Interferon Binding: The First Step in Establishment of Antiviral Activity

Chick cells incubated at 1°C with interferon fail to develop antiviral activity, but this activity appears subsequent to a 7-hour incubation at 37°C after removal of interferon by repeated washings. Treatment with actinomycin D blocks the development of the latter activity. Cells incubated with interferon at 1°C for up to 1 hour and then washed and incubated for 2 hours at 37°C develop a degree of antiviral activity proportional to the concentration of interferon at initial incubation; at any concentration, the antiviral activity increased with the duration of initial incubation at 1°C, but a maximal response was reached at 10 or 20 minutes. Treatment with trypsin after incubation with interferon at 1°C inhibited development of antiviral activity. Interferon is rapidly bound to a superficial cell site, and this binding is necessary for development of antiviral activity in chick cells.