Figure 6.

Flow cytometry of leukemic cells of an adult T cell leukemia patient. (A) Pre-therapy. (B) Twenty-two hours after first infusion of 10 mg of anti-Tac labeled with ⁹⁰Y. The patient (patient 9) had a partial remission after this therapy. (C) Eighteen hours after antibody infusion during disease relapse. Cells are (1) unstained, (2) stained with goat anti-mouse-FITC, or (3) stained with added anti-Tac followed by goat anti-mouse-FITC. The difference between 2 and 3 indicates the degree of unsaturation of Tac antigen on the tumor cells in vivo.