title: Evidence for a ligand-mediated positive selection signal in differentiation to a mature B cell.
abstract: Positive selection is required for B cell differentiation, as indicated by the requirement for expression of the pre-B cell receptor (pre-BCR) and the BCR at the pre-B and immature B cell stages, respectively. Positive selection mediated by a tonic signal from these receptors is sufficient to drive B cell differentiation beyond the pre-B and immature B cell stages, but it is unclear whether additional positive selection signals are required for differentiation to a mature B-2 cell. We have identified a population of Ig transgenic B cells that differentiatively arrest at a transitional B cell stage in the spleen. They exhibit no evidence of Ag encounter or negative selection and can differentiate to mature B-2 cells in vivo upon weak BCR stimulation or adoptive transfer to irradiated hosts. These data are consistent with a requirement for a ligand-mediated BCR signal for differentiation to a mature B-2 cell.
authors.affiliation: Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA.
authors.forename: Hongsheng
authors.initials: H
authors.lastname: Wang
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Clarke
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000276:immunology; D016175:B-Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology / Q000378:metabolism*; D001665:Binding Sites / Q000235:genetics / Q000276:immunology; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002470:Cell Survival / Q000235:genetics / Q000276:immunology; D018985:Epitopes, B-Lymphocyte / Q000378:metabolism; D015328:Gene Rearrangement, B-Lymphocyte, Light Chain / Q000235:genetics; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D007144:Immunoglobulin J-Chains / Q000235:genetics; D007135:Immunoglobulin Variable Region / Q000235:genetics; D007145:Immunoglobulin kappa-Chains / Q000235:genetics; D008024:Ligands; D008562:Membrane Glycoproteins / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D010713:Phosphatidylcholines / Q000378:metabolism; D054420:Pre-B Cell Receptors; D011947:Receptors, Antigen, B-Cell / Q000502:physiology; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000378:metabolism
chemical_list: D018985:Epitopes, B-Lymphocyte; D007143:Immunoglobulin Heavy Chains; D007144:Immunoglobulin J-Chains; D007135:Immunoglobulin Variable Region; D007145:Immunoglobulin kappa-Chains; D008024:Ligands; D008562:Membrane Glycoproteins; D010713:Phosphatidylcholines; D054420:Pre-B Cell Receptors; D011947:Receptors, Antigen, B-Cell