Effect of anti–IL-2 neutralizing MoAb on anti-CD3-induced apoptosis and Fas/FasL expression. 3DO cells were cultured in 96-well plates coated with anti-CD3 MoAb (1 μg/mL), in the presence or absence of anti–IL-2 neutralizing MoAb (10 μg/mL). Apoptosis (A), Fas (B), and FasL (C) expression were evaluated by flow cytometric analysis after 18 hours of culture, as described in Materials and Methods. The percentage of apoptotic nuclei, the Fas histogram median, the percentage of FasL⁺ cells, of a representative experiment, are indicated in each histogram.