The stages of B cell development and VDJ recombination
• 3 main stages (orange): no immunoglobulin chains (pro-B cell), heavy chain only (Pre-B cell), both heavy and light chain (immature and mature B cells)
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•Heavy chain first (DJ then VDJ)è Large pre-B cell (Pre-B cell receptor)è halt heavy chain rearrangement, “surrogate” light chain pairs with heavy chain èpre-B receptor è cells divide è cease dividingè Small resting pre-B cellè RAG start to rearrange light chainè Immature B cell with IgM on surfaceè selection of self-toleranceè peripheral lymphoid tissueè Mature B cell with addition of mIgDè ready for ligation and activation by the appropriate foreign Ag