Fig 1.

Detection of influenza A virus NP on the surface of influenza virus-infected A549 cells, B cells, and MDCK cells by MoAb NP. Cells were infected with influenza virus RESVIR-9 (H3N2) at an MOI of 3 (white) or not infected (gray) and after 16 to 18 h of incubation subsequently incubated with MoAb NP or isotype control antibody (20 μg/ml) as indicated, and binding of these antibodies was assessed after subsequent incubation with an FITC-labeled MoAb directed against human IgG by flow cytometry (A) or confocal microscopy (B).