Abstract
Avian infectious bronchitis virus (IBV), a coronavirus, requires initial isolation in, and adaptation to, chicken embryos (CE) before transfer to primary avian cell and chicken tracheal organ cultures. These are the only presently known cell cultures in which IBV replicates and produces cytopathic effects (c.p.e.) in serial passage (Estola, 1966; Cunningham, 1970). Monkey kidney cells have been reported (Fahey & Crawley, 1956; Steele & Luginbuhl, 1964) to support relication of IBV without c.p.e. when first inoculated with virus propagated in CE. Attempts apparently were not made to passage the virus in these cells.