TLR2 and infection: Since we showed that TLR13 was the only endosomal TLR capable of sensing S. pyogenes (Fig. 1), the results obtained using TLR2 and Unc93b1 double-deficient cells further strengthened the exclusive roles of TLR2 and TLR13 in responses to S. pyogenes. Finally, antibody-mediated blocking of TLR2 in TLR13-deficient cells resulted in strong reduction of cytokine production 4 h after infection, at the time of predominantly TLR2-mediated cell surface-localized S. pyogenes recognition (Fig. 2K-M).