T cells respond to TGN1412 in the presence of monocytes from HD preculture. CFSE-labeled PBMCs were cultured either at HD or LD for 48 hours. T cells and monocytes were then isolated from each culture. (A) T cells isolated from HD preculture were cocultured with monocytes isolated from LD (light bars) and HD (dark bars) cultures in the presence of OKT3 or TGN1412 at a monocyte:T cell ratio of 0.3:1. T-cell division was determined on day 4. Responses to TGN1412 were determined in the absence and presence of anti-FcγRIIb mAb. (B) As in (A) but with T cells isolated from LD preculture. The results show mean and SD from 3 donors.