T cell activation and anergy to islet cell antigen in type I diabetes.
J Immunol
; 154(3): 1461-9, 1995 Feb 01.
Article
in En
| MEDLINE
| ID: mdl-7822811
ABSTRACT
Early exposure to cow milk proteins was linked to the development of type I diabetes by consistent epidemiology, and by feeding and tolerization studies in diabetes-prone rodents. Dietary BSA was suggested as the culprit because patients and relevant rodents have elevated anti-BSA Abs that precipitate the recently cloned protein, p69, from beta cell lysates. A total of 68 of 78 children with recent onset diabetes had BSA-reactive T cells at the time of diagnosis. Here we 1) map the fine specificity of these T cells, 2) delineate a homologous peptide sequence near the N-terminus of p69, and 3) demonstrate T cell recognition of this p69 sequence (T cell epitope p69, Tep69) by patient T cells. The Tep69 sequence is conserved in p69 of patients and diabetes-prone rodents. Whereas BSA triggers T cell proliferation, recombinant p69 and a synthetic Tep69 peptide induce early stages of T cell activation (IL-2R transcription) but insufficient IL-2 production and thus anergy. Exogenous IL-2 overrides anergy and allows proliferative expansion of p69-responsive T cells. In mixing experiments, p69 and Tep69 peptide prevented proliferative responses to BSA even at 100-fold smaller concentrations. These findings imply that high-affinity self-peptide triggers anergy, whereas low-affinity mimicry Ag triggers proliferative expansion of these T cells. This implies a disease model in which mimicry Ag would rescue autoreactive cells from ablation by self-Ag.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Autoantigens
/
Lymphocyte Activation
/
Islets of Langerhans
/
Clonal Anergy
/
Diabetes Mellitus, Type 1
Type of study:
Prognostic_studies
Limits:
Adolescent
/
Child
/
Female
/
Humans
/
Male
Language:
En
Journal:
J Immunol
Year:
1995
Document type:
Article
Affiliation country:
Canada
Publication country:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA