Abstract
We have developed fusogenic liposomes, prepared by fusing simple liposomes and Sendai virus particles. Fusogenic liposomes can introduce their contents directly and efficiently into the cytoplasm in vitro and in vivo. In this study, we examined the characteristics of fusogenic liposomes as a gene transfer vector. Fusogenic liposomes could transfer genes into cultured cells more efficiently than cationic liposome-DNA complex. When the cells were treated with fusogenic liposomes containing pCAL2, a firefly luciferase expression plasmid, for 1-10 min, they had high luciferase activity. In contrast, the cells transfected with cationic liposome-DNA complex had little activity. In addition, fusogenic liposomes showed no cytotoxicity even at higher concentration of DNA. Furthermore, when fusogenic liposomes containing 0.75 μg of pCAL2 was i. p. injected into the mouse bearing Sarcoma-180 ascites tumor, a high level of luciferase activity was detected in Sarcoma-180 cells. In contrast, little luciferase activity was detected even when cationic liposome-DNA complex containing 40 μg of pCAL2 was administrated. These results indicates that fusogenic liposomes mediate efficient gene introduction into the animal cells in vitro and in vivo.
