The first step in cellular entry of HIV involves binding of the viral envelope glycoprotein complex (gp120/gp41) to specific receptor molecules on the target cells. The cell-cell fusion (syncytium formation) between env expressing 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 tropic (HIV-1NL4-3) system, and HOS/CD4/CCR5/Lac-Z and HeLa/M-env/Tat for macrophage tropic (HIV-1SF162) system. When each pair of cells were co-incubated for 20 hours, the multinuclear giant cells (syncytia) were formed and β-galactosidase was expressed. These systems are less biohazardous because 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.
Japan Antibiotics Research Association