Effect of Acylase on the Agglutinability of Human Erythrocytes

Abstract

SEVERAL workers have reported the inactivation of human erythrocyte agglutinogens by enzymes^1–3. Acylase from hog kidney, able to hydrolyse 20,000 µmoles of acetyl D,L-methionine/mg of protein nitrogen/h, specifically diminished agglutinability of human group A erybhro-cytes. A 2 per cent suspension of the erythrocytes in an isotonic veronal buffer solution of pH 7.35 containing 0.25 per cent of the enzyme was incubated at 37° C for 3 h. The erythrocytes were washed three times in the same buffer solution, to remove the enzyme, and tested for agglutinability with serial dilutions of human anti-A sera. Controls, consisting of erythrocytes from the same individuals, treated with the same amount of veronal buffer solution instead of the enzyme solution, were simultaneously tested. Weak or negative agglutination was observed with the treated erythrocytes of group A (A₁, A₂ and also A₁B and A₂B) at the higher dilutions of anti-A sera. Erythrocytes of the groups B, O, M, N, D, C, E, c and e did not show any alteration in agglutinability caused by a similar enzyme treatment.