Inhibition of Human Immunodeficiency Virus‐1 Infection by Human Conglutinin‐like Protein: In vitro Studies

The lectin‐like protein analogous to bovine conglutinin was purified from human serum. The carbohydrate‐binding ability of conglutinin‐like protein was inhibited by D‐mannose, N‐acetylglucosamine and L‐fucose as well as by mannan‐containing oligosaccharides. By applying a lectin‐based ELISA system it was demonstrated that conglutinin‐like protein binds to human immunodeficiency virus‐1 (HIV‐1) glycoprotein 120 (gpl20) via its carbohydrate binding site. In vitro experiments with T‐lymphoblastoid CEM cells revealed that conglutinin‐like protein abolishes infection by HIV‐1; a 50% cytoprotective concentration of 23.9 μg/ml was measured. These findings demonstrate that human conglutinin‐like protein binds to HIV‐gp120 and inhibits, under the described in vitro conditions, CEM cell infection.