Potential To Streamline Heterologous DNA Prime and NYVAC/Protein Boost HIV Vaccine Regimens in Rhesus Macaques by Employing Improved Antigens.
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UNLABELLED: In a follow-up to the modest efficacy observed in the RV144 trial, researchers in the HIV vaccine field seek to substantiate and extend the results by evaluating other poxvirus vectors and combinations with DNA and protein vaccines. Earlier clinical trials (EuroVacc trials 01 to 03) evaluated the immunogenicity of HIV-1 clade C GagPolNef and gp120 antigens delivered via the poxviral vector NYVAC. These showed that a vaccination regimen including DNA-C priming prior to a NYVAC-C boost considerably enhanced vaccine-elicited immune responses compared to those with NYVAC-C alone. Moreover, responses were improved by using three as opposed to two DNA-C primes. In the present study, we assessed in nonhuman primates whether such vaccination regimens can be streamlined further by using fewer and accelerated immunizations and employing a novel generation of improved DNA-C and NYVAC-C vaccine candidates designed for higher expression levels and more balanced immune responses. Three different DNA-C prime/NYVAC-C+ protein boost vaccination regimens were tested in rhesus macaques. All regimens elicited vigorous and well-balanced CD8(+)and CD4(+)T cell responses that were broad and polyfunctional. Very high IgG binding titers, substantial antibody-dependent cellular cytotoxicity (ADCC), and modest antibody-dependent cell-mediated virus inhibition (ADCVI), but very low neutralization activity, were measured after the final immunizations. Overall, immune responses elicited in all three groups were very similar and of greater magnitude, breadth, and quality than those of earlier EuroVacc vaccines. In conclusion, these findings indicate that vaccination schemes can be simplified by using improved antigens and regimens. This may offer a more practical and affordable means to elicit potentially protective immune responses upon vaccination, especially in resource-constrained settings. IMPORTANCE: Within the EuroVacc clinical trials, we previously assessed the immunogenicity of HIV clade C antigens delivered in a DNA prime/NYVAC boost regimen. The trials showed that the DNA prime crucially improved the responses, and three DNA primes with a NYVAC boost appeared to be optimal. Nevertheless, T cell responses were primarily directed toward Env, and humoral responses were modest. The aim of this study was to assess improved antigens for the capacity to elicit more potent and balanced responses in rhesus macaques, even with various simpler immunization regimens. Our results showed that the novel antigens in fact elicited larger numbers of T cells with a polyfunctional profile and a good Env-GagPolNef balance, as well as high-titer and Fc-functional antibody responses. Finally, comparison of the different schedules indicates that a simpler regimen of only two DNA primes and one NYVAC boost in combination with protein may be very efficient, thus showing that the novel antigens allow for easier immunization protocols.
Published Version (Please cite this version)
Asbach, Benedikt, Alexander Kliche, Josef Köstler, Beatriz Perdiguero, Mariano Esteban, Bertram L Jacobs, David C Montefiori, Celia C LaBranche, et al. (2016). Potential To Streamline Heterologous DNA Prime and NYVAC/Protein Boost HIV Vaccine Regimens in Rhesus Macaques by Employing Improved Antigens. J Virol, 90(8). pp. 4133–4149. 10.1128/JVI.03135-15 Retrieved from https://hdl.handle.net/10161/11663.
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Dr. Montefiori is Professor and Director of the Laboratory for HIV and COVID-19 Vaccine Research & Development in the Department of Surgery, Division of Surgical Sciences at Duke University Medical Center. His major research interests are viral immunology and HIV and COVID-19 vaccine development, with a special emphasis on neutralizing antibodies.
Multiple aspects of HIV-1 neutralizing antibodies are studied in his laboratory, including mechanisms of neutralization and escape, epitope diversity among the different genetic subtypes and geographic distributions of the virus, neutralizing epitopes, requirements to elicit protective neutralizing antibodies by vaccination, optimal combinations of neutralizing antibodies for immunoprophylaxis, and novel vaccine designs for HIV-1. Dr. Montefiori also directs large vaccine immune monitoring programs funded by the NIH and the Bill & Melinda Gates Foundation that operate in compliance with Good Clinical Laboratory Practices and has served as a national and international resource for standardized assessments of neutralizing antibody responses in preclinical and clinical trials of candidate HIV vaccines since 1988.
At the onset of the COVID-19 pandemic he turned his attention to SARS-CoV-2, with a special interest in emerging variants and how they might impact transmission, vaccines and immunotherapeutics. His rapid response to emerging SARS-CoV-2 variants of concern provided some of the earliest evidence of the potential risk the variants pose to vaccines. In May 2020, his laboratory was recruited by the US Government to lead the national neutralizing antibody laboratory program for COVID-19 vaccines.
His laboratory utilizes FDA approved validated assay criteria to facilitate regulatory approvals of COVID-19 vaccines. He has published over 750 original research papers that have helped shape the scientific rationale for antibody-based vaccines.
Dr. Georgia Tomaras is a tenured Professor of Surgery, Professor of Immunology, Professor of Molecular Genetics and Microbiology and is a Fellow of the American Academy of Microbiology (AAM) and a Fellow of the American Association for the Advancement of Science (AAAS). Dr. Tomaras is Co-Director of the Center for Human Systems Immunology (CHSI) Duke University and Director of the Duke Center for AIDS Research (CFAR). Her national and international leadership roles include: Executive Management Team (EMT) leader and mPI for the HIV Vaccine Trials Network (HVTN); Director of Lab Sciences (HVTN); and Chair of NIH Vaccine Research Center (VRC) Board of Scientific Counselors. Her prior leadership roles include serving as the Director of Research, Duke Human Vaccine Institute (DHVI); Director of the DHVI Training Program; Associate Director of DHVI Research; Co-Director of the Interdisciplinary Research Training Program in AIDS (IRTPA) Duke; Chair of the National Institutes of Health (NIH) AIDS Vaccine Research Subcommittee (AVRS), and Advisory Counsel member of the National Institutes of Health (NIH) National Institute of Allergy and Infectious Diseases (NIAID). Dr. Tomaras’ primary research focus is deciphering mechanisms of protective human immunity and identification of immune correlates of protection to further development of effective vaccines against infectious diseases.
The activities of the Ferrari Laboratory are based on both independent basic research and immune monitoring studies. The research revolves around three main areas of interest: class I-mediated cytotoxic CD8+ T cell responses, antibody-dependent cellular cytotoxicity (ADCC), gene expression in NK and T cellular subsets upon infection with HIV-1. With continuous funding over the last 11 years from the NIH and Bill & Melinda Gates Foundation along with many other productive collaborations within and outside of Duke, the Ferrari Lab has expanded its focus of research to include the ontogeny of HIV-1 specific immune responses that work by eliminating HIV-1 infected cells and how these can be induced by AIDS vaccine candidates.
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