An alternative procedure for the preparation of immunogenic liposomal model membranes.
This investigation describes a new procedure for the preparation of immunogenic liposomes which circumvents the need to synthesize the N-(hapten)-substituted derivatives of phosphatidylethanolamine that were previously employed for this purpose. The method is based on the generation of liposomes containing the N-hydroxysuccinimide (NHS) esters of either palmitic acid, cholesteryl-hemisuccinate, or N-succinyl-phosphatidylethanolamine. Reaction of these preformed liposomes with a hapten that possesses a substitutable amino group (e.g., DNP-lysine) results in covalent attachment of the hapten to the lipid bilayers. As a consequence of this binding, the liposomes can elicit formation of hapten-specific plaque-forming cells in mice. The reliability of this procedure is indicated by the fact that these liposomes share the essential immunological properties of liposomes sensitized by incorporation of N-substituted phosphatidylethanolamine derivatives (e.g., DNP-Cap-PE). Thus, the magnitude of the response was found to be dependent on: (a) the presence of lipid A in the liposomes; (b) the phospholipid composition of the liposomes; (c) the distance separating the DNP determinant from the liposomal surface. Additional applications of liposomes, which contain the NHS esters, are indicated.
D000818:Animals; D000921:Antibody-Producing Cells / Q000276:immunology; D000941:Antigens / Q000276:immunology*; D001666:Binding Sites, Antibody; D004136:Dinitrobenzenes / Q000276:immunology; D005260:Female; D006241:Haptens / Q000276:immunology; D006462:Hemolytic Plaque Technique; D007158:Immunologic Techniques; D008081:Liposomes / Q000276:immunology*; D008239:Lysine / Q000276:immunology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008954:Models, Biological; D013388:Succinimides / Q000276:immunology
D000941:Antigens; D004136:Dinitrobenzenes; D006241:Haptens; D008081:Liposomes; D013388:Succinimides; D008239:Lysine; C001426:N-hydroxysuccinimide