Monoclonal antibody (WI-2) reactive against human transformed and leukemic cells

A monoclonal antibody (WI-2) was produced against HL-60 cells. This antibody was IgM Kappa and reacted with human cell lines derived from fibroblasts and from hemopoetic, lymphoid, and neoplastic tissues. It also reacted with lymphocytes transformed by mitogens. WI-2 lacked reactivity against normal human RBC's, mature granulocytes, and T and B lymphocytes. The target antigen for WI-2 had a molecular weight of 43,000 daltons. Specimens from patients with leukemia were tested with WI-2. The number of immature cells was compared with the number of WI-2 reactive cells in the peripheral blood and bone marrow and subjected to linear regression analysis. There was a highly significant (p less than 0.001) correlation between the two parameters. The antibody may be useful in monitoring the progress of the patients and in detecting early relapse in leukemia.