Characterisation of immune responses and protective efficacy in mice after immunisation with Rift Valley Fever virus cDNA constructs.
BACKGROUND
Affecting both livestock and humans, Rift Valley Fever is considered as one of the most important viral zoonoses in Africa. However, no licensed vaccines or effective treatments are yet available for human use. Naked DNA vaccines are an interesting approach since the virus is highly infectious and existing attenuated Rift Valley Fever virus vaccine strains display adverse effects in animal trials. In this study, gene-gun immunisations with cDNA encoding structural proteins of the Rift Valley Fever virus were evaluated in mice. The induced immune responses were analysed for the ability to protect mice against virus challenge.


RESULTS
Immunisation with cDNA encoding the nucleocapsid protein induced strong humoral and lymphocyte proliferative immune responses, and virus neutralising antibodies were acquired after vaccination with cDNA encoding the glycoproteins. Even though complete protection was not achieved by genetic immunisation, four out of eight, and five out of eight mice vaccinated with cDNA encoding the nucleocapsid protein or the glycoproteins, respectively, displayed no clinical signs of infection after challenge. In contrast, all fourteen control animals displayed clinical manifestations of Rift Valley Fever after challenge.


CONCLUSIONS
The appearance of Rift Valley Fever associated clinical signs were significantly decreased among the DNA vaccinated mice and further adjustment of this strategy may result in full protection against Rift Valley Fever.
Lagerqvist
Nina
N
Swedish Defence Research Agency, Department of CBRN Defence and Security, Umeå, Sweden. nialat02@student.umu.se
Näslund
Jonas
J
Lundkvist
Ake
A
Bouloy
Michèle
M
Ahlm
Clas
C
Bucht
Göran
G
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D019470:Biolistics; D002460:Cell Line; D018076:DNA, Complementary / Q000235:genetics / Q000276:immunology; D005260:Female; D006023:Glycoproteins / Q000235:genetics / Q000276:immunology; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D019590:Nucleocapsid Proteins / Q000235:genetics / Q000276:immunology; D012295:Rift Valley Fever / Q000276:immunology* / Q000517:prevention & control* / Q000821:virology; D012296:Rift Valley fever virus / Q000235:genetics / Q000276:immunology*; D014611:Vaccination; D019444:Vaccines, DNA / Q000008:administration & dosage* / Q000276:immunology; D014765:Viral Vaccines / Q000008:administration & dosage* / Q000276:immunology
D000914:Antibodies, Viral; D018076:DNA, Complementary; D006023:Glycoproteins; D019590:Nucleocapsid Proteins; D019444:Vaccines, DNA; D014765:Viral Vaccines