Background
The 4RA10 antibody reacts with the N-terminal functional peptide of CD162 (P-selectin glycoprotein ligand-1, PSGL-1), encoded by the Selpl gene. PSGL-1 is expressed on the cell surface as a homodimer of approximately 230 kDa. In the mouse, Selpl mRNA is detected in most tissues, with high levels found in hematopoietic cells, brain, and adipose tissue. Flow cytometric analyses have revealed CD162 expression on bone marrow-derived mast and dendritic cells, splenic leukocytes, platelets, peripheral blood neutrophils, and neutrophil and T-cell lines. PSGL-1 is a ligand for P-selectin (CD62P) and is involved in leukocyte rolling, the migration of leukocytes into inflamed tissues, and responses to vascular injury. It is a sialomucin that must be specifically sialylated, fucosylated, and sulfated to bind P-selectin. There is also evidence that other ligands for PSGL-1 and CD62P may exist. 4RA10 mAb is reported to block the binding of mouse leukocytes to CD62P and CD62L.