FIGURE 4:

Productive infection by MRV particles following uptake at the apical surface of polarized MDCK cells. (A) The assay procedure, as detailed in Materials and Methods, is depicted schematically. MDCK cells were seeded 5 d before infection to allow complete polarization. (B) Top, representative fields of polarized MDCK cells subjected to the infection assay with virions or ISVPs in the absence or presence of inhibitors as indicated. Immunostained μNS protein, indicative of productive infection, appears green. Bottom, the number of infected cells in the presence of each inhibitor was assessed by μNS immunostaining and normalized to the number of infected cells in mock-treated samples. Data are shown as the mean value ± SD from at least 10 fields in each of three independent experiments.