Evaluation of mRNA lipoplexes prepared using modified ethanol injection method as a tumour vaccine.

We have previously demonstrated that messenger RNA (mRNA) lipoplexes composed of -hexadecyl-,-dimethylhexadecan-1-aminium bromide (DC-1-16), 1,2-dioleoyl--glycero-3-phosphoethanolamine (DOPE), and polyethylene glycol-cholesteryl ether (PEG-Chol) exhibited high protein expression in the lungs and spleen of mice after intravenous injection and induced high levels of antigen-specific IgG1 upon immunisation. In this study, we optimised PEG modification in mRNA lipoplexes to reduce mRNA accumulation in the lungs and evaluated the suppression of tumour growth in mice bearing mouse lymphoma E.G7-ovalbumin (OVA) tumours by immunising them with an intravenous injection of OVA mRNA lipoplexes.