The CD20 (HI47) antibody recognizes a 33-37 kDa type-III non-glycosylated phosphoprotein spanning the cell membrane four times therefore called TM4. CD20 antigen is e, Xenopus/Amphibian,pressed on pre-B cells, resting/activated B cells and corresponding neoplastic B cells, but is absent from plasma cells. CD20 regulates B lymphocyte activation and proliferation. The antibody also reacts with several dendritic, endothelial, epithelial, activated T cells and macrophages. The antibody stains 8-16% of normal peripheral blood lymphocytes. The CD20 (HI47) Antibody inhibits B lymphocyte activation and proliferation.