Protection of chickens against infectious bronchitis by a recombinant fowlpox virus co-expressing IBV-S1 and chicken IFNgamma.
A fowlpox virus expressing the chicken infectious bronchitis virus (IBV) S1 gene of the LX4 strain (rFPV-IBVS1) and a fowlpox virus co-expressing the S1 gene and the chicken type II interferon gene (rFPV-IBVS1-ChIFNgamma) were constructed. These viruses were assessed for their immunological efficacy on specific-pathogen-free (SPF) chickens challenged with a virulent IBV. Although the antibody levels in the rFPV-IBVS1-ChIFNgamma-vaccinated group were lower than those in the attenuated live IB vaccine H120 group and the rFPV-IBVS1 group, the rFPV-IBVS1-ChIFNgamma provided the strongest protection against an IBV LX4 virus challenge (15 out of 16 chickens immunized with rFPV-IBVS1-ChIFNgamma were protected), followed by the attenuated live IB vaccine (13/16 protected) and the rFPV-IBVS1 (12/16 protected). Compared to those of the rFPV-IBVS1 and the attenuated live IB vaccine groups, chickens in the rFPV-IBVS1-ChIFNgamma group eliminated virus more quickly and decreased the presence of viral antigen more significantly in renal tissue. Examination of affected tissues revealed abnormalities in the liver, spleen, kidney, lung and trachea of chickens vaccinated with the attenuated live IB vaccine and the rFPV-IBVS1 vaccine. In rFPV-IBVS1-ChIFNgamma-vaccinated chickens, pathological changes were also observed in those organs, but were milder and lasted shorter. The lesions in the mock control group were the most severe and lasted for at least 20 days. This study demonstrated that chicken type II interferon increased the immunoprotective efficacy of rFPV-IBVS1-ChIFNgamma and normal weight gain in vaccinated chickens although it inhibited serum antibody production.
Division of Avian Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150001, PR China.
Yun-Feng
YF
Wang
Yong-Ke
YK
Sun
Zhan-Cheng
ZC
Tian
Xing-Ming
XM
Shi
Guang-Zhi
GZ
Tong
Sheng-Wang
SW
Liu
Hai-Dong
HD
Zhi
Xian-Gang
XG
Kong
Mei
M
Wang
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology; D002642:Chick Embryo; D002645:Chickens / Q000276:immunology; D018352:Coronavirus Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D005587:Fowlpox virus / Q000276:immunology*; D056724:Immunity, Humoral; D001351:Infectious bronchitis virus / Q000276:immunology; D007371:Interferon-gamma / Q000276:immunology; D008562:Membrane Glycoproteins / Q000276:immunology*; D011201:Poultry Diseases / Q000276:immunology / Q000517:prevention & control*; D064370:Spike Glycoprotein, Coronavirus; D014613:Vaccines, Attenuated / Q000276:immunology; D014614:Vaccines, Synthetic / Q000276:immunology; D014759:Viral Envelope Proteins / Q000276:immunology*; D014765:Viral Vaccines / Q000276:immunology*
D000914:Antibodies, Viral; D008562:Membrane Glycoproteins; D064370:Spike Glycoprotein, Coronavirus; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic; D014759:Viral Envelope Proteins; D014765:Viral Vaccines; D007371:Interferon-gamma