Li Leike, Wen Yankai, Wrapp Daniel, Jeong Jongmin, Zhao Peng, Xiong Wei, Atkins Constance Lynn, Shan Zhao, Hui Deng, McLellan Jason S, Zhang Ningyan, Ju Cynthia, An Zhiqiang
Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
Department of Anesthesiology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
Antib Ther. 2022 Nov 7;6(1):1-12. doi: 10.1093/abt/tbac027. eCollection 2023 Jan.
Acetaminophen (APAP) overdose is a leading cause of acute liver injury in the USA. The chitinase 3-like-1 (Chi3l1) protein contributes to APAP-induced liver injury (AILI) by promoting hepatic platelet recruitment. Here, we report the development of a Chi3l1-targeting antibody as a potential therapy for AILI. By immunizing a rabbit successively with the human and mouse Chi3l1 proteins, we isolated cross-reactive monoclonal antibodies (mAbs) from single memory B cells. One of the human and mouse Chi3l1 cross-reactive mAbs was humanized and characterized in both and biophysical and biological assays. X-ray crystallographic analysis of the lead antibody C59 in complex with the human Chi3l1 protein revealed that the kappa light contributes to majority of the antibody-antigen interaction; and that C59 binds to the 4α-5β loop and 4α-helix of Chi3l1, which is a functional epitope and hotspot for the development of Chi3l1 blocking antibodies. We humanized the C59 antibody by complementarity-determining region grafting and kappa chain framework region reverse mutations. The humanized C59 antibody exhibited similar efficacy as the parental rabbit antibody C59 in attenuating AILI . Our findings validate Chi3l1 as a potential drug target for AILI and provide proof of concept of developing Chi3l1 blocking antibody as a therapy for the treatment of AILI.
对乙酰氨基酚（APAP）过量是美国急性肝损伤的主要原因。几丁质酶3样-1（Chi3l1）蛋白通过促进肝血小板募集导致APAP诱导的肝损伤（AILI）。在此，我们报告了一种靶向Chi3l1的抗体作为AILI潜在治疗方法的研发情况。通过用人和小鼠的Chi3l1蛋白先后免疫一只兔子，我们从单个记忆B细胞中分离出了交叉反应性单克隆抗体（mAb）。其中一种人和小鼠Chi3l1交叉反应性mAb进行了人源化，并在生物物理和生物学分析中进行了表征。对先导抗体C59与人类Chi3l1蛋白复合物的X射线晶体学分析表明，κ轻链在抗体 - 抗原相互作用中起主要作用；并且C59与Chi3l1的4α - 5β环和4α螺旋结合，这是Chi3l1阻断抗体开发的功能表位和热点。我们通过互补决定区嫁接和κ链框架区反向突变对C59抗体进行了人源化。人源化的C59抗体在减轻AILI方面表现出与亲本兔抗体C59相似的功效。我们的研究结果验证了Chi3l1作为AILI潜在药物靶点的地位，并为开发Chi3l1阻断抗体作为AILI治疗方法提供了概念验证。
