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Harwood OE, Balgeman AJ, Weaver AJ, Ellis-Connell AL, Weiler AM, Erickson KN, Matschke LM, Golfinos AE, Vezys V, Skinner PJ, Safrit JT, Edlefsen PT, Reynolds MR, Friedrich TC, O’Connor SL. Transient T Cell Expansion, Activation, and Proliferation in Therapeutically Vaccinated Simian Immunodeficiency Virus-Positive Macaques Treated with N-803. J Virol 2022; 96:e0142422. [PMID: 36377872 PMCID: PMC9749465 DOI: 10.1128/jvi.01424-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 10/25/2022] [Indexed: 11/16/2022] Open
Abstract
Vaccine strategies aimed at eliciting human immunodeficiency virus (HIV)-specific CD8+ T cells are one major target of interest in HIV functional cure strategies. We hypothesized that CD8+ T cells elicited by therapeutic vaccination during antiretroviral therapy (ART) would be recalled and boosted by treatment with the interleukin 15 (IL-15) superagonist N-803 after ART discontinuation. We intravenously immunized four simian immunodeficiency virus-positive (SIV+) Mauritian cynomolgus macaques receiving ART with vesicular stomatitis virus (VSV), modified vaccinia virus Ankara strain (MVA), and recombinant adenovirus serotype 5 (rAd-5) vectors all expressing SIVmac239 Gag. Immediately after ART cessation, these animals received three doses of N-803. Four control animals received no vaccines or N-803. The vaccine regimen generated a high-magnitude response involving Gag-specific CD8+ T cells that were proliferative and biased toward an effector memory phenotype. We then compared cells elicited by vaccination (Gag specific) to cells elicited by SIV infection and unaffected by vaccination (Nef specific). We found that N-803 treatment enhanced the frequencies of both bulk and proliferating antigen-specific CD8+ T cells elicited by vaccination and the antigen-specific CD8+ T cells elicited by SIV infection. In sum, we demonstrate that a therapeutic heterologous prime-boost-boost (HPBB) vaccine can elicit antigen-specific effector memory CD8+ T cells that are boosted by N-803. IMPORTANCE While antiretroviral therapy (ART) can suppress HIV replication, it is not a cure. It is therefore essential to develop therapeutic strategies to enhance the immune system to better become activated and recognize virus-infected cells. Here, we evaluated a novel therapeutic vaccination strategy delivered to SIV+ Mauritian cynomolgus macaques receiving ART. ART was then discontinued and we delivered an immunotherapeutic agent (N-803) after ART withdrawal with the goal of eliciting and boosting anti-SIV cellular immunity. Immunologic and virologic analysis of peripheral blood and lymph nodes collected from these animals revealed transient boosts in the frequency, activation, proliferation, and memory phenotype of CD4+ and CD8+ T cells following each intervention. Overall, these results are important in educating the field of the transient nature of the immunological responses to this particular therapeutic regimen and the similar effects of N-803 on boosting T cells elicited by vaccination or elicited naturally by infection.
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Affiliation(s)
- Olivia E. Harwood
- Department of Pathology and Laboratory Medicine, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Alexis J. Balgeman
- Department of Pathology and Laboratory Medicine, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Abigail J. Weaver
- Department of Pathology and Laboratory Medicine, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Amy L. Ellis-Connell
- Department of Pathology and Laboratory Medicine, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Andrea M. Weiler
- Wisconsin National Primate Research Center, Madison, Wisconsin, USA
| | | | - Lea M. Matschke
- Department of Pathobiological Sciences, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Athena E. Golfinos
- Department of Pathology and Laboratory Medicine, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Vaiva Vezys
- Center for Immunology, Department of Microbiology and Immunology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Pamela J. Skinner
- Department of Veterinary and Biomedical Sciences, University of Minnesota, Minneapolis, Minnesota, USA
| | | | - Paul T. Edlefsen
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, Seattle, Washington, USA
| | - Matthew R. Reynolds
- Department of Pathobiological Sciences, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Thomas C. Friedrich
- Wisconsin National Primate Research Center, Madison, Wisconsin, USA
- Department of Pathobiological Sciences, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Shelby L. O’Connor
- Department of Pathology and Laboratory Medicine, University of Wisconsin—Madison, Madison, Wisconsin, USA
- Wisconsin National Primate Research Center, Madison, Wisconsin, USA
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Virnik K, Rosati M, Medvedev A, Scanlan A, Walsh G, Dayton F, Broderick KE, Lewis M, Bryson Y, Lifson JD, Ruprecht RM, Felber BK, Berkower I. Immunotherapy with DNA vaccine and live attenuated rubella/SIV gag vectors plus early ART can prevent SIVmac251 viral rebound in acutely infected rhesus macaques. PLoS One 2020; 15:e0228163. [PMID: 32130229 PMCID: PMC7055890 DOI: 10.1371/journal.pone.0228163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 01/08/2020] [Indexed: 01/29/2023] Open
Abstract
Anti-retroviral therapy (ART) has been highly successful in controlling HIV replication, reducing viral burden, and preventing both progression to AIDS and viral transmission. Yet, ART alone cannot cure the infection. Even after years of successful therapy, ART withdrawal leads inevitably to viral rebound within a few weeks or months. Our hypothesis: effective therapy must control both the replicating virus pool and the reactivatable latent viral reservoir. To do this, we have combined ART and immunotherapy to attack both viral pools simultaneously. The vaccine regimen consisted of DNA vaccine expressing SIV Gag, followed by a boost with live attenuated rubella/gag vectors. The vectors grow well in rhesus macaques, and they are potent immunogens when used in a prime and boost strategy. We infected rhesus macaques by high dose mucosal challenge with virulent SIVmac251 and waited three days to allow viral dissemination and establishment of a reactivatable viral reservoir before starting ART. While on ART, the control group received control DNA and empty rubella vaccine, while the immunotherapy group received DNA/gag prime, followed by boosts with rubella vectors expressing SIV gag over 27 weeks. Both groups had a vaccine "take" to rubella, and the vaccine group developed antibodies and T cells specific for Gag. Five weeks after the last immunization, we stopped ART and monitored virus rebound. All four control animals eventually had a viral rebound, and two were euthanized for AIDS. One control macaque did not rebound until 2 years after ART release. In contrast, there was only one viral rebound in the vaccine group. Three out of four vaccinees had no viral rebound, even after CD8 depletion, and they remain in drug-free viral remission more than 2.5 years later. The strategy of early ART combined with immunotherapy can produce a sustained SIV remission in macaques and may be relevant for immunotherapy of HIV in humans.
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Affiliation(s)
- Konstantin Virnik
- Laboratory of Immunoregulation, Division of Viral Products, Office of Vaccines, Center for Biologics, Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Margherita Rosati
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland, United States of America
| | - Alexei Medvedev
- Laboratory of Immunoregulation, Division of Viral Products, Office of Vaccines, Center for Biologics, Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Aaron Scanlan
- Laboratory of Immunoregulation, Division of Viral Products, Office of Vaccines, Center for Biologics, Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Gabrielle Walsh
- Laboratory of Immunoregulation, Division of Viral Products, Office of Vaccines, Center for Biologics, Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Frances Dayton
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland, United States of America
| | - Kate E. Broderick
- Inovio Pharmaceuticals, Inc., Plymouth Meeting, Pennsylvania, United States of America
| | - Mark Lewis
- BioQual, Inc., Rockville, Maryland, United States of America
| | - Yvonne Bryson
- Department of Pediatrics, Division of Infectious Disease, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Jeffrey D. Lifson
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Ruth M. Ruprecht
- University of Louisiana at Lafayette, New Iberia Research Center, New Iberia, Louisiana, United States of America
| | - Barbara K. Felber
- Human Retrovirus Pathogenesis Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland, United States of America
| | - Ira Berkower
- Laboratory of Immunoregulation, Division of Viral Products, Office of Vaccines, Center for Biologics, Food and Drug Administration, Silver Spring, Maryland, United States of America
- * E-mail:
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Monette A, Mouland AJ. T Lymphocytes as Measurable Targets of Protection and Vaccination Against Viral Disorders. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2019; 342:175-263. [PMID: 30635091 PMCID: PMC7104940 DOI: 10.1016/bs.ircmb.2018.07.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Continuous epidemiological surveillance of existing and emerging viruses and their associated disorders is gaining importance in light of their abilities to cause unpredictable outbreaks as a result of increased travel and vaccination choices by steadily growing and aging populations. Close surveillance of outbreaks and herd immunity are also at the forefront, even in industrialized countries, where previously eradicated viruses are now at risk of re-emergence due to instances of strain recombination, contractions in viral vector geographies, and from their potential use as agents of bioterrorism. There is a great need for the rational design of current and future vaccines targeting viruses, with a strong focus on vaccine targeting of adaptive immune effector memory T cells as the gold standard of immunity conferring long-lived protection against a wide variety of pathogens and malignancies. Here, we review viruses that have historically caused large outbreaks and severe lethal disorders, including respiratory, gastric, skin, hepatic, neurologic, and hemorrhagic fevers. To observe trends in vaccinology against these viral disorders, we describe viral genetic, replication, transmission, and tropism, host-immune evasion strategies, and the epidemiology and health risks of their associated syndromes. We focus on immunity generated against both natural infection and vaccination, where a steady shift in conferred vaccination immunogenicity is observed from quantifying activated and proliferating, long-lived effector memory T cell subsets, as the prominent biomarkers of long-term immunity against viruses and their associated disorders causing high morbidity and mortality rates.
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Virnik K, Nesti E, Dail C, Scanlan A, Medvedev A, Vassell R, McGuire AT, Stamatatos L, Berkower I. Live rubella vectors can express native HIV envelope glycoproteins targeted by broadly neutralizing antibodies and prime the immune response to an envelope protein boost. Vaccine 2018; 36:5166-5172. [PMID: 30037665 DOI: 10.1016/j.vaccine.2018.07.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 07/03/2018] [Accepted: 07/05/2018] [Indexed: 12/18/2022]
Abstract
Following HIV infection, most people make antibodies to gp120 and gp41, yet only a few make broadly neutralizing antibodies that target key antigenic sites on the envelope glycoproteins. The induction of broadly neutralizing antibodies by immunization remains a major challenge of HIV vaccine research. Difficulties include: variable protein sequence, epitopes that depend on the native conformation, glycosylation that conceals key antigenic determinants, and the assembly of Env trimers that mimic viral spikes. In addition, more potent immunogens may be needed to initiate the response of germline antibody precursors and drive B cell maturation toward antibodies with broad neutralizing activity. We have expressed HIV Env glycoproteins by incorporation into live attenuated rubella viral vectors. The rubella vaccine strain RA27/3 has demonstrated its safety and potency in millions of children. As a vector, it has elicited potent and durable immune responses in macaques to SIV Gag vaccine inserts. We now find that rubella/env vectors can stably express Env core derived glycoproteins ranging in size up to 363 amino acids from HIV clade C strain 426c. The expressed Env glycoproteins bind broadly neutralizing antibodies that target the native CD4 binding site. The vectors grew well in rhesus macaques, and they elicited a vaccine "take" in all animals, as measured by anti-rubella antibodies. By themselves, the vectors elicited modest antibody titers to the Env insert. But the combination of rubella/env prime followed by a homologous protein boost gave a strong response. Neutralizing antibodies appeared gradually after multiple vaccine doses. The vectors will be useful for testing new vaccine inserts and immunization strategies under optimized conditions of vector growth and protein expression.
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Affiliation(s)
- Konstantin Virnik
- Lab of Immunoregulation, DVP, Office of Vaccines, Center for Biologics, FDA, Bldg 72, Room 1212, White Oak Campus, 10903 New Hampshire Ave., Silver Spring, MD 20993, USA
| | - Edmund Nesti
- Lab of Immunoregulation, DVP, Office of Vaccines, Center for Biologics, FDA, Bldg 72, Room 1212, White Oak Campus, 10903 New Hampshire Ave., Silver Spring, MD 20993, USA
| | - Cody Dail
- Lab of Immunoregulation, DVP, Office of Vaccines, Center for Biologics, FDA, Bldg 72, Room 1212, White Oak Campus, 10903 New Hampshire Ave., Silver Spring, MD 20993, USA
| | - Aaron Scanlan
- Lab of Immunoregulation, DVP, Office of Vaccines, Center for Biologics, FDA, Bldg 72, Room 1212, White Oak Campus, 10903 New Hampshire Ave., Silver Spring, MD 20993, USA
| | - Alexei Medvedev
- Lab of Immunoregulation, DVP, Office of Vaccines, Center for Biologics, FDA, Bldg 72, Room 1212, White Oak Campus, 10903 New Hampshire Ave., Silver Spring, MD 20993, USA
| | - Russell Vassell
- Lab of Immunoregulation, DVP, Office of Vaccines, Center for Biologics, FDA, Bldg 72, Room 1212, White Oak Campus, 10903 New Hampshire Ave., Silver Spring, MD 20993, USA
| | - Andrew T McGuire
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Department of Global Health, University of Washington, Seattle, WA, USA
| | - Leonidas Stamatatos
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Department of Global Health, University of Washington, Seattle, WA, USA
| | - Ira Berkower
- Lab of Immunoregulation, DVP, Office of Vaccines, Center for Biologics, FDA, Bldg 72, Room 1212, White Oak Campus, 10903 New Hampshire Ave., Silver Spring, MD 20993, USA.
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5
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Virnik K, Nesti E, Dail C, Hockenbury M, Ni Y, Felber BK, Schief WR, Berkower I. Expression of complete SIV p27 Gag and HIV gp120 engineered outer domains targeted by broadly neutralizing antibodies in live rubella vectors. Vaccine 2017; 35:3272-3278. [PMID: 28483193 DOI: 10.1016/j.vaccine.2017.04.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 04/14/2017] [Accepted: 04/15/2017] [Indexed: 12/30/2022]
Abstract
Infection with HIV or SIV often elicits a potent immune response to viral antigens. This includes T cells and antibodies specific for Gag and Env antigens. In contrast, when given as a vaccine, the same antigens have been weak immunogens, unable to elicit antibodies with comparable titer, durability, or neutralizing activity. We have used the live attenuated rubella vaccine strain RA27/3 as a viral vector to express HIV and SIV antigens. By mimicking an HIV infection, these vectors could elicit stronger and more durable immunity to HIV antigens. The vectors are based on the licensed rubella vaccine strain, which has demonstrated safety and potency in millions of children. One or two doses protect for life against rubella infection. The question was whether rubella vectors could similarly enhance the immunogenicity of a foreign vaccine insert. We have previously reported that rubella vectors can express small protein antigens in vitro and in vivo, where they elicit a strong immune response to the vaccine insert. The vectors have now expressed larger vaccine inserts that include epitope-rich fragments of the Gag matrix and capsid proteins (aa 41-211) or the complete p27 capsid protein with p2 (aa 136-381). These vectors have elicited a robust and durable immune response to Gag in rhesus macaques. This size range also encompasses the engineered outer domain (eOD) of HIV envelope gp120 (172 amino acids). The rubella/eOD-GT6 and GT8 vectors stably expressed glycoproteins that bind germline precursors and mature forms of VRC01-class broadly neutralizing antibodies. These vectors potentially could be used as part of a sequential immunization strategy to initiate the production of broadly neutralizing antibodies.
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Affiliation(s)
- Konstantin Virnik
- Lab of Immunoregulation, DVP, Office of Vaccines, Center for Biologics, FDA, Bldg 72, Room 1212, White Oak Campus, 10903 New Hampshire Ave., Silver Spring, MD 20993, USA
| | - Edmund Nesti
- Lab of Immunoregulation, DVP, Office of Vaccines, Center for Biologics, FDA, Bldg 72, Room 1212, White Oak Campus, 10903 New Hampshire Ave., Silver Spring, MD 20993, USA
| | - Cody Dail
- Lab of Immunoregulation, DVP, Office of Vaccines, Center for Biologics, FDA, Bldg 72, Room 1212, White Oak Campus, 10903 New Hampshire Ave., Silver Spring, MD 20993, USA
| | - Max Hockenbury
- Lab of Immunoregulation, DVP, Office of Vaccines, Center for Biologics, FDA, Bldg 72, Room 1212, White Oak Campus, 10903 New Hampshire Ave., Silver Spring, MD 20993, USA
| | - Yisheng Ni
- Lab of Immunoregulation, DVP, Office of Vaccines, Center for Biologics, FDA, Bldg 72, Room 1212, White Oak Campus, 10903 New Hampshire Ave., Silver Spring, MD 20993, USA
| | - Barbara K Felber
- Human Retrovirus Pathogenesis Section, NCI Frederick, Bldg 535, Room 209, Frederick, MD 21702, USA
| | - William R Schief
- Department of Immunology and Microbial Science, IAVI Neutralizing Antibody Center and Center for HIV/AIDS Vaccine Immunology and Immunogen Discovery, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ira Berkower
- Lab of Immunoregulation, DVP, Office of Vaccines, Center for Biologics, FDA, Bldg 72, Room 1212, White Oak Campus, 10903 New Hampshire Ave., Silver Spring, MD 20993, USA.
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6
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Hu X, Valentin A, Dayton F, Kulkarni V, Alicea C, Rosati M, Chowdhury B, Gautam R, Broderick KE, Sardesai NY, Martin MA, Mullins JI, Pavlakis GN, Felber BK. DNA Prime-Boost Vaccine Regimen To Increase Breadth, Magnitude, and Cytotoxicity of the Cellular Immune Responses to Subdominant Gag Epitopes of Simian Immunodeficiency Virus and HIV. THE JOURNAL OF IMMUNOLOGY 2016; 197:3999-4013. [PMID: 27733554 DOI: 10.4049/jimmunol.1600697] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 09/12/2016] [Indexed: 12/23/2022]
Abstract
HIV sequence diversity and the propensity of eliciting immunodominant responses targeting variable regions of the HIV proteome are hurdles in the development of an effective AIDS vaccine. An HIV-derived conserved element (CE) p24gag plasmid DNA (pDNA) vaccine is able to redirect immunodominant responses to otherwise subdominant and often more vulnerable viral targets. By homology to the HIV immunogen, seven CE were identified in SIV p27Gag Analysis of 31 rhesus macaques vaccinated with full-length SIV gag pDNA showed inefficient induction (58% response rate) of cellular responses targeting these CE. In contrast, all 14 macaques immunized with SIV p27CE pDNA developed robust T cell responses recognizing CE. Vaccination with p27CE pDNA was also critical for the efficient induction and increased the frequency of Ag-specific T cells with cytotoxic potential (granzyme B+ CD107a+) targeting subdominant CE epitopes, compared with the responses elicited by the p57gag pDNA vaccine. Following p27CE pDNA priming, two booster regimens, gag pDNA or codelivery of p27CE+gag pDNA, significantly increased the levels of CE-specific T cells. However, the CE+gag pDNA booster vaccination elicited significantly broader CE epitope recognition, and thus, a more profound alteration of the immunodominance hierarchy. Vaccination with HIV molecules showed that CE+gag pDNA booster regimen further expanded the breadth of HIV CE responses. Hence, SIV/HIV vaccine regimens comprising CE pDNA prime and CE+gag pDNA booster vaccination significantly increased cytotoxic T cell responses to subdominant highly conserved Gag epitopes and maximized response breadth.
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Affiliation(s)
- Xintao Hu
- Human Retrovirus Pathogenesis Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702
| | - Antonio Valentin
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702
| | - Frances Dayton
- Human Retrovirus Pathogenesis Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702
| | - Viraj Kulkarni
- Human Retrovirus Pathogenesis Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702
| | - Candido Alicea
- Human Retrovirus Pathogenesis Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702
| | - Margherita Rosati
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702
| | - Bhabadeb Chowdhury
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702
| | - Rajeev Gautam
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | | | | | - Malcolm A Martin
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
| | - James I Mullins
- Department of Microbiology, University of Washington, Seattle, WA 98195.,Department of Medicine, University of Washington, Seattle, WA 98195.,Department of Global Health, University of Washington, Seattle, WA 98195; and.,Department of Laboratory Medicine, University of Washington, Seattle, WA 98195
| | - George N Pavlakis
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702;
| | - Barbara K Felber
- Human Retrovirus Pathogenesis Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702;
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7
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Musich T, Robert-Guroff M. New developments in an old strategy: heterologous vector primes and envelope protein boosts in HIV vaccine design. Expert Rev Vaccines 2016; 15:1015-27. [PMID: 26910195 DOI: 10.1586/14760584.2016.1158108] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Prime/boost vaccination strategies for HIV/SIV vaccine development have been used since the early 1990s and have become an established method for eliciting cell and antibody mediated immunity. Here we focus on induction of protective antibodies, both broadly neutralizing and non-neutralizing, with the viral envelope being the key target antigen. Prime/boost approaches are complicated by the diversity of autologous and heterologous priming vectors, and by various forms of envelope booster immunogens, many still in development as structural studies aim to design stable constructs with exposure of critical epitopes for protective antibody elicitation. This review discusses individual vaccine components, reviews recent prime/boost strategies and their outcomes, and highlights complicating factors arising as greater knowledge concerning induction of adaptive, protective immunity is acquired.
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Affiliation(s)
- Thomas Musich
- a Vaccine Branch, Center for Cancer Research, National Cancer Institute , National Institutes of Health , Bethesda , MD , USA
| | - Marjorie Robert-Guroff
- a Vaccine Branch, Center for Cancer Research, National Cancer Institute , National Institutes of Health , Bethesda , MD , USA
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