The antigen is a heavily glycosylated glycoprotein of apparent molecular weight 95 kDa and has a high content of Olinked carbohydrate structures (3). This major glycoprotein of thymocytes and T lymphocytes is referred to by several names including leukocyte sialoglycoprotein and leukosialin. The carbohydrate structures of leukosialin account for approximately 60 % of its weight (2). On thymocytes, this glycoprotein is the main target for binding of peanut lectin (4).Synonyms: Galactoglycoprotein, Leukocyte sialoglycoprotein, SPN, Sialophorin