An in vitro assay for quantifying the virus of avian encephalomyelitis.

Chicken embryo brain (CEB) cell cultures support the replication of embryo-adapted strains, vaccine strains, and field isolates of avian encephalomyelitis virus. A centrifugal force of 1,500 X g was applied during virus adsorption. Viral antigen was detected in the infected cells by using the indirect fluorescent-antibody technique (IFAT). Combining the infectivity of the virus in CEB cell culture with the ability to detect viral antigen by the IFAT resulted in the development of a virus-titration method. This in vitro assay proved to be more sensitive than the standard embryo-inoculation assay. It was concluded that the in vitro assay provides a satisfactory alternative to the embryo-inoculation assay.