Consistent with our previous report measuring secretion of IFNb protein in PEM, IFN-b mRNA synthesis induced by L. monocytogenes infection of PEM required TLR2 ( Fig. 2A) , while TLR2-deficient BMM showed no impairment in their synthesis of IFN-b mRNA (Fig. 2B) . Moreover, IFN-b secretion was strongly reduced in tlr2 2/2 PEM infected with both the DpgdA mutant ( Fig. 2C ) and the complemented DpgdA strain (Fig. 2D) , definitively establishing the TLR2 dependence of IFN-b production.