Used in immunological research to study T-cell activation and co-stimulatory signaling pathways. Serves as a ligand for OX40 receptor, playing a key role in enhancing T-cell survival, proliferation, and cytokine production. Applied in the development and testing of therapeutic antibodies targeting immune checkpoints. Utilized in cell-based assays and protein-protein interaction studies to evaluate immune response modulation. The His tag facilitates purification and detection in experimental systems, making it valuable for in vitro and preclinical studies in immunotherapy and autoimmune disease research.