Immunologic analysis induced by DNA vaccine encoding E protein of Beijing-1 strain derived from Japanese encephalitis virus.
OBJECTIVE
We have compared the gene expression and DNA immunization efficacy encoding prME and E proteins of a different strain (JaGAr-01) derived from Japanese encephalitis virus. This study aimed to construct a recombinant encoding E protein of the Beijing-1 strain derived from Japanese encephalitis virus and analyze the humoral, cellular and protective immunity induced by the above recombinant.


METHODS
The recombinant pJBE containing E (1,500 bps) gene from the Beijing-1 strain of Japanese encephalitis virus was constructed and then transfected into the HepG2 cell line by liposome fusion. The expression of E (about 53 kD) protein in transfected cells was analyzed by Western blot using a specific anti-JEV-E antibody. BALB/c mice were vaccinated with 3 microg of pJBE by the gene-gun technique. JaGAr-01 and Beijing-1 strains (10(5) PFU/100 microl) of Japanese encephalitis virus were given to BALB/c mice by intraperitoneal injection 3 weeks after double DNA immunization with a lethal virus challenge. BALB/c mice were observed for 21 days after challenge. An 80% plaque reduction neutralization test was performed to titrate the neutralization antibody before and after viral challenge. A lactate dehydrogenase activity release test was used to examine cytotoxic T lymphocyte activity after double DNA immunization.


RESULTS
The expression of about 53 kD protein associated with pJBE was determined in transfected HepG2 cells with specific anti-JEV-E antibody. A higher level of neutralization antibodies and the cytotoxicity effect were induced with pJBE immunization using the gene-gun technique, and were similar to those induced with inactivated vaccine derive from the Beijing-1 strain of Japanese encephalitis virus. Balb/c mice immunized with pJBE survived the challenge with the different strains of Japanese encephalitis virus; however, Balb/c mice immunized with inactivated vaccine did not survive the challenge with the JaGAr-01 strain of Japanese encephalitis virus at all.


CONCLUSIONS
DNA vaccine containing the E protein gene derived from Japanese encephalitis virus can provide not only better efficacy including humoral and cellular immunity, but also cross-protection against infection with homologous and heterologous Japanese encephalitis virus.
Feng
Guo-he
GH
Department of Infectious Diseases, Second Affiliated Hospital of China Medical University, Shenyang, China. fenggh@cmu2h.com
Liu
Ning
N
Zhou
Yan
Y
Zhai
Yong-zhen
YZ
Li
Xi-mei
XM
Dou
Xiao-guang
XG
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D019470:Biolistics; D015153:Blotting, Western; D002460:Cell Line; D004195:Disease Models, Animal; D004664:Encephalitis Virus, Japanese / Q000276:immunology*; D005260:Female; D022781:Hepatocytes / Q000737:chemistry / Q000821:virology; D006801:Humans; D007274:Injections, Intraperitoneal; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D009500:Neutralization Tests; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D016019:Survival Analysis; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D019444:Vaccines, DNA / Q000276:immunology*; D014759:Viral Envelope Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D010948:Viral Plaque Assay; D014765:Viral Vaccines / Q000276:immunology*
D000914:Antibodies, Viral; D008562:Membrane Glycoproteins; D011994:Recombinant Proteins; D019444:Vaccines, DNA; D014759:Viral Envelope Proteins; D014765:Viral Vaccines; C080628:glycoprotein E, Japanese encephalitis virus; D007770:L-Lactate Dehydrogenase