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Induced CD8+FoxP3+ Treg Cells in Rheumatoid Arthritis Are Modulated by p38 Phosphorylation and Monocytes Expressing Membrane Tumor Necrosis Factor α and CD86
Author(s) -
Ellis Shawn D. P.,
McGovern Jenny L.,
Maurik André,
Howe David,
Ehrenstein Michael R.,
Notley Clare A.
Publication year - 2014
Publication title -
arthritis and rheumatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.106
H-Index - 314
eISSN - 2326-5205
pISSN - 2326-5191
DOI - 10.1002/art.38761
Subject(s) - foxp3 , cd8 , cytotoxic t cell , tumor necrosis factor alpha , t cell , immunology , peripheral blood mononuclear cell , cd86 , biology , microbiology and biotechnology , cancer research , immune system , in vitro , biochemistry
Objective Limiting the severity of inflammation and promoting its eventual resolution are vital for protecting host tissues both in autoimmunity and chronic infection. The aim of this study was to determine the suitability of repurposing anti‐CD3 monoclonal antibody (mAb) therapy for rheumatoid arthritis (RA) by analyzing its ability to induce CD8+FoxP3+ Treg cells from peripheral blood mononuclear cells (PBMCs). Methods Anti‐CD3 mAb was cultured with RA PBMCs to induce CD8+FoxP3+ Treg cells, which were analyzed by flow cytometry to determine their phenotype. Treg cell induction was investigated via neutralization or blocking antibodies, cellular depletion, or ImageStream technology. Blotting was used to determine the signaling pathways involved in CD8+FoxP3+ Treg cell induction. Suppression of CD4+ T cell effector responses was assessed by Treg cell suppression assays and Mosaic enzyme‐linked immunosorbent assay. Results Potent CD8+FoxP3+ Treg cells were induced from RA PBMCs by anti‐CD3 mAb. Unlike their CD4+ counterparts, CD8+FoxP3+ Treg cells inhibited Th17 responses in a contact‐dependent manner, thereby functioning to limit a wider range of inflammatory pathways. CD8+FoxP3+ Treg cell induction was supported both by p38 phosphorylation intrinsic to naive CD8+ T cells and by monocytes via CD86 and membrane tumor necrosis factor α (TNFα). Artificially increasing monocyte membrane TNFα or inhibiting CD8+ T cell p38 phosphorylation drove FoxP3 expression in a subset of initially unresponsive CD8+ T cells. Conclusion These data define an unknown mechanism of CD8+FoxP3+ Treg cell induction by anti‐CD3 mAb, which could be combined with a p38 inhibitor to improve therapeutic efficacy in RA patients and resolve chronic inflammation via the restoration of tolerance.