Comprehensive mapping of HLA-A0201-restricted CD8 T-cell epitopes on PDC-E2 in primary biliary cirrhosis.
Growing evidence has implicated the involvement of autoreactive T lymphocytes in the pathogenesis of primary biliary cirrhosis (PBC). We have recently taken advantage of motif prediction analysis of HLA-A*0201 and identified the first major histocompatibility complex (MHC) class I restricted epitope, amino acids 159 to 167 on E2 components of pyruvate dehydrogenase complexes (PDC-E2), the major mitochondrial antigens in PBC. The mechanisms involved in the selection of epitope peptide(s) that comprise the PDC-E2-specific autoreactive cytotoxic T lymphocytes (CTLs) are unknown and likely involve other epitopes on PDC-E2 restricted by MHC class I molecules. To address this issue, a comprehensive mapping of the CTL epitope repertoire on the PDC-E2 molecule that binds HLA-A*0201 was performed to provide further clues regarding the role of CTLs. We used the T2 cell line to screen 79 overlapping 15mer peptides, spanning the entire PDC-E2 molecule. Six of the 79 peptides exhibited significantly higher binding activity to HLA-A*0201 than the other 15mer peptides. Two of these 6 peptides induced CTL lines from patients with PBC. Fine mapping with N-terminus or C-terminus truncated peptides identified 10mer peptide, PDC-E2 amino acids 165 to 174, which is a novel CD8 epitope restricted by HLA-A*0201. In conclusion, using a combination of the 15mer peptide library screening with the T2 binding assay and also the induction of CTL lines with candidate peptides, we have defined a novel HLA-A*0201-restricted epitope PDC-E2 165 to 174 in patients with PBC. These data will become important in the development of altered peptide ligands to modulate disease activity.
Matsumura
Shuji
S
Division of Rheumatology, Allergy, and Clinical Immunology, University of California at Davis, 95616, USA.
Kita
Hiroto
H
He
Xiao-Song
XS
Ansari
Aftab A
AA
Lian
Zhe-Xiong
ZX
Van De Water
Judy
J
Yamamoto
Kazuhide
K
Tsuji
Takao
T
Coppel
Ross L
RL
Kaplan
Marshall
M
Gershwin
M Eric
ME
D000595:Amino Acid Sequence; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D002460:Cell Line; D051047:Dihydrolipoyllysine-Residue Acetyltransferase; D018604:Epitope Mapping; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D015234:HLA-A Antigens / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D015789:HLA-A2 Antigen; D006801:Humans; D008105:Liver Cirrhosis, Biliary / Q000235:genetics* / Q000276:immunology*; D010641:Phenotype; D011485:Protein Binding; D011768:Pyruvate Dehydrogenase Complex / Q000235:genetics* / Q000276:immunology / Q000378:metabolism
D018984:Epitopes, T-Lymphocyte; D015234:HLA-A Antigens; C435939:HLA-A*02:01 antigen; D015789:HLA-A2 Antigen; D011768:Pyruvate Dehydrogenase Complex; D051047:Dihydrolipoyllysine-Residue Acetyltransferase