Thymic development of unconventional T cells: how NKT cells, MAIT cells and γδ T cells emerge

Identification of α-galactosylceramide as an endogenous mammalian antigen for iNKT cells

Invariant natural killer T (iNKT) cells are unconventional T cells recognizing lipid antigens in a CD1d-restricted manner. Among these lipid antigens, α-galactosylceramide (α-GalCer), which was originally identified in marine sponges, is the most potent antigen. Although the presence of α-anomeric hexosylceramide and microbiota-derived branched α-GalCer is reported, antigenic α-GalCer has not been identified in mammals. Here, we developed a high-resolution separation and detection system, supercritical fluid chromatography tandem mass spectrometry (SFC/MS/MS), that can discriminate hexosylceramide diastereomers (α-GalCer, α-GlcCer, β-GalCer, or β-GlcCer). The B16 melanoma tumor cell line does not activate iNKT cells; however, ectopic expression of CD1d was sufficient to activate iNKT cells without adding antigens. B16 melanoma was unlikely to generate iNKT cell antigens; instead, antigen activity was detected in cell culture serum. Activity-based purification and SFC/MS/MS identified dihydrosphingosine-based saturated α-GalCer as an antigenic component in serum, bile, and lymphoid tissues. These results show the first evidence for the presence of potent antigenic α-GalCer in mammals.

Innate immune cells link dietary cues to normal and abnormal metabolic regulation

A slew of common metabolic disorders, including type 2 diabetes, metabolic dysfunction-associated steatotic liver disease and steatohepatitis, are exponentially increasing in our sedentary and overfed society. While macronutrients directly impact metabolism and bioenergetics, new evidence implicates immune cells as critical sensors of nutritional cues and important regulators of metabolic homeostasis. A deeper interrogation of the intricate and multipartite interactions between dietary components, immune cells and metabolically active tissues is needed for a better understanding of metabolic regulation and development of new treatments for common metabolic diseases. Responding to macronutrients and micronutrients, immune cells play pivotal roles in interorgan communication between the microbiota, small intestine, metabolically active cells including hepatocytes and adipocytes, and the brain, which controls feeding behavior and energy expenditure. This Review focuses on the response of myeloid cells and innate lymphocytes to dietary cues, their cross-regulatory interactions and roles in normal and aberrant metabolic control.

Selective regulation of IFN-γ and IL-4 co-producing unconventional T cells by purinergic signaling

Unconventional T cells, including mucosal-associated invariant T (MAIT), natural killer T (NKT), and gamma-delta T (γδT) cells, comprise distinct T-bet+, IFN-γ+ and RORγt+, IL-17+ subsets which play differential roles in health and disease. NKT1 cells are susceptible to ARTC2-mediated P2X7 receptor (P2RX7) activation, but the effects on other unconventional T-cell types are unknown. Here, we show that MAIT, γδT, and NKT cells express P2RX7 and are sensitive to P2RX7-mediated cell death. Mouse peripheral T-bet+ MAIT1, γδT1, and NKT1 cells, especially in liver, co-express ARTC2 and P2RX7. These markers could be further upregulated upon exposure to retinoic acid. Blocking ARTC2 or inhibiting P2RX7 protected MAIT1, γδT1, and NKT1 cells from cell death, enhanced their survival in vivo, and increased the number of IFN-γ-secreting cells without affecting IL-17 production. Importantly, this revealed the existence of IFN-γ and IL-4 co-producing unconventional T-cell populations normally lost upon isolation due to ARTC2/P2RX7-induced death. Administering extracellular NAD in vivo activated this pathway, depleting P2RX7-sensitive unconventional T cells. Our study reveals ARTC2/P2RX7 as a common regulatory axis modulating the unconventional T-cell compartment, affecting the viability of IFN-γ- and IL-4-producing T cells, offering important insights to facilitate future studies into how these cells can be regulated in health and disease.

ThymoSpheres culture: A model to study human polyclonal unconventional T cells

In vitro cultures remain crucial for studying the fundamental mechanisms of human T-cell development. Here, we introduce a novel in vitro cultivation system based on ThymoSpheres (TS): dense spheroids consisting of DLL4-expressing stromal cells and human hematopoietic precursor cells, in the absence of thymic epithelial cells. These spheroids are subsequently cultured at the air-liquid interphase. TS generate large numbers of mature T cells, are easy to manipulate, scalable, and can be repeatably sampled to monitor T-cell differentiation. The mature T cells generated from primary human hematopoietic precursor cells were extensively characterized using single-cell RNA and combined T-cell receptor (TCR) sequencing. These predominantly CD8α T cells exhibit transcriptional and TCR CDR3 characteristics similar to the recently described human polyclonal αβ unconventional T cell (UTC) lineage. This includes the expression of hallmark genes associated with agonist selection, such as IKZF2 (Helios), and the expression of various natural killer receptors. The TCR repertoire of these UTCs is polyclonal and enriched for CDR3-associated autoreactive features and early rearrangements of the TCR-α chain. In conclusion, TS cultures offer an intriguing platform to study the development of this human polyclonal UTC lineage and its inducing selection mechanisms.

Immune checkpoint landscape of human atherosclerosis and influence of cardiometabolic factors

Immune checkpoint inhibitor (ICI) therapies can increase the risk of cardiovascular events in survivors of cancer by worsening atherosclerosis. Here we map the expression of immune checkpoints (ICs) within human carotid and coronary atherosclerotic plaques, revealing a network of immune cell interactions that ICI treatments can unintentionally target in arteries. We identify a population of mature, regulatory CCR7+FSCN1+ dendritic cells, similar to those described in tumors, as a hub of IC-mediated signaling within plaques. Additionally, we show that type 2 diabetes and lipid-lowering therapies alter immune cell interactions through PD-1, CTLA4, LAG3 and other IC targets in clinical development, impacting plaque inflammation. This comprehensive map of the IC interactome in healthy and cardiometabolic disease states provides a framework for understanding the potential adverse and beneficial impacts of approved and investigational ICIs on atherosclerosis, setting the stage for designing ICI strategies that minimize cardiovascular disease risk in cancer survivors.

Developmental trajectory of unconventional T cells of the cynomolgus macaque thymus

As nonhuman primates are immunologically the closest model to humans, a comprehensive understanding of T-cell development in these species is crucial. However, the differentiation pathways in which thymocytes participate, along with their heterogeneity, remain poorly characterized. Using single-cell RNA sequencing, we thoroughly profiled the development of various T-cell lineages in the juvenile cynomolgus monkey thymus, identifying and characterizing 12 distinct thymic cell states or types. Interestingly, we identified two unexpected cell types, an agonist-selected and a memory-like cell population. The agonist-selected cell population expressed genes associated with strong TCR signaling, such as PDCD1, CD5, NFKBID, NFATC1, BCL2L11, and NR4A1 but exhibiting significantly higher PDCD1 expression compared with cells following the conventional developmental pathway. Additionally, we identified a substantial number of memory-like cell populations characterized by high CXCR3 and EOMES expression. Notably, this population also highly expressed the effector-associated markers, GZMK, NKG7, and GNLY, as well as the innate cell-associated markers, ZBTB16, TYROBP, KLRB1, KLRC1, and NCR3. The EOMES + memory-like cell population expressed highly PDCD1, indicating the presence of an agonist-selection footprint. Our findings provide insights into the agonist-selection pathway that allows self-reactive thymocytes to survive thymic selections and differentiate into various unconventional T-cell lineages.

Peripheral blood MR1 tetramer-positive mucosal-associated invariant T-cell function is modulated by mammalian target of rapamycin complex 1 in patients with active tuberculosis

Tuberculosis (TB) is still an urgent global public health problem. Notably, mucosal-associated invariant T (MAIT) cells play an important role in early anti-TB immune response. Targeted control of them may be an effective method to improve vaccine efficacy and TB treatment. However, the biology and signal regulation mechanisms of MAIT cells in TB patients are still poorly understood. Previous studies have been limited by the lack of reagents to specifically identify MAIT cells. In addition, the use of alternative markers may subsume non-MAIT cell into MAIT cell populations. In this study, the human MR1 tetramer which can specifically identify MAIT cells was used to further explore the effect and mechanism of MAIT cells in anti-TB immune response. Our results showed that the tetramer+ MAIT cells in peripheral blood of TB patients were mainly CD8+ or CD4-CD8- cells, and very few were CD4+ cells. After BCG infecting autologous antigen-presenting cells, MAIT cells in patients produced significantly higher levels of cytokines, lysis and proliferation compared with healthy controls. After suppression of mTORC1 by the mTORC1-specific inhibitor rapamycin, the immune response of MAIT cells in patients was significantly reduced. This study demonstrates that peripheral blood tetramer+ MAIT cells from TB patients have significant anti-TB immune effect, which is regulated by mTORC1. This could provide ideas and potential therapeutic targets for the development of novel anti-TB immunotherapy.

Development of Ribityllumazine Analogue as Mucosal-Associated Invariant T Cell Ligands

Mucosal-associated invariant T (MAIT) cells are a subset of innate-like T cells abundant in human tissues that play a significant role in defense against bacterial and viral infections and in tissue repair. MAIT cells are activated by recognizing microbial-derived small-molecule ligands presented by the MHC class I related-1 protein. Although several MAIT cell modulators have been identified in the past decade, potent and chemically stable ligands remain limited. Herein, we carried out a structure-activity relationship study of ribityllumazine derivatives and found a chemically stable MAIT cell ligand with a pteridine core and a 2-oxopropyl group as the Lys-reactive group. The ligand showed high potency in a cocultivation assay using model cell lines of antigen-presenting cells and MAIT cells. The X-ray crystallographic analysis revealed the binding mode of the ligand to MR1 and the T cell receptor, indicating that it forms a covalent bond with MR1 via Schiff base formation. Furthermore, we found that the ligand stimulated proliferation of human MAIT cells in human peripheral blood mononuclear cells and showed an adjuvant effect in mice. Our developed ligand is one of the most potent among chemically stable MAIT cell ligands, contributing to accelerating therapeutic applications of MAIT cells.

Direct recognition of an intact foreign protein by an αβ T cell receptor

αβ T cell receptors (αβTCRs) co-recognise antigens when bound to Major Histocompatibility Complex (MHC) or MHC class I-like molecules. Additionally, some αβTCRs can bind non-MHC molecules, but how much intact antigen reactivities are achieved remains unknown. Here, we identify an αβ T cell clone that directly recognises the intact foreign protein, R-phycoerythrin (PE), a multimeric (αβ)6γ protein complex. This direct αβTCR-PE interaction occurs in an MHC-independent manner, yet triggers T cell activation and bound PE with an affinity comparable to αβTCR-peptide-MHC interactions. The crystal structure reveals how six αβTCR molecules simultaneously engage the PE hexamer, mediated by the complementarity-determining regions (CDRs) of the αβTCR. Here, the αβTCR mainly binds to two α-helices of the globin fold in the PE α-subunit, which is analogous to the antigen-binding platform of the MHC molecule. Using retrogenic mice expressing this TCR, we show that it supports intrathymic T cell development, maturation, and exit into the periphery as mature CD4/CD8 double negative (DN) T cells with TCR-mediated functional capacity. Accordingly, we show how an αβTCR can recognise an intact foreign protein in an antibody-like manner.

Generation and repair of thymic epithelial cells

In the vertebrate immune system, thymus stromal microenvironments support the generation of αβT cells from immature thymocytes. Thymic epithelial cells are of particular importance, and the generation of cortical and medullary epithelial lineages from progenitor stages controls the initiation and maintenance of thymus function. Here, we discuss the developmental pathways that regulate thymic epithelial cell diversity during both the embryonic and postnatal periods. We also examine how thymus microenvironments respond to injury, with particular focus on mechanisms that ensure regeneration of thymic epithelial cells for the restoration of thymus function.

Hepatitis C virus chronicity and oncogenic potential: Vaccine development progress

Hepatitis C virus (HCV) infection is a major health problem worldwide. It can cause liver cirrhosis and hepatocellular carcinoma (HCC), making it a cause of morbidity from liver disease. Thus, there is an urgent need for a prophylactic HCV vaccine. Fortunately, modern medicine has transformed the therapy for HCV infection through development of direct-acting antiviral agents (DAAs), achieving high rates of sustained virologic response and giving significant relief from HCC and associated mortality, but unfortunately it fails to eradicate the risk of HCC, especially in HCV-cleared patients with already advanced liver disease. Additionally, DAA-cured patients do not develop sufficient antiviral immunity and are susceptible to reinfection. A comprehensive strategy to control HCV infection must include a vaccine development approach in which the host can develop humoral and cellular immunity to eradicate HCV successfully; however, this remains a challenge as HCV has developed systems to evade immune attacks from its host. This review highlights the current understanding of HCV's effect on liver disease and cancer progression, the nature of immune responses from cell populations interacting with HCV, and the current strategies for vaccine development. The information in this review will advance prophylactic intervention strategies for HCV infection, with the end goal being to prevent chronicity and subsequent liver disease leading to HCC.

Unravelling metabolic factors impacting iNKT cell biology in obesity

Obesity and related diseases have reached epidemic proportions and continue to rise. Beyond creating an economical burden, obesity and its co-morbidities are associated with shortened human life expectancy. Despite major advances, the underlying mechanisms of obesity remain not fully elucidated. Recently, several studies have highlighted that various immune cells are metabolically reprogrammed in obesity, thereby profoundly affecting the immune system. This sheds light on a new field of interest: the impact of obesity-related systemic metabolic changes affecting immune system that could lead to immunosurveillance loss. Among immune cells altered by obesity, invariant Natural Killer T (iNKT) cells have recently garnered intense focus due to their ability to recognize lipid antigen. While iNKT cells are well-described to be affected by obesity, how and to what extent immunometabolic factors (e.g., lipids, glucose, cytokines, adipokines, insulin and free fatty acids) can drive iNKT cells alterations remains unclear, but represent an emerging field of research. Here, we review the current knowledge on iNKT cells in obesity and discuss the immunometabolic factors that could modulate their phenotype and activity.

Innate immune response in acute critical illness: a narrative review

BACKGROUND

Activation of innate immunity is a first line of host defense during acute critical illness (ACI) that aims to contain injury and avoid tissue damages. Aberrant activation of innate immunity may also participate in the occurrence of organ failures during critical illness. This review aims to provide a narrative overview of recent advances in the field of innate immunity in critical illness, and to consider future potential therapeutic strategies.

MAIN TEXT

Understanding the underlying biological concepts supporting therapeutic strategies modulating immune response is essential in decision-making. We will develop the multiple facets of innate immune response, especially its cellular aspects, and its interaction with other defense mechanisms. We will first describe the pathophysiological mechanisms of initiation of innate immune response and its implication during ACI. We will then develop the amplification of innate immunity mediated by multiple effectors. Our review will mainly focus on myeloid and lymphoid cellular effectors, the major actors involved in innate immune-mediated organ failure. We will third discuss the interaction and integration of innate immune response in a global view of host defense, thus considering interaction with non-immune cells through immunothrombosis, immunometabolism and long-term reprogramming via trained immunity. The last part of this review will focus on the specificities of the immune response in children and the older population.

CONCLUSIONS

Recent understanding of the innate immune response integrates immunity in a highly dynamic global vision of host response. A better knowledge of the implicated mechanisms and their tissue-compartmentalization allows to characterize the individual immune profile, and one day eventually, to develop individualized bench-to-bedside immunomodulation approaches as an adjuvant resuscitation strategy.

T cell responses in immune-mediated IgA nephropathy

Immunoglobulin A nephropathy is a complex autoimmune disease with various underlying causes and significant clinical heterogeneity. There are large individual differences in its development, and the etiology and pathogenesis are still poorly understood. While it is known that immunobiological factors play a significant role in the pathophysiology of immunoglobulin A nephropathy, the specific nature of these factors has yet to be fully elucidated. Numerous investigations have verified that CD4+ and CD8+ T lymphocytes are involved in the immunopathogenesis of immunoglobulin A nephropathy. Furthermore, certain data also point to γδT cells' involvement in the pathophysiology of immunoglobulin A nephropathy. By thoroughly examining the mechanisms of action of these T cells in the context of immunoglobulin A nephropathy, this review sheds light on the immunopathogenesis of the disease and its associated factors. The review is intended to provide reference value for the future research in this field and promising treatment clues for clinical patients.

Thymic development of human natural killer T cells: recent advances and implications for immunotherapy

Invariant natural killer T (iNKT) cells are a subset of lipid-reactive, unconventional T cells that have anti-tumor properties that make them a promising target for cancer immunotherapy. Recent studies have deciphered the developmental pathway of human MAIT and Vγ9Vδ2 γδ-T cells as well as murine iNKT cells, yet our understanding of human NKT cell development is limited. Here, we provide an update in our understanding of how NKT cells develop in the human body and how knowledge regarding their development could enhance human treatments by targeting these cells.

γδ T cells as critical anti-tumor immune effectors

While the effector cells that mediate anti-tumor immunity have historically been attributed to αβ T cells and natural killer cells, γδ T cells are now being recognized as a complementary mechanism mediating tumor rejection. γδ T cells possess a host of functions ranging from antigen presentation to regulatory function and, importantly, have critical roles in eliciting anti-tumor responses where other immune effectors may be rendered ineffective. Recent discoveries have elucidated how these differing functions are mediated by γδ T cells with specific T cell receptors and spatial distribution. Their relative resistance to mechanisms of dysfunction like T cell exhaustion has spurred the development of therapeutic approaches exploiting γδ T cells, and an improved understanding of these cells should enable more effective immunotherapies.

NK-like CD8 T cell: one potential evolutionary continuum between adaptive memory and innate immunity

CD8 T cells are crucial adaptive immune cells with cytotoxicity to fight against pathogens or abnormal self-cells via major histocompatibility complex class I-dependent priming pathways. The composition of the memory CD8 T-cell pool is influenced by various factors. Physiological aging, chronic viral infection, and autoimmune diseases promote the accumulation of CD8 T cells with highly differentiated memory phenotypes. Accumulating studies have shown that some of these memory CD8 T cells also exhibit innate-like cytotoxicity and upregulate the expression of receptors associated with natural killer (NK) cells. Further analysis shows that these NK-like CD8 T cells have transcriptional profiles of both NK and CD8 T cells, suggesting the transformation of CD8 T cells into NK cells. However, the specific induction mechanism underlying NK-like transformation and the implications of this process for CD8 T cells are still unclear. This review aimed to deduce the possible differentiation model of NK-like CD8 T cells, summarize the functions of major NK-cell receptors expressed on these cells, and provide a new perspective for exploring the role of these CD8 T cells in health and disease.

Phosphatidic Acid Promoting the Generation of Interleukin-17A Producing Double-Negative T Cells by Enhancing mTORC1 Signaling in Lupus

OBJECTIVE

The goal was to investigate the role and intracellular regulatory mechanisms of double-negative T (DNT) cells in the pathogenesis of systemic lupus erythematosus (SLE).

METHODS

DNT cells were assessed in murine models, patients with SLE, and controls using flow cytometry (FCM). DNT cells from either resiquimod (R848) or vehicle-treated C57BL/6 (B6) mice were cultured with B cells from R848-treated mice to explore functions. Differential mechanistic target of rapamycin (mTOR) pathway signaling in DNT cells measured using FCM and quantitative polymerase chain reaction was validated by rapamycin inhibition. Candidate lipid metabolites detected using liquid chromatography with electrospray ionization mass spectrometry/mass spectrometry were functionally assessed in DNT cell cultures.

RESULTS

DNT cells were markedly increased in both spontaneous and induced mouse lupus models and in patients with SLE. Expanded DNT cells from R848-treated B6 mice produced elevated interleukin (IL)-17A and IgG with increased germinal center B (GCB) cells. Expansion of DNT cells associated with activation of mTORC1 pathway that both IL-17A levels and the number of DNT cells exhibited dose-dependent reduction with rapamycin treatment. Lipidomics studies revealed differential patterns of lipid metabolites in T cells of R848-treated mice. Among candidate metabolites, elevated phosphatidic acid (PA) that was partially controlled by phospholipase D2 increased the expression of the mTORC1 downstream target p-S6 and positively expanded IL-17A-producing DNT cells. Similarly, elevated proportions of circulating DNT cells in patients with SLE correlated with disease activity and proteinuria, and IL-17A secretion was elevated after in vitro PA stimulation.

CONCLUSION

The accumulation of PA in T cells could activate the mTORC1 pathway, promoting DNT cell expansion and IL-17A secretion, resulting in GCB cell abnormalities in lupus.

Innate-like T cells in liver disease

Mammalian innate-like T cells (ILTCs), including mucosal-associated invariant T (MAIT), natural killer T (NKT), and γδ T cells, are abundant tissue-resident lymphocytes that have recently emerged as orchestrators of hepatic inflammation, tissue repair, and immune homeostasis. This review explores the involvement of different ILTC subsets in liver diseases. We explore the mechanisms underlying the pro- and anti-inflammatory effector functions of ILTCs in a context-dependent manner. We highlight latest findings regarding the dynamic interplay between ILTC functional subsets and other immune and parenchymal cells which may inform candidate immunomodulatory strategies to achieve improved clinical outcomes in liver diseases. We present new insights into how distinct gene expression programs in hepatic ILTCs are induced, maintained, and reprogrammed in a context- and disease stage-dependent manner.

Advances in understanding immune homeostasis in latent tuberculosis infection

Nearly one-fourth of the global population is infected by Mycobacterium tuberculosis (Mtb), and approximately 90%-95% remain asymptomatic as latent tuberculosis infection (LTBI), an estimated 5%-10% of those with latent infections will eventually progress to active tuberculosis (ATB). Although it is widely accepted that LTBI transitioning to ATB results from a disruption of host immune balance and a weakening of protective immune responses, the exact underlying immunological mechanisms that promote this conversion are not well characterized. Thus, it is difficult to accurately predict tuberculosis (TB) progression in advance, leaving the LTBI population as a significant threat to TB prevention and control. This article systematically explores three aspects related to the immunoregulatory mechanisms and translational research about LTBI: (1) the distinct immunocytological characteristics of LTBI and ATB, (2) LTBI diagnostic markers discovery related to host anti-TB immunity and metabolic pathways, and (3) vaccine development focus on LTBI. This article is categorized under: Infectious Diseases > Molecular and Cellular Physiology Infectious Diseases > Genetics/Genomics/Epigenetics Immune System Diseases > Genetics/Genomics/Epigenetics.

A natural killer T cell nanoagonist-initiated immune cascade for hepatocellular carcinoma synergistic immunotherapy

Natural killer T (NKT) cell-mediated immunotherapy shows great promise in hepatocellular carcinoma featuring an inherent immunosuppressive microenvironment. However, targeted delivery of NKT cell agonists remains challenging. Here, we developed a hyaluronic acid (HA) modified metal organic framework (zeolitic imidazolate framework-8, ZIF-8) to encapsulate α-galactosylceramide (α-Galcer), a classic NKT cell agonist, and doxorubicin (DOX) for eliminating liver cancer, denoted as α-Galcer/DOX@ZIF-8@HA. In the tumor microenvironment (TME), these pH-responsive nano-frameworks can gradually collapse to release α-Galcer for activating NKT cells and further boosting other immune cells in order to initiate an antitumor immune cascade. Along with DOX, the released α-Galcer enabled efficient NKT cell activation in TME for synergistic immunotherapy and tumor elimination, leading to evident tumor suppression and prolonged animal survival in both subcutaneous and orthotopic liver tumor models. Manipulating NKT cell agonists into functional nano-frameworks in TME may be matched with other advanced managements applied in a wider range of cancer therapies.

An update on periodontal inflammation and bone loss

Periodontal disease is a chronic inflammatory condition that affects the supporting structures of the teeth, including the periodontal ligament and alveolar bone. Periodontal disease is due to an immune response that stimulates gingivitis and periodontitis, and its systemic consequences. This immune response is triggered by bacteria and may be modulated by environmental conditions such as smoking or systemic disease. Recent advances in single cell RNA-seq (scRNA-seq) and in vivo animal studies have provided new insight into the immune response triggered by bacteria that causes periodontitis and gingivitis. Dysbiosis, which constitutes a change in the bacterial composition of the microbiome, is a key factor in the initiation and progression of periodontitis. The host immune response to dysbiosis involves the activation of various cell types, including keratinocytes, stromal cells, neutrophils, monocytes/macrophages, dendritic cells and several lymphocyte subsets, which release pro-inflammatory cytokines and chemokines. Periodontal disease has been implicated in contributing to the pathogenesis of several systemic conditions, including diabetes, rheumatoid arthritis, cardiovascular disease and Alzheimer's disease. Understanding the complex interplay between the oral microbiome and the host immune response is critical for the development of new therapeutic strategies for the prevention and treatment of periodontitis and its systemic consequences.

Evaluating the link between immune characteristics and attention deficit hyperactivity disorder through a bi-directional Mendelian randomization study

Context

Despite the recognition of attention deficit hyperactivity disorder (ADHD) as a multifaceted neurodevelopmental disorder, its core causes are still ambiguous. The objective of this study was to explore if the traits of circulating immune cells contribute causally to susceptibility to ADHD.

Methods

By employing a unified GWAS summary data covering 731 immune traits from the GWAS Catalog (accession numbers from GCST0001391 to GCST0002121), our analysis focused on the flow cytometry of lymphocyte clusters, encompassing 3,757 Sardinians, to identify genetically expected immune cells. Furthermore, we obtained summarized GWAS statistics from the Psychiatric Genomics Consortium to evaluate the genetic forecasting of ADHD. The studies employed ADHD2019 (20,183 cases and 35,191 controls from the 2019 GWAS ADHD dataset) and ADHD2022 (38,691 cases and 275,986 controls from the 2022 GWAS ADHD dataset). Through the examination of genome-wide association signals, we identified shared genetic variances between circulating immune cells and ADHD, employing the comprehensive ADHD2022 dataset. We primarily utilized inverse variance weighted (IVW) and weighted median methods in our Mendelian randomization research and sensitivity assessments to evaluate diversity and pleiotropy.

Results

After adjusting for false discovery rate (FDR), three distinct immunophenotypes were identified as associated with the risk of ADHD: CD33 in Im MDSC (OR=1.03, CI: 1.01~1.04, P=3.04×10-5, PFDR =0.015), CD8br NKT %T cell (OR=1.08, 95%CI: 1.04~1.12, P=9.33×10-5, PFDR =0.023), and CD8br NKT %lymphocyte (OR=1.08, 95%CI: 1.03~1.12, P=3.59×10-4, PFDR =0.066). Furthermore, ADHD showed no statistical effects on immunophenotypes. It's worth noting that 20 phenotypes exist where ADHD's appearance could diminish 85% of immune cells, including FSC-A in myeloid DC (β= -0.278, 95% CI: 0.616~0.931, P=0.008), CD3 in CD45RA- CD4+ (β= -0.233, 95% CI: 0.654~0.960, P=0.017), CD62L- monocyte AC (β=0.227, 95% CI: 0.038~1.518, P=0.019), CD33 in CD33br HLA DR+ CD14dim (β= -0.331, 95% CI: 0.543~0.950, P=0.020), and CD25 in CD39+ resting Treg (β=0.226, 95% CI: 1.522, P=0.022), and FSC-A in monocytes (β= -0.255, 95% CI: 0.621~0.967, P=0.234), among others.

Conclusion

Studies indicate that the immune system's response influences the emergence of ADHD. The findings greatly improve our understanding of the interplay between immune responses and ADHD risk, aiding in the development of treatment strategies from an immunological perspective.

Metabolic heterogeneity in tumor microenvironment - A novel landmark for immunotherapy

The surrounding non-cancer cells and tumor cells that make up the tumor microenvironment (TME) have various metabolic rhythms. TME metabolic heterogeneity is influenced by the intricate network of metabolic control within and between cells. DNA, protein, transport, and microbial levels are important regulators of TME metabolic homeostasis. The effectiveness of immunotherapy is also closely correlated with alterations in TME metabolism. The response of a tumor patient to immunotherapy is influenced by a variety of variables, including intracellular metabolic reprogramming, metabolic interaction between cells, ecological changes within and between tumors, and general dietary preferences. Although immunotherapy and targeted therapy have made great strides, their use in the accurate identification and treatment of tumors still has several limitations. The function of TME metabolic heterogeneity in tumor immunotherapy is summarized in this article. It focuses on how metabolic heterogeneity develops and is regulated as a tumor progresses, the precise molecular mechanisms and potential clinical significance of imbalances in intracellular metabolic homeostasis and intercellular metabolic coupling and interaction, as well as the benefits and drawbacks of targeted metabolism used in conjunction with immunotherapy. This offers insightful knowledge and important implications for individualized tumor patient diagnosis and treatment plans in the future.

Comprehensive study of the interplay between immunological and metabolic factors in hepatic steatosis

The pathophysiology of hepatic steatosis is thoroughly reviewed in this comprehensive report, with particular attention to the complex interactions between inflammatory pathways, insulin resistance, lipid metabolism, metabolic dysregulation, and immunological responses in the liver including non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), and hepatocellular carcinoma (HCC). The study highlights the role of immune cell regulation in disease progression and explores the potential of immune cell-specific treatments for treating hepatic disorders. The development of liver disorders is significantly influenced by immune cells, including dendritic cells, T cells, and natural killer cells. Clinical investigations show that immune cell-specific treatments can effectively reduce liver fibrosis and inflammation. Future research should focus on finding new immunological targets for therapeutic interventions, as well as addressing the management challenges associated with NAFLD/NASH. Hepatic immune microorganisms also impact liver homeostasis and disorders. Improvements in immune cell regulation and liver transplantation methods give patients hope for better prognoses. Important phases include optimizing the selection of donors for malignancy of the liver, using machine perfusion for organ preservation, and fine-tuning immunosuppressive strategies. For focused treatments in hepatic steatosis, it is imperative to understand the intricate interactions between immune and metabolic variables. Understanding the liver's heterogeneous immune profile, encompassing a range of immune cell subpopulations, is crucial for formulating focused therapeutic interventions. To improve patient care and outcomes in hepatic illnesses, there is an urgent need for further research and innovation. Therefore, to effectively treat hepatic steatosis, it is important to enhance therapeutic techniques and maximize liver transplantation strategies.

Invariant γδTCR natural killer-like effector T cells in the naked mole-rat

The naked mole-rat (Heterocephalus glaber) is a long-lived rodent species showing resistance to the development of cancer. Although naked mole-rats have been reported to lack natural killer (NK) cells, γδ T cell-based immunity has been suggested in this species, which could represent an important arm of the immune system for antitumor responses. Here, we investigate the biology of these unconventional T cells in peripheral tissues (blood, spleen) and thymus of the naked mole-rat at different ages by TCR repertoire profiling and single-cell gene expression analysis. Using our own TCR annotation in the naked mole-rat genome, we report that the γδ TCR repertoire is dominated by a public invariant Vγ4-2/Vδ1-4 TCR, containing the complementary-determining-region-3 (CDR3)γ CTYWDSNYAKKLF / CDR3δ CALWELRTGGITAQLVF that are likely generated by short-homology-repeat-driven DNA rearrangements. This invariant TCR is specifically found in γδ T cells expressing genes associated with NK cytotoxicity and is generated in both the thoracic and cervical thymus of the naked mole-rat until adult life. Our results indicate that invariant Vγ4-2/Vδ1-4 NK-like effector T cells in the naked mole-rat can contribute to tumor immunosurveillance by γδ TCR-mediated recognition of a common molecular signal.

Free sugar intake is associated with reduced proportion of circulating invariant natural killer T cells among women experiencing overweight and obesity

Background

Higher prevalence of obesity has been observed among women compared to men, which can be explained partly by the higher consumption of sweets and physical inactivity. Obesity can alter immune cell infiltration, and therefore increase the susceptibility to develop chronic inflammation and metabolic disorders. In this study, we aimed to explore the association between free sugar intake and other unhealthy lifestyle habits in relation to the proportion of circulating iNKT cells among women with healthy weight and women experiencing overweight and obesity.

Methods

A cross-sectional study was conducted on 51 Saudi women > 18 years, wherein their daily free sugar intake was assessed using the validated Food Frequency Questionnaire. Data on smoking status, physical activity, and supplement use were also collected. Anthropometric data including height, weight, waist circumference were objectively measured from each participants. The proportion of circulating iNKT cells was determined using flow cytometry.

Results

Smoking, physical activity, supplement use, and weight status were not associated with proportion of circulating iNKT cells. Significant association was found between proportion of circulating iNKT cells and total free sugar intake and free sugar intake coming from solid food sources only among women experiencing overweight and obesity (Beta: -0.10: Standard Error: 0.04 [95% Confidence Interval: -0.18 to -0.01], p= 0.034) and (Beta: -0.15: Standard Error: 0.05 [95% Confidence Interval: -0.25 to -0.05], p= 0.005), respectively.

Conclusion

Excessive free sugar consumption may alter iNKT cells and consequently increase the risk for chronic inflammation and metabolic disorders.

Immune cell trafficking: a novel perspective on the gut-skin axis

Immune cell trafficking, an essential mechanism for maintaining immunological homeostasis and mounting effective responses to infections, operates under a stringent regulatory framework. Recent advances have shed light on the perturbation of cell migration patterns, highlighting how such disturbances can propagate inflammatory diseases from their origin to distal organs. This review collates and discusses current evidence that demonstrates atypical communication between the gut and skin, which are conventionally viewed as distinct immunological spheres, in the milieu of inflammation. We focus on the aberrant, reciprocal translocation of immune cells along the gut-skin axis as a pivotal factor linking intestinal and dermatological inflammatory conditions. Recognizing that the translation of these findings into clinical practices is nascent, we suggest that therapeutic strategies aimed at modulating the axis may offer substantial benefits in mitigating the widespread impact of inflammatory diseases.

Immunotherapeutic implications of negative regulation by protein tyrosine phosphatases in T cells: the emerging cases of PTP1B and TCPTP

In the context of inflammation, T cell activation occurs by the concerted signals of the T cell receptor (TCR), co-stimulatory receptors ligation, and a pro-inflammatory cytokine microenvironment. Fine-tuning these signals is crucial to maintain T cell homeostasis and prevent self-reactivity while offering protection against infectious diseases and cancer. Recent developments in understanding the complex crosstalk between the molecular events controlling T cell activation and the balancing regulatory cues offer novel approaches for the development of T cell-based immunotherapies. Among the complex regulatory processes, the balance between protein tyrosine kinases (PTK) and the protein tyrosine phosphatases (PTPs) controls the transcriptional and metabolic programs that determine T cell function, fate decision, and activation. In those, PTPs are de facto regulators of signaling in T cells acting for the most part as negative regulators of the canonical TCR pathway, costimulatory molecules such as CD28, and cytokine signaling. In this review, we examine the function of two close PTP homologs, PTP1B (PTPN1) and T-cell PTP (TCPTP; PTPN2), which have been recently identified as promising candidates for novel T-cell immunotherapeutic approaches. Herein, we focus on recent studies that examine the known contributions of these PTPs to T-cell development, homeostasis, and T-cell-mediated immunity. Additionally, we describe the signaling networks that underscored the ability of TCPTP and PTP1B, either individually and notably in combination, to attenuate TCR and JAK/STAT signals affecting T cell responses. Thus, we anticipate that uncovering the role of these two PTPs in T-cell biology may lead to new treatment strategies in the field of cancer immunotherapy. This review concludes by exploring the impacts and risks that pharmacological inhibition of these PTP enzymes offers as a therapeutic approach in T-cell-based immunotherapies.

Evolution of T cells in the cancer-resistant naked mole-rat

Naked mole-rats (NMRs) are best known for their extreme longevity and cancer resistance, suggesting that their immune system might have evolved to facilitate these phenotypes. Natural killer (NK) and T cells have evolved to detect and destroy cells infected with pathogens and to provide an early response to malignancies. While it is known that NMRs lack NK cells, likely lost during evolution, little is known about their T-cell subsets in terms of the evolution of the genes that regulate their function, their clonotypic diversity, and the thymus where they mature. Here we find, using single-cell transcriptomics, that NMRs have a large circulating population of γδT cells, which in mice and humans mostly reside in peripheral tissues and induce anti-cancer cytotoxicity. Using single-cell-T-cell-receptor sequencing, we find that a cytotoxic γδT-cell subset of NMRs harbors a dominant clonotype, and that their conventional CD8 αβT cells exhibit modest clonotypic diversity. Consistently, perinatal NMR thymuses are considerably smaller than those of mice yet follow similar involution progression. Our findings suggest that NMRs have evolved under a relaxed intracellular pathogenic selective pressure that may have allowed cancer resistance and longevity to become stronger targets of selection to which the immune system has responded by utilizing γδT cells.

CTLs heterogeneity and plasticity: implications for cancer immunotherapy

Cytotoxic T lymphocytes (CTLs) play critical antitumor roles, encompassing diverse subsets including CD4+, NK, and γδ T cells beyond conventional CD8+ CTLs. However, definitive CTLs biomarkers remain elusive, as cytotoxicity-molecule expression does not necessarily confer cytotoxic capacity. CTLs differentiation involves transcriptional regulation by factors such as T-bet and Blimp-1, although epigenetic regulation of CTLs is less clear. CTLs promote tumor killing through cytotoxic granules and death receptor pathways, but may also stimulate tumorigenesis in some contexts. Given that CTLs cytotoxicity varies across tumors, enhancing this function is critical. This review summarizes current knowledge on CTLs subsets, biomarkers, differentiation mechanisms, cancer-related functions, and strategies for improving cytotoxicity. Key outstanding questions include refining the CTLs definition, characterizing subtype diversity, elucidating differentiation and senescence pathways, delineating CTL-microbe relationships, and enabling multi-omics profiling. A more comprehensive understanding of CTLs biology will facilitate optimization of their immunotherapy applications. Overall, this review synthesizes the heterogeneity, regulation, functional roles, and enhancement strategies of CTLs in antitumor immunity, highlighting gaps in our knowledge of subtype diversity, definitive biomarkers, epigenetic control, microbial interactions, and multi-omics characterization. Addressing these questions will refine our understanding of CTLs immunology to better leverage cytotoxic functions against cancer.

Mechanism study of ubiquitination in T cell development and autoimmune disease

T cells play critical role in multiple immune processes including antigen response, tumor immunity, inflammation, self-tolerance maintenance and autoimmune diseases et. Fetal liver or bone marrow-derived thymus-seeding progenitors (TSPs) settle in thymus and undergo T cell-lineage commitment, proliferation, T cell receptor (TCR) rearrangement, and thymic selections driven by microenvironment composed of thymic epithelial cells (TEC), dendritic cells (DC), macrophage and B cells, thus generating T cells with diverse TCR repertoire immunocompetent but not self-reactive. Additionally, some self-reactive thymocytes give rise to Treg with the help of TEC and DC, serving for immune tolerance. The sequential proliferation, cell fate decision, and selection during T cell development and self-tolerance establishment are tightly regulated to ensure the proper immune response without autoimmune reaction. There are remarkable progresses in understanding of the regulatory mechanisms regarding ubiquitination in T cell development and the establishment of self-tolerance in the past few years, which holds great potential for further therapeutic interventions in immune-related diseases.

Pyroptosis-Derived Long Noncoding RNA Profiles Reveal a Novel Signature for Evaluating the Prognosis of Patients With Lung Adenocarcinoma

PURPOSE

Long noncoding RNAs (lncRNAs) were recently implicated in modifying pyroptosis. Nonetheless, pyroptosis-related lncRNAs and their possible clinical relevance persist largely uninvestigated in lung adenocarcinoma (LUAD).

MATERIALS AND METHODS

A sum of 921 samples were collected from three independent data sets. We obtained pyroptosis-related genes from both the Molecular Signatures Database and relevant literature sources and used four machine learning techniques, comprising stepwise Cox, ridge regression, least absolute shrinkage and selection operator, and random forest. Multiple bioinformatics approaches were used to further investigate the underlying mechanisms.

RESULTS

In total, 39 differentially expressed pyroptosis genes were identified by comparing normal and tumor samples. Correlation analysis revealed 933 pyroptosis-related lncRNAs. Furthermore, univariate Cox regression determined 11 lncRNAs that exhibited stable associations with prognosis in the three cohorts, which were used to construct the pyroptosis-derived lncRNA signature. After analyzing the optimal results from four machine learning algorithms, we ultimately selected random forest to develop the pyroptosis-derived lncRNA signature. This signature was proven to be an independent prognostic factor and exhibited robust performance in three cohorts.

CONCLUSION

We provided novel insight and established a pyroptosis-derived lncRNA signature for patients with LUAD, exhibiting strong predictive capabilities in both the training and validation sets.

Role of innate T cells in necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a destructive gastrointestinal disease primarily affecting preterm babies. Despite advancements in neonatal care, NEC remains a significant cause of morbidity and mortality in neonatal intensive care units worldwide and the etiology of NEC is still unclear. Risk factors for NEC include prematurity, very low birth weight, feeding with formula, intestinal dysbiosis and bacterial infection. A review of the literature would suggest that supplementation of prebiotics and probiotics prevents NEC by altering the immune responses. Innate T cells, a highly conserved subpopulation of T cells that responds quickly to stimulation, develops differently from conventional T cells in neonates. This review aims to provide a succinct overview of innate T cells in neonates, encompassing their phenotypic characteristics, functional roles, likely involvement in the pathogenesis of NEC, and potential therapeutic implications.

STING Agonist-Loaded Nanoparticles Promotes Positive Regulation of Type I Interferon-Dependent Radioimmunotherapy in Rectal Cancer

Hypoxia-associated radioresistance in rectal cancer (RC) has severely hampered the response to radioimmunotherapy (iRT), necessitating innovative strategies to enhance RC radiosensitivity and improve iRT efficacy. Here, a catalytic radiosensitizer, DMPtNPS, and a STING agonist, cGAMP, are integrated to overcome RC radioresistance and enhance iRT. DMPtNPS promotes efficient X-ray energy transfer to generate reactive oxygen species, while alleviating hypoxia within tumors, thereby increasing radiosensitivity. Mechanistically, the transcriptomic and immunoassay analysis reveal that the combination of DMPtNPS and RT provokes bidirectional regulatory effects on the immune response, which may potentially reduce the antitumor efficacy. To mitigate this, cGAMP is loaded into DMPtNPS to reverse the negative impact of DMPtNPS and RT on the tumor immune microenvironment (TiME) through the type I interferon-dependent pathway, which promotes cancer immunotherapy. In a bilateral tumor model, the combination treatment of RT, DMPtNPS@cGAMP, and αPD-1 demonstrates a durable complete response at the primary site and enhanced abscopal effect at the distant site. This study highlights the critical role of incorporating catalytic radiosensitizers and STING agonists into the iRT approach for RC.

IL-35: New Target for Immunotherapy Targeting the Tumor Microenvironment

Interleukin 35(IL-35) is a newly discovered inhibitory cytokine of the IL12 family. More recently, IL-35 was found to be increased in the tumor microenvironment (TME) and peripheral blood of many patients with cancer, indicating that it plays an important role in the TME. Tumors secrete cytokines that recruit myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Treg) into the TME to promote malignant progression, which is a great challenge for cancer treatment. Radiotherapy causes serious adverse effects, and tumor resistance to immune checkpoint inhibitors is still an unsolved challenge. Thus, new cancer therapy approaches are urgently needed. Numerous studies have shown that IL-35 can recruit immunosuppressive cells to enable tumor immune escape by promoting the conversion of immune cells into a tumor growth-promoting phenotype as well as facilitating tumor angiogenesis. IL-35-neutralizing antibodies were found to boost the chemotherapeutic effect of gemcitabine and considerably reduce the microvascular density of pancreatic cancer in mice. Therefore, targeting IL-35 in the TME provides a promising cancer treatment target. In addition, IL-35 may be used as an independent prognostic factor for some tumors in the near future. This review intends to reveal the interplay of IL-35 with immune cells in the TME, which may provide new options for the treatment of cancer.

Liver fibrosis in NAFLD/NASH: from pathophysiology towards diagnostic and therapeutic strategies

Liver fibrosis, as an excess deposition of extracellular matrix (ECM) components, results from chronic liver injury as well as persistent activation of inflammatory response and of fibrogenesis. Liver fibrosis is a major determinant for chronic liver disease (CLD) progression and in the last two decades our understanding on the major molecular and cellular mechanisms underlying the fibrogenic progression of CLD has dramatically improved, boosting pre-clinical studies and clinical trials designed to find novel therapeutic approaches. From these studies several critical concepts have emerged, starting to reveal the complexity of the pro-fibrotic microenvironment which involves very complex, dynamic and interrelated interactions between different hepatic and extrahepatic cell populations. This review will offer first a recapitulation of established and novel pathophysiological basic principles and concepts by intentionally focus the attention on NAFLD/NASH, a metabolic-related form of CLD with a high impact on the general population and emerging as a leading cause of CLD worldwide. NAFLD/NASH-related pro-inflammatory and profibrogenic mechanisms will be analysed as well as novel information on cells, mediators and signalling pathways which have taken advantage from novel methodological approaches and techniques (single cell genomics, imaging mass cytometry, novel in vitro two- and three-dimensional models, etc.). We will next offer an overview on recent advancement in diagnostic and prognostic tools, including serum biomarkers and polygenic scores, to support the analysis of liver biopsies. Finally, this review will provide an analysis of current and emerging therapies for the treatment of NAFLD/NASH patients.

Fc-fused IL-7 provides broad antiviral effects against respiratory virus infections through IL-17A-producing pulmonary innate-like T cells

Repeated pandemics caused by the influenza virus and severe acute respiratory syndrome coronavirus (SARS-CoV) have resulted in serious problems in global public health, emphasizing the need for broad-spectrum antiviral therapeutics against respiratory virus infections. Here, we show the protective effects of long-acting recombinant human interleukin-7 fused with hybrid Fc (rhIL-7-hyFc) against major respiratory viruses, including influenza virus, SARS-CoV-2, and respiratory syncytial virus. Administration of rhIL-7-hyFc in a therapeutic or prophylactic regimen induces substantial antiviral effects. During an influenza A virus (IAV) infection, rhIL-7-hyFc treatment increases pulmonary T cells composed of blood-derived interferon γ (IFNγ)+ conventional T cells and locally expanded IL-17A+ innate-like T cells. Single-cell RNA transcriptomics reveals that rhIL-7-hyFc upregulates antiviral genes in pulmonary T cells and induces clonal expansion of type 17 innate-like T cells. rhIL-7-hyFc-mediated disease prevention is dependent on IL-17A in both IAV- and SARS-CoV-2-infected mice. Collectively, we suggest that rhIL-7-hyFc can be used as a broadly active therapeutic for future respiratory virus pandemic.

Overcoming cancer risk in inflammatory bowel disease: new insights into preventive strategies and pathogenesis mechanisms including interactions of immune cells, cancer signaling pathways, and gut microbiota

Inflammatory bowel disease (IBD), characterized primarily by gastrointestinal inflammation, predominantly manifests as Crohn's disease (CD) and ulcerative colitis (UC). It is acknowledged that Inflammation plays a significant role in cancer development and patients with IBD have an increased risk of various cancers. The progression from inflammation to carcinogenesis in IBD is a result of the interplay between immune cells, gut microbiota, and carcinogenic signaling pathways in epithelial cells. Long-term chronic inflammation can lead to the accumulation of mutations in epithelial cells and the abnormal activation of carcinogenic signaling pathways. Furthermore, Immune cells play a pivotal role in both the acute and chronic phases of IBD, contributing to the transformation from inflammation to tumorigenesis. And patients with IBD frequently exhibit dysbiosis of the intestinal microbiome. Disruption of the gut microbiota and subsequent immune dysregulation are central to the pathogenesis of both IBD and colitis associated colorectal cancer (CAC). The proactive management of inflammation combined with regular endoscopic and tumor screenings represents the most direct and effective strategy to prevent the IBD-associated cancer.

Natural killer cells and innate lymphoid cells but not NKT cells are mature in their cytokine production at birth

Early life is a time of increased susceptibility to infectious diseases and development of allergy. Innate lymphocytes are crucial components of the initiation and regulation of immune responses at mucosal surfaces, but functional differences in innate lymphocytes early in life are not fully described. We aimed to characterize the abundance and function of different innate lymphocyte cell populations in cord blood in comparison to that of adults. Blood was collected from adult donors and umbilical vessels at birth. Multicolor flow cytometry panels were used to identify and characterize lymphocyte populations and their capacity to produce hallmark cytokines. Lymphocytes were more abundant in cord blood compared to adults, however, mucosal-associated invariant T cells and natural killer T (NKT)-like cells, were far less abundant. The capacity of NKT-like cells to produce cytokines and their expression of the cytotoxic granule protein granzyme B and the marker of terminal differentiation CD57 were much lower in cord blood than in adults. In contrast, natural killer (NK) cells were as abundant in cord blood as in adults, they could produce IFNγ, and their expression of granzyme B was not significantly different from that of adult NK cells, although CD57 expression was lower. All innate lymphoid cell (ILC) subsets were more abundant in cord blood, and ILC1 and ILC2 were capable of production of IFNγ and IL-13, respectively. In conclusion, different innate lymphoid cells differ in both abundance and function in peripheral blood at birth and with important implications for immunity in early life.

Dysfunctional states of unconventional T-cell subsets in cancer

Unconventional T cells represent a promising therapeutic agent to overcome the current limitations of immunotherapies due to their universal T-cell receptors, ability to respond directly to cytokine stimulation, and capacity to recruit and modulate conventional immune cells in the tumor microenvironment. Like conventional T cells, unconventional T cells can enter a dysfunctional state, and the functional differences associated with this state may provide insight into the discrepancies observed in their role in antitumor immunity in various cancers. The exhaustive signature of unconventional T cells differs from conventional αβ T cells, and understanding the differences in the mechanisms underlying exhaustive differentiation in these cell types may aid in the discovery of new treatments to improve sustained antitumor responses. Ongoing clinical trials investigating therapies that leverage unconventional T-cell populations have shown success in treating hematologic malignancies and reducing the immunosuppressive tumor environment. However, several hurdles remain to extend these promising results into solid tumors. Here we discuss the current knowledge on unconventional T-cell function/dysfunction and consider how the incorporation of therapies that modulate unconventional T-cell exhaustion may aid in overcoming the current limitations of immunotherapy. Additionally, we discuss how components of the tumor microenvironment alter the functions of unconventional T cells and how these changes can affect tumor infiltration by lymphocytes and alter conventional T-cell responses.

Potential of MAIT cells to modulate asthma

Despite recent advances in asthma treatments, the search for novel therapies remains necessary because there are still patients with recurrent asthma exacerbations and poor responses to the existing treatments. Since group 2 innate lymphoid cells (ILC2) play a pivotal role in asthma by triggering and exacerbating type 2 inflammation, controlling ILC2s function is key to combating severe asthma. Mucosal-associated invariant T (MAIT) cells are innate-like T cells abundant in humans and are activated both in a T cell receptor-dependent and -independent manner. MAIT cells are composed of MAIT1 and MAIT17 based on the expression of transcription factors T-bet and RORγt, respectively. MAIT cells play pivotal roles in host defense against pathogens and in tissue repair and are essential for the maintenance of immunity and hemostasis. Our recent studies revealed that MAIT cells inhibit both ILC2 proliferation and functions in a mouse model of airway inflammation. MAIT cells may alleviate airway inflammation in two ways, by promoting airway epithelial cell barrier repair and by repressing ILC2s. Therefore, reagents that promote MAIT cell-mediated suppression of ILC2 proliferation and function, or designer MAIT cells (genetically engineered to suppress ILC2s or promote repair of airway damage), may be effective therapeutic agents for severe asthma.

Current annotation strategies for T cell phenotyping of single-cell RNA-seq data

Single-cell RNA sequencing (scRNA-seq) has become a popular technique for interrogating the diversity and dynamic nature of cellular gene expression and has numerous advantages in immunology. For example, scRNA-seq, in contrast to bulk RNA sequencing, can discern cellular subtypes within a population, which is important for heterogenous populations such as T cells. Moreover, recent advancements in the technology allow the parallel capturing of the highly diverse T-cell receptor (TCR) sequence with the gene expression. However, the field of single-cell RNA sequencing data analysis is still hampered by a lack of gold-standard cell phenotype annotation. This problem is particularly evident in the case of T cells due to the heterogeneity in both their gene expression and their TCR. While current cell phenotype annotation tools can differentiate major cell populations from each other, labelling T-cell subtypes remains problematic. In this review, we identify the common automated strategy for annotating T cells and their subpopulations, and also describe what crucial information is still missing from these tools.

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.

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.

Regulation of ferroptosis-related genes in CD8+ NKT cells and classical monocytes may affect the immunotherapy response after combined treatment in triple negative breast cancer

BACKGROUND

Drug resistance has led to the failure of immunotherapy in triple negative breast cancer patients. Here we aimed to explore the mechanisms of drug resistance in patients in order to enhance their response to immunotherapy.

METHODS

We downloaded publicly available single-cell RNA-sequencing data of peripheral blood mononuclear cells from patients after treatment to investigate the possible mechanisms of drug resistance. The publicly available TCGA transcriptomic data and somatic mutation data were used for further validation. In this study, a series of bioinformatics and machine learning methods were employed.

RESULTS

We identified the vital roles of CD8+ NKT cells and classical monocytes in the immunotherapy response of triple-negative breast cancer patients. The proportion of these cell types was significantly increased in group partial response. We also found that downregulation of ferroptosis-related genes regulates the immune pathway. The analysis of scRNA data and TCGA transcriptomic data presented that DUSP1 may play a crucial role in immunotherapy resistance.

CONCLUSION

Overall, the composition of the tumor microenvironment affects the immunotherapy response of patients, and DUSP1 may be a potential target for overcoming drug resistance.

γδ T cells: origin and fate, subsets, diseases and immunotherapy

The intricacy of diseases, shaped by intrinsic processes like immune system exhaustion and hyperactivation, highlights the potential of immune renormalization as a promising strategy in disease treatment. In recent years, our primary focus has centered on γδ T cell-based immunotherapy, particularly pioneering the use of allogeneic Vδ2+ γδ T cells for treating late-stage solid tumors and tuberculosis patients. However, we recognize untapped potential and optimization opportunities to fully harness γδ T cell effector functions in immunotherapy. This review aims to thoroughly examine γδ T cell immunology and its role in diseases. Initially, we elucidate functional differences between γδ T cells and their αβ T cell counterparts. We also provide an overview of major milestones in γδ T cell research since their discovery in 1984. Furthermore, we delve into the intricate biological processes governing their origin, development, fate decisions, and T cell receptor (TCR) rearrangement within the thymus. By examining the mechanisms underlying the anti-tumor functions of distinct γδ T cell subtypes based on γδTCR structure or cytokine release, we emphasize the importance of accurate subtyping in understanding γδ T cell function. We also explore the microenvironment-dependent functions of γδ T cell subsets, particularly in infectious diseases, autoimmune conditions, hematological malignancies, and solid tumors. Finally, we propose future strategies for utilizing allogeneic γδ T cells in tumor immunotherapy. Through this comprehensive review, we aim to provide readers with a holistic understanding of the molecular fundamentals and translational research frontiers of γδ T cells, ultimately contributing to further advancements in harnessing the therapeutic potential of γδ T cells.

Transcriptomes and metabolism define mouse and human MAIT cell populations

Mucosal-associated invariant T (MAIT) cells are a subset of T lymphocytes that respond to microbial metabolites. We defined MAIT cell populations in different organs and characterized the developmental pathway of mouse and human MAIT cells in the thymus using single-cell RNA sequencing and phenotypic and metabolic analyses. We showed that the predominant mouse subset, which produced IL-17 (MAIT17), and the subset that produced IFN-γ (MAIT1) had not only greatly different transcriptomes but also different metabolic states. MAIT17 cells in different organs exhibited increased lipid uptake, lipid storage, and mitochondrial potential compared with MAIT1 cells. All these properties were similar in the thymus and likely acquired there. Human MAIT cells in lung and blood were more homogeneous but still differed between tissues. Human MAIT cells had increased fatty acid uptake and lipid storage in blood and lung, similar to human CD8 T resident memory cells, but unlike mouse MAIT17 cells, they lacked increased mitochondrial potential. Although mouse and human MAIT cell transcriptomes showed similarities for immature cells in the thymus, they diverged more strikingly in the periphery. Analysis of pet store mice demonstrated decreased lung MAIT17 cells in these so-called "dirty" mice, indicative of an environmental influence on MAIT cell subsets and function.

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.