THE INFLUENCE OF ENDOSOME-DISRUPTIVE PEPTIDES ON GENE-TRANSFER USING SYNTHETIC VIRUS-LIKE GENE-TRANSFER SYSTEMS

The process by which viruses destabilize endosomal membranes in an aci dification dependent manner has been mimicked with synthetic peptides that are able to disrupt liposomes, erythrocytes, or endosomes of cult ured cells. Peptides containing the 20 amino-terminal amino acid seque nce of influenza virus hemagglutinin as well as acidic derivatives sho wed erythrocyte lysis activity only when peptides were elongated by an amphipathic helix or by carboxyl-terminal dimerization. Interestingly , peptides consisting of the 23 amino-terminal amino acids of influenz a virus hemagglutinin were also active in erythrocyte lysis. When pept ides were in corporated into DNA complexes that utilize a receptor-med iated endocytosis pathway for uptake into cultured cells, either by io nic interaction with positively charged polylysine-DNA complexes or by a streptavidin-biotin bridge, a strong correlation between pH-specifi c erythrocyte disruption activity and gene transfer was observed. A hi gh-level expression of luciferase or interleukin-2 was obtained with o ptimized gene transfer complexes in human melanoma cells and several c ell lines.