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Chronic HIV replication occurs primarily within lymphoid follicles, and investigators hypothesized that temporary disruption of these follicles would create space for chimeric antigen receptor (CAR) T cell engraftment and lead to increased abundance and persistence of CAR T cells. They evaluated CAR T cell abundance and persistence in rhesus macaques of both sexes following simian immunodeficiency virus (SIV) infection and antiretroviral therapy suppression. Their results suggest that CAR T cells expanded to a greater extent in the depleted and CAR T cell–treated animals.
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MicroRNAs (miRNAs) are thought to be involved in HIV pathogenesis, but the effect of HIV on the compartmentalization of miRNAs within extracellular particles is unclear. Researchers sequenced the small RNA population of paired EVs and ECs from male rhesus macaques. They showed that extracellular miRNAs in blood plasma are not restricted to any type of extracellular particles but are associated with lipid‑based carriers, with a significant proportion associated with ECs.
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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.
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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.
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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.
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A major obstacle to human natural killer (NK) cell reconstitution is the lack of human interleukin‑15 (IL-15) signaling, as murine IL-15 is a poor stimulator of the human IL-15 receptor. Researchers show that immunodeficient NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice expressing a transgene encoding human IL-15 (NSG-Tg(IL-15)) have physiological levels of human IL-15 and support long-term engraftment of human NK cells when transplanted with human umbilical cord blood–derived hematopoietic stem cells (HSCs).
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Researchers have previously observed that human pegivirus (HPgV) infection is associated with reduced progression of HIV. Investigators examined markers of HIV progression in male and female individuals with HIV and HPgV infection. They reported that HIV plasma viral load was lower in HPgV-seropositive individuals with HIV than in HPgV‑seronegative individuals with HIV. They also found that clinical markers of hepatic damage were significantly lower in HPgV-seropositive individuals with HIV.
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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).
As an immunologist studying HIV, latent tuberculosis infection (LTBI), and possible treatments, Dr. Riti Sharan (Figure 1) has been intrigued by the human body since high school, particularly the complex and varied mechanisms by which it defends itself against pathogens.
In 2015 and 2016, the Zika virus outbreak in South America surprised the global community. In pregnant women, the virus led to a high rate of fetal abnormalities, collectively called congenital Zika syndrome. Babies suffered from such birth defects as microcephaly, which is characterized by a small head and an incompletely developed brain. Although the peak of the outbreak has passed, the risk of another outbreak remains because transmission occurs primarily via infected mosquitos.
