Effect of the blocking of different IL-2R subunits in IL-2–driven proliferation in CD3⁺ (n = 9), CD3⁺ (n = 5), and normal E+-rosetted peripheral blood lymphocytes (n = 4). Cells were preincubated with BB10 MoAb (anti-p55 IL-2R), TU27 MoAb (anti-p75 IL-2R), and TUGh4 (anti-p64 IL-2R) at the concentration of 10 μg/mL. Data are expressed as cpm × 10⁻³ ± SEM and compared with the cpm obtained following culture of patients' cells in medium containing control (ctr) isotype IgG MoAbs.