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Summary After traumatic injury, some cells function as detectors to sense injury and to modulate the local immune response toward a restitution phase by affecting the local cytokine milieu. Using intravital microscopy, we observed that patrolling invariant natural killer T (iNKT) cells were initially excluded from a site of hepatic injury but subsequently were strategically arrested first via self-antigens and then by cytokines, circumscribing the injured site at exactly the location where monocytes co-localized and hepatocytes proliferated. Activation of iNKT cells by self-antigens resulted in the production of interleukin-4 (IL-4) but not interferon-γ (IFN-γ). This promoted increased hepatocyte proliferation, monocyte transition (from Ly6C hi to Ly6C lo ), and improved healing where IL-4 from iNKT cells was critical for these processes. Disruption of any of these mechanisms led to delayed wound healing. We have shown that self-antigen-driven iNKT cells function as sensors and orchestrators of the transformation from inflammation to tissue restitution for essential timely wound repair. [ABSTRACT FROM AUTHOR]

Background: The chemokine X-C motif chemokine ligand 1 (XCL1)-X-C motif chemokine receptor 1 (XCR1) axis has been reported to play a role in immune homeostasis and inflammation. However, it is not known whether this axis has a critical function in patients with allergic asthma., Objective: In the present study we explored whether the invariant natural killer T (iNKT) cell-mediated XCL1-XCR1 axis regulated allergic asthma., Methods: Ovalbumin (OVA)- or house dust mite-induced asthma was developed in XCL1 or XCR1 knockout (KO) mice., Results: XCL1 or XCR1 KO mice showed attenuation in airway hyperresponsiveness (AHR), numbers of CD103 + dendritic cells (DCs), and T H 2 responses in the lungs compared with wild-type (WT) mice during OVA- or house dust mite-induced asthma. These effects were reversed by intratracheal administration of recombinant XCL1 or adoptive transfer of CD103 + DCs but not CD11b + DCs into XCL1 KO mice. Moreover, iNKT cells highly expressed XCL1 both in vitro and in vivo. On intranasal α-galactosyl ceramide challenge, CD103 + DC numbers in the lungs were increased in WT but not XCL1 KO mice. Furthermore, adoptive transfer of WT iNKT cells increased AHR, CD103 + DC recruitment, and T H 2 responses in the lungs of CD1d KO mice during OVA-induced asthma, whereas adoptive transfer of XCL1-deficient iNKT cells did not. In human patients, percentages and XCL1 production capacity of iNKT cells from PBMCs were greater in patients with asthma than in healthy control subjects., Conclusion: These data demonstrate that the iNKT cell-mediated XCL1-XCR1 axis promotes AHR by recruiting CD103 + DCs into the lung in patients with allergic asthma., (Copyright © 2018 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Background: Store-operated Ca 2+ entry (SOCE) through Ca 2+ release-activated Ca 2+ channels is an essential signaling pathway in many cell types. Ca 2+ release-activated Ca 2+ channels are formed by ORAI1, ORAI2, and ORAI3 proteins and activated by stromal interaction molecule (STIM) 1 and STIM2. Mutations in the ORAI1 and STIM1 genes that abolish SOCE cause a combined immunodeficiency (CID) syndrome that is accompanied by autoimmunity and nonimmunologic symptoms., Objective: We performed molecular and immunologic analysis of patients with CID, anhidrosis, and ectodermal dysplasia of unknown etiology., Methods: We performed DNA sequencing of the ORAI1 gene, modeling of mutations on ORAI1 crystal structure, analysis of ORAI1 mRNA and protein expression, SOCE measurements, immunologic analysis of peripheral blood lymphocyte populations by using flow cytometry, and histologic and ultrastructural analysis of patient tissues., Results: We identified 3 novel autosomal recessive mutations in ORAI1 in unrelated kindreds with CID, autoimmunity, ectodermal dysplasia with anhidrosis, and muscular dysplasia. The patients were homozygous for p.V181SfsX8, p.L194P, and p.G98R mutations in the ORAI1 gene that suppressed ORAI1 protein expression and SOCE in the patients' lymphocytes and fibroblasts. In addition to impaired T-cell cytokine production, ORAI1 mutations were associated with strongly reduced numbers of invariant natural killer T and regulatory T (Treg) cells and altered composition of γδ T-cell and natural killer cell subsets., Conclusion: ORAI1 null mutations are associated with reduced numbers of invariant natural killer T and Treg cells that likely contribute to the patients' immunodeficiency and autoimmunity. ORAI1-deficient patients have dental enamel defects and anhidrosis, representing a new form of anhidrotic ectodermal dysplasia with immunodeficiency that is distinct from previously reported patients with anhidrotic ectodermal dysplasia with immunodeficiency caused by mutations in the nuclear factor κB signaling pathway (IKBKG and NFKBIA)., (Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

We have exploited the properties of filamentous bacteriophage fd to deliver immunologically active lipids together with antigenic peptides. Filamentous bacteriophages resemble for size, capability to be permeable to blood vessels, and high density antigen expression, a nature-made nanoparticle. In addition, their major coat protein pVIII, which is arranged to form a tubular shield surrounding the phage genome, has a high content of hydrophobic residues promoting lipid association. We conjugated bacteriophages to alpha-GalactosylCeramide (α-GalCer), a lipid antigen-stimulating invariant natural killer T (iNKT) cells and capable of inducing their anti-tumoral activities. We found that bacteriophage fd/α-GalCer conjugates could repeatedly stimulate iNKT cells in vitro and in vivo , without inducing iNKT anergy. Moreover, co-delivery of α-GalCer and a MHC class I restricted tumor-associated antigenic determinant to antigen-presenting cells via bacteriophages strongly boosted adaptive CD8 + T cell response and efficiently delayed tumor progression. Co-delivery of a tumor antigen and iNKT-stimulatory lipid on the surface of filamentous bacteriophages is a novel approach to potentiate adaptive anti-cancer immune responses, overcoming the current limitations in the use of free α-GalCer and may represent an attractive alternative to existing delivery methods, opening the path to a potential translational usage of this safe, inexpensive, and versatile tool.

Increasing drug resistance and the lack of an effective vaccine are the main factors contributing to Mycobacterium tuberculosis (Mtb) being a major cause of death globally. Despite intensive research efforts, it is not well understood why some individuals control Mtb infection and some others develop active disease. HIV-1 infection is associated with an increased incidence of active tuberculosis, even in virally suppressed individuals. Mucosal-associated invariant T (MAIT) and invariant natural killer T (iNKT) cells are innate T cells that can recognize Mtb-infected cells. Contradicting results regarding the frequency of MAIT cells in latent Mtb infection have been reported. In this confirmatory study, we investigated the frequency, phenotype, and IFNγ production of MAIT and iNKT cells in subjects with latent or active Mtb infection. We found that the frequency of both cell types was increased in subjects with latent Mtb infection compared with uninfected individuals or subjects with active infection. We found no change in the expression of HLA-DR, PD-1, and CCR6, as well as the production of IFNγ by MAIT and iNKT cells, among subjects with latent Mtb infection or uninfected controls. The proportion of CD4- CD8+ MAIT cells in individuals with latent Mtb infection was, however, increased. HIV-1 infection was associated with a loss of MAIT and iNKT cells, and the residual cells had elevated expression of the exhaustion marker PD-1. Altogether, the results suggest a role for MAIT and iNKT cells in immunity against Mtb and show a deleterious impact of HIV-1 infection on those cells.

CD1d-restricted invariant natural killer T (iNKT) cells play central roles in the activation and regulation of innate and adaptive immunity. Cytokine-mediated and CD1d-dependent interactions between iNKT cells and myeloid and lymphoid cells enable iNKT cells to contribute to the activation of multiple cell types, with important impacts on host immunity to infection and tumors and on the prevention of autoimmunity. Here, we review the mechanisms by which iNKT cells contribute to B cell maturation, antibody and cytokine production, and antigen presentation. Cognate interactions with B cells contribute to the rapid production of antibodies directed against conserved non-protein antigens resulting in rapid but short-lived innate humoral immunity. iNKT cells can also provide non-cognate help for the generation of antibodies directed against protein antigens, by promoting the activation of follicular helper T cells, resulting in long-lasting adaptive humoral immunity and B cell memory. iNKT cells can also regulate humoral immunity by promoting the development of autoreactive B cells into regulatory B cells. Depletions and functional impairments of iNKT cells are found in patients with infectious, autoimmune and malignant diseases associated with altered B cell function and in murine models of these conditions. The adjuvant and regulatory activities that iNKT cells have for B cells makes them attractive therapeutic targets for these diseases.

Adipose tissue is a metabolic organ that plays a central role in controlling systemic energy homeostasis. Compelling evidence indicates that immune system is closely linked to healthy physiologic functions and pathologic dysfunction of adipose tissue. In obesity, the accumulation of pro-inflammatory responses in adipose tissue subsequently leads to dysfunction of adipose tissue as well as whole body energy homeostasis. Simultaneously, adipose tissue also activates anti-inflammatory responses in an effort to reduce the unfavorable effects of pro-inflammation. Notably, the interplay between adipocytes and resident invariant natural killer T (iNKT) cells is a major component of defensive mechanisms of adipose tissue. iNKT cells are leukocytes that recognize lipids loaded on CD1d as antigens, whereas most other immune cells are activated by peptide antigens. In adipose tissue, adipocytes directly interact with iNKT cells by presenting lipid antigens and stimulate iNKT cell activation to alleviate pro-inflammation. In this review, we provide an overview of the molecular and cellular determinants of obesity-induced adipose tissue inflammation. Specifically, we focus on the roles of iNKT cell-adipocyte interaction in maintaining adipose tissue homeostasis as well as the consequent modulation in systemic energy metabolism. We also briefly discuss future research directions regarding the interplay between adipocytes and adipose iNKT cells in adipose tissue inflammation.

Gout is an inflammatory arthritis caused by deposition of intra-articular monosodium urate (MSU) crystal. Previous studies have focused on resident macrophage, infiltrating monocyte, and neutrophil responses to MSU crystal; yet the mechanisms of cellular changes and the potential involvement of other regulatory immune cells remain largely unknown. Invariant natural killer T ( i NKT) cells, an innate type of T cell, are involved in the development of various inflammatory diseases. Here, we investigate the role of i NKT cells in MSU crystal-induced gouty inflammation. MSU crystal-induced inflammatory profiles in an air-pouch model were examined in i NKT-deficient CD1d knockout (KO) and wild-type (WT) control mice. To explore potential mechanisms of i NKT cell regulation of gouty inflammation, we cocultured CD4 + or CD4 - i NKT cells with bone marrow-derived macrophages (BMDMs). We found that i NKT cells quickly migrated to the site of inflammation upon MSU crystal stimulation in WT mice. The total number of infiltrating cells in CD1d KO mice, especially neutrophils, was dramatically increased at 6 and 12 h ( P  < 0.01) post-MSU crystal challenge, compared with WT controls. BMDMs cocultured with CD4 + i NKT cells produced less tumor necrosis factor-α and expressed higher levels of M2 macrophage markers, including Clec7a, Pdcd1Ig2, and interleukin-4 ( P  < 0.01), compared with BMDMs cocultured with CD4 - i NKT cells or conventional CD4 + T cells. CD4 + i NKT cells are one of the key regulators of MSU crystal-induced gouty inflammation through the control of macrophage polarization. i NKT cells may serve as a new therapeutic target for gout.

Background: Histamine is a key immunoregulatory mediator and can dampen proinflammatory responses via activation of histamine receptor 2 (H 2 R). The aim of this study was to determine the role of H 2 R in modulating lung inflammatory responses., Methods: H 2 R was blocked using famotidine or activated using dimaprit in both the ovalbumin (OVA) and house dust mite extract (HDM) murine models of respiratory inflammation. H 2 R-deficient animals and CD1d/H 2 R-deficient animals were utilized to examine the CD1d presentation of lipid antigens (αGalCer or OCH) to invariant natural killer T (iNKT) cells., Results: Famotidine treatment resulted in more severe airway disease in the OVA model, while dimaprit treatment significantly reduced disease severity. Both OVA and HDM-induced airway diseases were more severe in H 2 R-deficient animals. Flow cytometric analysis of lung tissue from H 2 R-deficient animals revealed increased numbers of CD1d + dendritic cells and increased numbers of iNKT cells. In vitro, αGalCer-stimulated iNKT cells from H 2 R-deficient mice secreted higher levels of IL-4, IL-5, and GM-CSF. In vivo, αGalCer or OCH administration to the lung resulted in enhanced mucus secretion, inflammatory cell recruitment, and cytokine production in H 2 R-deficient or famotidine-treated animals, while dimaprit dampened the lung iNKT cell response to αGalCer. Removal of iNKT cells in H 2 R-deficient (CD1d -/- H 2 R -/- ) animals normalized the lung response to HDM., Conclusion: The deliberate activation of H 2 R, or its downstream signaling molecules, may represent a novel therapeutic target for chronic lung inflammatory diseases, especially when CD1d-mediated presentation of lipid antigens to iNKT cells is contributing to the pathology., (© 2017 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.)

We have shown that invariant natural killer T ( i NKT) cells mediate sepsis-induced end-organ changes and immune responses, including macrophage bacterial phagocytosis, a finding regulated by the check point protein program cell death receptor-1 (PD-1). Furthermore, PD-1 mediates mortality in both adult and neonatal murine sepsis as well as in surgical patients. Given our previous findings, we hypothesize that i NKT cells will also modulate neonatal sepsis survival, and that this effect is regulated in part through PD-1. We utilized a polymicrobial intra-peritoneal cecal slurry (CS) sepsis model in wild type (WT), i NKT -/- or PD-1 -/- 5-7 day old neonatal pups. Typically, tissues were harvested at 24 h for various bioassays/histology and, in some cases, survival was assessed for up to 7 days. Interestingly, similar to what we recently reported for PD-1 -/- mice following CS, i NKT -/- -deficient animals exhibit a markedly improved survival vs. WT. Histologically, minor alterations in liver architectural, which were noted in WT pups, were attenuated in both i NKT -/- and PD-1 -/- pups. Following CS, PECAM-1 expression was unchanged in the WT pups but increased in both i NKT -/- and PD-1 -/- pups. In WT, following CS the emergence of a Ly6C low subpopulation was noted among the influxed peritoneal macrophage population. Conversely, within i NKT -/- pups, there were fewer peritoneal macrophages and a greater percentage of Ly6C high macrophages. We show not only a key role for i NKT cells in affecting end-organ damage as well as alterations in phagocytes phenotypes in neonatal sepsis but that this i NKT cell mediated effect is driven by the central checkpoint protein PD-1.

The role of sphingolipids (SLs) in the immune system has come under increasing scrutiny recently due to the emerging contributions that these important membrane components play in regulating a variety of immunological processes. The acyl chain length of SLs appears particularly critical in determining SL function. Here, we show a role for very-long acyl chain SLs (VLC-SLs) in invariant natural killer T ( i NKT) cell maturation in the thymus and homeostasis in the liver. Ceramide synthase 2-null mice, which lack VLC-SLs, were susceptible to a hepatotropic strain of lymphocytic choriomeningitis virus, which is due to a reduction in the number of i NKT cells. Bone marrow chimera experiments indicated that hematopoietic-derived VLC-SLs are essential for maturation of i NKT cells in the thymus, whereas parenchymal-derived VLC-SLs are crucial for i NKT cell survival and maintenance in the liver. Our findings suggest a critical role for VLC-SL in i NKT cell physiology.

Background: Cow milk (CM) allergy (CMA) affects up to 3% of the paediatric population and recent data suggest that only about 50% will outgrow by age 8. Oral immunotherapy (OIT) is a type of immune-modulating treatment that is able to induce desensitization to food allergens, to increase tolerance threshold, to reduce the risk of anaphylaxis, and to improve the patient's quality of life. The examination of the immunological changes observed during the establishment of food allergy (FA) desensitization in FA patients is a window into the pathogenesis of food allergy and food tolerance development. In this pathway, we have previously found that invariant natural killer T cells (iNKTs) are involved in CM allergy sensitization and now examine their role in OIT., Methods: In this study, 10 of the 11 children with CM induced anaphylaxis enrolled in a CMA OIT clinical trial and completed the protocol. Peripheral blood iNKTs were quantitatively and qualitatively via flow cytometry characterized ex vivo and after culture with milk lipids before and after completing the OIT protocol., Results: After completing OIT for CM, children were able to reintroduce CM in their diet. For the first time, we demonstrated that OIT induced a significant increase in the peripheral blood iNKT, as well as their switch from a T helper (Th-2; ie IL-4, IL-13) to Th-1 (ie IFN-γ) cytokine profile., Conclusions and Clinical Relevance: This study confirms the efficacy and safety of CM-OIT as well as the role of iNKT cells in CM allergy., (© 2017 John Wiley & Sons Ltd.)

We and others have found that the functions of hepatic natural killer (NK) cells are inhibited but invariant NKT (iNKT) cells become activated after alcohol drinking, leaving a possibility that there exists interplay between NK cells and iNKT cells during alcoholic liver disease. Here, in a chronic plus single-binge ethanol consumption mouse model, we observed that NK cells and interferon-γ (IFN-γ) protected against ethanol-induced liver steatosis, as both wild-type (WT) mice treated with anti-asialo GM1 antibody and IFN-γ-deficient GKO mice developed more severe alcoholic fatty livers. As expected, IFN-γ could directly downregulate lipogenesis in primary hepatocytes in vitro . On the contrary, iNKT cell-deficient Jα18 -/- or interleukin-10 (IL-10) -/- mice showed fewer alcoholic steatosis, along with the recovered number and IFN-γ release of hepatic NK cells, and exogenous IL-10 injection was sufficient to compensate for iNKT cell deficiency. Furthermore, NK cell depletion in Jα18 -/- or IL-10 -/- mice caused more severe hepatosteatosis, implying NK cells are the direct effector cells to inhibit liver steatosis. Importantly, adoptive transfer of iNKT cells purified from normal but not IL-10 -/- mice resulted in suppression of the number and functions of NK cells and aggravated alcoholic liver injury in Jα18 -/- mice, indicating that IL-10-producing iNKT (NKT10) cells are the regulators on NK cells. Conclusion : Ethanol exposure-triggered NKT10 cells antagonize the protective roles of NK cells in alcoholic hepatosteatosis.

c-Maf belongs to the large Maf family of transcription factors and plays a key role in the regulation of cytokine production and differentiation of T H 2, T H 17, T FH , and Tr1 cells. Invariant natural killer T (iNKT) cells can rapidly produce large quantity of T H -related cytokines such as IFN-γ, IL-4, and IL-17A upon stimulation by glycolipid antigens, such as α-galactosylceramide (α-GalCer). However, the role of c-Maf in iNKT cells and iNKT cells-mediated diseases remains poorly understood. In this study, we demonstrate that α-GalCer-stimulated iNKT cells express c-Maf transcript and protein. By using c-Maf-deficient fetal liver cell-reconstituted mice, we further show that c-Maf-deficient iNKT cells produce less IL-17A than their wild-type counterparts after α-GalCer stimulation. While c-Maf deficiency does not affect the development and activation of iNKT cells, c-Maf is essential for the induction of IL-17-producing iNKT (iNKT17) cells by IL-6, TGF-β, and IL-1β, and the optimal expression of RORγt. Accordingly, c-Maf-deficient iNKT17 cells lose the ability to recruit neutrophils into the lungs. Taken together, c-Maf is a positive regulator for the expression of IL-17A and RORγt in iNKT17 cells. It is a potential therapeutic target in iNKT17 cell-mediated inflammatory disease.

The ubiquitously expressed tyrosine phosphatase Src homology region 2 domain-containing phosphatase-2 (SHP-2, encoded by Ptpn11 ) is required for constitutive cellular processes including proliferation, differentiation, and the regulation of immune responses. During development and maturation, subsets of T cells express a variety of inhibitory receptors known to associate with phosphatases, which in turn, dephosphorylate key players of activating receptor signaling pathways. We hypothesized that SHP-2 deletion would have major effects on T cell development by altering the thresholds for activation, as well as positive and negative selection. Surprisingly, using mice conditionally deficient for SHP-2 in the T cell lineage, we show that the development of these lymphocytes is globally intact. In addition, our data demonstrate that SHP-2 absence does not compromise T cell effector functions, suggesting that SHP-2 is dispensable in these cells. Unexpectedly, in aging mice, Ptpn11 gene deletion driven by CD4 Cre recombinase leads to cartilage tumors in wrist bones in a T cell-independent manner. These tumors resemble miniature cartilaginous growth plates and contain CD4-lineage positive chondrocyte-like cells. Altogether these results indicate that SHP-2 is a cartilage tumor suppressor during aging.

Invariant natural killer T (iNKT) cells are cytotoxic T cells that respond to glycolipid antigens presented by CD1d. Therapeutic activation of iNKT cells with α-galactosylceramide (α-GalCer) can prevent and reverse tumor growth in mice and clinical trials involving α-GalCer-stimulated iNKT cells are ongoing in humans. B cells express CD1d, however, we show that CD1d expression is reduced on B cells from patients with chronic lymphocytic leukemia (CLL). B cells from CLL patients pulsed with α-GalCer failed to stimulate cytolytic degranulation by iNKT cell lines, but could present the more potent glycolipid analogue, 7DW8-5. Retinoic acid receptor-α (RAR-α) agonists induced CD1d expression by CLL B cells, restoring their ability to present α-GalCer to CD8α + iNKT cells, resulting in cytolytic degranulation. Thus, RAR-α agonists can augment the anti-tumor activities of iNKT cells against CLL cells in vitro. Their inclusion in iNKT cell-based therapies may benefit patients with CLL., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Chronic inflammation of genital tract is thought to play a major role in male fertility disorder. Natural killer (NK) T cells are a heterogeneous group of T cells that share properties of both T cells and NK cells which display immunoregulatory properties. However, little is known regarding the presence and function of NK T cells in ejaculates from patients with chronic inflammation of genital tract. Invariant NK T (iNK T) cells were detected by invariant (Vα24-JαQ) TCR chain in ejaculates from patients suffering from chronic inflammation of genital tract (CIGT) using flow cytometry and immunofluorescence of double staining (n=40). Inflammatory cytokines interleukin (IL)-6, IL-17, and IFN-γ were detected in cell-free seminal plasma using an enzyme-linked immunosorbent assay (ELISA). The correlation between the percentage of iNK T cells and spermatozoa count, motility, vitality, seminal IL-6, IL-17, and IFN-γ was investigated. Significant percentages of iNK T cells above 10% were detected in 50% (CIGT-NKT + group). A negative correlation was detected between the percentage of iNK T cells and spermatozoa count (r=-.5957, P=.0056), motility (r=-.6163, P=.0038), and vitality (r=-.8032, P=.0019) in CIGT-NKT + group (n=20). Interestingly, a significant correlation of iNK T cells to seminal IL-6 (r=.7083, P=.0005), IFN-γ (r=.9578, P<.0001) was detected whereas lack of correlation between iNK T cells and IL-17 (r=-.1557, P=.5122) in CIGT-NKT + group. The proliferative response of iNK T cells could accompany an inflammatory response to spermatozoa and consequently influence sperm quality through secretion of IFN-γ but not IL-17 under chronic inflammatory condition., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The ability of a rigid α-Tn mimetic (compound 1) to activate murine invariant natural killer T (iNKT) and human natural killer (NK) cells, two subsets of lymphocytes involved in cancer immunesurveillance, was investigated. For this purpose, the mimetic 1 was properly conjugated to a stearic acid containing glycerol-based phospholipid (compound 5) to be presented, in the context of the conserved non polymorphic major histocompatibility complex class I-like molecules (CD1d), to iNKT cells. On the contrary, the mimetic 1 was conjugated to a multivalent peptide-based scaffold (compound 6) to induce NK cell activation.

Invariant natural killer T (iNKT) cells serve as a bridge between innate and adaptive immunity and have been shown to play an important role in immune regulation, defense against pathogens, and cancer immunity. Recent data also suggest that this compartment of the immune system plays a significant role in reducing graft-versus-host disease (GVHD) in the setting of allogeneic hematopoietic stem cell transplantation. Murine studies have shown that boosting iNKT numbers through certain conditioning regimens or adoptive transfer leads to suppression of acute or chronic GVHD. Preclinical work reveals that iNKT cells exert their suppressive function by expanding regulatory T cells in vivo , though the exact mechanism by which this occurs has yet to be fully elucidated. Human studies have demonstrated that a higher number of iNKT cells in the graft or in the peripheral blood of the recipient post-transplantation are associated with a reduction in GVHD risk, importantly without a loss of graft-versus-tumor effect. In two separate analyses of many immune cell subsets in allogeneic grafts, iNKT cell dose was the only parameter associated with a significant improvement in GVHD or in GVHD-free progression-free survival. Failure to reconstitute iNKT cells following allogeneic transplantation has also been associated with an increased risk of relapse. These data demonstrate that iNKT cells hold promise for future clinical application in the prevention of GVHD in allogeneic stem cell transplantation and warrant further study of the immunoregulatory functions of iNKT cells in this setting.

Cardiovascular disease (CVD), comprising coronary heart disease and stroke, is one of the most important causes of death in patients with systemic lupus erythematosus (SLE). The risks of developing both clinical CVD and sub-clinical atherosclerosis are increased in patients with SLE. This increase is not fully explained by traditional cardiovascular risk factors such as smoking, hypertension and elevated cholesterol, and it is believed that immune dysfunction also contributes to CVD risk in SLE. In particular, recent studies have shown that abnormalities in both serum lipid profile and the autoantibody and T lymphocyte response to lipids may play a role in development of atherosclerosis. The standard CVD risk calculation algorithms based on traditional risk factors underestimate the risk of developing CVD in patients with SLE. Thus, novel algorithms incorporating new biomarkers such as pro-inflammatory high-density lipoprotein and use of imaging techniques such as carotid ultrasound scanning may become increasingly valuable., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The CD1d-restricted invariant natural killer T (iNKT) cells are implicated in innate immune responses against human immunodeficiency virus (HIV). However, the determinants of cellular dysfunction across the iNKT cells subsets are seldom defined in HIV disease. Herein, we provide evidence for the involvement of the negative checkpoint regulator (NCR) 2B4 in iNKT cell alteration in a well-defined cohort of HIV-seropositive anti-retroviral therapy (ART) naïve, ART-treated, and elite controllers (ECs). We report on exaggerated 2B4 expression on iNKT cells of HIV-infected treatment-naïve individuals. In sharp contrast to CD4 - iNKT cells, 2B4 expression was significantly higher on CD4 + iNKT cell subset. Notably, an increased level of 2B4 on iNKT cells was strongly correlated with parameters associated with HIV disease progression. Further, iNKT cells from ART-naïve individuals were defective in their ability to produce intracellular IFN-γ. Together, our results suggest that the levels of 2B4 expression and the downstream co-inhibitory signaling events may contribute to impaired iNKT cell responses.

During toxic shock syndrome (TSS), bacterial superantigens trigger a polyclonal T -cell response leading to a potentially catastrophic "cytokine storm". Whether innate-like invariant natural killer T (iNKT) cells, with remarkable immunomodulatory properties, participate in TSS is unclear. Using genetic and cell depletion approaches, we generated iNKT cell-deficient, superantigen-sensitive HLA-DR4-transgenic (DR4tg) mice, which were compared with their iNKT-sufficient counterparts for responsiveness to staphylococcal enterotoxin B (SEB). Both approaches indicate that iNKT cells are pathogenic in TSS. Importantly, treating DR4tg mice with a TH2-polarizing glycolipid agonist of iNKT cells reduced SEB-inflicted morbidity/mortality. Therefore, iNKT cells may constitute an attractive therapeutic target in superantigen-mediated illnesses., (© The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.)

Multiple sclerosis (MS) is a chronic progressive inflammatory demyelinating disorder of the central nervous system, and in several countries is a leading cause of permanent neurological disability in young adults, particularly women. MS is considered an autoimmune disease, caused by an aberrant immune response to environmental triggers in genetically susceptible subjects. However, the contribution of the innate or of the adaptive immune system to the development and progression of the disease has not yet been fully elucidated. Innate-like T lymphocytes are unconventional T cells that bridge the innate and adaptive arms of the immune system, because they use a T cell receptor to sense external ligands, but behave like innate cells when they rapidly respond to stimuli. These cells could play an important role in the pathogenesis of MS. Here, we focus on invariant natural killer T (iNKT) cells and mucosal-associated invariant T (MAIT) cells, and we review the current knowledge on their biology and possible involvement in MS. Although several studies have evaluated the frequency and functions of iNKT and MAIT cells both in MS patients and in experimental mouse models, contradictory observations have been reported, and it is not clear whether they exert a protective or a pro-inflammatory and harmful role. A better understanding of how immune cells are involved in MS, and of their interactions could be of great interest for the development of new therapeutic strategies., (Copyright © 2017 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.)

Background: Allergic sensitization might be influenced by the lipids present in allergens, which can be recognized by natural killer T (NKT) cells on antigen-presenting cells (APCs). The aim of this study was to analyze the effect of olive pollen lipids in human APCs, including monocytes as well as monocyte-derived macrophages (Mϕ) and dendritic cells (DCs)., Methods: Lipids were extracted from olive (Olea europaea) pollen grains. Invariant (i)NKT cells, monocytes, Mϕ, and DCs were obtained from buffy coats of healthy blood donors, and their cell phenotype was determined by flow cytometry. iNKT cytotoxicity was measured using a lactate dehydrogenase assay. Gene expression of CD1A and CD1D was performed by RT-PCR, and the production of IL-6, IL-10, IL-12, and TNF-α cytokines by monocytes, Mϕ, and DCs was measured by ELISA., Results: Our results showed that monocytes and monocyte-derived Mϕ treated with olive pollen lipids strongly activate iNKT cells. We observed several phenotypic modifications in the APCs upon exposure to pollen-derived lipids. Both Mϕ and monocytes treated with olive pollen lipids showed an increase in CD1D gene expression, whereas upregulation of cell surface CD1d protein occurred only in Mϕ. Furthermore, DCs differentiated in the presence of human serum enhance their surface CD1d expression when exposed to olive pollen lipids. Finally, olive pollen lipids were able to stimulate the production of IL-6 but downregulated the production of lipopolysaccharide- induced IL-10 by Mϕ., Conclusions: Olive pollen lipids alter the phenotype of monocytes, Mϕ, and DCs, resulting in the activation of NKT cells, which have the potential to influence allergic immune responses., (© 2017 S. Karger AG, Basel.)

Invariant natural killer T cells (iNKTs) are important innate immune cells which get involved in various immune responses in both mice and humans. These immune reactions range from self-tolerance to development of autoimmunity and responses to pathogens and tumor development. In this study, we aimed to explore the effects of the novel immunostimulators (CH1b and CH2b) containing thiazolidin-4-one on the functions of human invariant natural killer T cells (iNKTs). First of all, iNKTs in peripheral blood mononuclear cells were expanded with α-Galactosylceramide (α-Galcer) in vitro. Then, the highly purified iNKTs were isolated from PBMCs using magnetic cells sorting (MACS). Next, we investigated the impacts of CH1b and CH2b on proliferation, cytokines production, cytotoxicity, and the associated signaling pathways in iNKT cells. Finally, we found that CH2b could significantly promote the activated iNKTs proliferation, increase the production of Th2 cytokines, and induce Th0 differentiation into Th2 subset via GATA 3 signaling pathway. Besides, CH2b could markedly enhance the cytotoxic ability of the activated iNKTs. Therefore, we concluded that CH2b, a promising candidate immunostimulator, might be used for the treatment of infections, tumors, autoimmune and allergic diseases, and for the correction of Th1/Th2 balance disorders in future., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The expression of N-glycolyl-monosialodihexosyl-ganglioside (NGcGM3) in humans is restricted to cancer cells; therefore, it is a tumor antigen. There are measurable quantities of circulating anti-NGcGM3 antibodies (aNGcGM3 Abs) in human serum. Interestingly, some people have circulating Ag-specific immunoglobulins G (IgGs) that are capable of complement mediated cytotoxicity against NGcGM3 positive cells, which is relevant for tumor surveillance. In light of the chemical nature of Ag, we postulated it as a candidate ligand for CD1d. Furthermore, we hypothesize that the immune mechanism involved in the generation of these Abs entails cross talk between B lymphocytes (Bc) and invariant natural killer T cells (iNKT). Combining cellular techniques, such as flow cytometry and biochemical assays, we demonstrated that CD1d binds to NGcGM3 and that human Bc present NGcGM3 in a CD1d context according to two alternative strategies. We also showed that paraformaldehyde treatment of cells expressing CD1d affects the presentation. Finally, by co-culturing primary human Bc with iNKT and measuring Ki-67 expression, we detected a reproducible increment in the proliferation of the iNKT population when Ag was on the medium. Our findings identify a novel, endogenous, human CD1d ligand, which is sufficiently competent to stimulate iNKT. We postulate that CD1d-restricted Bc presentation of NGcGM3 drives effective iNKT activation, an immunological mechanism that has not been previously described for humans, which may contribute to understanding aNGcGM3 occurrence.

Rationale: Ischemia-reperfusion (IR) injury after lung transplantation, which affects both short- and long-term allograft survival, involves activation of NADPH oxidase 2 (NOX2) and activation of invariant natural killer T (iNKT) cells to produce IL-17. Adenosine A2A receptor (A2AR) agonists are known to potently attenuate lung IR injury and IL-17 production. However, mechanisms for iNKT cell activation after IR and A2AR agonist-mediated protection remain unclear., Objectives: We tested the hypothesis that NOX2 mediates IL-17 production by iNKT cells after IR and that A2AR agonism prevents IR injury by blocking NOX2 activation in iNKT cells., Methods: An in vivo murine hilar ligation model of IR injury was used, in which left lungs underwent 1 hour of ischemia and 2 hours of reperfusion., Measurements and Main Results: Adoptive transfer of iNKT cells from p47(phox-/-) or NOX2(-/-) mice to Jα18(-/-) (iNKT cell-deficient) mice significantly attenuated lung IR injury and IL-17 production. Treatment with an A2AR agonist attenuated IR injury and IL-17 production in wild-type (WT) mice and in Jα18(-/-) mice reconstituted with WT, but not A2AR(-/-), iNKT cells. Furthermore, the A2AR agonist prevented IL-17 production by murine and human iNKT cells after acute hypoxia-reoxygenation by blocking p47(phox) phosphorylation, a critical step for NOX2 activation., Conclusions: NOX2 plays a key role in inducing iNKT cell-mediated IL-17 production and subsequent lung injury after IR. A primary mechanism for A2AR agonist-mediated protection entails inhibition of NOX2 in iNKT cells. Therefore, agonism of A2ARs on iNKT cells may be a novel therapeutic strategy to prevent primary graft dysfunction after lung transplantation.

Purpose: Invariant Natural Killer T cells (iNKT) are a specialized subset of T cells that use their T cell receptor to recognize self and foreign lipids presented by CD1d as cognate antigens. iNKT have been shown to have either protective or harmful roles in many pathological states, including microbial infection, autoimmune disease, allergic disease and cancer. Accumulating evidence seems to suggest that this unique T cell subset combines both classically innate and adaptive immunologic characteristic. Considering these recent data, the aim of work was to review the current knowledge about iNKT in eutopic and ectopic endometrium., Methods: Narrative overview, synthesizing the findings of literature retrieved from searches of computerized databases., Results: Currently, the immune paradigm of reproduction is gradually changing shape: recent data confirmed that cytokine milieu influences the development and plasticity of different subtype of mononuclear cells, and in turn it can be influenced by the cytokine production of the latter. Among the different NKT cell populations, the recently characterized iNKT seems to share actions typical both of innate and adaptive immunity, being capable of secreting Th1 as well as Th2 cytokine pattern. Moreover, several subtypes of iNKT were identified, who partially express the same master transcription factors of the corresponding T cells counterpart., Conclusions: Although the data about iNKT's actions in eutopic and ectopic endometrium are still scarce, it is possible to hypothesize that future investigation can shed light on this point, thus allowing a better knowledge about the regulation of these two microenvironments.

Aim: To investigate the prognostic role of invariant natural killer T (iNKT) cells and antibody-dependent cell-mediated cytotoxicity (ADCC) in wild type KRAS metastatic colorectal cancer (mCRC) patients treated with cetuximab., Methods: Forty-one KRAS wt mCRC patients, treated with cetuximab and irinotecan-based chemotherapy in II and III lines were analyzed. Genotyping of single nucleotide polymorphism (SNP)s in the FCGR2A, FCGR3A and in the 3' untranslated regions of KRAS and mutational analysis for KRAS, BRAF and NRAS genes was determined either by sequencing or allelic discrimination assays. Enriched NK cells were obtained from lymphoprep-peripheral blood mononuclear cell and iNKT cells were defined by co-expression of CD3, TCRVα24, TCRVβ11. ADCC was evaluated as ex vivo NK-dependent activity, measuring lactate dehydrogenase release., Results: At basal, mCRC patients performing ADCC activity above the median level (71%) showed an improved overall survival (OS) compared to patients with ADCC below (median 16 vs 8 mo; P = 0.026). We did not find any significant correlation of iNKT cells with OS (P = 0.19), albeit we observed a trend to a longer survival after 10 mo in patients with iNKT above median basal level (0.382 cells/microliter). Correlation of OS and progression-free survival (PFS) with interesting SNPs involved in ADCC ability revealed not to be significant. Patients carrying alleles both with A in FCGR2A and TT in FCGR3A presented a trend of longer PFS (median 9 vs 5 mo; P = 0.064). Chemotherapy impacted both iNKT cells and ADCC activity. Their prognostic values get lost when we analysed them after 2 and 4 mo of treatment., Conclusion: Our results suggest a link between iNKT cells, basal ADCC activity, genotypes in FCGR2A and FCGR3A, and efficacy of cetuximab in KRAS wt mCRC patients.

Gaucher Disease (GD) is a rare autosomal recessive disorder caused by the deficient activity of beta-glucocerebrosidase. GD is one of the lysosomal storage diseases with the most remarkable alterations in the immune system, and that may manifest clinically as autoimmune disorders and malignancy. We reported the immunological evaluation of a patient with GD and lupus nephritis. Decreased absolute values of T, and NK, and an inversion of CD4(+)/CD8(+) ratio, low levels of IgM and normal B cells were found when compared to reference values in a Brazilian population. Absence ofCD4(+)CD25(high)Foxp3(+) Treg and high levels of total NKT, iNKT cells and CD8(+) iNKT subsets were also observed when compared to the healthy control and GD patient without lupus nephritis. Treg subset and CD8(+) iNKT abnormalities might be involved in severe lupus nephritis in a GD patient. We conclude by emphasizing the importance of the immunological evaluation on early diagnosis of autoimmunity contributing to reduce mortality and morbidity of these patients., (Copyright © 2015 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.)

We describe a protective early acquired immune response to pneumococcal pneumonia that is mediated by a subset of B1a cells. Mice deficient in B1 cells (xid), or activation-induced cytidine deaminase (AID(-/-) ), or invariant natural killer T (iNKT) cells (Jα18(-/-) ), or interleukin-13 (IL-13(-/-) ) had impaired early clearance of pneumococci in the lung, compared with wild-type mice. In contrast, AID(-/-) mice adoptively transferred with AID(+/+) B1a cells, significantly cleared bacteria from the lungs as early as 3 days post infection. We show that this early bacterial clearance corresponds to an allergic contact sensitivity-like cutaneous response, probably due to a subpopulation of initiating B1a cells. In the pneumonia model, these B1a cells were found to secrete higher affinity antigen-specific IgM. In addition, as in contact sensitivity, iNKT cells were required for the anti-pneumococcal B1a cell initiating response, probably through early production of IL-13, given that IL-13(-/-) mice also failed to clear infection. Our study is the first to demonstrate the importance of AID in generating an appropriate B1a cell response to pathogenic bacteria. Given the antibody affinity and pneumonia resistance data, natural IgM produced by conventional B1a cells are not responsible for pneumonia clearance compared with the AID-dependent subset., (© 2015 John Wiley & Sons Ltd.)

Background: Invariant natural killer T (iNKT) cells recognize lipids presented by CD1d and have been implicated in the pathogenesis of allergic asthma. Recognition of plant pollen lipids by iNKT cells and their role in allergic responses are poorly defined. Objective: Our goal was to investigate whether iNKT cells can be activated by monocyte-derived dendritic cells (DCs) exposed to lipid antigens from Olea europaea. Methods: DCs generated in vitro were exposed to O europaea pollen grains or lipids isolated from them. Expression of lipid-presenting molecules (CD1), as well as maturation markers (HLA-DR, HLA-I, CD86, and CD80 molecules), on DCs was analyzed. iNKT cell activation after coculture with DCs was evaluated based on expansion, cytokine production, and cytotoxicity tests. Results: DCs upregulated CD1d and CD86 expression and downregulated CD1a expression after exposure to a whole extract of olive pollen lipids. CD1d and CD1a were regulated at the transcriptional level in a peroxisome proliferator-activated receptor γ activation–dependent manner. Polar lipids, diacylglycerols, free fatty acids, and triacylglycerols isolated from pollen grains upregulate CD1d. The increase in CD1d expression on the DC cell surface induced by polar lipids was not regulated at the RNA level. iNKT cells efficiently recognize DCs treated with the different lipids isolated from olive pollen grains. Conclusions: Lipids from O europaea pollen upregulate CD1d and CD86 molecules on DCs, which are then able to activate iNKT cells through a CD1d-dependent pathway. [ABSTRACT FROM AUTHOR]

Background: Immune tolerance is maintained in the liver, and perturbation of tolerance can lead to immune-mediated liver diseases such as autoimmune hepatitis (AIH). Invariant natural killer T (iNKT) cells and γδT cells have been shown to maintain immune homeostasis as regulatory cells and to play pathogenic roles in immune-mediated diseases as effector cells. We hypothesized that iNKT cells and γδT cells are involved in the maintenance of hepatic immune tolerance and immune-mediated liver disease., Methods: We measured liver inflammation and the cytokine profiles of liver mononuclear cells in BALB/c wild-type (WT) mice and BALB/c Jα18-deficient (KO) mice lacking iNKT cells. We also examined the role of γδT cells in AIH using liver tissue from AIH patients and control subjects., Results: Spontaneous liver inflammation, hepatocyte damage, and anti-nuclear-antibody production occurred in Jα18 KO mice but not in WT mice. Furthermore, liver mononuclear cells from Jα18 KO mice, but not those from WT mice, produced interleukin-17 (IL-17). γδT cells were the primary producers of the cytokine, and they were more abundant in the livers of Jα18 KO mice than in those of WT mice. In Jα18 KO mice, the administration of anti-γδT-cell-receptor antibody abolished liver inflammation, hepatocyte damage, and IL-17 production. γδT cells accumulated in the livers of AIH patients but not in those of the control subjects., Conclusions: Our results suggest a protective role for iNKT cells, a pathologic role for γδT cells, and an association between these cells in the pathogenesis of AIH.

The lipid antigen α-galactosylceramide (α-GalCer) is a potent activator of invariant natural killer T-cells (iNKT cells) and can stimulate cytotoxic and anti-tumour immune responses. However optimal responses appear to be induced by α-GalCer when cell-based vaccines are delivered intravenously. Here we investigated if co-delivery of protein and peptide antigens along with α-GalCer in a liposomal formulation could stimulate therapeutic anti-tumour immune responses. Cationic liposomes were inherently immune-stimulatory and induced cytotoxic immune responses when delivered both by intravenous and subcutaneous injection. However, only vaccine delivered intravenously stimulated therapeutic anti-tumour immune responses to a peptide antigen. Surface modification with polyethylene glycol (PEG) did not improve immune responses to either intravenously or subcutaneously delivered vaccines. Immune responses to short and long peptide sequences (CD8 and CD4 epitopes) of the self-antigen tyrosinase-related protein 2 (TRP2) as a vaccine antigen, co-delivered with α-GalCer in either cationic liposomes or PBS were further examined. Enhanced production of IFN-γ, increased cytotoxic T-cell responses and tumour survival were observed when a long TRP2-peptide was delivered with α-GalCer in cationic liposomes., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Study Objectives: Emerging evidence links obstructive sleep apnea (OSA) with increased cancer incidence and mortality. Invariant natural killer T (iNKT) cells play an important role in cancer immunity. We hypothesized that patients with OSA have low number of circulating invariant natural killer T (iNKT) cells, which may also be functionally impaired. This study aims to evaluate the frequency of circulating iNKT cells in OSA., Design: We evaluated the frequency of circulating iNKT cells by flow cytometry in 33 snorers being assessed for possible OSA. Using iNKT cell lines, we also evaluated the effect of exposure to hypoxia over 24 hours on apoptosis, cytotoxicity, and cytokine production., Setting: Teaching hospital based sleep unit and research laboratory., Patients: Thirty-three snorers were evaluated: 9 with no OSA (apnea-hypopnea frequency [AHI] < 5/h), 12 with mild-moderate OSA (AHI 5-30) and 12 with severe OSA (AHI > 30)., Measurements and Results: Patients with severe OSA had considerably fewer iNKT cells (0.18%) compared to patients with mild-moderate (0.24%) or no OSA (0.35%), P = 0.0026. The frequency of iNKT cells correlated negatively with apnea-hypopnea index (r = -0.58, P = 0.001), oxygen desaturation index (r = -0.58, P = 0.0003), and SpO2% < 90% (r = -0.5407, P = 0.005). The frequency of iNKT cells increased following 12 months of nCPAP therapy (P = 0.015). Hypoxia resulted in increased apoptosis (P = 0.016) and impaired cytotoxicity (P = 0.035)., Conclusion: Patients with obstructive sleep apnea (OSA) have significantly reduced levels of circulating invariant natural killer T (iNKT) cells and hypoxia leads to impaired iNKT cell function. These observations may partly explain the increased cancer risk reported in patients with OSA., (© 2015 Associated Professional Sleep Societies, LLC.)

Type 1 diabetes (T1D) is an autoimmune disease that is characterized by the specific destruction of insulin-producing pancreatic β cells. Invariant natural killer T (iNKT) cells have been associated with development of T1D. Class I MHC-restricted T cell-associated molecule (CRTAM) is expressed on activated iNKT, CD8(+), and CD4(+) T cells, and it is associated with the pro-inflammatory profiles of these cells. Crtam gene expression in CD3(+) lymphocytes from non-obese diabetic (NOD) mice is associated with T1D onset. However, expression of CRTAM on T cells from patients with T1D has not yet been evaluated. We compared iNKT cell (CD3(+)Vα24(+)Vβ11(+)) numbers and CRTAM expression in a Mexican population with recent-onset T1D and their first-degree relatives with control families. Remarkably, we found lower iNKT cell numbers in T1D families, and we identified two iNKT cell populations in some of the families. One iNKT cell population expressed high iTCR levels (iNKT(hi)), whereas another expressed low levels (iNKT(lo)) and also expressed CRTAM. These findings support a probable genetic determinant of iNKT cell numbers and a possible role for these cells in T1D development. This study also suggests that CRTAM identifies recently activated iNKT lymphocytes.

Background: Invariant Natural Killer T (iNKT) cells belong to innate immunity and combine T-cell receptor specificity with Natural Killer surface markers. They can produce cytokines immediately after stimulation and direct immunity to either Th1 or Th2 cytokine production. iNKT cells participate in a variety of immune responses, such as microbial infections, autoimmunity, and cancer. Type 2 Diabetes Mellitus (T2DM) has been associated with activated innate immunity and certain cytokine profile during microbial infections. This study aimed to evaluate whether iNKT cells have a role in the immune response of T2DM patients during infections with gram-negative bacteria., Method: The T2DM group consisted of patients (n =11) who had a diagnosis of T2DM for at least six months and febrile illness for three days, while the control group consisted of patients (n =11) who had not T2DM, but were febrile for three days. All patients were infected by gram-negative bacteria. Physical examination was performed, and peripheral blood was drawn on days three and six of febrile illness. Flow cytometry was utilized for iNKT cell identification with monoclonal antibodies Phycoerythrin (PE) - Cyanin (CY) 5 anti-Human CD3, Fluorescein isothiocyanate (FITC) anti-Human CD4, PE anti-human invariant NKT T-Cell Receptor. For intracellular staining, we used Alexa Fluor anti-Human interferon-γ (IFN-γ) and Allophycocyanin (APC) anti-human interleukin-4 (IL-4). The variables processed were: CD3+IL-4+iNKT+ , CD4+IL-4+iNKT+, CD3+IFNγ+iNKT+, CD4+IFNγ+iΝΚΤ+, CD3+iNKT+, CD4+iNKT+ ,CD3+IL4+, CD4+IL-4+, CD3+IFNγ+, CD4+IFNγ+ on days three and six of febrile illness (CD3+, CD4+: T lymphocyte surface markers, iNKT+: invariant Natural Killer T- Cell Receptor, IL4+: interleukin 4, IFNγ+: interferon γ)., Results: Comparisons between T2DM patients and controls revealed no statistically significant difference in any of the study's variable. Regarding within T2DM patients comparisons CD4+IL4+iNKT+, CD3+IL4+iNKT+, CD4+IFN+iNKT+, CD3+IFN+iNKT+, and CD3+iNKT+  decreased, whereas CD3+IL4+ was increased at day six compared to day three. Within control group CD4+IL4+iNKT+, CD3+IL4+iNKT+, and CD3+iNKT+ were decreased, whereas CD4+IFN+, CD3+IFN+ were increased at day six compared to day three., Conclusion: The absence of statistical difference between T2DM patients and controls implies that the role of iNKT cells is virtually the same in both groups of patients during the course of gram-negative infections and that there is no numerical variance of this cell population between the two groups. Despite the small sample size, we notice that all iNKT parameters (both IL4/IFNγ) are suppressed in the T2DM group during the later phase, but only those concerning IL4+iNKT+ in the control group, suggesting that IFNγ production remains elevated in the controls. A compensatory anti-inflammatory type-response could provide an explanation for the prevalence of IL4 production during the later phase of infection in T2DM and the sustained production of IFNγ in controls. Hippokratia 2015; 19 (3): 231-234.

Invariant natural killer T (iNKT) cells become activated during a wide variety of infections. This includes organisms lacking cognate CD1d-binding glycolipid antigens recognized by the semi-invariant T cell receptor of iNKT cells. Additional studies have shown that iNKT cells also become activated in vivo in response to microbial products such as bacterial lipopolysaccharide, a potent inducer of cytokine production in antigen-presenting cells (APCs). Other studies have shown that iNKT cells are highly responsive to stimulation by cytokines such as interleukin-12. These findings have led to the concept that microbial pathogens can activate iNKT cells either directly via glycolipids or indirectly by inducing cytokine production in APCs. iNKT cells activated in this manner produce multiple cytokines that can influence the outcome of infection, usually in favor of the host, although potent iNKT cell activation may contribute to an uncontrolled cytokine storm and sepsis. One aspect of the response of iNKT cells to microbial pathogens is that it is short-lived and followed by an extended time period of unresponsiveness to reactivation. This refractory period may represent a means to avoid chronic activation and cytokine production by iNKT cells, thus protecting the host against some of the negative effects of iNKT cell activation, but potentially putting the host at risk for secondary infections. These effects of microbial pathogens and their products on iNKT cells are not only important for understanding the role of these cells in immune responses against infections but also for the development of iNKT cell-based therapies.

Invariant natural killer T (iNKT) cells comprise a small population of αβ T lymphocytes. They bridge the innate and adaptive immune systems and mediate strong and rapid responses to many diseases, including cancer, infections, allergies, and autoimmunity. However, the study of iNKT cell biology and the therapeutic applications of these cells are greatly limited by their small numbers in vivo (∼0.01-1% in mouse and human blood). Here, we report a new method to generate large numbers of iNKT cells in mice through T-cell receptor (TCR) gene engineering of hematopoietic stem cells (HSCs). We showed that iNKT TCR-engineered HSCs could generate a clonal population of iNKT cells. These HSC-engineered iNKT cells displayed the typical iNKT cell phenotype and functionality. They followed a two-stage developmental path, first in thymus and then in the periphery, resembling that of endogenous iNKT cells. When tested in a mouse melanoma lung metastasis model, the HSC-engineered iNKT cells effectively protected mice from tumor metastasis. This method provides a powerful and high-throughput tool to investigate the in vivo development and functionality of clonal iNKT cells in mice. More importantly, this method takes advantage of the self-renewal and longevity of HSCs to generate a long-term supply of engineered iNKT cells, thus opening up a new avenue for iNKT cell-based immunotherapy.

Background: A key immunologic feature of food allergy (FA) is the presence of a T h 2-type cytokine bias. Ligation of the invariant natural killer T cell (iNKT) T-cell receptor (TCR) by sphingolipids presented via the CD1d molecule leads to copious secretion of T h 2-type cytokines. Major food allergens (eg, milk, egg) are the richest dietary source of sphingolipids (food-derived sphingolipids [food-SLs]). Nonetheless, the role of iNKTs in FA is unknown. Objective: To investigate the role of iNKTs in FA and to assess whether food-SL–CD1d complexes can engage the iNKT-TCR and induce iNKT functions. Methods: PBMCs from 15 children with cow’s milk allergy (MA), 12 children tolerant to cow’s milk but with allergy to egg, and 13 healthy controls were incubated with α-galactosylceramide (αGal), cow’s milk–sphingomyelin, or hen’s egg–ceramide. iNKTs were quantified, and their cytokine production and proliferation were assessed. Human CD1d tetramers loaded with milk-sphingomyelin or egg-ceramide were used to determine food-SL binding to the iNKT-TCR. Results: Milk-sphingomyelin, but not egg-ceramide, can engage the iNKT-TCR and induce iNKT proliferation and T h 2-type cytokine secretion. Children with FA, especially those with MA, had significantly fewer peripheral blood iNKTs and their iNKTs exhibited a greater T h 2 response to αGal and milk-sphingomyelin than iNKTs of healthy controls. Conclusion: iNKTs from children with FA, especially those with MA, are reduced in number and exhibit a T h 2 bias in response to αGal and milk-sphingomyelin. These data suggest a potential role for iNKTs in FA. [ABSTRACT FROM AUTHOR]

Background: Although invariant natural killer T (iNKT) cells have been shown to play a critical role in the pathogenesis of asthma, the role of iNKT cells in atopic dermatitis (AD) has not been well evaluated. Objective: We investigated whether iNKT cells in patients with AD increased and whether iNKT cells were activated by thymic stromal lymphopoietin (TSLP), which is highly expressed in keratinocytes of AD. Methods: We assessed the population of iNKT cells in PBMCs of patients with AD and healthy controls (HCs) using flow cytometry. Immunohistochemistry was used to evaluate iNKT cells and TSLP expression in AD and HC skin. We also evaluated whether iNKT cells expressed the TSLP receptor, the effects of TSLP on iNKT cells, and iNKT cell–dendritic cell interactions in a TSLP-rich environment. Results: There were more iNKT cells among PBMCs of patients with moderate to severe AD than mild AD (P < .05) and HC (P < .001). The number of iNKT cells was significantly larger in severe AD skin lesions than in mild (P < .001) or moderate AD skin lesions (P < .05). TSLP expression increased in lesional skin (P < .001) but not in the sera of patients with AD (P = .729) compared with HC. iNKT cells expressed TSLP receptor protein and mRNA. TSLP directly activated iNKT cells to secrete IL-4 and IL-13, and the concurrent addition of dendritic cells further activated IFN-γ expression. Conclusion: Increased iNKT cells activated by TSLP, especially in patients with severe AD, might play an essential role in the innate allergic immune response in AD. [ABSTRACT FROM AUTHOR]

Eosinophilic esophagitis (EoE) is a recently recognized allergic disorder, characterized by eosophageal dysfunction, accumulation of ≥15 eosinophils/high-powered field, eosinophil microabssess, basal cell hyperplasia, extracellular eosinophilic granules in the esophageal epithelial mucosal biopsy and a lack of response to a 8-week proton pump inhibitor treatment. Despite the increased incidences and considerable progress made in understanding EoE pathogenesis, there are limited diagnostic and therapeutic options available for EoE. Currently, the only criterion for diagnosing EoE is repetitive esophageal endoscopic biopsies and histopathological evaluation. Antigen elimination or corticosteroid therapies are effective therapies for EoE but are expensive and have limitations, if continued in the long term. Hence, there is a great necessity for novel noninvasive diagnostic biomarkers that can easily diagnose EoE and assess effectiveness of therapy. Herein, we have provided an update on key molecules involved in the disease initiation, and progression and proposed novel noninvasive diagnostic molecules and strategies for EoE therapy.

Although invariant natural killer T (iNKT) cells influence antitumor responses indirectly by secreting cytokines and promoting the cytolytic functions of T and NK cells, we find that iNKT cells mediate direct tumoricidal activity in vitro and significantly inhibit tumor growth in vivo , even in the absence of other cytotoxic lymphocytes.

Recent studies strongly suggest an increasing role for immune responses against self-antigens (Ags) which are not encoded by the major histocompatibility complex in the immunopathogenesis of allograft rejection. Although, improved surgical techniques coupled with improved methods to detect and avoid sensitization against donor human leukocyte antigen (HLA) have improved the immediate and short term function of transplanted organs. However, acute and chronic rejection still remains a vexing problem for the long term function of the transplanted organ. Immediately following organ transplantation, several factors both immune and non immune mechanisms lead to the development of local inflammatory milieu which sets the stage for allograft rejection. Traditionally, development of antibodies (Abs) against mismatched donor HLA have been implicated in the development of Ab mediated rejection. However, recent studies from our laboratory and others have demonstrated that development of humoral and cellular immune responses against non-HLA self-Ags may contribute in the pathogenesis of allograft rejection. There are reports demonstrating that immune responses to self-Ags especially Abs to the self-Ags as well as cellular immune responses especially through IL17 has significant pro-fibrotic properties leading to chronic allograft failure. This review summarizes recent studies demonstrating the role for immune responses to self-Ags in allograft immunity leading to rejection as well as present recent evidence suggesting there is interplay between allo- and autoimmunity leading to allograft dysfunction., (Copyright © 2013 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.)

Ceramide, cholesterol, and phosphatidic acid are major basic structures for cell membrane lipids. These lipids are modified with glucose to generate glucosylceramide (GlcCer), cholesterylglucoside (ChlGlc), and phosphatidylglucoside (PtdGlc), respectively. Glucosylation dramatically changes the functional properties of lipids. For instance, ceramide acts as a strong tumor suppressor that causes apoptosis and cell cycle arrest, while GlcCer has an opposite effect, downregulating ceramide activities. All glucosylated lipids are enriched in lipid rafts or microdomains and play fundamental roles in a variety of cellular processes. In this review, we discuss the biological functions and metabolism of these three glucosylated lipids., (Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.)