Construction Eukaryotic Expressing Vector Containing M2 Gene From Influenza A Virus And Its Immunoprotection

M2 protein of influenza A virus is a kind of highly conserved protein in amino acid sequence and possesses type specificity. Its ion channel activity can affect the structural stabilization of haemegglutinin (HA) and promote uncoating procedure. At present, M2 protein is considered as one of potential broad-spectrum vaccines for influenza A virus.Objectives To construct eukaryotic expression plasmid containing M2 gene from influenza A virus, and observe the immunoprotection in BALB/c mice vaccinated with the plasmid.Methods RNA was extracted from influenza virus which has been purified from allantoic fluid of chicken embryo inoculated with influenza virus A/PR/8/34 (H1N1) by absorption and release-RBC method. M2 gene was amplified by RT-PCR with specific primer and inserted into the eukaryotic expression vector pcDNA3.1(+) for constructing the recombinant plasmid pcDNA3.1(+)/M2. This plasmid was identificated by restrictive enzyme analysis, PCR and sequencing analysis. In order to study immunoprotection of the recombinant plasmid pcDNA3.1(+)/M2, we immunized healthy BALB/c (SPF) mice twice in a 3-week interval with the recombinant plasmid pcDNA3.1(+)/M2 at a dose of 100μg. One week after the second vaccination, the BALB/c mice were challenged with influenza A virus at 40 medial lethal dose (40×LD50). The virus titers of lung, survival rate, body weight change of BALB/c mice were observed and used for the evaluation of the immunoprotection induced by the recombinant plasmid...