Infection of NF-kB luciferase transgenic mice.

(A) Groups of 3 immunocompetent mice were infected with 1x10⁵ PFU of the wt or the ΔF2 IAV. Four days pi, mice were anesthetized and luciferine was intra-nasally instilled (0.75 mg.kg^-1). Bioluminescence was then measured using the IVIS system. (B) Bioluminescence analysis of neutropenic mice infected with 1x10⁵ PFU of the wt or the ΔF2 IAV at day 4 pi. The scale on the right indicates the average radiance: the sum of the photons per second from each pixel inside the ROI/number of pixels (photons/sec/cm2/sr). (C) Bioluminescence activities of the 4 groups of mice were quantified using ‘Living Image’ software and represented as a diagram (***: p-value<0.001; ns: non-significant). (D) Body temperature measurement of immunocompetent mice and neutropenic mice challenged by wt or ΔF2 IAV at day 4 pi (**: p-value<0.01; ns: non-significant).