Description: The Ber-ACT8 monoclonal antibody reacts with human CD103, the αE integrin. CD103 non-covalently associates with integrin β7. CD103 is expressed mainly on intraepithelial lymphocytes and a small subset of peripheral lymphocytes. CD103 is also expressed by hairy cell leukemia (HCL) and by some chronic B cell lymphocytic leukemias. In vitro stimulation of human T cells with mitogens induces upregulation of CD103. Epithelial cell antigen (E-cadherin) binds to CD103 and mediates homing of lymphocytes to the intestinal epithelium. Cross-blocking studies suggest that B-Ly7 and Ber-ACT8 see different epitopes.