Used in immunological research to study T-cell activation and co-stimulatory signaling pathways. Serves as a soluble receptor to modulate OX40-OX40L interactions in experimental models of autoimmunity, cancer, and inflammation. Employed in binding assays and ELISA to detect OX40 ligand expression. Supports development of therapeutic antibodies and checkpoint modulators by providing a standardized target for screening and characterization. Also used in protein-protein interaction studies and structural analysis due to its tagged format, enabling detection and purification.