NuTH/I MoAb (10 μg/ml) almost completely inhibited infection of NP-2/CD4/FPRL1 cells, as well as NP-2/CD4/CCR5 cells, with all HIV/SIV strains tested, i. e., GUN-7WT, HCM342, CBL23, and mndGB-1, suggesting that FPRL1 mediates infection of HIV/SIV as a coreceptor, i. e., in a CD4-dependent manner. Here, CD4 is linked to infection.