Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4, CD152) is a receptor on T cells that inhibits the cell's functions. Blocking CTLA-4 with an antibody has proven effective for the treatment of cancer patients. Anti-CTLA-4 antibodies currently approved for clinical use can bind to human CTLA-4, but do not cross-react to murine CTLA-4. Here, we report the generation and characterization of a functional humanized antibody, mAb146, against both human and murine CTLA-4. Alanine scanning of CTLA-4 using mammalian cell expression cassette identified the unique epitopes of this novel antibody. In addition to the amino acid residues interacting with ligands CD80 and CD86, an N-glycosylation site on N110, conserved in CTLA-4 of human, monkey, and mouse, was identified as the specific epitope that might contribute to the cross-species binding and function of this antibody. This finding may also contribute to the understanding of the glycosylation of CTLA-4 and its related biologic function. In addition to facilitating preclinical development of anti-CTLA-4 antibodies, mAb146 may be useful as a therapeutic agent.

中文翻译：

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通过与N-糖基化表位结合，功能性抗体对人和鼠细胞毒性T淋巴细胞相关蛋白4都具有交叉反应。

细胞毒性T淋巴细胞相关蛋白4（CTLA-4，CD152）是T细胞上的一种受体，可抑制细胞功能。已证明用抗体封闭CTLA-4可有效治疗癌症患者。目前批准用于临床的抗CTLA-4抗体可以与人CTLA-4结合，但不会与鼠类CTLA-4交叉反应。在这里，我们报告针对人类和鼠类CTLA-4的功能性人源化抗体mAb146的生成和表征。使用哺乳动物细胞表达盒对CTLA-4进行丙氨酸扫描，可以确定这种新型抗体的独特表位。除了与配体CD80和CD86相互作用的氨基酸残基外，在人，猴和小鼠的CTLA-4中保守的N110上的N-糖基化位点，被鉴定为可能有助于该物种的跨物种结合和功能的特异性表位。这一发现也可能有助于理解CTLA-4的糖基化及其相关的生物学功能。除了促进抗CTLA-4抗体的临床前开发外，mAb146可用作治疗剂。