Cutting edge commentary: origins of B-1 cells.
The origin of B-1a cells, a minority population of B cells that express CD5, are abundant in coelomic cavities, and often produce autoantibodies, has been the subject of study for many years. Accumulating evidence demonstrates that the hypothesis that only B cells arising in fetal or neonatal tissues have the potential to become B-1a cells cannot be true. Rather, B cell receptor-mediated signaling initiated by ligation of autoantigen has now been shown to be required for induction of the B-1a phenotype. Furthermore, cells with a functional B-1a phenotype can be induced from adult precursors by appropriate Ag. At the same time, microenvironment-specific events may determine the likelihood that a given B cell, either adult or fetal derived, enters this pathway. CD5 expression and possibly localization to the peritoneum appear to provide some protection to autoreactive cells otherwise slated for elimination.
Wortis
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Department of Pathology, Tufts University School of Medicine and Program in Immunology, Sackler School of Graduate Biomedical Sciences, Boston MA 02111, USA. henry.wortis@tufts.edu
Berland
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D000818:Animals; D016175:B-Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology*; D019070:Cell Lineage / Q000235:genetics / Q000276:immunology; D016130:Immunophenotyping