Rat Anti-Mouse PSGL-1 (CD162) Antibody (S-5511)

PSGL-1 (P-selectin glycoprotein ligand-1) is a homodimeric, mucin-like glycoprotein expressed on the surface of leukocytes, best known as the primary ligand for P-selectin. Its extracellular domain is highly extended, spanning approximately 50 nm from the cell membrane, with the P-selectin binding site localized at the membrane-distal N-terminus, an arrangement that positions it optimally to interact with selectins under flow conditions. High-affinity binding to P-selectin requires both sulfation of N-terminal tyrosine residues and core-2 O-glycosylation of a specific threonine, a dual post-translational modification that is evolutionarily conserved across mammals. Functionally, PSGL-1 plays a critical role in the multi-step process of leukocyte recruitment during inflammation, mediating the initial "capturing" and "rolling" of leukocytes along activated endothelium through interaction with P-selectin. Beyond its adhesive function, PSGL-1 also acts as a signal-transducing receptor: upon engagement, it associates with the cytoskeleton, induces actin polarization, and triggers intracellular signaling pathways that lead to integrin activation and leukocyte arrest. In the tumor microenvironment, PSGL-1 has emerged as a novel immune checkpoint, acting intrinsically in CD8⁺ T cells to drive exhaustion upstream of PD-1; genetic or antibody-mediated blockade of PSGL-1 enhances effector T cell differentiation and synergizes with anti-PD-1 therapy to control anti-PD-1-resistant melanoma. Additionally, tumor cell-expressed PSGL-1 functions as a phagocytosis checkpoint by inhibiting ICAM-1-mediated engagement with macrophage LFA-1, thereby suppressing macrophage clearance of malignant cells; targeting PSGL-1 with humanized antibodies has shown promising efficacy in hematologic malignancies.