Figure 1.

Inhibition of influenza virus infection by λ-CGN in vitro. (A) Chemical structure of the repeating disaccharide unit in λ-CGN. (B) Western blot analysis showing expression of viral proteins. MDCK cells infected with PR8 at an MOI of 0.001 were mock-treated (Mock) or treated with 10 μM of OSV-C or with increasing concentrations of λ-CGN or p-KG03 at 35 °C. On the next day, cell lysates were harvested for SDS-PAGE and immunoblotting with anti-NP or anti-HA antibodies. β-Actin was used as a loading control. ‘No virus’ means negative control without viral infection. Proteins are indicated on the right side of the panels. (C) Plaque assay to determine viral titers. Serial ten-fold dilutions of cell culture supernatants acquired after viral infection and compound treatment in (B) were loaded onto fresh MDCK cells and cultured at 33 °C in 1.2% Avicel-containing overlay medium. The number of viral plaques was counted after crystal violet staining on day 3 post-infection. Data are expressed as the mean ± S.D. of three independent experiments. ****P < 0.0001. The graph was created using GraphPad Prism 8.3.1 (www.graphpad.com).