We next analyzed the pathways by which Listeria induces IFN-b. Our previous study and the above results strongly suggested the critical involvement of TLR2 [25] . TLR2 signaling depends on Mal/TIRAP and MyD88 adaptor proteins. We had previously shown that MyD88 contributed to full IFN-b induction by Listeria [25] . We then compared IFN-b production by wild-type and mal/ tirap 2/2 macrophages infected with EGDe or DpgdA (Fig. 3A) . Surprisingly, production of IFN-b was not decreased in infected macrophages deficient in Mal/TIRAP, indicating that the normal TLR2 adaptor Mal/TIRAP was not required for Listeria-mediated induction of IFN-b.