Characterization of Human Anti-acetylcholine Receptor Monoclonal Autoantibodies from the Peripheral Blood of a Myasthenia Gravis Patient Using Combinatorial Libraries

Myasthenia gravis (MG) is an autoimmune disease caused by autoantibodies against the nicotinic acetylcholine receptor (AChR). Using phage-display technology we have characterized the largest panel of anti-AChR monoclonal antibodies thus far isolated from a single patient. Despite having been isolated with either Torpedo AChR or a human peptide, the recombinant antibodies shared with the donorʹs serum the ability to recognize human AChR expressed in its native configuration on the surface of TE671 cells. Their specificity for the main immunogenic region (MIR) of the AChR was demonstrated using a synthetic peptide corresponding to the region 67–76 of the human AChR α subunit and by inhibition of a highly pathogenic rat anti-MIR monoclonal antibody (mAb35). This work demonstrates the value of combinatorial libraries in isolating pathogenic autoantibodies from peripheral blood lymphocytes. Future genetic, structural, and functional analyses of the monoclonal antibodies reported herein should enhance our understanding of the pathogenesis of MG.