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Updated: May 13, 2026

Functional Characterization of Regulatory Macrophages That Inhibit Graft-reactive Immunity
Published on: June 7, 2017
Tumor necrosis factor-α blocks differentiation and enhances suppressive activity of immature myeloid cells during
Moshe Sade-Feldman1, Julia Kanterman, Eliran Ish-Shalom
1The Lautenberg Center for General and Tumor Immunology, The Institute for Medical Research Israel-Canada.
Abstract:
Elevated concentrations of tumor necrosis factor-α (TNF-α) are detected in pathologies characterized by chronic inflammation. Whether TNF-α plays a role in manipulating the host's immune system toward generating an immunosuppressive milieu, typical of ongoing chronic inflammation, is unclear. Here we showed that TNF-α exhibited a dual function during chronic inflammation: arresting differentiation of immature myeloid-derived suppressor cells (MDSCs) primarily via the S100A8 and S100A9 inflammatory proteins and their corresponding receptor (RAGE) and augmenting MDSC suppressive activity. These functions led to in vivo T and NK cell dysfunction accompanied by T cell antigen receptor ζ chain downregulation. Furthermore, administration of etanercept (TNF-α antagonist) during early chronic inflammatory stages reduced MDSCs' suppressive activity and enhanced their maturation into dendritic cells and macrophages, resulting in the restoration of in vivo immune functions and recovery of ζ chain expression. Thus, TNF has a fundamental role in promoting an immunosuppressive environment generated during chronic inflammation.
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