Addition of αGal HyperAcute™ technology to recombinant avian influenza vaccines induces strong low-dose antibody responses

Highly pathogenic avian influenza represents a severe public health threat. Over the last decade, the demand for highly efficacious vaccines against avian influenza viruses has grown, especially after the 2013 H7N9 outbreak in China that resulted in over 600 human cases with over 200 deaths. Currently, there are several H5N1 and H7N9 influenza vaccines in clinical trials, all of which employ traditional oil-in-water adjuvants due to the poor immuno-genicity of avian influenza virus antigens. In this study, we developed potent recombinant avian influenza vaccine candidates using HyperAcute (TM) Technology, which takes advantage of naturally-acquired anti-alpha Gal immunity in humans. We successfully generated alpha Gal-positive recombinant protein and virus-like particle vaccine candidates of H5N1 and H7N9 influenza strains using either biological or our novel CarboLink chemical alpha Gal modification techniques. Strikingly, two doses of 100 ng alpha Gal-modified vaccine, with no traditional adjuvant, was able to induce a much stronger humoral response in alpha GT BALB/c knockout mice (the only experimental system readily available for testing alpha Gal in vivo) than unmodified vaccines even at 10-fold higher dose (1000 ng/dose). Our data strongly suggest that alpha Gal modification significantly enhances the humoral immunogenicity of the recombinant influenza vaccine candidates. Use of aGal HyperAcute (TM) technology allows significant dose-sparing while retaining desired immunogenicity. Our success in the development of highly potent H5N1 and H7N9 vaccine candidates demonstrated the potential of alpha Gal HyperAcute (TM) technology for the development of vaccines against other infectious diseases.