Inhibitory effect of liposomes containing sulfatide or cholesterol sulfate on syncytium formation induced by bovine immunodeficiency virus-infected cells

The effect of galactocerebroside 3'-sulfate (sulfatide) or cholesterol sulfate on syncytium formation induced by bovine immunodeficiency virus (BIV)-infected cells was investigated in vitro. Sulfatide was purified from bovine brain and incorporated in liposomes which were composed of egg phosphatidylcholine (PC), cholesterol (Chol), and dipalmitoylphosphatidic acid (DPPA). Either sulfatide- or cholesterol sulfate-containing liposomes effectively prevented syncytium formation induced by BIV-infected cells, but the inhibitory effect of sulfatide alone on syncytium formation was low. On the other hand, neither liposomes containing galactocerebroside nor liposomes composed of egg PC, Chol, and DPPA had any effect on syncytium formation induced by BIV-infected cells. These results suggest that liposomes containing sulfatide or cholesterol sulfate are an efficient agent to inhibit syncytium formation induced by BIV-infected cells, and that sulfate residue might play an important role in the inhibition of syncytium formation.