CXCR4 and HIV-1 infection: As expected, CXCL12 and AMD3100 specifically inhibited CXCR4-tropic HIV-1 infection, with IC50 values of 47.9 ± 8 nM and 5.3 ± 0.4 nM, respectively (Fig. 1b), while Maraviroc blocked CCR5-tropic HIV-1 infection [52–54].