Application of highly purified anti-galactocerebroside antibody to the analysis of lipid-lipid or lipid-protein interactions. Significance of lipid matrix.
The significance of the lipid matrix in the reaction of liposomal antigen, antibody and complement (Ag-Ab-C) was analyzed using purified anti-glactocerebroside antibody and synthetic lipids and the following results were obtained. 1. For the optimal Ag-Ab-C reaction it was necesary that galactocerebroside (galxCMH) and lecithin molecules were well dispersed by virtue of cholesterol (Chol) and that the molar ratio of cholesterol to the sum of galactocerebroside and lecithin was more than one. 2. The Ag-Ab-C reactivity changed depending upon the chain length of lecithin, and the maximal reaction was observed in the case of dilauroylphosphatidylcholine. When the fatty acyl chain of lecithin was either shorter or longer than that of dilaurosylphosphatidylcholine, the reactivity was reduced. 3. The Ag-Ab-C reactivity was increased by elongation of the fatty acyl chain of galactocerebroside and an abrupt change was found to be around the carbon number 8 to 10 of the fatty acyl chain. 4. The Ag-Ab-C reactivity was elevated by the increase in unsaturation of fatty acyl moiety. 5. There is a tendency that an increase in the charge of the lipid matrix leads to the reduction of the Ag-Ab-C reactivity. 6. The results suggest that the physicochemical properties of lipids and especially the lipid-lipid interaction in the hydrophobic region of the lipid matrix play an important role in the Ag-Ab-C reaction.
D000906:Antibodies; D000936:Antigen-Antibody Complex; D000941:Antigens; D002554:Cerebrosides / Q000276:immunology*; D002784:Cholesterol; D003168:Complement Fixation Tests; D003165:Complement System Proteins; D000939:Epitopes; D005699:Galactosylceramides / Q000276:immunology*; D008081:Liposomes; D010713:Phosphatidylcholines; D013329:Structure-Activity Relationship
D000906:Antibodies; D000936:Antigen-Antibody Complex; D000941:Antigens; D002554:Cerebrosides; D000939:Epitopes; D005699:Galactosylceramides; D008081:Liposomes; D010713:Phosphatidylcholines; D003165:Complement System Proteins; D002784:Cholesterol