Follicular regulatory T cells produce neuritin to regulate B cells (2021) Gonzalez-Figueroa et al

Summary
Regulatory 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.

Highlights

• Tfr cells control the emergence of aberrant CD138 + germinal center B cells
• Neuritin-deficiency in Foxp3 + cells leads to spontaneous autoantibody production
• Neuritin limits IgE class switch recombination
• Exogenous neuritin suppresses conventional and aberrant plasma cell differentiation

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Press Release from the ANU: New natural answers for killer allergies

Edit: Added "Highlights"; and put in the DOI url, now that it is working.