NATURALLY OCCURRING HUMAN ANTIBODY REACTING WITH BENCE JONES PROTEINS

Abstract

Agglutinating substances having characteristics of naturally occurring macroglobulin antibodies to human Bence Jones proteins have been identified in human sera. By means of hem-agglutination and hemagglutination inhibition techniques, common determinants have been demonstrated on the light (L) polypeptide chains of pooled normal human [gamma]2-globulin and on some Bence Jones proteins of group 1 but not of group 2. Individual human sera serve to delineate subgroups of the two major antigenic groups of the Bence Jones proteins by agglutinating cells coated by one but not another protein of the same antigenic group. The capacity of the L polypeptide chains and proteolytic fragments of [gamma] 2 -globulin to inhibit the hemagglutination reaction between Bence Jones protein or L chain-coated cells and human sera was examined. The determinants, toward which agglutinators of human serum are directed, appear to be blocked in intact [gamma] 2-globulin and in all fragments in which H chain remains in proximity to L chain. It would appear that the presence of H chains bound to L chains by non-covalent bonds completely obstructs the reactivity of the involved L chain groups.