Islet-cell antigen-reactive T cells show different expansion rates and Th1/Th2 differentiation in type 1 diabetic patients and healthy controls

The low frequency of islet-cell antigen-reactive T cells in type 1 diabetes makes their direct measurement difficult. Commonly used in vitro expansion could alter in vivo frequencies and Th1/Th2 differentiation states. Using IFN-gamma/IL-4 double color ELISPOT, we tested longitudinally the reactivity of PBMC from HLA-matched diabetic patients and healthy controls to GAD65, IA-2, and proinsulin peptides ex vivo and after in vitro culture. The peptide-reactive T cells showed IFN-gamma bias in the patients' PBMC in the primary assay. During in vitro culture, both IFN-gamma- and IL-4-producing cells were induced in controls, suggesting that the precursor cells were uncommitted naive T cells in vivo. In contrast, in diabetic patients, the ex vivo IFN-gamma response was conserved during culture, suggesting their Th1 commitment. Using CFSE-dye-dilution, we demonstrate that naive T cells expand in vitro at a faster rate than memory cells, which might account for the differences in expansion rates between diabetic patients and controls.     

Dissection of signaling cascades through gp130 in vivo: reciprocal roles for STAT3- and SHP2-mediated signals in immune responses

While CD28 is critical for expansion of naive T cells, recent evidence suggests that the activation of effector T cells is largely independent of CD28/B7. We suggest that ICOS, the third member of the CD28/CTLA-4 family, plays an important role in production of IL-2, IL-4, IL-5, and IFNgamma from recently activated T cells and contributes to T cell-dependent B help in vivo. Inhibition of ICOS attenuates lung mucosal inflammation induced by Th2 but not Th1 effector populations. Our data indicate a critical function for the third member of the CD28 family in T cell-dependent immune responses.     

Cytotoxic T cells to an epitope in the islet autoantigen IA-2 are not disease-specific

Cytotoxic CD8 T lymphocytes (CTL) are effectors of pancreatic islet beta-cell destruction in type 1 diabetes but, with the exception of a single report, CTL to islet antigen peptides have not been identified. We used autologous blood monocyte-derived dendritic cells to elicit HLA-A2-restricted CTL to a peptide, MVWESGCTV (aa 797-805), that is contiguous with a dominant CD4 T-cell epitope in the islet antigen tyrosine phosphatase IA-2. IA-2 peptide-specific CTL activity measured as 51Cr release from autologous lymphoblasts was detected in 2/6 islet antibody-positive relatives at high risk for type 1 diabetes but also in 2/6 closely HLA-matched controls. All subjects had CTL activity to an HLA-A2-restricted Epstein-Barr virus peptide. CTL to the IA-2 self-peptide were therefore not disease-specific, consistent with other evidence that autoreactive T cells are present in healthy individuals.     

Chromatin remodeling at the Th2 cytokine gene loci in human type 2 helper T cells

The differentiation of mouse na?ve CD4 T cells into type 2 helper (Th2) cells is accompanied by chromatin remodeling at the nucleosomes associated with the IL-4, IL-13 and IL-5 genes. However, little is known about how chromatin remodeling of these Th2 cytokine gene loci occurs in human Th2 cells. We herein established an in vitro culture system in which both Th1 and Th2 cells are efficiently differentiated from human peripheral blood na?ve CD4 T cells. This system allowed us to investigate the chromatin status at the Th2 cytokine gene loci and the IFNgamma locus in human Th2 and Th1 cells, respectively. In typical individuals, the chromatin remodeling indicated by the induction of hyper-acetylation of histone H3 lysine 9 and hyper-methylation of histone H3 lysine 4 was induced at the whole Th2 cytokine gene loci in developing Th2 cells. We more precisely assessed the methylation status of histone H3 lysine 4 at the Th2 cytokine gene loci (IL-5 exon 3, IL-5 promoter, IL-5/RAD50 intergenic region, RAD50 promoter, CGRE, CNS1, IL-13 promoter, IL-4 promoter, and VA enhancer regions) and the IFNgamma locus in developing Th1 and Th2 cells prepared from 20 healthy volunteers. Th2-cell specific chromatin remodeling was induced at most of the Th2 cytokine gene loci. In parallel with the induction of chromatin remodeling, GATA3 mRNA was preferentially expressed in developing Th2 cells, whereas T-bet, HLX and ROG mRNA was selectively expressed in developing Th1 cells.     

Transcriptional regulation of Th17 cell differentiation

The paradigm of effector T helper cell differentiation into either Th1 or Th2 lineages has been profoundly shaken by the discovery of T cells that secrete IL-17 and other inflammatory cytokines. This subset, referred to as Th17, is centrally involved in autoimmune disease and is important in host defense at mucosal surfaces. In mouse, a series of cytokines, including IL-6, IL-21, IL-23, and TGF-beta, function sequentially or synergistically to induce the Th17 lineage. Other cytokines, including IL-2, IL-4, IFNgamma, and IL-27, inhibit differentiation of this lineage. Here we review how the nuclear orphan receptor RORgammat functions to coordinate the diverse cytokine-induced signals and thus controls Th17 cell differentiation.     

High levels of type 2 cytokine-producing cells in chronic fatigue syndrome

The aetiology of chronic fatigue syndrome (CFS) is not known. However, it has been suggested that CFS may be associated with underlying immune activation resulting in a Th2-type response. We measured intracellular production of interferon (IFN)-gamma and interleukin (IL)-2; type 1 cytokines), IL-4 (type 2) and IL-10 (regulatory) by both polyclonally stimulated and non-stimulated CD4 and CD8 lymphocytes from patients with CFS and control subjects by flow cytometry. After polyclonal activation we found evidence of a significant bias towards Th2- and Tc2-type immune responses in CFS compared to controls. In contrast, levels of IFN-gamma, IL-2 and IL-10-producing cells were similar in both study groups. Non-stimulated cultures revealed significantly higher levels of T cells producing IFN-gamma or IL-4 in CFS patients. Concluding, we show evidence for an effector memory cell bias towards type 2 responsiveness in patients with CFS, as well as ongoing type 0 immune activation in unstimulated cultures of peripheral blood cells.     

Rapid development of Th2 activity during T cell priming

The paradigm of T helper-1 (Th-1) and Th-2 cells developing from non-committed naive precursors is firmly established. Th1 cells are characterized by IFNgamma production and, in mice, the selective switching to IgG2a. Conversely IL-4 production and selective switching to IgG1 and IgE characterize Th2 cells. Analysis of Th2 induction in vitro indicates that this polarization develops gradually in T cells activated by anti-CD3 in the presence of IL-4; conversely anti-CD3 and IFNgamma induce Th1 cells. In this report, we explore evidence that indicates that the T helper cell polarization in vivo cannot solely be explained by the cytokine environment. This is provided by studying the early acquisition of Th1 and Th2 activities during responses to a mixture of Th1 and Th2-inducing antigens. It is shown that these divergent forms of T cell help can rapidly develop in cells within a single lymph node. It is argued that early polarization to show Th-1 or Th-2 behavior can be induced by signals delivered during cognate interaction between virgin T cells and dendritic cells, in the absence of type 1 or type 2 cytokines. This contrasts with the critical role of the cytokines in reinforcing the Th-phenotype and selectively expanding T helper clones.     

Anti-GAD65 reactive peripheral blood mononuclear cells in the pathogenesis of cystic fibrosis related diabetes mellitus

OBJECTIVE: A role of autoreactive T cells for type 1 diabetes pathogenesis is considered crucial. In our pilot study we addressed if autoreactive mononuclear cells are present also in peripheral blood of patients with other specific forms of diabetes as cystic fibrosis related diabetes (CFRD). METHODS: Cellular immune responses to a known beta-cell autoantigen (GAD65 and GAD65 derived peptides) were analysed by ELISPOT (IFN-gamma) and by protein microarray analysis in four patients suffering from CFRD, in four cystic fibrosis (CF) patients without diabetes, in eight type 1 diabetes patients (without CF) and in four healthy controls. RESULTS: Response to the autoantigen GAD65 (protein and peptides) was observed in 7/8 patients suffering from CF and in all type 1 diabetes patients. Post-stimulation production of Th1 cytokines (IFN-gamma, TNF-beta) was observed in 2/4 CFRD, 1/4 CF patients and in 7/8 type 1 diabetes patients. All these patients carry prodiabetogenic HLA-DQ genotype. Th2- and Th3 type of cytokine pattern was observed in 2/4 CF patients. Production of IL-8 was observed in the third CFRD as well as in the third CF patient and in 1/8 type 1 diabetes patient and borderline production of this chemokine was also observed in 2/4 healthy controls. No reaction was observed in the other 2/4 healthy controls and in the fourth CFRD patient who carried a strongly protective genotype and did not produce autoantibodies. The most potent peptide of GAD65 was amino acids 509-528. CONCLUSIONS: We consider our observations as a sign of a reaction directed against the self-antigen GAD65 that are closely connected to type 1 diabetes. In CF patients who do not develop diabetes autoreactive mechanisms are very probably efficiently suppressed by immune self-tolerance mechanisms. CFRD patients are a heterogenic group. To disclose those who may display features of autoimmune diabetes could have an impact for their therapy and prognosis.     

Quantitative and qualitative analysis of the balance between type 1 and type 2 cytokine-producing CD8(-) and CD8(+) T cells in systemic lupus erythematosus

The production of type 1 (IFN-gamma, IL-2) and type 2 (IL-4, IL-5, IL-10, IL-13) cytokines by CD8(-) and CD8(+) T cells from systemic lupus erythematosus (SLE) patients and normal subjects was investigated using an intracellular cytokine-staining technique. This flow cytometric method facilitates analysis of both surface markers and cytoplasmic cytokines, after a short term (6 h) culture with or without phorbol myristate acetate and ionomycin (PMA/I) stimulation. In SLE patients, more unstimulated T cells produced IL-10 in comparison with controls; other cytokines were not detected in unstimulated cells. The percentage of IL-10-secreting T cells did not significantly increase after PMA/I stimulation of cells from SLE patients. The mean intensity of fluorescence (MIF) of intracellular IL-4 staining was significantly higher in CD8(-) T cells of SLE patients than controls. Significantly fewer CD8(-) and CD8(+) T cells from SLE patients secreted IFN-gamma after PMA/I stimulation compared with controls. The MIF and percentage of IL-2, IL-5, and IL-13-secreting cell subsets were not significantly different between SLE patients and controls. These findings indicate that T cells of SLE patients are already stimulated to produce IL-10 in vivo, which may result in downregulation of IFN-gamma secreting CD8(-) and CD8(+) T cells observed following PMA/I stimulation. Thus, the population size of Th1 and Tc1 cells are reduced in SLE patients whereas the effector function of Th2 cells, with respect to IL-4 production, is enhanced in SLE patients. Furthermore, although the balance between Th1/Th2 and between Tc1/Tc2 is disrupted in SLE patients, it is significantly biased in favour of the Th2 subset only.     

FTY720 ameliorates oxazolone colitis in mice by directly affecting T helper type 2 functions

The sphingosine-1-phosphate analogue FTY720 is known to alter migration and homing of lymphocytes via sphingosine-1-phosphate receptors. However, several studies indicate that its mode of action is more complex and that FTY720 may also directly influence cytokine effector functions. Therefore, we studied the effect of FTY720 in T helper type (Th2)-mediated oxazolone-induced colitis in mice. Following rectal oxazolone instillation, Th2 cells producing IL-13 induce a progressive colitis resembling human ulcerative colitis. A rectal enema of oxazolone [90 mg/kg body weight] was applied to BALB/c mice. FTY720 was administered i.p. from day 0 to 3 or from day 3 to 5 following the instillation of the haptenating agent. Assessment of severity of colitis was performed daily. FTY720 plasma levels were detected using LC-MS/MS-analysis. Colon tissue was analyzed macroscopically and microscopically, myeloperoxidase activity as well as cytokine levels of lamina propria CD4(+) T-cells and T1/ST2 expression were determined. Treatment with FTY720 prominently reduced the clinical and histopathologic severity of oxazolone-induced colitis, abrogating body weight loss, diarrhea, and macroscopic and microscopic intestinal inflammation. The therapeutic effects of FTY720 were associated with a prominent reduction of the key effector Th2 cytokines IL-13, IL-4 and IL-5. Strikingly, FTY720 inhibited GATA3 and T1/ST2 expression which represent highly relevant markers for Th2 differentiation and Th2 effector function, respectively. Our data provide the first evidence that FTY720 exhibits beneficial prophylactic as well as therapeutic effects in Th2-mediated experimental colitis by directly affecting Th2 cytokine profiles probably by reducing T1/ST2, thus offering a new auspicious therapeutic instrument for the treatment of human ulcerative colitis.     

Anti-GAD65 reactive peripheral blood mononuclear cells in the pathogenesis of cystic fibrosis related diabetes mellitus

Objective: A role of autoreactive T cells for type 1 diabetes pathogenesis is considered crucial. In our pilot study we addressed if autoreactive mononuclear cells are present also in peripheral blood of patients with other specific forms of diabetes as cystic fibrosis related diabetes (CFRD). Methods: Cellular immune responses to a known β-cell autoantigen (GAD65 and GAD65 derived peptides) were analysed by ELISPOT (IFN-γ) and by protein microarray analysis in four patients suffering from CFRD, in four cystic fibrosis (CF) patients without diabetes, in eight type 1 diabetes patients (without CF) and in four healthy controls. Results: Response to the autoantigen GAD65 (protein and peptides) was observed in 7/8 patients suffering from CF and in all type 1 diabetes patients. Post-stimulation production of Th1 cytokines (IFN-γ, TNF-β) was observed in 2/4 CFRD, 1/4 CF patients and in 7/8 type 1 diabetes patients. All these patients carry prodiabetogenic HLA-DQ genotype. Th2- and Th3 type of cytokine pattern was observed in 2/4 CF patients. Production of IL-8 was observed in the third CFRD as well as in the third CF patient and in 1/8 type 1 diabetes patient and borderline production of this chemokine was also observed in 2/4 healthy controls. No reaction was observed in the other 2/4 healthy controls and in the fourth CFRD patient who carried a strongly protective genotype and did not produce autoantibodies. The most potent peptide of GAD65 was amino acids 509–528. Conclusions: We consider our observations as a sign of a reaction directed against the self-antigen GAD65 that are closely connected to type 1 diabetes. In CF patients who do not develop diabetes autoreactive mechanisms are very probably efficiently suppressed by immune self-tolerance mechanisms. CFRD patients are a heterogenic group. To disclose those who may display features of autoimmune diabetes could have an impact for their therapy and prognosis.     

CD4 T cells and their antigens in the pathogenesis of autoimmune diabetes

Pathogenesis of type 1 diabetes (T1D) is mediated by effector T cells and CD4 Th1 and Th17T cells have important roles in this process. While effector function of Th1 cells is well established, because of their inherent plasticity Th17 cells have been more controversial. Th17 cells contribute to pathogenicity, but several studies indicate that Th17 cells transfer disease through conversion to Th1 cells in vivo. CD4T cells are attracted to islets by β-cell antigens which include insulin and the two new autoantigens, chromogranin A and islet amyloid polypeptide, all proteins of the secretory granule. Peptides of insulin and ChgA bind to the NOD class II molecule in an unconventional manner and since autoantigenic peptides may typically bind to MHC with low affinity, it is postulated that post-translational modifications of β-cell peptides could contribute to the interaction between peptides, MHC, and the autoreactive TCR.     

CD4 T cell differentiation in type 1 diabetes

Susceptibility to type 1 diabetes is associated strongly with human leucocyte antigen (HLA) genes, implicating T cells in disease pathogenesis. In humans, CD8 T cells predominantly infiltrate the islets, yet their activation and propagation probably requires CD4 T cell help. CD4 T cells can select from several differentiation fates following activation, and this choice has profound consequences for their subsequent cytokine production and migratory potential. In turn, these features dictate which other immune cell types T cells interact with and influence, thereby determining downstream effector functions. Obtaining an accurate picture of the type of CD4 T cell differentiation associated with a particular immune‐mediated disease therefore constitutes an important clue when planning intervention strategies. Early models of T cell differentiation focused on the dichotomy between T helper type 1 (Th1) and Th2 responses, with type 1 diabetes (T1D) being viewed mainly as a Th1‐mediated pathology. However, several additional fate choices have emerged in recent years, including Th17 cells and follicular helper T cells. Here we revisit the issue of T cell differentiation in autoimmune diabetes, highlighting new evidence from both mouse models and patient samples. We assess the strengths and the weaknesses of the Th1 paradigm, review the data on interleukin (IL)‐17 production in type 1 diabetes and discuss emerging evidence for the roles of IL‐21 and follicular helper T cells in this disease setting. A better understanding of the phenotype of CD4 T cells in T1D will undoubtedly inform biomarker development, improve patient stratification and potentially reveal new targets for therapeutic intervention.     

GAD65-Reactive T cells in a Non-diabetic Stiff-man Syndrome Patient

GAD65 (glutamic acid decarboxylase) is an important autoantigen in both type 1 (insulin-dependent) diabetes mellitus (IDDM) and the neurological autoimmune disease stiff-man syndrome (SMS), and is expressed in pancreatic islets as well as the nervous system. Still, only 30% of SMS patients also have type 1 diabetes. To study regulation of T cell responsiveness to GAD65, we investigated a non-diabetic SMS patient with HLA-DR3/7 (predisposing to type 1 diabetes) and high levels of type 1 diabetes-associated autoantibodies against GAD65 and islet cells, and compared the results with those of her diabetic son and two other SMS patients. T cell responses to GAD65 were repeatedly absent in primary stimulation, whereas IA-2, islet antigen and tetanus toxoid induced significant T cell proliferation. However, after in vitro restimulation, GAD65 reactive T cell lines and clones were obtained that were HLA-DR3 restricted, and cross-reactive with a homogenate of purified human pancreatic islets. These T cells produced the immunoregulatory cytokine IL-10 in combination with IFN-gamma and IL-4 (Th0). The dominant T cell epitope was mapped to the central region of GAD65. Although no primary response to whole GAD65 was detectable, the naturally processed GAD65 peptide epitope was recognized vigorously in the primary stimulation assay. The lack of detectable primary T cell responses to GAD65, together with the GAD65-specific cytokine production of restimulated T cells, suggest that GAD65-specific cellular autoimmunity in this patient is suppressed and may be related to the absence of diabetes despite humoral autoreactivity and genetic predisposition.     

Characterization of NKT Cells in Human Peripheral Blood and Decidual Lymphocytes

PROBLEM: To examine whether natural killer (NKT) cells are present in human pregnancy decidua. METHOD OF STUDY: We calculated the percentage of CD3+CD161+Valpha 24+-NKT cells in peripheral blood and early pregnancy decidua, and analyzed intracellular cytokines, interleukin (IL)-4 and interferon (IFN)gamma in NKT cells using flow cytometry. RESULTS: A distinct subset of CD3+ CD161+ lymphocytes expressing an invariant antigen receptor encoded by the Valpha24 and Vbeta11 segment was accumulated in the decidua. In pregnant subjects the percentages of NKT cells were significantly increased in the decidua compared with peripheral blood. Both NKT cells in the decidua and the peripheral blood had an ability to rapidly produce cytokine associated with Th1 (IFNgamma) and Th2 (IL-4). Interestingly, the percentages of IL-4 and IFNgamma producing NKT cells were significantly higher in the decidua compared with the peripheral blood. CONCLUSIONS: These findings suggest that NKT cells might control the Th1/Th2 balance by producing IL-4 and IFNgamma at the feto-maternal interface.     

Gamma interferon (IFN-gamma), tumor necrosis factor alpha (TNF-alpha) and interleukins 2, 4 and 6 (IL-2, IL-4, IL-6) in cervical-uterine cells of intraepithelial neoplasia: a preliminary report

The purpose of this work was to determine the expression of type Th1 cytokines: IL-2 and IFNgamma, and Th2: IL-4 and IL-6, as well as TNF-alpha in patients with precancerous lesions of the uterine cervix and their relationship with the human papiloma virus (HPV). 30 patients with precancerous lesions (NIC 1: 70%, NIC 2: 16.7% and NIC 3: 1.3%) and 9 normal controls were studied. A clinical history, gynecological evaluation, cytology and an uterine biopsy were carried out in each patient and control. PCR was used for the diagnosis of HPV. IFN-gamma expression (positive cells/field) was increased in patients with NIC (5.06 +/- 4.7 vs 0 in the control group; p < 0.05). TNFa was a little higher in pathologycal tissues than in the controls (5.23 +/- 3.63 vs 1.55 +/- 2.65; p < 0.05). IL-2 was higher in pathologycal cases than in the controls (8.73 +/- 5.23 vs 0.33 +/- 1, p < 0.05). IL-4 were expressed in both, patients and controls (6.53 +/- 5.23 vs 5.77 +/- 7.32). IL-6 was also higher in patients (4.63 +/- 3.34 vs 0.77 +/- 2.33; p < 0.05). When the HPV status was considered, only IFN-gamma (p < 0.05) and IL-2 (p < 0.05) were significantly higher in HPV positive patients (n = 4) compared to controls. When HPV+ patients were compared with HPV- patients, only IFNgamma was significant (11.5 +/- 5 vs 4.07 +/- 3.8; p < 0.05). In conclusion, Type Th1 immune response prevails in patients with precancerous lesions, whether they are HPV positive or not.     

Type 1 and type 2 cytokine dysregulation in human infectious, neoplastic, and inflammatory diseases.

In the mid-1980s, Mosmann, Coffman, and their colleagues discovered that murine CD4+ helper T-cell clones could be distinguished by the cytokines they synthesized. The isolation of human Th1 and Th2 clones by Romagnani and coworkers in the early 1990s has led to a large number of reports on the effects of Th1 and Th2 on the human immune system. More recently, cells other than CD4+ T cells, including CD8+ T cells, monocytes, NK cells, B cells, eosinophils, mast cells, basophils, and other cells, have been shown to be capable of producing "Th1" and "Th2" cytokines. In this review, we examine the literature on human diseases, using the nomenclature of type 1 (Th1-like) and type 2 (Th2-like) cytokines, which includes all cell types producing these cytokines rather than only CD4+ T cells. Type 1 cytokines include interleukin-2 (IL-2), gamma interferon, IL-12 and tumor necrosis factor beta, while type 2 cytokines include IL-4, IL-5, IL-6, IL-10, and IL-13. In general, type 1 cytokines favor the development of a strong cellular immune response whereas type 2 cytokines favor a strong humoral immune response. Some of these type 1 and type 2 cytokines are cross-regulatory. For example, gamma interferon and IL-12 decrease the levels of type 2 cytokines whereas IL-4 and IL-10 decrease the levels of type 1 cytokines. We use this cytokine perspective to examine human diseases including infections due to viruses, bacteria, parasites, and fungi, as well as selected neoplastic, atopic, rheumatologic, autoimmune, and idiopathic-inflammatory conditions. Clinically, type 1 cytokine-predominant responses should be suspected in any delayed-type hypersensitivity-like granulomatous reactions and in infections with intracellular pathogens, whereas conditions involving hypergammaglobulinemia, increased immunoglobulin E levels, and/or eosinophilia are suggestive of type 2 cytokine-predominant conditions. If this immunologic concept is relevant to human diseases, the potential exists for novel cytokine-based therapies and novel cytokine-directed preventive vaccines for such diseases.     

Do T helpers 1 and 2 recognize different class II MHC molecules? Humoral and cellular immune responses to soluble allergen from Aspergillus fumigatus Asp f2

Cellular signals leading to T helper (Th)1/Th2 shift are not well known. Here we demonstrate that Th1 possibly recognizes peptides presented by the IE molecule of MHC class II while Th2 is activated by the recognition of peptides presented by the IA molecule. BALB/c mice immunized with Asp f2 developed stable IA-restricted Th2 immune response to the 12th day after immunization, as analyzed by IL-2 production. On the contrary, early Th0 cells did not secrete IL-2 upon Asp f2 stimulation but did produce a high level of IL-2 if stimulated in the presence of anti-IA Abs. This effect of anti-IA Abs on early Th0 cells was both MHC IE and CD4(+) cell restricted. In vivo blocking of Asp f2 peptide presentation by the IA molecule led to the formation of antigen-specific cytotoxicity as demonstrated using immune splenocytes as effector cells and Asp f2 loaded P815 cells as targets.