In vitro stimulation of F36V-Mpl increases lymphoid output from multi-lymphoid progenitors. (A) Multilymphoid progenitors (CD34⁺CD38⁻Lin⁻CD7⁺) transduced with the F36V-MPL-GFP were cultured on MS5 stroma without growth factors with or without CID. Fold increase (mean, SEM) in total number and CD19⁺GFP⁺ cells relative to day 0 is shown (n = 5 experiments, in triplicate); P = .04 and .047, respectively. (B) FACS analysis of cells cultured (D29-35) as in panel A. (C) B-cell progenitors (CD34⁺CD19⁺) and B cells (CD34⁻CD19⁺) were transduced with F36V-MPL-GFP and cultured with or without CID on MS5 stroma without cytokines. (n = 3 wells/arm; mean ± SE).