Used in immunological research to study cell adhesion and leukocyte trafficking. Supports assays involving protein-protein interactions, particularly in binding studies with selectins (L-, E-, and P-selectin). Commonly employed in ELISA, surface plasmon resonance (SPR), and flow cytometry to analyze binding kinetics and inhibition. Also utilized in the development and testing of therapeutic antibodies and anti-inflammatory agents targeting PSGL-1 pathways. The His tag facilitates easy purification and detection in recombinant expression systems.