Figure 1. Lingering inflammatory cytokines and lung damage in aged lungs during influenza infection.

Young (2-3 mos.) and aged (19-22 mos.) C57BL/6 mice were infected intranasally with 400 EID₅₀ of PR8 influenza. On 1, 3, 6, 9 and 12 dpi, BAL fluid and cells and lung tissue was harvested; mRNA was isolated from lung tissue. A. The total number of copies of influenza PA was determined by real-time PCR of mRNA from lung tissue. B. Albumin in the BAL was determined by ELISA and C. Cytokines in the BAL were determined by multiplex analysis. The percentage D. and number E. of macrophages, neutrophils and lymphocytes in the BAL was determined by differential staining. For all experiments, data shown is combined from 2 independent experiments and each symbol represents a single animal; line shows the mean. *p < 0.05 by 2 way ANOVA with Bonferroni posthoc correction.