Research On The Immunogenicity Of H7N9 Oral Vaccine Based On Saccharomyces Cerevisiae Display Technology

Avian Influenza is an acute infectious disease caused by influenza A virus.Avian influenza virus has the characteristics of wide spread and high morbidity and mortality,which not only causes great losses to farmers,but also poses a great threat to human health.On March,2013,the first case of H7N9 infected human is reported.As an effective supplement to the traditional avian influenza vaccine production technology,H7N9 oral vaccine was constructed based on Saccharomyces cerevisiae（S.cerevisiae）surface display technology and its immunogenicity was investigated.The recombinant S.cerevisiae EBY100/pYD5-HA was constructed with pYD5 as the skeleton based on the hemagglutinin（HA）of A/Anhui/1-DEWH730/2013（H7N9）（Gen Bank ID:CY187618）as the research object.Specific expression of HA protein was detected by Western blot analysis;The expression position of HA protein and display efficiency were determined by immunofluorescence labeling and flow cytometry analysis;The expression of HA protein in the recombinant S.cerevisiae EBY100/pYD5-HA was quantified by indirect ELISA.SPF BALB/c mice were used as animal models to investigate the immunogenicity of recombinant S.cerevisiae EBY100/pYD5-HA after oral administration.The specific serum Ig G titer induced by recombinant S.cerevisiae EBY100/pYD5-HA and the secretion level of IFN-γ/IL-4 were detected by ELISA and ELISpot,respectively;The HI experiment was used to detect the titer of neutralizing antibody induced by recombinant S.cerevisiae EBY100/pYD5-HA.H7N9 HA protein can be stably and efficiently expressed on the surface of recombinant S.cerevisiae EBY100.1OD_600nmof recombinant S.cerevisiae EBY100/pYD5-HA expressed 10μg of HA protein.Furthermore,recombinant S.cerevisiae EBY100/pYD5-HA can induce significant humoral immune response,cellular immune response and serum HI titer after oral immunization of BALB/c mice,which provides important data support for evaluating the immunogenicity of recombinant S.cerevisiae EBY100/pYD5-HA.The establishment of this universal technology platform will provide a strong guarantee for the prevention and control of avian influenza in the world,and also provide new ideas and strategies for the design and development of other important and severe infectious diseases oral vaccines.