Anti-CD63 recognizes an extracellular fragment of CD63，a 56-kilodalton (kDa)，type III lysosomal glycoprotein，belonging to the tetraspanin family. CD63 is expressed by granulocytes，platelets，T-cells，monocytes/macrophages，endothelial cells. CD63 protein is also expressed in exosome membrane. Cell sur-face exposition of CD63 is usually activation dependent. CD63 interacts with integrins and affects phagocytosis and cell migration，it is also involved in H/K ATPase trafficking regulation of ROMK1 channels. CD63 also serves as a T-cell co-stimulator molecule. Expression of CD63 can be used for predicting the prognosis in earlier stages of carcinomas.
