Cationic liposomes are considered to be safe vectors for gene transfer
, but they are less efficient at delivering DNA to cells when compared
with retroviral vectors. Cationic liposomes complexed with DNA were t
argeted to specific cells in vitro by means of monoclonal antibodies (
mAbs) or ligands associated with the liposomes. Significant increases
in expression of a beta-galactosidase reporter gene were observed in v
itro in mAb-targeted liposomes, compared with non-targeted liposomes,
in both an adherent tumor cell line (human adenocarcinoma) and a suspe
nsion cell line (human T-lymphoma). Also, use of asialofetuin as a tar
geting ligand significantly increased expression of the reporter gene
in human hepatoma cells. Our results suggest that site-specific target
ing of cationic liposomes is a good strategy for increasing both the s
electivity and the efficiency of DNA delivery to cells and with furthe
r development may lead to targeted DNA delivery in vivo.