Treg cells from human blood differentiate into non-lymphoid tissue-resident effector cells upon TNFR2 costimulation

Regulatory T (Treg) cells can facilitate transplant tolerance and attenuate autoimmune- and inflammatory diseases. Therefore, it is clinically relevant to stimulate Treg cell expansion and function in vivo and to create therapeutic Treg cell products in vitro. We report that TNF receptor 2 (TNFR2) is a unique costimulus for naïve, thymus-derived (t)Treg cells from human blood that promotes their differentiation into non-lymphoid tissue (NLT)-resident effector Treg cells, without Th-like polarization. In contrast, CD28 costimulation maintains a lymphoid tissue (LT)-resident Treg cell phenotype. We base this conclusion on transcriptome and proteome analysis of TNFR2- and CD28-costimulated CD4+ tTreg cells and conventional T (Tconv) cells, followed by bioinformatic comparison with published transcriptomic Treg cell signatures from NLT and LT in health and disease, including autoimmunity and cancer. These analyses illuminated that TNFR2 costimulation promotes tTreg cell capacity for survival, migration, immunosuppression and tissue regeneration. Functional studies confirmed improved migratory ability of TNFR2-costimulated tTreg cells. Flow cytometry validated the presence of the TNFR2-driven tTreg cell signature in effector/memory Treg cells from the human placenta as opposed to blood. Thus, TNFR2 can be exploited as driver of NLT-resident tTreg cell differentiation for adoptive cell therapy or antibody-based immunomodulation in human disease. Overall design: Whole transcriptome analysis of human naïve conventional and thymus-derived regulatory CD4 T cells that were stimulated with recombinant human IL-2 and anti-CD3 agonistic mAb and costimulated with either anti-CD28 or anti-TNFR2 agonistic mAb for 7 days. Samples are derived from 5 healthy blood donors.