TAP expression level in tumor cells defines the nature and processing of MHC class I peptides for recognition by tumor-specific cytotoxic T lymphocytes.
| Autor: | El Hage F; Chimie et Sciences de la Vie et de la Terre, Université Saint-Esprit de Kaslik, Jounieh, Lebanon., Durgeau A, Mami-Chouaib F |
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| Jazyk: | angličtina |
| Zdroj: | Annals of the New York Academy of Sciences [Ann N Y Acad Sci] 2013 Apr; Vol. 1283, pp. 75-80. Date of Electronic Publication: 2013 Jan 09. |
| DOI: | 10.1111/j.1749-6632.2012.06777.x |
| Abstrakt: | We identified that the antigen preprocalcitonin (ppCT) is recognized on a human lung carcinoma by a cytotoxic T lymphocyte clone derived from autologous tumor-infiltrating lymphocytes. The antigenic peptide ppCT(16-25) is encoded by the gene calcitonin-related polypeptide alpha (CALCA), which codes for CT and is overexpressed in several lung carcinomas compared with normal tissues. The ppCT peptide is derived from the C-terminal region of the signal peptide and is processed independently of proteasomes and the transporter associated with antigen processing (TAP)1/TAP2 heterodimeric complexes. Instead, processing occurs within the endoplasmic reticulum by a novel mechanism involving signal pepsidase (SP) and signal peptide peptidase (SPP). Although lung cancer cells bearing the ppCT(16-25) epitope displayed low levels of TAP, restoration of TAP expression by interferon (IFN)-γ treatment or by TAP1/TAP2 gene transfer inhibited ppCT antigen presentation. Thus, the ppCT(16-25) human tumor epitope requires low TAP expression for efficient presentation. These results indicate that emerging SP-generated peptides represent alternative T cell targets that permit cytotoxic T lymphocytes to destroy TAP-impaired tumors, a process that helps to overcome tumor escape from CD8(+) T cell immunity. Additionally, our data suggest that ppCT is a promising candidate for cancer immunotherapy. (© 2013 The New York Academy of Sciences.) |
| Databáze: | MEDLINE |
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