title: CTL response and protection against P815 tumor challenge in mice immunized with DNA expressing the tumor-specific antigen P815A.
abstract: A DNA immunization approach was used to induce an immune response against the tumor-specific antigen P815A in DBA/2 mice. The P1A gene, which encodes the P815A antigen, was modified by the addition of a short sequence coding for a tag epitope recognized by the monoclonal antibody AU1, and cloned into the eukaryotic expression vector pBKCMV, resulting in plasmid pBKCMV-P1A. L1210 cells stably transfected with pBKCMV-P1A expressed P1A mRNA and were lysed by the syngeneic P815A-specific cytotoxic clone CTL-P1:5, thus confirming that the tag-modified P1A protein underwent correct processing and presentation. A single intramuscular injection of 100 microg of pBKCMV-P1A induced the expression of P1A mRNA for at least 4 months. Eighty percent of DBA/2 mice injected three times with 100 microg of pBKCMV-P1A generated cytotoxic T lymphocytes (CTL) that lysed P815 tumor cells, whereas mock-inoculated animals failed to show any cytotoxicity. Moreover, experiments designed to evaluate the protection of pBKCMV-P1A-immunized mice against a lethal challenge with P815 tumor cells showed that 6 of 10 immunized mice rejected the tumor, and 2 mice showed prolonged survival compared to control animals.
authors.affiliation: Division of Immunology, Department of Oncology and Surgical Sciences, University of Padova, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Rosato
authors.forename: A
authors.initials: A
authors.lastname: Zambon
authors.forename: G
authors.initials: G
authors.lastname: Milan
authors.forename: V
authors.initials: V
authors.lastname: Ciminale
authors.forename: D M
authors.initials: DM
authors.lastname: D'Agostino
authors.forename: B
authors.initials: B
authors.lastname: Macino
authors.forename: P
authors.initials: P
authors.lastname: Zanovello
authors.forename: D
authors.initials: D
authors.lastname: Collavo
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics* / Q000276:immunology*; D017690:Cell Transplantation; D005260:Female; D006801:Humans; D007114:Immunization / Q000379:methods*; D051379:Mice; D008811:Mice, Inbred DBA; D009369:Neoplasms / Q000235:genetics / Q000276:immunology / Q000517:prevention & control*; D010957:Plasmids / Q000235:genetics / Q000494:pharmacology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014407:Tumor Cells, Cultured
chemical_list: D000951:Antigens, Neoplasm; C076546:tumor rejection antigen P815A, mouse