IMMUNOLOGIC RELATION OF STREPTOCOCCAL AND TISSUE ANTIGENS

Abstract
Sera from patients with recent streptococcal infection or non-suppurative sequelae exhibit with variable frequency a precipitin reaction in agar gel with a partially purified streptococcal antigen which has been shown previously to be immunologically related to human heart tissue. This precipitin could be absorbed from sera with normal human heart tissue homogenates but not with homogenates of other organs. Demonstration of this cross-reaction by heart absorption was found dependent both upon the serologic properties of individual sera and the nature or state of purification of the streptococcal product employed as test antigen. Evidence was obtained of a close association of heart-related and non-heart-related antigenic determinants in partially purified preparations of the streptococcal antigen by both gel diffusion and immunoelectrophoresis. On immunoelectrophoretic analysis, cross-reactive antigen exhibited a more rapid mobility toward the anode than M protein. It was destroyed by digestion with trypsin, pepsin, and chymotrypsin. Based on specific absorption tests with a Type 5 and Type 19 strain, the antigen was localized to cell walls and to a lesser extent to cell membranes of these strains.