CCR5 is the major chemokine receptor linked to HIV-1 transmission and progression, and the most potent chemokine as a natural ligand is called MIP-1alpha, which is also induced by this same receptor.54 Regarding HIV-1 infection initiation mechanisms, the beginning of the adsorption phase involves the binding of virions to the surface of target cells. This evidence concerns the gene CCR5 and HIV-1 infection.