Antigenic analysis of uninfected or HIV-1–infected UT-7/fus cells. Cells were analyzed for the presence of CD41a, glycophorin A, and CD31 antigens. In each panel, slopes from uninfected and HIV-1–infected UT-7/fus cells are compared. The mean fluorescence intensity of both uninfected and HIV-1–infected UT-7/fus cells labeled with unspecific mouse IgG was always less than 5. In addition, on the top, the dot plots of each cell population are shown. The uninfected and HIV-1–infected UT-7/fus cell populations analyzed are, respectively, included in R1 and R2 areas.