Immune Response Induced By DNA Vaccine Co-encoding Classical Swine Fever Virus E2 And GM-CSF In Mice

Classical swine fever is highly contagious viral disease with high mortality andcauses large economic losses of swine world-wide. It is classified as the 1st animaldisease in China. In the 1960s. Chinese vaccine strain (C-strain) plays crucial role inthe process of prevention against CSF and arrests the prevalence of CSF in large scalein China. However, in recent years CSF appears sporadic endemic throughout China.Traditional vaccines could not effectively control its endemic. Thus, it is essential todevelop more safe and effective CSF vaccines. The aim of this study was to testimmune response in mice intramuscularly and mucosal immunized with EukaryoticExpression Vector co-encoding E2 and GM-CSF.1. Immune response induced by DNA vaccine co-encoding Classical Swine FeverVirus E2 and GM-CSF in mice: To study effect of GM-CSF on immune response inmice elicited by immunization of DNA vaccine co-encoding CSFV E2 and GM-CSF.CSFV E2 and GM-CSF were amplified by PCR. And then inserted into pcDNA3.0 toconstruct DNA Vaccines: pcE2, pcE2-GF and pcGF. 50 female mice were randomlydivided into 5 groups, 10 each. Group A, B were immunized with pcE2 and pcE2-GFand group B,C and D are controls, immunized with pcDNA3.0,pcGF andphysiological saline respectively, at weeks 0,2,4 sera were collected before everyimmunization and 2 weeks after final immunization. Serum lgG were detected byELISA. Spleen lymphocyte cells of mice were collected 2 weeks after finalimmunization. Proliferation activity of spleen lymphocytes was detected by MTTassay. Results showed that compared with control groups, level of IgG in seraincreased, and proliferation activity of spleen lymphocytes was increased. Furthermore,IgG level in sera and proliferation activity of spleen lymphocytes of group B arehigher than that of group A. In conclusion, GM-CSF can increase the level of immuneresponse in mice induced by immunization with DNA vaccine of Classical SwineFever Virus E2.2. Mucosal immune response in mice immunized with Classical Swine FeverVirus DNA vaccines: In order to probe the mucosal immune response in mice induced by Classical Swine Fever Virus DNA vaccines, 50 female mice were randomly dividedinto 5 groups, 10 each. Group A, B were immunized with pcE2 and pcE2-GF andgroup B,C and D are controls, immunized with pcDNA3.0,pcGF and normal salinerespectively. Group A, B were intranasal immunized with 50μg pcE2 and 50μgpcE2-GF. Control group B,C and D were intranasal immunized with 50μgpcDNA3.0,50μg pcGF and 20μl physiological saline respectively at 0-2-4th week.IMD was 5％Span+1％Glycerine+50μg DNA Plasmid per mouse and times. Theimmune bulk volume is 20μl per mouse and times. Sera and fresh fecal were collectedbefore every immunization and 2 weeks after the final immunization. Levels ofspecific fecal sIgA and serum lgG and IgA were detected by ELISA. The resultsshowed that the systemic and mucosal immune responses were induced in both groupA and group B. The level of antibody in serum and fecal gradually increased afterbooster inoculation. Furthermore the level of antibody in group B (immunized withpcE2-GF) was significantly higher than that in group A (immunized with CSFV E2DNA).GM-CSF could improve the immune response in mice induced by CSFV E2 DNAvaccine. The systemic and mucosal immune response induced by intranasalvaccination with CSFV E2 DNA vaccine and DNA vaccine co-encoding CSFV E2 andGM-CSF in mice. GM-CSF could improve the mucosal immune response. Thisresearch proved a new idea for CSF genetically engineering vaccine regardingadjuvant and mucosal immunization.