Apoptosis of lymphocytes from the patient and the other family members. (A) PBMCs were activated for 5 days (2 days PHA, 3 days IL2) and incubated in the absence and presence of agonistic mAb CH-11 (2.5 μg/mL) for another 24 hours. Ordinate: percent PI- and annexin-positive cells; induced minus spontaneous apoptosis is given. (B) Proliferating EBV-transformed B cells from the patient were incubated with mAb CH-11 at different concentrations. Five experiments with 2.5 μg/mL and 25 μg/mL mAb CH-11 each. Error bars indicate standard deviation. • indicates cells from a healthy donor; ♦, cells from the patient. Induced minus spontaneous apoptosis is given. Ordinate as in A.