Mimicry peptides of human PDC-E2 163-176 peptide, the immunodominant T-cell epitope of primary biliary cirrhosis.

Abstract

The human PDC-E2 163-176 peptide (GDLLAEIETDKATI) is an immunodominant autoreactive T-cell epitope in patients with primary biliary cirrhosis (PBC), restricted by HLA DRB4*0101. We have previously reported that the ExDK sequence is essential for recognition of this epitope and identified 1 mimicry peptide, Escherichia coli PDC-E2 peptide (EQSLITVEGDKASM), which can activate human PDC-E2 163-176 peptide-reactive T-cell clones. In the present study, to further investigate mimicry peptides possibly involved in PBC, we generated 13 different T-cell clones reactive to the human PDC-E2 163-176 peptide following repeated in vitro stimulation of peripheral T lymphocytes with the human PDC-E2 163-176 peptide (native peptide) and tested for the reactivity of these T-cell clones to 30 different mimicry peptides derived from various self- and nonself proteins that have an ExDK-sequence. We found 7 mimicry peptides derived from microbial proteins that can activate at least 1 of these T-cell clones; 7 of 7 T-cell clones from patients with PBC and 2 of 6 T-cell clones from healthy subjects were activated by at least 1 to 6 different mimicry peptides. Two of 6 T-cell clones from healthy subjects were activated by specific mimicry peptides more strongly than by the native peptide, and 2 of 6 T-cell clones from healthy subjects were not activated by any mimicry peptides tested. Thus, the pattern and degree of activation by mimicry peptides differed in each T-cell clone, indicating the presence of a diverse spectrum of autoreactive T cells that are reactive to a single minimal epitope of the human PDC-E2 163-176 peptide.

• Authors: S Shimoda, M Nakamura, H Shigematsu, H Tanimoto, T Gushima, M E Gershwin, H Ishibashi
• Journal: Hepatology (Baltimore, Md.) (Hepatology) Vol. 31 Issue 6 Pg. 1212-6 (Jun 2000) ISSN: 0270-9139 [Print] United States
• PMID: 10827144 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Cytokines
• Immunodominant Epitopes
• Peptide Fragments
• Pyruvate Dehydrogenase Complex
• Dihydrolipoyllysine-Residue Acetyltransferase

Topics

• Cell Division (drug effects)
• Clone Cells (cytology, drug effects, immunology, metabolism)
• Cytokines (biosynthesis)
• Dihydrolipoyllysine-Residue Acetyltransferase
• Humans
• Immunodominant Epitopes
• Liver Cirrhosis, Biliary (immunology)
• Molecular Mimicry
• Peptide Fragments (immunology, pharmacology)
• Pyruvate Dehydrogenase Complex (immunology, pharmacology)
• T-Lymphocytes (classification, cytology, immunology, metabolism)