Flow cytometric analysis of immune cells in lungs showed an increase of macrophages and granulocytes after infection.

<p>Female C57BL/6J mice were infected with 2×10³ FFU PR8 (H1N1) virus and cellular infiltrates were determined by flow cytometry. The total number of granulocytes and macrophages strongly increased after infection. Absolute numbers were determined based on a standard curve of CD45⁺ cells after influenza infection equalizing the individual measurements to the same amount acquired.