title: Dual isotype expressing B cells [kappa(+)/lambda(+)] arise during the ontogeny of B cells in the bone marrow of normal nontransgenic mice.
abstract: Central to the clonal selection theory is the tenet that a single B cell expresses a single receptor with a single specificity. Previously, based on our work in anti-phosphocholine transgenic mouse models, we suggested that B cells escaped clonal deletion by coexpression of more than one receptor on their cell surface. We argued that "receptor dilution" was necessary when: (i) the expressed immunoglobulin receptor is essential for immune protection against pathogens and (ii) this protective receptor is autoreactive and would be clonally deleted, leaving a hole in the B cell repertoire. Here, we demonstrate that dual isotype expressing B cells arise during the normal ontogeny of B cells in the bone marrow and populate both the spleen and peritoneal cavity of nontransgenic mice. Furthermore, single cell analysis of the expressed immunoglobulin light chains suggests that receptor editing may play a role in the generation of a significant fraction of dual isotype expressing B cells.
authors.affiliation: Laboratory of Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA. rezankal@grc.nia.nih.gov
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Rezanka
authors.forename: James J
authors.initials: JJ
authors.lastname: Kenny
authors.forename: Dan L
authors.initials: DL
authors.lastname: Longo
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D001483:Base Sequence; D007132:Immunoglobulin Isotypes / Q000235:genetics / Q000276:immunology; D007135:Immunoglobulin Variable Region / Q000235:genetics / Q000276:immunology; D007145:Immunoglobulin kappa-Chains / Q000235:genetics / Q000276:immunology*; D007146:Immunoglobulin lambda-Chains / Q000235:genetics / Q000276:immunology*; D018189:Immunomagnetic Separation; D016130:Immunophenotyping; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D007132:Immunoglobulin Isotypes; D007135:Immunoglobulin Variable Region; D007145:Immunoglobulin kappa-Chains; D007146:Immunoglobulin lambda-Chains