T cells in peripheral blood after gluten challenge in coeliac disease.
BACKGROUND
Current understanding of T cell epitopes in coeliac disease (CD) largely derives from intestinal T cell clones in vitro. T cell clones allow identification of gluten peptides that stimulate T cells but do not quantify their contribution to the overall gluten specific T cell response in individuals with CD when exposed to gluten in vivo.


OBJECTIVE
To determine the contribution of a putative dominant T cell epitope to the overall gliadin T cell response in HLA-DQ2 CD in vivo.


METHODS
HLA-DQ2+ individuals with CD and healthy controls.


METHODS
Subjects consumed 20 g of gluten daily for three days. Interferon gamma (IFN-gamma) ELISPOT was performed using peripheral blood mononuclear cells (PBMC) to enumerate and characterise peptide and gliadin specific T cells before and after gluten challenge.


RESULTS
In 50/59 CD subjects, irrespective of homo- or heterozygosity for HLA-DQ2, IFN-gamma ELISPOT responses for an optimal concentration of A-gliadin 57-73 Q-E65 were between 10 and 1500 per million PBMC, equivalent to a median 51% of the response for a "near optimal" concentration of deamidated gliadin. Whole deamidated gliadin and gliadin epitope specific T cells induced in peripheral blood expressed an intestinal homing integrin (alpha4beta7) and were HLA-DQ2 restricted. Peripheral blood T cells specific for A-gliadin 57-73 Q-E65 are rare in untreated CD but can be predictably induced two weeks after gluten exclusion.


CONCLUSIONS
In vivo gluten challenge is a simple safe method that allows relevant T cells to be analysed and quantified in peripheral blood by ELISPOT, and should permit comprehensive high throughput mapping of gluten T cell epitopes in large numbers of individuals with CD.
Anderson
R P
RP
Autoimmunity and Transplantation Division, Walter and Eliza Hall Institute, c/o Post Office RMH, Victoria, Australia 3050. banderson@wehi.edu.au
van Heel
D A
DA
Tye-Din
J A
JA
Barnardo
M
M
Salio
M
M
Jewell
D P
DP
Hill
A V S
AV
D000328:Adult; D000368:Aged; D000941:Antigens; D016022:Case-Control Studies; D002446:Celiac Disease / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D018984:Epitopes, T-Lymphocyte; D005260:Female; D005903:Gliadin / Q000276:immunology; D005983:Glutens; D006683:HLA-DQ Antigens / Q000032:analysis; D006801:Humans; D007111:Immunity, Cellular; D016130:Immunophenotyping; D016023:Integrins / Q000032:analysis; D007371:Interferon-gamma / Q000276:immunology; D007413:Intestinal Mucosa / Q000276:immunology; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D013601:T-Lymphocytes / Q000276:immunology*
D000941:Antigens; D018984:Epitopes, T-Lymphocyte; D006683:HLA-DQ Antigens; C053186:HLA-DQ2 antigen; D016023:Integrins; D010446:Peptide Fragments; C071777:integrin alpha4beta7; D005983:Glutens; D007371:Interferon-gamma; D005903:Gliadin