Enhancement of HIV-1 infection in cells expressing TRIMCyp by cyclosporine. A, MDTF or D17 cells, expressing TRIMCyp or not (control cells), were infected with HIV-1GFP. The virus dose was adjusted so that 1% to 3% of cells would be infected in the absence of cyclosporine for each cell line, and the infections were done in the presence of various cyclosporine concentrations. The percentage of infected cells was determined 2 days later by flow cytometry. B, as above, except that CsA concentration was constant (6 μM) and cells were infected with multiple doses of HIV-1GFP.