Figure 5. Spred-2 in nonimmune cells plays critical role against influenza virus infection.

The following bone marrow chimeras were created (donor → host): WT → WT, Spred-2 KO → WT, Spred-2 KO → Spred-2 KO, and WT → Spred-2 KO. 8 weeks after reconstitution, bone marrow chimeras were intranasally infected with influenza virus (1 × 10² pfu), and then sacrificed at 5 days post-infection. (A) Representative photomicrographs of hematoxylin-stained lung sections of WT → WT, KO → WT, KO → KO, and WT → KO chimeras at day 5 post-H1N1 infection. Original magnification, ×40; ×200. (B) Quantitative analysis of histopathologic changes using a scoring system detailed in the methods. (C) Viral load in BM-chimera mice measured by TCID₅₀. (D) Absolute numbers of inflammatory leukocytes in the BAL fluid of BM-chimera mice. SP2KO = Spred-2 KO. *p < 0.05, **p < 0.01 compared with when both donors and recipients were from WT mice. Data shown indicate mean ± SEM and are from a representative experiment of 2 independent experiments. Each group had 4–6 mice per group.