AMD3451 inhibited infection with clinical HIV-1 isolates or a variety of R5, R5/X4, and X4 strains of HIV-1 and HIV-2 at an IC50 ranging from 1.2 to 26.5 μM in various T cell lines, CCR5- or CXCR4-transfected cells, PBMCs, and monocytes/macrophages. (160). This evidence concerns the gene CXCR4 and infection.