title: Alteration of immunoglobulin phenotype in cell culture-adapted lines of two mouse plasmacytomas.
abstract: Murine plasmacytomas can be adapted to continuous in vitro culture by alternate passage between culture and animal. We have found that the kinetics of adaptation reflect a selection for the growth of variant plasmacytoma cells. The inclusion of an altered immunoglobulin phenotype in such variant cells could explain the Ig-producing variants that we observed in two of six transplantable lines of plasmacytomas that were adapted to culture. The first variant, an IgM-producing cell line (104-76), was adapted from a transplanted line of MOPC 104E that had stopped producing IgM with binding specificity for alpha1-3 Dextran. Unlike MOPC 104E, the IgM of 104-76 contains kappa- instead of lambda-light chains and probably contains an altered or different mu-heavy chain. A second variant (352-57) was found in an IgG2b-producing tumor (MOPC 352) which was induced in a BALB/c mouse strain (CB-6) that carried Ig genes of the C57BL/Ka allotype. This cell line apparently switched from producing IgG2b molecules of the C57BL allotype (H9) and of a known idiotype to IgG1 molecules of the BALB/c allotype (F19) without the idiotype marker. The propagation of a biclonal plasmacytoma from the time of original tumor induction does not appear as a likely explanation for these results. Rather, we seem to be dealing with plasmacytoma variants or with the possible induction of secondary tumors of host origin.
mesh_terms: D000818:Animals; D002460:Cell Line; D000939:Epitopes; D014644:Genetic Variation; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D007136:Immunoglobulins; D051379:Mice; D009374:Neoplasms, Experimental / Q000235:genetics / Q000276:immunology*; D010641:Phenotype; D010954:Plasmacytoma / Q000235:genetics / Q000276:immunology*
chemical_list: D000939:Epitopes; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D007136:Immunoglobulins