Influenza virus-like particles (VLPS) comprising hemagglutinin

A method of producing influenza virus like particles (VLPs) in a plant said method comprising:

• a) providing a plant, or a portion of a plant, comprising a nucleic acid introduced by agroinfiltration, the nucleic acid comprising a nucleotide sequence encoding an influenza hemagglutinin (HA) and having at least 80% sequence identity to the sequence of HA of type A/California/04/09 as defined by nucleotides 52 to 1701 of SEQ ID NO:135, the nucleotide sequence operatively linked to a regulatory region active in a plant, the regulatory region comprising Cowpea Mosaic Virus (CPMV)-HT, and the HA comprising a native HA signal peptide or a non-native HA signal peptide, the HA having hemagglutinin activity as determined by using a hemagglutination assay;
• b) incubating the plant or portion of the plant under conditions that permit the expression of the nucleic acid, thereby producing the VLPs, wherein the nucleic acid is transiently expressed in the plant or portion of the plant;
• and
• c) harvesting the plant and purifying the VLPs.