| Project/Area Number |
10557083
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Dermatology
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| Research Institution | Keio University |
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Principal Investigator |
KAWAKAMI Yutaka Keio Univ. School of Medicine, Professor, 医学部, 教授 (50161287)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIKAWA Takeji Keio Univ. School of Medicine, Professor, 医学部, 教授 (50051579)
SUZUKI Yuriko Keio Univ. School of Medicine, Instructor, 医学部, 助手 (40255435)
IKEDA Hideyuki Keio Univ. School of Medicine, Assistant Professor, 医学部, 専任講師 (40301494)
YAMAMOTO Akifumi Division of Dermatology, National Cancer Center, Chief, 中央病院, 医長(研究職)
SAIDA Toshiaki Shinshu Univ. School of Medicine, Professor, 医学部, 教授 (10010381)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥13,600,000 (Direct Cost: ¥13,600,000)
Fiscal Year 1999: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1998: ¥10,600,000 (Direct Cost: ¥10,600,000)
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| Keywords | Melanoma / Tumor antigens / T cells / cDNA cloning / Melanosomal proteins / P-loop / Mutation / Immunotherapy / 突然変異 / チロシナーゼ / gp100 / HLA |
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| Research Abstract |
A total of 123 tumor infiltrating T lymphocytes (TIL) established from patients with metastatic melanoma was screened for identification of T cells that might recognize novel melanoma antigens or epitopes in previously identified antigens. Using 5 TIL that possibly recognized new antigens in the context of HLA-A 1, -A2 or -A3, antigens were isolated by cDNA expression cloning. New epitopes of the previously identified antigens (1 HLA-A1 binding tyrosinase peptide, 2 HLA-A2 binding gp100 peptides, 1 HLA-A3 binding gp100 peptide) were identified. Replacement of either cysteine to β-amino butyric acid in the gp100 peptide, RLPRIFCSC, enhanced the T cell recognition, suggesting that unoxidized cysteines were presented on the tumor cell surface. Since oxidation of the cysteines may easily occur in the synthetic peptides in in vitro culture, the modification of cysteines may have important implications for the development of peptide based vaccines. Using another HLA-A 1 restricted T cells, 8B6 antigen was isolated. The cDNA for the ubiquitously expressed 8B6 encoded an uncharacterized protein with a phosphate binding loop (P-loop) motif. A mutation was found in the P-loop of the 8B6 cDNA obtained from the 1362mel melanoma cell line, and the mutated 8B6 lost GTP binding ability. A T cell epitope with a glutamic acid encoded by the mutated sequence was identified, and the wild type peptide was not recognized by TIL 1362, suggesting that this T cell response was autologous tumor specific. Since many of the mutated antigens previously isolated with CD8+ T cells, including β-catenin, CDK4 and caspase 8, appeared to be involved in tumorigenesis, the mutated 8B6 may also be involved in the generation of melanoma possibly through inability to bind GTP. These newly identified melanoma antigens may be useful for development of immunotherapy as well as for understanding the biology of melanoma.
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