Ibritumomab Antibody – Monoclonal

Ibritumomab is a monoclonal antibody directed against the CD20 antigen found on pre-B and mature B lymphocytes (normal and malignant). Ibritumomab binding induces apoptosis in B lymphocytes in vitro. It is combined with the chelator tiuxetan, which acts as a specific chelation site for Yttrium-90 (Y-90). The monoclonal antibody acts as a delivery system to direct the radioactive isotope to the targeted cells, however, binding has been observed in lymphoid cells throughout the body and in lymphoid nodules in organs such as the large and small intestines. Beta-emission induces cellular damage through the formation of free radicals (in both target cells and surrounding cells).
B-lymphocyte antigen CD20 is also known as B-lymphocyte surface antigen B1, Leukocyte surface antigen Leu-16, Membrane-spanning 4-domains subfamily A member 1 and MS4A1, is an activated-glycosylated phosphoprotein expressed on the surface of all B-cells beginning at the pro-B phase (CD45R+, CD117+) and progressively increasing in concentration until maturity. CD20 is expressed on all stages of B cell development except the first and last; it is present from late pro-B cells through memory cells, but not on either early pro-B cells or plasma blasts and plasma cells. It is found on B-cell lymphomas, hairy cell leukemia, B-cell chronic lymphocytic leukemia, and melanoma cancer stem cells. The protein has no known natural ligand and its function is to enable optimal B-cell immune response, specifically against T-independent antigens. It is suspected that it acts as a calcium channel in the cell membrane. CD20/MS4A1 is the target of the monoclonal antibodies (mAb) rituximab, Ibritumomab tiuxetan, and tositumomab, which are all active agents in the treatment of all B cell lymphomas and leukemias. Defects in CD20/MS4A1 are the cause of immunodeficiency common variable type 5 (CVID5) ; also called antibody deficiency due to CD20 defect. CVID5 is a primary immunodeficiency characterized by antibody deficiency, hypogammaglobulinemia, recurrent bacterial infections and an inability to mount an antibody response to antigen.

1. Wiseman GA, White CA, Witzig TE, Gordon LI, Emmanouilides C, Raubitschek A, Janakiraman N, Gutheil J, Schilder RJ, Spies S, Silverman DH, Grillo-Lopez AJ: Radioimmunotherapy of relapsed non-Hodgkin's lymphoma with zevalin, a 90Y-labeled anti-CD20 monoclonal antibody. Clin Cancer Res. 1999 Oct;5 (10 Suppl) :3281s-3286s. [PubMed:10541376]2. Goldenberg DM: The role of radiolabeled antibodies in the treatment of non-Hodgkin's lymphoma: the coming of age of radioimmunotherapy. Crit Rev Oncol Hematol. 2001 Jul-Aug;39 (1-2):195-201. [PubMed:11418316]3. Dillman RO: Monoclonal antibody therapy for lymphoma: an update. Cancer Pract. 2001 Mar-Apr;9 (2) :71-80. [PubMed:11879282]

Small volumes of anti-Ibritumomab antibody vial(s) may occasionally become entrapped in the seal of the product vial during shipment and storage. If necessary, briefly centrifuge the vial on a tabletop centrifuge to dislodge any liquid in the container`s cap. Certain products may require to ship with dry ice and additional dry ice fee may apply.

MBS156716 is an antibody targeting Ibritumomab. Reactive in Human.