ObjectiveTo develop a useful system for evaluating novel anti-HIV drugs.DesignThe activity of most antiviral compounds in cell-free HIV infection systems has been evaluted. However, the inhibitory effects on both the process of HIV induction and viral dissemination to uninfected cells have not been fully investigated. We have therefore developed a new cocultivation system using chronically HIV-infected monocytes and CD4+ T-lymphocytes in the presence of tumor necrosis factor (TNF).MethodsWe designed a cocultivation system using flow cytometry with U1 cells and Molt-4 cells in the presence of TNF. The antiviral activities of several compounds in the cocultivation system and other assay systems were compared.ResultsOnly pradimicin A and glycyrrhizin showed strong inhibitory activity in the cocultivation system in the presence of TNF, whereas dextran sulfate, curdlan sulfate and N-acetylcysteine exhibited moderate or weak inhibitory activity in the system. 3'-azido-2', 3'-dideoxythymidine and 2', 3'-dideoxyadenosine were completely ineffective in the system.ConclusionThese results support the suggestion that our cocultivation system includes HIV induction in chronically infected monocytes, and the resulting cell-to-cell infection between HIV-infected monocytes and Molt-4 cells or Molt-4 cells and their HIV-converted counterparts. Our new cocultivation system may constitute a useful tool in the identification of novel anti-HIV compounds.