Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011854 (type 1 diabetes)
 20,749 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The major predisposing genetic component in type 1 diabetes maps to the major histocompatibility complex locus in both mice and humans. To verify the HLA class II association with disease pathogenesis, we adopted the transgenic approach. Expression of HLA-DQ8, the molecule showing the strongest association with human type 1 diabetes, in the diabetes-predisposing milieu of NOD mice in the absence of the endogenous class II molecule I-A(g7) did not render susceptibility to type 1 diabetes. To study if providing a local proinflammatory environment would lead to diabetes in these mice, Abeta(o).NOD.DQ8 were bred with C57BL/6 mice expressing tumor necrosis factor (TNF)-alpha in the beta-cells of the islets of Langerhans. Surprisingly, although diabetes was evident in the F1 intercross expressing rat insulin promoter (RIP)-TNF, offspring lacking either endogenous or transgenic class II molecules developed accelerated diabetes with high frequency in both sexes. Moreover, expression of any functional class II molecule seemed to confer significant protection from diabetes in this model. Thus, neonatal expression of TNF-alpha in an islet-specific manner bypassed the requirement of CD4(+) T-cells and resulted in diabetes that could be mediated by CD8(+) T-cells. We also show for the first time that diabetes in NOD.RIP-TNF mice can occur independent of inheritance of NOD-derived idd1.
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PMID:Accelerated diabetes in rat insulin promoter-tumor necrosis factor-alpha transgenic nonobese diabetic mice lacking major histocompatibility class II molecules. 1254 Jun 6

Many autoimmune diseases have genetic associations with the Major Histocompatibility Complex (MHC) class II loci. Susceptibility to Type 1 diabetes mellitus (TIDM) is particularly associated with Human Leucocyte Antigen (HLA) DR3, 4 and associated DQ2, 8 alleles and this is well documented in genetic association studies. These molecules play an important role in presentation of peptide antigens after intracellular processing to CD4 T lymphocytes. During the last decade, a number of approaches have been used to elucidate the molecular basis for the association of particular alleles with susceptibility to or protection from TIDM. These studies have focused on investigating the structure of the antigen presenting molecules, together with their peptides. Through binding studies, peptide elution, molecular modelling and crystallization of the peptide MHC complex, it has been possible to define the peptide binding regions and examine the stability of binding of peptides from putative autoantigens. This knowledge has also facilitated the development of reagents such as multimeric MHC-peptide complexes that will help to track the low frequency, potentially pathogenic antigen specific cells. Recently, HLA transgenic mice have been generated and used to study T cell epitopes. In addition, although it is clear that the presence of HLA molecules alone does not by itself cause disease, these transgenic mice will develop diabetes when there is an islet "insult", even if the islet "insult" is, itself, not sufficient to precipitate disease in the absence of the HLA class II transgene. These mice will allow further study of the role of these HLA molecules in vivo. We now have a much greater general understanding of the possible reasons why particular molecules may encode susceptibility to or protection from disease. All these studies will provide information to ultimately define a rational basis for the development of targeted immunotherapy.
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PMID:The study of HLA class II and autoimmune diabetes. 1255 70

Idiopathic dilated cardiomyopathy (IDC) is one of the major causes of death in humans and has been linked to Coxsackievirus B (CVB) infection. The aim of this study was to analyze phenotypes of heart-infiltrating immune cells in patients suffering from myocarditis and IDC associated with CVB infections. We found that the myocardium of these patients was infiltrated by CD4(+) and CD8(+) T lymphocytes as well as macrophages. Evidence of CVB3/4 infections was also found. In the majority of patients, the T-cell receptor repertoire (TCR) of the infiltrating lymphocytes was restricted, with a polyclonal expansion of the Vbeta7 gene family. We also found that human leukocyte antigen (HLA) class II alleles associated with susceptibility to type 1 diabetes (HLA-DR4 and HLA-DQA1*04/05/06 alleles) were remarkably infrequent in IDC patients (p < 0.005), thus suggesting that they might confer protection against IDC. Finally, mRNA for interleukin-1beta, interferon-gamma, and tumor necrosis factor-alpha was detected in the cardiac specimens, although at a lower level compared with specimens from hearts without signs of viral infections. We conclude that CVB infection of the human myocardium is associated with a selective, yet polyclonal activation of different T-cell subsets in genetically susceptible individuals. This immune response may play a critical role in modulating disease progression after viral infections.
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PMID:Expansion of specific alphabeta+ T-cell subsets in the myocardium of patients with myocarditis and idiopathic dilated cardiomyopathy associated with Coxsackievirus B infection. 1255 22

Dimeric Fc receptor (FcR) nonbinding anti-CD3 antibodies have been developed to minimize toxicities associated with classical anti-CD3 monoclonal antibodies (e.g., OKT3). Studies with murine analogs of non-FcR-binding antibodies have shown reduced mitogenicity compared to OKT3. In a trial of an FcR nonbinding humanized anti-CD3 mAb hOKT3gamma1(Ala-Ala) for treatment of patients with type 1 diabetes, we found significant increases in IL-10 and IL-5 in the serum of 63% and 72% of patients, respectively, and TNF-alpha and IL-6 levels that were lower than those previously reported following OKT3 therapy. The activation signal delivered by hOKT3gamma1(Ala-Ala) was associated with calcium signaling and cytokine production by previously activated human cells in vitro. However, the production of IL-10, compared to IFN-gamma on a molar basis, was greater after culture with hOKT3gamma1(Ala-Ala) than with OKT3. Flow cytometric studies confirmed that OKT3 induced IFN-gamma and IL-10 production, but hOKT3gamma1(Ala-Ala) induced only detectable IL-10 production in CD45RO(+) cells. Moreover, in vivo, we found IL-10(+)CD4(+) T cells after drug treatment. These cells were heterogeneous but generally CD45RO(+), CTLA-4(-), and expressed CCR4. A subgroup of these cells expressed TGF-beta. Thus, the non-FcR binding anti-CD3 mAb, hOKT3gamma1(Ala-Ala) delivers an activation signal to T cells that is quantitatively and qualitatively different from OKT3. It leads to the generation of T cells that might inhibit the autoimmune response and may be involved in the beneficial effect on beta cell destruction in Type 1 diabetes.
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PMID:Activation of human T cells by FcR nonbinding anti-CD3 mAb, hOKT3gamma1(Ala-Ala). 1256 67

Type 1 diabetes is characterized by a chronic inflammatory response resulting in the selective destruction of the insulin-producing beta cells. We have previously demonstrated that dendritic cells (DCs) prepared from nonobese diabetic (NOD) mice, a model for spontaneous type 1 diabetes, exhibit hyperactivation of NF-kappaB resulting in an increased capacity to secrete proinflammatory cytokines and stimulate T cells compared with DCs of nondiabetic strains of mice. In the current study, the activational status of NF-kappaB and its role in regulating the APC function of macrophages (Mphi) prepared from NOD, nonobese resistant (NOR), and BALB/c mice was investigated. Independent of the stimulus, splenic and bone marrow-derived Mphi prepared from NOD mice exhibited increased NF-kappaB activation relative to NOR and BALB/c Mphi. This hyperactivation was detected for different NF-kappaB complexes and correlated with increased IkappaBalpha degradation. Furthermore, increased NF-kappaB activation resulted in an enhanced capacity of NOD vs NOR or BALB/c Mphi to secrete IL-12(p70), TNF-alpha, and IL-1alpha, which was inhibited upon infection with an adenoviral recombinant encoding a modified form of IkappaBalpha. In contrast, elevated NF-kappaB activation had no significant effect on the capacity of NOD Mphi to stimulate CD4(+) or CD8(+) T cells in an Ag-specific manner. These results demonstrate that in addition to NOD DCs, NOD Mphi exhibit hyperactivation of NF-kappaB, which correlates with an increased ability to mediate a proinflammatory response. Furthermore, NF-kappaB influences Mphi APC function by regulating cytokine secretion but not T cell stimulation.
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PMID:NF-kappa B hyperactivation has differential effects on the APC function of nonobese diabetic mouse macrophages. 1257 41

In addition to providing a large source of donor tissue, xenogeneic islet transplantation might avoid recurrent autoimmunity in patients with type 1 diabetes. To examine this possibility further, xenogeneic pig islets were transplanted into recipient mice in the presence or absence of autoimmunity. Spontaneously, non-obese diabetic (NOD) recipients rejected isografts rapidly whether or not the recipients were depleted of CD4+ T-cells. Young NOD mice made diabetic with streptozotocin accepted islet isografts without immunosuppression, indicating that destructive autoimmunity did not develop in these recipients. Pig xenografts were rejected equally quickly in the two types of NOD recipients in the absence of immunosuppression and survived for up to 9 weeks in both types of NOD recipients after CD4 depletion. BALB/c mice often accepted pig xenografts indefinitely after anti-CD4 antibody treatment. These results suggest that pig islets are resistant to recurrent autoimmunity when CD4+ T-cells are depleted. The difficulty in obtaining indefinite islet xenograft survival in NOD recipients occurs independently from the development of destructive autoimmunity.
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PMID:Pig islet xenografts are resistant to autoimmune destruction by non-obese diabetic recipients after anti-CD4 treatment. 1258 50

Nonobese diabetic (NOD) mice and some human type 1 diabetes (T1D) patients manifest low to high levels of other autoimmune pathologies. Skewing their cytokine production from a Th1 (primarily IFN-gamma) to a Th2 (primarily IL-4 and IL-10) pattern is a widely proposed approach to dampen the pathogenicity of autoreactive diabetogenic T cells. However, it is important that altered cytokine balances not enhance any other autoimmune proclivities to dangerous levels. Murine CD4 T cells are characterized by a reciprocal relationship between the production of IFN-gamma and expression of the beta-chain component of its receptor (IFN-gamma RB). Thus, NOD mice constitutively expressing a CD2 promoter-driven IFN-gamma RB transgene in all T cells are Th1-deficient. Unexpectedly, NOD.IFN-gamma RB Tg mice were found to develop a lethal early paralytic syndrome induced by a CD8 T cell-dependent autoimmune-mediated myositis. Furthermore, pancreatic insulitis levels were not diminished in 9-wk-old NOD.IFN-gamma RB Tg females, and overt T1D developed in the few that survived to an older age. Autoimmune-mediated myositis is only occasionally detected in standard NOD mice. Hence, some manipulations diminishing Th1 responses can bring to the forefront what are normally secondary autoimmune pathologies in NOD mice, while also failing to dependably abrogate pancreatic beta cell destruction. This should raise a cautionary note when considering the use of protocols that induce alterations in cytokine balances as a means of blocking progression to overt T1D in at-risk humans.
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PMID:Paralytic autoimmune myositis develops in nonobese diabetic mice made Th1 cytokine-deficient by expression of an IFN-gamma receptor beta-chain transgene. 1259 5

T cells play a central role in the development of diabetes both in man and in the non-obese diabetic (NOD) mouse. Both the CD4(+) and CD8(+) subsets of T cells are required for the normal development of IDDM in NOD mice. Islet reactive CD4(+) T cells play a clear pathogenic role as evidenced from the isolation of diabetogenic CD4(+) T cell clones. CD8(+) T cells seem to be involved in the initiation of diabetes as lack of these cells leads to protection from diabetes. We have isolated a GAD(65) reactive, cytotoxic CD8(+) T cell clone R1 that produces large quantities of IFNgamma and accelerates the onset of insulitis. This clone proliferates and produces IFNgamma in response to GAD(65) presenting APCs and kills GAD(65) presenting targets. Furthermore, it expresses TNFalpha, CD25, CD28, CD44, CD45 and LFA1, but not CD95L This is the first example of a GAD(65)specific CD8(+) T cell clone that accelerates the onset of the insulitis, although it does not appear to accelerate the onset of diabetes.
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PMID:An islet-homing NOD CD8+ cytotoxic T cell clone recognizes GAD65 and causes insulitis. 1265 23

Nonobese diabetic (NOD) mice expressing the BDC2.5 TCR transgene are useful for studying type 1 diabetes. Several peptides have been identified that are highly active in stimulating BDC2.5 T cells. Herein, we describe the use of I-Ag7 tetramers containing two such peptides, p79 and p17, to detect and characterize peptide-specific T cells. The tetramers could stain CD4(+) T cells in the islets and spleens of BDC2.5 transgenic mice. The percentage of CD4(+), tetramer(+) T cells increased in older mice, and it was generally higher in the islets than in the spleens. Our results also showed that tetAg7/p79 could stain a small population of CD4(+) T cells in both islets and spleens of NOD mice. The percentage of CD4(+), tetramer(+) T cells increased in cells that underwent further cell division after being activated by peptides. The avidity of TCRs on purified tetAg7/p79(+) T cells for tetAg7/p79 was slightly lower than that of BDC2.5 T cells. Although tetAg7/p79(+) T cells, like BDC2.5 T cells, secreted a large quantity of IFN-gamma, they were biased toward being IL-10-producing cells. Additionally, <3% of these cells expressed TCR Vbeta4. In vivo adoptive transfer experiments showed that NOD/scid recipient mice cotransferred with tetAg7/p79(+) T cells and NOD spleen cells, like mice transferred with NOD spleen cells only, developed diabetes. Therefore, we have generated Ag-specific tetramers that could detect a heterogeneous population of T cells, and a very small number of NOD mouse T cells may represent BDC2.5-like cells.
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PMID:Detection and characterization of T cells specific for BDC2.5 T cell-stimulating peptides. 1268 29

Fas is a death receptor belonging to the TNFR superfamily and induces cell apoptosis by both activating a caspase cascade and altering mitochondria. In the immune system, Fas is involved in the switching-off of the immune responses and cell mediated cytotoxicity. In humans, genetic defects decreasing Fas function cause the Autoimmune Lymphoproliferative Syndrome (ALPS) where autoimmunities are associated with accumulation of polyclonal lymphocytes in the secondary lymphoid tissues and expansion of T cells lacking both CD4 and CD8 (DN cells). Expansion of DN cells is absent in an ALPS variant, named Dianzani's Autoimmune Lymphoproliferative Disease (DALD). The observation that DALD patients' families display increased frequency of autoimmune diseases different from ALPS suggests that defects of Fas function may also play a role in development of "common" autoimmune diseases. This possibility is supported by detection of defective Fas function in substantial proportions of patients with the multiple autoimmune syndrome or aggressive forms of type 1 diabetes or multiple sclerosis. This article reviews data suggesting that development of autoimmune/lymphoproliferative patterns may involve several alterations hitting the Fas system, but might also involve alterations in other systems contributing to the switching-off or proliferation of lymphocytes.
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PMID:Role of inherited defects decreasing Fas function in autoimmunity. 1269 65


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