Mouse-adapted NS1 mutations enhance virus growth in untreated and in IFN-β primed mouse cells <i>in vitro</i>.

<p>Mouse M1 cells were untreated (left panel) or pre-treated with mouse IFN-β (1000 U/mL) for 24 hours (right panel), then infected in triplicate at an MOI of 0.02 with rHK NS mutants or rHK-wt virus, and supernatant collected 12, 24, 48, and 72 hpi was quantified for viral titre by plaque assay on MDCK cells. Graphical analysis of data was broken into three mutant sets, with rHK-wt included in each, due to the number of mutants surveyed. Data represent the means ± SD (*p<0.05, **p<0.01, ***p<0.001; two-tailed student's paired t-test for 12–72 hpi, indicated by horizontal bracket above time range).