PEGYLATED LIPOSOMES FOR DELIVERY OF RNA ENCODING AN IMMUNOGEN

Abstract

Nucleic acid immunization is achieved by administering RNA encapsulated within a pegylated liposome. The RNA encodes an immunogen of interest. The PEG has an average molecular mass of between 1 kDa and 3 kDa. Accordingly, the invention provides a liposome having a lipid bilayer encapsulating an aqueous core, wherein: (i) the lipid bilayer comprises at least one lipid containing a polyethylene glycol moiety, such that the polyethylene glycol is on the exterior of the liposome, wherein the average molecular mass of the polyethylene glycol is between 1 kDa and 3 kDa' and (ii) the aqueous core contains an RNA encoding an immunogen. These liposomes are suitable for in vivo delivery of RNA to a vertebrate cell and are therefore useful as components of pharmaceutical compositions for immunizing individuals against various diseases.