Repeated exposure to cationic immunoliposomes activates effective gene transfer to human glioma cells.

The use of whole immunoglobulin G (IgG) and F(ab')2 of the G-22 monoclonal antibody associated with cationic liposomes (immunoliposomes) and the effect of repeated exposure were investigated for the transfection of the LacZ gene to various glioma cell lines. Immunoliposomes associated with either whole IgG or F(ab')2 monoclonal antibody caused an about 2-fold increase in beta-galactosidase activity compared with liposomes associated with no antibody in glioma cell lines expressing the CD44 antigen. beta-Galactosidase activity was further increased by about 2-fold by repeated exposure compared with single exposure. A glioma cell line not expressing the CD44 antigen showed no such increase in beta-galactosidase activity. These results indicate that repeated exposure of cationic immunoliposomes achieves a higher transfection efficiency and is a potentially effective method of gene therapy for patients with malignant glioma.