TLR2 and infection: This shedding from macrophages is mediated by proteases in response to activation via protein C kinase, ATP, ligation of TLR2 or dectin-1 or after infection with e.g., Candida albicans, Aspergillus fumigatus, Pneumocystis jirovecii, and E. coli,56,57,58,59 but the mechanism is unknown.