Multiple Antigenic Determinants on Macroglobulins. ∗

Abstract

Summary

When a rabbit antiserum to human macroglobulin was reacted with human sera by immunoelectrophoresis, several distinct macroglobulin precipitin lines were revealed. Internal to the major beta-2M line all sera showed a second, and some a third, line. A fourth macroglobulin line appeared opposite the serum source in most sera examined. The major macroglobulin line was forked at its anodal end in some sera. The major macroglobulin line had a single curvature when produced by the rabbit antiserum used in most of these experiments, but had a double curvature when produced by a horse antiserum. These findings could be due to multiple antigenic sites on macroglobulins of a single molecular species, or to antigenically distinct macroglobulin molecules.