RESUMO
Human CD34(+) progenitor-derived Langerhans-type dendritic cells (LCs) are more potent stimulators of T-cell immunity against tumor and viral antigens in vitro than are monocyte-derived DCs (moDCs). The exact mechanisms have remained elusive until now, however. LCs synthesize the highest amounts of IL-15R-α mRNA and protein, which binds IL-15 for presentation to responder lymphocytes, thereby signaling the phosphorylation of signal transducer and activator of transcription 5 (pSTAT5). LCs electroporated with Wilms tumor 1 (WT1) mRNA achieve sufficiently sustained presentation of antigenic peptides, which together with IL-15R-α/IL-15, break tolerance against WT1 by stimulating robust autologous, WT1-specific cytolytic T-lymphocytes (CTLs). These CTLs develop from healthy persons after only 7 days' stimulation without exogenous cytokines and lyse MHC-restricted tumor targets, which include primary WT1(+) leukemic blasts. In contrast, moDCs require exogenous rhuIL-15 to phosphorylate STAT5 and attain stimulatory capacity comparable to LCs. LCs therefore provide a more potent costimulatory cytokine milieu for T-cell activation than do moDCs, thus accounting for their superior stimulation of MHC-restricted Ag-specific CTLs without need for exogenous cytokines. These data support the use of mRNA-electroporated LCs, or moDCs supplemented with exogenous rhuIL-15, as vaccines for cancer immunotherapy to break tolerance against self-differentiation antigens shared by tumors.
Assuntos
Apresentação de Antígeno , Tolerância Imunológica , Interleucina-15/imunologia , Células de Langerhans/imunologia , Receptores de Interleucina-15/imunologia , Fator de Transcrição STAT5/imunologia , Linfócitos T Citotóxicos/imunologia , Proteínas WT1/imunologia , Crise Blástica/genética , Crise Blástica/imunologia , Crise Blástica/patologia , Crise Blástica/terapia , Vacinas Anticâncer/genética , Vacinas Anticâncer/imunologia , Vacinas Anticâncer/farmacologia , Feminino , Humanos , Interleucina-15/farmacologia , Células de Langerhans/patologia , Leucemia/genética , Leucemia/imunologia , Leucemia/patologia , Leucemia/terapia , Ativação Linfocitária/efeitos dos fármacos , Masculino , Receptores de Interleucina-15/genética , Fator de Transcrição STAT5/genética , Linfócitos T Citotóxicos/patologia , Proteínas WT1/genéticaRESUMO
The TAG-1, TAG-2a, TAG-2b, and TAG-2c cancer/testis genes, known to be expressed in an unusually high percentage of melanoma cell lines, are shown here to be expressed in a variety of tumor lines of diverse histologic type, including cancers of the brain, breast, colon, lung, ovary, pharynx, and tongue. The genes are also expressed in fresh, uncultured melanoma, and ovarian cancer cells. Epitope prediction algorithms were used to identify potential HLA-A1, HLA-A2, HLA-A3, HLA-B7, and HLA-B8 epitopes, and these potential epitopes were tested for their ability to stimulate a peptide-specific cytotoxic T lymphocyte response using lymphocytes from healthy donors. Two HLA-A2-restricted epitopes (SLGWLFLLL and LLLRLECNV) were identified using this approach. Cytotoxic T lymphocytes specific for each of these peptides were capable of recognizing tumor cells expressing both the corresponding class I major histocompatibility complex encoded molecule and the TAG genes. These results indicate that TAG-derived peptides may be good components of a therapeutic vaccine designed to target melanoma and a variety of epithelial cell-derived malignancies.
Assuntos
Antígenos de Neoplasias/imunologia , Epitopos de Linfócito T/imunologia , Antígeno HLA-A2/imunologia , Neoplasias/imunologia , Sequência de Aminoácidos , Antígenos de Neoplasias/genética , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/imunologia , Neoplasias Encefálicas/patologia , Neoplasias da Mama/genética , Neoplasias da Mama/imunologia , Neoplasias da Mama/patologia , Moléculas de Adesão Celular Neuronais/genética , Moléculas de Adesão Celular Neuronais/imunologia , Linhagem Celular Tumoral , Neoplasias do Colo/genética , Neoplasias do Colo/imunologia , Neoplasias do Colo/patologia , Contactina 2 , Testes Imunológicos de Citotoxicidade , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Epitopos de Linfócito T/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Antígeno HLA-A2/genética , Antígenos de Histocompatibilidade Classe I/genética , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/patologia , Neoplasias/genética , Neoplasias/patologia , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/imunologia , Neoplasias Ovarianas/patologia , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/imunologia , Neoplasias Faríngeas/genética , Neoplasias Faríngeas/imunologia , Neoplasias Faríngeas/patologia , Linfócitos T Citotóxicos/imunologia , Neoplasias da Língua/genética , Neoplasias da Língua/imunologia , Neoplasias da Língua/patologia , Neoplasias do Colo do Útero/genética , Neoplasias do Colo do Útero/imunologia , Neoplasias do Colo do Útero/patologiaRESUMO
PURPOSE: The efficient identification of peptide antigens recognized by ovarian cancer-specific cytotoxic T lymphocytes (CTL) requires the use of well-characterized ovarian cancer cell lines. To develop such a panel of cell lines, 11 ovarian cancer cell lines were characterized for the expression of class I and class II major histocompatibility complex (MHC)-encoded molecules, 15 tumor antigens, and immunosuppressive cytokines [transforming growth factor beta (TGF-beta) and IL-10]. METHODS: Class I MHC gene expression was determined by polymerase chain reaction (PCR), and class I and class II MHC protein expression was determined by flow cytometry. Tumor antigen expression was determined by a combination of polymerase chain reaction (PCR) and flow cytometry. Cytokine expression was determined by ELISA. RESULTS: Each of the ovarian cancer cell lines expresses cytokeratins, although each cell line does not express the same cytokeratins. One of the lines expresses CD90, which is associated with a fibroblast lineage. Each of the cell lines expresses low to moderate amounts of class I MHC molecules, and several of them express low to moderate amounts of class II MHC molecules. Using a combination of PCR and flow cytometry, it was determined that each cell line expressed between six and thirteen of fifteen antigens tested. Little to no TGF-beta3 was produced by any of the cell lines, TGF-beta1 was produced by three of the cell lines, TGF-beta2 was produced by all of the cell lines, with four of the cell lines producing large amounts of the latent form of the molecule, and IL-10 was produced by one of the cell lines. CONCLUSIONS: Each of the 11 ovarian cancer lines is characterized by a unique expression pattern of epithelial/fibroblast markers, MHC molecules, tumor antigens, and immunosuppressive cytokines. Knowledge of these unique expression patterns will increase the usefulness of these cell lines in identifying the antigens recognized by ovarian cancer-specific CTL.