Plaque Assay 5610 5 MDCK [from ATCC] and HBEC-30KT cells [34] were plated in 6 well plates and grown to confluence overnight. Cells were infected with WSN virus at 10 fold dilutions with a starting concentration of 10 8 pfu/ml. Infected cells were allowed to incubate at 37uC with tilting every 10 minutes. After incubation liquid was aspirated and 2 ml of agar solution was added to wells and allowed to solidify for 1 min. Plates were incubated for 48 hrs at 37uC. Following incubation plates were fixed with formaldehyde for 1 hr. Fixative and agar was removed and cells were stained with crystal violet.