Abstract
We previously demonstrated that administration of plasmid DNAs (pDNAs) encoding IL-4 and a fragment of glutamic acid decarboxylase 65 (GAD65) fused to IgGFc induces GAD65-specific Th2 cells and prevents insulin-dependent diabetes mellitus (IDDM) in nonobese diabetic (NOD) mice. To assess the general applicability of pDNA vaccination to mediate Ag-specific immune deviation, we examined the immunotherapeutic efficacy of recombinants encoding murine insulin A and B chains fused to IgGFc. Insulin was chosen based on studies demonstrating that administration of insulin or insulin B chain by a variety of strategies prevents IDDM in NOD mice. Surprisingly, young NOD mice receiving i.m. injections of pDNA encoding insulin B chain-IgGFc with or without IL-4 exhibited an accelerated progression of insulitis and developed early diabetes. Exacerbation of IDDM correlated with an increased frequency of IFN-gamma-secreting CD4(+) and CD8(+) T cells in response to insulin B chain-specific peptides compared with untreated mice. In contrast, treatment with pDNAs encoding insulin A chain-IgGFc and IL-4 elicited a low frequency of IL-4-secreting Th cells and had no effect on the progression of IDDM. Vaccination with pDNAs encoding GAD65-IgGFc and IL-4, however, prevented IDDM. These results demonstrate that insulin- and GAD65-specific T cell reactivity induced by pDNA vaccination has distinct effects on the progression of IDDM.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Aging / immunology
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Animals
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CD4-Positive T-Lymphocytes / immunology
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CD8-Positive T-Lymphocytes / immunology
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Diabetes Mellitus, Type 1 / etiology
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Diabetes Mellitus, Type 1 / immunology*
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Diabetes Mellitus, Type 1 / pathology
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Diabetes Mellitus, Type 1 / prevention & control*
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Disease Progression
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Epitopes, T-Lymphocyte / immunology
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Female
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Glutamate Decarboxylase / administration & dosage
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Glutamate Decarboxylase / genetics*
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Glutamate Decarboxylase / immunology
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Immunoglobulin Fc Fragments / administration & dosage
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Immunoglobulin Fc Fragments / genetics
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Immunoglobulin G / administration & dosage
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Immunoglobulin G / genetics
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Injections, Intramuscular
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Insulin / administration & dosage
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Insulin / genetics*
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Insulin / immunology
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Interleukin-4 / administration & dosage
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Interleukin-4 / genetics
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Isoenzymes / administration & dosage
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Isoenzymes / genetics*
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Isoenzymes / immunology
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Lymphocyte Activation / genetics
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Lymphocyte Count
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Mice
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Mice, Inbred NOD
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Plasmids / administration & dosage
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Plasmids / immunology*
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Recombinant Fusion Proteins / administration & dosage
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Recombinant Fusion Proteins / immunology
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Th1 Cells / pathology
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Vaccines, DNA / administration & dosage
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Vaccines, DNA / immunology*
Substances
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Epitopes, T-Lymphocyte
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Immunoglobulin Fc Fragments
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Immunoglobulin G
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Insulin
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Isoenzymes
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Recombinant Fusion Proteins
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Vaccines, DNA
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Interleukin-4
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Glutamate Decarboxylase
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glutamate decarboxylase 2