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Figure 1 | Virology Journal

Figure 1

From: Defective interfering virus protects elderly mice from influenza

Figure 1

A single dose of influenza A virus 244/PR8 given 1 day before infection protects elderly (18-month-old) mice from influenza, and these mice are then immune to further challenge. Mice were anaesthetized and inoculated intranasally on day -1 with 244/PR8 or inactivated 244/PR8 (solid arrow), and were infected on day 0 (open arrow) with influenza A/WSN (panels a, b). Mice that had survived WSN challenge through treatment with protecting virus in a, b were challenged with a second high dose of WSN 3 weeks after the first infection (panels c, d) to establish their immune status. These mice were inoculated intranasally (open arrow) with a 500-fold higher dose of WSN than used in (a, b). (a, c) mean clinical disease assessment; (b, d) percentage weight change. ■, 12 μg 244/PR8 followed by WSN (n = 5); ▲, 12 μg inactivated 244/PR8 followed by WSN (n = 6); , 12 μg 244/PR8 followed by diluent (n = 2); , naïve 5-week-old mice given only the high dose WSN challenge (n = 5). Mice were assessed clinically and weighed daily. Weights are not presented after 2 or more mice died. The percentage of mice surviving at the end of the study is in parenthesis. Data are representative of two separate experiments.

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