Lymphoma models for B-cell activation and tolerance. II. Growth inhibition by anti-mu of WEHI-231 and the selection and properties of resistant mutants.
Regulation of the growth of murine B-cell lymphomas has been used as a model for tolerance induction. The inhibition by anti-immunoglobulin reagents of the growth of WEHI-231 and several variant clones has now been studied. The parental line is exquisitely sensitive to growth inhibition by heterologous or monoclonal anti-mu or anti-k reagents and ceases to incorporate thymidine within 24-48 hr of exposure to anti-immunoglobulin reagents. Growth inhibition is initially reversible, but prolonged exposure to anti-mu results in cell death. This inhibition is specific for immunoglobulin light and heavy chains since growth is not inhibited by antibodies directed at either class I or class II histocompatibility antigens. In order to study the mechanism of growth inhibition, we have mutagenized WEHI-231 with ethylmethane sulfonate and cloned the surviving colonies in the presence of anti-mu. Such variants, which have been repeatedly recloned, are able to grow normally in the presence of anti-mu up to 100 micrograms/ml. These "resistant" clones, while expressing amounts of surface IgM similar to that observed on WEHI-231, do not differ markedly in their ability to cap their immunoglobulin receptors compared to the parental line but appear to have lost class II antigens. Cell cycle analysis revealed that anti-mu causes a block in the transition of WEHI-231 from G1 to S phase. The relevance of these processes to models of B-cell tolerance induction are discussed.
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D002455:Cell Division; D002460:Cell Line; D004195:Disease Models, Animal; D007108:Immune Tolerance; D007148:Immunoglobulin mu-Chains / Q000276:immunology; D007152:Immunologic Capping; D007700:Kinetics; D008213:Lymphocyte Activation; D008223:Lymphoma / Q000235:genetics / Q000276:immunology*; D051379:Mice; D009154:Mutation
D000888:Antibodies, Anti-Idiotypic; D007148:Immunoglobulin mu-Chains