Figure 2. Induction of antiviral immune responses and viral clearance are not impaired in the presence of Mtb.

C57BL/6 mice were infected via aerosol with a low dose of Mtb H37Rv and 12 days later coinfected i.n. with 1 × 10⁴ PFU IAV (A/HH/05/09 H1N1). Lungs collected at indicated time points were analyzed for (A) the activity of type I/III IFN and (B) Mx1 expression by qRT-PCR relative to Gapdh expression (n = 4 per group, representative of 2 independent experiments). (C) Shows total lung CD8⁺ T cell numbers and frequencies among CD45⁺ cells (n = 4 per group, representative of 2 independent experiments) and (D) H1N1-NP366 dextramer–specific CD8⁺ T cells (n = 5 per group, 1 experiment). (E) Viral titers were determined by MDCK plaque assay (n = 3–4 per group, representative of 4 (day 3 and day 6) and 2 (day 9) independent experiments). (A and B) Data are represented as mean + SD or (C–E) each point representing 1 mouse. *P ≤ 0.05; **P ≤ 0.01, ***P ≤ 0.001 determined by (A–D) 1-way ANOVA followed by Tukey’s multiple-comparison test and (E) unpaired t test.