Immunochemical determination of Forssman and blood group A-active glycolipids in human gastric mucosa by inhibition assay of liposome lysis.
A simple liposome immunoassay, liposome immune-lysis inhibition (LILI) assay, is described for quantitative determination of individual glycolipid antigens. Liposomes containing fluorogenic marker, 4-methylumbelliferyl phosphate, were prepared from sphingomyelin, cholesterol, dicetylphosphate and standard glycolipid. Release of trapped markers from these liposomes by antibody and complement (liposome lysis) was inhibited by preincubating the antibody with test glycolipid incorporated into inhibitor liposomes. Based on the competitive inhibition, it was possible to quantitate each glycolipid antigen in less than picomolar amounts. The sensitivity and specificity of the assay were examined with purified glycolipid standards. LILI assay has been applied for the determination of Forssman glycolipid and blood group A-active glycolipid in human gastric mucosa and cancer tissues.
D000017:ABO Blood-Group System; D000906:Antibodies / Q000032:analysis; D000918:Antibody Specificity; D015478:Antigens, Heterophile / Q000032:analysis*; D001667:Binding, Competitive; D000795:Fabry Disease / Q000276:immunology; D005577:Forssman Antigen / Q000032:analysis*; D005753:Gastric Mucosa / Q000276:immunology*; D006017:Glycolipids / Q000276:immunology*; D006801:Humans; D008081:Liposomes / Q000276:immunology*
D000017:ABO Blood-Group System; D000906:Antibodies; D015478:Antigens, Heterophile; D006017:Glycolipids; D008081:Liposomes; D005577:Forssman Antigen