title: Effect of serial embryo passage of an Arkansas-type avian infectious bronchitis virus isolate on clinical response, virus recovery, and immunity.
abstract: Infectious bronchitis virus (IBV) Arkansas-type DPI strain (Ark DPI) was attenuated by serial passage in chicken embryos. Virus of passage 50 was less pathogenic for day-old maternally immune broiler-type chickens than virus of passage 10 or 25 as determined by clinical response to vaccination, virus isolation in respiratory (trachea) and nonrespiratory (kidney and cloaca) tissues, and weight-gain studies. Chickens vaccinated with virus of passage 10, 25, or 50 were at least 80% resistant to homologous virus challenge of the upper respiratory tract 4 and 6 weeks postvaccination. Serum antibody production by passage-50-vaccinated chickens was comparatively low at 4 weeks but at 6 weeks was similar to that in chickens vaccinated with virus of passage 10 or 25.
mesh_terms: D000818:Animals; D002642:Chick Embryo; D002645:Chickens; D002988:Cloaca / Q000382:microbiology; D003332:Coronaviridae / Q000472:pathogenicity*; D003333:Coronaviridae Infections / Q000517:prevention & control / Q000662:veterinary*; D001351:Infectious bronchitis virus / Q000276:immunology / Q000302:isolation & purification / Q000472:pathogenicity*; D011201:Poultry Diseases / Q000517:prevention & control*; D014132:Trachea / Q000382:microbiology; D014611:Vaccination / Q000662:veterinary*; D014765:Viral Vaccines / Q000276:immunology; D014774:Virulence; D014776:Virus Cultivation / Q000379:methods
chemical_list: D014765:Viral Vaccines