Selective activation of tumor necrosis factor receptor 2 induces anti-inflammatory responses and alleviates experimental arthritis

Objective. Treg cells modulate immune responses and can suppress the development of autoimmune diseases. Tumor necrosis factor receptor II (TNFRII) has been recognized as a key receptor on these cells that facilitates expansion and stabilization of CD4+ Treg cells. The purpose of the present study was to investigate the therapeutic activity of a novel TNFRII agonist in experimental arthritis as well as the role of different Treg cell subsets. Methods. A novel mouse TNFRII-selective fusion protein (EHD2-sc-mTNF(R2)) was generated by genetic engineering. Mouse T cells were incubated together with interleukin-2 and/or EHD2-sc-mTNF(R2), and the effects on Treg cells were analyzed by flow cytometry. Mice with collagen-induced arthritis (CIA) were treated with EHD2-sc-mTNF(R2) or saline, and the therapeutic effects were monitored and characterized. Results. Selective activation of TNFRII was found to expand both CD4+ and CD8+ Treg cells. Moreover, TNFRII activation elevated the number of CD4+CD25+ and CD8+CD25+ Treg cells and increased the number of FoxP3-expressing cells in CD8+, but not CD4+, Treg cells, indicating different mechanisms of TNFRII-induced expansion of diverse T cell subsets with suppressive activity. In the CIA model, we demonstrated that administration of the TNFRII agonist EHD2-sc-mTNF(R2) led to the expansion of both CD4+ and CD8+ Treg cells invivo and induced anti-inflammatory responses that alleviated arthritis. Conclusion. Our findings support the use of TNFRII-selective therapeutics as an effective approach to the treatment of arthritic disease and possibly other inflammatory and autoimmune diseases.