Methods of making hemagglutinin proteins

A method of making an immunogenic fusion protein, comprising the steps of:

• a) transforming a nucleic acid encoding a fusion protein into a eukaryotic host cell, wherein the eukaryotic host cell is not a Pichia pastoris eukaryotic host cell, the fusion protein including,
• i) at least a portion of a flagellin that initiates an intracellular signal transduction pathway for a Toll-like Receptor, and
• ii) a portion of an influenza viral hemagglutinin, wherein the portion of the influenza viral hemagglutinin lacks
• a transmembrane domain,
• a cytoplasmic domain;
• and
• an HA2 subunit,
• and includes,
• at least a portion of a globular head, and
• at least a portion of at least one secondary structure having at least one β-sheet at a bottom of the globular head that causes the globular head to essentially retain its tertiary structure;
• and
• b) culturing the eukaryotic host cell to thereby make the immunogenic fusion protein.