A single N66S mutation in the PB1-F2 protein of influenza A virus increases virulence by inhibiting the early interferon response in vivo. Mus musculus

This study used virological, histological, and global gene expression from an experimental murine model of influenza infection to study the contribution of a specific mutation in the PB1-F2 protein (PB1-F2 N66S) of influenza A to viral pathogenesis. Overall design: 6-8 week old, wild-type, female, C57Bl/6 mice were inoculated individually with 30 μl (10^4 PFU) of virus (recombinant influenza A/WSN/33 carrying the PB1 gene segment from A/Hong Kong/156/97 (H5N1) or a PB1 mutant recombinant virus resulting in an amino acid change at position 66 in the PB1-F2 protein [N66S]) in phosphate-buffered saline (PBS) containing penicillin-streptomycin and bovine serum albumin (PBS-BA-PS). A total of 10^4 PFU of virus was given in all inoculations. Control mice were given PBS-BA-PS. Lung samples were taken for microarray analysis at 12h, 1d, 3d, and 5d post-infection (n=3 animals per group at each time point for virus infected animals; n=2 animals per time point for mock-infected animals).