Role of TLR2 and dectin-1 in the host response to Penicillium marneffei (51.10)

Abstract Pathogen-associated molecular patterns (PAMP) are recognized by Toll-like receptors (TLR) and C-type lectin receptors including Dectin-1. In the current study, we examined the role of TLR2 and 4 and dectin-1, a β-glucan receptor, in the host response to Penicillium marneffei, an opportunistic fungal pathogen in AIDS patients. IL-12p40 production by bone marrow-derived dendritic cells (BMDCs) stimulated with yeast cells of this fungal pathogens was significantly reduced in TLR2KO and MyD88KO mice, but not in TLR4KO and C3H/HeJ mice, compared to that in control mice. Such production was significantly lower in dectin-1KO mice than wild-type mice. In further experiments, HEK293 cells transfected with TLR2 and/or dectin-1 genes were stimulated with P. marneffei for a NFκB promoter assay. Compared to the cells transfected with control vector, significantly higher activity of NFκB was detected in TLR2-transfectant, but this response was not further enhanced by co-transfection with dectin-1. Taken together, these results demonstrated that TLR2 and dectin-1 played an important role in the recognition of P. marneffei by BMDCs.