Fig. 3From: HIV and the tuberculosis “set point”: how HIV impairs alveolar macrophage responses to tuberculosis and sets the stage for progressive diseaseEvents in alveolar macrophage uptake and response to Mtb infection that are impacted by HIV coinfection. (1) Recognition: HIV coinfection downregulates alveolar macrophage expression of Mtb recognition receptors including mannose and toll-like receptors. (2) Uptake and phagocytosis: HIV coinfection impairs phagocytosis. (3) Phagolysosomal fusion: HIV coinfection disrupts endosomal trafficking and impairs phagolysosomal maturation. (4) Antigen presentation: HIV coinfection leads to the expression of immature MHC class II complexes and thereby impairs the activation of adaptive immune responses. (5) Activation of adaptive immunity: HIV coinfection reduces the expression of costimulatory molecules for activation of adaptive immunity. The net effect of these HIV-mediated impairments is to enable increased intracellular and extracellular Mtb growth which ultimately leads to a higher mycobacterial set pointBack to article page