RESUMO
PIWIL2, a member of PIWI/AGO family, is expressed in germline stem cells and precancerous stem cells, but not in adult somatic cells. PIWIL2 plays an important role in tumor development. It is considered as a cancertestis antigen (CT80). It has been reported that the spliced fragment of PIWIL2, PL2L60, was widely expressed in cancer cell lines. In this study, HLA-A2-restricted epitopes from PL2L60 were predicted by online tools. To improve the activity of the native epitope, a candidate peptide P281 with potent binding affinity was chosen to investigate the modification strategy. A series of aromatic amino acids were introduced to substitute the first residue of P281. Then, we tested the binding affinity and stability of the peptide analogs and their ability to elicit specific immune responses both in vitro and in vivo. Our results indicated that the cytotoxic T lymphocytes (CTLs) induced by [4-Cl-Phe1]P281 could elicit more potent activities than that of P281 and other analogs. The CTLs induced by this analog could lyze target cells in HLA-A2-restricted and antigen-specific manners. [4-Cl-Phe1]P281 also showed the best resistance against degradation in human serum. In conclusion, the introduction of the unnatural amino acid, 4-Cl-Phe, into the first position could enhance the activity of the native epitope to induce cytotoxic T lymphocytes. It might be a good strategy to modify other promising native epitopes. The novel epitopes identified in this study could be used as novel candidates to the immunotherapy of HLA-A2 positive patients with tumors expressing PL2L60.
Assuntos
Proteínas Argonautas/imunologia , Epitopos de Linfócito T/imunologia , Peptídeos/imunologia , Linfócitos T Citotóxicos/imunologia , Processamento Alternativo , Sequência de Aminoácidos , Substituição de Aminoácidos , Animais , Antígenos de Neoplasias/genética , Antígenos de Neoplasias/imunologia , Antígenos de Neoplasias/metabolismo , Proteínas Argonautas/genética , Proteínas Argonautas/metabolismo , Western Blotting , Linhagem Celular , Citotoxicidade Imunológica/imunologia , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/metabolismo , Regulação Neoplásica da Expressão Gênica , Antígeno HLA-A2/imunologia , Células HT29 , Humanos , Interferon gama/imunologia , Interferon gama/metabolismo , Células MCF-7 , Camundongos , Camundongos Transgênicos , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia , Peptídeos/genética , Peptídeos/metabolismo , Fenilalanina/genética , Fenilalanina/imunologia , Fenilalanina/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Linfócitos T Citotóxicos/metabolismoRESUMO
Cytotoxic T lymphocytes (CTLs) play an important role in the immunity of Mycobacterium tuberculosis (Mtb) infection. In the present study, the identification of novel CTL epitopes from efflux pumps, Rv1258c and Rv1410c, was reported. Candidate native peptides and their analogues were predicted with prediction programs. Rv1410c-p510 (TLAPQVEPL) and Rv1410c-p510-1Y9V (YLAPQVEPV) showed potent binding affinity and stability towards HLA-A*0201 molecule. In enzyme-linked immunospot (ELISPOT) assay, the CTLs induced from peripheral blood mononuclear cells (PBMCs) by these peptides could release interferon-γ (IFN-γ) in at least one healthy donor (HLA-A*02(+), PPD(+)). In cytotoxicity assay in vitro and in vivo, the CTLs induced by Rv1410c-p510-1Y9V could specifically lyse peptide-loaded T2 cells. This is the first report to identify CTL epitopes from the efflux pumps of Mtb. The novel epitope identified could serve as candidate to the multivalent peptide vaccine against drug-resistant M. tuberculosis.
Assuntos
Epitopos de Linfócito T/metabolismo , Mycobacterium tuberculosis/imunologia , Linfócitos T Citotóxicos/metabolismo , Vacinas contra a Tuberculose , Tuberculose/imunologia , Transportadores de Cassetes de Ligação de ATP/síntese química , Transportadores de Cassetes de Ligação de ATP/imunologia , Transportadores de Cassetes de Ligação de ATP/metabolismo , Proteínas de Bactérias/síntese química , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/metabolismo , Linhagem Celular , Simulação por Computador , Citotoxicidade Imunológica , ELISPOT , Mapeamento de Epitopos , Epitopos de Linfócito T/imunologia , Antígeno HLA-A2/metabolismo , Humanos , Interferon gama/metabolismo , Ativação Linfocitária , Proteínas de Membrana Transportadoras/síntese química , Proteínas de Membrana Transportadoras/imunologia , Proteínas de Membrana Transportadoras/metabolismo , Mycobacterium tuberculosis/patogenicidade , Fragmentos de Peptídeos/síntese química , Fragmentos de Peptídeos/imunologia , Fragmentos de Peptídeos/metabolismo , Ligação Proteica , Linfócitos T Citotóxicos/imunologia , Linfócitos T Citotóxicos/patologia , Tuberculose/prevenção & controleRESUMO
Cyclooxygenase-2 (COX-2) has been found to be over-expressed in esophageal carcinoma (EC) and it could be considered as a potential tumor-associated antigen (TAA). In the present study, six candidate peptides from COX-2 were firstly predicted and synthesized. Among them, P(479) had the highest affinity and stability toward both HLA-A *0201 and HLA-A *03 molecules and it could significantly promote the IFN-gamma release. The cytotoxic T lymphocytes (CTLs) induced by P(479) could specifically lyse COX-2-expressed EC cell lines, EC-1 (HLA-A3 supertype) and EC-9706 (HLA-A2 supertype). These results suggested that P(479) as a novel broad-spectrum T cell epitope would be very useful in immunotherapy against esophageal carcinoma.