Korean J Vet Res.  2011 Sep;51(3):193-201.

Development of an attenuated vaccine strain from a korean respiratory type infectious bronchitis virus

• Choi KS
• Jeon WJ
• Lee EK
• Kye SJ
• Park MJ
• Kwon JH

Abstract

An attenuated vaccine strain AVR1/08 of Korean respiratory type of infectious bronchitis virus (IBV) was developed by 89th passages of IBV D85/06 strain in chicken eggs. The AVR1/08 strain had higher virus titer at least 20 times (10(1.3)) than the parent virus D85/06 by egg inoculation method. The AVR1/08 strain had a single point mutation (S to Y) at position 56 of spike protein of IBV compared to parent virus IBV D85/06 strain. The mutation was observed consistently at viruses after 47th passage in chicken eggs. The AVR1/08 strain showed no virulence even after 6 passages in chickens and all chickens inoculated induced anti-IBV antibody 14 days after vaccination. The AVR1/08 strain had broad protective efficacy against QX type Korean nephropathogenic virus (Q43/06 strain), KM91 type Korean nephropathogenic virus (KM91 strain) and Korean respiratory virus (D85/06 strain). In contrast, Massachusetts (Mass) type attenuated vaccine strain H120 showed protection of 37.5 to 50% against these three viruses. Our results indicate that the AVR1/08 strain has potential as an attenuated vaccine effective in controlling IBVs circulating in Korea.

Keyword

attenuation; infectious bronchitis; live vaccine; protection

MeSH Terms

Chickens
Eggs
Humans
Infectious bronchitis virus
Korea
Massachusetts
Ovum
Parents
Point Mutation
Sprains and Strains
Vaccination
Viral Load
Viruses