TLR7 and infection: SIVmac239 infection in old ChRM also induced strong expression of several PRRs, including TLR7, TLR8, RIG-I, MDA5, AIM2, IFI16, TMEM173, ZBP1 and LY96, which function as extracellular signaling sensors for dsRNA, ssRNA, dsDNA and lipopolysaccharides (LPS) generated by viral and microbial translocation.