Measurement of Antigenic and Pathogenic Variability of Infectious Bronchitis Virus Strains by Trachea Culture

Factors influencing the outcome of infectious bronchitis vaccination and challenge experiments

“…For very many years, assays were performed by titration in embryonated eggs, expressing the results in terms of EID 50 . However, subsequently, tracheal organ cultures (TOCs) have been used (Cook et al, 1976;Andrade et al, 1982) and shown to be at least as sensitive as embryonated eggs for isolating or assaying IBV (Cook et al, 1976) and to give more reproducible results (Johnson & Newman, 1971). However, titres can differ significantly depending whether they are expressed in EID 50 or median ciliostatic doses.…”

The use of chicken tracheal organ cultures for the isolation and assay of avian infectious bronchitis virus

“…Chicken tracheal organ cultures have been shown to be susceptible to infection with AIB virus and may be employed as an accurate assay system if eiliostasis is used as the criterion of infection (12,4,13,2,7). Furthermore, JOHNSO~ ~ and N~wMA~ (13) found that tracheal explants provided a better assay system than embryonated chicken eggs because the results were more reproducible.…”

“…Furthermore, JOHNSO~ ~ and N~wMA~ (13) found that tracheal explants provided a better assay system than embryonated chicken eggs because the results were more reproducible.…”

Organ culture in avian virology: A review

“…This property of ciliostasis was used in neutralisation tests with an IBV-immune mouse ascitic fluid. Johnson and Newman (1971) pursued their original investigations (Johnson et al, 1969) and compared the titres of IBV assayed in embryonated eggs and chicken tracheal explants. Five IBV serotypes were cultivated for ten serial passages in both eggs and tracheal cultures, and their titres assayed in both systems.…”

“…Titres of tracheal culture assays were superior to those of eggs, and no significant antigenic changes attributable to serial passage were observed. Whereas Cherry and Taylor-Robinson (1970) had demonstrated the feasibility of neutralisation tests in organ culture using a constant virus dose against dilutions of mouse immune ascitic fluid, Johnson and Newman (1971) used a constant scrum-varying virus technique to show that IBV strains maintained the same antigenic behaviour under all passage conditions examined.…”