A radioimmunoconjugate consisting of BC8, a murine IgG1 anti-CD45 monoclonal antibody labeled with iodine 131 (I-131), with radioimmunotherapeutic properties. Using monoclonal antibody BC8 as a carrier for I-131 results in the targeted destruction of cells expressing CD45. CD45 is tyrosine phosphatase expressed on virtually all leukocytes, including myeloid and lymphoid precursors in bone marrow and mature lymphocytes in lymph nodes; it is also expressed on most myeloid and lymphoid leukemic cells, but not on mature erythrocytes or platelets. or A substance being studied in the treatment of some types of leukemia and lymphoma. BC8 is a monoclonal antibody that binds to a protein called CD45, which is found on most white blood cells and some types of leukemia and lymphoma cells. It is linked to a radioactive substance called iodine I 131, which may help kill cancer cells. Iodine I 131 monoclonal antibody BC8 is a type of radioimmunoconjugate.