CD43 (Sialophorin, Leukosialin) is a major sialoglycoprotein on the surface of human T lymphocytes, monocytes, granulocytes, and some B lymphocytes, which appears to be important for immune function and may be part of a physiologic ligand-receptor complex involved in T-cell activation Synonyms: Leukosialin, Leukocyte sialoglycoprotein, Sialophorin, Galactoglycoprotein, GALGP, CD43 antigen, SPN, CD43, LSN, GPL115