Chronic innate immune activation as a cause of HIV-1 immunopathogenesis.
Human immunodeficiency virus (HIV)-1 infection causes progressive impairment of the immune system in humans, characterized by depletion of CD4 T cells and loss of T cell function. Increased markers of T cell activation and lymphoid hyperplasia suggest that chronic T cell activation persists in immunocompromised hosts, and contributes to the exhaustion of immune functions. Here we propose a revision of this hypothesis, in which we suggest that chronic activation of innate immunity may negatively affect adaptive T cell-mediated responses. We hypothesize that constant exposure of the effector cells of innate immunity to HIV results in their chronic hyperactivation, with deleterious effects on T cells. In particular, plasmacytoid dendritic cells (pDC) may be highly susceptible to HIV-induced activation due to its interaction with the cellular receptor CD4, expressed by pDC. Subsequent production of type I interferon and indoleamine 2,3-dioxygenase may exert suppressive and cytotoxic effects on T cells.
Boasso
Adriano
A
Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892, USA. boassoa@mail.nih.gov
Shearer
Gene M
GM
D003713:Dendritic Cells / Q000276:immunology; D015658:HIV Infections / Q000276:immunology* / Q000473:pathology* / Q000821:virology; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology*; D018448:Models, Immunological