Binding of choleragen and anti-ganglioside antibodies to gangliosides incorporated into preformed liposomes.
Exogenously added gangliosides were taken up and incorporated into liposomes just as they are incorporated into cells. Ganglioside GM1 was rapidly taken up by liposomes containing dimyristoyl- or dipalmitoylphosphatidylcholine, cholesterol and dicetyl phosphate. When incubated with a wide range of GM1 concentrations for 18 h, the liposomes incorporated about 10% of the added ganglioside. The rate of GM1 uptake by preformed liposomes was both time- and temperature-dependent. The liposomes also incorporated other gangliosides to a similar extent. The GM1 taken up by preformed liposomes was predominantly located on the outer surface of the liposomes and did not appear to be internalized into the inner half of the lipid bilayer. Liposomes containing GM1 added after liposome formation bound as many anti-GM1 antibodies and as much choleragen as liposomes having GM1 added during the formation of the lipid bilayers. Thus, preformed liposomes sensitized by incubation with GM1 are a good model system for studying the interactions of antibodies and toxins with membrane-associated gangliosides.
D000906:Antibodies; D000936:Antigen-Antibody Complex; D002772:Cholera Toxin / Q000378:metabolism*; D005677:G(M1) Ganglioside / Q000276:immunology / Q000378:metabolism*; D005732:Gangliosides / Q000378:metabolism*; D007700:Kinetics; D008081:Liposomes; D008954:Models, Biological; D009439:Neuraminidase; D010713:Phosphatidylcholines; D011485:Protein Binding; D014734:Vibrio cholerae
D000906:Antibodies; D000936:Antigen-Antibody Complex; D005732:Gangliosides; D008081:Liposomes; D010713:Phosphatidylcholines; D005677:G(M1) Ganglioside; D002772:Cholera Toxin; D009439:Neuraminidase