An affinity-conjugated antigen system (ACAS) comprising one or more antigens conjugated via a plurality of affinity moieties to a papaya mosaic virus (PapMV) or virus-like particle (VLP) derived from the coat protein of PapMV is provided. The affinity moieties are molecules or compounds that are capable of specifically binding to the antigen(s) of interest and which can be attached, for example by chemical or genetic means, to the coat protein of the PapMV or PapMV VLP. The ACAS can optionally further comprise one or more additional antigens, which may be the same as, or different to, the conjugated antigen(s) comprised by the ACAS. Also provided are immunogenic compositions, including vaccines, comprising an ACAS. The immunogenic compositions are useful in the treatment, including prevention, of various diseases and disorders for which a humoral and/or cellular response in the animal is required.
