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Fonseca JA, King AC, Chahroudi A. More than the Infinite Monkey Theorem: NHP Models in the Development of a Pediatric HIV Cure. Curr HIV/AIDS Rep 2024; 21:11-29. [PMID: 38227162 PMCID: PMC10859349 DOI: 10.1007/s11904-023-00686-6] [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] [Accepted: 12/29/2023] [Indexed: 01/17/2024]
Abstract
PURPOSE OF REVIEW An HIV cure that eliminates the viral reservoir or provides viral control without antiretroviral therapy (ART) is an urgent need in children as they face unique challenges, including lifelong ART adherence and the deleterious effects of chronic immune activation. This review highlights the importance of nonhuman primate (NHP) models in developing an HIV cure for children as these models recapitulate the viral pathogenesis and persistence. RECENT FINDINGS Several cure approaches have been explored in infant NHPs, although knowledge gaps remain. Broadly neutralizing antibodies (bNAbs) show promise for controlling viremia and delaying viral rebound after ART interruption but face administration challenges. Adeno-associated virus (AAV) vectors hold the potential for sustained bNAb expression. Therapeutic vaccination induces immune responses against simian retroviruses but has yet to impact the viral reservoir. Combining immunotherapies with latency reversal agents (LRAs) that enhance viral antigen expression should be explored. Current and future cure approaches will require adaptation for the pediatric immune system and unique features of virus persistence, for which NHP models are fundamental to assess their efficacy.
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Affiliation(s)
- Jairo A Fonseca
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Alexis C King
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
| | - Ann Chahroudi
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA.
- Emory National Primate Research Center, Emory University, Atlanta, GA, USA.
- Emory+Children's Center for Childhood Infections and Vaccines, Atlanta, GA, USA.
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Muenchhoff M, Prendergast AJ, Goulder PJR. Immunity to HIV in Early Life. Front Immunol 2014; 5:391. [PMID: 25161656 PMCID: PMC4130105 DOI: 10.3389/fimmu.2014.00391] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 07/30/2014] [Indexed: 01/14/2023] Open
Abstract
The developing immune system is adapted to the exposure to a plethora of pathogenic and non-pathogenic antigens encountered in utero and after birth, requiring a fine balance between protective immunity and immune tolerance. In early stages of life, this tolerogenic state of the innate and adaptive immune system and the lack of immunological memory render the host more susceptible to infectious pathogens like HIV. HIV pathogenesis is different in children, compared to adults, with more rapid disease progression and a substantial lack of control of viremia compared to adults. Plasma viral load remains high during infancy and only declines gradually over several years in line with immune maturation, even in rare cases where children maintain normal CD4 T-lymphocyte counts for several years without antiretroviral therapy (ART). These pediatric slow progressors also typically show low levels of immune activation despite persistently high viremia, resembling the phenotype of natural hosts of SIV infection. The lack of immunological memory places the fetus and the newborn at higher risk of infections; however, it may also provide an opportunity for unique interventions. Frequencies of central memory CD4+ T-lymphocytes, one of the main cellular reservoirs of HIV, are very low in the newborn child, so immediate ART could prevent the establishment of persistent viral reservoirs and result in "functional cure." However, as recently demonstrated in the case report of the "Mississippi child" who experienced viral rebound after more than 2 years off ART, additional immunomodulatory strategies might be required for sustained viral suppression after ART cessation. In this review, we discuss the interactions between HIV and the developing immune system in children and the potential implications for therapeutic and prophylactic interventions.
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Affiliation(s)
- Maximilian Muenchhoff
- Department of Paediatrics, University of Oxford, Peter Medawar Building for Pathogen Research , Oxford , UK
| | - Andrew J Prendergast
- Centre for Paediatrics, Blizard Institute, Queen Mary University of London , London , UK ; Zvitambo Institute for Maternal and Child Health Research , Harare , Zimbabwe
| | - Philip Jeremy Renshaw Goulder
- Department of Paediatrics, University of Oxford, Peter Medawar Building for Pathogen Research , Oxford , UK ; HIV Pathogenesis Programme, Doris Duke Medical Research Institute, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal , Durban , South Africa
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Goepfert PA, Elizaga ML, Seaton K, Tomaras GD, Montefiori DC, Sato A, Hural J, DeRosa SC, Kalams SA, McElrath MJ, Keefer MC, Baden LR, Lama JR, Sanchez J, Mulligan MJ, Buchbinder SP, Hammer SM, Koblin BA, Pensiero M, Butler C, Moss B, Robinson HL. Specificity and 6-month durability of immune responses induced by DNA and recombinant modified vaccinia Ankara vaccines expressing HIV-1 virus-like particles. J Infect Dis 2014; 210:99-110. [PMID: 24403557 DOI: 10.1093/infdis/jiu003] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Clade B DNA and recombinant modified vaccinia Ankara (MVA) vaccines producing virus-like particles displaying trimeric membrane-bound envelope glycoprotein (Env) were tested in a phase 2a trial in human immunodeficiency virus (HIV)-uninfected adults for safety, immunogenicity, and 6-month durability of immune responses. METHODS A total of 299 individuals received 2 doses of JS7 DNA vaccine and 2 doses of MVA/HIV62B at 0, 2, 4, and 6 months, respectively (the DDMM regimen); 3 doses of MVA/HIV62B at 0, 2, and 6 months (the MMM regimen); or placebo injections. RESULTS At peak response, 93.2% of the DDMM group and 98.4% of the MMM group had binding antibodies for Env. These binding antibodies were more frequent and of higher magnitude for the transmembrane subunit (gp41) than the receptor-binding subunit (gp120) of Env. For both regimens, response rates were higher for CD4(+) T cells (66.4% in the DDMM group and 43.1% in the MMM group) than for CD8(+) T cells (21.8% in the DDMM group and 14.9% in the MMM group). Responding CD4(+) and CD8(+) T cells were biased toward Gag, and >70% produced 2 or 3 of the 4 cytokines evaluated (ie, interferon γ, interleukin 2, tumor necrosis factor α, and granzyme B). Six months after vaccination, the magnitudes of antibodies and T-cell responses had decreased by <3-fold. CONCLUSIONS DDMM and MMM vaccinations with virus-like particle-expressing immunogens elicited durable antibody and T-cell responses.
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Affiliation(s)
| | - Marnie L Elizaga
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center
| | - Kelly Seaton
- Laboratory for AIDS Vaccine Research and Development, Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Georgia D Tomaras
- Laboratory for AIDS Vaccine Research and Development, Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - David C Montefiori
- Laboratory for AIDS Vaccine Research and Development, Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Alicia Sato
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center
| | - John Hural
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center
| | - Stephen C DeRosa
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center University of Washington, Seattle, Washington
| | - Spyros A Kalams
- Vanderbilt University School of Medicine, Nashville, Tennessee
| | - M Juliana McElrath
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center University of Washington, Seattle, Washington
| | - Michael C Keefer
- University of Rochester School of Medicine and Dentistry, Rochester
| | - Lindsey R Baden
- Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Javier R Lama
- Asociacion Civil IMPACTA Salud y Educacion, Lima, Peru
| | - Jorge Sanchez
- Asociacion Civil IMPACTA Salud y Educacion, Lima, Peru
| | | | | | | | | | | | | | - Bernard Moss
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
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Prendergast AJ, Klenerman P, Goulder PJR. The impact of differential antiviral immunity in children and adults. Nat Rev Immunol 2012; 12:636-48. [PMID: 22918466 DOI: 10.1038/nri3277] [Citation(s) in RCA: 132] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The course of immune maturation has evolved to favour survival at each stage of development in early life. Fetal and neonatal immune adaptations facilitate intrauterine survival and provide early postnatal protection against extracellular pathogens, but they leave infants susceptible to intracellular pathogens such as viruses that are acquired perinatally. This Review focuses on three such pathogens--HIV, hepatitis B virus and cytomegalovirus--and relates the differential impact of these infections in infants and adults to the antiviral immunity that is generated at different ages. A better understanding of age-specific antiviral immunity may inform the development of integrated prevention, treatment and vaccine strategies to minimize the global disease burden resulting from these infections.
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Affiliation(s)
- Andrew J Prendergast
- Centre for Paediatrics, Blizard Institute, Queen Mary University of London, Newark Street, London E1 2AT, UK
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Abstract
The complex interplay between the host immune response and HIV has been the subject of intense research over the last 25 years. HIV and simian immunodeficiency virus (SIV) CD8 T cells have been of particular interest since they were demonstrated to be temporally associated with reduction in virus load shortly following transmission. Here, we briefly review the phenotypic and functional properties of HIV-specific and SIV-specific CD8 T-cell subsets during HIV infection and consider the influence of viral variation with specific responses that are associated with disease progression or control. The development of an effective HIV/AIDS vaccine combined with existing successful prevention and treatment strategies is essential for preventing new infections. In the context of previous clinical HIV/AIDS vaccine trials, we consider the challenges faced by therapeutic and vaccine strategies designed to elicit effective HIV-specific CD8 T cells.
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