Department of Molecular Patho-Biochemistry and Patho-Biology, School of Medicine, Yamagata University, Yamagata, Japan.
The Japanese Collaborative Research Group (JCRG) on Autoimmune Acquired Coagulation Factor Deficiencies Supported by the Japanese Ministry of Health, Labor and Welfare (MHLW), Yamagata University School of Medicine, Yamagata, Japan.
Monoclon Antib Immunodiagn Immunother. 2024 Oct;43(5):135-143. doi: 10.1089/mab.2024.0016. Epub 2024 Sep 25.
Coagulation factor XIII (FXIII) is an enzyme that strengthens hemostatic clots, and its deficiency can cause life-threatening bleeding. We immunized mice with human plasma-derived FXIII to generate monoclonal antibodies (mAbs) against the B subunit (FXIII-B), which stabilizes the A subunit (FXIII-A) of FXIII, and analyzed their properties. The epitopes of the seven mouse antihuman FXIII-B mAbs obtained were found to be the 3rd, 5th, 6th, 9th, and 10th Sushi domains. One of these mAbs, mAb 5-6C, recognized the 10th Sushi domain and inhibited the fibrin cross-linking reaction without affecting the amine incorporation activity of FXIII. We previously reported that the 10th Sushi domain is the site where FXIII-B binds to fibrin and functions to bring FXIII-A closer to the substrate fibrin. Except for mAb 5-6C, mouse mAbs with high yields were used to measure the amount of FXIII-B antigen by an immunochromatography test (ICT), which showed a high correlation with enzyme-linked immunosorbent assay-obtained results. In addition, we developed a prototype ICT to detect anti-FXIII-B autoantibodies using mAb 1-3C, which showed good results in measuring the amount of FXIII-B antigen. Thus, mouse mAbs may be useful for clinical applications. mAb 5-6C targeting the 10th Sushi domain may also be useful for inhibiting thrombosis progression when humanized as antibody medicines.
凝血因子 XIII (FXIII) 是一种增强止血凝块的酶，其缺乏可导致危及生命的出血。我们用人血浆源性 FXIII 免疫小鼠，以生成针对 FXIII-B 亚基（稳定 FXIII-A 亚基的 FXIII）的单克隆抗体（mAbs），并分析其特性。获得的七种抗人 FXIII-B mAbs 的表位被发现位于第 3、5、6、9 和 10 Sushi 结构域。其中一种 mAb，mAb 5-6C，识别第 10 Sushi 结构域，抑制纤维蛋白交联反应，而不影响 FXIII 的胺掺入活性。我们之前报道过，第 10 Sushi 结构域是 FXIII-B 与纤维蛋白结合的部位，其功能是使 FXIII-A 更接近底物纤维蛋白。除了 mAb 5-6C 之外，还使用产量较高的小鼠 mAbs 通过免疫层析试验（ICT）来测量 FXIII-B 抗原的量，其与酶联免疫吸附试验（ELISA）获得的结果高度相关。此外，我们使用 mAb 1-3C 开发了一种原型 ICT 来检测抗 FXIII-B 自身抗体，该方法在测量 FXIII-B 抗原量方面取得了良好的效果。因此，小鼠 mAbs 可能对临床应用有用。作为抗体药物进行人源化后，靶向第 10 Sushi 结构域的 mAb 5-6C 也可能有助于抑制血栓形成进展。
