Enzymes from Human Gastric Mucosa Conferring Blood‐Group A and B Specificities upon Erythrocytes

Abstract

Enzyme preparations obtained from human gastric mucosa microsomes are able to provide human erythrocytes with blood‐group A and B specificities, the newly conferred serological properties being dependent on the blood‐group of the tissue donor. The time‐course and the extent of the enzyme‐catalyzed change in antigenic properties of the erythrocytes were assessed by the serum absorption method. The enzyme preparation from gastric mucosa of group A 1 individuals, when incubated with O or B erythrocytes in the presence of UDP‐acetylgalactosamine, rendered them agglutin‐able by anti‐A serum. The enzymatically converted erythrocytes behaved like A 2 cells. After treatment with enzyme from B individuals and UDP‐galactose, O, A 1 and A 2 erythrocytes could be agglutinated by anti‐B serum. When the enzymes from A 1 and B individuals were allowed to act together upon O erythrocytes in the presence of UDP‐acetylgalactosamine and UDP‐galactose, the red cells became susceptible to agglutination with both anti‐A and anti‐B serum. The blood‐group specificity of red cells was not changed upon exposure to microsomal extracts from O individuals.