Synthesis but not Secretion of J Chain by Variant Mouse Myeloma Cells Which Lose α-Chain-Synthesizing Ability

Open Access
Publisher Website
Google Scholar
Abstract
We have devised a rapid method for obtaining large amounts of J chain from IgA in the ascitic fluid of mice bearing the MOPC 315 tumor. The J chain was released by reduction from the MOPC 315 IgA adsorbed onto a DNP-lysyl-Sepharose column, and was further purified by DEAE Sephadex chromatography. The mouse J chain was characterized as to its electrophoretic mobility, amino acid composition, apparent size, presence in different immunoglobulin classes, and reactivity with an antiserum containing anti-J chain activity. Variant cell lines have been selected from the IgA-producing mouse myeloma cell line MOPC 315. The variants did not synthesize detectable quantities of α heavy chains but continued to synthesize and secrete light chains. J chain was synthesized by both parent and variant cell lines but only secreted by the parent cells. It is postulated that J chain synthesis is not dependent on α heavy chain synthesis, but that secretion of J chain by MOPC 315 cells occurs only because of its attachment to the IgA molecule.

This publication has 0 references indexed in Scilit: