[Biological importance of the reactions between lectins and glycoconjugates in man]

Glucidic structures are now widely shown to be responsible of many recognition phenomenons. The biological efficiency of cellular membrane associated receptors depends on their stereospecific interactions with ligands. Glucidic structures are implicated in the interactions occurring between lectins and glycoconjugates. Although the knowledge about human lectins is still limited, such activities are now widely obvious for several cells: --erythrocytes: hemagglutin activity of glycophorin; --lymphocytes: Ts and NK cells; --platelets: plasma membrane and cell secreted lectins; --hepatic cells: lectins of hepatocytes and Kupffer cells; --muscular cells: galactose and heparin inhibitable lectins; --cells of human glomerular basement membrane: N-acetylosamines and N-acetyl neuraminic acid inhibitable lectins. To this list may be added the cytoagglutinating activity of fibronectin involved in cell-cell, cell-molecule or molecule-molecule interactions. The importance of lectinic agglutinins may be emphasized for several fundamental physiological mechanisms involved in molecular and cellular recognition: defenses against infection, coagulation, aging.