The Galactose-Specific Lectin from the Sponge Chondrilla Nucula Displays Anti-Human Immunodeficiency Virus Activity in vitro via Stimulation of the (2′-5′)Oligoadenylate Metabolism

Abstract

A new lectin has been isolated from the sponge Chondrilla nucula. The purified CN lectin is a protein composed of four polypeptide chains with a molecular weight (MW) of 15600. The isoelectric point is 4.5 and the amino acid composition is rich in aspartic and glutamic acid. The lectin precipitates erythrocytes from humans (A, B, O) with a titre between 2⁵ and 2¹⁰. The CN lectin is d-galactose-specific and displays a moderate mitogenic effect on spleen lymphocytes from mice and on CD4-positive human H9 cells. An interesting feature of this lectin is its ability to stimulate the (2′-5′)oligoriboadenylate [(2′-5′)A] metabolic pathway in non-infected and human immunodeficiency virus (HIV-1)-infected H9 cells. Moreover, HIV-1-infected H9 cells show an increase in the time period of HIV-1 release in response to CN lectin treatment. These data suggest that CN lectin causes a retardation of HIV-1 release due to further increase of the elevated intracellular level of (2′-5′)A.