Receptor-mediated recognition of mycobacterial pathogens

Mycobacteria are a genus of bacteria that range from the non-pathogenic Mycobacterium smegmatis to Mycobacterium tuberculosis, the causative agent of tuberculosis in humans. Mycobacteria primarily infect host tissues through inhalation or ingestion. They are phagocytosed by host macrophages and dendritic cells. Here, conserved pathogen-associated molecular patterns (PAMPs) on the surface of mycobacteria are recognized by phagocytic pattern recognition receptors (PRRs). Several families of PRRs have been shown to non-opsonically recognize mycobacterial PAMPs, including membrane-bound C-type lectin receptors, membrane-bound and cytosolic Toll-like receptors and cytosolic NOD-like receptors. Recently, a possible role for intracellular cytosolic PRRs in the recognition of mycobacterial pathogens has been proposed. Here, we discuss current ideas on receptor-mediated recognition of mycobacterial pathogens by macrophages and dendritic cells.