Cloning, protein expression and immunogenicity of HBs-murine IL-18 fusion DNA vaccine.
Hepatitis B is a global serious disease caused by hepatitis B virus (HBV). There is no known cure for hepatitis B. The best way to deal with the disease is by preventing with hepatitis B vaccine. However, the current protein-based vaccines made up of recombinant hepatitis B surface antigen (HBsAg) are ineffective in chronic HBV carriers and a significant number of the vaccinees do not mount the protective immune response. Novel DNA-based immunization may overcome the deficits of the protein-based immunization and may provide more effective prophylactic and therapeutic outcomes. In this study, we constructed a recombinant plasmid carrying gene encoding the HBV surface antigen (HBs) linked to DNA segment encoding full-length murine interleukin-18, i.e. pcDNA-HBs-IL-18. Immunogenicity of the DNA construct was carried out in BALB/c mice in comparison with mock, i.e. pcDNA3.1+ and vaccines comprised of pRc/CMV-HBs and pRc/CMV-HBs plus pcDNA-IL-18. All vaccinated mice revealed significant serum anti-HBs IgG response after two intramuscular injections of the vaccines at 28 day interval as compared to the level of mock. Co-administration of pRc/CMV-HBs and pcDNA-IL-18 elicited arbitrarily higher levels of anti-HBs IgG than the levels in mice immunized with pRc/CMV-HBs alone and mice that received pcDNA-HBs-IL-18 although not statistically different. Further experiments are needed to investigate the subisotypes of the IgG antibody, the kinetics of cytokine and the cell-mediated immune response. For this communication, the prototype HBs-IL-18 DNA vaccine was successfully constructed and the gene encoding murine IL-18 was successfully cloned. The latter can be co-injected with the antigen coding DNA or used as a fusion partner to the DNA for priming the immune response. The recombinant HBs and full-length IL-18 proteins have potential for other research purposes. They may be used also as standard proteins in the protein quantification assay.
Channarong
Sunee
S
Faculty of Pharmacy, Mahidol University, Bangkok.
Mitrevej
Ampol
A
Sinchaipanid
Nuttanan
N
Usuwantim
Kanchana
K
Kulkeaw
Kasem
K
Chaicumpa
Wanpen
W
D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology; D006509:Hepatitis B / Q000235:genetics / Q000276:immunology* / Q000517:prevention & control; D006514:Hepatitis B Surface Antigens / Q000235:genetics / Q000276:immunology*; D017325:Hepatitis B Vaccines / Q000235:genetics / Q000276:immunology*; D006515:Hepatitis B virus / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D007074:Immunoglobulin G / Q000276:immunology; D020382:Interleukin-18 / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology*
D000914:Antibodies, Viral; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines; D007074:Immunoglobulin G; D020382:Interleukin-18; D011993:Recombinant Fusion Proteins; D019444:Vaccines, DNA