Antigen-driven B cell differentiation in vivo.
Antigen-driven B cell differentiation in vivo.
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DOI：
10.1084/jem.178.1.295
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发表时间：
1993-07-01
影响因子：
15.3
通讯作者：
Nossal, G J
中科院分区：
文献类型：
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作者：
McHeyzer-Williams, M G;McLean, M J;Lalor, P A;Nossal, G J
生发中心特异性抗体的分泌和体细胞突变记忆B细胞的发展是T细胞依赖的半抗原（4-羟基-3-硝基苯基）乙酰（NP）攻击的结果。利用六参数流式细胞术和单细胞分子分析，我们可以直接监测个体应答性（同型转换）抗原特异性B细胞的体细胞超突变程度。目前的研究一方面提供了抗体分泌区招募的直接定量评估，另一方面提供了生发中心通往记忆的途径。在挑战后的第一周内，两个隔室的细胞扩张呈指数级且独立。在第一周结束时，体细胞突变的第一个证据仅限于生发中心途径。此外，生发中心细胞表达的第三个高变区（CDR3）即使在未突变的情况下也比它们的抗体分泌区短得多，这表明在体内这两个途径的分叉处可能发生了二次选择事件。到第二周结束时，大多数突变克隆表达较短的CDR3和亲和增加突变，这是体细胞突变后进一步选择的证据。这些数据为在体细胞突变开始之前生发中心内的大量增殖以及随后选择大量突变克隆型进入记忆区提供了证据。
The secretion of specific antibodies and the development of somatically mutated memory B cells in germinal centers are consequences of T cell- dependent challenge with the hapten (4-hydroxy-3-nitrophenyl)acetyl (NP). Using six-parameter flow cytometry and single cell molecular analysis we can directly monitor the extent of somatic hypermutation in individual responsive (isotype switched) antigen-specific B cells. The current study provides a direct quantitative assessment of recruitment into the antibody-secreting compartment on the one hand, and the germinal center pathway to memory on the other. Cellular expansion in both compartments is exponential and independent during the first week after challenge. The first evidence of somatic mutation, towards the end of the first week, was restricted to the germinal center pathway. Furthermore, germinal center cells express a significantly shorter third hypervariable region (CDR3), even when unmutated, than their antibody-secreting counterparts, suggesting a secondary selection event may occur at the bifurcation of these two pathways in vivo. By the end of the second week, the majority of mutated clones express a shorter CDR3 and affinity-increasing mutations as evidence of further selection after somatic mutation. These data provide evidence for substantial proliferation within germinal centers before the initiation of somatic mutation and the subsequent selection of a significant frequency of mutated clonotypes into the memory compartment.