The Function of Proteolytic Enzymes and Tannic Acid in Inducing Erythrocyte Agglutination

Abstract

Summary The pretreatment of erythrocytes with bromelin, a proteolytic enzyme, results in a 2-to 3-fold increase in globulin coating the erythrocyte surface. This increased number of globulin molecules is not responsible for the agglutination of saline suspended erythrocytes by incomplete antibody. The pretreatment of erythrocytes with tannic acid increased the number of γ-globulin molecules coating erythrocytes. This increased number of globulin molecules is not responsible for the agglutination of γ-globulin-coated erythrocytes by antiglobulin serum. Neither proteolytic enzymes nor tannic acid function in hemagglutination procedures by inducing the coating of erythrocytes with a globulin molecule. Rather, by surface changes, they permit a normally nonagglutinating reaction to result in agglutination. It is postulated that the incomplete antibody has a potentially bivalent nature. The function of enzymatic treatment in converting incomplete antibodies to complete acting substances might well be the removal of steric obstructions resulting from the disposition of antigen and incomplete antibody sites.