title: Cutting edge: B cell linker protein is dispensable for the allelic exclusion of immunoglobulin heavy chain locus but required for the persistence of CD5+ B cells.
abstract: The pre-B cell receptor (pre-BCR) and the BCR are required for B lymphopoiesis and for the allelic exclusion of Ig genes. Mice lacking B cell linker (BLNK) protein that is a component of the BCR signaling pathway have impaired B cell development. In this report, we show that allelic exclusion is intact in BLNK(-/-) mice harboring a V(H)12 transgene. This differs from mice lacking the tyrosine kinase Syk that is upstream of BLNK in BCR signaling and contrasts with mice lacking SLP-76 that is the equivalent adaptor molecule in TCR-signal transduction. We also show that, whereas most wild-type V(H)12-expressing B cells are CD5(+), the majority of the splenic V(H)12-expressing BLNK(-/-) B cells are CD5(-). A small population of V(H)12-expressing, BLNK(-/-) CD5(+) B cells is detectable in the peritoneal cavity of younger but not older mice. This suggests that BLNK deficiency affects not only the generation but also the persistence of B-1 cells.
authors.affiliation: Institute of Molecular and Cell Biology, Singapore, Republic of Singapore.
authors.forename: S
authors.initials: S
authors.lastname: Xu
authors.forename: S C
authors.initials: SC
authors.lastname: Wong
authors.forename: K P
authors.initials: KP
authors.lastname: Lam
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000483:Alleles; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D018956:CD5 Antigens / Q000096:biosynthesis*; D002352:Carrier Proteins / Q000235:genetics* / Q000502:physiology; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002470:Cell Survival / Q000235:genetics / Q000276:immunology; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007075:Immunoglobulin M / Q000235:genetics; D008213:Lymphocyte Activation / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D010750:Phosphoproteins / Q000172:deficiency / Q000235:genetics* / Q000502:physiology; D011947:Receptors, Antigen, B-Cell / Q000235:genetics; D019076:Transgenes / Q000276:immunology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C113939:B cell linker protein; D018956:CD5 Antigens; D002352:Carrier Proteins; D007143:Immunoglobulin Heavy Chains; D007075:Immunoglobulin M; D010750:Phosphoproteins; D011947:Receptors, Antigen, B-Cell