Department of Microbiology, The University of Alabama at Birmingham, Birmingham, United States.
Department of Microbiology and Immunology, Division of Rheumatology, Emory University, Atlanta, United States.
Elife. 2019 May 15;8:e41641. doi: 10.7554/eLife.41641.
Although B cells expressing the IFNγR or the IFNγ-inducible transcription factor T-bet promote autoimmunity in Systemic Lupus Erythematosus (SLE)-prone mouse models, the role for IFNγ signaling in human antibody responses is unknown. We show that elevated levels of IFNγ in SLE patients correlate with expansion of the T-bet expressing IgDCD27CD11cCXCR5 (DN2) pre-antibody secreting cell (pre-ASC) subset. We demonstrate that naïve B cells form T-bet pre-ASCs following stimulation with either Th1 cells or with IFNγ, IL-2, anti-Ig and TLR7/8 ligand and that IL-21 dependent ASC formation is significantly enhanced by IFNγ or IFNγ-producing T cells. IFNγ promotes ASC development by synergizing with IL-2 and TLR7/8 ligands to induce genome-wide epigenetic reprogramming of B cells, which results in increased chromatin accessibility surrounding IRF4 and BLIMP1 binding motifs and epigenetic remodeling of and loci. Finally, we show that IFNγ signals poise B cells to differentiate by increasing their responsiveness to IL-21.
虽然表达 IFNγR 或 IFNγ诱导转录因子 T-bet 的 B 细胞可促进红斑狼疮(SLE)易感小鼠模型中的自身免疫,但 IFNγ 信号在人类抗体反应中的作用尚不清楚。我们发现,SLE 患者体内 IFNγ 水平升高与 T-bet 表达的 IgDCD27CD11cCXCR5(DN2)前抗体分泌细胞(pre-ASC)亚群的扩增有关。我们证明,在 Th1 细胞或 IFNγ、IL-2、抗 Ig 和 TLR7/8 配体的刺激下,幼稚 B 细胞可以形成 T-bet pre-ASCs,并且 IFNγ 或产生 IFNγ 的 T 细胞可显著增强 IL-21 依赖性 ASC 形成。IFNγ 通过与 IL-2 和 TLR7/8 配体协同作用促进 ASC 发育,从而导致 B 细胞全基因组表观遗传重编程,导致 IRF4 和 BLIMP1 结合基序周围的染色质可及性增加,并重塑 和 基因座的表观遗传。最后,我们表明 IFNγ 信号通过增加 B 细胞对 IL-21 的反应性来促使其分化。