BAFF-R expression correlates with positive selection of immature B cells.
The interaction between BAFF and BAFF-R is crucial for the development of mature B cells. Here, we report that the expression of BAFF-R is first detectable on a fraction of mouse CD19(+) CD93(+) IgM(+) CD23(-) and human CD19(+) CD10(+) IgM(+) BM B cells. This BAFF-R(+) BM B-cell population shows higher levels of surface IgM expression and decreased RAG-2 transcripts than BAFF-R(-) immature B cells. When cultured, mouse BAFF-R(-), but not BAFF-R(+) immature B cells spontaneously undergo B-cell receptor editing. However, BAFF-R(+) immature B cells cultured in the presence of an anti-κ light chain antibody are induced to undergo receptor editing. This receptor editing correlates with down-modulation of surface BAFF-R expression and the up-regulation of RAG-2 at the RNA level. B-cell receptor (BCR) cross-linking on splenic T1 B cells results in down-modulation of the BAFF-R, and receptor editing and RAG-2 up-regulation in a minor fraction of B cells. BCR cross-linking on splenic T2/3 B cells results in partly down and partly up-modulation of BAFF-R expression and no evidence for receptor editing. Overall, our data indicate that BAFF-R expression is tightly regulated during B-cell development in mouse and human and its expression is correlated with positive selection.
Department of Biomedicine, University of Basel, Basel, Switzerland.
Roxane
R
Tussiwand
Melanie
M
Rauch
Lukas A
LA
Flück
Antonius G
AG
Rolink
D000818:Animals; D053264:B-Cell Activating Factor / Q000276:immunology; D053265:B-Cell Activation Factor Receptor / Q000096:biosynthesis / Q000276:immunology*; D002454:Cell Differentiation / Q000276:immunology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000276:immunology; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D009687:Nuclear Proteins / Q000235:genetics / Q000276:immunology; D054448:Precursor Cells, B-Lymphoid / Q000276:immunology*; D012313:RNA / Q000737:chemistry / Q000235:genetics; D017393:RNA Editing / Q000276:immunology; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012641:Selection, Genetic / Q000276:immunology; D013047:Specific Pathogen-Free Organisms
D053264:B-Cell Activating Factor; D053265:B-Cell Activation Factor Receptor; D004268:DNA-Binding Proteins; D007075:Immunoglobulin M; D009687:Nuclear Proteins; C499311:RAG2 protein, human; C499308:Rag2 protein, mouse; C435926:TNFRSF13C protein, human; C505719:TNFSF13B protein, human; C486662:Tnfrsf13c protein, mouse; C505720:Tnfsf13b protein, mouse; D012313:RNA