Human antibody expression in transgenic rats: Comparison of chimeric IgH loci with human VH, D and JH but bearing different rat C-gene regions
Human antibody expression in transgenic rats: Comparison of chimeric IgH loci with human VH, D and JH but bearing different rat C-gene regions
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DOI：
10.1016/j.jim.2013.10.007
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发表时间：
2013-12-31
影响因子：
2.2
通讯作者：
Brueggemann, Marianne
中科院分区：
文献类型：
--
作者：
Ma, Biao;Osborn, Michael J.;Brueggemann, Marianne
人类抗体库在转基因动物中的表达是通过将大的人类 Ig 基因座引入小鼠中以及最近将嵌合 IgH 基因座引入大鼠中来实现的。当人 V-H、D 和 J(H) 基因与大鼠 C 区连接时，抗体表达显着增加，与完全人构建体中未发现的野生型水平相似。在这里，我们比较了含有相同人类 V-H 区（包括 22 个 V(H)、所有 D 和所有 J(H) 天然构型）但与不同的大鼠 C-H 基因和调控序列相连的四个大鼠品系。内源性 IgH 基因座被锌指核酸酶沉默。育种后，所有品系均产生了 IgM 水平接近正常的嵌合人 H 链。然而，在两个品系中观察到较差的 IgG 表达和低效的免疫反应，这意味着高表达、类别转换和超突变与 IgH 基因座 3' 端的大调节区提供的最佳增强子功能相关。此外，排除 C δ 及其下游区间区域可能有助于重组。在携带不同且不同间隔的 C 基因的两个品系中发现了与正常大鼠相似的高度多样化的 IgG 和免疫反应。 (C) 2013 作者。由 Elsevier B.V. 出版。保留所有权利。
Expression of human antibody repertoires in transgenic animals has been accomplished by introducing large human Ig loci into mice and, more recently, a chimeric IgH locus into rats. With human V-H, D and J(H) genes linked to the rat C-region antibody expression was significantly increased, similar to wild-type levels not found with fully human constructs. Here we compare four rat-lines containing the same human V-H-region (comprising 22 V(H)s, all Ds and all J(H)s in natural configuration) but linked to different rat C-H-genes and regulatory sequences. The endogenous IgH locus was silenced by zinc-finger nucleases. After breeding, all lines produced exclusively chimeric human H-chain with near normal IgM levels. However, in two lines poor IgG expression and inefficient immune responses were observed, implying that high expression, class-switching and hypermutation are linked to optimal enhancer function provided by the large regulatory region at the 3' end of the IgH locus. Furthermore, exclusion of C delta and its downstream interval region may assist recombination. Highly diverse IgG and immune responses similar to normal rats were identified in two strains carrying diverse and differently spaced C-genes. (C) 2013 The Authors. Published by Elsevier B.V. All rights reserved.