A broad protection provided by matrix protein 2 (M2) of avian influenza virus.

To prevent a future influenza A virus subtype pandemic outbreak, developing a broad-spectrum vaccine would be highly beneficial. The ion channel protein M2 is highly conserved in a diverse number of influenza A virus subtypes. This distinguishing characteristic makes M2 an attractive vaccine target for a broadly protective vaccine. We expressed a full-length M2 protein which was C-terminally fused to a small peptide in Escherichia coli. Because this recombinant M2 (rM2) protein forms multimeric complexes with high molecular weight, it serves as a potential immunogen. Antibodies induced by the rM2 protein prevented the replication of different subtypes of influenza A virus both in vitro and in vivo. Animal study demonstrated that rM2 immunization protected mice against influenza A virus infection via limiting replication of virus progeny in vivo and attenuating lung damage. As such, the M2 protein is a highly potential candidate for next generation vaccine development with the capability of protecting against various influenza A virus subtypes.