Abstract: This invention is directed to diagnostic methods detecting the presence of an antibody to a virus in a sample from a subject and kits for using the methods.

Abstract: The specification discloses chimeric or recombinant virus-like particles comprising (i) S polypeptide of an avian hepadnavirus and (ii) a chimeric fusion protein comprising a polypeptide of interest covalently attached to a particle-associating portion of L polypeptide of an avian hepadnavirus, wherein the polypeptide of interest comprises a transmembrane domain or a protein binding domain or motif and wherein the chimeric fusion protein further comprises a second or further polypeptide of interest comprising a transmembrane domain and/or a protein binding domain or motif, wherein the second or further polypeptide is associated with the virus-like particle via non-peptide bonds. It is proposed that such VLPs more closely resemble the naturally occurring configuration of antigenic complexes or pathogens. The chimeric virus-like particles are illustrated using viral envelope proteins from measles, hepatitis C virus, influenza A and HIV and by polyproteins from Plasmodium surface proteins.

Abstract: The present invention provides a virus-like particle (VLP) comprising i) a polypeptide comprising a polypeptide of interest (POI) and at least a particle-associating portion of a large envelope (L) polypeptide of an avian hepadnavirus or a functional derivative or homolog thereof, and ii) a small envelope (S) polypeptide of an avian hepadnavirus or a functional derivative or homolog thereof. By introducing one or more POIs into the L polypeptide, the POI is translocated along with L into a particle structure made up primarily of S polypeptide. The present invention furthermore provides methods for producing a recombinant virus-like particle.