Fig. 4.

RIG-I mRNA and protein induction is impaired by CSE exposure during influenza infection, and whole lung viral replication may be enhanced. Mice were intratracheally treated with CSE for 6 wk and then infected with 300 pfu of the IAV PR8 strain. At day 7, the mice were killed, and lung tissues were collected for RNA and protein extraction. The RIG-I mRNA (A) levels were assessed by qRT-PCR normalized against β-actin, and RIG-I protein was determined by Western blot normalized to GAPDH (C). Influenza replication was assessed by measurement of viral nucleoprotein (NP) mRNA (B) levels normalized against β-actin mRNA. Mock-treated mice were inoculated with PBS. Data are expressed as means ± SE (4 mice/group). *Significant difference between CSE-treated PR8-infected and non-CSE-treated PR8-infected groups, P < 0.05.