Post-exposure protection of animals after intranasal infection with a lethal dose of wt VACV and subsequent treatment with different VACV mutants.

<p>(A) Weight loss. Groups of 5 to 10 four-week-old C57BL/6 mice were infected intranasally with 10⁶ pfu (~100 LD_50s) of wt VACV and treated 1 dpi with 10⁷ pfu of VACVE3LΔ7C (○), VACVE3LΔ26C (●), VACVΔE3L (♦), VACVΔE3L::ATVeIF2α (□), v50ΔB13RMγ (▲) and v50ΔB13RMIL-18 (∆). There were two groups of control animals, one group was infected with wt VACV alone and was mock-treated (■), the second group of animals was mock-infected and mock-treated (◊). Each mouse was weighed at the indicated times. Average percentage of initial weight of the animals infected with each virus is plotted versus time (days post-infection). Lines end at the death of one animal. Error bars indicate the standard error of the mean. (B) Survival curve. The data represent a pool of two independent experiments using group sizes of 5 mice. (C) v50ΔB13RMγ dose response. Groups of 10 four-week-old C57BL/6 mice were infected intranasally with 10⁶ pfu of wt VACV (~100 LD_50s) and treated one day post-infection with doses of 10², 10³, 10⁴, 10⁵, 10⁶, 10⁷ and 5 x 10⁸ pfu of v50ΔB13RMγ (▲).