Timing of Initiation of Anti-Retroviral Therapy Predicts Post-Treatment Control of SIV Replication
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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.
AZD5582 Plus SIV-Specific Antibodies Reduce Lymph Node Viral Reservoirs in Antiretroviral Therapy–Suppressed Macaques
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Researchers are interested in targeting the HIV reservoir via a latency reversal and clearance approach. Previously, investigators demonstrated that AZD5582 induces systemic latency reversal in rhesus macaques and humanized mice, but a consistent reduction in the viral reservoir was not observed. In the current study, they combined AZD5582 with four simian immunodeficiency virus (SIV)–specific rhesus monoclonal antibodies using rhesus macaques of both sexes.
Biphasic Decay of Intact SHIV Genomes Following Initiation of Antiretroviral Therapy Complicates Analysis of Interventions Targeting the Reservoir
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The latent HIV-1 reservoir persists with antiretroviral therapy (ART), and assays for quantifying intact proviruses in nonhuman primate models are needed. Researchers used a simian–human immunodeficiency virus (SHIV) intact proviral DNA assay to describe viral decay during the first year of ART in female rhesus macaques. Their results suggest that intact SHIV genomes in circulating CD4+ T cells undergo biphasic decay during the first year of ART, with a rapid first phase and a slower second phase.
Enhanced IL-17 Producing and Maintained Cytolytic Effector Functions of Gut Mucosal CD161+ CD8+ T Cells in SIV-Infected Rhesus Macaques
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HIV infection is associated with the depletion of CD161-expressing CD4+ Th17 cells, but the effects on other IL-17–producing T cell subsets are not understood fully. Researchers characterized the functions of non-invariant CD161-expressing CD8+ T cell subpopulations in peripheral blood and mucosal tissues of rhesus macaques (sex not specified) during chronic simian immunodeficiency virus (SIV) infection.
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
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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.
The Latent Reservoir of Inducible, Infectious HIV-1 Does Not Decrease Despite Decades of Antiretroviral Therapy
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Antiretroviral therapy (ART) does not eliminate the latent HIV reservoir, but it is unknown whether sustained reservoir decay occurs with long-term ART. Researchers used a quantitative viral outgrowth assay, an intact proviral DNA assay, and proviral sequencing to characterize the latent reservoir in men and women with HIV who had maintained suppression of viral replication on ART for 14 to 27 years. They found that the reservoir decay did not continue with long-term ART. Further studies could provide insight into the mechanism underlying these findings.
Long-Acting Lenacapavir Protects Macaques Against Intravenous Challenge With Simian-Tropic HIV
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Pre-exposure prophylaxis (PrEP) is effective in preventing new HIV infections, but regimen adherence remains a challenge. Antiretrovirals with long-acting pharmacokinetic properties could help overcome this limitation. Researchers examined the protective efficacy of lenacapavir, a first-in-class HIV capsid inhibitor, using male pigtail macaques. They reported that a single administration of the drug provided protection from simian-tropic HIV infection.
Downregulation of CCR5 on Brain Perivascular Macrophages in Simian Immunodeficiency Virus–Infected Rhesus Macaques
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Researchers have been exploring multiple strategies to develop an HIV vaccine. In this study, the investigators determined the immunogenicity and efficacy of intradermal and intramuscular routes of modified vaccinia Ankara (MVA) vaccination in female rhesus macaques. They found that both routes of MVA vaccination enabled control of viral replication, but only the intradermal vaccination was effective in protection against viral acquisition. Their findings suggest that the intradermal MVA vaccinations provide protection by modulating the innate and T helper responses.
Antiretroviral Therapy Ameliorates Simian Immunodeficiency Virus–Associated Myocardial Inflammation by Dampening Interferon Signaling and Pathogen Response in the Heart
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HIV is associated with increased risk of cardiovascular disease, but the underlying mechanisms are not fully understood. Using RNA sequencing, investigators characterized the effects of simian immunodeficiency virus (SIV) infection on the hearts of male rhesus macaques. They demonstrated that SIV infection drives a canonical antiviral response in the heart, as well as dysregulation of genes involved in fatty acid shuttling and metabolism. Their findings suggest that antiretroviral therapy helps mitigate immune activation during viremic conditions and plays a cardioprotective role.