Goat anti mouse igg conjugated with alexa fluor 568

Cells were fixed with 4% paraformaldehyde in PBS for 20 min at room temperature and washed with PBS. Cells were permeabilized with 0.1% Triton X-100 in PBS at room temperature for 5 min. After blocking with 3% non-fat dry milk for 30 min, cells were incubated with mouse monoclonal anti-influenza A nucleoprotein (AbD Serotec); bound antibodies were revealed with goat anti-mouse IgG conjugated with Alexa Fluor 568 (Molecular Probes). After washing, nuclei were stained with 1 μg ml⁻¹ 4′,6-diamidino-2-phenylindole (DAPI; Molecular Probes) in PBS for 15 min at room temperature. Fluorescent images were acquired on an Olympus IX70 microscope equipped with Nanomover and softWoRx DeltaVision image acquisition software (Applied Precision, WA, USA) and a U-PLAN-APO 60× objective. Images were captured under constant exposure time, gain and offset. To improve the contrast and resolution of digital images captured in the microscope, they were elaborated with deconvolution software.