Deficiency in TLR2 but not in TLR4 impairs dendritic cells derived IL-10 responses to schistosome antigens

The purpose of this study was to observe the diverse functions of Toll-like receptors (TLRs) in responses to specific schistosome antigens. Bone marrow-derived dendritic cells (BMDCs) from TLR2-deficient (TLR2(-/-)) or TLR4-deficient (TLR4(-/-)) mice were activated with soluble schistosomule antigen (SSA) or soluble egg antigen (SEA). TLR2 mRNA expression was significantly increased in B6 BMDCs following SEA stimulation. TLR2-deficient BMDCs showed enhanced MHCII expression following SSA and SEA stimulation. TLR2-deficient but not TLR4-deficient BMDC failed to produce IL-12p70 and IL-10 in response to schistosome antigens. TLR2-deficient BMDCs induced a stronger CD4(+) T cell proliferative response. IL-4 and IL-10 expression was inhibited in CD4(+) T cells primed with TLR2-deficient BMDCs, while enhanced in TLR4-deficient BMDCs-primed CD4(+) T cells. These results suggest that TLR2 is essential for the establishment of the DC production of IL-12p70 and IL-10.