CXCR4 and HIV-1 infection: In surprising contrast, not only did alkyl-CIMSS fail to inhibit HIV-1 infection, but it significantly increased both HIV-1BaL (R5-utilizing strain) and HIV-1IIIB (CXCR4-utilizing strain) infection of TZM-bl cells in a dose dependent manner relative to cells treated with DMSO control (Fig 1B and C).