Lebecque S, de Bouteiller O, Arpin C, Banchereau J, Liu Y J
Schering-Plough, Laboratory for Immunological Research, Dardilly, France.
J Exp Med. 1997 Feb 3;185(3):563-71. doi: 10.1084/jem.185.3.563.
B lymphocytes undergo affinity maturation of their antigen receptors within germinal centers. These anatomical structures develop in secondary lymphoid organs from the clonal expansion of a few antigen-specific founder B cells, whose isolation and characterization are reported here. Human germinal center founder cells express the naive B cell markers surface IgM and IgD as well as the germinal center B cell markers CD10 and CD38. They express low levels of Bcl-2, high levels of Fas, and undergo rapid apoptosis in culture. The smaller nonproliferating sIgM+IgD+CD38+ B cells displayed a lower level of somatic mutation in their immunoglobulin variable region genes compared with the large proliferating ones. Unmutated sIgM+IgD-CD38+ tonsillar B cells may thus represent germinal center founder cells in which the program for apoptotic cell death is triggered before the onset of somatic mutation, allowing the selection of the germline antibody repertoire at an early stage.
B淋巴细胞在生发中心经历其抗原受体的亲和力成熟。这些解剖结构在二级淋巴器官中由少数抗原特异性起始B细胞的克隆扩增而形成，本文报道了这些细胞的分离和特性。人类生发中心起始细胞表达初始B细胞标志物表面IgM和IgD以及生发中心B细胞标志物CD10和CD38。它们表达低水平的Bcl-2、高水平的Fas，并在培养中经历快速凋亡。与大量增殖的细胞相比，较小的不增殖的sIgM+IgD+CD38+ B细胞在其免疫球蛋白可变区基因中显示出较低水平的体细胞突变。因此，未发生突变的sIgM+IgD-CD38+扁桃体B细胞可能代表生发中心起始细胞，其中凋亡性细胞死亡程序在体细胞突变开始之前就被触发，从而在早期阶段允许选择种系抗体库。
