Interestingly, a recent study suggested a role for an unidentified, novel mechanism in TLR3-, TLR4- and TLR7-mediated reduction of HIV-1 infection in primary macrophages [24], and a TLR3 polymorphism has just been shown to have a higher frequency among HIV-1-exposed seronegative individuals, and to confer some degree of natural resistance to HIV-1 infection [25]. Here, TLR4 is linked to HIV-1 infection.