Facultative role of germinal centers and T cells in the somatic diversification of IgVH genes.
Facultative role of germinal centers and T cells in the somatic diversification of IgVH genes.
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DOI：
10.1084/jem.181.4.1319
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发表时间：
1995-04-01
影响因子：
15.3
通讯作者：
Cerny, Jan
中科院分区：
文献类型：
--
作者：
Miller, Carla;Stedra, Jaroslav;Kelsoe, Garnett;Cerny, Jan
记忆B细胞的发育发生在淋巴滤泡的生发中心（GC），在那里抗原驱动的淋巴细胞经历体细胞超变和亲和选择，推测是在辅助T细胞的影响下。然而，驱动这种复杂反应的机制还不清楚。我们探讨了GC的形成和超突变的发病之间的关系，在响应半抗原磷酸胆碱（PC）耦合到抗原蛋白在小鼠轴承不同频率的CD 4 + T细胞。通过用花生凝集素（PNA）和抗AB 1 -2（T15+抗PC抗体的显性独特位）的单克隆抗体染色冷冻脾切片来鉴定PC反应性GC。重排的T15 VH 1基因的核苷酸序列测定从微切割的GC B细胞的基因组DNA的聚合酶链反应扩增。用PC-钥孔血蓝蛋白（KLH）或PC-鸡丙种球蛋白（CGG）初次免疫正常胸腺小鼠后，T15+ GC在第6- 7天完全发育。然而，晚至第10-14天从原发性GC中回收的VH 1基因片段具有低数量的突变，与半抗原硝基苯基或恶唑酮的反应相反，这些半抗原在GC形成后维持高水平的超突变。PC反应性B细胞在组织学典型的GC中增殖相当长的时间，没有或很少有体细胞超变; GC形成的信号独立于超变激活的信号。然后，我们在正常胸腺小鼠、在引发前用有限数量的正常CD 4+细胞重建的nu/nu小鼠（CD 4（+）-nu/nu）和nu/nu小鼠中检测了用PC-KLH二次免疫后7天的GC。所有这些动物在抗原引发后均发生T15+ GC，然而，继发性GC中V基因突变的模式反映了初次应答期间存在的CD 4+细胞水平。来自正常胸腺小鼠的次级GC的VDJ序列严重突变，但这些突变中的大多数在所有相关（相同的VDJ关节）序列之间共享，这表明突变的记忆B细胞增殖，几乎没有从头体细胞超突变。相反，CD 4（+）-nu/nu小鼠继发性GC中V基因多样性的模式表明，在再激发后的第一周内存在持续的突变和克隆多样化。来自T细胞缺陷型nu/nu小鼠的继发性GC显示T15+ B细胞突变和/或重组多样性的证据很少。我们的结论是，参与的CD 4+辅助细胞所需的完全激活的变构在GC和发生在剂量依赖性的方式。
The development of memory B cells takes place in germinal centers (GC) of lymphoid follicles where antigen-driven lymphocytes undergo somatic hypermutation and affinity selection, presumably under the influence of helper T cells. However, the mechanisms that drive this complex response are not well understood. We explored the relationship between GC formation and the onset of hypermutation in response to the hapten phosphorylcholine (PC) coupled to antigenic proteins in mice bearing different frequencies of CD4+ T cells. PC-reactive GC were identified by staining frozen splenic sections with peanut agglutinin (PNA) and with monoclonal Abs against AB1-2, a dominant idiotope of T15+ anti-PC antibody. The nucleotide sequences of rearranged T15 VH1 genes were determined from polymerase chain reaction amplifications of genomic DNA from microdissected GC B cells. T15+ GC became fully developed by day 6- 7 after primary immunization of euthymic mice with either PC-keyhole limpet hemocyanin (KLH) or PC-chicken gamma globulin (CGG). Yet the VH1 gene segments recovered from the primary GC as late as day 10-14 had low numbers of mutations, in contrast to responses to the haptens nitrophenyl or oxazolone that sustain high levels of hypermutation after GC formation. PC-reactive B cells proliferate in histologically typical GC for considerable periods with no or little somatic hypermutation; the signals for GC formation are independent of those for the activation of hypermutation. We then examined GC 7 d after secondary immunization with PC-KLH in euthymic mice, in nu/nu mice reconstituted with limited numbers of normal CD4+ cells before priming (CD4(+)-nu/nu) and in nu/nu mice. All of these animals develop T15+ GC after antigen priming, however, the patterns of V gene mutations in the secondary GC reflected the levels of CD4+ cells present during the primary response. VDJ sequences from secondary GC of euthymic mice were heavily mutated, but most of these mutations were shared among all related (identical VDJ joints) sequences suggesting the proliferation of mutated, memory B cells, with little de novo somatic hypermutation. In contrast, the patterns of V gene diversity in secondary GC from CD4(+)-nu/nu mice suggested that there was ongoing mutation and clonal diversification during the first week after rechallenge. The secondary GC from T cell-deficient, nu/nu mice showed little evidence for mutational and/or recombinational diversity of T15+ B cells. We conclude that the participation of CD4+ helper cells is required for full activation of the mutator in GC and takes place in a dose- dependent fashion.
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影响因子：
15.3
作者：
LEVY, NS;MALIPIERO, UV;GEARHART, PJ
通讯作者：
GEARHART, PJ
影响因子：
64.5
作者：
BEREK, C;BERGER, A;APEL, M
通讯作者：
APEL, M
影响因子：
5.4
作者：
LINTON, PJ;LO, D;KLINMAN, NR
通讯作者：
KLINMAN, NR
对（4-羟基-3-硝基苯基）乙酰基的初级免疫反应的原位研究。二.动脉周围淋巴鞘相关病灶和生发中心的常见克隆起源。
DOI：
10.1084/jem.176.3.679
发表时间：
1992-09-01
期刊：
The Journal of experimental medicine
影响因子：
--
作者：
Jacob J;Kelsoe G
通讯作者：
Kelsoe G
影响因子：
15.3
作者：
JACOB, J;KASSIR, R;KELSOE, G
通讯作者：
KELSOE, G