OBJECTIVETo understand if the Neuraminidase (N1) of Influenza A virus at the surface of yeast-displaying system, eukaryotic expression system and the infected cells could be used for anti-NA Abs screening, their activities and bindings to five candidate Abs were assayed.

METHODSThe surface NA expression was obtained by transfecting by recombinant NA constructors with specific tag-labels or live virus infection. The functional activity was measured by the fluorescent assay. Their bindings to the Abs were detected by flow cytometry.

RESULTSThe surface NAs presenting on the yeast-displaying system and eukaryotic expression system exhibited functional NA activities as the NA at the surface of virus-infected cells which showed affinities to Ab1, 4, and 5. The same bindings to Abl and 5 were found in the surface NA expressed by eukaryotic expression system while minor binding was observed in the yeast displayed-NA.

CONCLUSIONThe epitopes of yeast-displayed NA may be different from the NAs present at eukaryotic expression system and the infected cells which more likely suitable for the screening of anti-NA Abs.