A Novel Anti-Cadherin-19 Monoclonal Antibody (Ca19Mab-8) for Flow Cytometry, Western Blotting, and Immunohistochemistry

The type II cadherin Cadherin-19 (CDH19) plays a crucial role in neural crest development. CDH19 regulates cell-cell junctions and migration by forming catenin-cytoskeleton complexes. Although anti-CDH19 monoclonal antibodies (mAbs) are used for specific applications such as Western blotting and immunohistochemistry (IHC), suitable anti-CDH19 mAbs for flow cytometry are limited. Therefore, developing mAbs that specifically recognize cell-surface-expressed CDH19 is essential for advancing both basic research and therapeutic strategies. Here, novel anti-human CDH19 mAbs (Ca₁₉Mabs) were created using flow cytometry-based high-throughput screening. One clone, Ca₁₉Mab-8 (IgG₁, κ), specifically recognized CDH19-overexpressed Chinese hamster ovary-K1 cells but did not bind to other 21 CDHs (including both type I and type II CDHs) in flow cytometry. Additionally, Ca₁₉Mab-8 recognized endogenous CDH19 in the human glioblastoma cell line LN229. The dissociation constant (<i>K</i>_D) of Ca₁₉Mab-8 for LN229/CDH19 was 9.0 × 10^-9 M. Ca₁₉Mab-8 also detected endogenous CDH19 in Western blotting. Furthermore, Ca₁₉Mab-8 can detect CDH19 in IHC using human melanoma tissue. These findings suggest that Ca₁₉Mab-8 is a novel mAb that detects cell-surface-expressed CDH19 with high specificity and is suitable for various applications in basic research. Therefore, Ca₁₉Mab-8 has potential for clinical diagnosis and tumor therapy.