title: Immune responses and therapeutic antitumor effects of an experimental DNA vaccine encoding human papillomavirus type 16 oncoproteins genetically fused to herpesvirus glycoprotein D.
abstract: Recombinant adenovirus or DNA vaccines encoding herpes simplex virus type 1 (HSV-1) glycoprotein D (gD) genetically fused to human papillomavirus type 16 (HPV-16) oncoproteins (E5, E6, and E7) induce antigen-specific CD8(+) T-cell responses and confer preventive resistance to transplantable murine tumor cells (TC-1 cells). In the present report, we characterized some previously uncovered aspects concerning the induction of CD8(+) T-cell responses and the therapeutic anticancer effects achieved in C57BL/6 mice immunized with pgD-E7E6E5 previously challenged with TC-1 cells. Concerning the characterization of the immune responses elicited in mice vaccinated with pgD-E7E6E5, we determined the effect of the CD4(+) T-cell requirement, longevity, and dose-dependent activation on the E7-specific CD8(+) T-cell responses. In addition, we determined the priming/boosting properties of pgD-E7E6E5 when used in combination with a recombinant serotype 68 adenovirus (AdC68) vector encoding the same chimeric antigen. Mice challenged with TC-1 cells and then immunized with three doses of pgD-E7E6E5 elicited CD8(+) T-cell responses, measured by intracellular gamma interferon (IFN-γ) and CD107a accumulation, to the three HPV-16 oncoproteins and displayed in vivo antigen-specific cytolytic activity, as demonstrated with carboxyfluorescein diacetate succinimidyl ester (CFSE)-labeled target cells pulsed with oligopeptides corresponding to the H-2D(b)-restricted immunodominant epitopes of the E7, E6, or E5 oncoprotein. Up to 70% of the mice challenged with 5 × 10(5) TC-1 cells and immunized with pgD-E7E6E5 controlled tumor development even after 3 days of tumor cell challenge. In addition, coadministration of pgD-E7E6E5 with DNA vectors encoding pGM-CSF or interleukin-12 (IL-12) enhanced the therapeutic antitumor effects for all mice challenged with TC-1 cells. In conclusion, the present results expand our previous knowledge on the immune modulation properties of the pgD-E7E6E5 vector and demonstrate, for the first time, the strong antitumor effects of the DNA vaccine, raising promising perspectives regarding the development of immunotherapeutic reagents for the control of HPV-16-associated tumors.
authors.affiliation: Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 1374, Cidade Universitária, São Paulo, Brazil.
authors.forename: Mariana O
authors.initials: MO
authors.lastname: Diniz
authors.forename: Marcio O
authors.initials: MO
authors.lastname: Lasaro
authors.forename: Hildegund C
authors.initials: HC
authors.lastname: Ertl
authors.forename: Luís C S
authors.initials: LC
authors.lastname: Ferreira
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D019496:Cancer Vaccines / Q000008:administration & dosage / Q000276:immunology*; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D052162:Human papillomavirus 16 / Q000235:genetics / Q000276:immunology*; D007117:Immunization, Secondary / Q000379:methods; D007371:Interferon-gamma / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D009374:Neoplasms, Experimental / Q000276:immunology / Q000517:prevention & control*; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000276:immunology*; D053918:Papillomavirus Vaccines / Q000235:genetics / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000276:immunology; D013997:Time Factors; D014611:Vaccination / Q000379:methods; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology*; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology*
chemical_list: D019496:Cancer Vaccines; D009856:Oncogene Proteins, Viral; D053918:Papillomavirus Vaccines; D011993:Recombinant Fusion Proteins; D019444:Vaccines, DNA; D014759:Viral Envelope Proteins; C039447:glycoprotein D, Human herpesvirus 1; D007371:Interferon-gamma