Fig 4.

Chimeric protein expression, binding, and neuraminidase activity. (A) FACS analysis of cell surface expression from cells transfected with the chimeric proteins shown in Fig. 2. The results are presented as percentages of NDV HN cell surface expression. (B) Receptor binding in the absence (clear bar) or presence (black bar) of 2 mM zanamivir. The binding results are compared to NDV HN binding under the same conditions. (C) Neuraminidase activity of the receptor binding proteins, expressed in relative fluorescence intensity units (RFU) in the absence (clear bar) or presence (black bar) of 2 mM zanamivir. The neuraminidase results are compared to those for NDV HN and HPIV3 HN under the same conditions. The values are means ± SD of results from samples assessed in triplicate and are representative of the experiment repeated at least 4 times.