Development of a Sensitive Anti-Mouse CD39 Monoclonal Antibody (C39Mab-1) for Flow Cytometry and Western Blot Analyses.

CD39 is involved in adenosine metabolism by converting extracellular ATP to adenosine. As extracellular adenosine plays a critical role in the immune suppression of the tumor microenvironment, the inhibition of CD39 activity by monoclonal antibodies (mAbs) is one of the important strategies for tumor therapy. This study developed specific and sensitive mAbs for mouse CD39 (mCD39) using the Cell-Based Immunization and Screening method. The established anti-mCD39 mAb, C₃₉Mab-1 (rat IgG_2a, kappa), reacted with mCD39-overexpressed Chinese hamster ovary-K1 (CHO/mCD39) by flow cytometry. The kinetic analysis using flow cytometry indicated that the dissociation constant of C₃₉Mab-1 for CHO/mCD39 was 7.3 × 10^-9 M. Furthermore, C₃₉Mab-1 detected the lysate of CHO/mCD39 by western blot analysis. These results indicated that C₃₉Mab-1 is useful for the detection of mCD39 in many functional studies.