title: Quantitation of serum IgE by using chimeras of human IgE receptor and avian immunoglobulin domains.
abstract: Anti-IgE therapeutics represent an efficient approach in the management of IgE-mediated allergic asthma. However, monitoring the reduction of IgE levels into a therapeutically efficient range requires the determination of residual serum IgE. We established an analytical approach to distinguish free and anti-IgE complexed serum IgE based on soluble derivatives of the human high-affinity IgE receptor. Soluble receptor derivatives represent an ideal means to analyze receptor antagonism by any ligand or blocking antibody. Therefore, the FcεRI ectodomain was fused with avian IgY constant domains that circumvent susceptibility to interference phenomena and improve assay performance. After production in HEK293 cells, subsequent characterization by enzyme-linked immunosorbent assay and immunoblotting confirmed the suitability of avian IgY constant domains for immobilization and detection purposes. To provide further insights into the different IgE reactivities, free allergen-specific IgE was also determined. Monitoring of sera from omalizumab-treated patients during the course of therapy revealed the applicability for assessment of omalizumab-complexed versus noncomplexed serum IgE. These parameters may allow correlation to clinical responses during anti-IgE therapy with the perspective of biomonitoring.
authors.affiliation: PLS Design, 20255 Hamburg, Germany.
authors.forename: Ingke
authors.initials: I
authors.lastname: Braren
authors.forename: Kerstin
authors.initials: K
authors.lastname: Greunke
authors.forename: Charles
authors.initials: C
authors.lastname: Pilette
authors.forename: Martin
authors.initials: M
authors.lastname: Mempel
authors.forename: Thomas
authors.initials: T
authors.lastname: Grunwald
authors.forename: Reinhard
authors.initials: R
authors.lastname: Bredehorst
authors.forename: Johannes
authors.initials: J
authors.lastname: Ring
authors.forename: Edzard
authors.initials: E
authors.lastname: Spillner
authors.forename: Markus
authors.initials: M
authors.lastname: Ollert
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D061067:Antibodies, Monoclonal, Humanized; D000918:Antibody Specificity / Q000187:drug effects; D001667:Binding, Competitive / Q000187:drug effects; D002645:Chickens; D004797:Enzyme-Linked Immunosorbent Assay; D057809:HEK293 Cells; D006801:Humans; D055767:Immobilized Proteins / Q000378:metabolism; D007118:Immunoassay; D007073:Immunoglobulin E / Q000097:blood*; D007136:Immunoglobulins / Q000737:chemistry* / Q000276:immunology; D000069444:Omalizumab; D017434:Protein Structure, Tertiary; D017455:Receptors, IgE / Q000737:chemistry* / Q000276:immunology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; C016512:IgY; D055767:Immobilized Proteins; D007136:Immunoglobulins; D017455:Receptors, IgE; D011994:Recombinant Proteins; D000069444:Omalizumab; D007073:Immunoglobulin E