Studies on cell cultures as a method used for adaptation of infectious bronchitis virus

ABSTRACT

The infectious bronchitis virus [IBV] was passaged ten successive times in both of chicken embryo fibroblast [CEF] as primary cell culture origenated from a specific host and baby hamester kidney [BHK] and African green monkey kidney [VERO] cell cultures as cell lines origenated from non-specific mammelian hosts aiming to obtain a cell culture-adapte IBV to be used in the different serological experiments instead of embryonated chicken eggs which usually associated with some problems in addition to the long time consumed and the relatively higher economic costs. It was found that the cytopathic effect [CPE] of the virus began to appear on the 7[th], 6[th] and 5[th] day post infection of CEF, BHK and VERO cells respectively while the harvestation time was on the 10[th] day post infection in the 3 cell cultures. The periods on which the CPE and harvestatin were detected, began to decrease by the successive virus passages to become fixed 2 and 3 days post cell infection respectively after the 8[th]. passage in CEF, 16[th]. passage in BHK and 5[th] passage in VERO. The obtained virus titre, after 10 passages, was 10[6], 10[7] and 10[8] TCID[50] /0.1 ml in CEF, BHK and VERO cells respectively. The growth curve of IBV in the used cell cultures, revealed that the optimum time for virus harvestation is 72 hours post cell infection. It was concluded that the IBV could be successfully adapted to cell culture to be used in different serological tests to avoid the use of embryonated chicken eggs