Colorectal cancer (CRC) is the third most common cancer worldwide and has one of the highest mortality rates. Considering its nonlinear etiology, many risk factors are associated with CRC formation and development, with obesity at the forefront. Obesity is regarded as one of the key environmental risk determinants for the pathogenesis of CRC. Excessive food intake and a sedentary lifestyle, together with genetic predispositions, lead to the overgrowth of adipose tissue along with a disruption in the number and function of its building cells. Adipose tissue-resident cells may constitute part of the CRC microenvironment. Alterations in their physiology and secretory profiles observed in obesity may further contribute to CRC progression, and despite similar localization, their contributions are not equivalent. They can interact with CRC cells, either directly or indirectly, influencing various processes that contribute to tumorigenesis. The main aim of this review is to provide insights into the diversity of adipose tissue resident cells, namely, adipocytes, adipose stromal cells, and immunological cells, regarding the role of particular cell types in co-forming the CRC microenvironment. The scope of this study was also devoted to the abnormalities in adipose tissue physiology observed in obesity states and their impact on CRC development.

α-Galactosylceramide (α-GalCer) is a prototypical antigen recognized by natural killer T (NKT) cells, a subset of T cells crucial for immune regulation. Despite its significance, the complex structure-activity relationship of α-GalCer and its analogs remains poorly understood, particularly in defining the structural determinants of NKT cell responses. In this study, we designed and synthesized potential immunomodulatory ligands targeting NKT cells, inspired by glycolipids derived from the gut symbiont Bacteroides fragilis. A series of α-GalCer analogs with terminal iso-branched sphinganine backbones was developed through rational modification of the acyl chain. Our results identified the C3' hydroxyl group as a structural element that impairs glycolipid presentation by CD1d, as evidenced by reduced IL-2 secretion and weak competition with a potent CD1d ligand. Notably, among C3'-deoxy α-GalCer analogs, those containing an α-chloroacetamide group exhibited robust NKT cell activation with Th2 selectivity. Computational docking and mass spectrometry analyses further confirmed the substantial interaction of α-chloroacetamide analogs to CD1d. These findings underscore the potential of leveraging microbiota-derived glycolipid structures to selectively modulate NKT cell functions for therapeutic purposes.

Unconventional T cells, such as invariant natural killer T (iNKT), γδ T, and mucosal-associated invariant T (MAIT) cells, play a pivotal role in bridging innate and adaptive immunity. Their capacity for rapid tumor targeting and effective modulation of the tumor microenvironment (TME) makes them promising candidates for cancer immunotherapy. Advances in chimeric antigen receptor (CAR) engineering have further highlighted their therapeutic potential, particularly for treating challenging cancers. Notably, these cells exhibit favorable safety profiles, enhancing their viability as off-the-shelf therapeutic options. We provide a comprehensive analysis of the clinical applications of CAR-engineered unconventional T cells, focusing on genetic modifications, manufacturing processes, preconditioning regimens, and dosing strategies. We discuss successful examples from recent clinical trials and explore future directions for utilizing these cells in cancer therapy and beyond.

N6-methyladenosine (m6A), a prevalent and essential RNA modification, serves a key function in driving autoimmune disease pathogenesis. By modulating immune cell development, activation, migration, and polarization, as well as inflammatory pathways, m6A is crucial in forming innate defenses and adaptive immunity. This article provides a comprehensive overview of m6A modification features and reveals how its dysregulation affects the intensity and persistence of immune responses, disrupts immune tolerance, exacerbates tissue damage, and promotes the development of autoimmunity. Specific examples include its contributions to systemic autoimmune disorders like lupus and rheumatoid arthritis, as well as conditions that targeting specific organs like multiple sclerosis and type 1 diabetes. Furthermore, this review explores the therapeutic promise of target m6A-related enzymes ("writers," "erasers," and "readers") and summarizes recent advances in intervention strategies. By focusing on the mechanistic and therapeutic implications of m6A modification, this review sheds light on its role as a promising tool for both diagnosis and treatment in autoimmune disorders, laying the foundation for advancements in customized medicine.

Sympathetic nerves innervate bone marrow and various immune organs, where norepinephrine-the primary sympathetic neurotransmitter-directly interacts with immune cells that express adrenergic receptors. This article reviewed the key molecular pathways triggered by sympathetic activation and explored how sympathetic activity influences immune cell migration. Norepinephrine serves as a chemoattractant for monocytes, macrophages, and stem cells, promoting the migration of myeloid cells while inhibiting the migration of lymphocytes at physiological concentrations. We also examined the role of immune cell infiltration in cardiovascular diseases and cancer. Evidence suggests that sympathetic activation increases myeloid cell infiltration into target tissues across various cardiovascular diseases, including atherosclerosis, hypertension, cardiac fibrosis, cardiac hypertrophy, arrhythmia, myocardial infarction, heart failure, and stroke. Conversely, inhibiting sympathetic activity may serve as a potential therapeutic strategy to treat these conditions by reducing macrophage infiltration. Furthermore, sympathetic activation promotes macrophage accumulation in cancer tissues, mirroring its effects in cardiovascular diseases, while suppressing T lymphocyte infiltration into cancerous sites. These changes contribute to increased cancer growth and metastasis. Thus, inhibiting sympathetic activation could help to protect against cancer by enhancing T cell infiltration and reducing macrophage presence in tumors.

Two novel KRN7000 analogues, where d-galactopyranosyl residue was replaced by 5α-gem-difluorocarba-β-l-arabinopyranose, were designed based on docking computation and energy decomposition analyses. The target compounds were synthesized employing the key steps of Ferrier's carbocyclic ring closure and gem-difluoride formation with d-galactose as starting material. The in vivo bioassay revealed that the designed glycolipids could stimulate iNKT cells to produce cytokines IFN-γ and IL-4. The introduced hydroxyl groups on glycolipid acyl chain provided extra CD1d substrate affinities, and thus favored to boost Th1-type cytokine secretion. When the ring oxygen was replaced by CF2 group on sugar unit, its TCR affinities were enhanced in contrast with KRN7000. The in vivo cytokine profiles induced by synthetic glycolipids were initially dominated by the binding ability of CD1/glycolipid, and then adjusted by affinity toward TCR in CD1/α-GalCer/TCR triplex structure. The current results could be helpful in designing of more efficient α-GalCer analogs.

Herpesviruses, including α-herpesvirus and herpes simplex virus (HSV-1), are masters of immune evasion. Previously we demonstrated that CD1d-restricted NKT cells are required for optimal anti-HSV-1 immune responses and HSV-1 efficiently downregulates CD1d to suppress NKT cell function. To delineate how the virus evades NKT cell function and establishes infection in vivo, we screened an HSV-1 expression library to identify the viral gene(s) downregulating CD1d and discovered that a leaky late gene, UL56, most efficiently suppresses CD1d expression by degrading the protein, apparently via both proteasome- and lysosome-dependent pathways. To investigate the molecular mechanism of UL56 suppression of CD1d expression, we purified and identified UL56-associated proteins by mass spectrometry. The most abundant associated proteins were members of NEDD4 E3 ubiquitin ligase family. Interestingly overexpression of one member, NEDD4L is sufficient to downregulate CD1d expression. However, different from the K5 protein from Kaposi sarcoma's herpesvirus (KSHV), UL56 and NEDD4L did not directly ubiquitinate CD1d. CD1d protein lacking the key lysine residue in its cytoplasmic tail is similarly downregulated by UL56 and NEDD4L protein. Co-expression of UL56 and NEDD4L synergistically reduced the CD1d expression, suggesting that UL56 collaborates with NEDD4L to downregulate CD1d. During in vivo infection, UL56-deficient mutant virus showed significantly weaker virulence in NKT-sufficient mice but demonstrated higher virulence in mutant mice lacking NKT cells. All our results supported that at least one of the pathogenesis functions of UL56 is its suppression of NKT cell function during infection.

In the large DNA genomes of herpeviruses, there are many genes encoding associate proteins. Most of these proteins are not essential for viral replication but play key roles in viral pathogenesis, in particular, modulating the host immune system to allow efficient viral replication in vivo and latency. The HSV-1 UL56 gene is one of such genes, and its exact pathogenic roles have remain elusive. After we demonstrated the essential roles of CD1d-restricted NKT cells in anti-HSV-1 immunity during HSV-1 ocular infection (P. Rao, X. Wen, J. H. Lo, S. Kim, X. Li, et al., J Virol 92:e01490-18, 2018, https://doi.org/10.1128/jvi.01490-18), we now screened the HSV-1 expression library and identified UL56 is a key factor downregulating CD1d and suppressing NKT cell function. In this manuscript, we are reporting our molecular mechanism study of how UL56 evades CD1d antigen presentation and NKT cell function.

Invariant Natural Killer T (NKT) cells represent a unique subset of innate-like T cells that express both NK cell and T cell receptors. These cells are rapidly activated by glycolipid antigens presented via CD1d molecules on antigen-presenting cells (APCs), including B cells, dendritic cells (DCs), and macrophages, or through cytokine-dependent mechanisms. Their ability to produce a wide range of cytokines and express costimulatory molecules underscores their critical role in bridging innate and adaptive immunity. B cells, traditionally recognized for their role in antibody production, also act as potent APCs due to their high expression of CD1d, enabling direct interactions with iNKT cells. This interaction has significant implications for humoral immunity, influencing B cell activation, class-switch recombination (CSR), germinal center formation, and memory B cell differentiation, thus expanding the conventional paradigm of T cell-B cell interactions. While the influence of iNKT cells on B cell biology and humoral responses is well-supported, many aspects of their interaction remain unresolved. Key questions include the roles of different iNKT cell subsets, the diversity of APCs, the spatiotemporal dynamics of these interactions, especially during early activation, and the potential for distinct glycolipid ligands to modulate immune outcomes. Understanding these factors could provide valuable insights into how iNKT cells regulate B cell-mediated immunity and offer opportunities to harness these interactions in immunotherapeutic applications, such as vaccine development. In this review, we examine these unresolved aspects and propose a novel perspective on the regulatory potential of iNKT cells in humoral immunity, emphasizing their promise as a target for innovative vaccine strategies.

Invariant natural killer T (iNKT) cells in peripheral tissues are from different waves ranged from foetal, neonatal to adult ages. However, it is unclear how iNKT cells from different ages maintain in the periphery and what are their functionality. We found that in adult mice, neonate tracked-iNKT (NT-iNKT) cells are present in spleen, bone marrow, liver and lung, with a predominantly accumulation in the kidney. The NT-iNKT cells in the kidney are almost iNKT1 cells and express tissue-resident marker CD69. These cells also exhibit higher level of CD122 and possess a stronger proliferative capacity compared to adult tracked-iNKT (AT-iNKT) cells. Furthermore, we found that NT-iNKT cells potentially secrete more IFN-γ than AT-iNKT cells in vitro and in vivo (a-GalCer immunisation). Overall, our study sheds light on the peripheral behaviour and functionality of NT- and AT-iNKT cells, highlighting the potential role of NT-iNKT cells in the kidney during immune response.

In this issue of JEM, Hosono et al. (https://doi.org/10.1084/jem.20240728) characterize a putative self- glycolipid that engages the iNKT cell TCR when bound to CD1d. The expression and distribution of this compound helps to explain some of the unusual properties of invariant NKT cells.

Chimeric antigen receptor (CAR)-engineered T cell therapy holds promise for treating myeloid malignancies, but challenges remain in bone marrow (BM) infiltration and targeting BM-resident malignant cells. Current autologous CAR-T therapies also face manufacturing and patient selection issues, underscoring the need for off-the-shelf products. In this study, we characterize primary patient samples and identify a unique therapeutic opportunity for CAR-engineered invariant natural killer T (CAR-NKT) cells. Using stem cell gene engineering and a clinically guided culture method, we generate allogeneic CD33-directed CAR-NKT cells with high yield, purity, and robustness. In preclinical mouse models, CAR-NKT cells exhibit strong BM homing and effectively target BM-resident malignant blast cells, including CD33-low/negative leukemia stem and progenitor cells. Furthermore, CAR-NKT cells synergize with hypomethylating agents, enhancing tumor-killing efficacy. These cells also show minimal off-tumor toxicity, reduced graft-versus-host disease and cytokine release syndrome risks, and resistance to allorejection, highlighting their substantial therapeutic potential for treating myeloid malignancies.

Invariant Natural Killer T (iNKT) cells are a unique subset of T cells that bridge innate and adaptive immunity, displaying potent anti-tumor properties through cytokine secretion, direct cytotoxicity, and recruitment of immune effector cells such as CD8+ T cells and NK cells. Despite their therapeutic potential, the immunosuppressive tumor microenvironment (TME), characterized by regulatory T cells, myeloid-derived suppressor cells (MDSCs), and tumor-associated macrophages (TAMs), limits iNKT cell efficacy. Patient-derived organoid (PDO) platforms provide an innovative model for dissecting these complex interactions and evaluating strategies to reinvigorate iNKT cell functionality within the TME. PDOs closely mimic the genetic, phenotypic, and structural characteristics of primary tumors, enabling the study of tumor-immune dynamics. Integrating iNKT cells into PDOs offers a robust platform for investigating CD1d-mediated interactions, Th1-biased immune responses driven by glycolipid analogs like α-GalCer, and combination therapies such as immune checkpoint inhibitors. Additionally, PDO systems can assess the effects of metabolic modulation, including reducing lactic acid accumulation or targeting glutamine pathways, on enhancing iNKT cell activity. Emerging innovations, such as organoid-on-a-chip systems, CRISPR-Cas9 gene editing, and multi-omics approaches, further expand the potential of PDO-iNKT platforms for personalized immunotherapy research. Although the application of iNKT cells in PDOs is still undeveloped, these systems hold immense promise for bridging preclinical studies and clinical translation. By addressing the challenges of the TME and optimizing therapeutic strategies, PDO-iNKT platforms offer a transformative avenue for advancing cancer immunotherapy and personalized medicine.

The clinical potential of current chimeric antigen receptor-engineered T (CAR-T) cell therapy is hampered by its autologous nature that poses considerable challenges in manufacturing, costs and patient selection. This spurs demand for off-the-shelf therapies. Here we introduce an ex vivo feeder-free culture method to differentiate gene-engineered hematopoietic stem and progenitor (HSP) cells into allogeneic invariant natural killer T (AlloNKT) cells and their CAR-armed derivatives (AlloCAR-NKT cells). We include detailed information on lentivirus generation and titration, as well as the five stages of ex vivo culture required to generate AlloCAR-NKT cells, including HSP cell engineering, HSP cell expansion, NKT cell differentiation, NKT cell deep differentiation and NKT cell expansion. In addition, we describe procedures for evaluating the pharmacology, antitumor efficacy and mechanism of action of AlloCAR-NKT cells. It takes ~2 weeks to generate and titrate lentiviruses and ~6 weeks to generate mature AlloCAR-NKT cells. Competence with human stem cell and T cell culture, gene engineering and flow cytometry is required for optimal results.

Invariant natural killer T (iNKT) cells are a subset of innate T cells displaying powerful immunomodulatory functions. Despite extensive preclinical research on the use of iNKT agonist and antagonist for various diseases, translating these findings into successful clinical applications has proven challenging, leaving no approved treatments to date. Efforts to optimize therapeutic outcomes by developing alternative glycolipids to α-galactosylceramide (α-GalCer or KRN7000), the prototypical iNKT antigen, have shown improved preclinical results. However, significant obstacles remain, including the relatively laborious synthesis of α-glycosides and their vulnerability to degradation by α-glycosidases. To overcome these limitations, we explored the use of sp2-iminosugars, a class of glycomimetics, to replace the carbohydrate moiety in α-GalCer-like glycolipids. This substitution offers enhanced biostability and precise control over α-selectivity in glycosylation reactions. The resulting sp2-iminoglycolipids (sp2-IGLs) were tested for their immunomodulatory effects, demonstrating the ability to bind the α-GalCer binding site on the CD1d protein in antigen-presenting cells (APCs), and functioning as iNKT antagonists in α-GalCer-stimulated splenocytes. Notably, analogs featuring a 4-alkyl-1,2,3-aminotriazol-1-yl segment in place of the C25N-acyl tail in α-GalCer additionally exhibited mild agonistic activity in the absence of α-GalCer stimulation. Computational studies support the formation of stable CD1d- sp2-IGL and CD1d - sp2-IGL - T-cell receptor complexes, with significant differences in the dynamics depending on the glycone nature and lipid tail length. These findings provide a molecular rationale for the observed experimental data. Furthermore, in vivo studies using murine models of asthma and autoimmune hepatitis have identified promising sp2-IGL candidates for further development in immunotherapy.

MAIT cells are innate-like T cells residing in barrier tissues such as the lung, skin, and intestine. Both the semi-invariant T cell receptor of MAIT cells and the restricting element MR1 are deeply conserved across mammals, indicating non-redundant functions linked to antigenic specificity. MAIT cells across species concomitantly express cytotoxicity and tissue-repair genes, suggesting versatile functions. Accordingly, MAIT cells contribute to antibacterial responses as well as to the repair of damaged barrier tissues. MAIT cells recognize riboflavin biosynthetic pathway-derived metabolites, which rapidly cross epithelial barriers to be presented by antigen-presenting cells. Changes in gut ecology during intestinal inflammation drive the expansion of strong riboflavin and MAIT ligand producers. Thus, MAIT cells may enable real-time surveillance of microbiota dysbiosis across intact epithelia and provide rapid and context-dependent responses. Here, we discuss recent findings regarding the origin and regulation of MAIT ligands and the role of MAIT cells in barrier tissues. We speculate on the potential reasons for MAIT cell conservation during evolution.

In recent years, chimeric antigen receptor (CAR) T-cell therapy has emerged as a groundbreaking approach in cancer immunotherapy. Particularly in hematologic malignancies, such as B-cell acute lymphoblastic leukemia (B-ALL), B cell lymphomas and multiple myeloma. CAR-T therapy has demonstrated remarkable clinical efficacy, leading to the approval of several CAR-T cell products and offering significant benefits to numerous leukemia patients. Despite these successes, the application of CAR-T cells in solid tumors remains limited due to significant challenges, including immunosuppressive tumor microenvironments, heterogeneous antigen expression, and treatment-associated toxicities. In parallel with CAR-T development, researchers are investigating other immune cell platforms to overcome these obstacles. Among these, invariant natural killer T (iNKT) cells have garnered increasing attention for their unique immunological properties. Unlike conventional T cells, iNKT cells are a subset of T lymphocytes characterized by the expression of a semi-invariant T-cell receptor (TCR) that recognizes lipid antigens presented by CD1d molecules. This distinctive antigen recognition mechanism enables iNKT cells to bridge innate and adaptive immunity, granting them potent antitumor activity and the ability to modulate the tumor microenvironment. Additionally, iNKT cells exhibit intrinsic resistance to exhaustion and an enhanced ability to infiltrate solid tumors compared to traditional T cells. Building on these properties, researchers are leveraging CAR technology to enhance iNKT cell tumor-targeting capabilities, aiming to overcome barriers encountered in solid tumor therapy. This review provides an in-depth discussion of the application and therapeutic potential of CAR-iNKT cells in cancer immunotherapy, with a focus on their advantages over conventional CAR-T cells and their role in addressing the challenges of solid tumor treatment.

The controlled release of immunostimulatory agents represents a promising strategy to enhance vaccine efficacy while minimizing side effects. This study aimed to improve the efficacy of the RBD-Fc-based COVID-19 vaccine through combining of an iNKT cell agonist and a TLR7/8 agonist using covalent conjugation and temporal delivery. We hypothesized that these combinations would yield a more balanced Th1/Th2 immune response. For covalent conjugation, we employed an uncleavable linker and a self-immolative disulfide linker to conjugate α-galactosylceramide (αGC) to imidazoquinoline (IMDQ). The αGC-SS-IMDQ-Ac conjugate, designed with a prodrug strategy for controlled TLR7/8 agonist release, elicited a higher IFN-γ/IL-4 T cell response ratio than individual adjuvants or their admixture. In the temporal delivery approach, administering IMDQ followed by αGC after 2 h resulted in the highest IgG2a/IgG1 ratio, significantly surpassing other groups. A 6 h delay between glycolipid and IMDQ injections yielded balanced IgG responses, enhancing IgG, IgG1, and IgG2a levels synergistically.

Mycobacterium tuberculosis causes human tuberculosis (TB). As mycobacteria are protected by a thick lipid cell wall, humans have developed immune responses against diverse mycobacterial lipids. Most of these immunostimulatory lipids are known as adjuvants acting through innate immune receptors, such as C-type lectin receptors. Although a few mycobacterial lipid antigens activate unconventional T cells, the antigenicity of most adjuvantic lipids is unknown. Here, we identified that trehalose monomycolate (TMM), an abundant mycobacterial adjuvant, activated human T cells bearing a unique αβ T cell receptor (αβTCR). This recognition was restricted by CD1b, a monomorphic antigen-presenting molecule conserved in primates but not mice. Single-cell TCR-RNA-Seq using newly established CD1b-TMM tetramers revealed that TMM-specific T cells were present as CD4+ effector memory T cells in the periphery of uninfected donors but expressed IFN-γ, TNF, and anti-mycobacterial effectors upon TMM stimulation. TMM-specific T cells were detected in cord blood and PBMCs of donors without bacillus Calmette-Guérin vaccination but were expanded in patients with active TB. A cryo-electron microscopy study of CD1b-TMM-TCR complexes revealed unique antigen recognition by conserved features of TCRs, positively charged CDR3α, and long CDR3β regions. These results indicate that humans have a commonly shared and preformed CD4+ T cell subset recognizing a typical mycobacterial adjuvant as an antigen. Furthermore, the dual role of TMM justifies reconsideration of the mechanism of action of adjuvants.

In recent years, increasing evidence has highlighted the critical role of myeloid cells, specifically those that present antigen (APCs) in health and disease. These shape the progression and development of neurodegenerative disorders, where considerable interplay between the immune system and neurons influences the course of disease pathogenesis. Antigen-presenting myeloid cells display different classes of major histocompatibility complex (MHC) and MHC-like proteins on their surface for presenting various types of antigens to a wide variety of T cells. While most studies focus on the role of myeloid MHC class I and II molecules in health and disease, there is still much that remains unknown about non-polymorphic MHC-like molecules such as CD1d and MR1. Thus, in this review, we will summarize the recent findings regarding the contributions of both classical and non-classical MHC molecules, particularly on myeloid microglial APCs, in neurodegenerative diseases. This will offer a better understanding of altered mechanisms that may pave the way for the development of novel therapeutic strategies targeting immune cell-MHC interactions, to mitigate neurodegeneration and its associated pathology.

Ten eleven translocation (TET) proteins are tumor suppressors that through their catalytic activity oxidize 5-methylcytosine to 5-hydroxymethylcytosine, to promote DNA demethylation and to regulate gene expression. Notably, TET2 is one of the most frequently mutated genes in hematological malignancies, including T cell lymphomas. However, murine models with deletion of TET2 do not exhibit T cell expansion, presumably due to redundancy with other members of the TET family of proteins. In order to gain insight on the TET mediated molecular events that safeguard T cells from aberrant proliferation we performed serial adoptive transfers of murine CD4 T cells that lack concomitantly TET2 and TET3 to fully immunocompetent congenic mice. Here we show a progressive acquisition of malignant traits upon loss of TET2 and TET3 that is characterized by loss of genomic integrity, acquisition of aneuploidy and upregulation of the protooncogene Myc.

Two major antigen processing pathways represent protein Ags through major histocompatibility complexes (MHC class I and II) or lipid Ags through CD1 molecules influence the tumor immune response. Invariant Natural Killer T cells (iNKT) manage a significant role in cancer immunotherapy. CD1d, found on antigen-presenting cells (APCs), presents lipid Ags to iNKT cells. In many cancers, the number and function of iNKT cell are compromised, leading to immune evasion. Additionally impaired motility of iNKT cells may contribute to poor tumor prognosis. Emerging evidences suggest that CD1d, itself also influences cancer progression. Patient databases further highlight the importance of CD1d expression in different cancers and its correlation with patient survival outcomes. The ability of iNKT cells to activate and enhance the immune response renders them an attractive target for cancer immunotherapy. This review discusses all the possible ways of cancer immune evasion and restoration of immune responses mediated by CD1d-iNKT interactions.

Human natural killer T (NKT) cells have been proposed as a promising cell platform for chimeric antigen receptor (CAR) therapy in solid tumors. Here we generated murine CAR-NKT cells and compared them with CAR-T cells in immune-competent mice. Both CAR-NKT cells and CAR-T cells showed similar antitumor effects in vitro, but CAR-NKT cells showed superior antitumor activity in vivo via CD1d-dependent immune responses in the tumor microenvironment. Specifically, we show that CAR-NKT cells eliminate CD1d-expressing M2-like macrophages. In addition, CAR-NKT cells promote epitope spreading and activation of endogenous T cell responses against tumor-associated neoantigens. Finally, we observed that CAR-NKT cells can co-express PD1 and TIM3 and show an exhaustion phenotype in a model of high tumor burden. PD1 blockade as well as vaccination augmented the antitumor activity of CAR-NKT cells. In summary, our results demonstrate the multimodal function of CAR-NKT cells in solid tumors, further supporting the rationale for developing CAR-NKT therapies in the clinic.

The expression of thyroid-stimulating hormone receptor (TSHR) has been documented on various immune cells, including B lymphocytes, T lymphocytes, Natural Killer (NK) cells, monocytes, and dendritic cells (DCs). Natural Killer T (NKT) cells serve as a crucial link between innate and adaptive immunity, playing significant roles in immunological interactions and autoimmune diseases. The aim of the present study was to evaluate the presence of TSHR on NKT cells. Our research involved patients with thyroid disease, as well as healthy controls. Peripheral blood mononuclear cells (PBMCs) and, thereafter, NKT cells were isolated from 86 patients with benign nodular thyroid disease with and without autoimmune thyroid disease (AITD) (28 and 56 cases, respectively), and TSHR expression was analyzed using fluorescence-activated cell sorting (FACS). In order to confirm the results, the reverse-transcription polymerase chain reaction (RT-PCR) method was used in cells obtained from healthy individuals. Our findings obtained with application of the FACS method revealed that TSHR is not expressed on NKT cells in either AITD or non-AITD patients, though TSHR was detected in the total PBMC population (TSHR+ cells 2.77%). The absence of TSHR on NKT cells was further confirmed with RT-PCR in healthy individuals (p < 0.0001). These results questioned the previously suggested direct influence of NKT cells on AITD development.

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.

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.

The innate immune system serves as the body's first line of defense, utilizing pattern recognition receptors like Toll-like receptors to detect pathogens and initiate rapid response mechanisms. Following this initial response, adaptive immunity provides highly specific and sustained killing of pathogens via B cells, T cells, and antibodies. Traditionally, it has been assumed that innate immunity activates adaptive immunity; however, recent studies have revealed more complex interactions. This review provides a detailed dissection of the composition and function of the innate and adaptive immune systems, emphasizing their synergistic roles in physiological and pathological contexts, providing new insights into the link between these two forms of immunity. Precise regulation of both immune systems at the same time is more beneficial in the fight against immune-related diseases, for example, the cGAS-STING pathway has been found to play an important role in infections and cancers. In addition, this paper summarizes the challenges and future directions in the field of immunity, including the latest single-cell sequencing technologies, CAR-T cell therapy, and immune checkpoint inhibitors. By summarizing these developments, this review aims to enhance our understanding of the complexity interactions between innate and adaptive immunity and provides new perspectives in understanding the immune system.

Human T cell leukemia virus type 1 (HTLV-1) is the first human oncogenic retrovirus to be discovered and causes two major diseases: a progressive neuro-inflammatory disease, termed HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), and an aggressive malignancy of T lymphocytes known as adult T cell leukemia (ATL). Innate and acquired immune responses play pivotal roles in controlling the status of HTLV-1-infected cells and such, the outcome of HTLV-1 infection. Natural killer cells (NKCs) are the effector cells of the innate immune system and are involved in controlling viral infections and several types of cancers. The ability of NKCs to trigger cytotoxicity to provide surveillance against viruses and cancer depends on the balance between the inhibitory and activating signals. In this review, we will discuss NKC function and the alterations in the frequency of these cells in HTLV-1 infection.

This Optimized Multiparameter Immunofluorescence Panel (OMIP) reports on the development of a mass cytometry panel for broad immunophenotyping of leukocytes from bronchoalveolar lavage from rhesus macaques. Using this panel, we were able to identify myeloid populations such as macrophages, neutrophils, monocytes, myeloid and plasmacytoid DCs, basophils and lymphoid cell lineages including B cells, natural killer (NK) cells, mucosal associated invariant T (MAIT) cells, γδ T cells, CD4 T cells, CD8 β T cells, CD8 T cells, and innate lymphoid cells (ILCs). We also included markers for defining memory, differentiation (CCR7, CD28, CD45RA), homing potential (CXCR3), cytotoxic potential (perforin, granzyme B, granzyme K), cell activation/differentiation (HLA-DR, CD69, IgD) and effector function (CD154, IFN-γ, TNF, IL-2, IL-17A, IL-6, IL-1β, CCL4 and CD107a). This panel was optimized on cryopreserved, bronchoalveolar lavage and splenocytes collected from rhesus macaques. The antibodies selected in this panel are human-specific antibodies that have been shown to cross-react with non-human primates except for CD45 clone D058-1283 which is specific for non-human primates.

Polycomb repressive complex 2 (PRC2) is an evolutionarily conserved epigenetic modifier responsible for tri-methylation of lysine 27 on histone H3 (H3K27me3). Previous studies have linked PRC2 to invariant natural killer T (iNKT) cell development, but its physiological and precise role remained unclear. To address this, we conditionally deleted Eed, a core subunit of PRC2, in mouse T cells. The results showed that Eed-deficient mice exhibited a severe reduction in iNKT cell numbers, particularly NKT1 and NKT17 cells, while conventional T cells and NKT2 cells remained intact. Deletion of Eed disrupted iNKT cell differentiation, leading to increased cell death, which was accompanied by a severe reduction in H3K27me3 levels and abnormal expression of Zbtb16, Cdkn2a, and Cdkn1a. Interestingly, Eed-deficient mice were highly susceptible to acetaminophen-induced liver injury and inflammation in an iNKT cell-dependent manner, highlighting the critical role of Eed-mediated H3K27me3 marks in liver-resident iNKT cells. These findings provide further insight into the epigenetic orchestration of iNKT cell-specific transcriptional programs.

DNA demethylases TET2 and TET3 play a fundamental role in thymic invariant natural killer T (iNKT) cell differentiation by mediating DNA demethylation of genes encoding for lineage specifying factors. Paradoxically, differential gene expression analysis revealed that significant number of genes were upregulated upon TET2 and TET3 loss in iNKT cells. This unexpected finding could be potentially explained if loss of TET proteins was reducing the expression of proteins that suppress gene expression. In this study, we discover that TET2 and TET3 synergistically regulate Drosha expression, by generating 5hmC across the gene body and by impacting chromatin accessibility. As DROSHA is involved in microRNA biogenesis, we proceed to investigate the impact of TET2/3 loss on microRNAs in iNKT cells. We report that among the downregulated microRNAs are members of the Let-7 family that downregulate in vivo the expression of the iNKT cell lineage specifying factor PLZF. Our data link TET proteins with microRNA expression and reveal an additional layer of TET mediated regulation of gene expression.

Invariant natural killer T (iNKT) cells are glycolipid-reactive T cells with potent immunoregulatory properties. iNKT cells activated with the marine-sponge-derived glycolipid, α-galactosylceramide (αGC), provide a universal source of T-cell help that has shown considerable promise for a wide array of therapeutic applications. This includes harnessing iNKT-cell-mediated immune responses to adjuvant whole inactivated influenza virus (WIV) vaccines. An important concern with WIV vaccines is that under certain circumstances, they are capable of triggering vaccine-associated enhanced respiratory disease (VAERD). This immunopathological phenomenon can arise after immunization with an oil-in-water (OIW) adjuvanted WIV vaccine, followed by infection with a hemagglutinin and neuraminidase mismatched challenge virus. This elicits antibodies (Abs) that bind immunodominant epitopes in the HA2 region of the heterologous virus, which purportedly causes enhanced virus fusion activity to the host cell and increased infection. Here, we show that αGC can induce severe VAERD in pigs. However, instead of stimulating high concentrations of HA2 Abs, αGC elicits high concentrations of interferon (IFN)-γ-secreting cells both in the lungs and systemically. Additionally, we found that VAERD mediated by iNKT cells results in distinct cytokine profiles and altered adaptation of the challenge virus following infection compared to an OIW adjuvant. Overall, these results provide a cautionary note about considering the formulation of WIV vaccines with iNKT-cell agonists as a potential strategy to modulate antigen-specific immunity.

T-cell immunoglobulin and mucin domain-containing molecule 4 (Tim-4) is an immune checkpoint molecule, which involves in numerous inflammatory diseases. Tim-4 is mainly expressed on antigen-presenting cells. However, increasing evidence has shown that Tim-4 is also expressed on natural killer T (NKT) cells. The role of Tim-4 in maintaining NKT cell homeostasis and function remains unknown. In this study, we explored the effect of Tim-4 on NKT cells in acute liver injury. This study found that Tim-4 expression on hepatic NKT cells was elevated during acute liver injury. Tim-4 deficiency enhanced IFN-γ, TNF-α expression while impaired IL-4 production in NKT cells. Loss of Tim-4 drove NKT-cell effector lineages to be skewed to NKT1 subset. Furthermore, Tim-4 KO mice were more susceptible to α-Galactosylceramide (α-GalCer) challenge. In conclusion, our findings indicate that Tim-4 plays an important role in regulating homeostasis and function of NKT cells in acute liver injury. Therefore, Tim-4 might become a new regulator of NKT cells and a potential target for the therapy of acute hepatitis.

Antioxidant supplementation in critical periods may be useful for improvement of piglet early viability and development. We have evaluated the effects of maternal perinatal diet inclusion of a high vitamin E level (VE, 100 mg all-rac-α-tocopheryl acetate /kg), hydroxytyrosol (HT, 1.5 mg/kg), or their combination (VEHT), in comparison to a control diet (C, 30 mg all-rac-α-tocopheryl acetate /kg), on the offspring homeostasis and metabolism, analysing the weaned piglets' adipose tissue transcriptome and adipocyte morphology. Diets were provided to pregnant Iberian sows (n = 48, 12 per treatment) from gestation day 85 to weaning (28 days postpartum) and 48 piglets (n = 12 per treatment) were sampled 5 days postweaning for dorsal subcutaneous adipose tissue analyses. RNA obtained from 6 animals for each diet was used for paired-end RNA sequencing. Results show that supplementation of sows' diet with either vitamin E or hydroxytyrosol had substantial effects on weaned piglet adipose transcriptome, with 664 and 587 genes being differentially expressed, in comparison to C, respectively (q-value<0.10, Fold Change>1.5). Genes upregulated in C were mainly involved in inflammatory and immune response, as well as oxidative stress, and relevant canonical pathways and upstream regulators involved in these processes were predicted as activated, such as TNF, IFNB or NFKB. Vitamin E, when supplemented alone at high dose, activated lipid biosynthesis functions, pathways and regulators, this finding being accompanied by increased adipocyte size. Results suggest an improved metabolic and antioxidant status of adipose tissue in animals born from sows supplemented with individual antioxidants, while the combined supplementation barely affected gene expression, with VEHT showing a prooxidant/proinflamatory functional profile similar to C animals. Different hypothesis are proposed to explain this unexpected result. Findings allow a deeper understanding of the processes taking place in adipose tissue of genetically fat animals and the role of antioxidants in the regulation of fat cells function.

Numerous developments have been achieved in the study and treatment of cancer throughout the decades that it has been common. After decades of research, about 100 different kinds of cancer have been found, each with unique subgroups within certain organs. This has significantly expanded our understanding of the illness. A mix of genetic, environmental, and behavioral variables contribute to the complicated and diverse process of cancer formation. Mutations, or changes in the DNA sequence, are crucial to the development of cancer. These mutations have the ability to downregulate the expression and function of Major Histocompatibility Complex class I (MHC I) and MHCII receptors, as well as activate oncogenes and inactivate tumor suppressor genes. Cancer cells use this tactic to avoid being recognized by cytotoxic CD8+T lymphocytes, which causes issues with antigen presentation and processing. This review goes into great length into the PI3K pathway, changes to MHC I, and positive impacts of tsMHC-II on disease-free survival and overall survival and the involvement of dendritic cells (DCs) in different tumor microenvironments. The vital functions that the PI3K pathway and its link to the mTOR pathway are highlighted and difficulties in developing effective cancer targeted therapies and feedback systems has also been mentioned, where resistance mechanisms include RAS-mediated oncogenic changes and active PI3K signalling.

CD1 isoforms are MHC class I-like molecules that present lipid-antigens to T cells and have been associated with a variety of immune responses. The lipid repertoire bound and presented by the four CD1 isoforms may be influenced by factors such as the cellular lipidome, subcellular microenvironment, and the properties of the binding pocket. In this study, by shotgun mass spectrometry, we performed a comprehensive lipidomic analysis of soluble CD1 molecules. We identified 1040 lipids, of which 293 were present in all isoforms. Comparative analysis revealed that the isoforms bind almost any cellular lipid.CD1a and CD1c closely mirrored the cellular lipidome, while CD1b and CD1d showed a preference for sphingolipids. Each CD1 isoform was found to have unique lipid species, suggesting some distinct roles in lipid presentation and immune responses. These findings contribute to our understanding of the role of CD1 system in immunity and could have implications for the development of lipid-based therapeutics.

A dysregulated immune system is a major driver of the mortality and long-term morbidity from sepsis. With respect to macrophages, it has been shown that phenotypic changes are critical to effector function in response to acute infections, including intra-abdominal sepsis. Invariant natural killer T cells (iNKT cells) have emerged as potential central regulators of the immune response to a variety of infectious insults. Specifically, various iNKT cell:macrophage interactions have been noted across a spectrum of diseases, including acute events such as sepsis. However, the potential for iNKT cells to affect peritoneal macrophages during an abdominal septic event is as yet unknown.

Cecal ligation and puncture (CLP) was performed in both wild type (WT) and invariant natural killer T cell knockout (iNKT-/-) mice. 24 h following CLP or sham operation, peritoneal macrophages were collected for analysis. Analysis of macrophage phenotype and function was undertaken to include analysis of bactericidal activity and cytokine or superoxide production.

Within iNKT-/- mice, a greater degree of intraperitoneal macrophages in response to the sepsis was noted. Compared to WT mice, within iNKT-/- mice, CLP did induce an increase in CD86+ and CD206+, but no difference in CD11b+. Unlike WT mice, intra-abdominal sepsis within iNKT-/- mice induced an increase in Ly6C-int (5.2% versus 14.9%; P < 0.05) and a decrease in Ly6C-high on peritoneal macrophages. Unlike phagocytosis, iNKT cells did not affect macrophage bactericidal activity. Although iNKT cells did not affect interleukin-6 production, iNKT cells did affect IL-10 production and both nitrite and superoxide production from peritoneal macrophages.

The observations indicate that iNKT cells affect specific phenotypic and functional aspects of peritoneal macrophages during polymicrobial sepsis. Given that pharmacologic agents that affect iNKT cell functioning are currently in clinical trial, these findings may have the potential for translation to critically ill surgical patients with abdominal sepsis.

Pancreatic ductal adenocarcinoma (PDA) is a potentially lethal disease lacking effective treatments. Its immunosuppressive tumor microenvironment (TME) allows it to evade host immunosurveillance and limits response to immunotherapy. Here, using the mouse KRT19-deficient (sgKRT19-edited) PDA model, we find that intratumoral accumulation of natural killer T (NKT) cells is required to establish an immunologically active TME. Mechanistically, intratumoral NKT cells facilitate type I interferon (IFN) production to initiate an antitumor adaptive immune response, and orchestrate the intratumoral infiltration of T cells, dendritic cells, natural killer cells, and myeloid-derived suppressor cells. At the molecular level, NKT cells promote the production of type I IFN through the interaction of their CD40L with CD40 on myeloid cells. To evaluate the therapeutic potential of these observations, we find that administration of folinic acid to mice bearing PDA increases NKT cells in the TME and improves their response to anti-PD-1 antibody treatment. In conclusion, NKT cells have an essential role in the immune response to mouse PDA and are potential targets for immunotherapy.