Human T-cell antigens defined by monoclonal antibodies. Absence of T65 on committed myeloid and erythroid progenitors

The complement-dependent cytotoxicity of monoclonal T-cell antibody (T101) for normal and abnormal hemopoietic progenitors was assessed. T101 demonstrated toxicity for normal T-colony-forming cells from peripheral blood and bone marrow. Cytotoxicity was absent for normal peripheral blood and bone marrow granulocytes/macrophage (CFU-C) and erythroid (BFU-E) progenitors. The antibody was also not toxic for peripheral blood blast progenitors from patients with acute myelogenous leukemia (AML). These studies indicate the absence of the antigen defined by T101 (T65) from normal progenitor cells and from blast progenitors in patients with AML. T101 may be used in the treatment of T-cell malignancies and in the prevention of graft-versus-host disease (GVHD) without damage to normal progenitor cells.