TLR9 and HIV-1 infection: While stimulation through TLR2, TLR3, TLR4 or TLR5 had no or very limited effect on HIV-1 infection in human aggregate lymphocyte cultures [19], ex vivo HIV-1 infection of human lymphoid tissue was reduced upon TLR9 stimulation and augmented upon TLR5 stimulation with flagellin [20], underscoring the cell type-dependence of these effects.