[Subclassification of acute leukemia and monoclonal antibodies]

Recent advances in immunological techniques, particularly, the development of monoclonal antibodies by the hybridoma technique, have contributed a great to the understanding of cell surface antigens of human hematopoietic cells. We have produced monoclonal antibodies detecting the following antigens: Ia-like (NL-12, MD-1A), Null-ALL associated (NL-1, NL-22, HL-47), T cell (ATL-27, Thy-64), myelocyte-monocyte (HL-1), and monocyte (HL-21). Using these antibodies, serological typing of leukemia was performed and it was found to facilitate considerably the diagnosis of leukemia. In consideration of therapeutic use of two antibodies detecting Null-ALL associated antigen (NL-1, NL-22), reactivity against major organs was studied by immunoperoxidase staining. NL-1 antibody was reactive with glomeli and tubules of kidney and epithelial cells of small intestine, while NL-22 antibody reacted with tubules of kidney, liver cells and some other tissues. This results suggested the difficulty of application of these antibodies directly to the patients. Reactivity against colony forming cell in bone marrow was also examined and moderate inhibition was observed by both antibodies, which might allow to eliminate ALL cells in cryopreserved autologous bone marrow cells from bone marrow transplantation patients by the treatment with appropriate concentration of antibodies.