In order to express the recombinant Neuraminidase（NA） protein of avian influenza virus Hubei strain

A/chicken/Hubei/489/2004（H5N1）

a truncated na gene fragment was amplified by PCR with pMD-NA plasmid（GenBank No.AY770078） as template.After digestion with EcoRⅠand HindⅢ

the PCR product was cloned into pET-28a vector and the recombinant plasmid pET-28/ΔNA was analyzed by restriction enzyme digestion and sequencing

and then was transformed into E coli BL21-CondonPlus（DE3）-RIL.A truncated NA protein fused with the polyhistidine tag in N-terminal was expressed by the induction of IPTG and identified by SDS-PAGE and Western blot analysis.Polyclonal antibody against the NA protein was prepared after injected rabbit with the purified recombinant NA protein.The results from ELISA and indirect immunofluorescence indicated the antibody has high titer and excellent specificity for avian influenza virus H5N1 NA protein.These results might be contributive to develop the candidate NA subunit vaccine against avian influenza virus H5N1 subtype and detect virus infection.