The development of a computationally optimized influenza HA protein that elicits broadly reactive immune response to all H5N1 influenza virus isolates is described. The optimized HA protein was developed through a series of HA protein alignments, and subsequent generation of consensus sequences, for clade 2 H5N1 influenza virus isolates. The final consensus HA amino acid sequence was reverse translated and optimized for expression in mammalian cells. Influenza virus-like particles containing the optimized HA protein are an effective vaccine against H5N1 influenza virus infection in animals.

The present invention provides a vaccine containing virus-like particles derived from virus particles having an envelope, in which a lipid-component content of the virus-like particles is reduced relative to a lipid-component content of the virus particles.

This disclosure provides compositions that include a mixture of viral like particles (VLPs), expressing different individual influenza hemagglutinin (HA) proteins that elicit broadly reactive immune responses to a wide variety of influenza viruses. For example, the composition can include at least two different influenza VLPs, a first VLP comprising a first HA polypeptide and a second VLP comprising a second influenza HA polypeptide, wherein the first and the second HA polypeptide are different subtypes and/or are from different influenza viruses, and a pharmaceutically acceptable carrier and/or an adjuvant. Methods of using the disclosed polymeric influenza VLP compositions to stimulate an immune response against influenza viruses, for example as a pre-pandemic or a seasonal vaccine, are provided.

A method for synthesizing influenza virus-like particles (VLPs) within a plant or a portion of a plant is provided. The method involves expression of influenza HA in plants and the purification by size exclusion chromatography. The invention is also directed towards a VLP comprising influenza HA protein and plant lipids. The invention is also directed to a nucleic acid encoding influenza HA as well as vectors. The VLPs may be used to formulate influenza vaccines, or may be used to enrich existing vaccines.

Compositions and methods to prepare influenza virus-like particles (VLPs) are provided.

A method for synthesizing influenza virus-like particles (VLPs) within a plant or a portion of a plant is provided. The method involves expression of a novel influenza HA protein in plants and its purification The invention is also directed towards a VLP comprising influenza HA protein and plants lipids. The invention is also directed to a nucleic acid encoding improved influenza HA as well as vectors. The VLPs may be used to formulate influenza vaccines, or may be used to enrich existing vaccines.

Provided is a method for efficiently proliferating an influenza virus serving as a material for vaccine in a host. A method for proliferating an influenza virus in a host, comprising a step of inhibiting transfer of Bax in a host cell to the inner mitochondrial membrane.

Disclosed herein are recombinant fusion protein comprising transmembrane domains, display polypeptides, and human oligomerization domains, and enveloped particles containing the same, and methods of use.

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.

Provided herein are chimeric influenza hemagglutinin (HA) polypeptides, compositions comprising the same, vaccines comprising the same, and methods of their use.