FIG. 2.

Effect of cytokines on the magnitude of human B-cell IgM AFC response. (A) Human CD19⁺ total B cells (1.5 × 10⁵ cell/culture) or (B) CD19⁺CD27⁻ naive B cells (1.5 × 10⁵ cell/culture) were cocultured with irradiated CD40L-L cells (3 × 10³ cell/culture) for 4 days and further cultured for additional 3 days without CD40L-L cells. Cytokines were added as indicated to individual group. Cells were harvested on day 7 to enumerate IgM-secreting cells by ELISPOT. The cell number was determined using a particle counter, and the viability was assessed by a pronase activity assay. *p < 0.05, **p < 0.01, compared with CD40L-L cell–only group. These data are representative of two separate experiments (B cells from two donors) with at least four replicates per group. Data in panels (A) and (B) were obtained using total or naive B cells from two different donors in two separate experiments. The two donors were different from the donors from which data in Figure 1 were obtained. The error bars indicate SE calculated for replicates of each treatment group. The error bars indicate SE calculated for replicates of each treatment group.