Institute of Immunology National Research Center, Federal Medical and Biological Agency of Russia, Moscow, 115522, Russia.
Orekhovich Institute of Biomedical Chemistry, Moscow, 119121, Russia.
Biochemistry (Mosc). 2020 Sep;85(9):1064-1081. doi: 10.1134/S0006297920090060.
Tn antigen is a tumor-associated antigen that appears on cancer cells as a result of aberrant O-glycosylation. The most studied form of Tn antigen is found in mucins, in particular, in mucin 1 (MUC1). Antibodies against this form of Tn antigen are used to diagnose tumors, as well as to generate T-killers with a chimeric receptor. Some carcinomas do not carry MUC1 and antibodies of a different specificity are required to detect Tn antigen on these cells. In our work, we searched for anti-Tn antibodies without preliminary assumptions about the proteins that may be carriers of the Tn antigen. For this purpose, we obtained several pairs of isogenic cell lines with the wild type and knockout of the Cosmc gene, which is essential for correct protein O-glycosylation. Using the created lines as immunogens, we generated a monoclonal antibody AKC3, which reacted with the Cosmc-deficient A549 lung adenocarcinoma cells and did not bind to the wild-type cells. Using mass spectrometry, as well as co-immunoprecipitation, it was shown that the AKC3 antibody recognized the Tn antigen in the context of CD44 protein - a protein important for tumor growth. The AKC3 antibody can be used for tumor diagnosis, and to generate T cells with a chimeric receptor for treatment of tumors that do not express mucins.
Tn 抗原是一种肿瘤相关抗原，由于异常的 O-糖基化，它出现在癌细胞上。研究最多的 Tn 抗原形式存在于粘蛋白中，特别是在粘蛋白 1（MUC1）中。针对这种形式的 Tn 抗原的抗体被用于诊断肿瘤，以及生成带有嵌合受体的 T 细胞杀伤剂。一些癌没有携带 MUC1，需要具有不同特异性的抗体来检测这些细胞上的 Tn 抗原。在我们的工作中，我们搜索了没有关于可能携带 Tn 抗原的蛋白质的先验假设的抗 Tn 抗体。为此，我们获得了几对具有野生型和 Cosmc 基因敲除的同基因细胞系，Cosmc 基因对于正确的蛋白质 O-糖基化是必不可少的。使用创建的系作为免疫原，我们生成了一种单克隆抗体 AKC3，它与缺乏 Cosmc 的 A549 肺腺癌细胞反应，而不与野生型细胞结合。通过质谱分析以及共免疫沉淀，表明 AKC3 抗体在 CD44 蛋白的背景下识别 Tn 抗原 - CD44 蛋白是肿瘤生长的重要蛋白。AKC3 抗体可用于肿瘤诊断，并可用于生成不表达粘蛋白的肿瘤的嵌合受体 T 细胞治疗。
