title: Detection of immune complexes by matrix-assisted laser desorption/ionization mass spectrometry.
abstract: Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was used to detect an immune complex formed between beta-lactoglobulin and polyclonal anti-beta-lactoglobulin antibody in the gas phase. The most important experimental parameters to detect such a specific antibody-antigen complex by MALDI were the use of solutions at near-neutral pH and of sinapinic acid matrix prepared by the dried-droplet method. Under such conditions, predominantly one but also two molecules of antigen protein were complexed by the antibody. Specific formation of the antibody-antigen complex was confirmed by performing competitive reactions. Addition of antibody to a 1:1 mixture of beta-lactoglobulin and one control protein resulted not only in the appearance of the expected antibody-antigen complex, but also in a strong decrease in the free beta-lactoglobulin signal, while the abundance of the control protein was not influenced.
authors.affiliation: Chemical Research Center, Hungarian Academy of Sciences, Budapest, Hungary.
authors.forename: Gitta
authors.initials: G
authors.lastname: Schlosser
authors.forename: Gabriella
authors.initials: G
authors.lastname: Pocsfalvi
authors.forename: Antonio
authors.initials: A
authors.lastname: Malorni
authors.forename: Angel
authors.initials: A
authors.lastname: Puerta
authors.forename: Mercedes
authors.initials: M
authors.lastname: de Frutos
authors.forename: Károly
authors.initials: K
authors.lastname: Vékey
mesh_terms: D000906:Antibodies / Q000032:analysis / Q000737:chemistry / Q000276:immunology; D000936:Antigen-Antibody Complex / Q000032:analysis* / Q000737:chemistry* / Q000276:immunology; D000937:Antigen-Antibody Reactions / Q000276:immunology; D005240:Feasibility Studies; D006863:Hydrogen-Ion Concentration; D007118:Immunoassay / Q000379:methods*; D007074:Immunoglobulin G / Q000032:analysis* / Q000737:chemistry / Q000276:immunology*; D007202:Indicators and Reagents / Q000737:chemistry; D007782:Lactoglobulins / Q000032:analysis* / Q000737:chemistry / Q000276:immunology*; D011485:Protein Binding; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D000906:Antibodies; D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D007202:Indicators and Reagents; D007782:Lactoglobulins