Safety and efficacy of an attenuated Chinese QX-like infectious bronchitis virus strain as a candidate vaccine.
Infectious bronchitis (IB) is a highly contagious respiratory and urogenital disease of chickens caused by infectious bronchitis virus (IBV). This disease is of considerable economic importance and is primarily controlled through biosecurity and immunization with live attenuated and inactivated IB vaccines of various serotypes. In the present study, we tested the safety and efficacy of an attenuated predominant Chinese QX-like IBV strain. The results revealed that the attenuated strain has a clear decrease in pathogenicity for specific-pathogen-free (SPF) chickens compared with the parent strain. Strain YN-inoculated birds had clinical signs of varying severity with 30% mortality, while the attenuated group appeared healthy, with less tissue damage. The attenuated strain also had relatively low tissue replication rates and higher antibody levels. The superior protective efficacy of the attenuated strain was observed when vaccinated birds were challenged with a homologous or heterologous field IBV strain, indicating the potential of the attenuated YN (aYN) as a vaccine. Producing a vaccine targeting the abundant serotype in China is essential to reducing the economic impact of IB on the poultry industry.
Key Laboratory of Animal Epidemiology and Zoonoses, Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100193, People's Republic of China.
Ye
Y
Zhao
Key Laboratory of Animal Epidemiology and Zoonoses, Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100193, People's Republic of China.
Jin-long
JL
Cheng
Key Laboratory of Animal Epidemiology and Zoonoses, Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100193, People's Republic of China.
Xiao-yu
XY
Liu
Key Laboratory of Animal Epidemiology and Zoonoses, Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100193, People's Republic of China.
Jing
J
Zhao
Key Laboratory of Animal Epidemiology and Zoonoses, Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100193, People's Republic of China.
Yan-xin
YX
Hu
Key Laboratory of Animal Epidemiology and Zoonoses, Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100193, People's Republic of China. Electronic address: zhanggz@cau.edu.cn.
Guo-zhong
GZ
Zhang
D000818:Animals; D002645:Chickens / Q000821:virology*; D002681:China; D018352:Coronavirus Infections / Q000517:prevention & control / Q000662:veterinary* / Q000821:virology; D001351:Infectious bronchitis virus / Q000276:immunology* / Q000472:pathogenicity; D011201:Poultry Diseases / Q000517:prevention & control* / Q000821:virology; D013047:Specific Pathogen-Free Organisms; D014611:Vaccination / Q000662:veterinary; D014613:Vaccines, Attenuated / Q000009:adverse effects / Q000276:immunology / Q000592:standards; D014765:Viral Vaccines / Q000009:adverse effects / Q000276:immunology / Q000592:standards*
D014613:Vaccines, Attenuated; D014765:Viral Vaccines
Attenuated virus; Efficacy; Infectious bronchitis virus; Pathogenicity; Safety