Identification of an epitope from the epithelial cell adhesion molecule eliciting HLA-A*2402-restricted cytotoxic T-lymphocyte responses.
Because the epithelial cell adhesion molecule (Ep-CAM) is expressed in almost all carcinomas and human leucocyte antigen (HLA)-A*2402 is the most common allele in many ethnic groups, including Japanese, the identification of peptide sequences, which elicit HLA-A*2402-restricted Ep-CAM-specific cytotoxic T-lymphocyte (CTL) responses, would facilitate specific immunotherapy for various histological types of carcinomas. An epitope was identified through the following steps: (i) computer-based epitope prediction from the amino acid sequence of Ep-CAM, (ii) major histocompatibility complex (MHC) stabilization assay to determine the affinity of the predicted peptide with HLA-A*2402 molecules, (iii) stimulation of CD8+ T cells with peptide-pulsed dendritic cells and (iv) testing the CTL specificity by means of enzyme-linked immunospot (ELISPOT) assays, CTL assays and MHC/peptide-tetramer staining. Peripheral CD8+ T cells of four of five healthy donors after three rounds of stimulation with the peptide Ep-CAM173-181 (RYQLDPKFI) secreted interferon-gamma in ELISPOT assays when exposed to the peptide. A CTL clone specific to the peptide efficiently lysed Ep-CAM-expressing cancer cell lines in an HLA-A*2402-restricted fashion. Endogenous processing and presentation of the peptide in a lung cancer cell line were confirmed by means of cold target inhibition assays. The CTL clone was also lytic to normal bronchial epithelial cells but to a lesser extent at low effector: target ratios. All these data suggest that the peptide-specific CTL responses may play some roles both in anti-cancer and autoimmune reactions. The peptide should prove useful to study anti-Ep-CAM CTL responses among population possessing HLA-A*2402.
Tajima
K
K
Division of Immunology, Aichi Cancer Center Research Institute, Nagoya, Japan.
Demachi
A
A
Ito
Y
Y
Nishida
K
K
Akatsuka
Y
Y
Tsujimura
K
K
Kuwano
H
H
Mitsudomi
T
T
Takahashi
T
T
Kuzushima
K
K
D014408:Biomarkers, Tumor / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002448:Cell Adhesion; D003110:Colonic Neoplasms / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D003713:Dendritic Cells; D004847:Epithelial Cells / Q000276:immunology*; D000939:Epitopes / Q000276:immunology*; D015234:HLA-A Antigens / Q000276:immunology*; D059871:HLA-A24 Antigen; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D008175:Lung Neoplasms / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D010446:Peptide Fragments / Q000276:immunology; D013274:Stomach Neoplasms / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014407:Tumor Cells, Cultured
D014408:Biomarkers, Tumor; D000939:Epitopes; D015234:HLA-A Antigens; C438506:HLA-A*24:02 antigen; D059871:HLA-A24 Antigen; D010446:Peptide Fragments; D007371:Interferon-gamma