TLR1 and infection: TLRs 1-9 expressed by microglia. TLRs 2,4,7,9 involved in microglial phagocytosis of fibrillar Aβ42 and various TLRs in recognition of pathogens. TLR stimulation enhances microglial phagocytosis of pathogens myelin antigen presentation apoptotic cells and axonal debris. Astrocytes express TLR3 + low levels of TLR1-5/9. Upregulated in response to cytokines, bacterial ligands and infection in vivo.