Dörner T, Brezinschek H P, Foster S J, Brezinschek R I, Farner N L, Lipsky P E
Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas 75235-8884, USA.
Eur J Immunol. 1998 Feb;28(2):657-68. doi: 10.1002/(SICI)1521-4141(199802)28:02<657::AID-IMMU657>3.0.CO;2-Z.
Somatic hypermutation and subsequent selection play a significant role in shaping the peripheral B cell repertoire. This repertoire is composed of CD5+ (5%) and CD5- B cells (95%) which are known to traffic through different lymphoid compartments. Previous studies have shown that V(H) gene usage by CD5+ and CD5- B cells is similar, although mutations are more frequent in the latter. However, the effect of mutation and subsequent selection on the expressed V(H) repertoire of CD5+ and CD5- B cells has not been delineated in detail. This study, therefore, analyzed the mutational pattern of individual IgM+/CD5+ and IgM+/CD5- B cells. In both populations, mutations can occur without heavy chain isotype switching. Despite the differences in mutational frequency, the patterns of mutation and subsequent selection were comparable in CD5+ and CD5- B cells. These results imply that although mutations are more frequent in CD5- B cells, the overall mechanisms governing somatic hypermutation and subsequent positive and negative selection are similar in CD5+ and CD5- B cells.
体细胞高频突变及随后的选择在外周B细胞库的形成中发挥着重要作用。该细胞库由CD5+(5%)和CD5-(95%)B细胞组成，已知它们通过不同的淋巴区室迁移。先前的研究表明，CD5+和CD5-B细胞的V(H)基因使用情况相似，尽管后者的突变更为频繁。然而，突变及随后的选择对CD5+和CD5-B细胞表达的V(H)细胞库的影响尚未得到详细描述。因此，本研究分析了单个IgM+/CD5+和IgM+/CD5-B细胞的突变模式。在这两个群体中，可以在没有重链同种型转换的情况下发生突变。尽管突变频率存在差异，但CD5+和CD5-B细胞的突变模式及随后的选择模式具有可比性。这些结果表明，尽管CD5-B细胞中的突变更为频繁，但在CD5+和CD5-B细胞中，控制体细胞高频突变及随后的阳性和阴性选择的总体机制是相似的。
