Selected Grantee Publications
Deep Analysis of CD4 T Cells in the Rhesus CNS During SIV Infection
Elizaldi et al., PLOS Pathogens. 2023.
https://pubmed.ncbi.nlm.nih.gov/38060615/
Systemic HIV infection results in chronic inflammation that causes lasting damage to the central nervous system (CNS), despite long-term antiretroviral therapy (ART). Researchers studied neurocognitive outcomes in male and female rhesus macaques infected with simian immunodeficiency virus (SIV) using an ART regimen simulating suboptimal adherence; one group received no ART, and the other received ART with periodic interruptions. Using single-cell transcriptomic profiling, the researchers also identified molecular programs induced in the brain upon infection. They found that acute infection led to marked imbalance in the CNS CD4/CD8 T‑cell ratio, which persisted into the chronic phase. The studies provide insight into the role of CD4 T cells in the CNS during HIV infection. Supported by ORIP (P51OD011107, K01OD023034), NIA, NIAID, and NCI.
Lymphoid Tissues Contribute to Plasma Viral Clonotypes Early After Antiretroviral Therapy Interruption in SIV-Infected Rhesus Macaques
Solis-Leal et al., Science Translational Medicine. 2023.
https://pubmed.ncbi.nlm.nih.gov/38091409/
Researchers are interested in better understanding the sources, timing, and mechanisms of HIV rebound that occurs after interruption of antiretroviral therapy (ART). Using rhesus macaques (sex not specified), investigators tracked barcoded simian immunodeficiency virus (SIV) clonotypes over time and among tissues. Among the tissues studied, mesenteric lymph nodes, inguinal lymph nodes, and spleen contained viral barcodes detected in plasma. Additionally, the authors reported that CD4+ T cells harbored the most viral RNA after ART interruption. These tissues are likely to contribute to viral reactivation and rebound after ART interruption, but further studies are needed to evaluate the relative potential contributions from other tissues and organs. Supported by ORIP (P51OD011104, P51OD011133, S10OD028732, S10OD028653), NCI, NIMH, and NINDS.
Timing of Initiation of Anti-Retroviral Therapy Predicts Post-Treatment Control of SIV Replication
Pinkevych et al., PLOS Pathogens. 2023.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10558076/
Researchers are interested in approaches to reducing viral rebound following interruption of antiretroviral therapy, but more work is needed to understand major factors that determine the viral “setpoint” level. Researchers previously assessed how timing of treatment can affect the frequency of rebound from latency. In the current study, the authors analyzed data from multiple studies of simian immunodeficiency virus (SIV) infection in rhesus macaques to further explore the dynamics and predictors of post-treatment viral control. They determined that the timing of treatment initiation was a major predictor of both the level and the duration of post-rebound SIV control. These findings could help inform future treatments. Supported by ORIP (U42OD011023, P51OD011132, P51OD011092), NIAID, NCI, NIDA, NIDDK, NHLBI, NIMH, and NINDS
CD8+ Cells and Small Viral Reservoirs Facilitate Post-ART Control of SIV Replication in M3+ Mauritian Cynomolgus Macaques Initiated on ART Two Weeks Post-Infection
Harwood et al., PLOS Pathogens. 2023.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10553806/
A rare group of people infected with HIV can achieve sustainable HIV remission after antiretroviral therapy (ART) withdrawal, but the underlying mechanisms are not understood fully. A team of investigators observed post-treatment control in a cohort of male cynomolgus macaques that were initiated on ART 2 weeks post-infection. Additionally, they reported that the cynomolgus macaques had smaller acute reservoirs than similarly infected rhesus macaques. Collectively, these data suggest that a combination of small reservoirs and immune-mediated virus suppression contributes to post-treatment control in cynomolgus macaques. This model could be used in future studies to develop therapeutic interventions. Supported by ORIP (P51OD011106, P40OD028116), NIAID, and NCI.
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.
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.
Cerebrospinal Fluid Protein Markers Indicate Neuro-Damage in SARS-CoV-2-Infected Nonhuman Primates
Maity et al., Molecular & Cellular Proteomics. 2023.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9981268/
In this study, researchers examined the proteins expressed in cerebrospinal fluid (CSF) in nonhuman primates (NHPs) to better understand how COVID-19 infection can result in brain pathology, a common outcome. The study found that even in NHPs with minimal or mild COVID‑19, CSF proteins were significantly dysregulated compared with uninfected NHPs. Furthermore, the most affected proteins were enriched in the same brain regions that show lesions after COVID-19 infection, including the cerebral cortex, basal ganglia, and brain stem. Collectively, these regions have wide-ranging control over such crucial functions as cognition, motor control, and breathing, showing how even mild COVID-19 infection can result in significant neurological impairment. Supported by ORIP (P51OD011104, S10OD032453), NIGMS, NCI, and NICHD.
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.