부산대학교 도서관

HIV associated immune activation (IA) is associated with increased morbidity in people living with HIV (PLWH) on antiretroviral therapy, and remains a barrier for strategies aimed at reducing the HIV reservoir. The underlying mechanisms of IA have not been definitively elucidated, however, persistent production of Type I IFNs and expression of ISGs is considered to be one of the primary factors. Plasmacytoid DCs (pDCs) are a major producer of Type I IFN during viral infections, and are highly immunomodulatory in acute HIV and SIV infection, however their role in chronic HIV/SIV infection has not been firmly established. Here, we performed a detailed transcriptomic characterization of pDCs in chronic SIV infection in rhesus macaques, and in sooty mangabeys, a natural host non-human primate (NHP) species that undergoes non-pathogenic SIV infection. We also investigated the immunostimulatory capacity of lymph node homing pDCs in chronic SIV infection by contrasting gene expression of pDCs isolated from lymph nodes with those from blood. We observed that pDCs in LNs, but not blood, produced high levels of IFNα transcripts, and upregulated gene expression programs consistent with T cell activation and exhaustion. We apply a novel strategy to catalogue uncharacterized surface molecules on pDCs, and identified the lymphoid exhaustion markers TIGIT and LAIR1 as highly expressed in SIV infection. pDCs from SIV-infected sooty mangabeys lacked the activation profile of ISG signatures observed in infected macaques. These data demonstrate that pDCs are a primary producer of Type I IFN in chronic SIV infection. Further, this study demonstrated that pDCs trafficking to LNs persist in a highly activated state well into chronic infection. Collectively, these data identify pDCs as a highly immunomodulatory cell population in chronic SIV infection, and a putative therapeutic target to reduce immune activation. Author summary: For people living with HIV (PLWH), persistent immune activation is an obstacle to optimal health. In this study, we investigate the immunostimulatory potential of plasmacytoid dendritic cells in chronic SIV infection using comparative RNA-Seq. We observed that pDCs from SIV-infected rhesus macaques have highly activated profiles relative to uninfected animals; in contrast, pDCs from SIV-infected natural host sooty mangabeys had expression profiles similar to cells from uninfected animals. In chronically infected RMs, pDCs from lymph nodes maintained activation profiles elevated at levels even higher than those in the blood. Further, transcripts for the immunostimulatory cytokine family IFNA were readily detected in LN homing pDCs, but not those from blood. These data confirm pDCs as a major producer of Type I IFN in chronic SIV infection, and identify them as a target for immunotherapy. [ABSTRACT FROM AUTHOR]