Effect of HHV-8 infection on HIV reactivation in chronically infected U1 monocytes. (A-B) U1 cells were infected with HHV-8 or transfected with plasmid pCR-50sp and analyzed for HIV reactivation by measuring p24 antigen release (A) and production of infectious particles in culture supernatant (B). (A) • indicates control; ▪, HHV-8 infection; ▴, TPA stimulation; and ♦, ORF 50 transfection. (C) HIV reactivation on contact with HHV-8-infected cells. U1 cells were cultured with HHV-8-infected or TPA-stimulated HUVECs or supernatant. HIV reactivation was analyzed by measuring the release in culture supernatants. Each value represents the mean of duplicate samples in 2 separate experiments. Error bars indicate SD.