A simple screening system for anti-HIV drugs: Syncytium formation assay using T-cell line tropic and macrophage tropic HIV env expressing cell lines - Establishment and validation

The first step in cellular entry of HIV involves binding of the viral envel ope glycoprotein complex (gp120/gp41) to specific receptor molecules on the target cells. The cell-cell fusion (syncytium formation) between env expre ssing cells and CD4+ cells mimics the viral infection of the host cells. To search for anti-HIV substances preventing this process, we constructed the recombinant cell lines, HeLa/CD4/Lac-Z -and HeLa/T-env/Tat for T-cell trop ic (HIV-1(NL4-3)) system, and HOS/CD4/CCR5/Lac-Z and HeLa/M-env/Tat for mac rophage tropic (HIV-1(SF162)) system. When each pair of cells were co-incub ated for 20 hours, the multinuclear giant cells (syncytia) were formed and beta -galactosidase was expressed. These systems are less biohazardous beca use no infectious virus particles are used. Their validity in screening for anti-HIV substances which inhibit syncytium formation was confirmed using various known HIV entry inhibitors.