Assay of bovine interferons in cultures of the porcine cell line IB-RS-2.

An assay for bovine interferons has been developed using the porcine cell line IB-RS-2 and a bovine enterovirus, CBV-D, as challenge virus. The method is based on estimation of cytopathic effect measured by uptake of neutral red. Teh assay is simple, sensitive, and reproducible. A comparative test of different viruses in IB-RS-2 cells and secondary calf kidney cells revealed that the sensitivity of a virus to interferon can vary up to 1,000-fold in the two cell systems. Vesicular stomatitis virus was found to be rather insensitive to interferon in IB-RS-2 cells.