Study on Immune Response Induced by HPV18-E2 DNA Vaccine Combined with IL-12

Objective To study the effectiveness of human papillomavirus type 18 E2 gene(HPV18-E2) vaccine and interleukin-12(IL-12) on their immune effects. Methods Thirty-five Balb/c female mice aged 6 to 8-week-old were randomly divided into five groups,namely,PBS group,pcDNA3.1(+) empty plasmid group,pcDNA3.1(+) / E2 group,pcDNA3.1(+) / IL-12 group,and pcDNA3.1(+) / E2 + pcDNA3.1(+) / IL-12 group(each n=7).The mice were given intramuscular injection of DNA vaccines at 2-week interval for four times,and 100mg/times.The tails were cut to draw blood at the 0,2,4,6 weeks,and then the mice were executed by eyeball blood letting at the 8 weeks.ELISA was used for the quantitative detection of the specific IgG antibody in the sera of Balb/c mice and the cytokine IFN-γ and IL4 in mice spleen lymphocyte culture medium after stimulating by HPV18-E2.The proliferation response of spleen cells was detected by MTT assay. Results After 8 weeks immunization,antibody IgG A in pcDNA3.1(+) / E2 vaccine group and pcDNA3.1(+) / E2 + pcDNA3.1(+) / IL-12 vaccine group was significantly increased as compared with that of control group,and the difference was statistically significant(P0.01).IFN-γ and IL-4 levels of mice spleen lymphocyte culture supernatant in pcDNA3.1(+) / E2 group and pcDNA3.1(+) / E2 + pcDNA3.1(+) / IL-12 group were significantly higher than those of the other control groups,and the difference was statistically significant(P0.01).The spleen lymphopoiesis activeness of pcDNA3.1(+)/E2+pcDNA3.1(+)/IL-12 group was significantly enhanced as compared with the pcDNA3.1(+)/E2 group,no statistically significant difference was found between them(P0.05),but as compared with the other control groups,there were statistically significant differences(P 0.01). Conclusions pcDNA3.1(+) / E2 + pcDNA3.1(+) / IL-12 DNA vaccine combined with immunization mice can effectively induce cell-mediated immunity and humoral immune responses,their capabilities of inducing immune response might be more stronger than that of pcDNA3.1(+)/E2 DNA vaccine.