The invention is directed to virus-like particles (VLPs) of an RNA bacteriophage that (a) comprises a coat polypeptide of said phage modified by insertion of a heterologous peptide that is displayed on said VLP and (b) encapsidates said bacteriophage mRNA as well as populations of these VLPs, and their uses. The invention is further directed to VLPs that encapsidate heterologous substances, as well as populations of these VLPs and their uses.
