Identification of an antigenic epitope for helper T lymphocytes from carcinoembryonic antigen
| Autor: | Kobayashi, H., Omiya, R., Ruiz, M., Huarte, E., Sarobe, P., Juan J Lasarte, Herraiz, M., Sangro, B., Prieto, J., Borras-Cuesta, F., Celis, E. |
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| Zdroj: | Publons CIÊNCIAVITAE Europe PubMed Central Dadun. Depósito Académico Digital de la Universidad de Navarra instname Scopus-Elsevier ResearcherID |
| Popis: | PURPOSE: The product of the carcinoembryonic antigen (CEA) gene is an attractive candidate for T-cell-based immunotherapy because it is frequently expressed in epithelial solid carcinomas. Although many CEA peptide epitopes capable of stimulating CTLs have been identified, no MHC class II-restricted T helper epitope has yet been reported. Experimental Design: The amino acid sequence of CEA was examined for the presence of potential T helper epitopes, and candidate peptides were used to stimulate in vitro T-cell responses. RESULTS: We describe here that using an algorithm to identify promiscuous helper T-cell epitopes, a peptide of CEA occupying residue positions 653 to 667 (CEA(653-667)), was effective in inducing in vitro T helper responses in the context of the HLA-DR4, HLA-DR7, and HLA-DR 9 alleles. Most significantly, some of the peptide-reactive helper T lymphocytes were also capable of recognizing naturally processed antigen in the form of recombinant CEA protein or cell lysates from tumors that express CEA. Interestingly, the newly identified helper T-cell epitope was found to overlap with a previously described HLA-A24-restricted CTL epitope, CEA(652-660), which could facilitate the development of a therapeutic vaccine capable of eliciting both CTL and T helper responses in patients suffering from epithelial carcinomas. CONCLUSION: These results indicate that T helper lymphocytes are capable of recognizing CEA as a tumor antigen and that epitope CEA(653-667) could be used for immunotherapy against tumors expressing CEA. |
| Databáze: | OpenAIRE |
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