Double negative T cells mediate Lag3-dependent antigen-specific protection in allergic asthma

Canine peripheral non-conventional TCRαβ+ CD4-CD8α- double-negative T cells show T helper 2-like and regulatory properties

The dog is an important companion animal and also serves as model species for human diseases. Given the central role of T cells in immune responses, a basic understanding of canine conventional T cell receptor (TCR)αβ+ T cells, comprising CD4+ single-positive (sp) T helper (Th) and CD8α+ sp cytotoxic T cell subsets, is available. However, characterization of canine non-conventional TCRαβ+ CD4+CD8α+ double-positive (dp) and TCRαβ+ CD4-CD8α- double-negative (dn) T cells is limited. In this study, we performed a comprehensive analysis of canine dp and dn T cells in comparison with their conventional counterparts. TCRαβ+ T cells from peripheral blood of healthy dogs were sorted according to their CD4/CD8α phenotype into four populations (i.e. CD4+ sp, CD8α+ sp, dp, and dn) and selected surface markers, transcription factors and effector molecules were analyzed ex vivo and after in vitro stimulation by RT-qPCR. Novel characteristics of canine dp T cells were identified, expanding the previously characterized Th1-like phenotype to Th17-like and Th2-like properties. Overall, mRNA expression of various Th cell-associated cytokines (i.e. IFNG, IL17A, IL4, IL13) in dp T cells upon stimulation highlights their versatile immunological potential. Furthermore, we demonstrated that the CD4-CD8α- dn phenotype is stable during in vitro stimulation. Strikingly, dn T cells were found to express highest mRNA levels of type 2 effector cytokines (IL4, IL5, and IL13) upon stimulation. Their strong ability to produce IL-4 was confirmed at the protein level. Upon stimulation, the percentage of IL-4-producing cells was even higher in the non-conventional dn than in the conventional CD4+ sp population. Constitutive transcription of IL1RL1 (encoding IL-33Rα) further supports Th2-like properties within the dn T cell population. These data point to a role of dn T cells in type 2 immunity. In addition, the high potential of dn T cells to transcribe the gene encoding the co-inhibitory receptor CTLA-4 and to produce the inhibitory cytokine IL-10 indicates putative immunosuppressive capacity of this population. In summary, this study reveals important novel aspects of canine non-conventional T cells providing the basis for further studies on their effector and/or regulatory functions to elucidate their role in health and disease.

Gingival-derived mesenchymal stem cells alleviate allergic asthma inflammation via HGF in animal models

Allergic asthma is a chronic non-communicable disease characterized by lung tissue inflammation. Current treatments can alleviate the clinical symptoms to some extent, but there is still no cure. Recently, the transplantation of mesenchymal stem cells (MSCs) has emerged as a potential approach for treating allergic asthma. Gingival-derived mesenchymal stem cells (GMSCs), a type of MSC recently studied, have shown significant therapeutic effects in various experimental models of autoimmune diseases. However, their application in allergic diseases has yet to be fully elucidated. In this study, using an OVA-induced allergic asthma model, we demonstrated that GMSCs decrease CD11b+CD11c+ proinflammatory dendritic cells (DCs), reduce Th2 cells differentiation, and thus effectively diminish eosinophils infiltration. We also identified that the core functional factor, hepatocyte growth factor (HGF) secreted by GMSCs, mediated its effects in relieving airway inflammation. Taken together, our findings indicate GMSCs as a potential therapy for allergic asthma and other related diseases.

Immune profiling analysis of double-negative T cells in patients with systemic sclerosis

OBJECTIVE

To construct a molecular immune map of patients with systemic sclerosis (SSc) by mass flow cytometry, and compare the number and molecular expression of double-negative T (DNT) cell subsets between patients and healthy controls (HC).

METHODS

Peripheral blood mononuclear cells (PBMCs) were extracted from the peripheral blood of 17 SSc patients and 9 HC. A 42-channel panel was set up to perform mass cytometry by time of flight (CyTOF) analysis for DNT subgroups. Flow cytometry was used to validate subpopulation functions. The clinical data of patients were collected for correlation analysis.

RESULTS

Compared with HC, the number of total DNT cells decreased in SSc patients. Six DNT subsets were obtained from CyTOF analysis, in which the proportion of cluster1 increased, while the proportion of cluster3 decreased. Further analysis revealed that cluster1 was characterized by high expression of CD28 and CCR7, and cluster3 was characterized by high expression of CD28 and CCR5. After in vitro stimulation, cluster1 secreted more IL-4 and cluster3 secreted more IL-10 in SSc patients compared to HC. Clinical correlation analysis suggested that cluster1 may play a pathogenic role while cluster3 may play a protective role in SSc. ROC curve analysis further revealed that cluster3 may be a potential indicator for determining disease activity in SSc patients.

CONCLUSION

We found a new CCR5+CD28+ DNT cell subset, which played a protective role in the pathogenesis of SSc. Key Points • The number of DNT cells decreased in SSc patients' peripheral blood. • DNT cells do not infiltrate in the skin but secrete cytokines to participate in the pathogenesis of SSc. • A CCR5+CD28+ DNT cell population may play a protective role in SSc.

Double-negative T cells ameliorate psoriasis by selectively inhibiting IL-17A-producing γδlow T cells

BACKGROUND

Psoriasis is a chronic immune-mediated skin condition. Although biologic treatments are effective in controlling psoriasis, some patients do not respond or lose response to these therapies. Thus, new strategies for psoriasis treatment are still urgently needed. Double-negative T cells (DNT) play a significant immunoregulatory role in autoimmune diseases. In this study, we aimed to evaluate the protective effect of DNT in psoriasis and explore the underlying mechanism.

METHODS

We conducted a single adoptive transfer of DNT into an imiquimod (IMQ)-induced psoriasis mouse model through tail vein injection. The skin inflammation and IL-17A producing γδ T cells were evaluated.

RESULTS

DNT administration significantly reduced the inflammatory response in mouse skin, characterized by decreased skin folds, scales, and red patches. After DNT treatment, the secretion of IL-17A by RORc+ γδlow T cells in the skin was selectively suppressed, resulting in an amelioration of skin inflammation. Transcriptomic data suggested heightened expression of NKG2D ligands in γδlow T cells within the mouse model of psoriasis induced by IMQ. When blocking the NKG2D ligand and NKG2D (expressed by DNT) interaction, the cytotoxic efficacy of DNT against RORc+IL17A+ γδlow T cells was attenuated. Using Ccr5-/- DNT for treatment yielded evidence that DNT migrates into inflamed skin tissue and fails to protect IMQ-induced skin lesions.

CONCLUSIONS

DNT could migrate to inflamed skin tissue through CCR5, selectively inhibit IL-17-producing γδlow T cells and finally ameliorate mouse psoriasis. Our study provides feasibility for using immune cell therapy for the prevention and treatment of psoriasis in the clinic.

Enhancing Dendritic Cell Activation Through Manganese-Coated Nanovaccine Targeting the cGAS-STING Pathway

Background

Nanovaccines have emerged as a promising vaccination strategy, exhibiting their capacity to deliver antigens and adjuvants to elicit specific immune responses. Despite this potential, optimizing the design and delivery of nanovaccines remains a challenge.

Methods

In this study, we engineered a dendritic mesoporous silica-based nanocarrier enveloped in a metal-phenolic network (MPN) layer containing divalent manganese ions and tannic acid (MSN@MT). This nanocarrier was tailored for antigen loading to serve as a nanovaccine, aiming to activate the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway in dendritic cells (DCs). Our experimental approach encompassed both cellular assays and mouse immunizations, allowing a comprehensive evaluation of the nanovaccine's impact on DC activation and its influence on the generation of antigen-specific T-cell responses.

Results

MSN@MT demonstrated a remarkable enhancement in humoral and cellular immune responses in mice compared to control groups. This highlights the potential of MSN@MT to effectively trigger the cGAS-STING pathway in DCs, resulting in robust immune responses.

Conclusion

Our study introduces MSN@MT, a unique nanocarrier incorporating divalent manganese ions and tannic acid, showcasing its exceptional ability to amplify immune responses by activating the cGAS-STING pathway in DCs. This innovation signifies a stride in refining nanovaccine design for potent immune activation.

Effects of 101BHG-D01, a novel M receptor antagonism, on allergic rhinitis in animal models and its mechanism

Allergic rhinitis (AR) is a nasal mucosal disease with sneezing and nasal itching as the main symptoms. Although AR treatment continues to improve, there remains a lack of effective drugs. There are still controversies regarding whether anticholinergic drugs can effectively and safely relieve the symptoms of AR and reduce inflammation in the nasal mucosa. Here, we synthesized 101BHG-D01, which is a novel anticholinergic drug that mainly targets the M3 receptor and may reduce the adverse effects of other anticholinergic drugs on the heart. We evaluated the effects of 101BHG-D01 on AR and investigated the potential molecular mechanism of anticholinergic therapy for AR. We found that 101BHG-D01 effectively alleviated AR symptoms, reduced the infiltration of inflammatory cells and attenuated the expression of inflammatory factors (IL-4, IL-5, IL-13, etc.) in various AR animal models. In addition, 101BHG-D01 reduced the activation of mast cells and the release of histamine from rat peritoneal mesothelial cells (RPMCs) challenged by IgE. Moreover, 101BHG-D01 reduced the expression of MUC5AC in IL-13-challenged rat nasal epithelial cells (RNECs) and human nasal epithelial cells (HNEpCs). Furthermore, IL-13 stimulation significantly increased JAK1 and STAT6 phosphorylation, which was suppressed by 101BHG-D01. We demonstrated that 101BHG-D01 reduced mucus secretion and inflammatory cell infiltration in the nasal mucosa, which may occur through a reduction in activation of the JAK1-STAT6 signaling pathway, indicating that 101BHG-D01 is a potent and safe anticholinergic therapy for AR.

Construction and validation of a novel IGFBP3-related signature to predict prognosis and therapeutic decision making for Hepatocellular Carcinoma

Background

IGFBP3 plays a pivotal role in carcinogenesis by being anomalously expressed in some malignancies. However, the clinical value of IGFBP3 and the role of IGFBP3-related signature in HCC remain unclear.

Methods

Multiple bioinformatics methods were used to determine the expression and diagnostic values of IGFBP3. The expression level of IGFBP3 was validated by RT-qPCR and IHC. A IGFBP3-related risk score (IGRS) was built via correlation analysis and LASSO Cox regression analysis. Further analyses, including functional enrichment, immune status of risk groups were analyzed, and the role of IGRS in guiding clinical treatment was also evaluated.

Results

IGFBP3 expression was significantly downregulated in HCC. IGFBP3 expression correlated with multiple clinicopathological characteristics and demonstrated a powerful diagnostic capability for HCC. In addition, a novel IGRS signature was developed in TCGA, which exhibited good performance for prognosis prediction and its role was further validated in GSE14520. In TCGA and GSE14520, Cox analysis also confirmed that the IGRS could serve as an independent prognostic factor for HCC. Moreover, a nomogram with good accuracy for predicting the survival of HCC was further formulated. Additionally, enrichment analysis showed that the high-IGRS group was enriched in cancer-related pathways and immune-related pathways. Additionally, patients with high IGRS exhibited an immunosuppressive phenotype. Therefore, patients with low IGRS scores may benefit from immunotherapy.

Conclusions

IGFBP3 can act as a new diagnostic factor for HCC. IGRS signature represents a valuable predictive tool in the prognosis prediction and therapeutic decision making for Hepatocellular Carcinoma.

IL-33 promotes double negative T cell survival via the NF-κB pathway

IL-33, which is a crucial modulator of adaptive immune responses far beyond type 2 response, can enhance the function of several T cell subsets and maintain the immune homeostasis. However, the contribution of IL-33 to double negative T (DNT) cell remains unappreciated. Here, we demonstrated that the IL-33 receptor ST2 was expressed on DNT cells, and that IL-33 stimulation increased DNT cells proliferation and survival in vivo and in vitro. Transcriptome sequencing analysis also demonstrated that IL-33 enhanced the biological function of DNT cells, especially effects on proliferation and survival. IL-33 promoted DNT cells survival by regulating Bcl-2, Bcl-xl and Survivin expression. IL-33-TRAF4/6-NF-κB axis activation promoted the transmission of essential division and survival signals in DNT cells. However, IL-33 failed to enhance the expression of immunoregulatory molecules in DNT cells. DNT cells therapy combined with IL-33 inhibited T cells survival and further ameliorated ConA-induced liver injury, which mainly depended on the proliferative effect of IL-33 on DNT cells in vivo. Finally, we stimulated human DNT cells with IL-33, and similar results were observed. In conclusion, we revealed a cell intrinsic role of IL-33 in the regulation of DNT cells, thereby identifying a previously unappreciated pathway supporting the expansion of DNT cells in the immune environment.

TCRαβ+NK1.1-CD4-CD8- double-negative T cells inhibit central and peripheral inflammation and ameliorate ischemic stroke in mice

Background: Excessive immune activation leads to secondary injury and impedes injured brain recovery after ischemic stroke. However, few effective methods are currently used for equilibrating immune balance. CD3⁺NK1.1^-TCRβ⁺CD4^-CD8^- double-negative T (DNT) cells which do not express NK cell surface markers are unique regulatory cells that maintain homeostasis in several immune-related diseases. However, the therapeutic potential and regulatory mechanism of DNT cells in ischemic stroke are still unknown. Methods: Mouse ischemic stroke is induced by occlusion of the distal branches of the middle cerebral artery (dMCAO). DNT cells were adoptively transferred intravenously into ischemic stroke mice. Neural recovery was evaluated by TTC staining and behavioral analysis. Using immunofluorescence, flow cytometry, and RNA sequencing, the immune regulatory function of DNT cells was investigated at different time points post ischemic stroke. Results: Adoptive transfer of DNT cells significantly reduces infarct volume and improves sensorimotor function after ischemic stroke. DNT cells suppress peripheral Trem1⁺ myeloid cell differentiation during the acute phase. Furthermore, they infiltrate the ischemic tissue via CCR5 and equilibrate the local immune balance during the subacute phase. During the chronic phase, DNT cells enhance Treg cell recruitment through CCL5, eventually developing an immune homeostatic milieu for neuronal recovery. Conclusions: DNT cell treatment renders the comprehensive anti-inflammatory roles in specific phases of ischemic stroke. Our study suggests that the adoptive transfer of regulatory DNT cells may be a potential cell-based therapy for ischemic stroke.

Immune checkpoint molecules in prevention and development of asthma

Allergic asthma is a respiratory disease initiated by type-2 immune responses characterized by secretion of alarmins, interleukin-4 (IL-4), IL-5, and IL-13, eosinophilic inflammation, and airway hyperresponsiveness (AHR). Immune checkpoints (ICPs) are inhibitory or stimulatory molecules expressed on different immune cells, tumor cells, or other cell types that regulate immune system activation and maintain immune homeostasis. Compelling evidence indicates a key role for ICPs in both the progression and prevention of asthma. There is also evidence of asthma development or exacerbation in some cancer patients receiving ICP therapy. The aim of this review is to provide an updated overview of ICPs and their roles in asthma pathogenesis, and to assess their implications as therapeutic targets in asthma.

Approaches for development of LAG-3 inhibitors and the promise they hold as anticancer agents

INTRODUCTION

LAG-3 is considered to be the third point of immunological control in relation to clinical trials that address cancer treatment, only behind PD-1 and CTLA-4, due to its role as a suppressor of the immune response and enhancer of differentiation of Treg cells.

AREAS COVERED

The authors focus on emphasizing the strategy of development of LAG-3 inhibitors to develop anticancer therapeutics, especially from the perspective of designing new monoclonal and bispecific antibodies against LAG-3. This article also covers details of patents and clinical trials of LAG-3 inhibitors reported in the literature. In addition, we highlight as future research challenges the design and development of peptides and small molecules as inhibitors of LAG-3 function.

EXPERT OPINION

Three approaches have been used for the development of LAG-3 inhibitors, and they include inhibitory LAG-3 binding peptides and antagonist monoclonal and multispecific antibodies. These approaches include more than 100 clinical trials of 21 molecules that bind to LAG-3 and block its binding to MHC II. However, these approaches do not cover the design and development of peptides and small molecules that could inhibit the function of LAG-3, for which it is necessary to develop new alternatives that cover this gap.

Neutrophil activation and NETosis are the predominant drivers of airway inflammation in an OVA/CFA/LPS induced murine model

Background

Asthma is one of the most common chronic diseases that affects more than 300 million people worldwide. Though most asthma can be well controlled, individuals with severe asthma experience recurrent exacerbations and impose a substantial economic burden on healthcare system. Neutrophil inflammation often occurs in patients with severe asthma who have poor response to glucocorticoids, increasing the difficulty of clinical treatment.

Methods

We established several neutrophil-dominated allergic asthma mouse models, and analyzed the airway hyperresponsiveness, airway inflammation and lung pathological changes. Neutrophil extracellular traps (NETs) formation was analyzed using confocal microscopy and western blot.

Results

We found that the ovalbumin (OVA)/complete Freund’s adjuvant (CFA)/low-dose lipopolysaccharide (LPS)-induced mouse model best recapitulated the complex alterations in the airways of human severe asthmatic patients. We also observed OVA/CFA/LPS-exposed mice produced large quantities of neutrophil extracellular traps (NETs) in lung tissue and bone marrow neutrophils. Furthermore, we found that reducing the production of NETs or increasing the degradation of NETs can reduce airway inflammation and airway hyperresponsiveness.

Conclusion

Our findings identify a novel mouse model of neutrophilic asthma. We have also identified NETs play a significant role in neutrophilic asthma models and contribute to neutrophilic asthma pathogenesis. NETs may serve as a promising therapeutic target for neutrophilic asthma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02209-0.

Combined biological effects and lung proteomics analysis in mice reveal different toxic impacts of electronic cigarette aerosol and combustible cigarette smoke on the respiratory system

Combustible cigarettes produce many toxic substances that have been linked to diseases, such as lung cancer and chronic obstructive pulmonary disease. For those smokers unable or unwilling to quit, electronic cigarettes (e-cigarettes) could be used as an alternative to cigarettes. However, the effects and mechanisms of e-cigarette aerosol (ECA) on respiratory function have not been fully elucidated, and in vivo studies of its safety are limited compared to cigarette smoke (CS). In this article, we chose nicotine levels as dosing references and C57BL/6 mice for a 10-week subchronic inhalation toxicity study. A comprehensive set of toxicological endpoints was used to study the effect of exposure. Both CS (6 mg/kg) and ECA (6 or 12 mg/kg) inhalation had decreased the animal’s lung function and increased levels of inflammation markers, along with pathological changes in the airways and lungs, with ECA displaying a relatively small effect at the same dose. Proteomic analysis of lung tissue showed greater overall protein changes by CS than that of ECA, with more severe inflammatory network perturbations. Compared with ECA, KEGG analysis of CS revealed upregulation of more inflammatory and virus-related pathways. Protein–protein interactions (PPI) showed that both ECA and CS significantly changed ribosome and complement system-related proteins in mouse lung tissue. The results support that e-cigarette aerosol is less harmful to the respiratory system than cigarette smoke at the same dose using this animal model, thus providing additional evidence for the relative safety of e-cigarettes.

Intranasal administration of abatacept enhances IL-35+ and IL-10+ producing Bregs in lung tissues of ovalbumin-sensitized asthmatic mice model

Backgrounds

Treating asthmatic rheumatoid arthritis patients with abatacept has been shown to associate with better control of asthma symptoms. However, the mechanism behind that is not investigated.

Methods

Ovalbumin (OVA)- sensitized BALB/c female mice were treated intranasally (IN) or intraperitoneally (IP) with abatacept 4 hrs before the OVA challenge. The effects of abatacept IN or IP on the lungs and blood levels of Tregs and Bregs and their production of immunosuppressive cytokines, were determined using FACS analysis and ELISA assay.

Results

Treating OVA- sensitized asthmatic mice model with abatacept, IN or IP, reduced lung inflammation. IN treatment with abatacept increased the frequency of IL-35 and IL-10 producing Bregs in the lung tissues to a higher level compared to IP treatment. Moreover, the frequency of lungs LAG3⁺ Tregs was significantly increased following treatment. This was also associated with a reduction in lung tissue and serum IL-17 levels of treated mice.

Conclusions

These results suggest that abatacept by enhancing IL-35⁺IL-10⁺ Bregs and LAG3⁺ Tregs might reverse IL-17 induced lung inflammation during asthma.

Targeting breast cancer with a combination of DNT and LAG3 checkpoint blockage and its mechanism

Introduction

The characteristics of the tumor immune microenvironment (TIME) are closely related to immunotherapy. Breast cancer can benefit from immunotherapy, and its TIME is still unclear.

Methods

We utilized mass cytometry to explore the immune cell heterogeneity in breast cancer. Double‐negative T cells (DNTs) from healthy volunteers (HBs) were enriched in vitro. Flow cytometry was used to detect the cell surface receptors of cancer cells and DNT cells. The correlation between immune checkpoints and the abundance of immune cells or prognosis of breast cancer was analyzed by the TCGA database. The messenger RNA (mRNA) expression of functional genes was performed by quantitative real‐time PCR.

Results

We found that the frequencies of Granzyme B (GZMB)⁺CD8⁺T and GZMB⁺DNT cells in cancer tissues (CA) of breast cancer were lower than those in blood samples of patients (PB), and the frequencies of programmed cell death protein 1 (PD1)⁺CD8⁺T and PD1⁺DNT cells in CA were higher than those in PB. DNTs from HBs had a cytotoxic effect on MDA‐MB‐231. LAG3Ab could upregulate the mRNA expression of interferon gamma and perforin by increasing T‐BET transcription to enhance the cytotoxicity of DNT cells in vitro.

Conclusion

Our study revealed the suppressive status of TIME in breast cancer and supported DNT cells had the potential to be applied as a novel adoptive cell therapy for TNBC either alone or combined with LAG3Ab.

TCRαβ+ CD4-/CD8- "double negative" T cells in health and disease-implications for the kidney

Double negative (DN) T cells, one of the least studied T lymphocyte subgroups, express T cell receptor αβ but lack CD4 and CD8 coreceptors. DN T cells are found in multiple organs including kidney, lung, heart, gastrointestinal tract, liver, genital tract, and central nervous system. DN T cells suppress inflammatory responses in different disease models including experimental acute kidney injury, and significant evidence supports an important role in the pathogenesis of systemic lupus erythematosus. However, little is known about these cells in other kidney diseases. Therefore, it is important to better understand different functions of DN T cells and their signaling pathways as promising therapeutic targets, particularly with the increasing application of T cell-directed therapy in humans. In this review, we aim to summarize studies performed on DN T cells in normal and diseased organs in the setting of different disease models with a focus on kidney.

Trogocytosis and fratricide killing impede MSLN-directed CAR T cell functionality

Successful translation of chimeric antigen receptor (CAR) T cell therapy for the treatment of solid tumors has proved to be troublesome, mainly due to the complex tumor microenvironment promoting T cell dysfunction and antigen heterogeneity. Mesothelin (MSLN) has emerged as an attractive target for CAR T cell therapy of several solid malignancies, including ovarian cancer. To improve clinical response rates with MSLN-CAR T cells, a better understanding of the mechanisms impacting CAR T cell functionality in vitro is crucial. Here, we demonstrated superior cytolytic capacity of CD28-costimulated MSLN-CAR T cells (M28z) relative to 4–1BB-costimulated MSLN-CAR T cells (MBBz). Furthermore, CD28-costimulated MSLN CAR T cells displayed enhanced cytolytic capacity against tumor spheroids with heterogeneous MSLN expression compared to MBBz CAR T cells. In this study, we identified CAR-mediated trogocytosis as a potential impeding factor for successful MSLN-CAR T cell therapy due to fratricide killing and contributing to tumor antigen heterogeneity. Moreover, we link antigen-dependent upregulation of LAG-3 with reduced CAR T cell functionality. Taken together, our study highlights the therapeutic potential and bottlenecks of MSLN-CAR T cells, providing a rationale for combinatorial treatment strategies.

OX40 Expression in Eosinophils Aggravates OVA-Induced Eosinophilic Gastroenteritis

Background & Aims

Eosinophils are the main inflammatory effector cells that damage gastrointestinal tissue in eosinophilic gastrointestinal diseases (EGIDs). Activation of the OX40 pathway aggravates allergic diseases, such as asthma, but it is not clear whether OX40 is expressed in eosinophils to regulate inflammation in EGIDs. In this study, we assessed the expression and effect of OX40 on eosinophils in WT and Ox40^-/- eosinophilic gastroenteritis (EGE) mice.

Methods

Eosinophil infiltration, ovalbumin (OVA)-specific Ig production, OX40 expression and inflammatory factor levels in the intestine and bone marrow (BM) were investigated to evaluate inflammation.

Results

We confirmed that OVA-challenged mice produced high levels of Ox40, Mbp, Ccl11, Il5, Il4, Il13, and Il6 mRNA and a low level of Ifng mRNA in the intestine. Increased eosinophils were observed in intestinal and lymph tissues, accompanied by significantly upregulated OX40 and Type 2 cytokine production in eosinophils of EGE mice. Ox40 deficiency ameliorated OVA-induced inflammation, eosinophil infiltration, and cytokine production in the intestine. Consistently, Ox40^{-/ -} eosinophils exhibited decreased proliferation and proinflammatory function. The stimulation of the agonistic anti-OX40 antibody, OX86, promoted the effect of OX40 on eosinophils. The present study also showed that Ox40 deficiency dampened the Traf2/6-related NF-κB signaling pathway in eosinophils.

Conclusions

OX40 may play a critical role in the progress of OVA-induced EGE by promoting the maturation and function of eosinophils via the Traf2/6-related NF-κB signaling pathway.

Expansion of Double-Negative T Cells in Patients before Liver Transplantation Correlates with Post-Transplant Infections

Liver transplantation (LTx) is currently the only effective therapy for patients with end-stage liver diseases, but post-transplant infection is a key issue for morbidity and mortality. In this study, we found that pre-transplant patients with an expansion of double-negative T (DNT) cells (CD3⁺CD4⁻CD8⁻ T cells) had an increased incidence of infections within the first 6 months after LTx. These DNT cells also negatively correlated with their CD4/CD8 ratio. Compared to patients who had no infections after LTx, these DNT cells expressed more CD25, especially in the memory compartment. The receiver operating characteristic (ROC) analysis showed that the threshold area under the ROC curve of DNT cells which could be used to distinguish LTx patients with post-transplant infections from patients without infections after LTx was 0.8353 (95% CI: 0.6591–1.000). The cut-off for the pre-LTx DNT cell level was 11.35%. Although patients with post-transplant infections had decreased levels of CD4/CD8 T cells, CD8⁺ T cells in these patients were more exhausted, with higher PD-1 expression and lower IFNγ secretion. The increased levels of DNT cells in patients with post-transplant infections were still observed 2 weeks after LTx, with higher proportions of memory DNT cells. In conclusion, increased levels of DNT cells in pre-LTx patients may be valuable for the prognosis of post-transplant infections, especially within the first 6 months after LTx.

CD3+CD4-CD8- (Double-Negative) T Cells in Inflammation, Immune Disorders and Cancer

The crucial role of CD4⁺ and CD8⁺ T cells in shaping and controlling immune responses during immune disease and cancer development has been well established and used to achieve marked clinical benefits. CD3⁺CD4^-CD8^- double-negative (DN) T cells, although constituting a rare subset of peripheral T cells, are gaining interest for their roles in inflammation, immune disease and cancer. Herein, we comprehensively review the origin, distribution and functions of this unique T cell subgroup. First, we focused on characterizing multifunctional DN T cells in various immune responses. DN regulatory T cells have the capacity to prevent graft-versus-host disease and have therapeutic value for autoimmune disease. T helper-like DN T cells protect against or promote inflammation and virus infection depending on the specific settings and promote certain autoimmune disease. Notably, we clarified the role of DN tumor-infiltrating lymphocytes and outlined the potential for malignant proliferation of DN T cells. Finally, we reviewed the recent advances in the applications of DN T cell-based therapy for cancer. In conclusion, a better understanding of the heterogeneity and functions of DN T cells may help to develop DN T cells as a potential therapeutic tool for inflammation, immune disorders and cancer.

High transfection efficiency and cell viability of immune cells with nanomaterials-based transfection reagent

Gene manipulation in non-adhesive cells, especially lymphocytes, was difficult due to their low efficiency and high toxicity. Electroporation was reported as a highly efficient method for human and mouse lymphocytes. However, this method requires expensive equipment and causes severe cell damage. Here, the authors present a simple and efficient method to deliver siRNA into lymphocytes with high efficiency and cell viability. This nanomaterials-based transfection reagent was simple and cost-effective and can perform multiple transfections, which further increase the overall efficiency. This method should be applicable for many cell lines and can be used to decipher gene functions of lymphocytes.

Double-negative T cells: Setting the stage for disease control or progression

Double-negative (DN) T cells are present at relatively low frequencies in human peripheral blood, and are characterized as expressing the alpha-beta or gamma-delta T-cell receptor (TCR), but not the CD4 nor the CD8 co-receptors. Despite their low frequencies, these cells are potent producers of cytokines and, thus, are key orchestrators of immune responses. DN T cells were initially associated with induction of peripheral immunological tolerance and immunomodulatory activities related to disease prevention. However, other studies demonstrated that these cells can also display effector functions associated with pathology development. This apparent contradiction highlighted the heterogeneity of the DN T-cell population. Here, we review phenotypic and functional characteristics of DN T cells, emphasizing their role in human diseases. The need for developing biomarkers to facilitate the translation of studies from animal models to humans will also be discussed. Finally, we will examine DN T cells as promising therapeutic targets to prevent or inhibit human disease development.

Paeoniflorin ameliorates airway inflammation and immune response in ovalbumin induced asthmatic mice: From oxidative stress to autophagy

BACKGROUND

Asthma characterized by airway remodeling is a multiple pulmonary disease, which is associated with various physiological processes including inflammation reaction, immune response, oxidative stress and autophagy.

PURPOSE

This study aimed to investigate whether these processes are modulated by the total glucosides of Paeonia lactiflora Pall (TGP), and its active compound paeoniflorin (PF) with anti-inflammatory and immune-regulatory effects could alleviate ovalbumin (OVA)-induced mouse asthma.

METHODS

In vivo, models of mouse asthma were established by intraperitoneally with a mixture of OVA and aluminum hydroxide, plus a single nasal injected with OVA to female C57BL/6 mice. The results were observed with PET imaging, TEM, RT-PCR, western blotting. In vitro, CD4⁺ T cells were isolated and detected with flow cytometry.

RESULTS

TGP, either in its crude or processed form, and PF effectively ameliorated lung injury in mice induced by OVA, regulated immune/inflammatory response by inhibiting the release of pro-inflammatory cytokines, thereby decreasing Th2 cell proportion, inhibited oxidative stress by recovering mitochondrial membrane potential and regulating metabolic activity in dose-dependent manner. Moreover, PF could inhibit autophagy by regulating mitochondrial function. In addition, the therapeutic effects of TGP and PF on pulmonary injury in asthmatic mice were not affected by processing.

CONCLUSION

PF may be a valuable agent in ameliorating inflammation and immune response in asthmatic mice, and the possible mechanism involved in this response rang may from oxidative stress to autophagy.

Punicalagin Alleviates Aged Bronchial Asthma by Inhibiting Th2 Differentiation through IL-4/STAT6 and Jagged1/Notch Pathways

OBJECTIVE

To explore the therapeutic effect and mechanism of punicalagin on bronchial asthma in the elderly.

METHODS

Peripheral venous blood was collected from healthy people and elderly patients with bronchial asthma. Peripheral blood mononuclear cells (PBMCs) were isolated and cultured. PBMCs in the patient group were treated with different concentrations (0, 50, 100, and 200 mg/L) of punicalagin (PUN). MTT assay was used to detect cell activity, ELISA was used to detect the levels of IFN-γ, IL-2, IL-4, and IL-5, and Western blotting was used to detect the protein levels of p-STAT6, Jagged1, and GATA3.

RESULT

MTT results showed that 50-200 mg/L PUN had no cytotoxicity to PBMCs within 24 h. ELISA results showed that the levels of IFN-γ and IL-2 in the serum of the patients were significantly lower than those of healthy people, and the levels of IL-4 and IL-5 were significantly higher than those of the healthy people. PUN treatment significantly increased the levels of IFN-γ and IL-2 in the supernatant of PBMCs culture, while significantly decreased the levels of IL-4 and IL-5, and the change was proportional to the concentration of PUN. Western blotting results showed that the levels of p-STAT6, Jagged1, and GATA3 protein in PBMCs of patients were significantly higher than those of the healthy people. PUN treatment could significantly reduce the expression of p-STAT6, Jagged1, and GATA3 protein in PBMCs of patients, and the reduction level was proportional to PUN concentration.

CONCLUSION

PUN can inhibit Th2 differentiation and regulate Th1/Th2 balance by regulating IL-4/STAT6 and Jagged1/Notch pathways to alleviate the progress of bronchial asthma in the elderly.

Eupatilin Suppresses OVA-Induced Asthma by Inhibiting NF-κB and MAPK and Activating Nrf2 Signaling Pathways in Mice

To investigate the effect of eupatilin in asthma treatment, we evaluated its therapeutic effect and related signal transduction in OVA-induced asthmatic mice and LPS-stimulated RAW264.7 cells. The BALF was tested for changes in lung inflammatory cells. Th2 cytokines in the BALF and OVA-IgE in the serum were measured by ELISA. H&E and PAS staining were used to evaluate histopathological changes in mouse lungs. The key proteins NF-κB, MAPK, and Nrf2 in lung tissues were quantitatively analyzed by Western blotting. Finally, we evaluated the effect of eupatilin on cytokines and related protein expression in LPS-stimulated RAW 264.7 cells in vitro. In OVA-induced asthmatic mice, eupatilin reduced the numbers of inflammatory cells, especially neutrophils and eosinophils. Eupatilin also decreased the levels of IL-5, IL-13 in the BALF and OVA-IgE in the serum. Furthermore, eupatilin inhibited the activation of NF-κB and MAPK pathways and increased the expression of Nrf2 in OVA-induced asthmatic mice. In vitro, eupatilin significantly reduced LPS-stimulated NO, IL-6, and ROS production. Additionally, the NF-κB, MAPK, and Nrf2 protein expression in LPS-stimulated RAW264.7 cells was consistent with that in OVA-induced asthmatic lung tissues. In summary, eupatilin attenuated OVA-induced asthma by regulating NF-κB, MAPK, and Nrf2 signaling pathways. These results suggest the utility of eupatilin as an anti-inflammatory drug for asthma treatment.

Type 2 immunity plays an essential role for murine model of allergic contact dermatitis with mixed type 1/type 2 immune response

BACKGROUND

Both human and mouse allergic contact dermatitis (ACD) frequently demonstrates a combined type 1 and type 2 immune response. However, the relative importance of type 2 immunity in this setting has been incompletely understood yet.

OBJECTIVE

To explore an effector function of type 2 immunity in ACD with mixed type 1/type 2 immune response.

METHODS

Gene expression characteristics of contact hypersensitivity (CHS) model was examined by quantitative polymerase chain reaction. Cytokine profile of T cells was analyzed by flow cytometry. The involvement of type 2 immunity was assessed by antibody-mediated cytokine neutralization and cell depletion. The role of specific subset of cutaneous dendritic cells was evaluated using diphtheria toxin-induced cell-depleting mouse strains.

RESULTS

Oxazolone-induced CHS revealed a combination of type 1/type 2 gene expression. The severity of oxazolone-induced CHS was ameliorated by neutralization of IL-4 but not of IFN-γ, indicating that type 2 immunity plays a dominant effector function in this mixed type 1/type 2 model. Mechanistically, type 2 effector immunity was mounted by CD301b+Langeirn- dermal dendritic cells in part through thymic stromal lymphopoietin-interleukin 7 receptor alpha signaling-dependent manner.

CONCLUSION

Our findings suggest the clinical rationale for targeting type 2 immunity as a relevant therapeutic strategy for the mixed immune phenotype of ACD.

The aggravation of allergic airway inflammation with dibutyl phthalate involved in Nrf2-mediated activation of the mast cells

Dibutyl phthalate (DBP)-an organic pollutant-is ubiquitous in the environment. DBP as an immune adjuvant is related to the development of multiple allergic diseases. However, the current research involving DBP-induced pulmonary toxicity remains poorly understood. Therefore, this research aimed to explore the adverse effect and potential mechanism of DBP exposure on the lungs in rats. In our study, ovalbumin was used to build a rat model of allergic airway inflammation to study any harmful effect of DBP exposure on lung tissues. Rats were treated by intragastric administration of DBP (500 mg kg^-1 or 750 mg kg^-1) and/or subcutaneous injection of SFN (4 mg kg^-1). The results of histopathological analysis, cell count, and myeloperoxidase showed that DBP promoted the inflammatory damage of lungs. In the lung tissues, the detection of terminal deoxynucleotidyl transferase dUNT nick end labeling and oxidative stress indices showed that DBP significantly increased the level of apoptosis and oxidative stress. Western blot analysis indicated that DBP raised the expression level of thymic stromal lymphopoietin and reduced the nuclear expression level of nuclear factor-erythroid-2-related factor 2 (Nrf2), which was further verified by quantitative real-time PCR. Meanwhile, DBP treatment markedly up-regulated the inflammatory cytokines such as IL-4 and IL-13, and rat mast cell protease-2, a marker secreted by mast cells (MCs). Conversely, sulforaphane, a Nrf2 inducer, ameliorated the pulmonary damage induced by DBP in the above. Altogether, our data provides a new insight into the impacts of the activation of MCs on the DBP-induced pulmonary toxicity as well as the safety evaluation of DBP.

NKG2D Enhances Double-Negative T Cell Regulation of B Cells

Numerous studies reported a small subpopulation of TCRαβ+CD4-CD8- (double-negative) T cells that exert regulatory functions in the peripheral lymphocyte population. However, the origin of these double-negative T (DNT) cells is controversial. Some researchers reported that DNT cells originated from the thymus, and others argued that these cells are derived from peripheral immune induction. We report a possible mechanism for the induction of nonregulatory CD4+ T cells to become regulatory double-negative T (iDNT) cells in vitro. We found that immature bone marrow dendritic cells (CD86+MHC-II- DCs), rather than mature DCs (CD86+MHC-II+), induced high levels of iDNT cells. The addition of an anti-MHC-II antibody to the CD86+MHC-II+ DC group significantly increased induction. These iDNT cells promoted B cell apoptosis and inhibited B cell proliferation and plasma cell formation. A subgroup of iDNT cells expressed NKG2D. Compared to NKG2D- iDNT cells, NKG2D+ iDNT cells released more granzyme B to enhance B cell regulation. This enhancement may function via NKG2D ligands expressed on B cells following lipopolysaccharide stimulation. These results demonstrate that MHC-II impedes induction, and iDNT cells may be MHC independent. NKG2D expression on iDNT cells enhanced the regulatory function of these cells. Our findings elucidate one possible mechanism of the induction of peripheral immune tolerance and provide a potential treatment for chronic allograft rejection in the future.

Transcriptome landscape of double negative T cells by single-cell RNA sequencing

CD4 and CD8 coreceptor double negative TCRαβ⁺ T (DNT) cells are increasingly being recognized for their critical and diverse roles in the immune system. However, their molecular and functional signatures remain poorly understood and controversial. Moreover, the majority of studies are descriptive because of the relative low frequency of cells and non-standardized definition of this lineage. In this study, we performed single-cell RNA sequencing on 28,835 single immune cells isolated from mixed splenocytes of male C57BL/6 mice using strict fluorescence-activated cell sorting. The data was replicated in a subsequent study. Our analysis revealed five transcriptionally distinct naïve DNT cell clusters, which expressed unique sets of genes and primarily performed T helper, cytotoxic and innate immune functions. Anti-CD3/CD28 activation enhanced their T helper and cytotoxic functions. Moreover, in comparison with CD4⁺, CD8⁺ T cells and NK cells, Ikzf2 was highly expressed by both naïve and activated cytotoxic DNT cells. In conclusion, we provide a map of the heterogeneity in naïve and active DNT cells, addresses the controversy about DNT cells, and provides potential transcription signatures of DNT cells. The landscape approach herein will eventually become more feasible through newer high throughput methods and will enable clustering data to be fed into a systems analysis approach. Thus the approach should become the "backdrop" of similar studies in the myriad murine models of autoimmunity, potentially highlighting the importance of DNT cells and other minor lineage of cells in immune homeostasis. The clear characterization of functional DNT subsets into helper DNT, cytotoxic DNT and innate DNT will help to better understand the intrinsic roles of different functional DNT subsets in the development and progression of autoimmune diseases and transplant rejection, and thereby may facilitate diagnosis and therapy.

Shaping of T Cell Functions by Trogocytosis

Trogocytosis is an active process whereby plasma membrane proteins are transferred from one cell to the other cell in a cell-cell contact-dependent manner. Since the discovery of the intercellular transfer of major histocompatibility complex (MHC) molecules in the 1970s, trogocytosis of MHC molecules between various immune cells has been frequently observed. For instance, antigen-presenting cells (APCs) acquire MHC class I (MHCI) from allografts, tumors, and virally infected cells, and these APCs are subsequently able to prime CD8⁺ T cells without antigen processing via the preformed antigen-MHCI complexes, in a process called cross-dressing. T cells also acquire MHC molecules from APCs or other target cells via the immunological synapse formed at the cell-cell contact area, and this phenomenon impacts T cell activation. Compared with naïve and effector T cells, T regulatory cells have increased trogocytosis activity in order to remove MHC class II and costimulatory molecules from APCs, resulting in the induction of tolerance. Accumulating evidence suggests that trogocytosis shapes T cell functions in cancer, transplantation, and during microbial infections. In this review, we focus on T cell trogocytosis and the related inflammatory diseases.

CD4 derived double negative T cells prevent the development and progression of nonalcoholic steatohepatitis

Hepatic inflammation is the driving force for the development and progression of NASH. Treatment targeting inflammation is believed to be beneficial. In this study, adoptive transfer of CD4+ T cells converted double negative T cells (cDNT) protects mice from diet-induced liver fat accumulation, lobular inflammation and focal necrosis. cDNT selectively suppress liver-infiltrating Th17 cells and proinflammatory M1 macrophages. IL-10 secreted by M2 macrophages decreases the survival and function of cDNT to protect M2 macrophages from cDNT-mediated lysis. NKG2A, a cell inhibitory molecule, contributes to IL-10 induced apoptosis and dampened suppressive function of cDNT. In conclusion, ex vivo-generated cDNT exert potent protection in diet induced obesity, type 2 diabetes and NASH. The improvement of outcome is due to the inhibition on liver inflammatory cells. This study supports the concept and the feasibility of potentially utilizing this autologous immune cell-based therapy for the treatment of NASH.

LAG-3: from molecular functions to clinical applications

To prevent the destruction of tissues owing to excessive and/or inappropriate immune responses, immune cells are under strict check by various regulatory mechanisms at multiple points. Inhibitory coreceptors, including programmed cell death 1 (PD-1) and cytotoxic T lymphocyte antigen 4 (CTLA-4), serve as critical checkpoints in restricting immune responses against self-tissues and tumor cells. Immune checkpoint inhibitors that block PD-1 and CTLA-4 pathways significantly improved the outcomes of patients with diverse cancer types and have revolutionized cancer treatment. However, response rates to such therapies are rather limited, and immune-related adverse events are also observed in a substantial patient population, leading to the urgent need for novel therapeutics with higher efficacy and lower toxicity. In addition to PD-1 and CTLA-4, a variety of stimulatory and inhibitory coreceptors are involved in the regulation of T cell activation. Such coreceptors are listed as potential drug targets, and the competition to develop novel immunotherapies targeting these coreceptors has been very fierce. Among such coreceptors, lymphocyte activation gene-3 (LAG-3) is expected as the foremost target next to PD-1 in the development of cancer therapy, and multiple clinical trials testing the efficacy of LAG-3-targeted therapy are underway. LAG-3 is a type I transmembrane protein with structural similarities to CD4. Accumulating evidence indicates that LAG-3 is an inhibitory coreceptor and plays pivotal roles in autoimmunity, tumor immunity, and anti-infection immunity. In this review, we summarize the current understanding of LAG-3, ranging from its discovery to clinical application.

Biting Off What Can Be Chewed: Trogocytosis in Health, Infection, and Disease

Trogocytosis is part of an emerging, exciting theme of cell-cell interactions both within and between species, and it is relevant to host-pathogen interactions in many different contexts. Trogocytosis is a process in which one cell physically extracts and ingests "bites" of cellular material from another cell. It was first described in eukaryotic microbes, where it was uncovered as a mechanism by which amoebae kill cells. Trogocytosis is potentially a fundamental form of eukaryotic cell-cell interaction, since it also occurs in multicellular organisms, where it has functions in the immune system, in the central nervous system, and during development. There are numerous scenarios in which trogocytosis occurs and an ever-evolving list of functions associated with this process. Many aspects of trogocytosis are relevant to microbial pathogenesis. It was recently discovered that immune cells perform trogocytosis to kill Trichomonas vaginalis parasites. Additionally, through trogocytosis, Entamoeba histolytica acquires and displays human cell membrane proteins, enabling immune evasion. Intracellular bacteria seem to exploit host cell trogocytosis, since they can use it to spread from cell to cell. Thus, a picture is emerging in which trogocytosis plays critical roles in normal physiology, infection, and disease.

DNT Cell-based Immunotherapy: Progress and Applications

Cancer immunotherapy has firmly established a dominant status in recent years. Adoptive cellular immunotherapy (ACI) is the main branch of immunotherapy. Recently, the immune effector cells of ACI, such as T cells, NK cells, and genetically engineered cells, have been used to achieve significant clinical benefits in the treatment of malignant tumors. However, the clinical applications have limitations, including toxicity, unexpectedly low efficiency, high costs and strict technical requirements. More exploration is needed to optimize ACI for cancer patients. CD3+CD4-CD8- double negative T cells (DNTs) have emerged as functional antitumor effector cells, according to the definition of adoptive immunotherapy. They constitute a kind of T cell subset that mediates nontumor antigen-restricted immunity and has important immune regulatory functions. Preclinical experiments showed that DNTs had a dual effect by killing tumor cells and inhibiting graft-versus-host disease. Notably, DNTs can be acquired from healthy donors and expanded in vitro; thus, allogeneic DNTs may be provided as “off-the-shelf” cellular products that can be readily available for direct clinical application. We review the progress and application of DNTs in immunotherapy. DNTs may provide some novel perspectives on cancer immunotherapy.