Evaluation of the effect of IL-7 on IgE production by different cell populations. (A) IL-7 does not affect IgE production by purified B cells. Tonsillar B cells were either unstimulated or stimulated with IL-7 and/or IL-4 in the absence (□) or presence (▨) of anti-CD40 MoAb. IgE were quantified in the day-12 supernatants. (B) The effect of IL-7 on IgE production requires the presence of T cells. PBMCs depleted or not (□) of monocytes (×10) (▨) or of T cells (▪) were either unstimulated or stimulated with IL-7 and/or IL-4. IgE was quantified in the supernatant of 12 days. (A and B) Results are expressed in ng/mL (as mean ± SD of quintuplicate values) and are representative of one of three separate experiments.