Satofuka Hiroyuki, Suzuki Hiroyuki, Tanaka Tomohiro, Li Guanjie, Kaneko Mika K, Kato Yukinari
Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8575, Japan.
Biochem Biophys Rep. 2025 Apr 1;42:101998. doi: 10.1016/j.bbrep.2025.101998. eCollection 2025 Jun.
Ephrin type A receptor 2 (EphA2) binds to membrane-bound ligands, ephrin A1, A2, and A5, eliciting bidirectional signaling. This signaling regulates many physiological processes, such as tissue development, homeostasis, and regeneration. The dysregulation of the EphA2-ephrins axis contributes to various diseases, including cancers. The high expression of EphA2 is observed in various cancers, which promotes cancer malignancy, whereas its levels are relatively low in most normal adult tissues. Therefore, EphA2 is a promising target for cancer therapy. We developed anti-human EphA2 monoclonal antibodies in this study using the Cell-Based Immunization and Screening method. Among them, a clone EaMab-7 (IgG, κ) exhibited a high affinity and sensitivity in flow cytometry. The dissociation constant values of EaMab-7 for CHO/EphA2 and MDA-MB-231 cells were determined as 6.2 ± 1.3 × 10 M and 1.6 ± 0.4 × 10 M, respectively. Furthermore, EaMab-7 can detect endogenous EphA2 in Western blot and immunohistochemistry. Therefore, the EaMab-7 is highly versatile for basic research and is expected to contribute to clinical applications, such as antibody therapy and tumor diagnosis.
EphA2受体（Ephrin A型受体2）与膜结合配体ephrin A1、A2和A5结合，引发双向信号传导。这种信号传导调节许多生理过程，如组织发育、体内平衡和再生。EphA2-ephrins轴的失调会导致包括癌症在内的各种疾病。在各种癌症中都观察到EphA2的高表达，这促进了癌症的恶性发展，而在大多数正常成人组织中其水平相对较低。因此，EphA2是一种很有前景的癌症治疗靶点。在本研究中，我们使用基于细胞的免疫和筛选方法开发了抗人EphA2单克隆抗体。其中，克隆EaMab-7（IgG，κ）在流式细胞术中表现出高亲和力和敏感性。EaMab-7对CHO/EphA2和MDA-MB-231细胞的解离常数值分别测定为6.2±1.3×10⁻⁹M和1.6±0.4×10⁻⁹M。此外，EaMab-7可以在蛋白质免疫印迹和免疫组织化学中检测内源性EphA2。因此，EaMab-7在基础研究中具有高度通用性，有望为抗体治疗和肿瘤诊断等临床应用做出贡献。
