Figure 4.

BAFF priming induces an epigenetic trained immunity phenotype in BV2 cells. (A, B) BV2 cells were treated with 10ng/ml BAFF or vehicle for 24 h and kept for 5 days. ChIP assay was performed using an antibody against histone 3 lysine 4 trimethylation (H3K4me3) or control IgG. The enrichment of H3K4me3 at the promoters of TNF-α (A) and IL-6 (B) was quantified by quantitative real-time PCR. The results are expressed as % input and data are means ± SED (n = 6); t-test; *p < 0.05. (C, D) BV2 cells were treated as indicated with 10 ng/ml BAFF, 20 mM MTA (histone methyltransferase inhibitor) or vehicle for 24 h, rested for 5 days, on day 6 treated with LPS restimulation for 24 h. TNF-α (C) and IL-6 (D) were measured in the supernatants by ELISA on day 7(n = 12). On day 6, BV2 cells were restimulated with BAFF instead of LPS. On day 7, TNF-α (E) and IL-6 (F) were measured in the supernatants (n = 12). Data are means ± SED (n = 12); Kruskal-Wallis test with Turkey post hoc test; *p < 0.05, **p < 0.01, and ***p < 0.001.