The IFAT is conducted directly after virus isolation in cell culture.
i) Prepare monolayers of cells on cover-slips to reach approximately 80% confluence, which is
usually achieved within 24 hours of incubation at 25°C. The FBS content of cell culture medium
is reduced to 2%.
ii) When the cell monolayers are ready, inoculate the virus suspension to be identified at tenfold
dilution steps by adding directly into the cell culture wells or flasks.
iii) Incubate at 25°C for 24–72 hours.
iv) When CPE appears, remove the cell culture medium, rinse three times with phosphate-buffered
saline (PBS). Air-dry the infected cells and fix with cold acetone (stored at –20°C) for 10 minutes.
v) Allow the cell monolayers to air-dry for at least 30 minutes and process immediately or freeze at –20°C.