Identification of CD4 T-cell epitopes in soluble liver antigen/liver pancreas autoantigen in autoimmune hepatitis.
OBJECTIVE
Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease associated with autoantibodies and liver-infiltrating lymphocytes. Although autoantibodies are tested routinely to diagnose and classify AIH, liver-infiltrating lymphocytes are regarded as the primary factor for disease pathogenesis. The purpose of this study was to identify and characterize autoantigenic peptides within human AIH-specific soluble liver antigen/liver pancreas antigen (SLA/LP) that are targeted by CD4(+) T cells and restricted by the disease susceptibility gene HLA-DRB1*0301.


METHODS
HLA-DRB1*0301 transgenic mice were immunized with SLA/LP. Antibody and T-cell responses were analyzed with SLA/LP-overlapping peptides in enzyme immunoassay, proliferation, and enzyme-linked immunospot (ELISpot) assays. Minimal optimal T-cell epitopes were identified, characterized with cloned T-cell hybridomas, and confirmed in tetramer and ELISpot assays with AIH patients' peripheral blood mononuclear cells.


RESULTS
All mice developed SLA/LP-specific IgG1/IgG2a antibodies against the same SLA/LP peptides as human beings. T cells targeted several peptides within SLA/LP, 2 of which were DR3-restricted and one overlapped the sequence recognized by human autoantibodies. Minimal optimal epitopes were mapped, DRB1*0301/epitope-tetramers were generated, and the frequency and function of HLA-DRB1*0301-restricted autoantigen-specific T cells in AIH patients were analyzed with tetramer and interferon-gamma ELISpot assays.


CONCLUSIONS
This study identified T-cell epitopes within SLA/LP, restricted by the disease susceptibility gene DRB1*0301 and in close proximity to the human autoantibody epitope. These results and the generated reagents now provide the opportunity to directly monitor autoreactive T cells in AIH patients in clinical studies.
Mix
Heiko
H
Immunology Section, Liver Diseases Branch, National Institute for Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892-1800, USA.
Weiler-Normann
Christina
C
Thimme
Robert
R
Ahlenstiel
Golo
G
Shin
Eui-Cheol
EC
Herkel
Johannes
J
David
Chella S
CS
Lohse
Ansgar W
AW
Rehermann
Barbara
B
D000328:Adult; D000368:Aged; D000818:Animals; D001323:Autoantibodies / Q000276:immunology / Q000378:metabolism; D001324:Autoantigens / Q000276:immunology / Q000378:metabolism*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D004195:Disease Models, Animal; D018984:Epitopes, T-Lymphocyte / Q000276:immunology / Q000378:metabolism*; D005260:Female; D019693:Hepatitis, Autoimmune / Q000276:immunology* / Q000473:pathology; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008875:Middle Aged; D055815:Young Adult
D001323:Autoantibodies; D001324:Autoantigens; D018984:Epitopes, T-Lymphocyte; C046431:liver antigen LA-1
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