title: Combined immunization with DNA and transduced tumor cells expressing mouse GM-CSF or IL-2.
abstract: A combination of different types of vaccines usually induces enhanced immune responses in comparison to immunization with single vaccines. The highest efficacy of a heterologous prime-boost strategy is mostly achieved after priming with a DNA vaccine and boosting with a recombinant virus or a protein vaccine. The aim of this study was to determine whether the combination of a DNA and cellular vaccine elicits stronger antitumor immune responses than vaccines used alone and to find out whether the efficacy of this combined immunization depends on the sequence in which the vaccines were applied. We utilized experimental vaccines that proved to be partially effective in protection against mouse tumor cells representing models of human papillomavirus-induced malignancies. The fusion gene Sig/E7GGG/LAMP-1, inoculated via a gene gun, was used for DNA immunization. As cellular vaccines, HPV16 E6/E7 and H-ras transformed B9 or 181 cells transduced with the gene coding for GM-CSF or IL-2, respectively, were applied. In both preventive and therapeutic immunizations, inoculation first with the DNA vaccine followed by application of a cellular vaccine induced the best protection from tumor growth. These results were confirmed by detection of immune reactions with in vitro tests. We failed to enhance immune reactions by utilization of an equivalent mix of B9 and 181 cells, but the addition of the second DNA-vaccine dose applied simultaneously with a cellular-vaccine boost moderately increased antitumor response. Our findings suggest the benefit of the heterologous prime-boost strategy based on combination of a DNA vaccine with a cellular vaccine and importance of sequence in which the vaccines are administered.
authors.affiliation: Department of Experimental Virology, Institute of Hematology and Blood Transfusion, U Nemocnice 1, 128 00 Prague 2, Czech Republic.
authors.forename: Simon
authors.initials: S
authors.lastname: Rittich
authors.forename: Martina
authors.initials: M
authors.lastname: Duskova
authors.forename: Jana
authors.initials: J
authors.lastname: Mackova
authors.forename: Dana
authors.initials: D
authors.lastname: Pokorna
authors.forename: Pavel
authors.initials: P
authors.lastname: Jinoch
authors.forename: Michal
authors.initials: M
authors.lastname: Smahel
mesh_terms: D000818:Animals; D019496:Cancer Vaccines / Q000008:administration & dosage / Q000627:therapeutic use*; D003602:Cytotoxicity, Immunologic; D011905:Genes, ras; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics*; D007114:Immunization; D007117:Immunization, Secondary; D007376:Interleukin-2 / Q000235:genetics*; D008175:Lung Neoplasms / Q000517:prevention & control / Q000556:secondary; D051379:Mice; D008810:Mice, Inbred C57BL; D009369:Neoplasms / Q000276:immunology / Q000628:therapy*; D009856:Oncogene Proteins, Viral / Q000008:administration & dosage; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage; D012097:Repressor Proteins / Q000008:administration & dosage; D014161:Transduction, Genetic; D014407:Tumor Cells, Cultured; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D019496:Cancer Vaccines; C068651:E6 protein, Human papillomavirus type 16; D007376:Interleukin-2; D009856:Oncogene Proteins, Viral; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D019444:Vaccines, DNA; D016178:Granulocyte-Macrophage Colony-Stimulating Factor