Figure 4.

Resistance of FMS₇–IFN-α2 to inactivation in human serum. FMS₇–IFN-α2 and native IFN-α2 were incubated in human serum at 37°C. At the indicated time points, aliquots were tested for antiviral potency to inhibit VSV-induced cytopathic effects in human WISH cells (see Materials and Methods). (A) Antiviral activity of native IFN-α2. (B) Aliquots of FMS₇–IFN-α2 incubated in serum were either introduced directly to WISH cells (dashed columns) or pretreated for 18 h at pH 8.5, 37°C (open columns).