Inhibition of HIV Infection by Lectin Binding to gp120

Human immunodeficiency virus (HIV) is the causative agent of AIDS (acquired immunodeficiency syndrome). The polypeptide precursor gp160 of HIV-1 forms the external glycoprotein, gp120 and the transmembrane glycoprotein, gp41 (1). Sequence variability is a feature of HIV viruses that have been classified into several subtypes (2). There are 22-31 potential N-linked glycosylation sites on gp120 depending on the HIV-1 isolate and thus, approximately half of its molecular weight is composed of carbohydrate. Gp120 oligosaccharides are a mixture of high mannose-, hybrid-, and complex-type N-glycans (3-5). The proportion of these N-glycan substituents on the envelope glycoprotein varies on different HIV-2 isolates propagated in different cell lines (6). The less-processed oligosaccharides are primarily located on conserved N-linked glycosylation sites on the recombinant gp120s produced in CHO cells and by a baculovirus expression system (4,7). This points to the high mannose and hybridtype oligosaccharides as being important in the structure and/or function of the envelope glycoprotein.