Soluble expression of influenza virus M2 protein and detection of its antigenicity
Influenza virus M2 is a protective as well as a highly conservative protein, so it is a suitable candidate for cross protective vaccine. In this study, we cloned M2 gene from A/PR/8/34 virus infected MDCK cells, and deleted its transmembrane domain in order to obtain high level expression. Then the mutated M2(sM2) was subcloned into the expression vector pET-32a. The recombinant plasmid could express sM2 fusion protein in a soluble form. Further, it was purified by ammonium sulphate precipitation combined with affinity chromatography. Sera collected from the mice that were immunized with the purified fusion protein could bind to influenza virus infected MDCK cells testified by immunofluorescence experiment. This indicates that the expressed fusion protein possesses M2 antigenicity.