The binding of phosphorylcholine-carrying antigens to the anti-phosphorylcholine monoclonal antibody TEPC 15. A fluorescence spectroscopic study.
The intrinsic fluorescence of the anti-phosphorylcholine monoclonal antibody TEPC 15 has been used to study its interaction with the hapten phosphorylcholine and some phosphorylcholine-carrying lipids. Spectral conditions were selected so as to obtain fluorescence emission attributable mainly to tryptophan residues. Upon addition of the hapten, the fluorescence intensity increases, and the emission maximum is shifted towards lower wavelengths, in a hyperbolic and saturable process. These effects seem to be specific for phosphorylcholine, since they are not produced by the analogue phosphorylethanolamine. The quenching results suggest that a conformational change occurs in the protein upon interaction with the hapten. Upon addition of a variety of phosphorylcholine-carrying lipids, it is shown that the antibody interacts with the hapten when the lipid exists in the form of micelles, but not when it is present in the lamellar phase.
Urbaneja
M A
MA
Department of Biochemistry and Chemistry, Royal Free Hospital School of Medicine (University of London), U.K.
Chapman
D
D
D000818:Animals; D000911:Antibodies, Monoclonal / Q000032:analysis*; D000918:Antibody Specificity; D000941:Antigens / Q000032:analysis*; D001666:Binding Sites, Antibody; D002794:Choline; D005455:Fluorescent Antibody Technique; D006241:Haptens / Q000032:analysis; D008055:Lipids / Q000032:analysis; D010767:Phosphorylcholine / Q000276:immunology*; D011487:Protein Conformation; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000032:analysis
D000911:Antibodies, Monoclonal; D000941:Antigens; D006241:Haptens; D008055:Lipids; D010767:Phosphorylcholine; D014364:Tryptophan; D002794:Choline