Liposome immune lysis assay (LILA): a simple method to measure anti-protein antibody using protein antigen-bearing liposomes.
A new simple immunoassay technique using immune lysis of liposomes was developed to measure antibody against protein antigens. Multilamellar liposomes were composed of dipalmitoylphosphatidylcholine, cholesterol and phosphatidylethanolamine substituted with the hetero-bifunctional cross-linking reagent N-hydroxysuccinimidyl 3-(2-pyridyldithio)propionate (SPDP). The protein antigen (human IgG) was coupled to these liposomes after treatment with SPDP and mild reduction. As a release marker, carboxyfluorescein (CF) was entrapped in the liposomes. The CF release was specific to anti-human IgG antibody and depended on the presence of complement. This technique could detect 10(-15) mol of anti-human IgG antibody or human IgG. The liposomes were stable over 8 months at 4 degrees C under nitrogen gas.
D000818:Animals; D000906:Antibodies / Q000032:analysis*; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D002784:Cholesterol; D003165:Complement System Proteins / Q000276:immunology; D006168:Guinea Pigs; D006801:Humans; D007118:Immunoassay; D007074:Immunoglobulin G / Q000032:analysis*; D007202:Indicators and Reagents; D007700:Kinetics; D008081:Liposomes; D010714:Phosphatidylethanolamines; D011663:Pulmonary Surfactants
D000906:Antibodies; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D007202:Indicators and Reagents; D008081:Liposomes; D010714:Phosphatidylethanolamines; D011663:Pulmonary Surfactants; D003165:Complement System Proteins; D002784:Cholesterol