The Role of Neutrophils during Mild and Severe Influenza Virus Infections of Mice
Figure 3
Neutrophils are not susceptible to influenza virus infection.
Mature murine neutrophils were purified from the bone marrow as described in Materials and Methods. Aliquots of 106 (i) LA-4 epithelial cells, or (ii) neutrophils were incubated with 107 PFU of BJx109, HKx31 or PR8. Control cells were incubated with BJx109 that had been UV-inactivated to destroy virus infectivity (UV BJx109). After 1 hr, cells were washed and incubated an additional 8 hrs. (A) Cells were fixed and levels of intracellular viral NP protein determined by flow cytometry. Histograms shown represent cells incubated with virus (grey) or uninfected control cells (white). A gate was set to include 5% of cells in the uninfected control and the percentage of cells staining positive for intracellular NP are shown relative to this in each panel. (B) RNA was extracted from cells and levels of (i) vRNA and (ii) mRNA encoding NP, PA and M genes determined via quantitative RT-PCR. Cells incubated in media alone (mock) were included as a control. Data is expressed in pg/ml and represent the mean ± SD of 3 independent experiments.