Figure 4. A Type-I IFN signal is essential for the induction of FasL expression on several cells in the lungs of mice lethally infected with the PR/8 virus.
B6 or B6-IFNR-KO mice were infected with 105 pfu/head of the PR/8 virus and sacrificed at 3DPI. The cells in the lungs isolated from the mice were stained with anti-FasL, anti-Fas, or an isotype matched control antibody (Ab) and the Abs for the indicated specific cell type marker proteins. Fluorescent activities of these samples were assessed by flowcytometry. Red or Blue color histogram shows fluorescent signal of isotype matched control Ab of the indicated cell populations in non or lethal infected condition, respectively. Orange or dark green color histogram shows that of the indicated Ab obtained from B6 or B6-IFNR-KO mice in non infected condition, and light green or black color histogram shows the signal of the indicated Ab from B6 or B6-IFNR-KO mice lethally infected, respectively. Upper panel shows results by the assay using anti-FasL specific Ab and lower shows that by the assay using anti-Fas specific Ab.