SULPHOEVERNAN, A POLYANIONIC POLYSACCHARIDE, AND THE NARCISSUS LECTIN POTENTLY INHIBIT HUMAN-IMMUNODEFICIENCY-VIRUS INFECTION BY BINDING TO VIRAL ENVELOPE PROTEIN

Sulphoevernan is a sulphated α-1 ← 3,1 ← 4 polyglucan (M(r) 20000) with a helical structure. This compound effectively inhibits both human immunodeficiency virus type 1 (HIV-1) and type 2 infection of cells in vitro at concentrations around 0.5 μg/ml. Moreover, the compound completely inhibits HIV-1-induced syncytium formation at a concentration of 1 μg/ml. Competition experiments with 35S-labelled sulphoevernan revealed that the mannose-specific lectin from narcissus pseudonarcissus prevented binding of sulphoevernan to HIV-1, whereas the antibody OKT4A did not reduce the amount of sulphoevernan bound to MT-2 cells. These data indicate that the non-cytotoxic polymer sulphoevernan binds to the virus rather than to the host cell. In vivo studies, using Rauscher leukaemia virus in NMRI mice, revealed that, at a daily dose of 20 mg/kg, the animals were protected against virus-induced increases in spleen weight. From these in vitro and in vivo data we conclude that sulphoevernan has potential in the treatment of acquired immunodeficiency syndrome.