Yeast surface displayed influenza vaccines

A potential global influenza pandemic poses significant challenges to the conventional egg-based vaccine production technologies due to their limited productivity and high cost. This study proposes a new technology capable of massive production of influenza vaccines at low cost. This technology was based on a yeast cell surface protein display system developed in our previous work. This new vaccine was developed by displaying influenza H5N1 HA proteins on the surface of yeast in such a manner that the administration of the HA displayed yeast will provide complete protection from influenza virus infection. Two vaccines: i.e., EBY100/pY2HA1 and EBY100/pY2HAS, were developed and tested for their immunogenicity in animal studies. HA1 contains only the HA1 sub-unit of the HA; whereas HAS entails both HA1 and HA2 subunits but not the transmembrane and topological domains of the HA. The HA secretion signal peptide sequence was deleted from both constructs. A yeast a-agglutinin protein anchoring system was used to display both the HA1 and HAS on the surface of Saccharomyces cerevisiae. The surface display of these antigens was induced by galactose. The surface display of the HA antigens was determined through confocal fluorescence microscopy, flow cytometry, Western blot, and cell fractionation analysis. The glycosylation of surface displayed HAs was also confirmed. The animal studies revealed the elicitation of anti-HA antibody production in heat-killed recombinant yeast vaccinated mice. These results showed the promising of this new technology for massive production of influenza vaccines at low cost.;Keywords: Influenza vaccine, whole yeast vaccine, antigen-based vaccine, and cell surface protein display.