Ca₁₃Mab-17, a Novel Anti-Cadherin-13 Monoclonal Antibody for Versatile Applications

Cadherin-13 (CDH13), part of the cadherin family, is attached to the plasma membrane through glycosylphosphatidylinositol. CDH13 plays essential roles in the development of the neurological and vascular systems and is a risk factor for neural and cardiovascular diseases. CDH13 is expressed on the plasma membrane in both mature and uncleaved precursor forms with the prodomain. Although several anti-CDH13 monoclonal antibodies (mAbs) are available for basic research, there have been no reports of anti-CDH13 mAbs suitable for flow cytometry that can detect both the mature form and the uncleaved precursor. In this study, we developed novel anti-human CDH13 mAbs (named Ca13Mabs) using the mature form of CDH13 expressed in cells as an antigen. Among these, a clone Ca13Mab-17 (IgG2b, κ) specifically recognized the CDH13-overexpressed Chinese hamster ovary-K1 (CHO/CDH13) cells with no detectable cross-reactivity toward 21 other cadherins by flow cytometry. Ca13Mab-17 also detected endogenous CDH13 in human glioblastoma (LN229 and U87MG) and lung mesothelioma (NCI-H2052) cell lines. The dissociation constant (KD) value of Ca13Mab-17 for LN229 was estimated at 3.2 × 10⁻8 M. Furthermore, Ca13Mab-17 detected both the mature form and the uncleaved precursor of CDH13 in western blotting. It also identified new blood vessels and glioblastoma cells by immunohistochemistry. Overall, these findings suggest that Ca13Mab-17 is a versatile tool for detecting whole CDH13 and has potential for tumor diagnosis and therapy.