Figure 1. Influenza HA targeting mAb FY1 decreases acute lung injury and protects against influenza-associated bacterial pneumonia.

(A) Study design with groups of C57BL/6 mice infected with 100 PFUs of influenza A PR/8/34 and receiving a single dose of FY1 or IgG control on days 1 to 5 after influenza infection. Mice received secondary infection with 5 × 10⁷ CFUs of MRSA on day 6 after influenza, and samples were harvested 24 hours following bacterial infection (n = 8). (B) Bacterial colony counts in the lung. (C and D) Weight loss on days 6 and 7 after influenza infection. (E) Survival curves of mice that received FY1 or IgG control on days 1, 3, or 5 after influenza infection. Mice received secondary infection with 5 × 10⁸ CFUs of MRSA on day 6 after influenza (n = 12). (F and G) Total protein and IgM concentrations in the BALF. *P < 0.05. Significance was tested by 1-way ANOVA using Dunnett’s multiple comparison test except for E where a log-rank Mantel-Cox test was performed. Each experiment was independently performed twice, and data are shown from combined experiments. Data represent mean ± SEM.