Variations in the main virologic and immunologic markers of HIV/SIV infection during the course of pathogenic HIV/SIV infections in humans (black lines) and RM (blue lines), and nonprogressive SIV infection in SM (red lines) and AGM (green lines). (A) Levels of viral replication (solid lines) and immune activation (dotted lines), defined as levels of T- and B-cell activation/proliferation, Interferon stimulates gene response, type I interferon production. (B) Levels of CD4 T cells in peripheral blood (solid lines) and gastrointestinal tracts (mucosa-associated lymphoid tissue [MALT], dotted lines). (C) Levels of mucosal Th17 cells (solid lines, defined as IL-17–producing CD4 T cells) and integrity of the epithelial barrier at the mucosal level (dotted lines). Data on epithelial barrier integrity during the acute phase of infection are available only for RM.