Isolation and assay of rabies serogroup viruses in CER cells

Infection of CER cell cultures with field strains of rabies virus, ranging from 0 to 5 mouse brain passages, was detected by immunoflurescence within 2-4 days after infection. A fluorescent focus assay for measuring infectivity of seven rabies serogroup viruses was rapid and reproducible. Rabies field strians and other rabies serogroup viruses also induced cytopathic effect, usually on initial passage. The hemadsorption-negative (HAD-) plaque test in BSC-1 cells was successfully applied to laboratory-adapted rabies strains. HAD- test attempts were unsuccessful with CER cells and with field isolates of rabies virus in both cell lines. CER cells are heteroploid and are antigenically related to BHK-21 cells by fluorsecent antibody tests.