Serum Agglutinators of Erythrocytes Sensitized with Enzyme Digested Anti‐RH Antibodies¹

Abstract

Summary Four anti‐Rh antibodies were digested with 4 different proteolytic enzymes: pepsin, papain, ficin and bromelin. It was demonstrated that most human sera will agglutinate erythrocytes sensitized with these antibodies when they are ‘modified’ by the proteolytic enzymes. The agglutinators in human sera were shown to be specific for the ‘modification’ characteristic of the specific enzyme, although papain and ficin agglutinators cross react. Furthermore, only a minimal degree of digestion of the globulin molecule is necessary to reveal the hidden determinant. A study of certain individuals subject to the stress of renal transplantation, tuberculosis or rheumatoid arthritis, showed some fluctuation in agglutination titer but the events eliciting this change remain elusive.