An isolated expression enhancer active in a plant, portion of a plant or plant cell, the expression enhancer is provided. The isolated expression enhancer may be selected from the group consisting of nbEPI42 (SEQ ID NO:1); nbSNS46 (SEQ ID NO:2); nbCSY65 (SEQ ID NO:3); nbHEL40 (SEQ ID NO:4); and nbSEP44 (SEQ ID NO:5). Methods for using the isolated expression enhancer are also provided.

A method of producing a virus like particle (VLP) in a plant comprising modified H3 hemagglutinin is provided. The method comprises introducing a nucleic acid comprising a regulatory region active in the plant and operatively linked to a nucleotide sequence encoding a modified influenza hemagglutinin (HA) protein into the plant, or portion of the plant, the modified HA protein comprises a modified proteolytic loop. Followed by incubating the plant or portion of the plant under conditions that permit the expression of the nucleic acids, thereby producing the VLP. The modified proteolytic loop may comprise one or more protease cleavage sites exhibiting reduced or abolished cleavage by a protease. Also described is a virus like particle (VLP) produced by the method, and plants expressing the VLP. The virus like particle (VLP) may comprise plant-specific N-glycans, or modified N-glycans.

The present invention provides, among other things, a novel and improved method for generating “mosaic” influenza antigenic polypeptides including hemagglutinin (HA) and neuraminidase (NA) polypeptides based on unique combination of epitope patterns that maximize exposure to epitopes present across multiple HA or NA sequences and therefore improved influenza strain coverage. In particular, the present invention provides engineered H1N1 influenza hemagglutinin (HA) polypeptides that are comprised of novel combinations of protective epitopes and antigenic regions from multiple H1N1 viral strains. Such engineered HA polypeptides have improved properties over HA polypeptides developed through conventional approaches that rely on consensus alignments of viral sequences.

Provided herein are isolated mutant influenza hemagglutinin polypeptides, methods for providing isolated mutant hemagglutinin polypeptides, compositions comprising the same, vaccines comprising the same and methods of their use, in particular in the detection, prevention and/or treatment of influenza.

Disclosed are viruses, and vaccines comprised of and made from such viruses, that include a heterologous nucleic acid segment encoding α-1,3-galactosyltransferase (α-1,3-GT) such that the nucleic acid segment expresses α-1,3-GT when the virus infects a host cell. Such viruses produce proteins having α-1,3-galactose. The presence of α-1,3-galactose on proteins of infected cells can powerfully stimulate the immune response of the host against the viral proteins of the virus, thus enhancing the effect of the virus as a vaccine. Also disclosed are vaccines that include and/or are produced by such viruses. Also disclosed are methods of making and using such viruses and vaccines, such as administering to a subject in need thereof a vaccine as disclosed and such as making a vaccine that includes one or more viral proteins expressed by a virus as disclosed.

Disclosed herein are methods and exemplary compositions associated with antigen purification, exemplary aspects of which may include harvesting viral and antigenic substances from source organisms; and a purification platform comprising chemical separation and size-difference separation for the removal of contaminants, debris and impurities from the viral and protein (e.g. antigenic, including influenza hemagglutinin antigens) substances, as well as their concentration and collection.

Disclosed herein are nanoparticles suitable for use in vaccines. The nanoparticles present antigens from pathogens surrounded to and associated with a detergent core resulting in enhanced stability and good immunogenicity. Dosages, formulations, and methods for preparing the vaccines and nanoparticles are also disclosed.

Disclosed herein are methods and exemplary compositions associated with virus purification, antigen purification, and conjugation of virus and proteins (e.g., antigen) to form vaccines for delivery of immunological and other therapeutic agents, exemplary aspects of which may include harvesting viral and antigenic substances from source organisms; a purification platform comprising chemical separation and size-difference separation for the removal of contaminants, debris and impurities from the viral and protein (e.g. antigenic, including influenza hemagglutinin antigens) substances, as well as their concentration and collection; and a conjugation platform providing activation of the virus at a pH that increases binding rate and binding propensity between the virus and the protein, wherein embodiments related to the conjugation platform include controlling the ratio of virus to protein.

Recombinant constructs, influenza viral genomes including the recombinant constructs, influenza viruses including the constructs, and vaccine formulations formed thereof for inducing or increasing an immune response against influenza virus are provided. The compositions typically include a nucleic acid having a nucleic acid sequence encoding IgA-inducing protein (IGIP) polypeptide that can positively regulate IgA expression operably linked to expression of a hemagglutinin or a neuraminidase. When the nucleic acid is expressed by recombinant influenza virus in infected cells, it preferably enhances IgA production against influenza virus. Live attenuated virus expressing IGIP, and methods of use thereof for treating and preventing influenza infections are also provided.

The disclosure provides methods for generating an optimized nucleotide sequence encoding an engineered influenza structural protein and the optimized nucleotide sequences obtained therefrom. The optimized nucleotide sequences can be used in a reverse genetics system to facilitate the rescue of infectious influenza virus containing the engineered structural proteins and/or enhance viral titers. Also provided are methods of preparing an influenza vaccine composition using the optimized nucleotide sequences, as well as methods of inducing an immune response using the influenza vaccine composition.