Heat-inactivated Parachlamydia acanthamoebae stimulates the production of proinflammatory cytokines by macrophages through TLR4 and, to a lesser extent, TLR2. The kinetics of TNF, IL-6, and IL-12p40 production by wild-type, TLR2−/−, and TLR4−/− BMDMs infected with live and heat-inactivated P. acanthamoebae (multiplicity of infection [MOI], 100) are shown. Data are means ± standard deviations (SD) for triplicate samples from one experiment and are representative of three independent experiments. *, P < 0.05 versus result for wild-type BMDMs.