Expression, purification of influenza virus M2 protein without transmembrane domain and detection of its antigenicity

Objective To express and purify influenza virus M2 protein without transmembrane domain, and detect its antigenicity. Methods Full length M2 protein gene of A/PR/8/34(H1N1)was amplified from cDNA by RT-PCR and its transmembrane domain was deleted from 26 to 43 amino acid using two sets of primers, and then the mutated M2(sM2) gene was subcloned into expression vector pET30a. Fusion protein sM2 purified with the Ni 2+ chelating sepharose was used to vaccinate mice and detect antigenicity with the antiserum. Results sM2 fusion protein could be expressed effectively and recombinant fusion protein with high purity could be obtained after being purified with the Ni 2+ chelating sepharose. Immunofluorescence experiment indicated sM2 fusion protein possessed M2 immunogenicity. Conclusion The fusion protein sM2 lacking transmembrane domain of M2 (residue 26-43) had the same antigenicity as that of integrative M2 protein.