Selected Grantee Publications
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- 151 results found
- Immunology
- P51
Brain Microglia Serve as a Persistent HIV Reservoir Despite Durable Antiretroviral Therapy
Tang et al., The Journal of Clinical Investigation. 2023.
https://www.doi.org/10.1172/JCI167417
Brain microglia are likely to play a role in rebound viremia following the cessation of antiretroviral therapy, but more work is needed to fully understand HIV persistence in the central nervous system (CNS). The investigators developed a protocol to isolate highly pure populations of brain myeloid cells and microglia from the tissues of male rhesus macaques, as well as from rapid autopsies of men and women with HIV. Their observations support the concept that brain microglia are a stable reservoir of quiescent infection. Thus, this work provides a physiologically relevant platform for studies of the biology of CNS reservoirs. Supported by ORIP (P51OD011132), NIAID, and NIMH.
Lymph-Node-Based CD3+ CD20+ Cells Emerge From Membrane Exchange Between T Follicular Helper Cells and B Cells and Increase Their Frequency Following Simian Immunodeficiency Virus Infection
Samer et al., Journal of Virology. 2023.
https://www.doi.org/10.1128/jvi.01760-22
CD4+ T follicular helper cells are known to persist during antiretroviral therapy (ART) and have been identified as key targets for viral replication and persistence. Researchers identified a lymphocyte population that expresses CD3 (i.e., T cell lineage marker) and CD20 (i.e., B cell lineage marker) on the cellular surface in lymphoid tissues from rhesus macaques of both sexes and humans of male and female sexes. In macaques, the cells increased following simian immunodeficiency virus infection, were reduced with ART, and increased in frequency after ART interruption. These cells represent a potential area for future therapeutic strategies. Supported by ORIP (P51OD011132, U42OD011023), NIAID, NCI, NIDDK, NIDA, NHLBI, and NINDS.
Antibody-Dependent Cellular Cytotoxicity, Infected Cell Binding and Neutralization by Antibodies to the SIV Envelope Glycoprotein
Grunst et al., PLOS Pathogens. 2023.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10256149/
Antibodies that bind to the envelope glycoprotein (Env) on the surface of virus-infected cells can recruit cells from the immune system to kill infected cells by antibody-dependent cellular cytotoxicity (ADCC). Researchers characterized ADCC, Env binding, and neutralization in rhesus macaque antibodies that were specific for diverse epitopes of the simian immunodeficiency virus (SIV) envelope glycoprotein. They found that most antibodies that inhibit SIV infectivity also bind to Env on infected cells and mediate ADCC, but this trend was not observed in select instances. Based on these findings, the authors suggest that some antibody–Env interactions can uncouple antiviral activities. Supported by ORIP (P51OD011106) and NIAID.
Efficient Ex Vivo Expansion of Conserved Element Vaccine-Specific CD8+ T Cells from SHIV-Infected, ART-Suppressed Nonhuman Primates
Dross et al., Frontiers in Immunology. 2023.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10189133/
HIV-specific T cells are necessary for control of HIV-1 replication but are largely insufficient for viral clearance. Using male rhesus macaques, investigators sought to increase the frequency of specific T cell responses in vivo using an ex vivo cell manufacturing approach. The resulting products contained high frequencies of specific, polyfunctional T cells, but no significant differences in T cell persistence were observed, nor was acquisition of simian–human immunodeficiency virus (SHIV). This work underscores this animal model as an important approach to optimize the manufacturing of antigen-specific immune effectors that can prevent virus acquisition and control viral rebound after discontinuing antiretroviral therapy (ART). Supported by ORIP (P51OD010425, U42OD011123), NIAID, and NCI.
Complement Contributes to Antibody-Mediated Protection Against Repeated SHIV Challenge
Goldberg et al., PNAS. 2023.
The first clinical efficacy trials of a broadly neutralizing antibody (bNAb) resulted in less benefit than expected and suggested that improvements are needed to prevent HIV infection. Using rhesus macaques of both sexes, investigators sought to further investigate the contribution of antibody-mediated activation of complement to the protective potency of an HIV bNAb in passive transfer and simian–human immunodeficiency virus (SHIV) challenge experiments. They observed that fewer bNAbs were required to protect animals from plasma viremia when complement activity was enhanced, suggesting that complement-mediated effector functions contribute to in vivo antiviral activity and might contribute to further improvements in the efficacy of antibody-mediated prevention strategies. Supported by ORIP (P51OD011092, U42OD023038) and NIAID.
Probiotic Therapy During Vaccination Alters Antibody Response to Simian-Human Immunodeficiency Virus Infection But Not to Commensals
Wilson et al., AIDS Research and Human Retroviruses. 2023.
https://www.doi.org/10.1089/AID.2022.0123
Strategies to boost vaccine-induced mucosal humoral responses are critical to developing an HIV-1 vaccine, and probiotic supplementation could help boost antibody responses. Researchers analyzed antibody titers to explore this topic in rhesus macaques (sex not specified) infected with simian–human immunodeficiency virus (SHIV). They reported that probiotic treatment during vaccination led to delayed kinetics in the circulating HIV-specific IgA response after breakthrough SHIV infection. These findings highlight the potential of probiotic supplementation for reducing IgA-specific HIV antibodies in the plasma, which could help reduce HIV acquisition in vaccinated individuals. Supported by ORIP (P51OD011104, R21OD031435) and NIAID.
HIV, Asymptomatic STI, and the Rectal Mucosal Immune Environment Among Young Men Who Have Sex With Men
Van Doren et al., PLOS Pathogens. 2023.
https://www.doi.org/10.1371/journal.ppat.1011219
Young men who have sex with men (YMSM) are affected disproportionately by HIV and bacterial sexually transmitted infections (STIs) and therefore are likely to face an increased burden of associated chronic inflammation. Researchers studied the immunologic effects and interactions of HIV and bacterial STIs, as well as their effects on the rectal mucosal immune environment, among various populations of YMSM. Their findings suggest that asymptomatic bacterial STIs could contribute to inflammation, particularly among YMSM with HIV. This study provides insights into the immunopathogenesis of asymptomatic bacterial STIs and identifies a syndemic interaction between HIV and bacterial STIs in YMSM. Supported by ORIP (P51OD011132), NIAID, and NICHD.
CD8+ T Cells Promote HIV Latency by Remodeling CD4+ T Cell Metabolism to Enhance Their Survival, Quiescence, and Stemness
Mutascio et al., Immunity. 2023.
https://www.doi.org/10.1016/j.immuni.2023.03.010
An HIV reservoir persists following antiretroviral therapy, representing the main barrier to an HIV cure. Using a validated in vitro model, investigators explored the mechanism by which CD8+ T cells promote HIV latency and inhibit latency reversal in HIV-infected CD4+ T cells. They reported that CD8+ T cells favor the establishment of HIV latency by modulating metabolic, stemness, and survival pathways that correlate with the downregulation of HIV expression and promote HIV latency. In future studies, comparative analyses may provide insight into common molecular mechanisms in the silencing of HIV expression by CD8+ T cells and macrophages, which can be applied to new intervention strategies that target the HIV reservoir. Supported by ORIP (P51OD011132, S10OD026799), NIAID, NIDDK, NIDA, NHLBI, and NINDS.
Infant Rhesus Macaques Immunized Against SARS-CoV-2 Are Protected Against Heterologous Virus Challenge 1 Year Later
Milligan et al., Science Translational Medicine. 2023.
https://doi.org/10.1126/scitranslmed.add6383
The Moderna and Pfizer–BioNTech mRNA vaccines received emergency use authorization for infants 6 months and older in June 2022, but questions remain regarding the durability of vaccine efficacy against emerging variants in this age group. Using a two-dose vaccine regimen consisting of stabilized prefusion Washington-strain spike protein encoded by mRNA and encapsulated in lipid nanoparticles, the investigators immunized 2-month-old rhesus macaques of both sexes. They found that the immune responses persisted and protected from severe disease after heterologous challenge with the Delta variant 1 year later. The decay kinetics of vaccine-induced neutralizing antibody responses in the infant monkeys are comparable to those observed in adult humans and nonhuman primates. Supported by ORIP (P51OD011107), NIAID, and NCI.
Late Gene Expression–Deficient Cytomegalovirus Vectors Elicit Conventional T Cells That Do Not Protect Against SIV
Hansen et al., Journal of Clinical Investigation Insight. 2023.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10070102/
Cytomegalovirus (CMV)–based vaccines aim to exploit unique immunological adaptations, including host manipulation and immune evasion strategies. Translating CMV-based vaccines from rhesus macaques to humans requires translating the immune factors responsible for efficacy, as well as vaccine vectors that are sufficiently safe for widespread use. Researchers examined the impact of a stringent attenuation strategy on vector-induced immune protection against simian immunodeficiency virus (SIV) in rhesus macaques of both sexes. They reported that elicited CD8+ T cells exclusively failed to protect against SIV challenge. These data suggest that late viral gene expression and/or residual in vivo spreading are required to induce protective CD8+ T cell responses. Supported by ORIP (P51OD011092, P51OD011107, S10OD016261), NCI, NIAID, and NCATS.