The Effect of Ficin on the Agglutination of Human Red Blood Cells

Abstract

A concentration of 1.5 mg of ficin per ml of packed cells, a pH range from 4.7 to 7.8, an incubation temperature of 22° to 37°C and an incubation period of 10 to 30 minutes were found to be the optimum conditions for making A, B and Rh-positive cells agglutinable by the homologous “complete” and “incomplete” antibodies. Ficin was found to be more efficient than trypsin and papain for increasing the sensitivity of O Rh-positive, A and B cells in hemagglutination. The intracellular protease activator, L-cysteine-HCl, accelerated significantly the rate of sensitization of O Rh-positive cells by papain, but not by ficin.