[Construction of eukaryotic expression plasmids inserting HBsAg gene and DNA immunization responses to HBsAg in mice].
OBJECTIVE
To study the HBsAg transient expression in HepG2 or COS-7 cells with eukaryotic expression plasmids inserting HBsAg gene (pCI-S and pcDNA3.1-S) and the efficacy of naked DNA immunization in mice.


METHODS
Firstly, the recombinant plasmids of pCI-S and pcDNA3.1-S were constructed by the cloning technique and the accuracy of these constructs was confirmed by restriction enzyme digestion and DNA sequencing. Secondly, plasmids of pCI-S and pcDNA3.1-S were transferred into HepG2 and COS-7 cells, respectively by means of cationic liposome. HBsAg transient expression was assayed by ELISA in cell culture supernatants and cell lysates. Thirdly, plasmids were injected into quadriceps muscles of BALB/C mice and serum samples were obtained from individual immunized or control mice 4 weeks after injection and boost injection, respectively. Anti-HBs were assayed in mice sera by ELISA. HBsAg-specific CTL responses of spleen cells from immunized mice were tested by the LDH method.


RESULTS
Plasmids of pCI-S and pcDNA3.1-S allowed HBsAg transient expression in cell culture supernatants and cell lysates of HepG2 or COS-7 cells. Intramuscular immunization of BALB/C mice with plasmids of pCI-S or pcDNA3.1-S elicited the antibody and cytotoxic T lymphocyte responses to HBsAg.


CONCLUSIONS
The vectors used in this study are effective to induce prime antibody and HBsAg-specific-cytotoxic T lymphocyte responses to HBsAg in mice after intramuscular immunization.
Liang
Zengwei
Z
Institute for Viral Hepatitis, Chongqing Medical University, Chongqing 400010, China.
Lan
Yinghua
Y
Li
Yongguo
Y
Cai
Dachuan
D
Ren
Hong
H
D000818:Animals; D019556:COS Cells; D003001:Cloning, Molecular; D004279:DNA, Viral / Q000235:genetics; D005057:Eukaryotic Cells / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D006509:Hepatitis B / Q000276:immunology / Q000517:prevention & control; D006514:Hepatitis B Surface Antigens / Q000235:genetics* / Q000276:immunology; D006524:Hepatitis, Viral, Animal / Q000276:immunology / Q000517:prevention & control; D006801:Humans; D007114:Immunization; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids / Q000235:genetics; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014162:Transfection; D014407:Tumor Cells, Cultured; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology*; D014765:Viral Vaccines / Q000235:genetics / Q000276:immunology
D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D019444:Vaccines, DNA; D014765:Viral Vaccines