Development and characterization of Ea₇Mab-10: A novel monoclonal antibody targeting ephrin type-A receptor 7

Abstract

The Eph receptor-ephrin system is essential for embryonic, neural, and vascular development and contributes to tumor promotion or suppression. Ephrin type-A receptor 7 (EphA7) has been identified as a tumor suppressor often lost or downregulated in lymphomas. In contrast, EPHA7 mutations have been suggested as potential driver genes in other cancers. However, the detailed molecular function has not been clarified. Therefore, a monoclonal antibody (mAb) against EphA7 is essential for basic research and clinical applications. In this study, we developed a novel anti-human EphA7 mAb, Ea₇Mab-10, using the Cell-Based Immunization and Screening (CBIS) method. Ea₇Mab-10 reacted with EphA7-overexpressed Chinese hamster ovary-K1 (CHO/EphA7) and EphA7-overexpressed LN229 (LN229/EphA7) in flow cytometry. The binding affinities were determined as 3.1 × 10⁻⁹ M for CHO/EphA7 and 6.9 × 10⁻⁹ M for LN229/EphA7. Furthermore, Ea₇Mab-10 did not show cross-reactivity with other Eph family members and was suitable for Western blotting and immunohistochemistry. These results demonstrate that Ea₇Mab-10, developed using the CBIS method, supports basic research on EphA7 and could be used for mAb-based targeted therapies.

Keywords

Eph receptor / Ephrin type-A receptor 7 / Cell-Based Immunization and Screening method / Monoclonal antibody / Flow cytometry / Western blotting / Immunohistochemistry

Acknowledgments

None.

Funding

This research was supported in part by the Japan Agency for Medical Research and Development (AMED) under grant numbers JP25am0521010, JP25ama121008, JP25ama221339, and JP25bm1123027, all awarded to Y.K., and by the Japan Society for the Promotion of Science (JSPS) Grants-in-Aid for Scientific Research (KAKENHI) under grant numbers 24K18268 (to T.T.) and 25K10553 (to Y.K.).

Conflict of interest

The authors declare that they have no competing interests.

Author contributions

Conceptualization: Mika K. Kaneko, Yukinari Kato

Formal analysis: Hiroyuki Suzuki, Haruto Yamamoto

Funding acquisition: Tomohiro Tanaka, Yukinari Kato

Investigation: Shiori Fujisawa, Haruto Yamamoto, Tomohiro Tanaka

Methodology: Mika K. Kaneko

Writing-original draft: Shiori Fujisawa, Hiroyuki Suzuki

Writing-review & editing: Yukinari Kato

Ethics approval and consent to participate

All animal experiments were approved by the Animal Care and Use Committee of Tohoku University (Approval number: 2022MdA-001).

Consent for publication

Not applicable.

Availability of data

The data presented in this study are available in the article.

Further disclosure

The paper has been uploaded to a preprint server (DOI: 10.20944/preprints202504.2395.v1).

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