CTL response and protection against P815 tumor challenge in mice immunized with DNA expressing the tumor-specific antigen P815A.
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.
Rosato
A
A
Division of Immunology, Department of Oncology and Surgical Sciences, University of Padova, Italy.
Zambon
A
A
Milan
G
G
Ciminale
V
V
D'Agostino
D M
DM
Macino
B
B
Zanovello
P
P
Collavo
D
D
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
D000951:Antigens, Neoplasm; C076546:tumor rejection antigen P815A, mouse