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 (gp120) 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 micrograms/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.