Used in immunological research to study cell signaling pathways involved in immune regulation. Acts as a ligand or receptor mimic in binding assays to investigate interactions between immune cells, particularly T cells and NK cells. Employed in ELISA, flow cytometry, and protein-protein interaction studies to detect and quantify receptor-ligand binding. Supports development of therapeutic antibodies by serving as a target antigen in screening and characterization workflows. Also utilized in structural studies to understand the molecular basis of immune cell activation and inhibition.