The CD44 (HI44a) antibody recognizes a highly glycosylated 80-90 kDa type-I transmembrane cell surface protein, which is the receptor for hyaluronic acid, also called phagocytic glycoprotein-1 (Pgp-1). CD44 antigen is widely e, Xenopus/Amphibian,pressed on most cell types including leukocytes, erythrocytes, endothelial cells and epithelial cells, but not on platelets. CD44 is involved in leukocyte attaching and rolling on endothelial cells, homing to peripheral lymphoid organs and sites of inflammation, and leukocyte aggregation.