Introduction of liposome sequestered human hexosaminidase A and ferritin into lysosomes of mouse macrophages

Homogeneous hexosaminidase A and ferritin were sequestered in liposomes consisting of lecithin (phosphatidyl choline), dicetyl phosphate and cholesterol in the molar ratio of 7 : 2 : 1. These liposomes were coated with heat aggregated IgG and presented to mouse macrophages harvested from the peritoneal cavity. The infiltration of macrophages in the peritoneal cavity was accomplished by injection of 5% oyster glycogen. The cells were pelleted, fixed, embedded, and sections were examined under the electron microscope. Evidence is presented ted that the liposomes coated with heat aggregated IgG, are phagocytised by the macrophages and enter into the lysosomes. The ferritin is deposited exclusively in the lysosomes, a result that enhances the efficacy of liposomes as carriers of enzymes in enzyme replacement therapy in lysosomal storage disorders.