′ splice-donor site sequence is required for efficient expression of HIV-1 env by this adenovirus vector system. rev can be provided bicistronically or in trans to result in good expression of env in vitro. A humoral immune response was detected after two immunizations with a bicistronic recombinant adenovirus (RAd142). The response was dose dependent, 5×107 p.f.u. inducing a response in some, but not all, animals and 1×108 p.f.u. giving a consistent antibody response. However, CTLs were induced by the lower dose of virus and after only one immunization with the higher dose. A positive CTL response was also seen consistently when the two monocistronic adenoviruses (RAd501 expressing env and RAd46 expressing rev) were given together, although two immunizations were required to give approximately the same level of response as seen with the bicistronic virus. RAd501 on its own also gave a low CTL response when two immunizations were given. It is suggested that a lower level of env expression is required to produce a CTL response than a humoral response and that this non- replicating adenovirus vector is a good system for inducing CTL.
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Lemiale, Franck, Mario Pereira, Laurent Humeau et Boro Dropulic. « Transduction and Expansion of HIV+ CD4 T Cells with an HIV-1 Based Lentiviral Vector and Immobilized CD3/CD28 Antibodies Maintains the Diversity of the TCR Vβ Repertoire. » Blood 104, no 11 (16 novembre 2004) : 1759. http://dx.doi.org/10.1182/blood.v104.11.1759.1759.
Texte intégralRésumé :
Abstract Recently, we initiated the first ex vivo HIV-based gene therapy trial in humans with HIV+ CD4+ T cells. In this protocol, a modified lentiviral vector carrying an anti-HIV payload is used to modify CD4+ T cells isolated from HIV-infected patients by apheresis and CD8 negative selection. The T cells are activated in the presence of vector and expanded using immobilized CD3/CD28 antibodies, and then infused back into the patient. T cell receptor (TCR) repertoire analysis has value for safety monitoring of adoptive T cell transfers in the detection of aberrant clonal expansions or deletions. In this study, the TCR Vβ repertoire was assessed using a flow cytometry based assay at various time points in the selection/transduction/expansion process of CD4+ T cells. PBMC isolated from whole blood of HIV+ patients were CD4-selected using a CD8 negative selection, followed by enrichment by CD3 antibody. CD4+ purified cells were transduced with the lentiviral vector, VRX496, in the presence of retronectin, and then co-cultured with CD3/CD28 coated M450 Dynabeads for ten days. The TCR Vβ repertoire was assessed in throughout the process using a FACS-based assay that employs a panel of 20 monoclonal antibodies recognizing most of the 24 Vβ families in PBMC and CD4+ T cells. Repertoires from subjects with normal polyclonal TCR profiles were conserved, as shown by the absence of any significant change in any Vβ family. Moreover, the transduction/expansion of CD4+ T cells from a patient with a previously skewed TCR profile allowed the improvement of the TCR Vβ repertoire. Finally, no significant difference was observed in the repertoire of cells transduced with VRX496 versus mock-transduced cells. These data demonstrate stability of the repertoire diversity and thus provide important support information in favor of the safety of a gene therapy approach involving lentiviral vector mediated modification and expansion of CD4+ T-cells.
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Swan, Christina H., Bernd Buhler, Mario P. Tschan, Carlos F. Barbas et Bruce E. Torbett. « Lentiviral CCR5 Intrabody Gene Delivery Provides Protection and Enrichment during CCR5-Tropic Infection. » Blood 104, no 11 (16 novembre 2004) : 1755. http://dx.doi.org/10.1182/blood.v104.11.1755.1755.
Texte intégralRésumé :
Abstract The molecular mechanism of human immunodeficiency virus type 1 (HIV-1) entry into target cells is a multistep mechanism. The viral envelope glycoproteins (env) binds first to CD4 and subsequently interacts with the V3 loop with a chemokine receptor, CCR5 or CXCR4, triggering the fusion event. Several findings suggest that viruses using CCR5 for entry (R5-tropic HIV-1) is the predominant species transmitted among patients. Importantly, CCR5 expression levels determine disease progression. CCR5 does not seem to be necessary for normal cell function, since individuals with a homozygous mutation (Δ32) do not appear to have clinical, immune alterations. Furthermore, these individuals are highly protected against transmission of R5-tropic HIV-1. Therefore, intervention strategies aimed at altering or blocking CCR5 expression may be beneficial for cellular protection and provide a clinical benefit against HIV-1 infection. We have constructed an HIV-1 derived vector, CAD-R5, expressing an intracellular single-chain antibody (intrabody) specific for CCR5 coupled to a KDEL endoplasmic reticulum retention signal. Intrabody expressing primary T-cells efficiently disrupted CCR5 cell surface expression with a 4.3-fold reduction in CCR5 mean fluorescence intensity (MFI) as compared to the control vector without the intrabody gene (7.9 and 33.6 MFI, respectfully). CAD-R5 transduced primary CD4 T-cells expressing the intrabody gene were resistant to R5-tropic HIV infection as shown by a 50 to 60-fold reduction in HIV-1 p24 concentration. Moreover, intrabody gene expressing cells demonstrated a selective advantage and enriched by 6.4-fold in a population of infected cells as compared to uninfected or infected cells containing vector without the intrabody gene. The SCID-human mouse model, produced by conjoining fetal human thymus and liver under the renal capsule, has become a staple for in vivo testing of T cell anti-retroviral therapy. When CAD-R5 transduced, fetal liver derived CD34+ stem cells were used for reconstitution of the human implants in SCID-hu mice (n = 2, 2 groups), 6-weeks later the human thymi displayed an average of 25% reporter gene expressing T cells. Thymocyte development was not altered by vector integration or loss of CCR5 cell surface expression as determined by the CD4+/CD8+ staining profile. Importantly, CCR5 intrabody expressing thymocytes were also highly resistant to ex vivo R5-tropic HIV-1 challenge with a 3-fold reduction in viral load. These results validate the efficacy of lentiviral delivered CCR5 intrabody mediated protection from R5-tropic HIV-1. The findings also underscore the potential advantage of intrabody gene delivery to CD34+ stem cells, which allows differentiation of protected T cell progeny.
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Jin, Xia, Murugappan Ramanathan,, Shady Barsoum, Geoffrey R. Deschenes, Lei Ba, James Binley, Daryl Schiller et al. « Safety and Immunogenicity of ALVAC vCP1452 and Recombinant gp160 in Newly Human Immunodeficiency Virus Type 1-Infected Patients Treated with Prolonged Highly Active Antiretroviral Therapy ». Journal of Virology 76, no 5 (1 mars 2002) : 2206–16. http://dx.doi.org/10.1128/jvi.76.5.2206-2216.2002.
Texte intégralRésumé :
ABSTRACT In order to boost immune responses in persons in whom highly active antiretroviral therapy (HAART) was initiated within 120 days of the onset of symptoms of newly acquired human immunodeficiency virus type 1 (HIV-1) infection, we administered vaccines containing a canarypox virus vector, vCP1452, with HIV-1 genes encoding multiple HIV-1 proteins, and recombinant gp160. Fifteen HIV-1-infected subjects who achieved sustained suppression of plasma viremia for at least 2 years were enrolled. While continuing antiretroviral therapy, each subject received at least four intramuscular injections of the vaccines on days 0, 30, 90, and 180. Adverse events were mild, with the most common being transient tenderness at the vCP1452 injection site. Of the 14 patients who completed vaccination, 13 had significant increases in anti-gp120 or anti-p24 antibody titers, and 9 had transient augmentation of their T-cell proliferation responses to gp160 and/or p24. HIV-1-specific CD8+ T cells were quantified using an intracellular gamma interferon staining assay. Among 11 patients who had increased CD8+ T-cell responses, seven had responses to more than one HIV-1 antigen. In summary, vaccination with vCP1452 and recombinant gp160 appears safe and immunogenic in newly HIV-1-infected patients on HAART.
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Perreau, Matthieu, Giuseppe Pantaleo et Eric J. Kremer. « Activation of a dendritic cell–T cell axis by Ad5 immune complexes creates an improved environment for replication of HIV in T cells ». Journal of Experimental Medicine 205, no 12 (3 novembre 2008) : 2717–25. http://dx.doi.org/10.1084/jem.20081786.
Texte intégralRésumé :
The STEP HIV vaccine trial, which evaluated a replication-defective adenovirus type 5 (Ad5) vector vaccine, was recently stopped. The reasons for this included lack of efficacy of the vaccine and a twofold increase in the incidence of HIV acquisition among vaccinated recipients with increased Ad5-neutralizing antibody titers compared with placebo recipients. To model the events that might be occurring in vivo, the effect on dendritic cells (DCs) of Ad5 vector alone or treated with neutralizing antiserum (Ad5 immune complexes [IC]) was compared. Ad5 IC induced more notable DC maturation, as indicated by increased CD86 expression, decreased endocytosis, and production of tumor necrosis factor and type I interferons. We found that DC stimulation by Ad5 IC was mediated by the Fcγ receptor IIa and Toll-like receptor 9 interactions. DCs treated with Ad5 IC also induced significantly higher stimulation of Ad5-specific CD8 T cells equipped with cytolytic machinery. In contrast to Ad5 vectors alone, Ad5 IC caused significantly enhanced HIV infection in DC–T cell cocultures. The present results indicate that Ad5 IC activates a DC–T cell axis that, together with the possible persistence of the Ad5 vaccine in seropositive individuals, may set up a permissive environment for HIV-1 infection, which could account for the increased acquisition of HIV-1 infection among Ad5 seropositive vaccine recipients.
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Luckay, Amara, Maninder K. Sidhu, Rune Kjeken, Shakuntala Megati, Siew-Yen Chong, Vidia Roopchand, Dorys Garcia-Hand et al. « Effect of Plasmid DNA Vaccine Design and In Vivo Electroporation on the Resulting Vaccine-Specific Immune Responses in Rhesus Macaques ». Journal of Virology 81, no 10 (28 février 2007) : 5257–69. http://dx.doi.org/10.1128/jvi.00055-07.
Texte intégralRésumé :
ABSTRACT Since human immunodeficiency virus (HIV)-specific cell-mediated immune (CMI) responses are critical in the early control and resolution of HIV infection and correlate with postchallenge outcomes in rhesus macaque challenge experiments, we sought to identify a plasmid DNA (pDNA) vaccine design capable of eliciting robust and balanced CMI responses to multiple HIV type 1 (HIV-1)-derived antigens for further development. Previously, a number of two-, three-, and four-vector pDNA vaccine designs were identified as capable of eliciting HIV-1 antigen-specific CMI responses in mice (M. A. Egan et al., Vaccine 24:4510-4523, 2006). We then sought to further characterize the relative immunogenicities of these two-, three-, and four-vector pDNA vaccine designs in nonhuman primates and to determine the extent to which in vivo electroporation (EP) could improve the resulting immune responses. The results indicated that a two-vector pDNA vaccine design elicited the most robust and balanced CMI response. In addition, vaccination in combination with in vivo EP led to a more rapid onset and enhanced vaccine-specific immune responses. In macaques immunized in combination with in vivo EP, we observed a 10- to 40-fold increase in HIV-specific enzyme-linked immunospot assay responses compared to those for macaques receiving a 5-fold higher dose of vaccine without in vivo EP. This increase in CMI responses translates to an apparent 50- to 200-fold increase in pDNA vaccine potency. Importantly, in vivo EP enhanced the immune response against the less immunogenic antigens, resulting in a more balanced immune response. In addition, in vivo EP resulted in an approximate 2.5-log10 increase in antibody responses. The results further indicated that in vivo EP was associated with a significant reduction in pDNA persistence and did not result in an increase in pDNA associated with high-molecular-weight DNA relative to macaques receiving the pDNA without EP. Collectively, these results have important implications for the design and development of an efficacious vaccine for the prevention of HIV-1 infection.
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Couto, Elvira, Vicenç Diaz-Brito, Beatriz Mothe, Alberto C. Guardo, Irene Fernandez, Ainoa Ugarte, Flor Etcheverry et al. « Comparison of Safety and Vector-Specific Immune Responses in Healthy and HIV-Infected Populations Vaccinated with MVA-B ». Vaccines 7, no 4 (7 novembre 2019) : 178. http://dx.doi.org/10.3390/vaccines7040178.
Texte intégralRésumé :
There are few studies comparing the safety and immunogenicity of the same HIV immunogen in healthy volunteers and HIV-infected individuals. We analyzed demographics, adverse events (AEs), and immunogenicity against vaccinia virus in preventive (RISVAC02, n = 24 low-risk HIV-negative volunteers) and therapeutic (RISVAC03, n = 20 successfully treated chronically HIV-1-infected individuals) vaccine phase-I clinical trials that were performed with the same design and the same immunogen (modified vaccinia virus Ankara-B: MVA-B). Total AEs were significantly higher in HIV-infected patients (mean AEs/patient 6.6 vs. 12.8 (p < 0.01)). Conversely, the number of AEs related to vaccination (AEsRV) was similar between both groups. No grade III or IV AEsRV were observed in either clinical trial. Regarding the immunogenicity, the proportion of anti-vaccinia virus antibody responders was similar in both studies. Conversely, the magnitude of response was significantly higher in HIV-infected patients (median binding antibodies at w8 267 vs. 1600 U/mL (p = 0.002) and at w18 666 vs. 3200 U/mL (p = 0.003)). There was also a trend towards higher anti-vaccinia virus neutralizing activity in HIV-infected individuals (proportion of responders 37% vs. 63% (p = 0.09); median IC50 32 vs. 64 (p = 0.054)). This study confirms the safety of MVA-B independent of HIV serostatus. HIV-infected patients showed higher immune responses against vaccinia virus.
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Laderoute, Marian P. « Clues to finding correlates of risk/protection for HIV-1 vaccines ». F1000Research 6 (12 juin 2017) : 868. http://dx.doi.org/10.12688/f1000research.11818.1.
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Almost a decade later, we still do not understand why in the STEP trial (2008), males with pre-existing antibodies to the Ad5 vector were associated with initial increased risk of HIV-1 acquisition. Similarly, we have little conclusive evidence of why in the RV144 trial (2009), vaccination with the ALVAC-HIV/AIDSVAX B/E was associated initially with almost a 60% vaccine efficacy at year one, which waned over 42 months to 31.2%, and where females were more protected than males. Based on the literature and trial outcomes, it was deduced that the elusive correlate of risk/protection may pertain to a novel, potent, innate protector mechanism launched by alternatively activated macrophages, which is probably induced by viruses and female steroid hormones. It was also suggested this mechanism was not likely amenable to discovery using standard or traditional approaches. A plausible, candidate mechanism was identified with these characteristics, namely the production of human endogenous retrovirus–K102 (HERV-K102) particles, which occurs in, and generates, foamy macrophages in vitro. Accumulating clinical, biological and phylogenetic evidence supports its role in the antagonism of HIV-1 replication and/or in the prevention of HIV-1 acquisition. Thus, it will be important to examine HERV-K102 particle production, increased integration and envelop antibody production as candidate correlates of protection in HIV-1 vaccine trials, as well as in HIV-1 highly exposed seronegative cohorts and elite controllers. The results of such efforts may have important ramifications for the HIV-1 cure in addition to vaccines.
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Kong, Wing-Pui, Yue Huang, Zhi-Yong Yang, Bimal K. Chakrabarti, Zoe Moodie et Gary J. Nabel. « Immunogenicity of Multiple Gene and Clade Human Immunodeficiency Virus Type 1 DNA Vaccines ». Journal of Virology 77, no 23 (1 décembre 2003) : 12764–72. http://dx.doi.org/10.1128/jvi.77.23.12764-12772.2003.
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ABSTRACT The ability to elicit an immune response to a spectrum of human immunodeficiency virus type 1 (HIV-1) gene products from divergent strains is a desirable feature of an AIDS vaccine. In this study, we examined combinations of plasmids expressing multiple HIV-1 genes from different clades for their ability to elicit humoral and cellular immune responses in mice. Immunization with a modified Env, gp145ΔCFI, in combination with a Gag-Pol-Nef fusion protein plasmid elicited similar CD4+ and CD8+ cellular responses to immunization with either vector alone. Further, when mice were immunized with a mixture of Env from three clades, A, B, and C, together with Gag-Pol-Nef, the overall potency and balance of CD4+- and CD8+-T-cell responses to all viral antigens were similar, with only minor differences noted. In addition, plasmid mixtures elicited antibody responses comparable to those from individual inoculations. These findings suggest that a multigene and multiclade vaccine, including components from A, B, and C Env and Gag-Pol-Nef, can broaden antiviral immune responses without immune interference. Such combinations of immunogens may help to address concerns about viral genetic diversity for a prospective HIV-1 vaccine.
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Deml, Ludwig, Alexandra Bojak, Stephanie Steck, Marcus Graf, Jens Wild, Reinhold Schirmbeck, Hans Wolf et Ralf Wagner. « Multiple Effects of Codon Usage Optimization on Expression and Immunogenicity of DNA Candidate Vaccines Encoding the Human Immunodeficiency Virus Type 1 Gag Protein ». Journal of Virology 75, no 22 (15 novembre 2001) : 10991–1001. http://dx.doi.org/10.1128/jvi.75.22.10991-11001.2001.
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ABSTRACT We have analyzed the influence of codon usage modifications on the expression levels and immunogenicity of DNA vaccines, encoding the human immunodeficiency virus type 1 (HIV-1) group-specific antigen (Gag). In the presence of Rev, an expression vector containing the wild-type (wt) gag gene flanked by essentialcis-acting sites such as the 5′-untranslated region and 3′-Rev response element supported substantial Gag protein expression and secretion in human H1299 and monkey COS-7 cells. However, only weak Gag production was observed from the murine muscle cell line C2C12. In contrast, optimization of the Gag coding sequence to that of highly expressed mammalian genes (syngag) resulted in an obvious increase in the G+C content and a Rev-independent expression and secretion of Gag in all tested mammalian cell lines, including murine C2C12 muscle cells. Mice immunized intramuscularly with thesyngag plasmid showed Th1-driven humoral and cellular responses that were substantially higher than those obtained after injection of the Rev-dependent wild-type (wt) gag vector system. In contrast, intradermal immunization of both wtgag and syngag vector systems with the particle gun induced a Th2-biased antibody response and no cytotoxic T lymphocytes. Deletion analysis demonstrated that the CpG motifs generated within syngag by codon optimization do not contribute significantly to the high immunogenicity of thesyngag plasmid. Moreover, low doses of coadministered stimulatory phosphorothioate oligodeoxynucleotides (ODNs) had only a weak effect on antibody production, whereas at higher doses immunostimulatory and nonstimulatory ODNs showed a dose-dependent suppression of humoral responses. These results suggest that increased Gag expression, rather than modulation of CpG-driven vector immunity, is responsible for the enhanced immunogenicity of thesyngag DNA vaccine.
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Zhou, Jingying, Haibo Wang, Zhiwu Tan, Yanhua Du et Zhiwei Chen. « Enhanced HIV-1 Gag-specific immunity induced by a sPD-1-based vaccine directed to dendritic cells (53.23) ». Journal of Immunology 186, no 1_Supplement (1 avril 2011) : 53.23. http://dx.doi.org/10.4049/jimmunol.186.supp.53.23.
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Abstract HIV/AIDS is a serious disease worldwide. The development of a safe, effective and affordable HIV-1 vaccine remains the ultimate solution. This study is based on the discovery of a negative immune regulatory system, the PD-1/PD-L pathway, which exists on both human and other animals. The PD-1 ligands (PD-L1 and PD-L2) are expressed on DCs. So we hypothesize to utilize the soluble PD-1 parts to intervene in the negative signal transmission of the PD-1 pathway and to target the antigen to DCs as a mean to indentify vaccine strategy to enhance the virus specific immune responses. Here we constructed the novel vaccine and controls by inserting soluble PD-1 gene and/or HIV-1 p24 gene into the pVAX1 vector with fusing of rabbit Fc fragment named mspd1-p24-fc, and controls named mspd1-IgVΔ-p24-fc and p24-fc. When compared with control vaccines, we discovered that mspd1-p24fc can significantly enhance HIV-1 Gag-specific immune responses by measuring the number of IFN-γ expressed CD4 and CD8 T cells using Elispot assays and CD8 T cell tetramer staining. Furthermore, the mspd1-p24-fc can significantly enhance humoral immune responses by anti-Gag antibody titer analysis. Importantly, this novel vaccine protects mice against recombinant vaccinia virus-gagpol challenges. This novel vaccine design may be used as DNA vaccine model against other infectious disease and cancer which need eliciting significant antigen specific humoral and cellular immune responses.
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Mangkuliguna, Ghea. « The Potential of eCD4-Ig, Delivered by Adeno-Associated Virus (AAV) Vector as a Novel Vaccine for HIV/AIDS Infection ». SCRIPTA SCORE Scientific Medical Journal 2, no 2 (12 février 2021) : 133–9. http://dx.doi.org/10.32734/scripta.v2i2.3922.
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Background: HIV/AIDS has already become one of the world's major health issues taking its toll on millions of lives each year. Developing an HIV vaccine with excellent efficacy has become a global urgency that must be addressed immediately. Recently, researchers have successfully developed a more self-like molecule which is a fusion protein between human CD4 domains and immunoglobulin G (IgG) Fc with a CCR5-mimetic sulfopeptide in the carboxy terminus. This molecule, eCD4-Ig, targets only the conserved regions of HIV Env and thus demonstrated the most remarkable potency and breadth so far. By using adeno-associated virus (AAV) vector, eCD4-Ig’s long-term expression in vivo can be achieved. Objectives: Evaluate the efficacy of AAV-eCD4-Ig as both preventive and therapeutic vaccine for HIV/AIDS infection. Methods: A systematic literature study was conducted with the database in PubMed, ScienceDirect, and Proquest. No time and language restriction were applied. Discussion: This review shows that eCD4-Ig eliminates HIV-infected cells through neutralization and antibody-dependent cell-mediated cytotoxicity (ADCC). Moreover, eCD4-Ig is also capable of preventing HIV infection in vivo. Delivered with AAV, eCD4-Ig is maintained stably at both protective and therapeutic levels, as well as gives robust protection for rhesus macaques for almost a year long through a single injection. Conclusion: This study offers evidences that AAV-eCD4-Ig appears to have the potential to be an effective vaccine to prevent HIV infection. Keywords: AAV, AIDS, eCD4-Ig, HIV, vaccine Latar Belakang: Pengembangan vaksin HIV yang efektif menjadi sangat penting mengingat tingginya angka kematian yang ditimbulkan oleh HIV/AIDS. Beberapa tahun terakhir, peneliti berhasil menemukan sebuah molekul yang tersusun atas domain CD4 manusia, immunoglobulin G (IgG) Fc, dan sulfopeptida yang menyerupai CCR5. Molekul yang dinamakan eCD4-Ig ini menargetkan area konservatif dari HIV Env sehingga berpotensi untuk menjadi vaksin HIV yang efektif. Ekspresi eCD4-Ig akan dipertahankan menggunakan Adeno-associated Virus Vector (AAV). Tujuan: Evaluasi efektivitas AAV-eCD4-Ig sebagai vaksin untuk HIV/AIDS. Metode: Penelitian dilakukan dengan melakukan tinjauan pustaka dari beberapa database jurnal, yakni PubMed, ScienceDirect, dan Proquest tanpa ada batasan waktu dan bahasa. Pembahasan: eCD4-Ig membunuh sel-sel yang terinfeksi HIV melalui proses netralisasi dan antibody-dependent cell-mediated cytotoxicity (ADCC). eCD4-Ig juga memberikan perlindungan terhadap infeksi HIV. Ekspresi AAV-eCD4-Ig sangat stabil untuk dosis protektif dan terapeutik, sekaligus melindungi rhesus macaques dari infeksi HIV selama hampir 1 tahun lamanya hanya dengan sekali injeksi. Kesimpulan: AAV-eCD4-Ig memiliki potensi yang menjanjikan untuk menjadi vaksin HIV yang efektif bagi seluruh penderita HIV/AIDS di seluruh dunia. Kata Kunci: AAV, AIDS, eCD4-Ig, HIV, vaksin
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Mascarell, Laurent, Catherine Fayolle, Cécile Bauche, Daniel Ladant et Claude Leclerc. « Induction of Neutralizing Antibodies and Th1-Polarized and CD4-Independent CD8+ T-Cell Responses following Delivery of Human Immunodeficiency Virus Type 1 Tat Protein by Recombinant Adenylate Cyclase of Bordetella pertussis ». Journal of Virology 79, no 15 (1 août 2005) : 9872–84. http://dx.doi.org/10.1128/jvi.79.15.9872-9884.2005.
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ABSTRACT HIV-Tat, a conserved protein playing a key role in the early life cycle of the human immunodeficiency virus (HIV) has been proposed as a potential AIDS vaccine. An HIV-Tat-based vaccine should elicit a broad, long-lasting, and neutralizing immune response. We have previously demonstrated that the adenylate cyclase (CyaA) from Bordetella pertussis targets dendritic cells and delivers CD8+ and CD4+ T-cell epitopes into the major histocompatibility complex class I and class II presentation pathways. We have also showed that CyaA induced specific and protective cytotoxic T cell responses in vivo. Here, we designed a prototype vaccine based on the HIV type 1 Tat delivered by CyaA (CyaA-E5-Tat) and tested its capacity to induce HIV-Tat-specific cellular as well as antibody responses. We showed that immunization of mice by CyaA-E5-Tat in the absence of adjuvant elicited strong and long-lasting neutralizing anti-Tat antibody responses more efficient than those obtained after immunization with Tat toxoid in aluminum hydroxide adjuvant. Analyses of the anti-Tat immunoglobulin G isotypes and the cytokine pattern showed that CyaA-E5-Tat induced a Th1-polarized immune response in contrast to the Th2-polarized immune responses obtained with the Tat toxoid. In addition, our data demonstrated that HIV-Tat-specific gamma interferon-producing CD8+ T cells were generated after vaccination with CyaA-E5-Tat in a CD4+ T-cell-independent manner. Based on these findings, CyaA-E5-Tat represents an attractive vaccine candidate for both preventive and therapeutic vaccination involving CyaA as an efficient nonreplicative vector for protein delivery.
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Fischer, Kimberlee M., Margaret L. Just, Carlos F. Barbas et Bruce E. Torbett. « CD34+ Cell Derived Macrophages Are Protected from HIV-1 Challenge by Intrabody-Mediated Reduction of CCR5. » Blood 104, no 11 (16 novembre 2004) : 1756. http://dx.doi.org/10.1182/blood.v104.11.1756.1756.
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Abstract The three main coreceptors that HIV-1 uses for viral entry are CD4 and the chemokine receptors CXCR4 and/or CCR5. Viral tropism dictates which chemokine receptors are used for viral entry. Naturally occurring CCR5 gene polymorphisms resulting in gene deletion (delta 32) results in loss of receptor expression and provides protection from CCR5 using viruses. There are no known deleterious effects of CCR5 loss in mice or in humans. The focus of our studies is to limit infection of myeloid cells by CCR5 using HIV-1s by decreasing CCR5 cell surface expression. We have successfully accomplished this by using HIV-1 vectors to deliver an intrabody directed against CCR5. The CCR5-specific intrabody gene, containing the endoplasmic KDEL sequence, produces a single chain antibody that sequesters CCR5 in the endoplasmic reticulum. We show that >= 93% of THP-1s, a myelomonocytic cell line, transduced with CCR5 intrabody genes stably expressed intrabodies for 6 months. Of cells expressing intrabody, CCR5 was decreased at least 80% on the cell surface. In macrophages derived from CD34+ cells, CCR5 gene expression was maintained at initial transduction levels throughout the 3-week culture period. Colony forming assays (CFU) were performed to assess the effect of intrabody expression on hematopoietic development. No differences were seen in numbers of CFU and colony types when comparing parental, control vector, and intrabody expressing cells (n = 3). To determine the level of protection afforded by CCR5 intrabody expression, macrophages were exposed to JR-FL, a CCR5 using HIV-1, at 0.3 and 0.51 multiplicity of infection. Cultures were maintained for 15 – 23 days and evaluated for p24, a measure of viral replication, at 3 – 8 day intervals. At the end of culture it was found that macrophages expressing CCR5 intrabody generated 42-, 57-, 52-fold less p24 as compared to parental and control vector containing macrophages. Thus, CCR5 intrabody expression drastically decreased viral load. Therefore, reduction of CCR5 through vector delivery of intrabody genes to CD34+ cells should reduce the likelihood of infection of myeloid cells, their function as viral reservoirs, and has promising therapeutic potential. Currently, studies are underway to evaluate this modality of treatment in humanized NOD/SCID mice.
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Chen, Ji-Dai, Qicheng Yang, An-Gang Yang, Wayne A. Marasco et Si-Yi Chen. « Intra- and Extracellular Immunization Against HIV-1 Infection with Lymphocytes Transduced with an AAV Vector Expressing a Human Anti-gp120 Antibody ». Human Gene Therapy 7, no 13 (20 août 1996) : 1515–25. http://dx.doi.org/10.1089/hum.1996.7.13-1515.
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Wen, Jing, Yi Yang, Guangyu Zhao, Shuang Tong, Hong Yu, Xia Jin, Lanying Du, Shibo Jiang, Zhihua Kou et Yusen Zhou. « Salmonella typhi Ty21a bacterial ghost vector augments HIV-1 gp140 DNA vaccine-induced peripheral and mucosal antibody responses via TLR4 pathway ». Vaccine 30, no 39 (août 2012) : 5733–39. http://dx.doi.org/10.1016/j.vaccine.2012.07.008.
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Jahedian, Shekoufa, Seyed Mehdi Sadat, Gholam Reza Javadi et Azam Bolhassani. « Production and Evaluation of the Properties of HIV-1-Nef-MPER-V3 Fusion Protein Harboring IMT-P8 Cell Penetrating Peptide ». Current HIV Research 18, no 5 (16 octobre 2020) : 315–23. http://dx.doi.org/10.2174/1570162x18666200612151925.
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Background: Finding a safe and effective vaccine for HIV-1 infection is still a major concern. Objective: This study aimed to design and produce a recombinant Nef-MPER V3 protein fused with IMT-P8 using E. coli expression system to provide a potential HIV vaccine with high cellular penetrance. Methods: After synthesizing the DNA sequence of the fusion protein, the construct was inserted into the pET-28 expression vector. The recombinant protein expression was induced using 1 mM IPTG and the product was purified through affinity chromatography. Characterization of cellular delivery, toxicity and immunogenicity of the protein was carried out. Results: The recombinant protein was expressed and confirmed by the anti-Nef antibody through western blotting. Data analyses showed that the protein possessed no considerable toxicity effect and has improved the IMT-P8 penetration rate in comparison to a control sample. Moreover, the antigen immunogenicity of the protein induced specific humoral response in mice. Conclusion: It was concluded that IMT-P8-Nef-MPER-V3 fusion protein has a high penetrance rate in mammalian cell line and low toxicity, thus it can be potentially considered as a vaccine against HIV-1.
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Stitz, Jörn, Nina Wolfrum, Christian J. Buchholz et Klaus Cichutek. « Envelope proteins of spleen necrosis virus form infectious human immunodeficiency virus type 1 pseudotype vector particles, but fail to incorporate upon substitution of the cytoplasmic domain with that of Gibbon ape leukemia virus ». Journal of General Virology 87, no 6 (1 juin 2006) : 1577–81. http://dx.doi.org/10.1099/vir.0.81231-0.
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The wild-type (wt) envelope (Env) proteins of spleen necrosis virus (SNV), together with the transmembrane (TM) protein fused to antibody domains (scFv), have been used for the generation of stable packaging cell lines releasing pseudotyped cell targeting vectors derived from SNV and Murine leukemia virus (MLV). As a first step towards assessing whether HIV-1(SNV/TM-scFv) packaging cells could be established for the production of lentiviral cell targeting vectors, it is reported here that infectious HIV-1-derived particles pseudotyped with wt SNV Env proteins could be generated. Using novel chimeric SNV-derived Env proteins encompassing wt and engineered cytoplasmic domains (C-tail) of the Gibbon ape leukemia virus (GaLV) TM protein, it was further shown that the wt C-tail not only excludes the GaLV TM protein from incorporation into HIV-1 particles, but confers this phenotype to other retroviral envelopes upon C-terminal fusion.
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Kilgore, Katie M., Megan K. Murphy, Samantha L. Burton, Katherine S. Wetzel, S. Abigail Smith, Peng Xiao, Sharmila Reddy et al. « Characterization and Implementation of a Diverse Simian Immunodeficiency Virus SIVsm Envelope Panel in the Assessment of Neutralizing Antibody Breadth Elicited in Rhesus Macaques by Multimodal Vaccines Expressing the SIVmac239 Envelope ». Journal of Virology 89, no 16 (27 mai 2015) : 8130–51. http://dx.doi.org/10.1128/jvi.01221-14.
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ABSTRACTAntibodies that can neutralize diverse viral strains are likely to be an important component of a protective human immunodeficiency virus type 1 (HIV-1) vaccine. To this end, preclinical simian immunodeficiency virus (SIV)-based nonhuman primate immunization regimens have been designed to evaluate and enhance antibody-mediated protection. However, these trials often rely on a limited selection of SIV strains with extreme neutralization phenotypes to assess vaccine-elicited antibody activity. To mirror the viral panels used to assess HIV-1 antibody breadth, we created and characterized a novel panel of 14 genetically and phenotypically diverse SIVsm envelope (Env) glycoproteins. To assess the utility of this panel, we characterized the neutralizing activity elicited by four SIVmac239 envelope-expressing DNA/modified vaccinia virus Ankara vector- and protein-based vaccination regimens that included the immunomodulatory adjuvants granulocyte-macrophage colony-stimulating factor, Toll-like receptor (TLR) ligands, and CD40 ligand. The SIVsm Env panel exhibited a spectrum of neutralization sensitivity to SIV-infected plasma pools and monoclonal antibodies, allowing categorization into three tiers. Pooled sera from 91 rhesus macaques immunized in the four trials consistently neutralized only the highly sensitive tier 1a SIVsm Envs, regardless of the immunization regimen. The inability of vaccine-mediated antibodies to neutralize the moderately resistant tier 1b and tier 2 SIVsm Envs defined here suggests that those antibodies were directed toward epitopes that are not accessible on most SIVsm Envs. To achieve a broader and more effective neutralization profile in preclinical vaccine studies that is relevant to known features of HIV-1 neutralization, more emphasis should be placed on optimizing the Env immunogen, as the neutralization profile achieved by the addition of adjuvants does not appear to supersede the neutralizing antibody profile determined by the immunogen.IMPORTANCEMany in the HIV/AIDS vaccine field believe that the ability to elicit broadly neutralizing antibodies capable of blocking genetically diverse HIV-1 variants is a critical component of a protective vaccine. Various SIV-based nonhuman primate vaccine studies have investigated ways to improve antibody-mediated protection against a heterologous SIV challenge, including administering adjuvants that might stimulate a greater neutralization breadth. Using a novel SIV neutralization panel and samples from four rhesus macaque vaccine trials designed for cross comparison, we show that different regimens expressing the same SIV envelope immunogen consistently elicit antibodies that neutralize only the very sensitive tier 1a SIV variants. The results argue that the neutralizing antibody profile elicited by a vaccine is primarily determined by the envelope immunogen and is not substantially broadened by including adjuvants, resulting in the conclusion that the envelope immunogen itself should be the primary consideration in efforts to elicit antibodies with greater neutralization breadth.
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Wright, Edward, Nigel J. Temperton, Denise A. Marston, Lorraine M. McElhinney, Anthony R. Fooks et Robin A. Weiss. « Investigating antibody neutralization of lyssaviruses using lentiviral pseudotypes : a cross-species comparison ». Journal of General Virology 89, no 9 (1 septembre 2008) : 2204–13. http://dx.doi.org/10.1099/vir.0.2008/000349-0.
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Cross-neutralization between rabies virus (RABV) and two European bat lyssaviruses (EBLV-1 and -2) was analysed using lentiviral pseudotypes as antigen vectors. Glycoprotein (G-protein) cDNA from RABV challenge virus standard-11 (CVS-11) and EBLV-1 and -2 were cloned and co-expressed with human immunodeficiency virus (HIV) or murine leukemia virus (MLV) gag–pol and packageable green fluorescent protein (GFP) or luciferase reporter genes in human cells. The harvested lentiviral (HIV) vector infected over 40 % of baby hamster kidney (BHK) target cells, providing high-titre pseudotype stocks. Tests on blinded antibody-positive (n=15) and -negative (n=45) sera, predetermined by the fluorescent antibody virus neutralization (FAVN) test approved by the World Health Organization (WHO) and Office International des Epizooties (OIE), revealed that the CVS-11 pseudotype assay had 100 % concordance with FAVN and strongly correlated with neutralization titres (r 2=0.89). Cross-neutralization tests using sera from RABV-vaccinated humans and animals on pseudotypes with CVS-11, EBLV-1 and EBLV-2 envelopes showed that the relative neutralization titres correlated broadly with the degree of G-protein diversity. Pseudotypes have three major advantages over live-virus neutralization tests: (i) they can be handled in low-biohazard-level laboratories; (ii) the use of reporter genes such as GFP or β-galactosidase will allow the assay to be undertaken at low cost in laboratories worldwide; (iii) each assay requires <10 μl serum. This robust microassay will improve our understanding of the protective humoral immunity that current rabies vaccines confer against emerging lyssaviruses, and will be applicable to surveillance studies, thus helping to control the spread of rabies.
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Publicover, Jean, Elizabeth Ramsburg et John K. Rose. « Characterization of Nonpathogenic, Live, Viral Vaccine Vectors Inducing Potent Cellular Immune Responses ». Journal of Virology 78, no 17 (1 septembre 2004) : 9317–24. http://dx.doi.org/10.1128/jvi.78.17.9317-9324.2004.
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ABSTRACT Experimental vaccines based on recombinant vesicular stomatitis viruses (VSV) expressing foreign viral proteins are protective in several animal disease models. Although these attenuated viruses are nonpathogenic in nonhuman primates when given by nasal, oral, or intramuscular routes, they are pathogenic in mice when given intranasally, and further vector attenuation may be required before human trials with VSV-based vectors can begin. Mutations truncating the VSV glycoprotein (G) cytoplasmic domain from 29 to 9 or 1 amino acid (designated CT9 or CT1, respectively) were shown previously to attenuate VSV growth in cell culture and pathogenesis in mice. Here we show that VSV recombinants carrying either the CT1 or CT9 deletion and expressing the human immunodeficiency virus (HIV) Env protein are nonpathogenic in mice, even when given by the intranasal route. We then carried out a detailed analysis of the CD8+ T-cell responses, including in vivo cytotoxic T-cell activity, induced by these vectors. When given by either the intranasal or intraperitoneal route, the VSV-CT9 vector expressing HIV Env elicited primary and memory CD8+ T-cell responses to Env equivalent to those elicited by recombinant wild-type VSV expressing Env. The VSV-CT1 vector also induced potent CD8+ T-cell responses after intraperitoneal vaccination, but was less effective when given by the intranasal route. The VSV-CT1 vector was also substantially less effective than the VSV-CT9 or wild-type vector at inducing antibody to Env. The VSV-CT9 vector appears ideal because of its lack of pathogenesis, propagation to high titers in vitro, and stimulation of strong cellular and humoral immune responses.
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Iyer, Smita S., Sailaja Gangadhara, Blandine Victor, Xiaoying Shen, Xuemin Chen, Rafiq Nabi, Sudhir P. Kasturi et al. « Virus-Like Particles Displaying Trimeric Simian Immunodeficiency Virus (SIV) Envelope gp160 Enhance the Breadth of DNA/Modified Vaccinia Virus Ankara SIV Vaccine-Induced Antibody Responses in Rhesus Macaques ». Journal of Virology 90, no 19 (27 juillet 2016) : 8842–54. http://dx.doi.org/10.1128/jvi.01163-16.
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ABSTRACTThe encouraging results of the RV144 vaccine trial have spurred interest in poxvirus prime-protein boost human immunodeficiency virus (HIV) vaccine modalities as a strategy to induce protective immunity. Because vaccine-induced protective immunity is critically determined by HIV envelope (Env) conformation, significant efforts are directed toward generating soluble trimeric Env immunogens that assume native structures. Using the simian immunodeficiency virus (SIV)-macaque model, we tested the immunogenicity and efficacy of sequential immunizations with DNA (D), modified vaccinia virus Ankara (MVA) (M), and protein immunogens, all expressing virus-like particles (VLPs) displaying membrane-anchored trimeric Env. A single VLP protein boost displaying trimeric gp160 adjuvanted with nanoparticle-encapsulated Toll-like receptor 4/7/8 (TLR4/7/8) agonists, administered 44 weeks after the second MVA immunization, induced up to a 3-fold increase in Env-specific IgG binding titers in serum and mucosa. Importantly, the VLP protein boost increased binding antibody against scaffolded V1V2, antibody-dependent phagocytic activity against VLP-coated beads, and antibody breadth and neutralizing antibody titers against homologous and heterologous tier 1 SIVs. Following 5 weekly intrarectal SIVmac251 challenges, two of seven DNA/MVA and VLP (DM+VLP)-vaccinated animals were completely protected compared to productive infection in all seven DM-vaccinated animals. Vaccinated animals demonstrated stronger acute viral pulldown than controls, but a trend for higher acute viremia was observed in the DM+VLP group, likely due to a slower recall of Gag-specific CD8 T cells. Our findings support immunization with VLPs containing trimeric Env as a strategy to augment protective antibody but underscore the need for optimal engagement of CD8 T cells to achieve robust early viral control.IMPORTANCEThe development of an effective HIV vaccine remains a global necessity for preventing HIV infection and reducing the burden of AIDS. While this goal represents a formidable challenge, the modest efficacy of the RV144 trial indicates that multicomponent vaccination regimens that elicit both cellular and humoral immune responses can prevent HIV infection in humans. However, whether protein immunizations synergize with DNA prime-viral vector boosts to enhance cellular and humoral immune responses remains poorly understood. We addressed this question in a nonhuman primate model, and our findings show benefit for sequential protein immunization combined with a potent adjuvant in boosting antibody titers induced by a preceding DNA/MVA immunization. This promising strategy can be further developed to enhance neutralizing antibody responses and boost CD8 T cells to provide robust protection and viral control.
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Panas, Michael W., et Norman L. Letvin. « Role for Gr-1+Cells in the Control of High-Dose Mycobacterium bovis Recombinant BCG ». Clinical and Vaccine Immunology 21, no 8 (11 juin 2014) : 1120–27. http://dx.doi.org/10.1128/cvi.00363-14.
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ABSTRACTMycobacterium bovisbacillus Calmette-Guérin (BCG) is an attractive target for development as a live vaccine vector delivering transgenic antigens from HIV and other pathogens. Most studies aimed at defining the clearance of BCG have been performed at doses between 102and 104CFU. Interestingly, however, recombinant BCG (rBCG) administered at doses of >106CFU effectively generates antigen-specific T-cell responses and primes for heterologous boost responses. Thus, defining clearance at high doses might aid in the optimization of rBCG as a vector. In this study, we used bioluminescence imaging to examine the kinetics of rBCG transgene expression and clearance in mice immunized with 5 × 107CFU rBCG expressing luciferase. Similar to studies using low-dose rBCG, our results demonstrate that the adaptive immune response is necessary for long-term control of rBCG beginning 9 days after immunizing mice. However, in contrast to these reports, we observed that the majority of mycobacterial antigen was eliminated prior to day 9. By examining knockout and antibody-mediated depletion mouse models, we demonstrate that the rapid clearance of rBCG occurs in the first 24 h and is mediated by Gr-1+cells. As Gr-1+granulocytes have been described as having no impact on BCG clearance at low doses, our results reveal an unappreciated role for Gr-1+neutrophils and inflammatory monocytes in the clearance of high-dose rBCG. This work demonstrates the potential of applying bioluminescence imaging to rBCG in order to gain an understanding of the immune response and increase the efficacy of rBCG as a vaccine vector.
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Johnston, Margaret I., Patricia E. Fast, Mary Clare Walker et Daniel Hoth. « The Potential of Vaccines for the Control of AIDS ». Canadian Journal of Infectious Diseases 5, suppl a (1994) : 36A—41A. http://dx.doi.org/10.1155/1994/390423.
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The goal of a prophylactic human immunodeficiency (HIV) vaccine is to elicit immune response(s) that will, upon subsequent exposure to HIV. prevent lnfection and/or disease. On the other hand. therapeutic administration of a vaccine to an individual in whom infection is already established might benefit the individual by augmenting existing functional immune responses or inducing new ones. Development of vaccines for the prevention of AIDS offers unique challenges. Concerns regarding the safely of attenuated and whole-killed products have led to the pursuit of alternativc designs. including recombinant proteins, vectors and particles, synthetic peptides and naked DNA. Seven recombinant envelope. two recombinant vector and four other candidate vaccines that have entered into phase 1 trials in noninfected individuals have proven safe to date, and have differed In their ability lo induce functional antibody and Cytotoxic T lymphocytes. Two recombinant envelope products have recently progressed to phase 2 testing, Five envelope-based and six other products have entered trial in HIV-infected and individuals and have appeared to be safe, Evidence of new antibody, increased T cell proliferation and lncreased cytotoxic T lymphocyte activity have been reported. Additional placebo controlled trials will be required to evaluate the impact of therapeutic vaccination on CD4 cell count. viral burdrn and clinical end-points. The status of HIV/AIDS vaccine development is reviewed. with emphasis on the challenging task of finding an effieacious, safe, prophylactic vaccine.
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Perdiguero, Beatriz, Cristina Sánchez-Corzo, Carlos Sorzano, Lidia Saiz, Pilar Mediavilla, Mariano Esteban et Carmen Gómez. « A Novel MVA-Based HIV Vaccine Candidate (MVA-gp145-GPN) Co-Expressing Clade C Membrane-Bound Trimeric gp145 Env and Gag-Induced Virus-Like Particles (VLPs) Triggered Broad and Multifunctional HIV-1-Specific T Cell and Antibody Responses ». Viruses 11, no 2 (16 février 2019) : 160. http://dx.doi.org/10.3390/v11020160.
Texte intégralRésumé :
The development of an effective Human Immunodeficiency Virus (HIV) vaccine that is able to stimulate both the humoral and cellular HIV-1-specific immune responses remains a major priority challenge. In this study, we described the generation and preclinical evaluation of single and double modified vaccinia virus Ankara (MVA)-based candidates expressing the HIV-1 clade C membrane-bound gp145(ZM96) trimeric protein and/or the Gag(ZM96)-Pol-Nef(CN54) (GPN) polyprotein that was processed to form Gag-induced virus-like particles (VLPs). In vitro characterization of MVA recombinants revealed the stable integration of HIV-1 genes without affecting its replication capacity. In cells that were infected with Env-expressing viruses, the gp145 protein was inserted into the plasma membrane exposing critical epitopes that were recognized by broadly neutralizing antibodies (bNAbs), whereas Gag-induced VLPs were released from cells that were infected with GPN-expressing viruses. VLP particles as well as purified MVA virions contain Env and Gag visualized by immunoelectron microscopy and western-blot of fractions that were obtained after detergent treatments of purified virus particles. In BALB/c mice, homologous MVA-gp145-GPN prime/boost regimen induced broad and polyfunctional Env- and Gag-specific CD4 T cells and antigen-specific T follicular helper (Tfh) and Germinal Center (GC) B cells, which correlated with robust HIV-1-specific humoral responses. Overall, these results support the consideration of MVA-gp145-GPN vector as a potential vaccine candidate against HIV-1.