PTPRC and colitis: In our hands, TLR 9 was expressed predominantly by the subset of LP DC with the PDCA-1+B220+ phenotype of plasmacytoid DC, as has been reported in other tissues 11, Others have recently shown a small population of plasmacytoid DC in mouse LP 33 and the potential importance of these cells is demonstrated by the fact that TLR 9 is needed for protective immunity during small intestinal toxoplasmosis in mice 32 and to protect mice from DSS-induced colitis 34.