Fig. 2.
DNA synthesis by GC B cells cultured with cytokines. GC B cells were cultured for 5 days with cytokines in the presence (▪) or absence (□) of CD40 MoAb, G28-5, and then [3H]thymidine uptake was measured. The values in brackets indicate the concentration of cytokine employed in ng/mL (U/mL for IL-7). (A) GC B cells; (B) GC B cells in the presence of CD32-L cells. Data are the mean cpm ± SEM and are representative of three experiments. Values for [3H]thymidine uptake by CD32-L cells alone (∼3,000 to 7,000 cpm) have been subtracted in (B).