B‐cell receptor (BCR) knock‐in (KI) mouse models play an important role in vaccine development and fundamental immunological studies. However, the time required to generate them poses a bottleneck. Here we report a one‐step CRISPR/Cas9 KI methodology to combine the insertion of human germline immunoglobulin heavy and light chains at their endogenous loci in mice. We validate this technology with the rapid generation of three BCR KI lines expressing native human precursors, instead of computationally inferred germline sequences, to HIV broadly neutralizing antibodies. We demonstrate that B cells from these mice are fully functional: upon transfer to congenic, wild type mice at controlled frequencies, such B cells can be primed by eOD‐GT8 60mer, a germline‐targeting immunogen currently in clinical trials, recruited to germinal centers, secrete class‐switched antibodies, undergo somatic hypermutation, and differentiate into memory B cells. KI mice expressing functional human BCRs promise to accelerate the development of vaccines for HIV and other infectious diseases.

中文翻译：

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CRISPR / CAS9介导的带有天然人B细胞受体的临床前小鼠模型工程

B细胞受体（BCR）敲入（KI）小鼠模型在疫苗开发和基础免疫学研究中起着重要作用。但是，生成它们所需的时间构成了瓶颈。在这里，我们报告了一种一步式CRISPR / Cas9 KI方法，结合了人类种系免疫球蛋白重链和轻链在小鼠内源性基因位点的插入。我们通过快速生成三种表达天然人类前体的BCR KI系而不是通过计算推断的种系序列，来对HIV广泛中和抗体进行验证，从而验证了这项技术。我们证明了这些小鼠的B细胞具有全部功能：以受控的频率转移至同基因野生型小鼠后，此类B细胞可以通过eOD‐GT8 60mer（目前在临床试验中作为种系靶向免疫原）募集到生发中心，分泌类转换抗体，经历体细胞超突变，并分化为记忆B细胞。表达功能性人类BCR的KI小鼠有望加速开发针对HIV和其他传染病的疫苗。