Preclinical evaluation of therapeutic vaccines for chronic hepatitis B that stimulate antiviral activities of T cells and NKT cells.

Background & Aims: Liver diseases resulting from chronic HBV infection are a significant cause of morbidity and mortality. Vaccines that elicit T-cell responses capable of controlling the virus represent a treatment strategy with potential for long-term effects. Here, we evaluated vaccines that induce the activity of type I natural killer T (NKT) cells to limit viral replication and license stimulation of conventional antiviral T-cells. Methods: Vaccines were prepared by conjugating peptide epitopes to an NKT-cell agonist to promote co-delivery to antigen-presenting cells, encouraging NKT-cell licensing and stimulation of T cells. Activity of the conjugate vaccines was assessed in transgenic mice expressing the complete HBV genome, administered intravenously to maximise access to NKT cell-rich tissues. Results: The vaccines induced only limited antiviral activity in unmanipulated transgenic hosts, likely attributable to NKT-cell activation as T-cell tolerance to viral antigens is strong. However, in a model of chronic hepatitis B involving transfer of naive HBcAg-specific CD8+ T cells into the transgenic mice, which typically results in specific T-cell dysfunction without virus control, vaccines containing the targeted HBcAg epitope induced prolonged antiviral activity because of qualitatively improved T-cell stimulation. In a step towards a clinical product, vaccines were prepared using synthetic long peptides covering clusters of known HLA-binding epitopes and shown to be immunogenic in HLA transgenic mice. Predictions based on HLA distribution suggest a product containing three selected SLP-based vaccines could give >90 % worldwide coverage, with an average of 3.38 epitopes targeted per individual. Conclusions: The novel vaccines described show promise for further clinical development as a treatment for chronic hepatitis B. Impact and Implications: Although there are effective prophylactic vaccines for HBV infection, it is estimated that 350-400 million people worldwide have chronic hepatitis B, putting these individuals at significant risk of life-threatening liver diseases. Therapeutic vaccination aimed at activating or boosting HBV-specific T-cell responses holds potential as a strategy for treating chronic infection, but has so far met with limited success. Here, we show that a glycolipid-peptide conjugate vaccine designed to coordinate activity of type I NKT cells alongside conventional antiviral T cells has antiviral activity in a mouse model of chronic infection. It is anticipated that a product based on a combination of three such conjugates, each prepared using long peptides covering clusters of known HLA-binding epitopes, could be developed further as a treatment for chronic hepatitis B with broad global HLA coverage.

Fusogenic vesicular stomatitis virus combined with natural killer T cell immunotherapy controls metastatic breast cancer.

BACKGROUND: Metastatic breast cancer is a leading cause of cancer death in woman. Current treatment options are often associated with adverse side effects and poor outcomes, demonstrating the need for effective new treatments. Immunotherapies can provide durable outcomes in many cancers; however, limited success has been achieved in metastatic triple negative breast cancer. We tested whether combining different immunotherapies can target metastatic triple negative breast cancer in pre-clinical models. METHODS: Using primary and metastatic 4T1 triple negative mammary carcinoma models, we examined the therapeutic effects of oncolytic vesicular stomatitis virus (VSVΔM51) engineered to express reovirus-derived fusion associated small transmembrane proteins p14 (VSV-p14) or p15 (VSV-p15). These viruses were delivered alone or in combination with natural killer T (NKT) cell activation therapy mediated by adoptive transfer of α-galactosylceramide-loaded dendritic cells. RESULTS: Treatment of primary 4T1 tumors with VSV-p14 or VSV-p15 alone increased immunogenic tumor cell death, attenuated tumor growth, and enhanced immune cell infiltration and activation compared to control oncolytic virus (VSV-GFP) treatments and untreated mice. When combined with NKT cell activation therapy, oncolytic VSV-p14 and VSV-p15 reduced metastatic lung burden to undetectable levels in all mice and generated immune memory as evidenced by enhanced in vitro recall responses (tumor killing and cytokine production) and impaired tumor growth upon rechallenge. CONCLUSION: Combining NKT cell immunotherapy with enhanced oncolytic virotherapy increased anti-tumor immune targeting of lung metastasis and presents a promising treatment strategy for metastatic breast cancer.

Mendelian Randomization and Transcriptomic Analysis Reveal the Protective Role of NKT Cells in Sepsis.

Background: Sepsis is a life-threatening clinical syndrome caused by dysregulated host response to infection. The mechanism underlying sepsis-induced immune dysfunction remains poorly understood. Natural killer T (NKT) cells are cytotoxic lymphocytes that bridge the innate and adaptive immune systems, the role of NKT cells in sepsis is not entirely understood, and NKT cell cluster differences in sepsis remain unexplored. Methods: Mendelian randomization (MR) analyses were first conducted to investigate the causal relationship between side scatter area (SSC-A) on NKT cells and 28-day mortality of septic patients. A prospective and observational study was conducted to validate the relationship between the percentage of NKT cells and 28-day mortality of sepsis. Then, the single-cell RNA sequencing (scRNA-seq) data of peripheral blood mononuclear cells (PBMCs) from healthy controls and septic patients were profiled. Results: MR analyses first revealed the protective roles of NKT cells in the 28-day mortality of sepsis. Then, 115 septic patients were enrolled. NKT percentage was significantly higher in survivors (n = 84) compared to non-survivors (n = 31) (%, 5.00 ± 3.46 vs 2.18 ± 1.93, P < 0.0001). Patients with lower levels of NKT cells exhibited a significantly increased risk of 28-day mortality. According to scRNA-seq analysis, NKT cell clusters exhibited multiple distinctive characteristics, including a distinguishing cluster defined as FOS+NKT cells, which showed a significant decrease in sepsis. Pseudo-time analysis showed that FOS+NKT cells were characterized by upregulated expression of crucial functional genes such as GZMA and CCL4. CellChat revealed that interactions between FOS+NKT cells and adaptive immune cells including B cells and T cells were decreased in sepsis compared to healthy controls. Conclusion: Our findings indicate that NKT cells may protect against sepsis, and their percentage can predict 28-day mortality. Additionally, we discovered a unique FOS+NKT subtype crucial in sepsis immune response, offering novel insights into its immunopathogenesis.

Reference values of lymphocyte subsets from healthy Polish adults.

The flow cytometry method could support physicians' decisions in the diagnosis and treatment monitoring of immunodeficient patients. Most clinical recommendations are focused on the search for alterations in T- and B-lymphocyte subsets, less commonly natural killer (NK) cells and granulocytes. While reference values for clinically meaningful lymphocyte subsets have been published ubiquitously among numerous countries, we have not found significant data for a population of adult Polish habitats; thus we determined reference values for T, B, and NK subsets according to sex and age. The female group showed a higher percentage of lymphocytes (CD45++), T helper lymphocytes with a higher absolute count, as well as CD4/CD8 ratio, marginal zone-like B cells, class-switched B cells, and CD21low B cells than the male group. The male group was found to have elevated percentages of naïve B lymphocytes, transitional B cells, and plasmablasts. A weak positive correlation with age was found among double positive T lymphocytes, natural killer T cells (NKT) lymphocytes, and CD21low B cells. A negative correlation with age for double negative T lymphocytes, marginal zone-like B cells, and plasmablasts was noted. The results indicated the importance of creating distinct reference ranges regarding sex and age concerning immunophenotype.

Natural killer T cells in allergic asthma: implications for the development of novel immunotherapeutical strategies.

Allergic asthma has emerged as a prevalent allergic disease worldwide, affecting most prominently both young individuals and lower-income populations in developing and developed countries. To devise effective and curative immunotherapy, it is crucial to comprehend the intricate nature of this condition, characterized by an immune response imbalance that favors a proinflammatory profile orchestrated by diverse subsets of immune cells. Although the involvement of Natural Killer T (NKT) cells in asthma pathology is frequently implied, their specific contributions to disease onset and progression remain incompletely understood. Given their remarkable ability to modulate the immune response through the rapid secretion of various cytokines, NKT cells represent a promising target for the development of effective immunotherapy against allergic asthma. This review provides a comprehensive summary of the current understanding of NKT cells in the context of allergic asthma, along with novel therapeutic approaches that leverage the functional response of these cells.

Ox-LDL-induced CD80+ macrophages expand pro-atherosclerotic NKT cells via CD1d in atherosclerotic mice and hyperlipidemic patients.

Atherosclerosis is an inflammatory disease of blood vessels involving the immune system. Natural killer T (NKT) cells, as crucial components of the innate and acquired immune systems, play critical roles in the development of atherosclerosis. However, the mechanism and clinical relevance of NKT cells in early atherosclerosis are largely unclear. The study investigated the mechanism influencing NKT cell function in apoE deficiency-induced early atherosclerosis. Our findings demonstrated that there were higher populations of NKT cells and interferon-gamma (IFN-γ)-producing NKT cells in the peripheral blood of patients with hyperlipidemia and in the aorta, blood, spleen, and bone marrow of early atherosclerotic mice compared with the control groups. Moreover, we discovered that the infiltration of CD80+ macrophages and CD1d expression on CD80+ macrophages in atherosclerotic mice climbed remarkably. CD1d expression increased in CD80+ macrophages stimulated by oxidized low-density lipoprotein (ox-LDL) ex vivo and in vitro. Ex vivo coculture of macrophages with NKT cells revealed that ox-LDL-induced CD80+ macrophages presented lipid antigen α-Galcer (alpha-galactosylceramide) to NKT cells via CD1d, enabling NKT cells to express more IFN-γ. Furthermore, a greater proportion of CD1d+ monocytes and CD1d+CD80+ monocytes were found in peripheral blood of hyperlipidemic patients compared with that of healthy donors. Positive correlations were found between CD1d+CD80+ monocytes and NKT cells or IFN-γ+ NKT cells in hyperlipidemic patients. Our findings illustrated that CD80+ macrophages stimulated NKT cells to secrete IFN-γ via CD1d-presenting α-Galcer, which may accelerate the progression of early atherosclerosis. Inhibiting lipid antigen presentation by CD80+ macrophages to NKT cells may be a promising immune target for the treatment of early atherosclerosis.NEW & NOTEWORTHY This work proposed the ox-LDL-CD80+ monocyte/macrophage-CD1d-NKT cell-IFN-γ axis in the progression of atherosclerosis. The proinflammatory IFN-γ+ NKT cells are closely related to CD1d+CD80+ monocytes in hyperlipidemic patients. Inhibiting CD80+ macrophages to present lipid antigens to NKT cells through CD1d blocking may be a new therapeutic target for atherosclerosis.

Innate Type-2 Cytokines: From Immune Regulation to Therapeutic Targets.

The intricate role of innate type-2 cytokines in immune responses is increasingly acknowledged for its dual nature, encompassing both protective and pathogenic dimensions. Ranging from defense against parasitic infections to contributing to inflammatory diseases like asthma, fibrosis, and obesity, these cytokines intricately engage with various innate immune cells. This review meticulously explores the cellular origins of innate type-2 cytokines and their intricate interactions, shedding light on factors that amplify the innate type-2 response, including TSLP, IL-25, and IL-33. Recent advancements in therapeutic strategies, specifically the utilization of biologics targeting pivotal cytokines (IL-4, IL-5, and IL-13), are discussed, offering insights into both challenges and opportunities. Acknowledging the pivotal role of innate type-2 cytokines in orchestrating immune responses positions them as promising therapeutic targets. The evolving landscape of research and development in this field not only propels immunological knowledge forward but also holds the promise of more effective treatments in the future.

Phase 1/2 study of monalizumab plus durvalumab in patients with advanced solid tumors.

BACKGROUND: The combination of monalizumab (anti-NKG2A/CD94) and durvalumab (anti-programmed death ligand-1) may promote antitumor immunity by targeting innate and adaptive immunity. This phase 1/2 study of monalizumab and durvalumab evaluated safety, antitumor activity, and pharmacodynamics in patients with advanced solid tumors. MAIN BODY: Immunotherapy-naïve patients aged ≥18 years with advanced disease, Eastern Cooperative Oncology Group performance status of 0-1, and 1-3 prior lines of systemic therapy in the recurrent/metastatic setting were enrolled. In part 1 (dose escalation), patients received durvalumab 1500 mg every 4 weeks (Q4W) with increasing doses of monalizumab Q2W/Q4W (n=15). Dose expansion in part 1 included patients with cervical cancer (n=15; durvalumab 1500 mg Q4W and monalizumab 750 mg Q2W) or metastatic microsatellite stable (MSS)-colorectal cancer (CRC) (n=15; durvalumab 1500 mg Q4W and monalizumab 750 mg Q4W). In part 2 (dose expansion), patients with MSS-CRC (n=40), non-small cell lung cancer (NSCLC; n=20), MSS-endometrial cancer (n=40), or ovarian cancer (n=40) received durvalumab 1500 mg Q4W and monalizumab 750 mg Q2W. The primary endpoint was safety. Secondary endpoints included antitumor activity per Response Evaluation Criteria In Solid Tumors version 1.1 (RECIST v1.1). Exploratory analyses included assessment of T-cell and natural killer (NK) cell activation and proliferation in peripheral blood and the tumor microenvironment (TME). The study enrolled 185 patients (part 1, 45; part 2, 140). No dose-limiting toxicities were observed and the maximum tolerated dose was not reached. In part 2, the most common treatment-related adverse events were fatigue (12.1%), asthenia (9.3%), diarrhea (9.3%), pruritus (7.9%), and pyrexia (7.1%). In the expansion cohorts, response rates were 0% (cervical), 7.7% (MSS-CRC), 10% (NSCLC), 5.4% (ovarian), and 0% (MSS-endometrial). Sustained NK cell activation, CD8+ T-cell proliferation, increased serum levels of CXCL10 (C-X-C motif chemokine ligand 10) and CXCL11, and increased tumor infiltration of CD8+ and granzyme B+ cells were observed. CONCLUSIONS: Although efficacy was modest, monalizumab plus durvalumab was well tolerated and encouraging immune activation was observed in the peripheral blood and TME. TRIAL REGISTRATION NUMBER: NCT02671435.

PD-1 checkpoint inhibition enhances the antilymphoma activity of CD19-CAR-iNKT cells that retain their ability to prevent alloreactivity.

BACKGROUND: Relapse and graft-versus-host disease (GVHD) are the main causes of death after allogeneic hematopoietic cell transplantation (HCT). Preclinical murine models and clinical data suggest that invariant natural killer T (iNKT) cells prevent acute and chronic GVHD. In addition, iNKT cells are crucial for efficient immune responses against malignancies and contribute to reduced relapse rates after transplantation. Chimeric antigen receptors (CAR) redirect effector cells to cell surface antigens and enhance killing of target cells. With this study, we aimed to combine enhanced cytotoxicity of CD19-CAR-iNKT cells against lymphoma cells with their tolerogenic properties. METHODS: iNKT cells were isolated from peripheral blood mononuclear cells and transduced with an anti-CD19-CAR retrovirus. After in vitro expansion, the functionality of CD19-CAR-iNKT cells was assessed by flow cytometry, image stream analysis and multiplex analysis in single-stimulation or repeated-stimulation assays. Moreover, the immunoregulatory properties of CD19-CAR-iNKT cells were analyzed in apoptosis assays and in mixed lymphocyte reactions. The effect of checkpoint inhibition through nivolumab was analyzed in these settings. RESULTS: In this study, we could show that the cytotoxicity of CD19-CAR-iNKT cells was mediated either through engagement of their CAR or their invariant T-cell receptor, which may circumvent loss of response through antigen escape. However, encounter of CD19-CAR-iNKT cells with their target induced a phenotype of exhaustion. Consequently, checkpoint inhibition increased cytokine release, cytotoxicity and survival of CD19-CAR-iNKT cells. Additionally, they showed robust suppression of alloreactive immune responses. CONCLUSION: In this work, we demonstrate that CAR-iNKT cells are a powerful cytotherapeutic option to prevent or treat relapse while potentially reducing the risk of GVHD after allogeneic HCT.

Single-cell transcriptomics reveal different maturation stages and sublineage commitment of human thymic invariant natural killer T cells.

Invariant natural killer T cells are a rare, heterogeneous T-cell subset with cytotoxic and immunomodulatory properties. During thymic development, murine invariant natural killer T cells go through different maturation stages differentiating into distinct sublineages, namely, invariant natural killer T1, 2, and 17 cells. Recent reports indicate that invariant natural killer T2 cells display immature properties and give rise to other subsets, whereas invariant natural killer T1 cells seem to be terminally differentiated. Whether human invariant natural killer T cells follow a similar differentiation model is still unknown. To define the maturation stages and assess the sublineage commitment of human invariant natural killer T cells during thymic development, in this study, we performed single-cell RNA sequencing analysis on human Vα24+Vß11+ invariant natural killer T cells isolated from thymocytes. We show that these invariant natural killer T cells displayed heterogeneity, and our unsupervised analysis identified 5 clusters representing different maturation stages, from an immature profile with high expression of genes important for invariant natural killer T cell development and proliferation to a mature, fully differentiated profile with high levels of cytotoxic effector molecules. Evaluation of expression of sublineage-defining gene sets revealed mainly cells with an invariant natural killer T2 signature in the most immature cluster, whereas the more differentiated ones displayed an invariant natural killer T1 signature. Combined analysis with a publicly available single-cell RNA sequencing data set of human invariant natural killer T cells from peripheral blood suggested that the 2 main subsets exist both in thymus and in the periphery, while a third more immature one was restricted to the thymus. Our data point to the existence of different maturation stages of human thymic invariant natural killer T cells and provide evidence for sublineage commitment of invariant natural killer T cells in the human thymus.

Contradictory Effect of Lymphocyte Therapy and Prednisolone Therapy on CD3+CD8+CD56+ Natural Killer T Population in Women with Recurrent Spontaneous Abortion.

Background: Natural killer T (NKT) cells are influential immune cells in pregnancy failures, including recurrent spontaneous abortion (RSA). Different approaches are used for these disorders due to their effects on maternal immunomodulation. Aims: In the present study, we compared the effects of two typical immunotherapies (lymphocyte immunotherapy [LIT] and low-dose prednisolone) on CD3+CD56+CD16+ and CD3+CD56+CD8+ cells as two distinct subsets of NKT cells in Women with RSA. Settings and Design: This study was a comparative cohort study conducted from 2021 to 2022. One hundred and five women with RSA were distributed into three treatment groups randomly. Materials and Methods: Fifty women in the group of low-dose prednisolone therapy, fifty women in the LIT group and five women without any treatment as the control group were included in the study. NK and NKT cell subsets were assessed using flow cytometry. Furthermore, the concentration of interferon-gamma (IFN-γ), transforming growth factor-beta (TGF-ß) and interleukin-10 (IL-10) was measured quantitatively using the enzyme-linked immunosorbent assay technique. Statistical Analysis Used: Normality and comparisons between study groups were performed by non-parametric unpaired Mann-Whitney, Kruskal-Wallis rank sum test, and one-way ANOVA. Results: The percentage of CD56dim NK cells was increased after prednisolone therapy, while this population significantly decreased in the LIT group. In contrast to the LIT group, the administration of prednisolone increased CD3+CD8+CD56+ NKT cells (P < 0.0001), which is helpful for pregnancy. The effect of the investigated treatment approaches on the population of peripheral CD3+CD56+CD16+ NKT cells of women with RSA was not adequately significant. The same situation was also observed regarding the serum level of IFN-γ. However, a significant decrease in serum levels of IL-10 and TGF-ß was observed after prednisolone therapy. Conclusion: The lower capability of LIT in changing the population of NKT cells compared to prednisolone therapy may be due to its mechanism of action, which is related to the production of blocking antibodies. These treatment approaches had different effects on NKT cells, indicating that NKT cell population and function can be affected using LIT and prednisolone therapy distinctly. In addition, prednisolone therapy and LIT in women with normal serum levels of IFN-γ have no harmful effects in changing the production of this critical cytokine.

Invariant natural killer T cells in autoimmune cholangiopathies: Mechanistic insights and therapeutic implications.

Invariant natural killer T cells (iNKT cells) constitute a specialized subset of lymphocytes that bridges innate and adaptive immunity through a combination of traits characteristic of both conventional T cells and innate immune cells. iNKT cells are characterized by their invariant T cell receptors and discerning recognition of lipid antigens, which are presented by the non-classical MHC molecule, CD1d. Within the hepatic milieu, iNKT cells hold heightened prominence, contributing significantly to the orchestration of organ homeostasis. Their unique positioning to interact with diverse cellular entities, ranging from epithelial constituents like hepatocytes and cholangiocytes to immunocytes including Kupffer cells, B cells, T cells, and dendritic cells, imparts them with potent immunoregulatory abilities. Emergering knowledge of liver iNKT cells subsets enable to explore their therapeutic potential in autoimmne liver diseases. This comprehensive review navigates the landscape of iNKT cell investigations in immune-mediated cholangiopathies, with a particular focus on primary biliary cholangitis and primary sclerosing cholangitis, across murine models and human subjects to unravel the intricate involvements of iNKT cells in liver autoimmunity. Additionally, we also highlight the prospectives of iNKT cells as therapeutic targets in cholangiopathies. Modulation of the equilibrium between regulatory and proinflammatory iNKT subsets can be defining determinant in the dynamics of hepatic autoimmunity. This discernment not only enriches our foundational comprehension but also lays the groundwork for pioneering strategies to navigate the multifaceted landscape of liver autoimmunity.

Extranodal NK/T-Cell Lymphoma, Nasal Type, Extranasal and Ulcerative Blister Variant, Case Report.

The extranodal natural killer (NK) T-cell lymphoma of nasal type is a form of lymphoma that falls within the WHO/EORTC 2018 classification of cutaneous T-cell lymphomas. It is characterized for being aggressive, infrequent, and destroying midline facial structures; however, it can also be in primary or secondary form at extranasal sites, such as the skin or the gastrointestinal tract, among others. We report the case of an 18-year-old patient with an extranodal NK/T-cell lymphoma located in an extranasal site. The clinical presentation is characterized for being multifocal and with erythematous-violaceous plaques that progress to hemorrhagic blisters and necrotic ulcers. Although this type of lymphoma has been reported previously by others, the presence of blisters is an atypical finding, which we believe has been described only in one case in the medical literature.

Natural Killer T Cell Diversity and Immunotherapy.

Invariant natural killer T cells (iNKTs), a type of unconventional T cells, share features with NK cells and have an invariant T cell receptor (TCR), which recognizes lipid antigens loaded on CD1d molecules, a major histocompatibility complex class I (MHC-I)-like protein. This interaction produces the secretion of a wide array of cytokines by these cells, including interferon gamma (IFN-γ) and interleukin 4 (IL-4), allowing iNKTs to link innate with adaptive responses. Interestingly, molecules that bind CD1d have been identified that enable the modulation of these cells, highlighting their potential pro-inflammatory and immunosuppressive capacities, as required in different clinical settings. In this review, we summarize key features of iNKTs and current understandings of modulatory α-galactosylceramide (α-GalCer) variants, a model iNKT cell activator that can shift the outcome of adaptive immune responses. Furthermore, we discuss advances in the development of strategies that modulate these cells to target pathologies that are considerable healthcare burdens. Finally, we recapitulate findings supporting a role for iNKTs in infectious diseases and tumor immunotherapy.

Natural Killer T (NKT) Cells in Autoimmune Hepatitis: Current Evidence from Basic and Clinical Research.

Natural killer T (NKT) cells are unconventional T cells that are activated by glycolipid antigens. They can produce a variety of inflammatory and regulatory cytokines and, therefore, modulate multiple aspects of the immune response in different pathological settings, including autoimmunity. NKT cells have also been implicated in the immunopathogenesis of autoimmune hepatitis, and in this review we summarize and analyze the main studies investigating the involvement and/or homeostasis of NKT cells in this disease. In detail, the evidence from both basic and clinical research has been specifically analyzed. Even though the experimental murine models supported a relevant role of NKT cells in immune-mediated hepatic injury, very few studies specifically investigated NKT cell homeostasis in patients with autoimmune hepatitis; however, these initial studies reported some alterations of NKT cells in these patients, which may also correlate with the disease activity to some extent. Further clinical studies are needed to investigate the potential role and use of NKT cell analysis as a disease marker of clinical relevance, and to better understand the precise cellular and molecular mechanisms by which NKT cells contribute to the pathogenesis of autoimmune hepatitis.

De novo fatty-acid synthesis protects invariant NKT cells from cell death, thereby promoting their homeostasis and pathogenic roles in airway hyperresponsiveness.

Invariant natural-killer T (iNKT) cells play pathogenic roles in allergic asthma in murine models and possibly also humans. While many studies show that the development and functions of innate and adaptive immune cells depend on their metabolic state, the evidence for this in iNKT cells is very limited. It is also not clear whether such metabolic regulation of iNKT cells could participate in their pathogenic activities in asthma. Here, we showed that acetyl-coA-carboxylase 1 (ACC1)-mediated de novo fatty-acid synthesis is required for the survival of iNKT cells and their deleterious functions in allergic asthma. ACC1, which is a key fatty-acid synthesis enzyme, was highly expressed by lung iNKT cells from WT mice that were developing asthma. Cd4-Cre::Acc1fl/fl mice failed to develop OVA-induced and HDM-induced asthma. Moreover, iNKT cell-deficient mice that were reconstituted with ACC1-deficient iNKT cells failed to develop asthma, unlike when WT iNKT cells were transferred. ACC1 deficiency in iNKT cells associated with reduced expression of fatty acid-binding proteins (FABPs) and peroxisome proliferator-activated receptor (PPAR)γ, but increased glycolytic capacity that promoted iNKT-cell death. Furthermore, circulating iNKT cells from allergic-asthma patients expressed higher ACC1 and PPARG levels than the corresponding cells from non-allergic-asthma patients and healthy individuals. Thus, de novo fatty-acid synthesis prevents iNKT-cell death via an ACC1-FABP-PPARγ axis, which contributes to their homeostasis and their pathogenic roles in allergic asthma.

Invariant natural killer T cells and incidence of first-time coronary events: a nested case-control study.

Aims: Invariant natural killer T (iNKT) cells, a T cell subset that is CD1d-restricted and expresses a semi-invariant T cell receptor, have been proposed to contribute to dyslipidaemia-driven cardiovascular disease due to their ability to specifically recognize lipid antigens. Studies in mice have attributed pro-atherogenic properties to iNKT cells, but studies in humans investigating associations of iNKT cells with incident coronary events (CE) are lacking. Methods and results: Here, we used flow cytometry to enumerate circulating iNKT cells (CD3+ CD1d-PBS57-Tetramer+) in a case-control cohort nested within the prospective population-based Malmö Diet and Cancer Study (n = 416) to explore associations with incident first-time CE during a median follow-up of 14 years. We found a significant inverse association between CD4- and CD8- double negative (DN) iNKT cells and incident CE, with an odds ratio of 0.62 [95% confidence interval (CI) 0.38-0.99; P = 0.046] comparing the highest vs. the lowest tertile of DN iNKT cells. The association remained significant after adjustment for cardiovascular risk factors with an odds ratio of 0.57 (95% CI 0.33-0.99; P = 0.046). In contrast, total iNKT cells were not significantly associated with incident CE after adjustment, with an odds ratio of 0.74 (95% CI 0.43-1.27; P = 0.276). Conclusion: Our findings indicate that animal studies suggesting an atherosclerosis-promoting role for iNKT cells may not translate to human cardiovascular disease as our data show an association between high circulating numbers of DN iNKT cells and decreased risk of incident CE.

Anti-CD1d treatment suppresses immunogenic maturation of lung dendritic cells dependent on lung invariant natural killer T cells in asthmatic mice.

Our previous findings show that invariant natural killer T (iNKT)cells can promote immunogenic maturation of lung dendritic cells (LDCs) to enhance Th2 cell responses in asthma. It has been accepted that recognition of glycolipid antigens presented by CD1d molecules by the T cell receptors of iNKT cells leads to iNKT cell activation. Therefore, we examine the immunoregulatory influences of anti-CD1d treatment on Th2 cell response and immunogenic maturation of LDCs and subsequently explored whether these influences were dependent on lung iNKT cells in asthmatic mice. We discoveredthat in wild-type mice sensitized and challenged with house dust mite or ovalbumin (OVA), anti-CD1d treatment inhibited Th2 cell response and immunogenic maturation of LDCs. LDCs from asthmatic mice with anti-CD1d treatment had a markedly decreased influence on Th2 cell responses in vivo and in vitro. Furthermore, anti-CD1d treatment reduced the abundance and activation of lung iNKT cells in asthmatic mice. Moreover, in asthmatic iNKT cell-deficient Jα18-/- mice, anti-CD1d treatment did not influence Th2 cell responses and immunogenic maturation of LDCs. Meanwhile, the quantity of CD40L+ iNKT cells in asthmatic mice was significant decreased by anti-CD1d treatment. Finally, the inhibition of anti-CD1d treatment on LDC immunogenic maturation and Th2 cell responses in asthmatic mice was reversed by anti-CD40 treatment. Our data suggest that anti-CD1d treatment can suppress Th2 cell responses through inhibiting immunogenic maturation of LDCs dependent on lung iNKT cells, which couldbe partially related to the downregulation of CD40L expression on lung iNKT cells in asthmatic mice.

Increased ILT2+ natural killer T cells correlate with disease activity in systemic lupus erythematosus.

OBJECTIVE: Numerous immune cell types, such as B and T lymphocytes, natural killer cells (NK), and NKT cells, are related to the pathogenesis of diseases in systemic lupus erythematosus (SLE). Our goal in this investigation is to examine the phenotype of NK cells and NKT cells alterations in individuals with SLE. METHODS: Typically, 50 SLE patients and 24 age-matched healthy people had their PBMCs obtained. Employing flow cytometry, the phenotype of NK and NKT cells and immunoglobulin-like transcript 2 (ILT2) expressions were identified. ELISA was utilized to evaluate the amounts of interleukin-15 (IL-15) and sHLA-G in the serum. RESULTS: The frequencies of the circulating NK and NKT cells in individuals with SLE were decreased compared to healthy controls. Furthermore, ILT2 expression was significantly increased in NKT cells, but showed no obvious change in NK cells. Clinical severity and active nephritis were substantially associated with ILT2+ NKT cell frequencies. The correlation study showed that the upregulation of ILT2 expression was related to sHLA-G in plasma but not to IL-15. CONCLUSIONS: ILT2+ NKT cells have a vital function in the immune abnormalities of SLE, which can also supply a viable goal for therapeutic intervention. Key Points •ILT2 expression was significantly increased in NKT cells in SLE patients. •ILT2+ NKT cell frequencies were associated with clinical severity which may be used as an indicator for evaluating disease activity in patients with SLE.