HLA-B7-restricted islet epitopes are differentially recognized in type 1 diabetic children and adults and form weak peptide-HLA complexes.
Diabetes
; 61(10): 2546-55, 2012 Oct.
Article
em En
| MEDLINE
| ID: mdl-22997432
ABSTRACT
The cartography of ß-cell epitopes targeted by CD8(+) T cells in type 1 diabetic (T1D) patients remains largely confined to the common HLA-A2 restriction. We aimed to identify ß-cell epitopes restricted by the HLA-B7 (B*0702) molecule, which is associated with mild T1D protection. Using DNA immunization on HLA-B7-transgenic mice and prediction algorithms, we identified GAD and preproinsulin candidate epitopes. Interferon-γ (IFN-γ) enzyme-linked immunospot assays on peripheral blood mononuclear cells showed that most candidates were recognized by new-onset T1D patients, but not by type 2 diabetic and healthy subjects. Some epitopes were highly immunodominant and specific to either T1D children (GAD(530-538); 44% T cell-positive patients) or adults (GAD(311-320); 38%). All epitopes displayed weak binding affinity and stability for HLA-B7 compared with HLA-A2-restricted ones, a general feature of HLA-B7. Single-cell PCR analysis on ß-cell-specific (HLA-B7 tetramer-positive) T cells revealed uniform IFN-γ and transforming growth factor-ß (TGF-ß) mRNA expression, different from HLA-A2-restricted T cells. We conclude that HLA-B7-restricted islet epitopes display weak HLA-binding profiles, are different in T1D children and adults, and are recognized by IFN-γ(+)TGF-ß(+)CD8(+) T cells. These features may explain the T1D-protective effect of HLA-B7. The novel epitopes identified should find valuable applications for immune staging of HLA-B7(+) individuals.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Antígeno HLA-B7
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Diabetes Mellitus Tipo 1
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Células Secretoras de Insulina
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Epitopos
Tipo de estudo:
Prognostic_studies
Limite:
Adolescent
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Adult
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Aged
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Animals
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Child
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Child, preschool
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article