Development of a novel anti-human glypican 5 monoclonal antibody (G₅Mab-1) for multiple applications

Glypican 5 (GPC5) is a member of heparan sulfate proteoglycans and is anchored to the plasma membrane via glycosylphosphatidylinositol. GPC5 plays an essential role in kidney, limb, and brain development. Furthermore, GPC5 is expressed in some cancers, but whether it functions as a cancer-promoting or -suppressing factor remains unclear. Therefore, the development of versatile and specific anti-GPC5 monoclonal antibodies (mAbs) is desired to clarify the biological and pathological functions of GPC5. In this study, we successfully established an anti-human GPC5 mAb (clone G₅Mab-1) using the Cell-Based Immunization and Screening method. G₅Mab-1 is capable of using flow cytometric analysis. G₅Mab-1 is specifically bound only to GPC5, not to the other GPC family members. The dissociation constant value of G₅Mab-1 for GPC5-overexpressed Chinese hamster ovary K-1 (CHO/GPC5) cells was determined as 9.9 × 10^-9 M. Furthermore, G₅Mab-1 detected GPC5 in Western blot and immunohistochemistry using CHO/GPC5 cells. Therefore, the G₅Mab-1 is highly versatile for basic research and is expected to contribute to clinical applications, such as antibody-based therapy and diagnosis of cancer.