title: Immunogenicity of immunoliposomes: reactivity against species-specific IgG and liposomal phospholipids.
abstract: Immunoliposomes with surface-linked avidin-biotinylated mouse IgG2a were prepared from dipalmitoylphosphatidylcholine (DPPC), dimyristoylphosphatidylglycerol (DMPG) and biotinylated dipalmitoylphosphatidylethanolamine (DPPE-biotin) in the molar ratio 10:1:0.1 with or without 5 mol% poly(ethylene glycol) dipalmitate (PEG-(C18)2). The ability of IgG2a immunoliposomes to elicit anti-IgG2a antibodies in mice was compared with alum and N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP). IgG2a 5 microgram/mouse) did not elicit an IgG1 antibody response after 4 s.c. injections. Alum-adsorbed IgG2a elicited 2.1 +/- microgram IgG1 antibody/ml serum, whereas MDP elicited 24.3 +/- microgram/ml serum. IgG2a immunoliposomes elicited 12.4 +/- 3.7 microgram IgG1 antibody/ml serum, while immunoliposomes containing lipophilic PEG-(C18)2 elicited 21.4 +/- 5.1 microgram IgG1 antibody/ml serum. Elicited antibodies were specific for IgG2a, with no cross-reactivity with IgG2b. Anti-DPPC or anti-DMPG IgG antibody levels did not change during immunization. Anti-DPPE IgG antibody levels were slightly but significantly elevated during immunization, and there was a significant increase in the level of anti-DPPE-biotin antibodies. These results demonstrate that immunoliposomes prepared with species-specific antibody are immunogenic and induce significant levels of isotypespecific antibody upon repeated injection.
authors.affiliation: Faculté de Pharmacie, Université de Montréal, Québec, Canada.
authors.forename: N C
authors.initials: NC
authors.lastname: Phillips
authors.forename: J
authors.initials: J
authors.lastname: Dahman
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology*; D000918:Antibody Specificity; D001666:Binding Sites, Antibody; D001710:Biotin / Q000276:immunology; D005260:Female; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000276:immunology*; D008081:Liposomes / Q000276:immunology* / Q000494:pharmacology; D051379:Mice; D010714:Phosphatidylethanolamines / Q000276:immunology; D010715:Phosphatidylglycerols / Q000276:immunology; D010743:Phospholipids / Q000276:immunology* / Q000494:pharmacology; D013045:Species Specificity
chemical_list: D000276:Adjuvants, Immunologic; D000888:Antibodies, Anti-Idiotypic; D007074:Immunoglobulin G; D008081:Liposomes; D010714:Phosphatidylethanolamines; D010715:Phosphatidylglycerols; D010743:Phospholipids; C007510:1,2-dipalmitoyl-3-phosphatidylethanolamine; D001710:Biotin; C002773:dimyristoylphosphatidylglycerol