Stabilized virus like particles having enhanced mucosal immunogenicity

A method of producing an immune response in a subject, comprising the steps of:

• (i) preparing a dry powder immunogenic composition, wherein said composition consists of:
• a) viral protein subunits which can assemble into virus-like particles consisting of a norovirus capsid protein (NoVCP);
• and
• b) an anionic polysaccharide extracted from an aloe vera plant, wherein said VLPs are stabilized by the anionic polysaccharide at a pH over 6.5, and wherein the anionic polysaccharide has characteristics including a degree of methylation of 10% or less, a molecular weight >1×106 Daltons, an intrinsic viscosity from about 550 ml/g to about 978 ml/g, when dissolved in 0.1 M NaCl at a concentration of 0.0005-0.2% (w/v), a galacturonic acid content of at least 70%, a rhamnose content from about 2 to about 15% by mole, and capable of calcium gel formation when present at a concentration of 0.2% (w/v) in an aqueous solution comprising 2 mM calcium chloride;
• and
• (ii) intranasally inoculating the subject with the dry powder immunogenic composition to elicit an immune response, where said dry powder immunogenic composition does not include an adjuvant in addition to the anionic polysaccharide.