CD4 expression by nontransfected M4C8 cells and cells expressing the RNase P associated U5 EGS molecules following exposure to HIV-1 clades A, B, C, and F (moi = 0.01 and 0.05). At a moi of 0.01 and 0.05, there was a reduction in CD4 expression by nontransfected M4C8 and M4C8 expressing the U5 EGS (560D) antisense control following exposure to each clade of HIV-1. The percentage of CD4 expressing cells remained constant in cultures of M4C8 cells expressing the U5 EGS (560) molecule following exposure to each HIV-1 clade at a moi of 0.01. At the elevated moi, viral mediated cytopathology was delayed in CD4+ cells expressing RNase P-associated U5 EGS (560) molecules. □, M4C8; ▴, M4C8 + U5 EGS (560); ●, M4C8 + U5 EGS (560D).