Rituximab

• Rituximab, antiCD-20 monoclonal antibody, IDEC-C2B
• Rituximab is a chimeric murine/human monoclonal antibody based on human immunoglobulin G (IgG).
• binds to the antigen CD20, which regulates the activation process for cell cycle initiation and differentiation.
• CD20 antigen is found in normal and malignant pre-B and mature B lymphocytes, including those in over 90% of B-cell non-Hodgkin's lymphomas (NHL).
• The antigen is absent in hematopoietic stem cells, activated B lymphocytes (plasma cells) and normal tissues.
• Rituximab causes lysis of the B lymphocytes by activating the complement cascade and immune effector cells (antibody-dependent cell-mediated cytotoxicity), and inducing apoptosis.
• Rituximab depletes B lymphocytes from peripheral blood, lymph nodes and bone marrow, but does not affect hematopoietic stem cells.