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