Wang Hongsheng, Clarke Stephen H
Deptartment of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
Immunol Rev. 2004 Feb;197:51-9. doi: 10.1111/j.0105-2896.2004.0098.x.
B cells of varying antigen specificities are consistently present in the unmanipulated repertoire. These B cells appear to belong to the marginal zone (MZ) and B1 B-cell subsets and provide protection to the blood and lymph, respectively. Some are specific for self-antigens, suggesting that they are selected based on specificity for self but have a protective role against foreign pathogens. One of these specificities is for phosphatidylcholine (PtC). Anti-PtC B cells comprise 5-8% of the B1 repertoire and are protective against bacterial pathogens. In general, they are restricted to the expression of two VH/Vkappa combinations, VH11/Vkappa9 and VH12/Vkappa4/5H. This review focuses on the differentiation of VH12 anti-PtC B cells. They undergo a series of positive selection events beginning at the pre-B-cell stage that enriches for those with a VHCDR3 and L chain required for PtC binding and eliminating the majority of VH12 B cells that lack the ability to bind PtC. Thus, positive selection focuses the VH12 repertoire toward PtC, ensuring that anti-PtC VH12 B cells are a significant component of the B1-cell repertoire in all individuals.
具有不同抗原特异性的B细胞持续存在于未受操控的库中。这些B细胞似乎属于边缘区（MZ）和B1 B细胞亚群，分别为血液和淋巴提供保护。有些对自身抗原有特异性，这表明它们是基于对自身的特异性被选择的，但对抵御外来病原体具有保护作用。其中一种特异性是针对磷脂酰胆碱（PtC）。抗PtC B细胞占B1库的5-8%，对细菌病原体具有保护作用。一般来说，它们局限于两种VH/Vκ组合的表达，即VH11/Vκ9和VH12/Vκ4/5H。本综述聚焦于VH12抗PtC B细胞的分化。它们在pre-B细胞阶段开始经历一系列阳性选择事件，富集那些具有PtC结合所需VHCDR3和轻链的细胞，并消除大多数缺乏PtC结合能力的VH12 B细胞。因此，阳性选择使VH12库朝向PtC聚焦，确保抗PtC VH12 B细胞是所有个体B1细胞库的重要组成部分。
