Effect of HHV-8 infection on HIV in monocytes. U937 cells were infected with HHV-8 or transfected with plasmid pCR-50sp and subsequently infected with HIV_IIIB at a 1:1000 MOI. Control cells were cultured in the absence of TPA, or mock-infected with UV-inactivated virus, or transfected with the empty pCR vector; the results obtained were identical, and the values shown represent the mean of the 3 controls. p24 antigen release (A) and HIV virion production (B) were evaluated. Values represent the mean of duplicate samples of 2 separate experiments. Error bars indicate SD. (C) The results are shown of rtPCR amplification of HIV gag gene using 200 ng total RNA extracted from infected cells; β-actin amplification is shown as a control. Control for DNA contamination, performed by direct β-actin amplification of RNA without retrotranscription, is also shown.