Fig. 5

IFN-γ mRNA and protein expression were suppressed early but promoted by CS later during IAV infection. For CS groups, the mice were exposed to CS for 6 weeks in a smoke exposure chamber. Mice were infected with a non-lethal dose (300 pfu/mouse) of the IAV PR8 strain. Mock treated mice were inoculated with PBS. At the indicated time points, BALF was harvested for ELISA and lung tissues were collected for RNA preparation. a IFN-γ and related cytokine protein levels in BALF were determined by ELISA. b IFN-γ and related cytokine mRNA levels in the lung were assessed by qRT-PCR and normalized to β-actin.Data are expressed as means ± SEM. * denotes a significant difference between CS and NS groups at the same time point (P < 0.05, n = 4)