A monoclonal antibody directed against an autoimmune epitope on the human beta1-adrenergic receptor recognized in idiopathic dilated cardiomyopathy.
A monoclonal antibody (MAb M16) was obtained by immunizing Balb/C mice with free peptide H26R, corresponding to the second extracellular loop of the human beta1-adrenergic receptor (beta1AR), against which functional autoantibodies have been detected in patients with idiopathic dilated cardiomyopathy. The MAb was found to be of IgG2b type and directed against a conformational epitope, encompassing the sequence recognized by the human autoantibodies. BIAcore measurements yielded an equilibrium constant of 6.5 X 10(7) M1 with an association rate constant (kon) of 6.5 X 10(4) M(-1) sec(-1) and a dissociation rate constant (koff) of 1.0 X 10(-3) sec(-1). It immunoprecipitated only poorly the solubilized beta1AR of Sf9 cell membranes. Functionally, the MAb was capable of not only reducing the number of the maximal binding sites to the beta1-adrenergic receptor of transfected Sf9 cell membranes, but also of displaying a positive chronotropic effect on cultured neonatal rat cardiomyocytes. These properties, which the MAb shares with the human autoantibodies, makes it an interesting tool for passive transfer studies in mice.
Mobini
R
R
Wallenberg Laboratory for Cardiovascular Research, Sahlgrenska University Hospital, Gothenburg, Sweden. reza@mobini@wlab.wall.gu.se
Fu
M
M
Wallukat
G
G
Magnusson
Y
Y
Hjalmarson
A
A
Hoebeke
J
J
D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology*; D000915:Antibody Affinity; D001324:Autoantigens / Q000276:immunology*; D002311:Cardiomyopathy, Dilated / Q000276:immunology*; D002478:Cells, Cultured; D018604:Epitope Mapping; D006339:Heart Rate; D006801:Humans; D006825:Hybridomas; D007074:Immunoglobulin G / Q000032:analysis; D051379:Mice; D008807:Mice, Inbred BALB C / Q000276:immunology; D008969:Molecular Sequence Data; D009206:Myocardium / Q000166:cytology; D010455:Peptides / Q000276:immunology; D011233:Precipitin Tests; D051381:Rats; D017208:Rats, Wistar; D018342:Receptors, Adrenergic, beta-1 / Q000235:genetics / Q000276:immunology*; D018411:Spodoptera / Q000235:genetics; D014162:Transfection
D000911:Antibodies, Monoclonal; D001324:Autoantigens; D007074:Immunoglobulin G; D010455:Peptides; D018342:Receptors, Adrenergic, beta-1