TLR1 and viral infectious disease: Of specific importance, TLR2-TLR1 and TLR2-TLR6, which signal through TIRAP and MyD88, are expressed on the cell surface and are recruited to the phagosome to induce IFN-β expression in monocytes upon viral infection [3] However, it remains unknown whether the cellular localization of TLR2 is important for NF-κB activation induced by LTA and Pam3CSK4 in monocytes.