Effects of anti-IgM suppression on polyclonally activated murine B cells: analysis of immunoglobulin mRNA, gene specific nuclear factors and cell cycle distribution.
Polyclonal activation of murine B cells with bacterial lipopolysaccharide (LPS) and dextran sulfate (DxS) results in cell proliferation as well as increased immunoglobulin gene transcription and antibody secretion. When added to B cell cultures during mitogen activation, anti-mu antibody suppresses the rate of proliferation and immunoglobulin gene expression. Using this model system we show that co-cultures of B cells with LPS/DxS and anti-mu resulted in a decrease of both mu and kappa chain mRNA. Suppression did not prevent B cell entry into cycle nor a significant alteration in the distribution of cells in phases of cell cycle, although it did prolong the cycle transit time in a dose dependent fashion as determined by bromodeoxyuridine pulse labelling. Analysis of B cell specific nuclear binding factors, which previously have been shown to be important in regulating immunoglobulin gene transcription were examined. Results show that the kappa-specific enhancer binding activity of NF-kappa B was induced in activated as well as suppressed cultures. The lymphoid specific factor NF-A2, which recognizes the octamer sequence motif in the promoters of immunoglobulin genes, was induced by the polyclonal activation but was selectively lost in extracts from suppressed cells. Thus, specific regulation of the nuclear factor which plays a critical role in both heavy and light chain immunoglobulin gene expression may contribute to the transcriptional suppression observed in anti-mu treated B cells.
Marcuzzi
A
A
Institute of Human Genetics, University of Minnesota, Minneapolis 55455.
Van Ness
B
B
Rouse
T
T
Lafrenz
D
D
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D001402:B-Lymphocytes / Q000276:immunology*; D002453:Cell Cycle; D002455:Cell Division; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism; D016264:Dextran Sulfate; D003911:Dextrans / Q000494:pharmacology; D005434:Flow Cytometry; D007075:Immunoglobulin M / Q000276:immunology*; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D007148:Immunoglobulin mu-Chains / Q000235:genetics* / Q000276:immunology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D016328:NF-kappa B; D050813:Octamer Transcription Factor-2; D012333:RNA, Messenger / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism
D000906:Antibodies; D004268:DNA-Binding Proteins; D003911:Dextrans; D007075:Immunoglobulin M; D007145:Immunoglobulin kappa-Chains; D007148:Immunoglobulin mu-Chains; D008070:Lipopolysaccharides; D016328:NF-kappa B; D050813:Octamer Transcription Factor-2; C489206:Pou2f2 protein, mouse; D012333:RNA, Messenger; D014157:Transcription Factors; D016264:Dextran Sulfate