CCR5 and infection: Similarly, the transduced cells were inoculated with three CXCR4-tropic (NL4-3, SG3.1, and LAI.2) and three CCR5-tropic (RHPA.c/2635, TRJO.c/2851, and MJ4) viruses, and infections were monitored over time by detecting intracellular HIV-1 p24 antigen and GFP expression.