Selected Grantee Publications
Allogeneic Immunity Clears Latent Virus Following Allogeneic Stem Cell Transplantation in SIV-Infected ART-Suppressed Macaques
Wu et al., Immunity. 2023.
https://doi.org/10.1016/j.immuni.2023.04.019
Allogeneic hematopoietic stem cell transplantation (alloHSCT) has been documented as curative for HIV, but the mechanisms are not yet known. Using Mauritian cynomolgus macaques of both sexes, researchers performed reduced-intensity alloHSCT experiments to define the individual contributions of allogeneic immunity and CCR5 deficiency to an alloHSCT-mediated HIV cure. They reported that allogeneic immunity was the major driver of reservoir clearance, mediating graft-versus-reservoir effects in HIV infection. Their results also point to a protective mechanism for CCR5 deficiency early during engraftment. Future efforts could focus on harnessing the beneficial effects of allogeneic immunity while avoiding graft-versus-host disease. Supported by ORIP (P51OD011092) and NIAID.
Osteopontin Is an Integral Mediator of Cardiac Interstitial Fibrosis in Models of Human Immunodeficiency Virus Infection
Robinson et al., The Journal of Infectious Diseases. 2023.
https://www.doi.org/10.1093/infdis/jiad149
HIV infection is associated with increased risk of cardiovascular disease. Plasma osteopontin (Opn) is correlated with cardiac pathology, but more work is needed to understand the underlying mechanisms driving cardiac fibrosis. Researchers explored this topic using mouse embryonic fibroblasts, male macaques, and humanized mice of both sexes. They reported the accumulation of Opn in the heart with simian immunodeficiency virus infection. Systemic inhibition of Opn can prevent HIV-associated interstitial fibrosis in the left ventricle. These findings suggest that Opn could be a potential target for adjunctive therapies to reduce cardiac fibrosis in people with HIV. Supported by ORIP (P51OD011104), NIAID, NHLBI, NIMH, and NINDS.
GluN2B Inhibition Confers Resilience against Long-Term Cocaine-Induced Neurocognitive Sequelae
Li et al., Neuropsychopharmacology. 2023.
https://www.nature.com/articles/s41386-022-01437-8
Cocaine self-administration can disrupt the capacity of humans and rodents to flexibly modify familiar behavioral routines, but effects on mechanistic factors—particularly those driving long-term behavioral changes—have not been characterized fully. Researchers used mice to examine the flexibility of decision-making behavior with oral cocaine self-administration. They found that GluN2B inhibition prevented cocaine-induced dysregulation of neuronal structure and function in the orbitofrontal cortex (OFC), preserving mature, mushroom-shaped dendritic spine densities on deep-layer pyramidal neurons. These findings suggest that cocaine potentiates GluN2B-dependent signaling, which triggers a series of durable adaptations that result in the dysregulation of post-synaptic neuronal structure in the OFC, ultimately weakening the capacity for flexible choice. Supported by ORIP (P51OD011132) and NINDS.
The Landscape of Tolerated Genetic Variation in Humans and Primates
Gao et al., Science. 2023.
Investigators created a whole-genome sequence database from 809 nonhuman primates (NHPs) of 233 species to test the hypothesis that gene variants that do not cause disease in NHPs would likely be benign also in humans. They found that 99% of the genetic variants that were benign in NHPs also were classified as benign in the human ClinVar database. In contrast, only 71% to 87% of genomic variants classified as benign in non-primate animals were benign in humans. Building on this approach, the authors reclassified more than 4 million human genetic variants of unknown health impact as likely being benign based on effects in NHPs. This work illustrates the power of comparative medicine approaches between NHPs and humans. Supported by ORIP (P40OD024628, P51OD011106) and NIGMS.
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.
Infection of the Maternal–Fetal Interface and Vertical Transmission Following Low-Dose Inoculation of Pregnant Rhesus Macaques (Macaca mulatta) with an African-Lineage Zika Virus
Koenig et al., PLOS ONE. 2023.
https://doi.org/10.1371/journal.pone.0284964
Researchers examined transmission of Zika virus to nonhuman primate fetuses during pregnancy. Even with a low dosage of inoculation of the dams, the investigators found that the Zika virus infected fetuses, despite the presence of a “placental fortress,” which normally protects fetuses during gestation. This transmission illustrates the high level of infectivity threat that Zika poses, which may increase if mosquitoes expand their global habitats. Understanding how Zika breaches the placental barrier will help researchers develop strategies to prevent fetal infection during pregnancy and thereby prevent adverse outcomes, such as brain malformation defects. Supported by ORIP (P51OD011106, S10OD023526), NIAID, NCI, and NIGMS.
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.