Macroglobulin-Producing Plasma-Cell Tumor in Mice: Identification of a New Light Chain.

A transplantable plasmacell tumor in mice produces both a gammaM-macroglobulin serum protein with a sedimentation coefficient of 17S and a kappa-type urinary protein. The reduced and alkylated macroglobulin, when examined by electrophoresis in acid-urea polyacrylamide gel, had a fast component which migrated in the same position as the urinary protein and also a slow component. These two components, as shown by exclusion chromatography, represent the light and heavy polypeptide chains of the gammaM-macroglobulin. The aforementioned macroglobulin was antigenically related to that in normal mouse serum.