To address which CCR5 epitopes (and by extension, which CCR5 conformations) are primarily used for HIV-1 infection, we identified a high CCR5 expressing PBMC donor and infected the cells with HIV-1BaL for 1 week before staining and measuring CCR5 surface conformation frequency using the six mAbs previously used in the three cell line experiments. The gene discussed is CCR5; the disease is HIV-1 infection.