The Toll-like receptors (TLRs) and retinoic-acid-inducible gene ... Figure 2: Signalling through TLR3, TLR7, TLR8 and TLR9 in response to endosomal nucleic acids of viral origin.

TLRs on the plasma membrane (TLR1, 2, 4 and 6) detect viral proteins, which are released in the extracellular environment, while endosomal TLRs (TLR3 and 7–9) recognize viral nucleic acids.

TLRs on the plasma membrane (TLR1, 2, 4 and 6) detect viral proteins, which are released in the extracellular environment, while endosomal TLRs (TLR3 and 7–9) recognize viral nucleic acids.