IFNG and influenza: The influenza-specific IFN-γ production profile following the first challenge (up to day 26), measured by area under the curve for each ferret, was not significantly different between groups H1/H3, H1/H1 and H1/cull, but each produced significantly more influenza-specific IFN-γ than mock-infected group PBS/H3 (Supplementary Fig. 3; Mann-Whitney test, p < 0.04).