The H5C6 monoclonal antibody specifically binds to CD63. CD63 is a 53 kDa, type III lysosomal glycoprotein, expressed on activated platelets, monocytes and macrophages. This molecule is also referred to in the literature as LIMP, gp55, melanoma-associated antigen ME491, Pltgp40, LAMP-3 and is a member of the tetraspan transmembrane 4 superfamily (TM4SF). It is widely expressed on surface and in the cytoplasm of various hematopoietic (monocytes, macrophages) and non-hematopoietic (endothelium, fibroblasts, osteoclasts, smooth muscle) cells. CD63 plays roles in mediating cellular adhesion and motility.
Clone H5C6 also crossreacts with thrombin-activated peripheral blood platelets of baboon, and both rhesus and cynomolgus macaque monkeys. The distribution of H5C6+ activated platelets is similar to that observed with activated platelets from peripheral blood of normal human donors.