Hybridomas derived from lipopolysaccharide-activated anti-mu-treated B cells have active suppression of IgM secretion, demonstrable by secondary fusion.
Treatment of LPS-stimulated mouse B cells with bivalent anti-mu antibodies suppresses differentiation to Ig-secreting cells without interfering with proliferation. This treatment selectively inhibits up-regulation of transcription of differentiation-related genes. Induction of anti-mu suppression requires RNA and protein synthesis, suggesting involvement of a transcriptional repressor. We describe experiments designed to capture the repressed phenotype of anti-mu-treated cells. Fusions of anti-mu-treated cells with the B lymphoma line M12.4.5, but not plasmacytoma Ag8.653, yielded a significantly lower frequency of secretory hybridomas than did parallel fusion of cells treated with LPS only. To test for active repression, nonsecreting cloned hybridomas were secondarily fused to LPS-activated normal B cells. Secondary hybridomas with anti-mu parentage had a very low frequency of IgM secretion. Active suppression could only be demonstrated by secondary fusion. Neither supernatants nor extracts of repressor hybridomas influenced LPS-driven differentiation of normal B cells. These results confirm that this form of differentiation suppression is an active process, probably mediated by transcriptional controls. Repressor hybridomas should prove useful for studies of molecular mechanisms.
Lawton
A R
AR
Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232.
Summerlin
V S
VS
Dooley
J S
JS
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D002459:Cell Fusion; D006825:Hybridomas / Q000502:physiology*; D007075:Immunoglobulin M / Q000276:immunology / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D012097:Repressor Proteins / Q000502:physiology*; D014158:Transcription, Genetic
D000888:Antibodies, Anti-Idiotypic; D007075:Immunoglobulin M; D008070:Lipopolysaccharides; D012097:Repressor Proteins