Regulatory natural killer T cells protect against spontaneous and recurrent type 1 diabetes

Natural killer T cells and other innate-like T lymphocytes as emerging platforms for allogeneic cancer cell therapy

T cells expressing chimeric antigen receptors (CARs) have achieved major clinical success in patients with hematologic malignancies. However, these treatments remain largely ineffective for solid cancers and require significant time and resources to be manufactured in an autologous setting. Developing alternative immune effector cells as cancer immunotherapy agents that can be employed in allogeneic settings is crucial for the advancement of cell therapy. Unlike T cells, Vα24-invariant natural killer T cells (NKTs) are not alloreactive and can therefore be generated from allogeneic donors for rapid infusion into numerous patients without the risk of graft-versus-host disease. Additionally, NKT cells demonstrate inherent advantages over T-cell products, including the ability to traffic to tumor tissues, target tumor-associated macrophages, transactivate NK cells, and cross-prime tumor-specific CD8 T cells. Both unmodified NKTs, which specifically recognize CD1d-bound glycolipid antigens expressed by certain types of tumors, and CAR-redirected NKTs are being developed as the next generation of allogeneic cell therapy products. In this review, we describe studies on the biology of NKTs and other types of innate-like T cells and summarize the clinical experiences of unmodified and CAR-redirected NKTs, including recent interim reports on allogeneic NKTs.

Combination therapy with anti-CD20 mAb and IL-10 gene to reverse type 1 diabetes by attenuating pancreatitis and inhibiting apoptosis in NOD mice

AIMS

To assess the combination therapy of anti-CD20 mabs and adenovirus-mediated interleukin-10 (IL-10) gene delivery on the prevention of type 1 diabetes (T1D) in non-obese diabetes (NOD) mice.

MAIN METHODS

In present study, we simultaneously blocked the B cell interactions and recovered the Th cell subset proportion by using through anti-CD20 Mab and adenovirus-mediated gene delivery of IL-10, respectively. After 9 consecutive days of combination therapy, various measurements, including hematoxylin-eosin staining (HE), terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling assay (TUNEL), immunohistochemistry, ELISA, PCR and western blot were applied to further assess the efficacy.

KEY FINDINGS

The results suggested that the combination intervention reduced the T1D-associated morbidity of NOD mice, promote insulin secretion, control blood glucose and ease pancreatitis. Moreover, the combination therapy might play a protective role in pancreatic β cells by suppressing the expression of TNF-α and Fas, blocking the Caspase-8 and Caspase-3 apoptotic pathways and activating the Bcl-2 anti-apoptotic pathway. Finally, the combination intervention may up-regulate the gene expression of CK-19 and PDX-1 and further accelerate the differentiation and proliferation of pancreatic β cells.

SIGNIFICANCE

Therefore, the combination intervention with anti-CD20 mabs and the IL-10 gene plays a role in the prevention of T1D to some extent in NOD mice.

Advances in the cellular immunological pathogenesis of type 1 diabetes

Type 1 diabetes is an autoimmune disease caused by the immune-mediated destruction of insulin-producing pancreatic β cells. In recent years, the incidence of type 1 diabetes continues to increase. It is supposed that genetic, environmental and immune factors participate in the damage of pancreatic β cells. Both the immune regulation and the immune response are involved in the pathogenesis of type 1 diabetes, in which cellular immunity plays a significant role. For the infiltration of CD4(+) and CD8(+) T lymphocyte, B lymphocytes, natural killer cells, dendritic cells and other immune cells take part in the damage of pancreatic β cells, which ultimately lead to type 1 diabetes. This review outlines the cellular immunological mechanism of type 1 diabetes, with a particular emphasis to T lymphocyte and natural killer cells, and provides the effective immune therapy in T1D, which is approached at three stages. However, future studies will be directed at searching for an effective, safe and long-lasting strategy to enhance the regulation of a diabetogenic immune system with limited toxicity and without global immunosuppression.

MicroRNAs are key regulators controlling iNKT and regulatory T-cell development and function

MicroRNAs (miRNAs) are an abundant class of evolutionarily conserved, small, non-coding RNAs that post-transcriptionally regulate expression of their target genes. Emerging evidence indicates that miRNAs are important regulators that control the development, differentiation and function of different immune cells. Both CD4(+)CD25(+)Foxp3(+) regulatory T (Treg) cells and invariant natural killer T (iNKT) cells are critical for immune homeostasis and play a pivotal role in the maintenance of self-tolerance and immunity. Here, we review the important roles of miRNAs in the development and function of iNKT and Treg cells.

Anti-tumor potential of type-I NKT cells against CD1d-positive and CD1d-negative tumors in humans

Vα24-invariant natural killer T cells (NKTs) are strictly CD1d-restricted, and CD1d expression has been found in several types of leukemia and lymphoma as well as in brain tumors suggesting that these malignancies could be targeted for direct NKT-cell cytotoxicity. Several studies have revealed strong positive associations between the numbers of tumor-infiltrating or circulating NKTs with improved disease outcome in patients with diverse types of CD1d-negative solid tumors. The mechanism by which NKTs mediate anti-tumor activity against CD1d-negative tumors has long remained enigmatic. Recent evidence indicates that NKTs can suppress tumor growth indirectly by targeting CD1d-positive elements of tumor-supportive stroma such as tumor-associated macrophages. This review summarizes the current knowledge about the mechanisms that regulate NKT-cell localization to the tumor site and their interaction with the tumor microenvironment. The discussed strategies for pharmacologic modulation and genetic engineering of NKTs may lead to development of effective and broadly applicable immunotherapies of cancer.

IL-10/TGF-beta-treated dendritic cells, pulsed with insulin, specifically reduce the response to insulin of CD4+ effector/memory T cells from type 1 diabetic individuals

INTRODUCTION

Diabetogenic autoreactive T cells with effector/memory characteristics are described in type 1 diabetes patients (T1D). Alternatively activated dendritic cells (aaDCs) have been regarded as promising tools for clinical application in autoimmune diseases (ADs), although their ability to induce antigen-specific tolerance in T cells derived from ADs has yet to be determined.

METHODS

Monocyte-derived dendritic cells (DCs) were produced utilizing GM-CSF and IL-4, and aaDCs by adding IL-10 and TGF-beta (10/TGF-DC) during differentiation. Both cell groups were insulin-loaded, maturated with lipopolysaccharide, and cocultured with autologous effector/memory T cells derived from T1D individuals, in order to evaluate the induction of insulin-specific tolerance.

RESULTS AND DISCUSSION

In five of eight T1D patients analyzed in vitro, 10/TGF-DC were able to induce insulin-specific tolerance in effector/memory CD4+ T cells (50.4% +/- 13.2 less proliferation), without affecting the proliferative response to an unrelated antigen (candidin). Tolerance induction was dependent on the current activation state of CD4+ T cells in each patient. 10/TGF-DC-stimulated T cells acquired an IL-2(low)IFN-gamma(low)IL-10(high) cytokine profile, and their hyporesponsiveness could be reverted upon exposure to IL-2. This study shows a perspective about the in vitro ability of monocyte-derived 10/TGF-DC to induce antigen-specific tolerance in effector/memory T cells generated during the course of an autoimmune disease.

Beta-glycosphingolipids improve glucose intolerance and hepatic steatosis of the Cohen diabetic rat

A link between altered levels of various gangliosides and the development of insulin resistance was described in transgenic mice. Naturally occurring glycosphingolipids were shown to exert immunomodulatory effects in a natural killer T (NKT) cell-dependent manner. This study examined whether glycosphingolipid-induced modulation of the immune system may reduce pancreatic and liver steatosis and stimulate insulin secretion in the Cohen diabetes-sensitive (CDS) rat, a lean model of non-insulin-resistant, nutritionally induced diabetes. Four groups of CDS rats fed a diabetogenic diet were treated with daily intraperitoneal injections of glycosphingolipids beta-glucosylceramide, beta-lactosylceramide, a combination of both (IGL), or vehicle (PBS) for up to 45 days. Immune modulation was assessed by fluorescence-activated cell sorting analysis of intrahepatic and intrasplenic lymphocytes. Steatosis was assessed by MRI imaging and histological examination of liver and pancreas, Blood glucose and plasma insulin concentrations were assessed during an oral glucose tolerance test. Administration of glycosphingolipids, particularly IGL, increased intrahepatic trapping of CD8 T and NKT lymphocytes. Pancreatic and liver histology were markedly improved and steatosis was reduced in all treated groups compared with vehicle-treated rats. Insulin secretion was restored after glycosphingolipid treatment, resulting in improved glucose tolerance. The immunomodulatory effect of beta-glycosphingolipids improved the beta-cell function of the hyperglycemic CDS rat. Thus our results suggest a role for the immune system in the pathogenesis of diabetes in this model.

CXCL10 blockade protects mice from cyclophosphamide-induced cystitis

Background

Alterations in serum CXCR3 ligand levels were examined in interstitial cystitis (IC) patients; similar expression patterns in serum as well as CXCR3, CXCR3 ligands, and cytokines expressed by peripheral and local leukocyte subpopulations were characterized during cyclophosphamide (CYP)-induced acute cystitis in mice.

Results

Serum levels of monokine-induced by interferon-γ (IFN-γ) (MIG/CXCL9), IFN-γ-inducible protein-10 (IP-10/CXCL10), and IFN-γ-inducible T cell α chemoattractant (I-TAC/CXCL11) were elevated in patients with IC. These clinical features closely correlated with CYP-induced cystitis in mice. Serum levels of these CXCR3 ligands and local T helper type 1 (Th1) cytokines were also increased. We demonstrate that CXCR3 as well as CXCL9, CXCL10 and CXCL11 mRNA were significantly expressed by urinary bladder lymphocytes, while CXCR3 and CXCL9 transcripts were significantly expressed by iliac lymph node leukocytes following CYP treatment. We also show that the number of CD4⁺ T cells, mast cells, natural killer (NK) cells, and NKT cells were increased at systemic (spleen) and mucosal (urinary bladder and iliac lymph nodes) sites, following CYP-induced cystitis in mice. Importantly, CXCL10 blockade attenuated these increases caused by CYP.

Conclusion

Antibody (Ab)-mediated inhibition of the most abundant serum CXCR3 ligand, CXCL10, in mice decreased the local production of CXCR3 ligands as well as Th1 cytokines expressed by local leukocytes, and lowered corresponding serum levels to reduce the severity of CYP-induced cystitis. The present study is among the first to demonstrate some of the cellular and molecular mechanisms of chemokines in cystitis and may represent new drug target for this disease.

A unique T cell subset described as CD4loCD40+ T cells (TCD40) in human type 1 diabetes

Human T1D pancreatic lymph nodes contain diabetes-autoantigen responsive T cells but identification of such T cells in the periphery has proven difficult. Here we describe a unique T cell subset defined by CD4(lo) and CD40 expression (T(CD40)) that is significantly expanded in peripheral blood of T1D but not control or T2D subjects. The HLA-DR3 and DR4 alleles are considered high risk factors for T1D and T(CD40) expansion occurs in T1D subjects carrying HLA DR3 or DR4 haplotypes but, T1D subjects who do not carry either DR3 or DR4 haplotypes still have an expanded percentage of T(CD40) cells. Non-autoimmune subjects, even DR3(+) and DR4(+), do not have elevated percentages of T(CD40) cells. The majority of T(CD40) cells in T1D carry a memory phenotype and a portion of those proliferates when exposed to diabetes-associated self-antigens. A greater number of memory T(CD40) cells express CXCR3 when compared to CD40(-) memory cells and that number is significantly expanded in T1D compared to control subjects. If only total CD4(+) T cells are compared no difference in CXCR3 is seen. Furthermore, T(CD40) cells produce a Th1, pro-inflammatory cytokine profile. In healthy controls, T(CD40) cells have equally Th1 and Th2 profiles.

Alleviation of acute and chronic graft-versus-host disease in a murine model is associated with glucocerebroside-enhanced natural killer T lymphocyte plasticity

BACKGROUND

Natural killer T (NKT) lymphocytes play a role in graft-versus-host disease GVHD (GVHD). Glucocerebroside (GC) is a naturally occurring glycolipid that plays a role in the immune modulation of NKT lymphocytes. This study aims to determine the effect of GC in murine models of semiallogeneic/acute and chronic GVHD.

METHODS

Acute and chronic GVHD were generated by fusion of splenocytes from C57BL/6 to (C57BL/6xBalb/c) F1 mice, and from B10.D2 donor mice into Balb/c, respectively. Recipients were treated daily with GC. Histological and immunological parameters of GVHD were assessed.

RESULTS

Treatment with GC significantly alleviated GVHD in both models The beneficial effect of GC was associated with an increase in the intrahepatic/peripheral NKT lymphocyte ratio in the semiallogeneic/acute model. This ratio was decreased in the chronic GVHD model. A significant increase in intrahepatic CD8+ lymphocyte trapping was noted in the semiallogeneic/acute model, whereas the opposite effect was observed in the chronic GVHD model. Administration of GC led to decreased serum interferon-gamma and increased serum interleukin-4 levels in the Th1-mediated model, whereas the opposite effect was observed in the Th2-mediated models.

CONCLUSIONS

GC ameliorates GVHD in both Th1- and Th2-mediated murine models, suggesting it is able to differentially affect the immune system. GC may alleviate immunologically incongruous disorders, and may be associated with "fine tuning" of immune responses.

T cell tolerance induced by therapeutic antibodies

Ever since the discovery of Medawar, over 50 years ago, that immunological tolerance was an acquired phenomenon that could be manipulated in neonatal mice, the ability to induce therapeutic tolerance against autoantigens, allergens and organ grafts has been a major driving force in immunology. Within the last 20 years we have found that a brief treatment with monoclonal antibodies that block certain functional molecules on the surface of the T cell is able to reprogramme the established immune repertoire of the adult mouse, allowing indefinite acceptance of allografts or effective curing of autoimmune diseases. We are only now just beginning to define many of the regulatory mechanisms that induce and maintain the tolerant state with the aim of being able to safely and reliably apply these technologies to human clinical situations.

TCR Valpha14 natural killer T cells function as effector T cells in mice with collagen-induced arthritis

Natural killer (NK) T cells are a unique, recently identified cell population and are suggested to act as regulatory cells in autoimmune disorders. In the present study, designed to investigate the role of NKT cells in arthritis development, we attempted to induce arthritis by immunization of type II collagen (CIA) in Jalpha281 knock out (NKT-KO) and CD1d knock out (CD1d-KO) mice, which are depleted of NKT cells. From the results, the incidence of arthritis (40%) and the arthritis score (1.5 +/- 2.2 and 2.0 +/- 2.7) were reduced in NKT-KO and CD1d-KO mice compared to those in respective wild type mice (90%, 5.4 +/- 3.2 and 2.0 +/- 2.7, P < 0.01). Anti-CII antibody levels in the sera of NKT-KO and CD1d-KO mice were significantly decreased compared to the controls (OD values; 0.32 +/- 0.16 and 0.29 +/- 0.06 versus 0.58 +/- 0.08 and 0.38 +/- 0.08, P < 0.01). These results suggest that NKT cells play a role as effector T cells in CIA. Although the cell proliferative response and cytokine production in NKT-KO mice after the primary immunization were comparable to those in wild type mice, the ratios of both activated T or B cells were lower in NKT-KO mice than wild type mice after secondary immunization (T cells: 9.9 +/- 1.8% versus 16.0 +/- 3.4%, P < 0.01, B cells: 4.1 +/- 0.5% versus 5.1 +/- 0.7%, P < 0.05), suggesting that inv-NKT cells contribute to the pathogenicity in the development phase of arthritis. In addition, IL-4 and IL-1beta mRNA expression levels in the spleen during the arthritis development phase were lower in NKT-KO mice, while the IFN-gamma mRNA expression level was temporarily higher. These results suggest that inv-NKT cells influence cytokine production in arthritis development. In conclusion, inv-NKT cells may promote the generation of arthritis, especially during the development rather than the initiation phase.

Adoptive transfer of small numbers of DX5+ cells alleviates graft-versus-host disease in a murine model of semiallogeneic bone marrow transplantation: a potential role for NKT lymphocytes

Natural killer T (NKT) lymphocyte cells are a subset of regulatory lymphocytes with important immunemodulatory effects. Our aim was to evaluate the effect of transplantation of NKT lymphocytes on graft versus host disease (GVHD) in a murine model of semiallogeneic BMT. GVHD was generated by infusion of 2 x 107 splenocytes from C57BL/6 donor mice into irradiated (C57BL/6 x Balb/c)F1 recipient mice. Adoptive transfer of increasing numbers of DX5+ cells was performed. Recipient mice were followed for histological parameters of GVHD-associated liver, bowel, and cutaneous injury. Intrahepatic and intrasplenic lymphocytes were isolated and analyzed by FACS for CD4+ and CD8+ subpopulations. It was seen that adoptive transfer of 4.5 x 106 DX5+ cells significantly alleviated GVHD-related hepatic, bowel, and cutaneous injury, and improved survival (85% survival on day 28). In contrast, depletion of DX5+ cells led to severe GVHD-associated multiorgan injury and 100% mortality. A direct correlation with the number of transplanted DX5+ cells was noted (maximal effect with transplantation of 4.5 x 106 DX5+ cells). Tolerance induction was associated with an increased peripheral CD4/CD8 ratio, intrahepatic trapping of CD8 lymphocytes and a shift towards a Th2-type cytokine profile, manifested by decreased IL-12/IL10, IL-12/IL-4, IFNgamma/IL-10, and IFNgamma/IL-4 ratios. Transplantation of DX5+ cells holds promise as a novel therapeutic measure for GVHD.

Inhibitory Effects of Anti-Oxidants on Apoptosis of a Human Polyclonal T-Cell Line, MT-2, Induced by an Asbestos, Chrysotile-A

To clarify the effects of silica and silicates on cellular features of lymphocytes, a human T-lymphotropic virus type-1-immortalized polyclonal T-cell line, MT-2, was exposed to various concentrations of chrysotile-A, an asbestos classified as silicate. MT-2 cells underwent apoptosis in a dose- and time-dependent manner. The mitochondrial apoptotic pathway was activated during chrysotile-A-induced apoptosis of MT-2 cells, because of the phosphorylation of JNK and p38, increase of BAX and release of cytochrome-c from mitochondria to cytoplasma. In addition, anti-oxidants such as hydroxyl-radical excluders and capturers of superoxide and inhibitors of superoxide production effectively reduced the size of the apoptotic fraction in MT-2 cells cultured with chrysotile-A. These results indicate that the activation of reactive oxygen species may play a central role in asbestos-induced T-cell apoptosis, and anti-oxidants may help to prevent complications of pneumoconiosis.

Interleukin-10 polymorphisms in Spanish type 1 diabetes patients

The MHC accounts for half of the genetic susceptibility to type 1 diabetes (T1D). Evidence suggests that an imbalance in Th1/Th2 responses may play a key role in the development of autoimmune diabetes. Since interleukin-10 (IL-10) modulates immune and inflammatory responses and has been implicated in many autoimmune diseases, it seemed interesting to examine whether IL-10 polymorphisms participate in diabetes predisposition. In fact, this is the first association study investigating the role of the IL- 10 polymorphisms in susceptibility to T1D in a Caucasian population. Three promoter polymorphisms (-1082G/A, -819C/T, -592C/A) and two CA-repeat microsatellites (IL-10R and IL-10G at -4 and -1.1 kb) were tested in a case-control study with 294 T1D patients and 574 healthy controls. Our results prove a minor role of IL-10 in the autoimmune diabetes risk, although we found the same association trend with IL-10G(*)12 allele as was previously observed for multiple sclerosis and rheumatoid arthritis.

An integrated view of suppressor T cell subsets in immunoregulation

The immune system evolved to protect organisms from a virtually infinite variety of disease-causing agents but to avoid harmful responses to self. Because immune protective mechanisms include the elaboration of potent inflammatory molecules, antibodies, and killer cell activation--which together can not only destroy invading microorganisms, pathogenic autoreactive cells, and tumors, but also mortally injure normal cells--the immune system is inherently a "double-edged sword" and must be tightly regulated. Immune response regulation includes homeostatic mechanisms intrinsic to the activation and differentiation of antigen-triggered immunocompetent cells and extrinsic mechanisms mediated by suppressor cells. This review series will focus on recent advances indicating that distinct subsets of regulatory CD4+ and CD8+ T cells as well as NK T cells control the outgrowth of potentially pathogenic antigen-reactive T cells and will highlight the evidence that these suppressor T cells may play potentially important clinical roles in preventing and treating immune-mediated disease. Here we provide a historical overview of suppressor cells and the experimental basis for the existence of functionally and phenotypically distinct suppressor subsets. Finally, we will speculate on how the distinct suppressor cell subsets may function in concert to regulate immune responses.

Preconditioning of NOD mice with anti-CD8 mAb and costimulatory blockade enhances chimerism and tolerance and prevents diabetes, while depletion of alpha beta-TCR+ and CD4+ cells negates the effect

Bone marrow transplantation blocks diabetes pathogenesis and reverses autoimmunity in nonobese diabetic (NOD) mice. However, there is a greater barrier to engraftment in the context of autoimmunity. In the present study, we characterized which recipient cells influence engraftment in prediabetic NOD mice, with the goal to replace myelotoxic conditioning with antigen-specific deletion of reactive host cells. Preconditioning of NOD mice with anti-CD8 and anti-CD154 monoclonal antibodies (mAbs) synergistically enhanced engraftment and significantly reduced the minimum total body irradiation (TBI) dose for engraftment. Strikingly, preconditioning with anti-CD4 mAb significantly impaired engraftment, negating the beneficial effect of anti-CD8, and resulted in a requirement for more TBI-based conditioning compared with controls conditioned with TBI alone. Similarly, more TBI was required when anti-T-cell receptor beta (TCRbeta) mAb was administered as preconditioning. The addition of anti-CD152 to CD154 preconditioning abrogated the engraftment-enhancing effect of anti-CD154. Taken together, these data indicate a role for CD4+ regulatory T cells in vivo which require signaling via CD152 in the induction of chimerism and tolerance in NOD recipients. Notably, disease prevention and reversal of autoimmunity was absolutely correlated with the establishment of chimerism. These studies have important implications for the design of novel clinical approaches to treat type 1 diabetes.

Distinct homeostatic requirements of CD4+ and CD4- subsets of Valpha24-invariant natural killer T cells in humans

CD1d-restricted Valpha24-invariant natural killer T cells (iNKTs) are important in immunoregulation. CD4(+) and CD4(-) iNKTs develop with similar frequencies in murine thymus and depend on interleukin-15 (IL-15) in periphery. However, homeostatic requirements of iNKTs have not been analyzed in humans. We evaluated thymic production, peripheral dynamics, and functional maturation of human iNKTs. CD4(+) subset comprises 90% of iNKTs in mature thymocytes and cord blood (CB) but only 40% in adult blood. Using T-cell receptor excision circle (TREC) analysis, we directly measured in vivo replicative history of CD4(+) and CD4(-) iNKT cells. Compared to CD4(+), CD4(-) iNKTs contain fewer TRECs, express higher levels of IL-2Rbeta, and proliferate with higher rate in response to IL-15. In contrast, CD4(+) cells express higher levels of IL-7Ralpha and better respond to IL-7. Neither thymic nor CB iNKTs are able to produce cytokines unless they are induced to proliferate. Therefore, unlike in the mouse, human CD4(+) iNKTs are mainly supported by thymic output and limited peripheral expansion, whereas CD4(-) cells undergo extensive peripheral expansion, and both subsets develop their functions in periphery. These findings reveal important differences in homeostatic requirements and functional maturation between murine and human iNKTs that are to be considered for clinical purposes.

CD1d‐restricted T‐cell subsets and dendritic cell function in autoimmunity

CD1-restricted T cells have been shown to play a critical role in host defence, tumour surveillance, and maintenance of tolerance. However, immunologic outcomes resulting from activation of CD1d-restricted T cells can be either beneficial or deleterious. A major mechanism by which CD1d-restricted T cells are thought to exert immunoregulatory control is via effects on dendritic cell (DC) differentiation and migration. Important functional subsets of CD1d-restricted T cells are also known to exist and the potential implications for preferential subset activations are discussed.

Flow cytometry for natural killer T cells: multi-parameter methods for multifunctional cells

Valpha24-Jalpha18 invariant natural killer T cells (iNKT) are an evolutionary conserved sub-lineage of T cells with effector-memory phenotype that often express an NK cell surface antigen CD161 and is characterized by reactivity to self-glycolipids and alpha-galactosylceramide (alphaGalCer) that are presented by monomorphic HLA class-I-like molecule CD1d. Upon antigen recognition, iNKT cells can rapidly produce multiple cytokines and chemokines and regulate development of Th-2 and Th-1 immune responses. Potential importance of iNKT cells has been demonstrated in several animal models of infection diseases, autoimmunity, and cancer. Multi-parameter flow cytometry has been the main tool to study human and murine iNKT cells. Analysis of human iNKT cells is particularly demanding since their frequency among peripheral blood T cells is relatively low ranging from less than 0.01% to 1%, with a mean of about 0.1%. Herein, we discuss flow cytometry applications that are utilized for iNKT cell identification and enumeration, subset characterization, detection of intracellular cytokines, quantitative analysis of multiple secreted molecules, cell-mediated cytotoxicity, and migration.

Idiopathic chronic cough: association with organ specific autoimmune disease and bronchoalveolar lymphocytosis

BACKGROUND

We have recently reported a strong association between organ specific autoimmune disease and idiopathic chronic cough and have suggested that cough may be caused by airway inflammation secondary to aberrant homing of activated lymphocytes to the lung. An immunopathological study was undertaken to test the hypothesis that idiopathic chronic cough is associated with lymphocytic airway inflammation.

METHODS

Bronchoscopy, bronchial biopsies, bronchoalveolar lavage (BAL), and peripheral blood and BAL flow cytometry were performed in 19 patients with idiopathic chronic cough, 14 with explained chronic cough, and 11 normal subjects.

RESULTS

Organ specific autoimmune disease or positive autoantibodies were present in eight of the 19 patients with idiopathic cough, in one of the 14 patients with explained cough, and in one of the 11 normal subjects. Median BAL fluid differential lymphyocyte counts were significantly higher in patients with idiopathic cough (10.0%) than in normal subjects (6.3%, 95% confidence interval of difference 1.5 to 11.9, p = 0.01) or patients with explained cough (5.2%, 95% CI of difference 2.0 to 10.4, p = 0.001). There were no differences in bronchial biopsy T lymphocyte counts between the groups. The mean (SE) proportion of CD3+ peripheral blood mononuclear cells expressing CD4 was significantly higher in normal subjects than in patients with idiopathic cough (69 (3)% v 58 (3)%, mean difference 11%, 95% CI of difference 2 to 20, p<0.02) but not than those with explained chronic cough (63 (2)%). There were no differences in BAL T lymphocyte phenotype between groups.

CONCLUSION

BAL fluid lymphocytosis occurs in some patients with idiopathic chronic cough. The association of idiopathic chronic cough with organ specific autoimmune disease raises the possibility that this might be caused by lymphocyte homing from the primary site of autoimmune inflammation or the result of an autoimmune process in the lung.

Adoptive transfer of ex vivo immune-programmed NKT lymphocytes alleviates immune-mediated colitis

T lymphocyte-expressing natural killer (NK) cell markers (NKT cells) play a role in immune regulation. Our aim was to evaluate the in vivo effect of adoptive transfer of immune-programmed NKT cells. Colitis was induced in C57/B6 mice by 2,4,6-trinitrobenzenesulfonic acid. NKT, CD4, CD8 lymphocytes, and dendritic cells (DC) were prepared from spleens of naive mice, animals with colitis, and animals with colitis that were orally tolerized. Subsets of splenocytes, NKT, CD4, and CD8 and NKT+CD4, NKT+CD8, and NKT+DC lymphocytes were prepared. Assessment of the T helper cell type 1 (Th1)/Th2 cytokine secretion paradigm in vitro was performed before and following exposure to the antigen. Adoptive transfer of ex vivo immune-programmed lymphocytes from each group was performed into recipient mice, followed by colitis induction. Ex vivo exposure of NKT cells harvested from mice with colitis-to-colitis proteins [colitis-extracted proteins (CEP)] led to a Th2 cytokine shift. The interleukin (IL)-4/interferon-gamma (IFN-gamma) ratio increased for NKT harvested from colitis-harboring mice following exposure to CEP. Adoptive transfer of NKT lymphocytes harvested from colitis-harboring mice, which were ex vivo-educated, significantly alleviated experimental colitis in vivo. Intrahepatic NKT lymphocytes increased significantly in mice transplanted with NKT lymphocytes harvested from colitis-harboring donor mice, which were ex vivo-exposed to CEP, similar to mice transplanted with NKT lymphocytes harvested from tolerized donors. Exposure of NKT cells to the disease-target antigen induced a significant increase in the IL-4/IFN-gamma cytokine ratio. Adoptive transfer of a relatively small number of immune-programmed NKT cells induced a systemic Th1 to Th2-immune shift and alleviated immune-mediated colitis.

Therapeutic activation of Valpha24+Vbeta11+ NKT cells in human subjects results in highly coordinated secondary activation of acquired and innate immunity

Human Valpha24+Vbeta11+ natural killer T (NKT) cells are a distinct CD1d-restricted lymphoid subset specifically and potently activated by alpha-galactosylceramide (alpha-GalCer) (KRN7000) presented by CD1d on antigen-presenting cells. Preclinical models show that activation of Valpha24+Vbeta11+ NKT cells induces effective antitumor immune responses and potentially important secondary immune effects, including activation of conventional T cells and NK cells. We describe the first clinical trial of cancer immune therapy with alpha-GalCer-pulsed CD1d-expressing dendritic cells. The results show that this therapy has substantial, rapid, and highly reproducible specific effects on Valpha24+Vbeta11+ NKT cells and provide the first human in vivo evidence that Valpha24+Vbeta11+ NKT cell stimulation leads to activation of both innate and acquired immunity, resulting in modulation of NK, T-, and B-cell numbers and increased serum interferon-gamma. We present the first clinical evidence that Valpha24+Vbeta11+ NKT cell memory produces faster, more vigorous secondary immune responses by innate and acquired immunity upon restimulation.

Activation of natural killer T cells by alpha-galactosylceramide rapidly induces the full maturation of dendritic cells in vivo and thereby acts as an adjuvant for combined CD4 and CD8 T cell immunity to a coadministered protein

The maturation of dendritic cells (DCs) allows these antigen-presenting cells to initiate immunity. We pursued this concept in situ by studying the adjuvant action of alpha-galactosylceramide (alphaGalCer) in mice. A single i.v. injection of glycolipid induced the full maturation of splenic DCs, beginning within 4 h. Maturation was manifest by marked increases in costimulator and major histocompatibility complex class II expression, interferon (IFN)-gamma production, and stimulation of the mixed leukocyte reaction. These changes were not induced directly by alphaGalCer but required natural killer T (NKT) cells acting independently of the MyD88 adaptor protein. To establish that DC maturation was responsible for the adjuvant role of alphaGalCer, mice were given alphaGalCer together with soluble or cell-associated ovalbumin antigen. Th1 type CD4+ and CD8+ T cell responses developed, and the mice became resistant to challenge with ovalbumin-expressing tumor. DCs from mice given ovalbumin plus adjuvant, but not the non-DCs, stimulated ovalbumin-specific proliferative responses and importantly, induced antigen-specific, IFN-gamma producing, CD4+ and CD8+ T cells upon transfer into naive animals. In the latter instance, immune priming did not require further exposure to ovalbumin, alphaGalCer, NKT, or NK cells. Therefore a single dose of alphaGalCer i.v. rapidly stimulates the full maturation of DCs in situ, and this accounts for the induction of combined Th1 CD4+ and CD8+ T cell immunity to a coadministered protein.

Gene- and cell-based therapeutics for type I diabetes mellitus

Type 1 diabetes mellitus, an autoimmune disorder is an attractive candidate for gene and cell-based therapy. From the use of gene-engineered immune cells to induce hyporesponsiveness to autoantigens to islet and beta cell surrogate transplants expressing immunoregulatory genes to provide a local pocket of immune privilege, these strategies have demonstrated proof of concept to the point where translational studies can be initiated. Nonetheless, along with the proof of concept, a number of important issues have been raised by the choice of vector and expression system as well as the point of intervention; prophylactic or therapeutic. An assessment of the current state of the science and potential leads to the conclusion that some strategies are ready for safety trials while others require varying degrees of technical and conceptual refinement.

IL-4 expression delays eosinophil-independent vasculopathy and fibrosis during allograft rejection in the mouse

Transplant vasculopathy in the mouse is thought to be dependent on IL-4 and mediated by IL-5 and eosinophils, whereas in the rat and human systems, IL-4 is associated with the absence of transplant vasculopathy and down-regulation of a Th1-type response. In this study we tested the possibility that the apparent difference in the role of IL-4 in transplant vasculopathy is related to protocol differences rather than to the species being studied. Using a protocol that closely resembles that used in rat and human studies, we developed a model of transplant vasculopathy in the mouse that is associated with Th1-type cytokines and independent of IL-5 and eosinophil infiltration. In this model IL-4 promotes a significant delay in vasculopathy in the graft (P = 0.04) and a decrease in the incidence of allograft rejection (P = 0.02). The data suggest that the role of IL-4 in transplant vasculopathy can be controlled by the protocol used to treat the transplant recipient.

NKT and T cells: coordinate regulation of NK-like phenotype and cytokine production

A maturation-dependent change in phenotype and cytokine production from relatively immature CD161(-) or CD161(+), IL-13(+)IL-4(+), IFN-gamma(-), to mature CD161(+)CD56(+) IFN-gamma(+) cells occurs in primary human alpha-galactosyl ceramide-reactive CD1d-restricted natural killer T (NKT) cells under the control of IL-12 and other monokines. Modulation of this process upon alpha-galactosyl ceramide stimulation explains the opposite roles of NKT cells to drive type 1 and type 2 immune responses. Because the same developmental changes occurred and were similarly regulated in T cells, the data establish that NKT cells should no longer be considered a functionally unique regulatory subset. However, the results of their analysis can be taken as a model for immunotherapeutic approaches with T cells for which a nominal or surrogate antigen is defined.