FIG. 1.
Scheme for the in vitro evaluation of interactions between measles virus and HIV-1. MV, Vero cell (VC) lysate, or media were added to HIV-1-infected cells and incubated for 96 h. Alternatively, PBMCs were incubated with MV or VC lysate for 24, 48, or 72 h, and supernatant fluids were collected and incubated with HIV-1-infected PBMCs for 96 h. The levels of p24 antigen were determined by enzyme immunoassay. For HIV-1 infection with CCR5-tropic HIV-1BaL, PBMCs were infected for 48 h in the presence of 10 U IL-2/ml. For CXCR4-tropic HIV-1IIIB, PBMCs were stimulated with 10 U IL-2/ml and 2 μg phytohemagglutinin/ml for 24 h before the addition of HIV-1. The medium was removed, and the cells were infected for 24 h in the presence of 10 U/ml of IL-2.