Figure 3. Percentages of NK cells and expression of NKp46 and CD25 in lung tissue.

Mononuclear cells were isolated from lung tissue of pigs infected with influenza A virus (n = 12) and control animals (n = 6) during the first 3 days pi and analysed by flow cytometry. (A) Live CD3⁻ lymphocytes were gated as described in Fig 2. NK cells were gated according to CD8α and NKp46 expression and defined as NKp46⁻, NKp46^int or NKp46^high cells. Plot shown is from a representative control animal. (B) Proportions of NKp46⁻ (green), NKp46^int (blue) and NKp46^high (purple) NK cells in individual animals, shown as percentages of gated cells in lymphocytes. (C) Percentages of NKp46⁻ (left), NKp46^int (middle) and NKp46^high (right) NK cells among lymphocytes. (D) Median fluorescence intensity (MFI) in the NKp46⁻ gate (left), the NKp46⁺ gate (middle) and in the NKp46^high gate (right) are shown. (E) CD25⁺ cells were gated in the NKp46⁻ and NKp46^int NK cells (left) and in the NKp46^high NK cells (right). Plots shown are from a representative control animal. (F) The percentages of CD25⁺ cells in each gate were calculated in control animals (green), infected animals from day 1 (purple), day 2 (blue) and day 3 (pink) pi. *p≤0,05, **p≤0.01.