Splenocytes from mice that underwent passive transfer with IgG from hMOR/CHO-injected mice are sensitized to CD95-mediated apoptosis.

Purified serum IgG (100 μg) from mice injected with either PBS (○), CHO cells (▵), or recombinant hMOR/CHO cells (■) were transferred by intravenous injection into naive BALB/c mice. Twenty-four hours later, the mice given IgG injections were killed. Shown is the percentage of subdiploid nuclei when splenocytes were incubated in the presence of anti-Fas IgG mAb Jo2 for 24 hours. Nuclei DNA peak was analyzed by cytofluorometry after incubation of the cells in hypotonic medium containing propidium iodide. Each experiment was performed in duplicate. Basal apoptosis of splenocytes in the absence or presence of hamster anti-KLH IgG mAb was 8% ± 2%.