Used in research to study immune regulation and glucose metabolism due to its role in T-cell activation and as a receptor for certain viruses. Employed in protein-protein interaction studies and binding assays, especially in the development of antidiabetic drugs targeting the DPP4 pathway. The Fc tag allows for easy detection and purification, and enables potential use in therapeutic fusion proteins for enhanced half-life in vivo. Also utilized in diagnostic applications to detect anti-DPP4 antibodies or to capture interacting partners in biological samples.