TLR3 and TLR4 are not required for T. cruzi induction of ifnb. Relative ifnb transcript abundance was measured by qRT-PCR in WT, TLR3−/−, and TLR4−/− BMDM (A), WT and TLR2−/−/TLR4−/− MEF (B), or WT and TLR3−/− MEF (C) following infection with T. cruzi for 16 h (MEF) or 6 h (BMDM). D, HEK293 cells stably expressing TLR3 HEK293-tlr3 were infected with T. cruzi or activated with the TLR3 ligand poly(I:C) for 16 h and relative IFN-β mRNA levels were measured by qRT-PCR. Values reported represent the mean fold induction relative to mock-infected controls ± SD.