Fig. 1: CD154 stimulation drives ex vivo expansion of human IL-10⁺ B cells for up to 14 days.

a Human CD19⁺ B cells were co-cultured with CD154⁺ or CD154⁻ CHO cells for 7 days at different CHO:B-cell ratios and in the presence of IL-2, IL-4 and IL-10. Expansion factor is ratio of the number of live CD19⁺ B cells at each day to the original number of live CD19⁺ B cells on day 0 (expansion factor at day 0 = 1). Purity of CD19⁺ B cells >96% in all experiments. Data from experiments performed with cells from different healthy donors (n = 5) are presented. Each dot is an individual response. b Representative FACS plots and summarised data of IL-10 expression by human CD19⁺ B cells which were expanded at different CD154⁺ CHO cell:CD19⁺ B-cell ratios, are shown. Gating is on fluorescence-minus-one (FMO) controls. Data from experiments performed with cells from different healthy donors (n = 5) are presented. Each dot is an individual response. c Summarised data of IL-10 production by human CD19⁺ B cells, which were expanded at different CD154⁺ CHO cell-CD19⁺ B-cell ratios, are shown. Data from experiments performed with cells from different healthy donors (n = 5) are presented. Each dot is an individual response. d Increased proliferation and % increased IL-10 expression by expBreg following 7-day expansion results in >300-fold expansion of human CD19⁺IL-10⁺ B cells. Expansion factor is the ratio of the number of live CD19⁺IL-10⁺ B cells to the original number of live CD19⁺IL-10⁺ B cells on day 0 (expansion factor at day 0 = 1). Data from experiments performed with cells from different healthy donors (n = 3) are presented. e Human CD19⁺IL-10⁺ B-cell expansion could be maintained in culture for at least 14 days when CD154⁺ CHO cells were replaced at day-3 and day-7 within the ex vivo culture system, resulting in almost 900-fold expansion. Data from experiments performed with cells from different healthy donors (n = 3) are presented. Error bars in each panel represent Mean ± SD (a–e). One-way ANOVA with Tukey’s multiple comparisons test (a–d) and 2-tailed paired t test (e) were used. Source data are provided as a Source Data file.