FIG. 4.

Repeated intranasal treatment increases protective effect of ftIFN-α. Groups of six animals were treated with 300 μl of undiluted supernatant of transfected 293T cells containing ftIFN-α or 300 μl of supernatant of mock-transfected 293T cells at 20 and 4 h before infection with 10⁵ TCID₅₀ of H1N1 influenza A virus strain USSR/77. Two more treatments were done at 24 and 48 h postinfection. (A) Viral titers in nasal washes. (Inset) Results of statistical analysis of circled data points. (B) Cell counts in nasal washes (NW). (Inset) Results of statistical analysis of circled data points. Error bars represent the standard deviation. (C) Body temperature as measured by telemetry. Average values of groups of three animals are shown. (D) Respiratory signs. The scoring criteria outlined in the legend to Fig. 2 were used.