| Project/Area Number |
08457155
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
内科学一般
|
|---|
| Research Institution | KYUSHU UNIVERSITY |
|---|
Principal Investigator |
ISHIBASHI Hiromi KYUSHU UNIVERSITY,FACULTY OF MEDICINE,ASSOCIATE PROFESSOR, 医学部, 助教授 (80127969)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
NISHIMURA Yasuharu KUMAMOTO UNIVERSITY,FACULTY OF MEDICINE,PROFESSOR, 医学部, 教授 (10156119)
HAYASHIDA Kazuhiro KYUSHU UNIVERSITY,FACULTY OF MEDICINE,INSTRUCTOR, 医学部, 助手 (60180981)
NAKAMURA Minoru KYUSHU UNIVERSITY,FACULTY OF MEDICINE,INSTRUCTOR, 医学部, 助手 (40217906)
|
|---|
| Project Period (FY) |
1996 – 1997
|
| Project Status |
Completed (Fiscal Year 1997)
|
| Budget Amount *help |
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 1997: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1996: ¥3,800,000 (Direct Cost: ¥3,800,000)
|
|---|
| Keywords | Primary biliary cirrhosis / Autoimmune disease / Immune regulation / T cell / T cell receptor / T cell epitope / Molecular mimicry / Immune response / HLA |
|---|
| Research Abstract |
1.Mapping of B cell epitope of mitochondrial antigen.
Using anti-mitochondrial antibody obtained from the oatient with primary biliary cirrhosis (PBC), we performed epitope mapping of a major mitochondrial antigen, E2 component of pyruvate dehydrogenase complex (PDC-E2). The epitopes are mapped in the regions around lipoic acid-bound lysine in the outer and innner lypoil domains. Each Asp of the N-terminal side is important to bind antibody. Lypoic acid did not influence immunoreactivity with the antibody.
2.Cloning of T cell specific for mitochondrial antigen epitope mapping.
We established six T cell clones specific for PDC-E2 peptides from four different patients with PBC using 33 different peptides of 17-20 amino acid residues corresponding to human PDC-E2 as stimulating antigens (Ags). The minimal T cell of these six T cell clones were all mapped to the same region of the PDC-E2 peptide 163-176 (GDLLAEIETDKATI). The common essential amino acids of this epitope for these T cell clones
… More
were E,D and K at positions 170,172 and 173, respectively. One T cell clone cross-reacted to exogenous Ags such as E.coli PDC-E2 peptide which has an EXDK sequence. This is the definite demonsration of the presence of molecular mimicry at the T cell clonal level in human autoimmune diseases.
T cell receptor
We found that frequency of the T cells reactive to the human PDC-E2 163-176 peptide is significantly increased in the peripheral blood of patients with PBC as compared to healthy subjects. We also confirmed that these T cells were all restricted with HLA-DRB4^<**>01 (DR53). These results together with the evidence that the immunodominant B cell epitope overlaps with the human T cell epitope of the PDC-E2 antigen indicate that the T cells reactive to this epitope are closely associated with the pathogenesis of PBC.The Vbeta-and the Jbeta-gene usages were diverse among the T cell clones (Vbeta11-Lbeta1.4, Vbeta8-Jb1.2, Vbeta12-Jb2.1, Vbeta10-Jbeta1.5 and Vbeta20-Jbeta2.1). By contrast, in the third complementarity determining region (CDR3), G was frequently found and GXG or GXS motif was identified in all T cell clones. Moreover, RGXG motif was found in three clones generated from two patients.These results indicate that the T cells may recognize the ligand (the human PDC-E2 163-176 peptide/HLA-DR53 complex) using the limited motif in the CDR3 region and that the design of CDR3-specific immunotherapy wouled be possible using these motifs. Less
|
