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The usage of antiretroviral treatment (ART) has considerably decreased the morbidity and mortality related to HIV-1 (human immunodeficiency virus type 1) infection. However, ART is ineffective in eradicating the virus from the persistent cell reservoirs (e.g., microglia), noticeably hindering the cure for HIV-1. Microglia participate in the progression of neuroinflammation, brain aging, and HIV-1-associated neurocognitive disorder (HAND). Some methods have currently been studied as fundamental strategies targeting microglia. The purpose of this study was to comprehend microglia biology and its functions in HIV-1 infection, as well as to look into potential therapeutic approaches targeting microglia. [ABSTRACT FROM AUTHOR]

The dysfunction of memory CD8+ T cell cannot be reverted by successful clearance of hepatitis C virus (HCV) after direct-acting antivirals (DAAs) therapy, increasing the risk of reinfection with HCV. Stem cell-like memory T cells (Tscm) with superior properties of long-lasting, self-renewing, and multipotency contribute to the maintenance of immune function. We investigated the impact of HCV infection on CD8+ Tscm, and their possible role in disease progression, by using DAA-naive HCV-infected and human immunodeficiency virus (HIV)/HCV-coinfected cohorts. The distribution of memory CD8+ T cell subsets and the level of T cell immune activation were determined by flow cytometry. Associations between CD8+ Tscm and other memory T cell subsets, HCV viral load, as well as the level of T cell immune activation were analyzed. We observed that the proportion of CD8+ Tscm increased in both HCV and HIV/HCV individuals. The proportion of CD8+ Tscm had positive and negative correlation with CD8+ Tcm (central memory T cells) and CD8+ Tem (effector memory T cell), respectively, representing the contribution of CD8+ Tscm in T cell homeostasis. In addition, higher frequency of CD8+ Tscm indicated lower HCV viral load and less T cell immune activation in HCV infection, which suggested that CD8+ Tscm is likely associated with effective control of HCV replication for protective immunity. Considering the characteristics of Tscm, our current findings provide implications for Tscm-based vaccine design and immunotherapy development to achieve HCV elimination. [ABSTRACT FROM AUTHOR]

Recently identified T memory stem (Tscm) cells have stem-cell-like properties, including long lifespan, self-renewal capacity, and multipotency to differentiate into other memory T cell types. In the study of simian immunodeficiency virus (SIV) infection, selective depletion of CCR5+CD4+ Tscm cells and the high proliferation rate of these cells are believed to be responsible for the pathogenesis of SIV-infected rhesus macaques. Here, we conducted a cohort study to investigate the influence of chronic human immunodeficiency virus (HIV)-1 infection on CD4+ Tscm cell homeostasis, and the effect of antiretroviral therapy (ART) on CD4+ Tscm cells. Chronic HIV-1 infection resulted in a decrease of the CD4+ Tscm cell proportion in HIV-1 patients. The decreased number of CD4+ Tscm cells in HIV-1 patients correlated positively with that of circulating CD4+ T cells. Further, the depletion of CD4+ Tscm cells was inversely correlated with an increased level of T cell immune activation during chronic HIV-1 infection. Prolonged ART recovered the CD4+ Tscm cells, and the dynamic change of CD4+ Tscm cells was in parallel with CD4+ T cell restoration and a decrease in the level of T cell immune activation. We propose that the abnormity of CD4+ Tscm cells may contribute to the pathogenesis and disease progression in HIV-1-infected individuals. [ABSTRACT FROM AUTHOR]