Evaluation of Therapeutic Potency of Human Papillomavirus-16 E7 Dna Vaccine Alone and With Interleukin-18 As a Genetic Adjuvant Publisher



Pourhossein B¹ ; Ghaemi A² ; Fazeli M² ; Azadmanesh K² ; Mahmoodi M³ ; Mirshafiey A⁴ ; Shahmahmoodi S^{1, 5}
Source: Scientia Medica Published:2018

Abstract

AIMS: Despite the existence of effective preventive vaccines for human papillomavirus (HPV), therapeutic vaccines that trigger cell-mediated immune responses are required to treat established infections and malignancies. The aim of this study was to evaluate the therapeutic potency of HPV-16 E7 deoxyribonucleic acid (DNA) vaccine alone and with interleukin (IL)-18. METHODS: In vitro expressions of IL-18 were performed on human embryonic kidney 293 cells and confirmed it by Western blotting methods. DNA vaccine was available from a previous study. A total of 45 female C57BL/6 mice divided into five groups (DNA vaccine, DNA vaccine adjuvanted with IL-18, pcDNA3.1, and phosphate buffer saline) were inoculated with murine tissue culture-1 cell line of HPV related carcinoma, expressing HPV-16 E6/E7 antigens. They were then immunized subcutaneously twice at a seven-day interval. The antitumor and antigen specific-cellular immunity were assessed by lymphocyte proliferation (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide: MTT) assay, lactate dehydrogenase release assay, IL-4 assay and interferon-gamma (IFN-γ) assay. Tumor size was followed for 62 days. RESULTS: MTT assay, which measures the lymphocyte proliferation in response to the specific antigen, increased in the co-administration and the DNA vaccine groups as compared to control and genetic adjuvant groups (p<0.001). The mice immunized with the co-administration generated significantly more IFN-γ and IL-4 than other immunized mice (p<0.001). Reduction of the tumor size in the co-administration and the DNA vaccine groups was significantly more pronounced than in the control and genetic adjuvant groups (p<0.001), but no statistically significant difference between DNA vaccine and co-administration groups (p=0.15) occurred. CONCLUSIONS: IL-18 as a genetic adjuvant and E7 DNA vaccine alone enhanced immune responses in mouse model systems against cervical cancer. However, using of IL-18 as a genetic adjuvant with E7 DNA vaccine had no significant synergistic effect on the immune responses in vivo. © Editora Universitaria da PUCRS. All rights reserved.