Figure 2

Inactivated influenza vaccine (IIV) formulated with ssRNA reduces viral replication and pathogenesis and induces protection against influenza virus. BALB/c mice were challenged with A/California/04/2009 virus 2 weeks after the boost schedule and sacrificed after 1 week as described in Fig. 1a. The lungs were harvested 1 week after the virus challenge, fixed, processed, and H&E-stained for lung histopathological evaluation. BALF was harvested 1 week after the challenge. The experimental groups are described in Fig. 1a. Data are represented as mean ± SD and statistically analyzed by one-way ANOVA and Student’s t-test. The significance of differences between groups are indicated by bars and symbols as follows: *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001. n = 5 mice for G1 to G6. Percentages of young and aged mice body weight (a) and clinical illness score (b) studied for 1 week after challenge with A/California/04/2009. Clinical illness score detailed in “Materials and methods”. (c) Viral titer in the lungs and BALF of young and aged mice measured by real-time PCR 1 week after challenge with A/California/04/2009. (d) Lungs were stained with hematoxylin and eosin (H&E). B, bronchus or bronchi; V, blood vessel; P, pulmonary emphysema; arrow, inflammatory cells (neutrophils and lymphocytes); arrowhead, hemorrhage; asterisk, exudate. (e) Percentages of pathological lesion area and total inflammatory score. (f) IL-4, IL-6, IL-10, IFN-γ, and TNF-α levels in BALF measured using the Magnetic Luminex Screening Assay Kit.