J Vet Sci.  2005 Jun;6(2):125-133.

Immunogenicity of baculovirus expressed recombinant proteins of Japanese encephalitis virus in mice

• Yang DK
• Kweon CH
• Kim BH
• Lim SI
• Kwon JH
• Kim SH
• Song JY
• Han HR

Abstract

Genes encoding for the premembrane and envelope (prME), envelope (E) and nonstructural protein (NS1) of Japanese encephalitis virus (JEV) were cloned. Each protein was expressed in baculovirus expression system. Of the three proteins expressed in baculovirus system, only prME had hemagglutination activity. The prME (72 and 54 kDa), E (54 kDa) and NS1 (46 kDa) proteins could be detected by Western blotting in the recombinant virus infected cells. Immunogenicity of the recombinant proteins obtained from infected Spodoptera frugiperda (Sf-9) cells was examined in mice. The 3 week-old ICR mice immunized intraperitoneally with three recombinant proteins three times were challenged with a lethal JEV. A survival rate was increased from about 7.7% in unimmunized mice to 92.3% in E + prME and only E groups. The complete protection was shown in prME and live vaccine inoculated groups, respectively. We also measured neutralizing antibody and three immunoglobulin subtypes of IgG1, IgG2a and IgG2b in the sera of mice before and after challenge. Titers of IgG1 antibodies were approximately two to three times higher than that of IgG2b antibodies in all the immunized groups as compared to the control group. However, IgG2a antibody level somewhat increased after challenge, indicating T-helper type 1 (Th1) cell response. The results of this study can provide useful information for developing efficacious subunit vaccine against JEV.

Keyword

baculovirus; Japanese encephalitis virus; JEV; protective immunity

MeSH Terms

Animals
Antibodies, Viral/blood
Baculoviridae/genetics
Blotting, Western
Cloning, Molecular
Encephalitis Virus, Japanese/genetics/*immunology
Encephalitis, Japanese/*immunology/prevention&control
Female
Immunization
Immunoglobulin Isotypes/blood
Japanese Encephalitis Vaccines/*immunology/standards
Mice
Mice, Inbred ICR
Microscopy, Fluorescence
Plasmids
Recombinant Proteins/genetics/immunology
Viral Envelope Proteins/genetics/*immunology
Viral Matrix Proteins/genetics/*immunology
Viral Nonstructural Proteins/genetics/*immunology