IL-17 receptor A signaling impedes NF-κB p50/p50 repressor and subverts B-cell anergy in BXD2 mice

• Published in: The Journal of immunology (1950) 2016-05, Vol.196 (1_Supplement), p.210-210.7
• Main Authors: Hsu, Hui-Chen, Hamilton, Jennie A, Wu, Qi, Yang, PingAr, Luo, Bao, Xie, Shutao, Liu, Shanrun, Li, Jun, Mountz, John D
• Format: Article
• Language: English
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.196.Supp.210.7

B-cell fate decision checkpoint 2 at the transitional T2 stage represents a critical checkpoint defect in the development of autoimmune disease. We have found that there is a failure of anergy induction in the CD93+IgM+CD23+ transitional T2 B cells in the spleen of lupus prone BXD2 mice, which is associated with B-cell tolerance loss to anti-IgM or TLR7 in vitro. Interestingly, there was an enhanced BXD2-Il17ra−/− T2 B cell anergy phenotype in vivo, which is associated with a strong B cell anergic response to BCR or TLR7 stimulation in vitro. Abnormal survival of T2 B cells is thought to be regulated through a strong BAFF-R signaling. Surprisingly, despite normal expression of BAFF-R, BlyS cannot reverse the anergic response of BXD2-Il17ra−/− B cells to BCR stimulation. Analysis of the expression of IL-17RA in the B-cell subsets in BXD2 mice shows that only T2 and germinal center (PNA+Fas+) B cells, but not T1, T3 or mature (CD93−) B cells express surface IL-17RA. Single cell analysis of T2 B cells reveals the co-expression of Il17ra with B-cell activation gene, Bclxl. The strong anergic phenotype of BXD2-Il17ra−/− mouse B cells is associated with a dramatically enhanced nuclear expression of NF-κB1 (p50) and down-modulation of NF-κB phospho-p65. Our results suggest that, in BXD2-Il17ra−/− B cells, the anergy phenotype is established at the T2 stage. In these B cells, the stimulus-specific transcription repressor p50/p50 homodimer may act as a master transcriptional regulator to counteract pro-activation/survival NF-κB signaling provided by other major B-cell stimulators to enforce B cell anergy. Reagents that can promote the NF-κB p50/p50 repressome complex may be a novel strategy to enhance B-cell tolerance for autoimmunity.