Figure 7: IL-21-induced IL-1β by cDCs is cell-death dependent.

(a,b) cDCs were treated with 100 ng ml⁻¹ IL-21, IL-6, or IL-10 for 24 h and IL-1β protein (a) and % apoptosis (b) determined. Data are from three experiments; error bars are means±s.e.m. In b, NS, P=0.076. (c) BMDCs were rested without GM-CSF for 16 h, treated with IL-21 or LPS for 4 h, and intracellular pro-IL-1β determined by flow cytometry. BMDCs were gated as CD11c^hi cells. Data are representative of two experiments with a total of six samples. (d) BMDCs were treated for 24 h with IL-21 or LPS±5 mM ATP added in the final 1 h, and IL-1β protein determined. Data are representative of three experiments with a total of eight individual samples; error bars are technical duplicates of the representative experiment. N.D., not detectable. (e,f) cDCs were treated with 20 μM of DCI for 1 h, then with IL-21 for 24 h. IL-1β protein production (e) and the % apoptotic cells was determined (f). Data are from four experiments; error bars are means±s.e.m. In f, NS, P=0.69. In Figure 6, IL-1β production in the culture supernatant was determined by ELISA. Pro-IL-1β induced by IL-21 in the culture supernatant was minimal, based on a pro-IL-1β-specific ELISA. Statistical analysis was performed by Student’s t-test.