IMMUNOLOGICAL STUDIES OF AN ATYPICAL (MYELOMA) IMMUNOGLOBULIN

Abstract

An 8S myeloma component, isolated from serum of a patient with myelomatosis is described, which appears to have no antigenic determinants in common with human [alpha]-, [delta]-, [gamma]- or /x-polypeptide chains as revealed by immunoelectrophoresis and Ouchterlony gel diffusion analysis. The myeloma protein migrates in the fast [gamma]-region on electrophoresis at pH 8.6 and has an elution volume on Sephadex G-200 similar to that of 6.5 S IgA [immunoglobulin A]. The isolated myeloma component has an approximate molecular weight of 200,000 and a total carbohydrate content of 10.7%. Reduction with [beta]-mercaptoethanol and acid dissociation yields light polypeptide chains of Type L and a carbohydrate-rich component, in the ratio of 1:4. Antisera specific to determinants on the heavy chains of the myeloma protein showed no reaction with the immunoglobulins A, D, G or M. Instead unique determinants were found on the heavy polypeptide chains.