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1.
Diabetes ; 61(5): 1160-8, 2012 May.
Article in English | MEDLINE | ID: mdl-22368175

ABSTRACT

In earlier studies of the Iddm14 diabetes susceptibility locus in the rat, we identified an allele of the T-cell receptor (TCR) ß-chain, Tcrb-V13S1A1, as a candidate gene. To establish its importance, we treated susceptible rats with a depleting anti-rat Vß13 monoclonal antibody and then exposed them to either polyinosinic:polycytidylic acid or a diabetogenic virus to induce diabetes. The overall frequency of diabetes in the controls was 74% (n = 50), compared with 17% (n = 30) in the anti-Vß13-treated animals, with minimal islet pathology in nondiabetic treated animals. T cells isolated from islets on day 5 after starting induction showed a greater proportion of Vß13(+) T cells than did peripheral lymph node T cells. Vß13 transcripts recovered from day 5 islets revealed focused Jß usage and less CDR3 diversity than did transcripts from peripheral Vß13(+) T cells. CDR3 usage was not skewed in control Vß16 CDR3 transcripts. Anti-rat Vß13 antibody also prevented spontaneous diabetes in BBDP rats. The Iddm14 gene is likely to be Tcrb-V13, indicating that TCR ß-chain usage is a determinant of susceptibility to autoimmune diabetes in rats. It may be possible to prevent autoimmune diabetes by targeting a limited element of the T-cell repertoire.


Subject(s)
Antibodies, Monoclonal/therapeutic use , Diabetes Mellitus, Type 1/prevention & control , Receptors, Antigen, T-Cell, alpha-beta/immunology , Alleles , Animals , Diabetes Mellitus, Type 1/genetics , Diabetes Mellitus, Type 1/immunology , Female , Gene Expression Regulation , Genetic Predisposition to Disease , Genetic Testing , Islets of Langerhans/cytology , Islets of Langerhans/metabolism , Male , Poly I-C/toxicity , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rats , Receptors, Antigen, T-Cell, alpha-beta/genetics , T-Lymphocytes/cytology , T-Lymphocytes/immunology , T-Lymphocytes/physiology
2.
Autoimmunity ; 44(2): 137-48, 2011 Mar.
Article in English | MEDLINE | ID: mdl-20695765

ABSTRACT

The adipokine, leptin, regulates blood glucose and the insulin secretory function of beta cells, while also modulating immune cell function. We hypothesized that the dual effects of leptin may prevent or suppress the autoreactive destruction of beta cells in a virally induced rodent model of type 1 diabetes. Nearly 100% of weanling BBDR rats treated with the combination of an innate immune system activator, polyinosinic:polycytidylic acid (pIC), and Kilham rat virus (KRV) become diabetic within a predictable time frame. We utilized this model to test the efficacy of leptin in preventing diabetes onset, remitting new onset disease, and preventing autoimmune recurrence in diabetic rats transplanted with syngeneic islet grafts. High doses of leptin delivered via an adenovirus vector (AdLeptin) or alzet pump prevented diabetes in>90% of rats treated with pIC+KRV. The serum hyperleptinemia generated by this treatment was associated with decreased body weight, decreased non-fasting serum insulin levels, and lack of islet insulitis in leptin-treated rats. In new onset diabetics, hyperleptinemia prevented rapid weight loss and diabetic ketoacidosis, and temporarily restored euglycemia. Leptin treatment also prolonged the survival of syngeneic islets transplanted into diabetic BBDR rats. In diverse therapeutic settings, we found leptin treatment to have significant beneficial effects in modulating virally induced diabetes. These findings merit further evaluation of leptin as a potential adjunct therapeutic agent for treatment of human type 1 diabetes.


Subject(s)
Diabetes Mellitus, Experimental/drug therapy , Diabetes Mellitus, Type 1/drug therapy , Leptin/therapeutic use , Parvoviridae Infections/immunology , Parvovirus/immunology , Animals , Blood Glucose , Diabetes Mellitus, Experimental/immunology , Diabetes Mellitus, Experimental/pathology , Diabetes Mellitus, Experimental/virology , Diabetes Mellitus, Type 1/pathology , Diabetes Mellitus, Type 1/virology , Diabetic Ketoacidosis/prevention & control , Humans , Islets of Langerhans Transplantation , Leptin/administration & dosage , Leptin/immunology , Parvoviridae Infections/virology , Poly I-C/administration & dosage , Poly I-C/immunology , Rats , Rats, Inbred BB , Treatment Outcome
3.
Diabetes ; 59(1): 110-8, 2010 Jan.
Article in English | MEDLINE | ID: mdl-19794063

ABSTRACT

OBJECTIVE: The contribution of antecedent viral infection to the development of type 1 diabetes in humans is controversial. Using a newer rat model of the disease, we sought to 1) identify viruses capable of modulating diabetes penetrance, 2) identify conditions that increase or decrease the diabetogenicity of infection, and 3) determine whether maternal immunization would prevent diabetes. RESEARCH DESIGN AND METHODS: About 2% of LEW*1WR1 rats develop spontaneous autoimmune diabetes, but disease penetrance is much higher if weanling rats are exposed to environmental perturbants including Kilham rat virus (KRV). We compared KRV with other viruses for diabetogenic activity. RESULTS: Both KRV and rat cytomegalovirus (RCMV) induced diabetes in up to 60% of LEW*1WR1 rats, whereas H-1, vaccinia, and Coxsackie B4 viruses did not. Simultaneous inoculation of KRV and RCMV induced diabetes in 100% of animals. Pretreatment of rats with an activator of innate immunity increased the diabetogenicity of KRV but not RCMV and was associated with a moderate rate of diabetes after Coxsackie B4 and vaccinia virus infection. Inoculation of LEW*1WR1 dams with both KRV and RCMV prior to pregnancy protected weanling progeny from virus-induced diabetes in a virus-specific manner. CONCLUSIONS: Exposure to viruses can affect the penetrance of autoimmune diabetes in genetically susceptible animals. The diabetogenicity of infection is virus specific and is modified by immunomodulation prior to inoculation. Maternal immunization protects weanlings from virus-induced diabetes, suggesting that modification of immune responses to infection could provide a means of preventing islet autoimmunity.


Subject(s)
Diabetes Mellitus, Type 1/prevention & control , Diabetes Mellitus, Type 1/virology , Immunization/methods , Virus Diseases/complications , Virus Diseases/immunology , Animals , Cytomegalovirus Infections/immunology , Diabetes Mellitus, Type 1/genetics , Diabetes Mellitus, Type 1/immunology , Enterovirus B, Human/immunology , Enterovirus Infections/immunology , Female , Humans , Models, Animal , Poly I-C/immunology , Pregnancy , Rats , Rats, Inbred Lew , Rats, Inbred Strains , Vaccinia virus/immunology
4.
Ann N Y Acad Sci ; 1103: 128-31, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17376830

ABSTRACT

Iddm4 is a dominant non-major histocompatibility complex (MHC) determinant of diabetes susceptibility in BBDR rats treated with poly I:C, plus depletion of regulatory T cells. In congenic MHC-identical normal WF rats, Iddm4(d) sensitively and specifically predicts induced diabetes. We report a new diabetes-susceptible subcongenic line that carries Iddm4 in a < 2.6 megabase interval. Candidate genes include the T cell receptor beta chain variable (TCRVbeta) family. We found that TCRVbeta4 in WF rats contains a stop codon, whereas 5/5 diabetes-susceptible rat strains express TCRVbeta4. We conclude that Iddm4-mediated diabetes resistance in rats may be due to a recessive protective mutation in TCRVbeta4.


Subject(s)
Diabetes Mellitus, Type 1/genetics , Diabetes Mellitus, Type 1/immunology , Immunoglobulin Variable Region , Receptors, Antigen, T-Cell, alpha-beta/genetics , Animals , Base Sequence , Chromosome Mapping , Crosses, Genetic , DNA Primers , Disease Models, Animal , Female , Male , Rats , Rats, Inbred Strains
5.
Diabetes ; 54(9): 2727-33, 2005 Sep.
Article in English | MEDLINE | ID: mdl-16123363

ABSTRACT

We describe a new rat model of autoimmune diabetes that arose in a major histocompatibility complex congenic LEW rat. Spontaneous diabetes in LEW.1WR1 rats (RT1(u/u/a)) occurs with a cumulative frequency of approximately 2% at a median age of 59 days. The disease is characterized by hyperglycemia, glycosuria, ketonuria, and polyuria. Both sexes are affected, and islets of acutely diabetic rats are devoid of beta-cells, whereas alpha- and delta-cell populations are spared. The peripheral lymphoid phenotype is normal, including the fraction of ART2(+) regulatory T-cells. We tested the hypothesis that the expression of diabetes would be increased by immunological perturbation of innate or adaptive immunity. Treatment of young rats with depleting anti-ART2.1 monoclonal antibody increased the frequency of diabetes to 50%. Treatment with the toll-like receptor 3 ligand polyinosinic:polycytidylic acid increased the frequency of diabetes to 100%. All diabetic rats exhibited end-stage islets. The LEW.1WR1 rat is also susceptible to collagen-induced arthritis but is free of spontaneous thyroiditis. The LEW.1WR1 rat provides a new model for studying autoimmune diabetes and arthritis in an animal with a genetic predisposition to both disorders that can be amplified by environmental perturbation.


Subject(s)
Diabetes Mellitus/genetics , Diabetes Mellitus/physiopathology , Animals , Antibodies, Monoclonal/pharmacology , Arthritis/chemically induced , Collagen/toxicity , Disease Models, Animal , Female , Lipopolysaccharides/pharmacology , Male , Poly I-C/pharmacology , Rats , Time Factors
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