Themis suppresses the effector function of CD8+ T cells in acute viral infection

CD8⁺ T cells play a central role in antiviral immune responses. Upon infection, naive CD8⁺ T cells differentiate into effector cells to eliminate virus-infected cells, and some of these effector cells further differentiate into memory cells to provide long-term protection after infection is resolved. Although extensively investigated, the underlying mechanisms of CD8⁺ T-cell differentiation remain incompletely understood. Themis is a T-cell-specific protein that plays critical roles in T-cell development. Recent studies using Themis T-cell conditional knockout mice also demonstrated that Themis is required to promote mature CD8⁺ T-cell homeostasis, cytokine responsiveness, and antibacterial responses. In this study, we used LCMV Armstrong infection as a probe to explore the role of Themis in viral infection. We found that preexisting CD8⁺ T-cell homeostasis defects and cytokine hyporesponsiveness do not impair viral clearance in Themis T-cell conditional knockout mice. Further analyses showed that in the primary immune response, Themis deficiency promoted the differentiation of CD8⁺ effector cells and increased their TNF and IFNγ production. Moreover, Themis deficiency impaired memory precursor cell (MPEC) differentiation but promoted short-lived effector cell (SLEC) differentiation. Themis deficiency also enhanced effector cytokine production in memory CD8⁺ T cells while impairing central memory CD8⁺ T-cell formation. Mechanistically, we found that Themis mediates PD-1 expression and its signaling in effector CD8⁺ T cells, which explains the elevated cytokine production in these cells when Themis is disrupted.

Molecular hydrogen has a positive impact on pregnancy maintenance through enhancement of mitochondrial function and immunomodulatory effects on T cells

AIMS

Molecular hydrogen (H₂) has attracted growing interest because of its implications in various diseases. However, the molecular mechanisms underlying the remarkable effect of a small amount of H₂ remain elusive. No knowledge has been available on the role of H₂ in the etiology of pregnancy disorders or its direct influence on human immune cells. Since maternal immunity, T cells in particular, plays a critical role in pregnancy maintenance. We investigated the effects of H₂ on T cells and its relation to preterm birth (PTB).

MAIN METHODS

Exhaled H₂ concentrations in pregnant women were measured and correlated with cytokine concentrations in maternal and umbilical cord blood. H₂ was added to T cells collected from healthy donors, and differentiation and proliferation were examined. Energy metabolism was also examined. H₂ was administered to mice and cytokine expression was compared.

KEY FINDINGS

Our prospective observational study revealed that maternal production of H₂ is significantly lower in pregnant women with PTB, suggesting its potential as a biomarker for predicting PTB. We found that H₂ has clear associations with several maternal cytokines, and acts as an immunomodulator by exerting mitochondrial function in human T cells. Moreover, in vivo administration of H₂ to pregnant mice regulated inflammatory responses and reduced PTB caused by T cell activation, which further supports the notion that H₂ may contribute to prolonged gestation through its immunomodulatory effect.

SIGNIFICANCE

Measuring maternal H₂-production could be a potential clinical tool in the management of PTB, and H₂ may have positive impact on pregnancy maintenance.

Increased frequency of activated regulatory T cells in patients with lupus nephritis

BACKGROUND AND OBJECTIVE

Lupus nephritis (LN) is one of the common manifestations of SLE, which affects the quality of life of patients. Abnormality in the adaptive immune response, such as T cell response, plays the main role in the pathogenesis of SLE and LN. In this study, we aimed to evaluate the role of different subpopulations of regulatory T cells (Tregs) and effector T cells (Teff) in patients with LN and compare them with SLE patients.

MATERIALS AND METHODS

A total of 48 participants were enrolled in this study and divided into three groups: (i) patients with SLE; (ii) patients with LN; and (iii) healthy controls (HCs) subjects. The frequencies of CD4⁺ CD25⁺⁺ CD45RA^- Foxp3^hi activated Tregs (aTregs), CD4⁺ CD25⁺ CD45RA⁺ Foxp3^lo resting Tregs (rTregs), CD4⁺ CD25⁺ CD45RA^- Foxp3^lo non-Tregs, CD4⁺ CD25⁺ Foxp3^- Teff, and Tregs were analyzed in all subjects using flow cytometer.

RESULTS

LN patients had a considerable increased frequency of aTregs and Tregs compared with SLE patients (standardized mean difference [SMD] 0.50; 95% CI [-0.26, 1.25]; p > 0.05 and SMD 0.60; 95% CI [-0.16, 1.36]; p > 0.05, respectively). Patients with LN had a considerable increased frequency of Teff compared with SLE patients (SMD 0.49; 95% CI [-0.26, 1.24]; p > 0.05). However, the increased ratio of Tregs/Teff was observed in patients with LN compared with SLE patients (SMD -0.25; 95% CI [-0.97, 0.48]; p > 0.05).

CONCLUSION

Patients with LN showed immunoregulatory properties, in which both aTregs and Tregs had increased frequencies.

Juzentaihoto Exerts Anti-Allergic Effects by Inhibiting Effector T-Cell Activation and Inducing and/or Activating Regulatory T Cells in a Murine Model of Contact Hypersensitivity

BACKGROUND

Juzentaihoto (JTT) is a Kampo prescription that has been used clinically for treating skin diseases such as atopic dermatitis in Japan. We have previously studied the anti-allergic effects of JTT on 2,4,6-trinitrochlorobenzene (TNCB)-induced contact hypersensitivity (CHS) in mice and demonstrated that it significantly suppresses ear swelling in a dose-dependent manner. However, the mechanism underlying the anti-allergic actions of JTT is obscure.

METHODS

We investigated the mechanism underlying the anti-allergic effects of JTT using a TNCB-induced murine CHS model and adoptive cell transfer experiments.

RESULTS

We showed that the anti-allergic effects of JTT are due to inhibition of effector T-cell activation and induction and/or activation of regulatory T cells. Furthermore, ex vivo experiments confirmed the effect of JTT on the activation of effector T cells and regulatory T cells, as interferon-γ production decreased, whereas interleukin (IL)-10 production increased, in the cultured lymphocytes obtained from 5% TNCB-sensitized mice treated with anti-CD3ε and anti-CD28 monoclonal antibodies. Flow cytometry showed that the CD4+CD25+Foxp3+, CD4+CD25+Foxp3-, and CD8+CD122+ cell population increased after oral administration of JTT. Finally, the anti-allergic effect of JTT by inducing and/or activating regulatory T cells (Tregs) was confirmed to be mediated by IL-10 through in vivo neutralization experiments with anti-IL-10 monoclonal antibodies.

CONCLUSION

We suggested that JTT exerts anti-allergic effects by regulating the activation of effector T cells and Tregs involved in murine CHS model.

Orengedokuto exerts anti-allergic effects via inhibition of effector T cell activation in a murine model of contact hypersensitivity

Orengedokuto (OGT) is a Kampo prescription that has been used for the treatment of inflammation, hypertension, gastrointestinal disorders, and liver and cerebrovascular diseases. It is also used for the treatment of skin diseases such as urticaria and atopic dermatitis. We previously studied its anti-allergic effects of OGT on the murine model of 2,4,6-trinitrochlorobenzene (TNCB)-induced contact hypersensitivity (CHS) and demonstrated that it significantly suppresses ear swelling in a dose-dependent manner. However, the mechanism underlying this activity remained unknown. Here, we sought to identify the mechanism involved. Using a murine model of TNCB-induced CHS, together with adoptive cell transfer experiments, we found that the anti-allergic effects of OGT may be due to the inhibition of effector T cell activation and not the induction and/or activation of regulatory T cells. Flow cytometry analysis revealed that oral administration of OGT suppressed the increase in CD8⁺CD44^highCD62L⁺ cell number in draining lymph nodes (dLNs) of mice sensitized with 5% TNCB. Additionally, ex vivo experiments confirmed the suppressive effect of OGT on the activation of effector T cells, as interferon-γ (IFN-γ) production by cultured lymphocytes obtained from 5% TNCB-sensitized mice and stimulated with anti-CD3ε and anti-CD28 monoclonal antibodies was reduced by OGT administration. In conclusion, our finding suggests that OGT exerts anti-allergic effects by regulating the activation of effector T cells involved in inflammatory skin diseases such as atopic dermatitis.

The MAPK dual specific phosphatase (DUSP) proteins: A versatile wrestler in T cell functionality

The functional state of T cells is diverse and under dynamic control for adapting to the changes of microenvironment. Reversible protein phosphorylation represents an important post-translational modification that not only involves in the immediate early response of T cells, but also affects their functionality in the long run. Perturbation of global phosphorylation profile and/or phosphorylation of specific signaling nodes result in aberrant T cell activity. Dual specific phosphatases (DUSPs), which target MAPKs and beyond, have increasingly been emerged as a versatile regulator in T cell biology. Herein in this mini review, we sought to summarize and discuss the impact of DUSP proteins on the regulation of effector T cell activity, T cell polarization, regulatory T cell development and T cell senescence/exhaustion. Given the distinctive engagement of each DUSP member under various disease settings such as chronic infection, autoimmune disorders, cancer and age-related diseases, DUSP proteins likely hold the promise to become a druggable target other than the existing therapeutics that are predominantly by manipulating protein kinase activity.

Reduced CD4+ CD25++ CD45RA- Foxp3hi activated regulatory T cells and its association with acute rejection in patients with kidney transplantation

BACKGROUND

It was found that regulatory T cells (Tregs) importantly affect the maintenance of the kidney graft. However, Tregs are a heterogeneous population with less to more suppressive activity. The aim of this study was to determine the effects of different subsets of Tregs, as well as their ratio to effector T cells (Teff), on kidney transplantation outcomes.

METHODS

A total of 58 participants were enrolled in this study and divided into four groups: (i) first kidney transplant recipients (stable 1); (ii) second kidney transplant recipients (stable 2); (iii) transplant recipients with acute rejection (AR); and (iv) healthy control subjects. By using flow cytometer, the frequencies of CD4⁺ CD25⁺⁺ CD45RA^- Foxp3^hi activated Tregs (aTregs), CD4⁺ CD25⁺ CD45RA⁺ Foxp3^lo resting Tregs (rTregs), CD4⁺ CD25⁺ CD45RA^- Foxp3^lo non-suppressive T cells, CD4⁺ CD25⁺ Foxp3^- cells Teff, and total Tregs were analyzed in all subjects.

RESULTS

The frequency of aTregs (as well as the ratio of aTregs/Tregs) was significantly lower in the AR patients than the other three groups. In contrast to AR patients, stables 1 and 2 had a higher aTreg/Treg ratio than those in the control group. Although patients with AR had a significantly lower total Tregs than the other three groups, the balance of total Tregs and Teff was similar between patients with and without AR.

CONCLUSION

Patients with AR had poorer immunoregulatory properties than those with normal graft functioning, as well as those in the control group. These reduced immunoregulatory properties in patients with AR could lead to graft rejection.

Immunophenotypic Analysis of CAR-T Cells

CAR-T cell immunotherapy is a promising therapeutic modality for cancer patients. The success of CAR-T cell therapy has been associated with the phenotype, activation and functional profiling of infused CAR-T cells. Therefore, immunophenotypic characterization of CAR-T cells during bioprocess is crucial for cell quality control and ultimately for improved antitumor efficacy. In this chapter, we propose a flow cytometry panel to characterize the immunophenotype of the CAR-T subsets.

Magnetic targeting of adoptively transferred tumour-specific nanoparticle-loaded CD8+ T cells does not improve their tumour infiltration in a mouse model of cancer but promotes the retention of these cells in tumour-draining lymph nodes

Background

Adoptive T cell-transfer (ATC) therapy is a highly promising cancer-treatment approach. However, in vivo-administered T cells tend to disperse, with only a small proportion reaching the tumour. To remedy this, magnetic targeting of T cells has been recently explored. Magnetic nanoparticles (MNPs) functionalised with antibodies were attached to effector T cells and magnetically recruited to tumour sites under MRI guidance. In this study, we investigated whether 3-aminopropyl-triethoxysilane (APS)-coated MNPs directly attached to CD8⁺ T cell membranes could also magnetically target and accumulate tumour-specific CD8⁺ T cells in solid tumours using an external magnetic field (EMF). As it has been shown that T cells associated with APS-coated MNPs are retained in lymph nodes (LNs), and tumour-draining LNs are the most common sites of solid-tumour metastases, we further evaluated whether magnetic targeting of APS-MNP-loaded CD8⁺ T cells could cause them to accumulate in tumour-draining LNs.

Results

First, we show that antigen-specific CD8⁺ T cells preserve their antitumor activity in vitro when associated with APS-MNPs. Next, we demonstrate that the application of a magnetic field enhanced the retention of APS-MNP-loaded OT-I CD8⁺ T cells under flow conditions in vitro. Using a syngeneic mouse model, we found similar numbers of APS-MNP-loaded OT-I CD8⁺ T cells and OT-I CD8⁺ T cells infiltrating the tumour 14 days after cell transfer. However, when a magnet was placed near the tumour during the transfer of tumour-specific APS-MNP-loaded CD8⁺ T cells to improve tumour infiltration, a reduced percentage of tumour-specific T cells was found infiltrating the tumour 14 days after cell transfer, which was reflected in a smaller reduction in tumour size compared to tumour-specific CD8⁺ T cells transferred with or without MNPs in the absence of a magnetic field. Nonetheless, magnet placement near the tumour site during cell transfer induced infiltration of activated tumour-specific CD8⁺ T cells in tumour-draining LNs, which remained 14 days after cell transfer.

Conclusions

The use of an EMF to improve targeting of tumour-specific T cells modified with APS-MNPs reduced the percentage of these cells infiltrating the tumour, but promoted the retention and the persistence of these cells in the tumour-draining LNs.

Electronic supplementary material

The online version of this article (10.1186/s12951-019-0520-0) contains supplementary material, which is available to authorized users.

Eomesodermin driven IL-10 production in effector CD8+ T cells promotes a memory phenotype

CD8⁺ T cell differentiation is controlled by the transcription factors T-bet and Eomesodermin, in concert with the cytokines IL-2, IL-10 and IL-12. Among these pathways, the mechanisms by which T-box proteins and IL-10 interact to promote a memory T cell fate remain poorly understood. Here, we show that Eomes and IL-10 drive a central memory phenotype in murine CD8⁺ T cells. Eomes expression led to increased IL-10 expression by the effector CD8⁺ T cells themselves as well as an increase in the level of the lymph node homing selectin CD62L. Furthermore, exposure of effector CD8⁺ T cells to IL-10 maintained CD62L expression levels in culture. Thus, Eomes promotes a step-wise transition of effector T cells towards a memory phenotype, synergizing with IL-10 to enhance the expression of CD62L. The early augmentation of lymph node homing markers by Eomes may facilitate the retention of effector T cells in the relatively low inflammatory milieu of the secondary lymphoid organs that promotes central memory development.

CCR4 mediated chemotaxis of regulatory T cells suppress the activation of T cells and NK cells via TGF-β pathway in human non-small cell lung cancer

C-C chemokine receptor type 4 has been reported to correlate with lung cancer. However, the role of CCR4 in human non-small cell lung cancer patients is not well defined. Here, we demonstrated that increased expression of CCR4 was associated with clinical stage and CCR4 was an independent risk factor for overall survival in NSCLC patients. Moreover, tumor-infiltrating Treg cells were higher expression than matched adjacent tissues in CCR4+ NSCLC. Higher expression of chemokine CCL17 and CCL22 could recruit Treg cells to tumor sites in NSCLC. Treg in TIL exhibit a higher level of suppressive activity on effector T cells than matched adjacent tissues in NSCLC patients. Significant NK cell reduction was observed in tumor regions compared to non-tumor regions. NK cells demonstrated that reduced the killing capacity against target cells and the expression of CD69 ⁺ in vitro. The addition of Treg cells from NSCLC patients efficiently inhibited the anti-tumor ability of autologous NK cells. Treatment with anti-TGF-β antibody restored the impaired cytotoxic activity of T cells and NK cells from tumor tissues. Our results indicate that TGF-β plays an important role in impaired Teff cells and NK cells. It will therefore be valuable to develop therapeutic strategies against CCR4 and TGF-β pathway for therapy of NSCLC.

Dual destructive and protective roles of adaptive immunity in neurodegenerative disorders

Inappropriate T cell responses in the central nervous system (CNS) affect the pathogenesis of a broad range of neuroinflammatory and neurodegenerative disorders that include, but are not limited to, multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer’s disease and Parkinson’s disease. On the one hand immune responses can exacerbate neurotoxic responses; while on the other hand, they can lead to neuroprotective outcomes. The temporal and spatial mechanisms by which these immune responses occur and are regulated in the setting of active disease have gained significant recent attention. Spatially, immune responses that affect neurodegeneration may occur within or outside the CNS. Migration of antigen-specific CD4+ T cells from the periphery to the CNS and consequent immune cell interactions with resident glial cells affect neuroinflammation and neuronal survival. The destructive or protective mechanisms of these interactions are linked to the relative numerical and functional dominance of effector or regulatory T cells. Temporally, immune responses at disease onset or during progression may exhibit a differential balance of immune responses in the periphery and within the CNS. Immune responses with predominate T cell subtypes may differentially manifest migratory, regulatory and effector functions when triggered by endogenous misfolded and aggregated proteins and cell-specific stimuli. The final result is altered glial and neuronal behaviors that influence the disease course. Thus, discovery of neurodestructive and neuroprotective immune mechanisms will permit potential new therapeutic pathways that affect neuronal survival and slow disease progression.