Construction and immunogenicity of a recombinant fowlpox vaccine coexpressing S1 glycoprotein of infectious bronchitis virus and chicken IL-18.
Infectious bronchitis virus (IBV) poses a major threat to the chicken industry worldwide. In this study, we developed a recombinant fowlpox virus (rFPV) vaccine expressing the IBV S1 gene and chicken interleukin-18 gene (IL-18), rFPV-S1/IL18. Recombinant plasmid pSY-S1/IL18 was constructed by cloning chicken IL-18 into fowlpox virus transfer plasmid containing S1 gene and transfected into the chicken embryo fibroblasts cell pre-infected with S-FPV-017 to generate rFPV-S1/IL18. Expression of the recombinant proteins was confirmed by RT-PCR and IFA. We also constructed the recombinant fowlpox virus rFPV-S1 without IL-18. One-day-old chickens were vaccinated by wing-web puncture with the two rFPVs, and the induced humoral and cellular responses were evaluated. There was a significant difference in ELISA antibody levels (P<0.05) elicited by either rFPV-S1 or rFPV-S1/IL18. The ratios of CD4(+) to CD8(+) in chickens immunized with rFPV-S1/IL18 were significantly higher (P<0.05) than in those immunized with rFPV-S1. All chickens immunized with rFPV-S1/IL18 were completely protected (20/20) after challenge with the virulent IBV HN99 strain 43 days after immunization, while only 15 out of 20 of the chickens immunized with the rFPV-S1 were protected. Our results show that the protective efficacy of the rFPV-S1 vaccine could be enhanced significantly by simultaneous expression of IL-18.
Chen
Hong-Ying
HY
College of Animal Science and Veterinary Medicine, Henan Agricultural University, Wenhua Road 95#, 450002 Zhengzhou, Henan Province, People's Republic of China.
Yang
Ming-Fan
MF
Cui
Bao-An
BA
Cui
Pei
P
Sheng
Min
M
Chen
Guo
G
Wang
Shu-Juan
SJ
Geng
Jing-Wei
JW
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002645:Chickens; D018352:Coronavirus Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D004797:Enzyme-Linked Immunosorbent Assay; D005587:Fowlpox virus / Q000235:genetics*; D005822:Genetic Vectors; D020382:Interleukin-18 / Q000235:genetics / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology*; D011201:Poultry Diseases / Q000276:immunology / Q000517:prevention & control*; D064370:Spike Glycoprotein, Coronavirus; D016019:Survival Analysis; D014611:Vaccination / Q000379:methods; D014614:Vaccines, Synthetic / Q000235:genetics / Q000276:immunology; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology*; D014765:Viral Vaccines / Q000235:genetics / Q000276:immunology*
D000914:Antibodies, Viral; D020382:Interleukin-18; D008562:Membrane Glycoproteins; D064370:Spike Glycoprotein, Coronavirus; D014614:Vaccines, Synthetic; D014759:Viral Envelope Proteins; D014765:Viral Vaccines