title: Interaction of a monoclonal antibody against hEGF with a receptor site for EGF.
abstract: Epidermal growth factor (EGF) has been detected by radioimmunoassay (RIA) in different body fluids such as serum, amniotic fluid, and urine. Human tumor tissues with EGF receptors (EGF-Rc) may be saturated with EGF, which may be of prognostic value. An RIA was envisaged to measure human epidermal growth factor (hEGF) levels using EGF-Rc as capture agent and a monoclonal antibody anti-hEGF (MAb anti-hEGF) labeled with 125Iodine as a marker for this binding. The purpose of this work was to study the feasibility of MAb anti-hEGF to detect the receptor binding sites and to investigate the interaction between MAb anti-hEGF and the EGF-Rc. Various binding experiments were performed to study possible interference and interactions in the complex MAb anti-hEGF and the receptor. Affinity constants were determined by means of Scatchard plot analysis to interpret the complex stability challenged with other compounds for a better understanding of the interaction process. Binding constants were of the same order for all the ligands tested separately involving the EGF-Rc, but were significantly higher (t = 15.7, p < 0.05) for hEGF in its binding to MAb anti-hEGF. It was possible with equilibrium studies and competition experiments to evaluate the interaction of EGF and MAb anti-hEGF with the EGF receptor. This observation makes the MAb anti-hEGF a potential tracer for the quantitation of receptors in vitro, and possibly for the detection of membrane receptors on tumor cells in vivo.
authors.affiliation: Radiopharmacy Department, Nuclear Research Center, Faculty of Sciences, Montevideo, Uruguay.
authors.forename: S
authors.initials: S
authors.lastname: Valente
authors.forename: B
authors.initials: B
authors.lastname: Souto
authors.forename: H
authors.initials: H
authors.lastname: Balter
authors.forename: M M
authors.initials: MM
authors.lastname: Welling
authors.forename: E
authors.initials: E
authors.lastname: Román
authors.forename: A
authors.initials: A
authors.lastname: Robles
authors.forename: E K
authors.initials: EK
authors.lastname: Pauwels
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry*; D002462:Cell Membrane / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000737:chemistry / Q000276:immunology*; D066246:ErbB Receptors / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D051379:Mice; D011786:Quality Control; D011994:Recombinant Proteins; D013363:Submandibular Gland / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D011994:Recombinant Proteins; D004815:Epidermal Growth Factor; D066246:ErbB Receptors