Levine M H, Haberman A M, Sant'Angelo D B, Hannum L G, Cancro M P, Janeway C A, Shlomchik M J
Section of Immunobiology, Department of Laboratory Medicine, and Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06520, USA.
Proc Natl Acad Sci U S A. 2000 Mar 14;97(6):2743-8. doi: 10.1073/pnas.050552997.
Seventy percent of peripheral immature conventional (B2) B cells fail to develop into mature B cells. The nature of this cell loss has not been characterized; the process that governs which immature B cells develop into long-lived peripheral B cells could be either stochastic or selective. Here, we demonstrate that this step is in fact selective, in that the fate of an immature B cell is highly dependent on its Ig receptor specificity. A significant skewing of the B cell receptor repertoire occurs by the time cells enter the mature B cell fraction, which indicates that there is selection of only a minority of immature B cells to become mature B cells. Because only a few heavy-light chain pairs are enhanced of the diverse available repertoire, we favor the idea that selection is positive for these few heavy-light chain pairs rather than negative against nearly all others. Because most immature B cells are lost at this transition, this putative positive selection event is likely to be a major force shaping the mature B cell receptor repertoire available for adaptive immune responses.
70%的外周未成熟常规（B2）B细胞无法发育为成熟B细胞。这种细胞损失的本质尚未明确；决定哪些未成熟B细胞发育为长寿外周B细胞的过程可能是随机的，也可能是选择性的。在此，我们证明这一步骤实际上是选择性的，因为未成熟B细胞的命运高度依赖于其免疫球蛋白受体特异性。当细胞进入成熟B细胞部分时，B细胞受体库会出现显著的偏差，这表明只有少数未成熟B细胞被选择成为成熟B细胞。由于在多样的可用库中只有少数重链-轻链对得到增强，我们倾向于这样一种观点，即选择对这少数重链-轻链对是正向的，而不是对几乎所有其他对是负向的。由于大多数未成熟B细胞在这个转变过程中丢失，这种假定的正向选择事件可能是塑造可用于适应性免疫反应的成熟B细胞受体库的主要力量。
