ABSTRACT
Lectins are proteins present in abundant quantity in plants and animals. The term lectin was first introduced in 1954 by Boyd and Shapleigh (1) and widely used presently for the designation of a sugar-binding protein of a nonimmune origin that agglutinates cells or precipitates glycoconjugates. These proteins have the ability to select human red blood cells according to their blood group. However, a very few lectins are proven to be blood group specific, and the use of lectins in blood grouping has limited scope. The agglutinating property of lectins is not restricted to red blood cells but extends to other cells, such as lymphocytes and microbial tissue cells. In lymphocytes, lectins induce mitosis and stimulate the action of antigens. Lectins interact with oligosaccharides of cell or glycoprotein surfaces. Consequently, few oligo or monosaccharides are able to inhibit or even revert the interaction. Although lectins act by their carbohydrate binding sites, they may reinforce their interaction with cells or proteins by hydrophobic effects. Because of their binding specificity lectins may be grouped together with enzymes and antibodies. These properties have led to their widespread use for such purposes as the isolation and analysis of complex carbohydrates, cell separation, and studies of cell surface architecture (2).
