Background and purpose: Influenza virus is one of the most important respiratory infectious agents. Viral antigenic variations are major problems for vaccine production process. At present, many researches have focused on conserved domains of influenza virus antigenic peptides for subunit vaccine development. Hemagglutinin small subunit (HA2) and the 23 amino acid extracellular N-terminal domain of proton selective ion channel (M2e) are highly conserved in all human influenza A strains and very attractive for broad-spectrum universal influenza vaccine production.

Materials and methods: In this study, the synthetic 3M2e gene was cloned upstream of HA2 gene following digestion by BamH1. Chimeric construct pET28a-3M2e-HA2 was transformed into E.coli (BL21) and the cells were grown overnight in LB broth media containing 50 mg/ml kanamycin after induction of isopropyl-beta-D-thiogalactopyranoside (IPTG). Expression of chimer protein 3M2e-HA2 was approved by sodiumdodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and western blot analysis using monoclonal specific antibody. Then, the recombinant protein was purified using Ni-TED columns.

Results: The result of colony PCR, restriction enzyme digestion and sequencing revealed that the 3M2e gene was properly cloned into pET28a- HA2 and was in frame to histidin tag.

Conclusion: Identification of antibodies against conserved epitopes of (HA2) and (M2e) is an important step toward development of influenza vaccine, hence, chimer protein (3M2e-HA2) prepared in this study could be an appropriate subunit vaccine candidate for preventing influenza virus infection.