Carbohydrate induced modulation of cell membrane. VI. Binding of exogenous lectin induces susceptibility of erythrocytes to free radical damage: a spin label study.

The oxidation of erythrocyte membrane has been widely used as a model to study the damage of biomembranes by free radicals. Whether binding of lectin to erythrocytes has any effect on peroxidant injury has never been studied. This study reports for the first time that crosslinking of erythrocyte surface glycoprotein by an exogenous lectin significantly enhances the susceptibility to membrane damage by free radicals, as evidenced by the increase in membrane fluidity measured by EPR using spin label and the increase in the amount of oxyhemoglobin liberated due to cell lysis.

Carbohydrate induced modulation of cell membrane VII. Binding of exogenous lectin increases osmofragility of erythrocytes.

Due to their multivalent binding character, lectins when added exogenously will cross-link membrane surface receptors leading to lateral molecular reorganizations in the plane of the bilayer. This study reports for the first time that agglutination of rabbit erythrocytes by lentil lectin and concanavalin A increases their osmofragility. Increase in osmofragility was detected by measuring the hemolysis of erythrocytes in hypotonic as well as in isotonic solutions. It was also found that agglutination per se does not increase osmofragility but the binding of legume lectin is essential since human Rh+ cells agglutinated by a monoclonal antibody do not exhibit hemolysis.