Immune Responses To Hbv Surface Protein Using Dna Prime And Prome And Protein Boost Stuategy In Balb/c Mice

Background Hepatitis B virus (HBV) infection is a world wide public health problemof major concern. HBV infection may lead to chronic liver disease, including chronichepatitis, cirrhosis and hepatocellular carcinoma (HCC). Vaccination is the mosteffective measure to control and prevent hepatitis B, which are composed of HBVsurface antigen mainly. Anti-HBs could be produced by 90%-95% of the people beingvaccined. However, the Anti-HBs can not being induced in 5%-10% of the peoplevaccined even they were vaccined three doses. The specific cellular and humoralimmunity could not be induced in the patient with HBV infection after vaccinationbecause immunological tolerance to HBsAg, especially the inferior special cellularimmunity . Superiority of DNA vaccine is gradually accepted since the DNA vaccineappeared and acknowledged in prevention and treatment of the infection such asvirus, intracellular bacterium and parasite infection. The HBsAg DNA vaccine couldinduce the special cellular immunity in the patients of Hepatitis, and have thepotentiality therapeutical effect. Whereas, the immunocompetence is weak whenbeing used in the macrofauna .Lots of measures to improve the immunocompetence were studied in the pastseveral years. The the heterologous prime-boost regimen is one of immune strategy.Researches has shown that strong sepcial cellular immnity could be induced by usingthe heterologous prime–boost regimen which has shown a good applying prospect.A novel HBsAg DNA vaccine pSW3891/MHBs/adr ( shoreten for adr )constructed in our former study could induce strong antibody response in the Balb/cmice. The aim of this study is to observe the effect on the immune response to HBV surface protein vaccine using DNA prime and HBV protein boost strategy in Balb/cmice.ObjectiObjective To observe the effect on the immune response to HBV surface proteinvaccine using DNA prime and HBV protein boost strategy in Balb/c mice.Methods pSW3891(shorten for vector) and pSW3891/MHBs/adr(shorten for adr)encoding the HBV surface middle protein, were transfected into 293T cell withTransfection TM Liposome. Expression of adr and vector in vitro were tested byWestern blot analysis. 18 Balb/c mice were divided into 3 groups :Ⅰ:vector+vector ;Ⅱ:adr+ HBV protein vaccine ;Ⅲ:HBV protein vaccine＋HBV protein vaccine .The mice were seperately vaccined vector , adr or protein at week 0, and vector ,protein or protein at week 4 by intramuscular injection. Titres of anti-HBs in the seraof mice were tested by ELISA. The HBsAg peptide specific IFN-γsecreation murinespleen cells were tested by ELISPOT.Results Expression of adr in vitro was confirmed by Western blot. The anti-HBs canbe tested in both of groupⅡand groupⅢat the second week after firstimmunization, and reached a peak at the sixth week. The ending-point titre of anti-HBs in the pooled sera of groupⅢis up to 1:72900 by ELISA and higher than groupⅡ(1:24300). ELISPOT assay was applied to test the specific cells of INF-γsecretionin spleen cells. 713.94±8.029/105 and 379.22±43.06/105 (X±SD) cells of the HBsAgpeptide specific IFN-γsecreation murine spleen cells were detected by Elispot ingroupⅡand groupⅢseparately. The difference between groupⅡand groupⅢissignificant by statistics.Conclusion HBsAg DNA prime and protein boost strategy could significantlyimprove the cell mediated immune response to HBV surface middle protein in Balb/cmice.