Prokaryotic expression of chimeric trimer protein (3M2e-HA2-NP) derived from conserved domains of influenza virus A/H1N1 as a promising universal subunit vaccine

Influenza A virus is an important respiratory pathogen which can cause high rates of morbidity and mortality during seasonal epidemics and pandemics. Current vaccines are not capable of producing effective immunity against different influenza virus subtypes. Designing universal vaccines using conversed domains of influenza virus antigens can overcome this limitation. The ectodomain of influenza M2 protein (M2e), the hemagglutinin stalk domain (HA2), and nucleoprotein (NP) are the most conserved sequences among subtypes of influenza A viruses. The aim of this study was to attach part of the NP gene into the binary structure of 3M2e-HA2 and assessment of expression of a chimer trimer protein in prokaryotic system. This recombinant protein is considered as a promising antigenic candidate for a universal vaccine production.
First, part of the NP gene segment of human influenza A/H1N1(PR/8/34)was amplified by PCR using designed specific primers. This amplified gene was cloned into pGEM-TEasy cloning vector. Then, the confirmed segment of NP gene was subcloned into PET28a/3M2e-HA2 recombinant expression vector, downstream of the HA2 segment. After confirmation of cloning, the chimer protein was expressed in E.coli BL21(DE3).
The results of colony PCR, restriction enzyme digestion and sequencing indicated that the NP gene segment was correctly cloned into PET28a/3M2e-HA2. Chimer protein expression was analyzed by SDS-PAGE and confirmed by Western blotting.
Design and production of recombinant protein (3M2e-HA2-NP) could be an important step towards the development of a universal influenza vaccine.