A recombinant, humanized monoclonal antibody directed against CD22, a cell surface glycoprotein present on mature B-cells and on many types of malignant B-cells. After binding to CD22, epratuzumab's predominant antitumor activity appears to be mediated through antibody-dependent cellular cytotoxicity (ADCC). Check for active clinical trialsusing this agent. or A substance being studied in the treatment of certain types of non-Hodgkin lymphoma (NHL) and acute lymphoblastic leukemia (ALL). It is also being studied in the treatment of an autoimmune disease called systemic lupus erythematosus (SLE). Epratuzumab binds to a protein called CD22, which is found on B cells (a type of white blood cell) and some types of cancer cells. This may help suppress the body’s immune response and it may help kill cancer cells. Epratuzumab is a type of monoclonal antibody.