Study on DNA immune of envelope protein gene of Rift Valley Fever Virus

Abstract:

DNA vaccines have successfully induced effective antibody and cellular immune response to many viral pathogens. The antibody response of DNA immunization induction in mouse model with envelope glycoproteins of Rift Valley Fever Virus(RVFV),G(N+C),GN and GC was investigated. For this purpose, three codon G(N+C),GN and GC gene were insert into mammalian expression vector pCAGGS under chicken β-actin promoter to construct pCAGG-RVFV-GN, pCAGG-RVFV-GC and pCAGG-RVFV-G(N+C). The expression of recommbinant GN or / and GC protein in BHK cells transfected with pCAGG-RVFV-GC or pCAGG-RVFV-G(N+C) DNA were confirmed by immunoprecipitation. Six-week-old female BALB/c mice were intramuscularly primed with 100(g pCAGG-RVFV-GN+pCAGG-RVFV-GC+pCAGG-RVFV-G(N+C), and boosted with same dose after 4 weeks. The serums were collected at 3 weeks post final boost. The serum IgG against Rift Valley Fever Virus G(N+C) protein were detect by indirect ELISA using recombinant Baculovirus expressed Rift Valley Fever Virus GN and GC glycoprotein. The mixture of pCAGG-RVFV-GN, pCAGG-RVFV-GCand pCAGG-RVFV-G(N+C) elicited much strong IgG response. For serum neutralization antibody assay, a recombinant Vesicular Stomatitis Virus pseudotype, in which the VSV envelope protein G gene was replaced with the green fluorescent protein gene (VSVΔG*G, Whitt M A) and complemented with Rift Valley Fever Virus G(N+C) glycoprotein expressed in transient (VSVΔG* RVFV-G), was use to replace the authentic Rift Valley Fever Virus. The mixture of pCAGG-RVFV-GN, pCAGG-RVFV-GCand pCAGG-RVFV-G(N+C) also induced high titer of neutralization antibody response. These result indicates that DNA immunization is an efficient vaccine strategy against Rift Valley Fever Virus.