Key role of macrophages in tolerance induction via T regulatory type 1 (Tr1) cells

Type 1 regulatory T (Tr1) cells play a fundamental role in maintaining and inducing immune tolerance. Our preliminary study demonstrated that an interleukin- (IL-) 10-mediated pathway is a possible regulatory mechanism underlying the xenoantigen-specific human Treg enhanced suppressive capacity. Here, we developed a feasible protocol for expanding IL-10-induced xenoantigen-specific human Tr1 cells in vitro which would be more efficient in transplantation immunotherapy efficiency. In this study, xenoantigen-specific Tr1 cells are generated from human naive CD4+ T cells expanded for two subsequent xenoantigen-stimulation cycles with recombinant human IL-10. The phenotype and suppressive capacity of xenoantigen-stimulated Tr1 cells are assessed, and the mechanism of their suppression is studied. Tr1 cells can be induced by porcine xenoantigen stimulation combined with IL-10, IL-2, and IL-15, displaying an increased expression of CD49b, CTLA-4, and LAG-3 without expressing Foxp3 which also showed an effector memory Treg phenotype and expressed high levels of CD39. After xenoantigen stimulation, the IL-10 and IL-5 gene expression in Tr1 cells increased, secreting more IL-10, and xenoantigen-stimulated Tr1 cells changed their T cell receptor (TCR) Vβ repertoire, increasing the expression of TCR Vβ2, TCR Vβ9, and TCR Vβ13. In a pig to human mixed lymphocyte reaction (MLR), xenoantigen-stimulated Tr1 cells displayed enhanced suppressive capacity via CD39 in a dose-dependent manner. Moreover, IL-5 could affect the proliferation of xenoantigen-specific Tr1 cells, but not their phenotypes’ expression. This study provides a theory and feasible method for immune tolerance induction in clinical xenotransplantation.

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Deficiency in the frequency and function of Tr1 cells in IgAV and the possible role of IL-27

Rheumatology ◽

10.1093/rheumatology/keaa752 ◽

2020 ◽

Author(s):

Lu Pan ◽

Jinghua Wang ◽

Jinxiang Liu ◽

Lishuang Guo ◽

Sirui Yang

Keyword(s):

Peripheral Blood ◽

Kidney Tissue ◽

Vitro Assay ◽

Immune Mediated ◽

Early Growth Response Gene ◽

And Function ◽

Tr1 Cells

Abstract Objective Type 1 regulatory T (Tr1) cells are involved in the pathogenesis of numerous immune-mediated diseases. However, little is known about whether and how Tr1 cells affect the development of IgA vasculitis (IgAV). We aimed to investigate this question in IgAV patients. Methods . Tr1 cells in peripheral blood and kidney tissue of IgAV patients were analysed by multi-parametric flow cytometry and immunofluorescence techniques. An in vitro assay of suppression of T cell proliferation and cytokine release was performed to evaluate the function of Tr1 cells. Real-time PCR and cell stimulation in vitro were used to explore the roles of IL-27 and early growth response gene 2 (EGR2). Results The frequency of Tr1 cells was decreased in peripheral blood but increased in kidney tissue from IgAV patients. A defective suppressive function of Tr1 cells in IgAV was observed. The frequency of Tr1 cells and the cytokines secreted by them were up-regulated in the presence of recombinant IL-27 in vitro. Moreover, IL-27 also increased the expression of EGR2. Furthermore, lower frequency of Tr1 cells during remission had a higher recurrence rate. Conclusion Tr1 cells are involved in the pathogenesis of IgAV. The low IL-27 in IgAV is responsible for impaired frequency and function of Tr1 cells, and EGR2 may be the specific transcription factor involved in the progression. Tr1 may be a risk factor for IgAV recurrence.

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837 Interleukin-10 drives the development of T regulatory type 1 (Tr1) cells and is a target for immunotherapy

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-sitc2020.0837 ◽

2020 ◽

Vol 8 (Suppl 3) ◽

pp. A889-A889

Author(s):

Yanchun Ma ◽

Vera Bauer ◽

Tanja Riedel ◽

Thomas Hofer ◽

Martin Roecken ◽

...

Keyword(s):

T Cells ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

Interleukin 10 ◽

Effector T Cells ◽

Ifn Γ ◽

Regulatory Type ◽

Tr1 Cells

BackgroundIn recent years, immunotherapy has become a common tool of cancer treatment. In order to define therapeutic targets, it is necessary to understand mechanisms of tumor-induced immunosuppression. In malignant B-cell lymphoma, the effects of the anti-inflammatory cytokine interleukin-10 (IL-10) remain poorly understood.MethodsTo investigate the role of IL-10 in a tumor microenvironment, we used λ-MYC-transgenic mice that spontaneously develop B-cell lymphoma. The experiments were performed either in vivo or in vitro and the cell samples were then analyzed by flow cytometry.ResultsIn MYC tumors, CD4+Foxp3- effector T cells maintained the expression of interferon-γ (IFN-γ), yet became exhausted. Within this population we found a cell fraction of unknown origin coexpressing IFN-γ and IL-10 that increased during disease progression. These cells turned out to be T regulatory type 1 (Tr1) cells, which are known to be immunosuppressive. When exposing homogeneous IFN-γ-producing T helper type 1 (Th1) cells to a MYC tumor milieu in vitro, part of these cells started to express both, IFN-γ and IL-10, and showed an increased level of programmed cell death protein 1 (PD-1). Notably, these changes diminished when an IL-10 neutralizing monoclonal antibody (mAb) was added to the coculture, indicating that IL-10 is necessary for the Tr1 development and is involved in the upregulation of PD-1. In line with these results, we treated λ-MYC mice with anti-IL-10 mAb. This therapy not only led to significantly prolonged survival but also decreased expression of PD-1 on effector T cells and increased proliferation of cytotoxic T cells.ConclusionsIn summary, these results showed the importance of IL-10 for the tumor immune escape in lymphoma. IL-10 induced a conversion from Th1 to Tr1 cells and elevated levels of PD-1. Both effects were diminished after IL-10 ablation. Thus, targeting IL-10 might be a promising new approach of immunotherapy.Ethics ApprovalAll animal studies were approved by Regierung von Oberbayern, approval number 55.2-1-54.

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