Selected Grantee Publications
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- 227 results found
- Nonhuman Primate Models
Prolonged Experimental CD4+ T-Cell Depletion Does Not Cause Disease Progression In SIV-Infected African Green Monkeys
Le Hingrat et al., Nature Communications. 2023.
https://www.nature.com/articles/s41467-023-36379-2
Chronically simian immunodeficiency virus (SIV)–infected African green monkeys (AGMs) partially recover mucosal CD4+ T cells, maintain gut integrity, and do not progress to AIDS. Investigators assessed the impact of prolonged, antibody-mediated CD4+ T cell depletion on gut integrity and natural history of SIV infection in AGMs. All circulating CD4+ T cells and more than 90% of mucosal CD4+ T cells were depleted. Plasma viral loads and cell-associated viral RNA in tissues were lower in CD4+-cell-depleted animals. CD4+-cell-depleted AGMs maintained gut integrity, controlled immune activation, and did not progress to AIDS. Therefore, CD4+ T cell depletion is not a determinant of SIV-related gut dysfunction when gastrointestinal tract epithelial damage and inflammation are absent, suggesting that disease progression and resistance to AIDS are independent of CD4+ T cell restoration in SIV-infected AGMs. Supported by ORIP (P40OD028116), NIAID, NIDDK, and NHLBI.
Alterations in Abundance and Compartmentalization of miRNAs in Blood Plasma Extracellular Vesicles and Extracellular Condensates during HIV/SIV Infection and its Modulation by Antiretroviral Therapy (ART) and Delta-9-Tetrahydrocannabinol (Δ9-THC)
Kopcho et al., Viruses. 2023.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10053514/
MicroRNAs (miRNAs) have been shown to regulate host response to HIV infection. Previously, investigators proposed that the assortment of extracellular miRNAs into distinct carriers could provide a new dimension to miRNA-based biomarkers. In this follow-up study, the investigators used particle purification liquid chromatography to determine the abundance and compartmentalization of blood plasma extracellular miRNAs into extracellular vesicles and extracellular condensates during simian immunodeficiency virus (SIV) infection in male rhesus macaques. They reported that different treatments—combination ART and Δ9‑THC—impart distinct effects on the enrichment and compartmentalization of extracellular miRNAs. These data suggest that the extracellular miRNA profile in blood plasma is altered following SIV infection. Supported by ORIP (P51OD011104, P51OD011133), NIAID, and NIDA.
CD8+ Lymphocytes Do Not Impact SIV Reservoir Establishment under ART
Statzu et al., Nature Microbiology. 2023.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9894752/
The HIV-1 latent reservoir has been shown to persist following antiretroviral therapy (ART), but the mechanisms underlying the establishment and maintenance of the reservoir are not fully understood. Using rhesus macaques of both sexes, investigators examined the effects of CD8+ T cells on formation of the latent reservoir with simian immunodeficiency virus (SIV) infection. They found that CD8+ T cell depletion resulted in slower decline of viremia but did not change the frequency of infected CD4+ T cells in the blood or lymph nodes. Additionally, the size of the persistent reservoir was unchanged. These findings suggest that the viral reservoir is established largely independent of SIV-specific cytotoxic T lymphocyte control. Supported by ORIP (P51OD011132), NIAID, NCI, NIDDK, NIDA, NHLBI, and NINDS.
Impaired Placental Hemodynamics and Function in a Non-Human Primate Model of Gestational Protein Restriction
Lo et al., Scientific Reports. 2023.
https://www.nature.com/articles/s41598-023-28051-y
Maternal malnutrition is a global health epidemic that adversely affects fetal outcomes and results in long-term health complications in children. Investigators used a previously developed model in nonhuman primates for gestational protein restriction to study the impact of undernutrition, specifically protein deficiency, on placental function and pregnancy outcomes. The data demonstrate that a 50% protein-restricted diet reduces maternal placental perfusion, decreases fetal oxygen availability, and increases fetal mortality. These alterations in placental hemodynamics could partly explain human growth restriction and stillbirth seen with severe protein restriction in developing countries. Supported by ORIP (P51OD011092) and NICHD.
Duration of Antiretroviral Therapy Impacts the Degree of Residual SIV Infection in the Gut in Long‐Term Non‐Progressing Chinese Rhesus Macaques
Solis-Leal et al., Journal of Medical Virology. 2023.
https://onlinelibrary.wiley.com/doi/abs/10.1002/jmv.28185
HIV and simian immunodeficiency virus (SIV) reservoirs have been shown to persist with antiretroviral therapy (ART), particularly in the gut‐associated lymphoid tissues in the intestine. The effects of ART on the reservoir size, however, had not been explored fully. In this study, researchers used male Chinese‐origin rhesus macaques to assess the effects of long- and short-term ART on gut infection—across segments of the small and large intestines—in long‐term non‐progressors (LTNPs). They reported that although ART does not eliminate SIV in LTNPs, a longer ART period dramatically reduces SIV infection and diversity in the gut. Further studies are needed to better understand the reduction of HIV gut reservoirs in this context. Supported by ORIP (P51OD011133, P51OD011104), NIAID, NIMH, and NINDS.
Recombinant Simian Varicella Virus–Simian Immunodeficiency Virus Vaccine Induces T and B Cell Functions and Provides Partial Protection Against Repeated Mucosal SIV Challenges in Rhesus Macaques
Pahar et al., Viruses. 2022.
https://www.doi.org/10.3390/v14122819
An effective vaccine is needed urgently to control the global HIV epidemic completely by 2030. Recombinant simian varicella virus (rSVV) vaccines expressing SIV antigens offer a potential new approach in the evaluation of HIV vaccine candidates. Building on their previous findings, the investigators induced systemic and mucosal immune responses with live, attenuated rSVV vaccinations followed by SIV group–specific antigen and SIV envelope protein boosts in female rhesus macaques treated with repeated intravaginal SIV challenges. Their findings demonstrate that the vaccination with protein boosts induces a 37.5% efficacy rate against pathogenic SIV challenge by generating mucosal memory, virus‑specific neutralizing antibodies, binding antibodies, and polyfunctional T cell responses. Supported by ORIP (P51OD011104) and NIAID.
Transient T Cell Expansion, Activation, and Proliferation in Therapeutically Vaccinated Simian Immunodeficiency Virus–Positive Macaques Treated with N-803
Harwood et al., Journal of Virology. 2022.
https://www.doi.org/10.1128/jvi.01424-22
Many HIV vaccine strategies induce neutralizing antibodies and CD8+ T cells, but more information on these protective immune responses is needed. Researchers hypothesized that CD8+ T cells elicited by vaccination during antiretroviral therapy (ART) would be recalled and boosted by treatment with N-803 after ART discontinuation. They tested this approach in male Mauritian cynomolgus macaques infected with simian immunodeficiency virus. The regimen enhanced the frequency of Gag-specific lymphocytes with phenotypes associated with activation, proliferation, and memory in the peripheral blood and lymph nodes of vaccinated animals. These results help demonstrate N-803’s potential as an immunomodulatory agent for treatment of HIV. Supported by ORIP (P51OD011106) and NIAID.
Sociability in a Non-Captive Macaque Population Is Associated with Beneficial Gut Bacteria
Johnson et al., Frontiers in Microbiology. 2022.
https://www.doi.org/10.3389/fmicb.2022.1032495
Social connections are essential for good health and well-being in social animals, such as humans and other primates. Increasingly, evidence suggests that the gut microbiome—through the so-called “gut–brain axis”—plays a key role in physical and mental health and that bacteria can be transmitted socially (e.g., through touch). Here, the authors explore behavioral variation in non‑captive rhesus macaques of both sexes with respect to the abundance of specific bacterial genera. Their results indicate that microorganisms whose abundance varies with individual social behavior also have functional links to host immune status. Overall, these findings highlight the connections between social behavior, microbiome composition, and health in an animal population. Supported by ORIP (P40OD012217) and NIMH.
SARS-CoV-2 Infects Neurons and Induces Neuroinflammation in a Non-Human Primate Model of COVID-19
Beckman et al., Cell Reports. 2022.
https://www.doi.org/10.1016/j.celrep.2022.111573
SARS-CoV-2 causes brain fog and other neurological complications in some patients. It has been unclear whether SARS-CoV-2 infects the brain directly or whether central nervous system sequelae result from systemic inflammatory responses triggered in the periphery. Using a rhesus macaque model, researchers detected SARS-CoV-2 in the olfactory cortex and interconnected regions 7 days after infection, demonstrating that the virus enters the brain through the olfactory nerve. Neuroinflammation and neuronal damage were more severe in elderly monkeys with type 2 diabetes. The researchers found that in aged monkeys, SARS-CoV-2 traveled farther along nerve pathways to regions associated with Alzheimer's disease. Supported by ORIP (P51OD011107) and NIA.
Long-Term Evolutionary Adaptation of SIVcpz toward HIV-1 Using a Humanized Mouse Model
Schmitt et al., Journal of Medical Primatology. 2022.
https://www.doi.org/10.1111/jmp.12616
Chimpanzee-derived simian immunodeficiency viruses (SIVcpz) are thought to have evolved into the highly pathogenic HIV-1 Group M, but the genetic adaptations required for SIV progenitor viruses to become pathogenic and established as HIVs in the human population have remained unclear. Using humanized mice of both sexes, researchers mimicked the evolution of SIVcpz into HIV-1 Group M through serial passaging. After four generations, the researchers observed increased initial viral load, increased CD4+ T cell decline, and nonsynonymous substitutions. Overall, these data indicate increased viral fitness and pathogenicity. This work also demonstrates the utility of humanized mice in recreating the adaptive pressures necessary for the evolution of SIVcpz into HIV-1. Supported by ORIP (P51OD011104, P51OD011106), NCATS, and NIAID.