Figure 3

Histochemical visualization of virus-infected cells by using the BTP3-Neu5Ac assay.

(a) MDCK cells were infected with avian influenza A virus strain A/duck/Hong Kong/313/4/1978 (H5N3) at a multiplicity of infection (MOI) of 0.01 to 1. After culture for 12 hr, the infected cells were incubated with 10 μM BTP3-Neu5Ac at 37°C for 10 min. (b) MDCK cells were infected with A/duck/Hong Kong/313/4/1978 (H5N3) and cultured for 12 hr. The infected cells were incubated with 10 μM BTP3-Neu5Ac in the absence or presence of zanamivir at 37°C for 10 min. (c) MDCK cells were infected with A/duck/Hong Kong/313/4/1978 (H5N3) and cultured for 10 hr. The infected cells were fixed with 4% paraformaldehyde-PBS and immunostained with mouse anti-NA monoclonal antibody (red). Then the immunostained cells were incubated with 10 μM BTP3-Neu5Ac at 37°C for 3 min (green). (d) MDCK cells were infected with influenza A virus strains [A/PR/8/1934 (H1N1), A/Memphis/1/1971 (H3N2) and A/Shizuoka/833/2009 (H1N1pdm)] and influenza B virus strain (B/Lee/1940). After culture for 12 hr, the infected cells were incubated with 10 μM BTP3-Neu5Ac at 37°C for 10 min. Scale bars indicate 200 μm.