Th1 to Th2 cytokine shifts in nonobese diabetic mice: sometimes an outcome, rather than the cause, of diabetes resistance elicited by immunostimulation

Numerous immunostimulatory protocols inhibit the development of T cell-mediated autoimmune insulin-dependent diabetes mellitus (IDDM) in the nonobese diabetic (NOD) mouse model. Many of these protocols, including treatment with the nonspecific immunostimulatory agents CFA or bacillus Calmette-Guérin (BCG) vaccine, have been reported to mediate protection by skewing the pattern of cytokines produced by pancreatic beta-cell autoreactive T cells from a Th1 (IFN-gamma) to a Th2 (IL-4 and IL-10) profile. However, most of these studies have documented associations between such cytokine shifts and disease protection rather than a cause/effect relationship. To partially address this issue we produced NOD mice genetically deficient in IFN-gamma, IL-4, or IL-10. Elimination of any of these cytokines did not significantly alter the rate of spontaneous IDDM development. Additional experiments using these mice confirmed that CFA- or BCG-elicited diabetes protection is associated with a decreased IFN-gamma to IL-4 mRNA ratio within T cell-infiltrated pancreatic islets, but this is a secondary consequence rather than the cause of disease resistance. Unexpectedly, we also found that the ability of BCG and, to a lesser extent, CFA to inhibit IDDM development in standard NOD mice is actually dependent upon the presence of the Th1 cytokine, IFN-gamma. Collectively, our studies demonstrate that while Th1 and Th2 cytokine shifts may occur among beta-cell autoreactive T cells of NOD mice protected from overt IDDM by various immunomodulatory therapies, it cannot automatically be assumed that this is the cause of their disease resistance.     

IgG1 subclass dominates autoimmune response to tyrosine phosphatase-like molecule IA-2 in Chinese type 1 diabetes patients.

BACKGROUND AND AIMS: Islet autoantibodies are known markers for type 1 diabetes with an immune-mediated basis; their isotype or subclass profiles may also provide clues to changes in immune response during disease or after intervention. For ICAs and GADab, the IgG1 subclass consistently dominates in recent-onset disease. The aims of our study were to determine the isotype patterns for IA-2ab in Asian Chinese patients with autoimmune diabetes. MATERIALS AND METHODS: From an initial screening of over 400 diabetes patients, 40 subjects (mean age 22.2 +/- 15.8 years) with IA-2ab were enrolled for this study. IA-2ab was detected by radioimmunoassay of [35S]-labelled recombinant human IA-2 ic(605 - 979). Of them, 31 (median age 15 years, range 2 - 57 years; 16 children) had clinical type 1 diabetes (that is, they required insulin at onset or within 1 year) with the majority having been recently diagnosed (< 1 year). The other 9 patients had clinical type 2 diabetes phenotype. RESULTS: IA-2ab IgG subclasses determined with monospecific secondary antibodies showed that both type 1 diabetic adults and children had similarly non-restricted isotype patterns with a strong presence of IgG1-IA-2ab. The rank order was IgG1 > 3 > 2 > 4; 15 subjects had detectable IgG4-IA-2ab. Clonality of immune response determined with kappa/lambda chain-specific antibodies also showed a non-restricted pattern. Patients aged 38.2 +/- 15.2 years with type 2 diabetes had broad patterns of isotypes - IgG1/3 was detected more frequently (n = 8) than IgG2/4 (n = 5). Of three patients on insulin treatment, one was also positive for GADab. The remaining 6 patients were on oral hypoglycaemic treatment. IA-2ab in type 2 diabetes showed a low titre compared to type 1 diabetes. CONCLUSIONS: Isotype responses to IA-2 had a strong IgG1 presence, similar to ICAs and GADab. With IgG3 subclass representation, a predominant Th1 milieu in the systemic environment is likely. There is no suggestion of differences in immune response to IA-2 between adults and children with type 1 diabetes.     

Engineering and expression of the intracellular domain of insulinoma-associated tyrosine phosphatase (IA-2ic), a type 1 diabetes autoantigen,in plants

We have produced the recombinant intracellular domain of human IA-2 (IA-2ic), a diabetes-associated autoantigen, in plants. This was achieved by transient expression using agroinfiltration of Nicotiana benthamiana plants. The resulting plant-derived IA-2ic had the expected size, reacted with polyclonal and monoclonal antibodies specific to human IA-2ic and competitively inhibited radiolabeled IA-2ic in an immunoprecipitation assay. The expression level of recombinant IA-2ic was estimated to be 0.5% of the total soluble protein (TSP). Transient expression in plants has the potential to produce a large amount of human IA-2ic protein at low cost in a short period of time.     

Manipulation of CD98 resolves type 1 diabetes in nonobese diabetic mice

The interplay of CD4(+) and CD8(+) T cells targeting autoantigens is responsible for the progression of a number of autoimmune diseases, including type 1 diabetes mellitus (T1D). Understanding the molecular mechanisms that regulate T cell activation is crucial for designing effective therapies for autoimmune diseases. We probed a panel of Abs with T cell-modulating activity and identified a mAb specific for the H chain of CD98 (CD98hc) that was able to suppress T cell proliferation. The anti-CD98hc mAb also inhibited Ag-specific proliferation and the acquisition of effector function by CD4(+) and CD8(+) T cells in vitro and in vivo. Injection of the anti-CD98hc mAb completely prevented the onset of cyclophosphamide-induced diabetes in NOD mice. Treatment of diabetic NOD mice with anti-CD98hc reversed the diabetic state to normal levels, coincident with decreased proliferation of CD4(+) T cells. Furthermore, treatment of diabetic NOD mice with CD98hc small interfering RNA resolved T1D. These data indicate that strategies targeting CD98hc might have clinical application for treating T1D and other T cell-mediated autoimmune diseases.     

A Th1-recognized peptide P277, when tandemly repeated, enhances a Th2 immune response toward effective vaccines against autoimmune diabetes in nonobese diabetic mice

Subunit immunogens containing tandemly repeated copies of T and B cell epitopes have been shown to be more immunogenic than the respective immunogen containing only a single copy of the sequence. To investigate whether the increased copies of the Th2-activated peptide sequence will enhance the Th2-like immune response, we compared the cytokine secreted in mice that inoculated with two immunogens containing one or six tandemly repeated copies of a Th2-activated peptide sequence P277. Immunization of mice with a 6xP277 fusion protein elicited much higher levels of Th2-type cytokines and lower Th1-type cytokines than with a fusion protein with one P277 peptide. The data of tandemly repeated peptide P277 potentiate the anti-inflammatory in NOD mice, most likely associated with a Th1 to Th2 cytokine shift specific for the autoimmune T cells, which suggested that application of multiple tandem repeats of a Th2-activated epitope is an efficient method to enhance the anti-inflammatory immune response by shifting the immune response from Th1-like to Th2-like. The subunit immunogens containing tandemly repeated copies of peptide P277 might be effective vaccines against autoimmune diabetes in NOD mice.     

Pancreas-infiltrating Th1 cells and diabetes develop in IL-12-deficient nonobese diabetic mice.

IL-12 and IL-12 antagonist administration to nonobese diabetic (NOD) mice accelerates and prevents insulin-dependent diabetes mellitus (IDDM), respectively. To further define the role of endogenous IL-12 in the development of diabetogenic Th1 cells, IL-12-deficient NOD mice were generated and analyzed. Th1 responses to exogenous Ags were reduced by approximately 80% in draining lymph nodes of these mice, and addition of IL-12, but not IL-18, restored Th1 development in vitro, indicating a nonredundant role of IL-12. Moreover, spontaneous Th1 responses to a self Ag, the tyrosine phosphatase-like IA-2, were undetectable in lymphoid organs from IL-12-deficient, in contrast to wild-type, NOD mice. Nevertheless, wild-type and IL-12-deficient NOD mice developed similar insulitis and IDDM. Both in wild-type and IL-12-deficient NOD mice, approximately 20% of pancreas-infiltrating CD4+ T cells produced IFN-gamma, whereas very few produced IL-10 or IL-4, indicating that IDDM was associated with a type 1 T cell infiltrate in the target organ. T cell recruitment in the pancreas seemed favored in IL-12-deficient NOD mice, as revealed by increased P-selectin ligand expression on pancreas-infiltrating T cells, and this could, at least in part, compensate for the defective Th1 cell pool recruitable from peripheral lymphoid organs. Residual Th1 cells could also accumulate in the pancreas of IL-12-deficient NOD mice because Th2 cells were not induced, in contrast to wild-type NOD mice treated with an IL-12 antagonist. Thus, a regulatory pathway seems necessary to counteract the pathogenic Th1 cells that develop in the absence of IL-12 in a spontaneous chronic progressive autoimmune disease under polygenic control, such as IDDM.     

Loss of invariant chain protects nonobese diabetic mice against type 1 diabetes

The invariant (Ii) chain acts as an essential chaperone to promote MHC class II surface expression, Ag presentation, and selection of CD4(+) T cells. We have examined its role in the development of type 1 diabetes in NOD mice and show that Ii chain-deficient NOD mice fail to develop type 1 diabetes. Surprisingly, Ii chain functional loss fails to disrupt in vitro presentation of islet Ags, in the context of NOD I-A(g7) molecules. Moreover, pathogenic effector cells could be shown to be present in Ii chain-deficient NOD mice because they were able to transfer diabetes to NOD.scid recipients. The ability of these cells to transfer diabetes was markedly enhanced by depletion of CD25 cells coupled with in vivo anti-CD25 treatment of recipient mice. The numbers of CD4(+)CD25(+)Foxp3(+) T cells in thymus and periphery of Ii chain-deficient NOD mice were similar to those found in normal NOD mice, in contrast to conventional CD4(+) T cells whose numbers were reduced. This suggests that regulatory T cells are unaffected in their selection and survival by the absence of Ii chain and that an alteration in the balance of effector to regulatory T cells contributes to diabetes prevention.     

Lipopolysaccharide-activated B cells down-regulate Th1 immunity and prevent autoimmune diabetes in nonobese diabetic mice.

B cells can serve dual roles in modulating T cell immunity through their potent capacity to present Ag and induce regulatory tolerance. Although B cells are necessary components for the initiation of spontaneous T cell autoimmunity to beta cell Ags in nonobese diabetic (NOD) mice, the role of activated B cells in the autoimmune process is poorly understood. In this study, we show that LPS-activated B cells, but not control B cells, express Fas ligand and secrete TGF-beta. Coincubation of diabetogenic T cells with activated B cells in vitro leads to the apoptosis of both T and B lymphocytes. Transfusion of activated B cells, but not control B cells, into prediabetic NOD mice inhibited spontaneous Th1 autoimmunity, but did not promote Th2 responses to beta cell autoantigens. Furthermore, this treatment induced mononuclear cell apoptosis predominantly in the spleen and temporarily impaired the activity of APCs. Cotransfer of activated B cells with diabetogenic splenic T cells prevented the adoptive transfer of type I diabetes mellitus (T1DM) to NOD/scid mice. Importantly, whereas 90% of NOD mice treated with control B cells developed T1DM within 27 wk, <20% of the NOD mice treated with activated B cells became hyperglycemic up to 1 year of age. Our data suggest that activated B cells can down-regulate pathogenic Th1 immunity through triggering the apoptosis of Th1 cells and/or inhibition of APC activity by the secretion of TGF-beta. These findings provide new insights into T-B cell interactions and may aid in the design of new therapies for human T1DM.     

Molecular genetic analysis of the Idd4 locus implicates the IFN response in type 1 diabetes susceptibility in nonobese diabetic mice

High-resolution mapping and identification of the genes responsible for type 1 diabetes (T1D) has proved difficult because of the multigenic etiology and low penetrance of the disease phenotype in linkage studies. Mouse congenic strains have been useful in refining Idd susceptibility loci in the NOD mouse model and providing a framework for identification of genes underlying complex autoimmune syndromes. Previously, we used NOD and a nonobese diabetes-resistant strain to map the susceptibility to T1D to the Idd4 locus on chromosome 11. Here, we report high-resolution mapping of this locus to 1.4 megabases. The NOD Idd4 locus was fully sequenced, permitting a detailed comparison with C57BL/6 and DBA/2J strains, the progenitors of T1D resistance alleles found in the nonobese diabetes-resistant strain. Gene expression arrays and quantitative real-time PCR were used to prioritize Idd4 candidate genes by comparing macrophages/dendritic cells from congenic strains where allelic variation was confined to the Idd4 interval. The differentially expressed genes either were mapped to Idd4 or were components of the IFN response pathway regulated in trans by Idd4. Reflecting central roles of Idd4 genes in Ag presentation, arachidonic acid metabolism and inflammation, phagocytosis, and lymphocyte trafficking, our combined analyses identified Alox15, Alox12e, Psmb6, Pld2, and Cxcl16 as excellent candidate genes for the effects of the Idd4 locus.     

Salmonella typhimurium infection in nonobese diabetic mice generates immunomodulatory dendritic cells able to prevent type 1 diabetes

Infection, commencing across a wide age range, with a live, attenuated strain of Salmonella typhimurium, will halt the development of type 1 diabetes in the NOD mouse. The protective mechanism appears to involve the regulation of autoreactive T cells in a manner associated with long lasting changes in the innate immune compartment of these mice. We show in this study that autoreactive T cell priming and trafficking are altered in mice that have been infected previously by S. typhimurium. These changes are associated with sustained alterations in patterns of chemokine expression. We find that small numbers of dendritic cells from mice that have been previously infected with, but cleared all trace of a S. typhimurium infection are able to prevent the development of diabetes in the highly synchronized and aggressive cyclophosphamide-induced model. The effects we observe on autoreactive T cell trafficking are recapitulated by the immunomodulatory dendritic cell transfers in the cyclophosphamide model.     

Testing the role of P2X7 receptors in the development of type 1 diabetes in nonobese diabetic mice

Although P2rx7 has been proposed as a type 1 diabetes (T1D) susceptibility gene in NOD mice, its potential pathogenic role has not been directly determined. To test this possibility, we generated a new NOD stock deficient in P2X(7) receptors. T1D development was not altered by P2X(7) ablation. Previous studies found CD38 knockout (KO) NOD mice developed accelerated T1D partly because of a loss of CD4(+) invariant NKT (iNKT) cells and Foxp3(+) regulatory T cells (Tregs). These immunoregulatory T cell populations are highly sensitive to NAD-induced cell death activated by ADP ribosyltransferase-2 (ART2)-mediated ADP ribosylation of P2X(7) receptors. Therefore, we asked whether T1D acceleration was suppressed in a double-KO NOD stock lacking both P2X(7) and CD38 by rescuing CD4(+) iNKT cells and Tregs from NAD-induced cell death. We demonstrated that P2X(7) was required for T1D acceleration induced by CD38 deficiency. The CD38 KO-induced defects in homeostasis of CD4(+) iNKT cells and Tregs were corrected by coablation of P2X(7). T1D acceleration in CD38-deficient NOD mice also requires ART2 expression. If increased ADP ribosylation of P2X(7) in CD38-deficient NOD mice underlies disease acceleration, then a comparable T1D incidence should be induced by coablation of both CD38 and ART2, or CD38 and P2X(7). However, a previously established NOD stock deficient in both CD38 and ART2 expression is T1D resistant. This study demonstrated the presence of a T1D resistance gene closely linked to the ablated Cd38 allele in the previously reported NOD stock also lacking ART2, but not in the newly generated CD38/P2X(7) double-KO line.     

A glutamic acid decarboxylase 65-specific Th2 cell clone immunoregulates autoimmune diabetes in nonobese diabetic mice

Several studies have provided indirect evidence in support of a role for beta cell-specific Th2 cells in regulating insulin-dependent diabetes (IDDM). Whether a homogeneous population of Th2 cells having a defined beta cell Ag specificity can prevent or suppress autoimmune diabetes is still unclear. In fact, recent studies have demonstrated that beta cell-specific Th2 cell clones can induce IDDM. In this study we have established Th cell clones specific for glutamic acid decarboxylase 65 (GAD65), a known beta cell autoantigen, from young unimmunized nonobese diabetic (NOD) mice. Adoptive transfer of a GAD65-specific Th2 cell clone (characterized by the secretion of IL-4, IL-5, and IL-10, but not IFN-gamma or TGF-beta) into 2- or 12-wk-old NOD female recipients prevented the progression of insulitis and subsequent development of overt IDDM. This prevention was marked by the establishment of a Th2-like cytokine profile in response to a panel of beta cell autoantigens in cultures established from the spleen and pancreatic lymph nodes of recipient mice. The immunoregulatory function of a given Th cell clone was dependent on the relative levels of IFN-gamma vs IL-4 and IL-10 secreted. These results provide direct evidence that beta cell-specific Th2 cells can indeed prevent and suppress autoimmune diabetes in NOD mice.     

IFN beta accelerates autoimmune type 1 diabetes in nonobese diabetic mice and breaks the tolerance to beta cells in nondiabetes-prone mice

Genetic and environmental factors are decisive in the etiology of type 1 diabetes. Viruses have been proposed as a triggering environmental event and some evidences have been reported: type I IFNs exist in the pancreata of diabetic patients and transgenic mice expressing these cytokines in beta cells develop diabetes. To determine the role of IFNbeta in diabetes, we studied transgenic mice expressing human IFNbeta in the beta cells. Autoimmune features were found: MHC class I islet hyperexpression, T and B cells infiltrating the islets and transfer of the disease by lymphocytes. Moreover, the expression of beta(2)-microglobulin, preproinsulin, and glucagon in the thymus was not altered by IFNbeta, thus suggesting that the disease is caused by a local effect of IFNbeta, strong enough to break the peripheral tolerance to beta cells. This is the first report of the generation of NOD (a model of spontaneous autoimmune diabetes) and nonobese-resistant (its homologous resistant) transgenic mice expressing a type I IFN in the islets: transgenic NOD and nonobese-resistant mice developed accelerated autoimmune diabetes with a high incidence of the disease. These results indicate that the antiviral cytokine IFNbeta breaks peripheral tolerance to beta cells, influences the insulitis progression and contributes to autoimmunity in diabetes and nondiabetes- prone mice.     

IL-18 inhibits diabetes development in nonobese diabetic mice by counterregulation of Th1-dependent destructive insulitis.

The development of type 1 diabetes in animal models is T cell and macrophage dependent. Islet inflammation begins as peripheral benign Th2 type insulitis and progresses to destructive Th1 type insulitis, which is driven by the innate immune system via secretion of IL-12 and IL-18. We now report that daily application of IL-18 to diabetes-prone female nonobese diabetic mice, starting at 10 wk of age, suppresses diabetes development (p < 0.001, 65% in sham-treated animals vs 33% in IL-18-treated animals by 140 days of age). In IL-18-treated animals, we detected significantly lower intraislet infiltration (p < 0.05) and concomitantly an impaired progression from Th2 insulitis to Th1-dependent insulitis, as evidenced from IFN-gamma and IL-10 mRNA levels in tissue. The deficient progression was probably due to lesser mRNA expression of the Th1 driving cytokines IL-12 and IL-18 by the innate immune system (p < 0.05). Furthermore, the mRNA expression of inducible NO synthase, a marker of destructive insulitis, was also not up-regulated in the IL-18-treated group. IL-18 did not exert its effect at the levels of islet cells. Cultivation of islets with IL-18 affected NO production or mitochondrial activity and did not protect from the toxicity mediated by IL-1beta, TNF-alpha, and IFN-gamma. In conclusion, we show for the first time that administration of IL-18, a mediator of the innate immune system, suppresses autoimmune diabetes in nonobese diabetic mice by targeting the Th1/Th2 balance of inflammatory immune reactivity in the pancreas.     

Th1 and Th2 pancreatic inflammation differentially affects homing of islet-reactive CD4 cells in nonobese diabetic mice

The control of lymphocyte recruitment to the site of inflammation is an important component determining the pathogenicity of an autoimmune response. Progression from insulitis to diabetes in the nonobese diabetic mouse is typically associated with Th1 pancreatic inflammation, whereas Th2 inflammation can seemingly be controlled indefinitely. We show that a Th1 (IFN-gamma) pancreatic environment greatly accelerates the recruitment of adoptively transferred islet-specific CD4 T cells to the islets and also accelerates the onset of diabetes. The increased number of islet-reactive T cells in the pancreas does not result from increased proliferation or a decreased rate of apoptosis; instead, it appears to be caused by a greatly facilitated rate of entry to the pancreas. In contrast, a Th2 (IL-4) pancreatic environment does act to enhance Ag-specific proliferation and decrease the rate of apoptosis in islet-specific CD4 T cells. Nonpathogenic/regulatory cells are not preferentially expanded by the presence of IL-4. Increased recruitment to the islets was also observed in the presence of IL-4, but to a lesser extent than in the presence of IFN-gamma, and this lesser increase in the rate of recruitment did not accelerate diabetes onset within the time period examined. Therefore, the production of Th1 cytokines by initial islet-infiltrating cells may cause a greater increase than Th2 cytokines in the rate of recruitment of activated T cells. This difference in rate of recruitment may be critical in determining whether the initial infiltrate proceeds to diabetes or whether a steady state insulitis develops that can be maintained.     

Induction of diabetes in nonobese diabetic mice by Th2 T cell clones from a TCR transgenic mouse

We have produced a panel of cloned T cell lines from the BDC-2.5 TCR transgenic (Tg) mouse that exhibit a Th2 cytokine phenotype in vitro but are highly diabetogenic in vivo. Unlike an earlier report in which T cells obtained from the Tg mouse were cultured for 1 wk under Th2-promoting conditions and were found to induce disease only in NOD.scid recipients, we found that long-term T cell clones with a fixed Th2 cytokine profile can transfer disease only to young nonobese diabetic (NOD) mice and never to NOD.scid recipients. Furthermore, the mechanism by which diabetes is transferred by a Tg Th2 T cell clone differs from that of the original CD4+ Th1 BDC-2.5 T cell clone made in this laboratory. Whereas the BDC-2.5 clone rapidly causes disease in NOD.scid recipients less than 2 wk old, the Tg Th2 T cell clones can do so only when cotransferred with other diabetogenic T cells, suggesting that the Th2 T cell requires the presence of host T cells for initiation of disease.     

Human monoclonal antibodies isolated from type I diabetes patients define multiple epitopes in the protein tyrosine phosphatase-like IA-2 antigen

Protein tyrosine phosphatase-like IA-2 autoantigen is one of the major targets of humoral autoimmunity in patients with insulin-dependant diabetes mellitus (IDDM). In an effort to define the epitopes recognized by autoantibodies against IA-2, we generated five human mAbs (hAbs) from peripheral B lymphocytes isolated from patients most of whom had been recently diagnosed for IDDM. Determination and fine mapping of the critical regions for autoantibody binding was performed by RIA using mutant and chimeric constructs of IA-2- and IA-2beta-regions. Four of the five IgG autoantibodies recognized distinct epitopes within the protein tyrosine phosphatase (PTP)-like domain of IA-2. The minimal region required for binding by three of the PTP-like domain-specific hAbs could be located to aa 777-979. Two of these hAbs cross-reacted with the related IA-2beta PTP-like domain (IA-2beta aa 741-1033). A further PTP-like domain specific hAb required the entire PTP-like domain (aa 687-979) for binding, but critical amino acids clustered in the N-terminal region 687-777. An additional epitope could be localized within the juxtamembrane domain (aa 603-779). In competition experiments, the epitope recognized by one of the hAbs was shown to be targeted by 10 of 14 anti-IA-2-positive sera. Nucleotide sequence analysis of this hAb revealed that it used a V(H) germline gene (DP-71) preferably expressed in autoantibodies associated with IDDM. The presence of somatic mutations in both heavy and light chain genes and the high affinity or this Ab suggest that the immune response to IA-2 is Ag driven.     

NK T cell-induced protection against diabetes in V alpha 14-J alpha 281 transgenic nonobese diabetic mice is associated with a Th2 shift circumscribed regionally to the islets and functionally to islet autoantigen

The onset of autoimmune diabetes is related to defective immune regulation. Recent studies have shown that NK T cells are deficient in number and function in both diabetic patients and nonobese diabetic (NOD) mice. NK T cells, which are CD1d restricted, express a TCR with an invariant V alpha 14-J alpha 281 chain and rapidly produce large amounts of cytokines. V alpha 14-J alpha 281 transgenic NOD mice have increased numbers of NK T cells and are protected against diabetes onset. In this study we analyzed where and how NK T cells interfere with the development of the anti-islet autoimmune response. NK T cells, which are usually rare in lymph nodes, are abundant in pancreatic lymph nodes and are also present in islets. IL-4 mRNA levels are increased and IFN-gamma mRNA levels decreased in islets from diabetes-free V alpha 14-J alpha 281 transgenic NOD mice; the IgG1/IgG2c ratio of autoantibodies against glutamic acid decarboxylase is also increased in these mice. Treatment with IL-12 (a pro-Th1 cytokine) or anti-IL-4 Ab abolishes the diabetes protection in V alpha 14-J alpha 281 NOD mice. The protection from diabetes conferred by NK T cells is thus associated with a Th2 shift within islets directed against autoantigen such as glutamic acid decarboxylase. Our findings also demonstrate the key role of IL-4.     

The role of Gr1+ cells after anti-CD20 treatment in type 1 diabetes in nonobese diabetic mice

Studies suggest that Gr1(+)CD11b(+) cells have immunoregulatory function, and these cells may play an important role in autoimmune diseases. In this study, we investigated the regulatory role of Gr1(+)CD11b(+) cells in protecting against type 1 diabetes in NOD mice. In this study, we showed that temporary B cell depletion induced the expansion of Gr1(+)CD11b(+) cells. Gr1(+)CD11b(+) cells not only directly suppress diabetogenic T cell function but also can induce regulatory T cell differentiation in a TGF-β-dependent manner. Furthermore, we found that Gr1(+)CD11b(+) cells could suppress diabetogenic CD4 and CD8 T cell function in an IL-10-, NO-, and cell contact-dependent manner. Interestingly, single anti-Gr1 mAb treatment can also induce a transient expansion of Gr1(+)CD11b(+) cells that delayed diabetes development in NOD mice. Our data suggest that Gr1(+)CD11b(+) cells contribute to the establishment of immune tolerance to pancreatic islet autoimmunity. Manipulation of Gr1(+)CD11b(+) cells could be considered as a novel immunotherapy for the prevention of type 1 diabetes.