title: HBV DNA vaccine with adjuvant cytokines induced specific immune responses against HBV infection.
abstract: OBJECTIVE
  To seek for an effective method to improve the immune responses induced by DNA vaccine expressing HBV surface antigen (pCR3.1-S) in Balb/c mice (H-2(d)).
  
  
  METHODS
  The pCR3.1-S plasmid and the eukaryotic expression vectors expressing murine IL-2 (pDOR-IL-2) or IL-12 (pWRG3169) were injected into mice subcutaneously. The immune responses to pCR3.1-S and the adjuvant effect of the cytokines plasmid were studied. Meanwhile the effect of pCR3.1-S on anti-translated subcutaneous tumor of P815 mastocytoma cells stably expressing HBsAg (P815-HBV-S) was also studied. Anti-HBs in serum was detected by enzyme-linked immunoadsorbent assay (ELISA) and HBsAg specific cytotoxic T lymphocytes (CTLs) activity was measured by (51)Cr release assay. After three weeks of DNA immunization, the cells of P815-HBV-S were inoculated into mice subcutaneously and the tumor growth was measured every five days. The survival rate and living periods of mice were also calculated.
  
  
  RESULTS
  After 8 wk DNA immunization, the A 450 nm values of sera in mice immunized with pCR3.1, pCR3.1-S and pCR3.1-S codeliveried with IL-2 or IL-12 plasmids were 0.03+/-0.01, 1.24+/-0.10, 1.98+/-0.17 and 1.67+/-0.12 respectively. Data in mice codeliveried pCR3.1-S with IL-2 or IL-12 plasmids were significantly higher than that of mice injected pCR3.1 or pCR3.1-S only. The HBsAg specific CTL activities in mice coinjected with pCR3.1-S and IL-2 or IL-12 eukaryotic expression vectors were (61.9+/-7.1) % and (73.3+/-8.8) %, which were significantly higher than that of mice injected with pCR3.1 (10.1+/-2.1) % or pCR3.1-S (50.5 +/-6.4) %. The HBsAg specific CTL activities in mice injected with pCR3.1, pCR3.1-S, pCR3.1-S combined with IL-2 or IL-12 eukaryotic expression vectors decreased significantly to (3.2+/-0.8) %, (10.6+/-1.4) %, (13.6+/-1.3) % and (16.9+/-2.3) % respectively after the spleen cells were treated by anti-CD8(+) monoclonal antibody, but presented no significant change to anti-CD4(+) monoclonal antibody or unrelated to monoclonal antibody. The HBV-S DNA vaccine (pCR3.1-S) could evidently inhibit the tumor growth, prolong the survival period of mice and improve the survival rate of mice and these effects could be improved by IL-12 gene codeliveried.
  
  
  CONCLUSIONS
  HBV DNA vaccine has a strong antigenicity in humoral and cellular immunities, which can be promoted by plasmid expressing IL-2 or IL-12. CD8+ cells executed the CTL activities. DNA vaccine may be useful for both prophylaxis and treatment of HBV infection.
authors.affiliation: Department of Infectious Diseases, Tangdu Hospital, the Fourth Military Medical University, Xi'an 710038, Shaanxi Province, China. ddw0715@yahoo.com.cn
authors.forename: De-Wei
authors.initials: DW
authors.lastname: Du
authors.forename: Zhan-Sheng
authors.initials: ZS
authors.lastname: Jia
authors.forename: Guang-Yu
authors.initials: GY
authors.lastname: Li
authors.forename: Yong-Ying
authors.initials: YY
authors.lastname: Zhou
mesh_terms: D000276:Adjuvants, Immunologic; D000818:Animals; D003602:Cytotoxicity, Immunologic; D005822:Genetic Vectors; D006509:Hepatitis B / Q000276:immunology / Q000517:prevention & control / Q000628:therapy; D006510:Hepatitis B Antibodies / Q000097:blood*; D006514:Hepatitis B Surface Antigens / Q000276:immunology*; D017325:Hepatitis B Vaccines / Q000276:immunology*; D006515:Hepatitis B virus / Q000235:genetics* / Q000276:immunology; D006801:Humans; D018664:Interleukin-12 / Q000235:genetics / Q000276:immunology; D007376:Interleukin-2 / Q000235:genetics / Q000276:immunology; D007378:Interleukins / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009368:Neoplasm Transplantation; D010957:Plasmids; D014407:Tumor Cells, Cultured; D019444:Vaccines, DNA / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines; D007376:Interleukin-2; D007378:Interleukins; D019444:Vaccines, DNA; D018664:Interleukin-12