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

Background/Objectives: 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 that can detect both the mature form and the uncleaved precursor in flow cytometry. Methods: We developed novel anti-human CDH13 mAbs (named Ca13Mabs) using the mature form of CDH13-expressed cells as an antigen. Results: Among Ca13Mabs, a clone, Ca13Mab-17 (IgG2b, κ) specifically recognized the mature and uncleaved precursor 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 4.1 × 10−8 M. Furthermore, Ca13Mab-17 detected both the mature and uncleaved precursor CDH13 in Western blotting. It also identified new blood vessels and glioblastoma cells by immunohistochemistry. Conclusions: Ca13Mab-17 is a versatile tool for detecting both mature and uncleaved precursor forms of CDH13 and has potential for tumor diagnosis and therapy.