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Type 1 diabetes (T1D) is an autoimmune disease with both genetic and environmental components. More than 60 genes have been identified to affect the risk of T1D, with the HLA [...], Evaluating risk of developing type 1 diabetes (T1D) depends on determining an individual's HLA type, especially of the HLA DRB1 and DQB1 alleles. Individuals positive for HLA-DRB1*03 (DR3) or HLA-DRB1*04 (DR4) with DQB1*03:02 (DQ8) have the highest risk of developing T1D. Currently, HLA typing methods are relatively expensive and time consuming. We sought to determine the minimum number of single nucleotide polymorphisms (SNPs) that could rapidly define the HLA-DR types relevant to T1D, namely, DR3/4, DR3/3, DR4/4, DR3/X, DR4/X, and DRX/X (where X is neither DR3 nor DR4), and could distinguish the highest-risk DR4 type (DR4-DQ8) as well as the nonT1D-associated DR4-DQBI*03:01 type. We analyzed 19,035 SNPs of 10,579 subjects (7,405 from a discovery set and 3,174 from a validation set) from the Type 1 Diabetes Genetics Consortium and developed a novel machine learning method to select as few as three SNPs that could define the HLA-DR and HLA-DQ types accurately. The overall accuracy was 99.3%, area under curve was 0.997, true-positive rates were >0.99, and false-positive rates were

Type 1 diabetes (T1D) is characterized by insulin deficiency secondary to autoimmune-mediated destruction of insulin-producing β-cells in the pancreatic islets. Less than 50% of the familial clustering in T1D can [...], OBJECTIVE--Excess accumulation of advanced glycation end products (AGEs) contributes to aging and chronic diseases. We aimed to obtain evidence that exposure to AGEs plays a role in the development of type 1 diabetes (T1D). RESEARCH DESIGN AND METHODS--The effect of AGEs was examined on insulin secretion by MIN6N8 cells and mouse islets and in vivo in three separate rodent models: AGE-injected or high AGE-fed Sprague-Dawley rats and nonobese diabetic (NODLt) mice. Rodents were also treated with the AGE-lowering agent alagebriunm. RESULTS--β-Cells exposed to AGEs displayed acute glucose-stimulated insulin secretory defects, mitochondrial abnormalities including excess superoxide generation, a decline in ATP content, loss of MnSOD activity, reduced calcium flux, and increased glucose uptake, all of which were improved with alagebrium treatment or with MnSOD adenoviral overexpression. Isolated mouse islets exposed to AGEs had decreased glucose-stimulated insulin secretion, increased mitochondrial superoxide production, and depletion of ATP content, which were improved with alagebrium or with MnTBAP, an SOD mimetic. In rats, transient or chronic exposure to AGEs caused progressive insulin secretory defects, superoxide generation, and β-cell death, ameliorated with alagebrium. NODLt mice had increased circulating AGEs in association with an increase in islet mitochondrial superoxide generation, which was prevented by alagebrium, which also reduced the incidence of autoimmune diabetes. Finally, at-risk children who progressed to TID had higher AGE concentrations than matched nonprogressors. CONCLUSIONS--These findings demonstrate that AGEs directly cause insulin secretory defects, most likely by impairing mitochondrial function, which may contribute to the development of T1D.

Type 1 diabetes is an autoimmune disease that destroys insulin-producing β-cells in the islets of the pancreas. Studies in the NOD mouse model of spontaneous type 1 diabetes provide compelling [...], OBJECTIVE--Insulin in pancreatic [3-cells is a target of autoimmunity in type 1 diabetes. In the NOD mouse model of type 1 diabetes, oral or nasal administration of insulin induces immune tolerance to insulin and protects against autoimmune diabetes. Evidence for tolerance to mucosally administered insulin or other autoantigens is poorly documented in humans. Adults with recent-onset type 1 diabetes in whom the disease process is subacute afford an opportunity to determine whether mucosal insulin induces tolerance to insulin subsequently injected for treatment. RESEARCH DESIGN AND METIIODS--We randomized 52 adults with recent-onset, noninsulin-requiring type 1 diabetes to nasal insulin or placebo for 12 months. Fasting blood glucose and serum C-peptide, glucagon-stimulated serum C-peptide, and serum antibodies to islet antigens were monitored three times monthly for 24 months. An enhanced ELISpot assay was used to measure the T-cell response to human proinsulin. RESULTS--β-Cell function declined by 35% overall, and 23 of 52 participants (44%) progressed to insulin treatment. Metabolic parameters remained similar between nasal insulin and placebo groups, but the insulin antibody response to injected insulin was significantly blunted in a sustained manner in those who had received nasal insulin. In a small cohort, the interferon-γ response of blood T-cells to proinsulin was suppressed after nasal insulin. CONCLUSIONS--Although nasal insulin did not retard loss of residual β-cell function in adults with established type 1 diabetes, evidence that it induced immune tolerance to insulin provides a rationale for its application to prevent diabetes in at-risk individuals. Diabetes 60:1237-1245, 2011

Nonobese diabetic (NOD) mice spontaneously develop autoimmune diabetes, driven by progressive inflammatory dysregulation. Autoimmune inflammation begins at ~4 weeks of age with peri-insulitis and infiltration of macrophages and dendritic cells [...], OBJECTIVE--The effectiveness of tolerizing immunotherapeutic strategies, such as anti-CD40L or dendritic cells (DCs), is greater when administered to young nonobese diabetic (NOD) mice than at peak insulitis. [RelB.sup.lo] DCs, generated in the presence of an nuclear factor-κB inhibitor, induce T-regulatory (Treg) cells and suppress inflammation in a model of rheumatoid arthritis. Interleukin (IL)-1β is overexpressed in humans and mice at risk of type 1 diabetes, dysregulates Treg cells, and accelerates diabetes in NOD mice. We investigated the relationship between IL-1β production and the response to [RelB.sup.lo] DCs in the prediabetic period. RESEARCH DESIGN AND METHODS--We injected [RelB.sup.lo] DCs subcutaneously into 4- or 14-week-old NOD mice and tracked the incidence of diabetes and effect on Treg cell function. We measured the expression of proinflammatory cytokines by stimulated splenocytes and unstimulated islets from mice of different ages and strains and proliferative and cytokine responses of T effectors to Treg in vitro. RESULTS--Tolerizing [RelB.sup.lo] DCs significantly inhibited diabetes progression when administered to 4-week-old but not 14-week-old mice. IL-1β production by NOD splenocytes and mRNA expression by islets increased from 6 to 16 weeks of age when major histocompatibility complex (MHC)-restricted islet antigen presentation to autoreactive T-cells occurred. IL-1 reduced the capacity of Treg cells to suppress effector cells and promoted their conversion to Th17 cells. [RelB.sup.lo] DCs exacerbated the IL-l-dependent decline in Treg function and promoted Th17 conversion. CONCLUSIONS--IL-1β, generated by islet-autoreactive cells in MHC-susceptible mice, accelerates diabetes by differentiating Th17 at the expense of Treg. Tolerizing DC therapies can regulate islet autoantigen priming and prevent diabetes, but progression past the IL-1β/IL-17 checkpoint signals the need for other strategies.

The metabolic syndrome associated with obesity is characterized by insulin resistance, hyperglycemia, hypertension, and dyslipidemia, reversible by weight loss (1). Studies in obese mice indicate that adipose tissue inflammation, centered [...], OBJECTIVE--Insulin resistance and other features of the metabolic syndrome have been causally linked to adipose tissue macrophages (ATMs) in mice with diet-induced obesity. We aimed to characterize macrophage phenotype and function in human subcutaneous and omental adipose tissue in relation to insulin resistance in obesity. RESEARCH DESIGN AND METHODS--Adipose tissue was obtained from lean and obese women undergoing bariatric surgery. Metabolic markers were measured in fasting serum and ATMs characterized by immunohistology, flow cytometry, and tissue culture studies. RESULTS--ATMs comprised [CD11c.sup.+][CD206.sup.+] cells in "crown" aggregates and solitary [CD11c.sup.+]-[CD206.sup.+] cells at adipocyte junctions. In obese women, [CD11c.sup.+] ATM density was greater in subcutaneous than omental adipose tissue and correlated with markers of insulin resistance. [CD11c.sup.+] ATMs were distinguished by high expression of integrins and antigen presentation molecules; interleukin (IL)-1[beta],-6,-8, and-10; tumor necrosis factor-[alpha]; and CC chemokine ligand-3, indicative of an activated, proinflammatory state. In addition, [CD11c.sup.+] ATMs were enriched for mitochondria and for RNA transcripts encoding mitochondrial, proteasomal, and lysosomal proteins, fatty acid metabolism enzymes, and T-cell chemoattractaats, whereas [Cd11c.sup.-] ATMs were enriched for transcripts involved in tissue maintenance and repair. Tissue culture medium conditioned by [CD11c.sup.+] ATMs, but not [CD11c.sup.-] ATMs or other stromovascular cells, impaired insulin-stimulated glucose uptake by human adipocytes. CONCLUSIONS--These findings identify proinflammatory [CD11c.sup.+] ATMs as markers of insulin resistance in human obesity. In addition, the machinery of [CD11c.sup.+] ATMs indicates they metabolize lipid and may initiate adaptive immune responses.

OBJECTIVE--In a prospective birth cohort study, we followed infants who had a first-degree relative with type 1 diabetes to investigate the relationship between early growth and infant feeding and the [...]

OBJECTIVE--The rising incidence of type 1 diabetes has been attributed to environment, implying a lesser role for genetic susceptibility. However, the rise could be accounted for by either more cases [...]

OBJECTIVE--Latent autoimmune diabetes in adults (LADA) is defined as adult-onset diabetes with circulating islet antibodies but not requiring insulin therapy initially. Diagnosing LADA has treatment implications because of the high [...]

The homeodomain transcription factor Pdx1 is essential for pancreas development. To investigate the role of Pdx1 in the adult pancreas, we employed a mouse model in which transcription of Pdx1 could be reversibly repressed by administration of doxycycline. Repression of Pdx1 in adult mice impaired expression of insulin and glucagon, leading to diabetes within 14 days. Pdx1 repression was associated with increased cell proliferation predominantly in the exocrine pancreas and up-regulation of genes implicated in pancreas regeneration. Following withdrawal of doxycycline and derepression ofPdx1, normoglycemia was restored within 28 days; during this period, Pdx[1.sup.+]/[Ins.sup.+] and [Pdx.sup.+]/[Ins.sup.-] cells were observed in association with the duct epithelia. These findings confirm that Pdx1 is required for β-cell function in the adult pancreas and indicate that in the absence of Pdx1 expression, a regenerative program is initiated with the potential for Pdx1-dependent β-cell neogenesis., Pdx1 a homeodomain transcription factor essential for pancreatic development (1-3). Early in mouse development (embryonic day 8.5), Pdx1 is highly expressed in a region of the posterior foregut endoderm, from [...]

The nature of the T-cell response to antigen is governed by the activation state of the antigen-presenting dendritic cell (DC). Immature or resting DCs have been shown to induce T-cell responses that may protect against the development of autoimmune disease. Effectively harnessing this 'tolerogenic' effect of resting DCs requires that it be disease-specific and that activation of DCs by manipulation ex vivo is avoided. We reasoned that this could be achieved by transferring in vivo partially differentiated myeloid progenitor cells encoding a disease-specific autoantigen. With the aim of preventing autoimmune diabetes, we transferred myeloid progenitor cells encoding proinsulin into NOD mice. Bone marrow (BM) was cultured in granulocyte macrophage colony-stimulating factor (GM-CSF) and transforming growth factor-β1, a cytokine combination that expands myeloid cells but inhibits terminal DC differentiation, to yield [Gr-1.sup.+]/CD[11b.sup.+]/CD[11c.sup.-] myeloid progenitor cells and a minor population of CD[11c.sup.+]/ CD[11b.sup.+]/CD[86.sup.lo] immature DCs. After transfer, [Gr-1.sup.+] myeloid cells acquired the characteristics of resting DCs (CD[11c.sup.+]/MHC class[II.sup.int]/CD[86.sup.lo]/CD[40.sup.lo]). [Gr-1.sup.+] myeloid cells generated from transgenic NOD mice that expressed proinsulin controlled by a major histocompatibility complex (MHC) class II promoter, but not from wild-type NOD mice, transferred into 4-week-old female NOD mice significantly suppressed diabetes development. The transfer of DC progenitors encoding a disease-specific autoantigen is, therefore, an effective immunotherapeutic strategy that could be applied to humans., Antigen-presenting dendritic cells (DCs) determine the functional properties of the T-cells with which they interact. In the absence of activating signals to DCs, such as those mediated through toll-like receptors [...]

OBJECTIVE--Mucosal administration of insulin retards development of autoimmune diabetes in the nonobese diabetic mouse model. We conducted a double-blind crossover study in humans at risk for type 1 diabetes to [...]

Type 1, or insulin-dependent diabetes, is an autoimmune disease that culminates in the destruction of insulin-producing β-cells in the islets of the pancreas. Studies in the nonobese diabetic (NOD) mouse [...]

A workshop on autoreactive T-cell responses in NOD mice was held to optimize autoreactive T-cell detection methodologies. Using different proliferation assay protocols, 1 of the 11 participating laboratories detected spontaneous T-cell responses to GAD(524-543) and insulin(9-23) in their NOD mice. Two other laboratories were able to detect autoreactive responses when using enzyme-linked immunospot assay (ELISPOT) and enzyme-linked immunosorbent assay (ELISA) analysis of cytokines in culture supernatants, suggesting that these assays provided greater sensitivity. To address the divergent findings, a follow-up mini-workshop tested NOD mice from four different colonies side-by-side for T-cell proliferative responses to an expanded panel of autoantigens, using the protocol that had enabled detection of responses in the 1st International NOD Mouse T-Cell Workshop. Under these assay conditions, 16 of 16 NOD mice displayed proliferative responses to whole GAD65, 13 of 16 to GAD(524-543), 9 of 16 to GAD(217-236), 7 of 16 to insulin(9-23), and 5 of 16 to HSP277. Thus, spontaneous proliferative T-cell responses can be consistently detected to some β-cell autoantigens and peptides thereof. Overall, the results suggest that more sensitive assays (e.g., ELISPOT, ELISA analysis of cytokines in supernatants, or tetramer staining) may be preferred for the detection of autoreactive T-cells., The results of the recent Human T-Cell Workshops demonstrated that significant problems exist in documenting T-cell responses to β-cell autoantigens in humans (1). With this in mind, it was thought [...]

Administration of antigens via mucosal routes, such as orally or intranasally, can induce specific immunological tolerance and has been used as a rational basis for the treatment of autoimmune diseases, [...]

Type 1 diabetes mellitus, a chronic autoimmune disease, can be diagnosed in a preclinical stage. Autoantibodies to glutamic acid decarboxylase and tyrosine phosphatase IA2 were reported superior to islet cell antibodies as a screening tool for preclinical diagnosis of type 1 diabetes.

Specific HLA DRbeta1 antigens that are produced in 90% of patients with rheumatoid arthritis (RA) do not appear to be involved in the development of the disease. Because these antigens are shared by so many patients, they are called shared epitopes. Researchers took blood samples from 20 patients with recent onset RA and 20 healthy volunteers and measured T cell reactivity to these shared epitopes. RA patients did not have significantly greater T cell reactivity to the shared epitopes than the healthy group.

IDDM in humans and in nonobese diabetic (NOD) mice is a T-cell-dependent autoimmune disease in which the β-cells of the pancreatic islets are destroyed. Several putative β-cell autoantigens have been [...]

Glutamic acid decarboxylase antibodies (GADAbs) are being increasingly used in clinical and research programs for the prediction and classification of insulin-dependent diabetes mellitus (IDDM). A number of different assay formats [...]

Target antigens defined by autoantibodies in IDDM include insulin, a putative glycolipid that reacts with islet cell antibodies, and a 64,000-[M.sub.r] protein recently identified as glutamic acid decarboxylase. In addition, [...]

To detect serum antibodies to GAD in subjects with IDDM, three recombinant mBGAD 67 peptides encompassing the full-length protein were used in an ELISA. In this study 7 of 9 [...]

Research has demonstrated abnormalities in the hormonal balance of the hypothalamic-pituitary adrenal (HPA) axis in the low-weight phase of anorexia nervosa and has linked HPA-axis hyperactivity and depression. To further investigate relationships between weight change, HPA-axis function, and depression, 20 hospitalized female anorexic patients (average age 21.1 years) were weighed weekly, and given weekly dexamethasone suppression tests (DSTs); dexamethasone is an anti-inflammation steroid. The DST determines the ability of dexamethasone to suppress HPA-axis production of cortisol (an adrenal hormone that plays a role in fat and water metabolism) for 24 hours. Anorexics tend toward high cortisol production rates, and tend not to suppress cortisol production after the DST. Eighteen female volunteers (average age of 27 years), served as study controls, and also had weekly DSTs. At initial DST, all controls were found to be cortisol suppressors, while only half of the anorexic patients were. No relationship was found between severity of weight loss and HPA-axis dysfunction. Weight gain had no effect on normalization of the DST response. Of the 10 anorexic patients who were initially non-suppressors, seven became suppressors before hospital discharge. Seventeen of the 20 anorexic patients scored in the depressed range on a depression rating scale; 10 of the 17 scored in the severely depressed range. However, no relationships were found between depression and suppressor status, or between depression and weight status. There was a significant inverse relationship found between pre- and post-DST plasma cortisol and dexamethasone concentrations. Overall results indicate that more than one mechanism is responsible for an abnormal DST in anorexia and that further exploration is required. (Consumer Summary produced by Reliance Medical Information, Inc.)

Loss of heterochromatin has been proposed as a universal mechanism of aging across different species and cell types. However, a comprehensive analysis of hematopoietic changes caused by heterochromatin loss is lacking. Moreover, there is conflict in the literature around the role of the major heterochromatic histone methyltransferase Suv39h1 in the aging process. Here, we use individual and dual deletion of Suv39h1 and Suv39h2 enzymes to examine the causal role of heterochromatin loss in hematopoietic cell development. Loss of neither Suv39h1 nor Suv39h2 individually had any effect on hematopoietic stem cell function or the development of mature lymphoid or myeloid lineages. However, deletion of both enzymes resulted in characteristic changes associated with aging such as reduced hematopoietic stem cell function, thymic involution and decreased lymphoid output with a skewing toward myeloid development, and increased memory T cells at the expense of naive T cells. These cellular changes were accompanied by molecular changes consistent with aging, including alterations in nuclear shape and increased nucleolar size. Together, our results indicate that the hematopoietic system has a remarkable tolerance for major disruptions in chromatin structure and reveal a role for Suv39h2 in depositing sufficient H3K9me3 to protect the entire hematopoietic system from changes associated with premature aging.

Pancreatic islet autoimmunity leading to type I diabetes could be triggered by viruses in genetically susceptible individuals. Rotavirus (RV), the most common cause of childhood gastroenteritis, contains peptide sequences highly [...]

There is considerable debate as to whether beta cell destruction occurs chronically over years or is a more acute process preceding the onset of type 1 diabetes. A previous study [...]

The hypothesis that early exposure to cow's milk or lack of breast-feeding predisposes to type 1 diabetes remains controversial. We aimed to determine prospectively the relationship of, first, duration of [...]

The Real Debate Is About Mucosal Immune Function The hypothesis that early exposure of the infant to cow's milk (or lack of breast-feeding) predisposes the child to type 1 diabetes [...]

Antigen-specific, mucosa-mediated immunotherapy for the prevention of type 1 diabetes is based on studies in the NOD mouse in which oral or aerosol insulin or intranasal (pro)insulin or GAD peptides [...]

Rotavirus (RV) causes winter epidemics of diarrhoea and is ubiquitous in infants. The VP7 protein of RV contains sequences with high similarity to T-cell epitopes in tyrosine phosphatase IA-2 (aa [...]

Insulin aerosol reduces diabetes incidence in NOD mice and induces CD8 [Gamma][Delta] T cells that block adoptive transfer of diabetes by T cells. These regulatory T cells express CD8 [Alpha][Alpha] [...]

Soluble CD52 is a small glycoprotein that suppresses T-cell activation, but its effect on innate immune cell function is unknown. Here we demonstrate that soluble CD52 inhibits Toll-like receptor and tumor necrosis factor receptor signaling to limit activation of NF-?B and thereby suppress the production of inflammatory cytokines by macrophages, monocytes and dendritic cells. At higher concentrations, soluble CD52 depletes the short-lived pro-survival protein MCL-1, contributing to activation of the BH3-only proteins BAX and BAK to cause intrinsic apoptotic cell death. In vivo, administration of soluble CD52 suppresses lipopolysaccharide (LPS)-induced cytokine secretion and other features of endotoxic shock, whereas genetic deletion of CD52 exacerbates LPS responses. Thus, soluble CD52 exhibits broad immune suppressive effects that signify its potential as an immunotherapeutic agent.

Supplemental digital content is available in the text.

The gut microbiota can influence immune-cell function by the production of short-chain fatty acids. Mackay and colleagues show that diets enriched for acetate and butyrate protect non-obese diabetic mice from insulitis and diabetes progression.

Hyperexpression of major histocompatibility complex (MHC) molecules by islet cells is a prominent, early feature of islet pathology in insulin-dependent diabetes mellitus and concomitant with β-cell failure after exposure of [...]

Differentiation of naïve CD4+ T cells into effector (Th1, Th2, and Th17) and induced regulatory (iTreg) T cells requires lineage-specifying transcription factors and epigenetic modifications that allow appropriate repression or activation of gene transcription. The epigenetic silencing of cytokine genes is associated with the repressive H3K27 trimethylation mark, mediated by the Ezh2 or Ezh1 methyltransferase components of the polycomb repressive complex 2 (PRC2). Here we show that silencing of the Ifng, Gata3, and Il10 loci in naïve CD4+ T cells is dependent on Ezh2. Naïve CD4+ T cells lacking Ezh2 were epigenetically primed for overproduction of IFN-γ in Th2 and iTreg and IL-10 in Th2 cells. In addition, deficiency of Ezh2 accelerated effector Th cell death via death receptor–mediated extrinsic and intrinsic apoptotic pathways, confirmed in vivo for Ezh2-null IFN-γ–producing CD4+ and CD8+ T cells responding to Listeria monocytogenes infection. These findings demonstrate the key role of PRC2/Ezh2 in differentiation and survival of peripheral T cells and reveal potential immunotherapeutic targets.

Extracellular factors that regulate the growth and differentiation of cell lineages in the pancreatic primordia are poorly understood. Identification of these factors for pancreatic islet Β-cells could open new avenues [...]

Regulatory T cells (Treg) prevent the emergence of autoimmune disease. Prototypic natural Treg (nTreg) can be reliably identified by demethylation at the Forkhead-box P3 (FOXP3) locus. To explore the methylation landscape of nTreg, we analyzed genome-wide methylation in human naive nTreg (rTreg) and conventional naive CD4+ T cells (Naive). We detected 2315 differentially methylated cytosine–guanosine dinucleotides (CpGs) between these 2 cell types, many of which clustered into 127 regions of differential methylation (RDMs). Activation changed the methylation status of 466 CpGs and 18 RDMs in Naive but did not alter DNA methylation in rTreg. Gene-set testing of the 127 RDMs showed that promoter methylation and gene expression were reciprocally related. RDMs were enriched for putative FOXP3-binding motifs. Moreover, CpGs within known FOXP3-binding regions in the genome were hypomethylated. In support of the view that methylation limits access of FOXP3 to its DNA targets, we showed that increased expression of the immune suppressive receptor T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT), which delineated Treg from activated effector T cells, was associated with hypomethylation and FOXP3 binding at the TIGIT locus. Differential methylation analysis provides insight into previously undefined human Treg signature genes and their mode of regulation.

Vaccination against self-antigens to avert pathological immunity to self - ‘negative vaccination’ - is the Holy Grail of autoimmune disease therapy. This approach depends on deletion or inactivation of pathogenic T cells, or induction of protective, ‘regulatory’ T cells. While effective in inbred rodent models, it is yet to be translated to humans. Reasons for this include its application only in end-stage disease, ignorance about antigen form, route of delivery and dose-schedule required for a bio-response, lack of meaningful and measurable bio-response markers, co-activation of pathogenic immunity and genetic heterogeneity.

Detection of human Ag-specific T cells is limited by sensitivity and blood requirements. As dendritic cells (DCs) can potently stimulate T cells, we hypothesized that their induction in PBMCs in situ could link Ag processing and presentation to Ag-specific T-cell activation. To this end, unfractionated PBMCs (fresh or frozen) or whole blood were incubated for 48 hours with protein or peptide Ag together with different DC-activating agents to rapidly and sequentially induce, pulse, and mature DCs. DC activation was therefore lined up with Ag recognition by neighboring T cells, thus telescoping the sequential steps of T-cell activation. Efficient processing of protein Ags made prior knowledge of epitopes and HLA restrictions dispensable. While reducing stimulation time, manipulation and blood requirements, in situ DC induction specifically amplified Ag-specific T-cell responses (cytokine secretion, proliferation, CD137/CD154 up-regulation, and binding of peptide-HLA multimers). IL-1β, although released by DCs, was also secreted in an Ag-specific fashion, thus providing an indirect biomarker of T-cell responses. These accelerated cocultured DC (acDC) assays offered a sensitive means with which to evaluate T-cell responses to viral and melanoma Ag vaccination, and may therefore find application for immune monitoring in viral, tumor, autoimmune, and transplantation settings.

The progressive increase in the incidence of both type 1 diabetes mellitus (T1DM) and T2DM, which is associated with changing environmental conditions, highlights overlapping clinical and pathogenetic features of these diabetes stereotypes. The article proposes that the common thread is a proinflammatory environment that activates innate immunological and inflammatory pathways, which lead to β-cell dysfunction in T2DM, insulin resistance in both T1DM and T2DM, and enhanced adaptive immunity that kills β cells in T1DM.

Type 1 diabetes (T1D) is an autoimmune disease in which genes and environment contribute to cell-mediated immune destruction of insulin-producing ? cells in the islets of the pancreas. An understanding of pathogenetic mechanisms paves the way for vaccination strategies to prevent T1D. Primary prevention by traditional ‘positive’ vaccination awaits clear evidence of a the role for infectious agents in triggering the disease process. Following initiation of disease, at-risk individuals with underlying islet inflammation can be identified by the presence of circulating autoantibodies to islet antigens. This pre-clinical phase of T1D, before insulin deficiency leads to symptoms of hyperglycemia, provides a window for secondary prevention. The therapeutic Holy Grail in autoimmune disease is ‘negative’ vaccination against autoantigens that drive immune-mediated pathology, to induce disease-specific immune tolerance. This can be achieved by administering autoantigen via a ‘tolerogenic’ (e.g. mucosal) route, cell (e.g. resting dendritic cell), mode (e.g. with blockade of co-stimulation molecules) or form (as an ‘altered peptide ligand’). These strategies to induce immune tolerance are effective in rodent models of autoimmune disease, but in application to humans the results have so far been disappointing. This review discusses the prospects of vaccination to prevent T1D, focusing on autoantigen-specific mucosal tolerance.

A dendritic cell (DC) imbalance with a marked deficiency in CD4−8+ DC occurs in non-obese diabetic (NOD) mice, a model of human autoimmune diabetes mellitus. Using a NOD congenic mouse strain, we find that this CD4−8+ DC deficiency is associated with a gene segment on chromosome 4, which also encompasses non-MHC diabetes susceptibility loci. Treatment of NOD mice with fms-like tyrosine kinase 3 ligand (FL) enhances the level of CD4−8+ DC, temporarily reversing the DC subtype imbalance. At the same time, fms-like tryosine kinase 3 ligand treatment blocks early stages of the diabetogenic process and with appropriately timed administration can completely prevent diabetes development. This points to a possible clinical use of FL to prevent autoimmune disease.

T lymphocytes (pivotal in many inflammatory pathologies) are targets for glucocorticoid hormone (GC). How TCR-mediated activation and GC signaling via glucocorticoid receptor (GR) impact on T-cell fates is not fully defined. We delineated here the expression of a recently identified glucocorticoid-induced TNF receptor (GITR) induced by GC and by TCR-mediated T-cell activation in GC receptor (GR)-deficient mice (GR−/−). We also compared the action of GC on GITR+ and GITR− T cells by monitoring apoptosis, proliferation and cytokine production stimulated by anti-CD3 antibody. By using GR−/− mice, we observed that the development of GITR+ T cells (both in thymus and periphery) is not dependent upon GR signaling. This contradicts the implication of GITR's name reflecting GC induction. TCR-mediated T-cell activation induced GITR expression in both GR+/+ and GR−/− cells. Somewhat unexpectedly, there was very modest GITR upregulation on GR+/+ T cells by a range of GC doses (10−8 to 10−6 M). Constitutive expression of GITR by a subset of CD4+ cells did not significantly render them resistant to GC-induced cell death. However, TCR-induced GITR upregulation on GR+/+ T cells was correlated with resistance to GC-mediated apoptosis suggesting that GITR, in conjunction with other (as yet unidentified) TCR-induced factors, protects T cells from apoptosis. Thus, even though GC is a potent inducer of apoptosis of T cells, activated T cells are resistant to GC-mediated killing. Meanwhile, although GC suppressed anti-CD3-induced cytokine production, cell proliferation was unaffected by GC in GR+/+ mice. GR deficiency has no effect on anti-CD3-induced cytokine production and proliferation. Our findings also have implications for GC treatment in that it would be more difficult to abrogate an ongoing T-cell mediated inflammatory response than to prevent its induction.

The Melbourne Prediabetes Family Study, a prospective study of first-degree relatives of people with type 1 diabetes (T1D), provided an opportunity to examine late-onset autoimmune diabetes within the context of a family history of T1D. We compared genetic, immunologic, and clinical features in relatives of people with T1D, who developed early- versus late-onset diabetes.

Cell lineage development is a finely tuned process of proliferation and differentiation, survival and apoptosis, that is regulated by numerous extracellular signals. Here we review some of the extracellular signals—including insoluble cell-cell and extracellular matrix-cell interactions, as well as soluble factors—that appear critical for pancreatic β-cell development. Knowledge of how these signals control the development of pancreatic endocrine stem/precursor cells into fully functional insulin-secreting βcells is a platform for the restoration of β-cell function and the cure therapy of type 1 diabetes.

ABSTRACTRotavirus infection in children at risk of developing type 1 diabetes has been temporally associated with development of pancreatic islet autoantibodies. In this study, nonobese diabetic mice were shown to be susceptible to rhesus rotavirus infection and pancreatic islets from nonobese diabetic mice, nonobese diabetes-resistant mice, fetal pigs, and macaque monkeys supported various degrees of rotavirus growth. Human rotaviruses replicated in monkey islets only. This islet susceptibility shows that rotavirus infection of the pancreas in vivo might be possible.

Pancreatic islet xenotransplantation has been advocated as a way of overcoming the shortage of human donor tissue for the treatment of type 1 diabetes. However, the potent immune response against xenografts is a major barrier to their use. We show that a short course of the anti‐CD45RB antibody, MB23G2, prolongs survival of fetal pig pancreas grafts in mice. To investigate this effect further we used an i.p. xenograft model in which both donor pig cells and host inflammatory cells can be expediently recovered and analyzed. Graft prolongation was associated with reduced T cell and macrophage infiltration, and reduced production of both Th1 and Th2 cytokines at the graft site. Graft survival was further increased and T cell infiltration further reduced by combining anti‐CD45RB antibody with co‐stimulation blockade. The primary effect of anti‐CD45RB antibody may be on CD4 T cells, in keeping with the marked reduction in T cell cytokine production in both spleen and graft sites. This concurs with previous studies in allogeneic models that indicate that this antibody perturbs T cell responses by modifying signaling via the TCR. In addition, anti‐CD45RB treatment led to reduced expression of LFA‐1 and CD62 ligand (CD62L) on CD4 T cells, independent of antigenic challenge. LFA‐1 may enhance co‐stimulation, and both LFA‐1 and CD62L are involved in T cell trafficking. Their reduced expression provides an explanation why the T cell pool is reduced in lymph nodes. We conclude that modulation of inflammation against xenografts by anti‐CD45RB antibody is due to effects on both T cell priming and trafficking.

The innate immune system existed prior to the emergence of adaptive immunity in sharks and higher vertebrates. Homologues of many mammalian innate immune‐system elements such as the toll‐like receptors exist in species as distant as Drosophila. Selective pressure has led to the development of highly conserved, soluble, and cell‐surface receptors that recognize functionally essential molecules shared by microbial pathogens. It is thought that molecular patterns that exquisitely distinguish pathogenic cells from mammalian cells are recognized. Therefore, it would seem unlikely that innate immune‐system elements should recognize mammalian tissues. However, there is increasing evidence to suggest that this is the case and that innate immunity promotes rejection of transplanted mammalian tissues, particularly those from other species (xenografts). Evidence for innate recognition of mammalian grafts, the nature of this recognition, and the bi‐directional interactions between innate and adaptive immunity that contribute to graft rejection are discussed in this review, with the emphasis on nonvascular xenografts.