Clone REA259 recognizes the CD53 antigen, a 35–42 kDa type II transmembrane glycoprotein, which is also known as tetraspanin-25. CD53 is expressed on all leukocytes including plasma cells, but not on platelets, erythrocytes, and non-hematopoietic tissues. CD53 mediates oxidative burst in monocytes and has been shown to interact with a number of proteins including IL-4, CD20, CD2, CD9, IL-2, VLA-4, and CD4. Cross-linking of CD53 on monocytes induces a strong increase in intracellular calcium ions, whereas a modest increase is seen in B lymphocytes. In resting B cells, the molecule transmits a co-stimulatory signal and promotes activation through the Ig receptor. 

Additional information: Clone REA259 displays negligible binding to Fc receptors.