Gonzalez-Figueroa, PaulaRoco, Jonathan A.Papa, IleniaNúñez Villacís, LorenaStanley, MauriceLinterman, Michelle A.Dent, AlexanderCanete, Pablo F.Vinuesa, Carola G.2024-08-082024-08-082021Gonzalez-Figueroa P, Roco JA, Papa I, et al. Follicular regulatory T cells produce neuritin to regulate B cells. Cell. 2021;184(7):1775-1789.e19. doi:10.1016/j.cell.2021.02.027https://hdl.handle.net/1805/42706Regulatory T cells prevent the emergence of autoantibodies and excessive IgE, but the precise mechanisms are unclear. Here, we show that BCL6-expressing Tregs, known as follicular regulatory T (Tfr) cells, produce abundant neuritin protein that targets B cells. Mice lacking Tfr cells or neuritin in Foxp3-expressing cells accumulated early plasma cells in germinal centers (GCs) and developed autoantibodies against histones and tissue-specific self-antigens. Upon immunization, these mice also produced increased plasma IgE and IgG1. We show that neuritin is taken up by B cells, causes phosphorylation of numerous proteins, and dampens IgE class switching. Neuritin reduced differentiation of mouse and human GC B cells into plasma cells, downregulated BLIMP-1, and upregulated BCL6. Administration of neuritin to Tfr-deficient mice prevented the accumulation of early plasma cells in GCs. Production of neuritin by Tfr cells emerges as a central mechanism to suppress B cell-driven autoimmunity and IgE-mediated allergies.en-USPublisher PolicyIgEAutoantibodiesAutoimmunityFollicular helper T (Tfh)Follicular regulatory T (Tfr)Germinal center (GC)NeuritinArticle