Development of Anti-Human Cadherin-26 Monoclonal Antibody, Ca ₂₆ Mab-6, for Flow Cytometry

Cadherin 26 (CDH26) is a recently identified member of the cadherin superfamily. Although <i>CDH26</i> gene expression has been reported in association with allergic inflammatory responses, the protein expression levels and the signaling pathways mediated through its interactions with other proteins remain poorly understood. This is primarily due to the lack of monoclonal antibodies (mAbs) that can recognize the intact, cell surface-expressed form of CDH26. In this study, we developed an antihuman CDH26 mAb, Ca₂₆Mab-6 (IgM, kappa), using the Cell-Based Immunization and Screening (CBIS) method. Ca₂₆Mab-6 demonstrated high sensitivity and specificity for CDH26 in flow cytometry and did not bind to Chinese hamster ovary (CHO)-K1 cells, which overexpress any of the other type I or type II cadherins. Ca₂₆Mab-6 successfully detected endogenous CDH26 protein expression in HepG2, U-87 MG, MCF7, and 293FT cells. The apparent dissociation constant of Ca₂₆Mab-6 was determined to be 9.8 ± 4.8 × 10^-9 M for CDH26-overexpressed CHO-K1 (CHO/CDH26) cells and 3.6 ± 1.0 × 10^-7 M for HepG2 cells. The detection of CDH26 expression in cancer cells may offer new insights into the potential relationship between inflammatory responses and malignant transformation. Therefore, Ca₂₆Mab-6, developed using the CBIS method, is expected to facilitate functional studies of CDH26 and contribute to the development of CDH26-targeted antibody-based therapies.