A Novel Anti-Cadherin 8 Monoclonal Antibody, Ca8Mab-4, for Versatile Applications

Cadherin-8 (CDH8) is a type II cadherin that plays crucial roles in various aspects of neural development and disease. Although anti-CDH8 monoclonal antibodies (mAbs) are available for Western blotting and immunohistochemistry (IHC), anti-CDH8 mAbs suitable for flow cytometry have not been reported. In this study, we developed novel anti-human CDH8 mAbs (named Ca8Mabs) using a flow cytometry-based high-throughput screening method. Among these, a clone called Ca8Mab-4 (IgG1, κ) specifically recognized CDH8-overexpressing Chinese hamster ovary-K1 (CHO/CDH8) cells, with no detectable cross-reactivity toward 21 other cadherins, including both type I and type II, by flow cytometry. Additionally, Ca8Mab-4 detected endogenous CDH8 in the human esophageal squamous cell carcinoma cell line TE5. The dissociation constant (KD) values for Ca8Mab-4 binding to CHO/CDH8 and TE5 were estimated to be 3.8 × 10⁻⁹ M and 4.9 × 10⁻¹⁰ M, respectively. Furthermore, Ca8Mab-4 was effective in Western blotting and IHC. Overall, these findings suggest that Ca8Mab-4 is a versatile tool for basic research and holds potential for tumor diagnosis and therapy.