Abstract
The low frequency of islet-cell antigen-reactive T cells in type 1 diabetes makes their direct measurement difficult. Commonly used in vitro expansion could alter in vivo frequencies and Th1/Th2 differentiation states. Using IFN-gamma/IL-4 double color ELISPOT, we tested longitudinally the reactivity of PBMC from HLA-matched diabetic patients and healthy controls to GAD65, IA-2, and proinsulin peptides ex vivo and after in vitro culture. The peptide-reactive T cells showed IFN-gamma bias in the patients' PBMC in the primary assay. During in vitro culture, both IFN-gamma- and IL-4-producing cells were induced in controls, suggesting that the precursor cells were uncommitted naive T cells in vivo. In contrast, in diabetic patients, the ex vivo IFN-gamma response was conserved during culture, suggesting their Th1 commitment. Using CFSE-dye-dilution, we demonstrate that naive T cells expand in vitro at a faster rate than memory cells, which might account for the differences in expansion rates between diabetic patients and controls.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adult
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Amino Acid Sequence
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Autoantigens / immunology
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Cell Differentiation / immunology
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Diabetes Mellitus, Type 1 / immunology*
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Flow Cytometry
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Glutamate Decarboxylase / immunology
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Humans
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Immunologic Memory / immunology
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Interferon-gamma / immunology
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Interleukin-4 / immunology
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Islets of Langerhans / immunology*
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Isoenzymes / immunology
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Lymphocyte Activation
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Membrane Proteins / immunology
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Molecular Sequence Data
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Peptide Fragments / immunology
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Proinsulin / immunology
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Protein Tyrosine Phosphatase, Non-Receptor Type 1
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Protein Tyrosine Phosphatases / immunology
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Receptor-Like Protein Tyrosine Phosphatases, Class 8
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Th1 Cells / cytology
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Th1 Cells / immunology*
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Th2 Cells / cytology
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Th2 Cells / immunology*
Substances
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Autoantigens
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Isoenzymes
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Membrane Proteins
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Peptide Fragments
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Interleukin-4
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Interferon-gamma
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Proinsulin
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PTPRN protein, human
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Protein Tyrosine Phosphatase, Non-Receptor Type 1
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Protein Tyrosine Phosphatases
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Receptor-Like Protein Tyrosine Phosphatases, Class 8
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Glutamate Decarboxylase
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glutamate decarboxylase 2