Human IgG monoclonal autoantibodies against muscle acetylcholine receptor: direct evidence for clonal heterogeneity of the antiself humoral response in myasthenia gravis.
Human hybridomas were established from myasthenia gravis (MG) patients and screened using a fast and sensitive cell ELISA with the rhabdomyosarcoma cell line TE671. In a first series of 14 fusions using a standard protocol, 36 positive clones were detected and maintained for three passages. The number of clones in each fusion was correlated with in vivo titers of anti-acetylcholine receptor (AChR) autoantibodies. In a second series of four experiments, fusions were immediately followed by cell plating under limiting dilution conditions ('fusion cloning') providing eight stable hybridomas. These hybridomas produced monoclonal antibodies (mAbs) of IgG isotype reactive with TE671 cells, but not with AChR in solution using the radioimmunoprecipitation assay. Fine analysis of antigen specificity of these mAbs was performed using solid-phase ELISA against purified AChR from Torpedo (T-AChR) and immunoblot against recombinant chimaeric human AChR produced in bacteria. Five of the eight mAbs derived from the few patients whose antibodies showed cross-reactivity with T-AChR reacted against T-AChR. Of these five mAbs, two also reacted against chimaeric human AChR by immunoblotting. Furthermore, at least one of these two mAbs was capable of inducing antigenic modulation of labeled AChR with [125I]alpha-bungarotoxin from the surface of TE671 cells. These mAbs provide useful tools to explore the molecular basis of the structural and functional heterogeneity of the humoral anti-AChR response in myasthenia gravis.
Cardona
A
A
INSERM U 25, Hôpital Necker, Paris, France.
Garchon
H J
HJ
Vernet-der-Garabedian
B
B
Morel
E
E
Gajdos
P
P
Bach
J F
JF
D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology*; D000917:Antibody Formation; D000918:Antibody Specificity; D001323:Autoantibodies / Q000276:immunology*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000276:immunology*; D008297:Male; D009132:Muscles / Q000276:immunology*; D009157:Myasthenia Gravis / Q000276:immunology*; D011950:Receptors, Cholinergic / Q000276:immunology*
D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D007074:Immunoglobulin G; D011950:Receptors, Cholinergic