Fig 6.

NDV HN site II is required for F activation. 293T cells coexpressing NiV F with the NiV-NDV chimeric binding protein (A and B) or expressing HPIV3 F with the HPIV3-NDV 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. Zanamivir was added to activate NDV HN site II. 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.