Human B-cell ontogeny in humanized NOD/SCID γcnull mice generates a diverse yet auto/poly- and HIV-1-reactive antibody repertoire
Human B-cell ontogeny in humanized NOD/SCID γcnull mice generates a diverse yet auto/poly- and HIV-1-reactive antibody repertoire
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DOI：
10.1038/gene.2012.16
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发表时间：
2012-07-01
影响因子：
5
通讯作者：
Marasco, W. A.
中科院分区：
文献类型：
--
作者：
Chang, H.;Biswas, S.;Marasco, W. A.
在人类免疫系统的小鼠模型中确定人类抗体(Ab)谱的特征对于确定它们在翻译研究中的相关性是至关重要的。移植人脐血源CD34(+)干细胞8~10个月后，从NOD/SCID-Gamma(Null)(HNSG)小鼠骨髓和外周血中分离出单个人B细胞。扩增了人免疫球蛋白可变区(V-H)和kappa(V-kappa)基因，将同源的V-H-V-kappa基因对组装成单链可变区Fc抗体(ScFvFcs)，并进行了功能研究。虽然V-H基因的总体分布与正常人类抗体谱相似，但对成熟B细胞亚群中V-H-第三互补决定区的分析显示，长度和正电荷增加，提示自身免疫特征。此外，70%的V-kappa序列利用了V(Kappa)4-1，这是一种与自身免疫相关的生殖系基因。成熟的B细胞亚群来源的ScFvFcs表现出最高的自身反应性和多特异性，提示检查点控制机制存在缺陷。此外，这些scFvFcs显示与重组HIV包膜结合，证实了先前在抗HIVgp140抗体中观察到的多聚/自身反应。这些数据支持这样的假设，即抗HIV广谱中和抗体可能来源于逃避免疫消除的自身/多特异性抗体，hNSG小鼠可能为研究抗HIV中和抗体反应的起源提供一个新的实验平台。
Characterization of the human antibody (Ab) repertoire in mouse models of the human immune system is essential to establish their relevance in translational studies. Single human B cells were sorted from bone marrow and periphery of humanized NOD/SCID gamma c(null) (hNSG) mice at 8-10 months post engraftment with human cord blood-derived CD34(+) stem cells. Human IG variable heavy (V-H) and kappa (V-kappa) genes were amplified, cognate V-H-V-kappa gene-pairs assembled as single-chain variable fragment-Fc Abs (scFvFcs) and functional studies were performed. Although overall distribution of V-H genes approximated the normal human Ab repertoire, analysis of the V-H-third complementarity-determining regions in the mature B-cell subset demonstrated an increase in length and positive charges, suggesting autoimmune characteristics. Additionally, >70% of V-kappa sequences utilized V(kappa)4-1, a germline gene associated with autoimmunity. The mature B-cell subset-derived scFvFcs displayed the highest frequency of autoreactivity and polyspecificity, suggesting defects in checkpoint control mechanisms. Furthermore, these scFvFcs demonstrated binding to recombinant HIV envelope corroborating previous observations of poly/autoreactivity in anti-HIVgp140 Abs. These data lend support to the hypothesis that anti-HIV broadly neutralizing antibodies may be derived from auto/polyspecific Abs that escaped immune elimination and that the hNSG mouse could provide a new experimental platform for studying the origin of anti-HIV-neutralizing Ab responses.