TLR1 and viral infectious disease: Similarly, TLR3 recognizes dsRNA and activates canonical NF-κB in TRIF-dependent way.50 TLR2 forms a heterodimer with either TLR1 or TLR6 and recognizes components of bacteria, mycoplasma, and viruses.51,52 TLR1/TLR2 and TLR6/TLR2 heterodimers activate canonical NF-κB in TIRAP- and MyD88-dependent ways.39,53 TLR7 and TLR9 are located in the ER membrane and exclusively expressed in pDCs (plasmacytoid DCs), which produce massive IFN-I during viral infection,54,55 they also induce activation of canonical NF-κB in MyD88-dependent manner after sensing ssRNA and CpG DNA, respectively.56,57