Rapamycin combined with allogenic immature dendritic cells selectively expands CD4+CD25+Foxp3+ regulatory T cells in rats

Comparison of rapamycin and methylprednisolone for treating inflammatory muscle disease in a murine model of experimental autoimmune myositis

Idiopathic inflammatory myopathies (IIMs) are a group of autoimmune inflammatory muscle diseases. Rapamycin has been shown to ameliorate inflammation and improve muscle function in a mouse model of experimental autoimmune myositis (EAM). In the present study, the therapeutic effect of rapamycin was compared with methylprednisolone (MP) on EAM. Mice were injected with myosin for 10 days to induce EAM and were subsequently treated with rapamycin (1.5 mg/kg), MP (40 mg/kg) or placebo (DMSO) for 14 days. The rapamycin-treated group exhibited significantly decreased severe inflammation and improved muscle strength compared with the MP-treated group. The plasma transforming growth factor-β (TGF-β) concentration in the rapamycin-treated group was significantly higher compared with the placebo group. However, both treatment groups exhibited significantly lower plasma interleukin-10 levels compared with the placebo group. Moreover, splenic regulatory T cell frequency in both the rapamycin- and MP-treated animals was significantly lower than that in the animals of the placebo group. Rapamycin showed better immune suppressive effects than MP in this model of EAM, and these effects were likely to be mediated by the TGF-β signaling pathway.

Memory T cells: strategies for optimizing tumor immunotherapy

Several studies have demonstrated that memory T cells including stem cell memory (Tscm) T cells and central memory (Tcm) T cells show superior persistence and antitumor immunity compared with effector memory T (Tem) cells and effector T (Teff) cells. Furthermore, the Tcm/Teff ratio has been reported to be a predictive biomarker of immune responses against some tumors. Thus, a system-level understanding of the mechanisms underlying the differentiation of effector and memory T cells is of increasing importance for developing immunological strategies against various tumors. This review focuses on recent advances in efficacy against tumors, the origin, formation mechanisms of memory T cells, and the role of the gut microbiota in memory T cell formation. Furthermore, we summarize strategies to generate memory T cells in (ex) vivo that, might be applicable in clinical practice.

Dissecting the Multiplicity of Immune Effects of Immunosuppressive Drugs to Better Predict the Risk of de novo Malignancies in Solid Organ Transplant Patients

De novo malignancies constitute an emerging cause of morbidity after solid organ transplant (SOT), significantly affecting the long-term survival of transplant recipients. Pharmacologic immunosuppression may functionally impair the immunosurveillance in these patients, thereby increasing the risk of cancer development. Nevertheless, the multiplicity and heterogeneity of the immune effects induced by immunosuppressive drugs limit the current possibilities to reliably predict the risk of de novo malignancy in SOT patients. Therefore, there is the pressing need to better characterize the immune dysfunctions induced by the different immunosuppressive regimens administered to prevent allograft rejection to tailor more precisely the therapeutic schedule and decrease the risk of de novo malignancies. We herein highlight the impact exerted by different classes of immunosuppressants on the most relevant immune cells, with a particular focus on the effects on dendritic cells (DCs), the main regulators of the balance between immunosurveillance and tolerance.

Cellular Metabolic Regulation in the Differentiation and Function of Regulatory T Cells

Regulatory T cells (Tregs) are essential for maintaining immune tolerance and preventing autoimmune and inflammatory diseases. The activity and function of Tregs are in large part determined by various intracellular metabolic processes. Recent findings have focused on how intracellular metabolism can shape the development, trafficking, and function of Tregs. In this review, we summarize and discuss current research that reveals how distinct metabolic pathways modulate Tregs differentiation, phenotype stabilization, and function. These advances highlight numerous opportunities to alter Tregs frequency and function in physiopathologic conditions via metabolic manipulation and have important translational implications.

Recipient-Derived Allo-iTregs Induced by Donor DCs Effectively Inhibit the Proliferation of Donor T Cells and Reduce GVHD

To compare the potency of recipient-derived, antigen-specific regulatory T cells induced by different dendritic cells (DCs; iTregs) and freshly isolated natural regulatory T cells (nTregs) in preventing mouse graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation (BMT). CD4⁺ T cells from recipient BALB/c mice were stimulated with DCs from recipient BALB/c (syn-DCs), donor B6 (allo-DCs), and third-party C3H (third-party-DCs) mice to induce different iTregs. In parallel, nTregs were isolated from spleen cells of recipient BALB/c (syn-nTregs) and donor B6 (allo-nTregs) mice using magnetic-activated cell sorting. Mixed lymphocyte reaction (MLR) assays were performed to evaluate the suppressive ability of these various regulatory T cells (Tregs). Both the iTregs and nTregs were transfused to GVHD mice on Days 0, 1, 3, and 5. Body weight, GVHD score, and survival time were monitored. Peripheral Tregs were subsequently examined on Days 7, 14, 21, and 28 after BMT, while chimerism was evaluated on Days 14 and 60. Histopathology of colon, liver, and spleen were also performed. DCs markedly induced CD25⁺ and Foxp3⁺ expression on CD4⁺ T cells. The allo-DC-induced Tregs (allo-iTregs) suppressed the proliferation of alloreactive T cells better than the other iTregs/nTregs in MLR assays (P < 0.05). Meanwhile, transfusion of the allo-iTregs reduced the severity of GVHD (P < 0.05), increased survival time compared with the GVHD group (P < 0.05), and enhanced the chimerism proportion. On Day 28 after BMT, the allo-iTregs group had the highest frequency of peripheral Tregs (P < 0.05). Recipient-derived allo-iTregs induced by donor DCs included predominant clones that specifically recognized donor antigens. These allo-iTregs not only prevented GVHD by suppressing the proliferation of donor-alloreactive T cells, but also promoted engraftment, and prolonged the survival of GVHD mice. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc. Anat Rec, 302:825-836, 2019. © 2018 Wiley Periodicals, Inc.

IL-35 inhibits acute graft-versus-host disease in a mouse model

Acute graft-versus-host disease (aGVHD) is a serious complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Our previous study found that the novel anti-inflammatory cytokine IL-35 could suppress aGVHD in patients after allo-HSCT. In this study, we used C57BL/6 (B6, H-2b) mice as donors and (B6×DBA/2) F1 (BDF1, H-2b×d) mice as recipients to create a model of aGVHD and explore the relationship between IL-35 and aGVHD. The mice receiving IL-35 survived longer than did the control mice. We observed that treatment with IL-35 and RAPA could reduce the incidence of aGVHD. Additionally, this treatment inhibited intestinal and thymic epithelial cell apoptosis and liver infiltration by the donor T-cells, thereby ameliorating the enteropathy and liver injury caused by aGVHD. We found that IL-35 and RAPA also markedly suppressed TNF-α and IL-17A expression and enhanced IFN-γ expression in the intestine and liver. We measured Tregs in spleen and found that IL-35 and RAPA treatment expanded the number of Tregs in spleen. We found that the phosphorylation of STAT1 and STAT4 were inhibited in mice with aGVHD. In contrast, STAT1 and STAT4 were phosphorylated when the mice were treated with IL-35. IL-35 may have therapeutic potential in the treatment of aGVHD after allo-HSCT.

Differential regulation of Tregs and Th17/Th1 cells by a sirolimus-based regimen might be dependent on STAT-signaling in renal transplant recipients

BACKGROUND

Sirolimus (SRL), a mammalian target of rapamycin inhibitor, has been used as a de novo base therapy with steroids and mycophenolate mofetil to avoid the use of calcineurin inhibitors. Our aim was to determine whether immunoregulation is promoted after conversion from tacrolimus (TAC) to SRL.

METHODS

The study included 24 renal transplant recipients who converted from TAC to SRL therapy and 24 normal controls. The frequency of T helper (Th) cells and the presence of signal transducer and activator of transcription (STAT) proteins in peripheral blood were analyzed by flow cytometry before conversion and at 3 and 6 months after conversion. Plasma levels of interleukin (IL)-1β, interferon-γ (IFN-γ), IL-17, IL-6, and IL-10 were analyzed by the Bio-Plex® suspension array system before and at 3 months after conversion.

RESULTS

Renal transplant recipients who switched to SRL showed a significant increase in regulatory T cell (Treg) frequencies and better renal function compared with preconversion (P<0.05). The plasma concentrations of inflammatory cytokines IL-1β, IL-6, IL-17, and IFN-γ were significantly decreased after conversion to SRL. Furthermore, recipients who switched to SRL showed an increase in STAT5 activation and a decrease in STAT3 activation compared with the TAC group.

CONCLUSION

Our results indicate that conversion to SRL might both minimize calcineurin inhibitor toxicity and promote immune tolerance.

Adoptive transfusion of tolerogenic dendritic cells prolongs the survival of liver allograft: a systematic review

OBJECTIVES

To systematically review the effects of tolerogenic dendritic cells (Tol-DCs) induced by different methods on liver transplantation and their possible mechanisms of action.

METHODS

PubMed and EMbase were searched for relevant articles through 31 December 2013. The effects of Tol-DCs on liver allograft survival were semiquantitatively evaluated, and the possible mechanisms by which Tol-DCs prolong graft survival were analyzed.

RESULTS

Seven articles were included, and classified according to methods of induction, sources, and methods of infusing Tol-DCs. Tol-DCs induced from immature DCs (imDCs), with cytokines, and by gene modification induced liver transplant tolerance for 33.1 ± 32.5 days (2.7-fold vs. control), 26.17 ± 16.20 days (1.8-fold vs. control), and 11.7 ± 1.6 days (2.3-fold vs. control), respectively. DCs derived from recipient bone marrow, donor bone marrow, and donor spleen induced liver transplant tolerance for 51.0 ± 0.0 days (5.9-fold vs. control), 21.4 ± 26.8 days (2.4-fold vs. control), and 15.0 ± 0.0 days (2.3-fold vs. control), respectively. The primary mechanisms by which Tol-DCs induce liver transplant tolerance were the induction of T-cell hyporeactivity and Th2 differentiation.

CONCLUSIONS

Tol-DCs induced by three different methods could extend liver allograft survival, with imDCs showing optimal results. The optimal infusion method was intravenous injection of 1-2 × 10(6) Tol-DC, similar to findings in renal transplantation. Tol-DCs prolonged liver transplant tolerance more than renal transplant tolerance.

Changes of CD4(+) CD25(+) Regulatory T Cells, FoxP3 in Adjuvant Arthritis Rats with Damage of Pulmonary Function and Effects of Tripterygium Glycosides Tablet

Objective. To observe the effects of tripterygium glycosides tablet (TPT) on swelling degree, arthritis index (AI), pulmonary function, cytokines, the expression of regulatory T cells (Treg), and Foxp3 in rats of adjuvant arthritis. Methods. Rats were averagely divided into normal control (NC) group, model control (MC) group, methotrexate (MTX) group, and tripterygium glycosides tablet (TPT) group. Except for the rats of normal group, the others were intracutaneously injected with 0.1 mL of Freund's complete adjuvant in the right hindlimb. NC group and MC group were treated with physiological saline. MTX group and TPT group were treated with MTX, TPT, respectively. Results. The levels of swelling degree, AI, the alveolar inflammation integral, TNF alpha (TNF-α), and endothelium-1 (ET-1 ) in MC group were significantly increased (P < 0.01), and the levels of forced vital capacity (FVC), 25% vital capacity of the peak expiratory flow (FEF(25)), 50% vital capacity of the peak expiratory flow (FEF(50)), 75% vital capacity of the peak expiratory flow (FEF(75)), maximum midexpiratory flow (MMF), peak expiratory flow (PEF), interleukin-10 (IL-10), CD4(+) CD25(+) Treg, and Foxp3 were decreased (P < 0.01). The scores of alveolitis and ET-1 were decreased with treatment of TPT. The levels of FVC, FEF(25), FEF(50), FEF(75), MMF, PEF, IL-10, and CD4(+) CD25(+) Treg in peripheral blood were increased. The expressions of Foxp3 protein and mRNA in lung tissue were also increased in TPT group. Conclusions. The paw swelling can be inhibited by TPT, and the inflammatory response in lung tissue was also decreased, which is a significant improvement in pulmonary function. The mechanism is probably associated with upregulating the expression of IL-10, Foxp3, and downregulating the level of TNF-α.