Sendai virosomes revisited: Reconstitution with exogenous lipids leads to potent vehicles for gene transfer

A reliable new procedure is described for the reconstitution of Sendai vira l envelopes suitable for gene transfer. Both fusion and hemagglutinin-neura minidase glycoproteins were extracted from purified Sendai virus and recons tituted together with DNA in the presence of cholesterol:sphingomyelin:phos phatidylcholine:phosphatidylethanolamine (Chol:SM:PC:PE) In a molar ratio o f 3.5:3.5:2:1. Before reconstitution, the DNA to be transferred was condens ed by pretreatment with polylysine. Exogenous lipid addition and the DNA-co ndensation step were essential for maximal size as well as for fusogenic ac tivity of the resulting virosomes, the analysis of which revealed (1) the a bsence of any genomic material originating from Sendai virus, (2) the prese nce of fusogenic spikes in a functional orientation, (3) the encapsulation of reporter genes, and (4) high-transfer activity for plasmids carrying the green fluorescent protein (GFP) gene and double-stranded nucleotides into different mammalian cells. Transfer rates were up to 10-fold higher than th ose obtained with different cationic lipids. Gene delivery by means of our lipid-enriched Sendai virosomes extends the known gene transfer strategies, including those based on Sendai virus previously published. (C) 2000 Acade mic Press.