Fig 7.

Stalk domains of chimeric receptor binding proteins confer specificity of fusion promotion. 293T cells coexpressing HPIV3 F (A), NiV F (B), or NDV F (C) with the indicated receptor binding proteins (listed on the x axis) were allowed to bind to receptor-bearing RBCs at 4°C in the absence (white bars) or presence (dark bars) of zanamivir. Zanamivir was added to activate NDV HN site II. Values on the y axis reflect quantitation of RBCs that fused with the glycoprotein-expressing cells. The values are means ± SD of results of three experiments performed in triplicate.