LPS-nonresponsive variants of mouse B cell lymphoma, 70Z/3: isolation and characterization.
We have used a genetic approach to study the differentiation of B lymphocytes. The cultured murine cell line 70Z/3 resembles pre-B cells in containing the heavy chain of the immunoglobulin IgM, mu, as an internal protein in the absence of light chain, L. However, overnight incubation with the B cell mitogen lipopolysaccharide (LPS) induces the cells to mature to a B lymphocyte-like state by the induction of L chain synthesis and the appearance of IgM on the cell surface. We have used immunoselection against surface-bound IgM to isolate LPS uninducible variants of 70Z/3. These fall into two complementation groups, LPS A and LPS B. LPS A variants predominated and were found at a frequency of 1/1200. These cells were completely unresponsive to LPS. LPS B was represented by a single variant in which a subset of cells was induced to display wild-type levels of membrane-bound IgM, and the proportion of induced cells increased with prolonged incubation with LPS. We detected no structural defects in either variant group, but LPS B may represent a defect in the decision to differentiate in response to LPS.
D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002454:Cell Differentiation; D002460:Cell Line; D004247:DNA / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D005434:Flow Cytometry; D005816:Genetic Complementation Test; D006822:Hybrid Cells; D007075:Immunoglobulin M / Q000235:genetics*; D007148:Immunoglobulin mu-Chains / Q000235:genetics; D007942:Leukemia, Experimental / Q000235:genetics* / Q000276:immunology; D008070:Lipopolysaccharides / Q000235:genetics / Q000276:immunology*; D008223:Lymphoma / Q000235:genetics* / Q000276:immunology; D051379:Mice; D009154:Mutation
D007075:Immunoglobulin M; D007148:Immunoglobulin mu-Chains; D008070:Lipopolysaccharides; D004247:DNA