Fig 9.

Mutation at NDV HN site II abolishes the ability of chimeric receptor binding proteins to promote fusion. 293T cells coexpressing NiV F with NiV-NDV R516A chimeric binding protein (A and B) or expressing HPIV3 F with HPIV3-NDV R516A chimeric binding protein (C and D) were allowed to bind to receptor-bearing RBCs at 4°C in the absence (A and C) or presence (B and D) of zanamivir. Values on the y axis reflect quantitation of RBCs that were released, bound, or fused at the time points of incubation at 37°C indicated on the x axis. The values are means ± SD of results from triplicate monolayers from a representative experiment, repeated at least 3 times.