Figure 3.
Cell-binding assay to show binding of (A) pH1N1 and (B) H3N2 pre-incubated with rfhSP-D to A549 cells. Microtiter wells were coated with A549 cells (1 × 105 cells/ml) and incubated overnight at 37°C. Varied concentrations of pre-incubated rfhSP-D (10, 5, 2.5, and 1.25 µg/ml) with pH1N1 and H3N2 virus were added to the corresponding wells, followed by incubation at room temperature for 1–2 h. After fixing the cells with 4% paraformaldehyde solution, monoclonal anti-influenza virus H1, or polyclonal anti-influenza virus H3 were added to corresponding well. Maltose-binding protein (MBP) was used as a negative control protein. The data were expressed as mean of three independent experiments done in triplicates ± SEM.