Fig 1.

Study design. Schematic overview of the study. The time scale represents the number of days (d) after the initial inoculation with DMEM, M2, or WT. Eight mice in each group were sacrificed at 5, 14, 28, and 56 days p.i. At 28 and 56 days p.i., mice in six groups were challenged intranasally with 100 μl of 10⁷ PFU of recombinant NL/1/00 or NL/1/99. Five days later, the animals were sacrificed.