DESIGN OF IMMUNOLIPOSOMES DIRECTED AGAINST HUMAN OVARIAN-CARCINOMA

Factors (protein/lipid ratio, pH of incubation medium, incubation time , anchor molecule density in the bilayer) affecting the covalent bindi ng of anti-ovarian carcinoma Fab' to liposomes containing the anchor m olecule MPB-PE -maleimidophenyl)butyryl)phosphatidylethanolamine) were explored. Standard experimental conditions were chosen and informatio n on the relevant physicochemical parameters of the liposome dispersio ns was collected (mean particle diameter, size distribution, charge). The reproducibility of standard immunoliposomes prepared in subsequent batches in terms of Fab' binding, particle size and charge was establ ished. In addition, preservation of immunoreactivity, no marker loss, and no aggregation/fusion was found for the standard immunoliposomes o ver a period of at least 3 weeks at 4 degrees C. In vitro up to 35000 immunoliposomes were estimated to bind per human ovarian carcinoma cel l. Internalization of the immunoliposomes could not be demonstrated. E lectron micrographs showed binding of specific immunoliposomes to huma n ovarian carcinoma cells growing intraperitoneally in athymic nude mi ce.