title: Control of J chain biosynthesis in relation to heavy and light chain synthesis, polymerization and secretion.
abstract: Mouse myeloma tumors and some variants derived from them were labeled in vitro with tritiated leucine and the radioactive J chain was assayed in cell lysates by precipitation with an antiserum specific for mouse J chain. The major findings were: 1) J chain can be found in an IgG2b-secreting cells (MPC-11). These data, together with previous findings suggest that cells secreting all classes of IgG synthesize J chain, even though there is no apparent requirement for J chain in assembly of the IgG molecule. Hence production of J chain does not depend upon secretion of a polymeric immunoglobulin. 2) Intracellular J chain can be found in myeloma variants that do not produce heavy chains showing that production of J chain may not coordinately be linked to the synthesis of heavy chain. 3) J chain was found in cells synthesizing, but not secreting, immunoglobulin. Thus production of J chain is not linked to secretion of immunoglobulin. 4) J chain could not be detected in plasma cells that do not produce immunoglobulins. It was also not found in mouse leukemic cells, suggesting that production of J chain is probably linked in some way to immunoglobulin production.
mesh_terms: D000818:Animals; D000917:Antibody Formation; D002460:Cell Line; D002478:Cells, Cultured; D006041:Goats / Q000276:immunology; D007106:Immune Sera; D007070:Immunoglobulin A / Q000096:biosynthesis; D007128:Immunoglobulin Fragments / Q000096:biosynthesis*; D007074:Immunoglobulin G / Q000096:biosynthesis; D007143:Immunoglobulin Heavy Chains / Q000096:biosynthesis*; D007144:Immunoglobulin J-Chains / Q000096:biosynthesis*; D007075:Immunoglobulin M; D007930:Leucine / Q000378:metabolism; D007942:Leukemia, Experimental / Q000276:immunology; D051379:Mice; D009101:Multiple Myeloma / Q000276:immunology; D011108:Polymers; D011233:Precipitin Tests; D011817:Rabbits / Q000276:immunology; D014316:Tritium
chemical_list: D007106:Immune Sera; D007070:Immunoglobulin A; D007128:Immunoglobulin Fragments; D007074:Immunoglobulin G; D007143:Immunoglobulin Heavy Chains; D007144:Immunoglobulin J-Chains; D007075:Immunoglobulin M; D011108:Polymers; D014316:Tritium; D007930:Leucine