Dipeptidyl peptidase 4 (DPP4) (DPP4)

Dipeptidyl peptidase 4 (DPP4), also known as CD26, is a multifunctional transmembrane glycoprotein that functions as both a serine protease and a co-stimulatory molecule in immune cells [1, 6]. It is the specific antigen recognized by the monoclonal antibody A6H, which was originally developed against fetal renal tissues and found to be highly reactive in renal cell carcinoma (RCC) [1, 2]. In the kidney, DPP4 is localized to the brush border of proximal tubules and is significantly overexpressed in various cancers, including RCC, where it may play a role in tumor progression and metastasis [1, 5]. Beyond its role in oncology, DPP4 is a critical regulator of glucose metabolism through the degradation of incretin hormones like glucagon-like peptide-1 (GLP-1), making it a primary therapeutic target for type 2 diabetes mellitus [1, 10]. Drugs targeting DPP4 include a class of small-molecule inhibitors known as gliptins, as well as experimental monoclonal antibodies like A6H used for imaging and radioimmunotherapy [3, 10]. The protein also serves as a functional receptor for the Middle East Respiratory Syndrome coronavirus (MERS-CoV) [1].

Other names

CD26Dipeptidyl peptidase IVDPP IVT-cell activation antigen CD26Adenosine deaminase complexing protein 2ADCP2Renal cell carcinoma-associated antigen A6HA6H antigen

DPP4 inhibition, Radioimmunotherapy, T-cell co-stimulation modulation