To assess the therapeutic effects of vaccination, one first challenges mice with antigen-expressing tumors. Second, some mice are immunized with a candidate vaccine while unimmunized mice are used as controls. Finally, the antitumor effect in immunized subjects and unimmunized controls is evaluated and compared.

Vaccination with E7-HSP70 DNA eradicates pre-existing TC-1 tumor cells. Each mouse was initially challenged with 2 x 104 TC-1 cells s.c., followed by DNA vaccination with empty plasmid (pcDNA3), HSP70 DNA (HSP), E7 DNA (E7), or E7-HSP70 DNA (E7/HSP) via a gene gun. The mice were monitored for evidence of tumor growth by palpation and inspection twice a week. A, each mouse received 2 µg of DNA vaccine 3 days and 10 days after the tumor challenge. B, each mouse received 2 µg of DNA vaccine only 3 days after the tumor challenge. No further booster was given. (Enhancement of DNA Vaccine Potency by Linkage of Antigen Gene to an HSP70 Gene)

The Lung Metastasis Model to Assess the Therapeutic Effect of a Cancer Vaccine

Representative gross pictures of the lung tumors in each vaccinated group. After in vivo tumor treatment experiments against preexisting metastatic TC-1 tumor cells, there are multiple grossly visible lung tumors in unvaccinated control mice and mice vaccinated with FL, wild-type E7 DNA, or FL mixed with E7 DNA. The lung tumors in the FL-E7 vaccinated group cannot be seen at the magnification provided in this figure. (Enhancement of DNA Vaccine Potency by Linkage of Antigen Gene to a Gene Encoding the Extracellular Domain of Fms-like Tyrosine Kinase 3-Ligand)