Optimized DNA vaccines to specifically induce therapeutic CD8 T cell responses against autochthonous breast tumors.
BACKGROUND
Vaccines capable of inducing CD8 T cell responses to antigens expressed by tumor cells are considered as attractive choices for the treatment and prevention of malignant diseases. Our group has previously reported that immunization with synthetic peptide corresponding to a CD8 T cell epitope derived from the rat neu (rNEU) oncogene administered together with a Toll-like receptor agonist as adjuvant, induced immune responses that translated into prophylactic and therapeutic benefit against autochthonous tumors in an animal model of breast cancer (BALB-neuT mice). DNA-based vaccines offer some advantages over peptide vaccines, such as the possibility of including multiple CD8 T cell epitopes in a single construct.


METHODS
Plasmids encoding a fragment of rNEU were designed to elicit CD8 T cell responses but no antibody responses. We evaluated the use of the modified plasmids as DNA vaccines for their ability to generate effective CD8 T cell responses against breast tumors expressing rNEU.


RESULTS
DNA-based vaccines using modified plasmids were very effective in specifically stimulating tumor-reactive CD8 T cell responses. Moreover, vaccination with the modified DNA plasmids resulted in significant anti-tumor effects that were mediated by CD8 T cells without the requirement of generating antibodies to the product of rNEU.


CONCLUSIONS
DNA vaccination is a viable alternative to peptide vaccination to induce potent anti-tumor CD8 T cell responses that provide effective therapeutic benefit. These results bear importance for the design of DNA vaccines for the treatment and prevention of cancer.
Cho
Hyun-Il
HI
Immunology/Immunotherapy Program, H. Lee Moffitt Cancer Center, SRB-2, 12902 Magnolia Drive, Tampa, FL 33612-9416, USA.
Niu
Guilian
G
Bradley
Norma
N
Celis
Esteban
E
D000818:Animals; D000951:Antigens, Neoplasm / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D019496:Cancer Vaccines / Q000276:immunology* / Q000627:therapeutic use; D018275:Carcinoma, Lobular / Q000276:immunology / Q000628:therapy; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000276:immunology* / Q000628:therapy; D051379:Mice; D008807:Mice, Inbred BALB C; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014611:Vaccination; D019444:Vaccines, DNA / Q000276:immunology* / Q000627:therapeutic use
D000951:Antigens, Neoplasm; D019496:Cancer Vaccines; D018984:Epitopes, T-Lymphocyte; D018719:Erb-b2 Receptor Tyrosine Kinases; D019444:Vaccines, DNA