Epitope Mapping of Anti-Diacylglycerol Kinase Zeta Monoclonal Antibody DzMab-1 for Immunohistochemical Analyses.

The diacylglycerol kinases (DGKs) catalyze the phosphorylation of the cell membrane lipid diacylglycerol (DG), which is important in lipid biochemistry and signal transduction into phosphatidic acid. DG-mediated signal transduction downstream of the T cell receptor has been reported to be terminated by DGKζ, 1 of 10 DGK isoforms in most cases. We previously established an anti-DGKζ monoclonal antibody (mAb) DzMab-1 (rat IgG ₁ , kappa), which reacts with both mouse DGKζ and human DGKζ (hDGKζ). In this study, we characterized the binding epitope of DzMab-1 using Western blotting, and found that Met1 and Pro3 residues of hDGKζ are important for facilitating DzMab-1 binding to hDGKζ. Furthermore, DzMab-1 was shown to be useful for immunohistochemical analyses for formalin-fixed paraffin-embedded HeLa cells. These findings could be applied for the production of more functional anti-hDGKζ mAbs.