Immunostaining of swine PCLS infected by swine influenza A viruses. PCLS were infected by subtypes H1N1 (H1N1/1981), H1N2 (H1N2/2000) and H3N2 (H3N2/2007) swine influenza viruses. Cryosections were prepared at 24 hpi and used for detection of infected cells, ciliated cells, and mucus-producing cells. Infected cells were stained with anti-nucleoprotein (NP) antibody; ciliated cells were stained using anti-β-tubulin antibody (red) and mucus-producing cells were stained using anti-Muc5Ac antibody (green). A, control slices showing ciliated and mucus-producing cells; B, co-staining of ciliated and virus-infected cells; C, co-staining of mucus-producing cells and virus-infected cells. Nuclei were stained with 4′,6-diamidino-2-phenylindole (DAPI).