TY - JOUR
T1 - Characterization of an anti-fetal AChR monoclonal antibody isolated from a myasthenia gravis patient
AU - Saxena, Abhishek
AU - Stevens, Jo
AU - Cetin, Hakan
AU - Koneczny, Inga
AU - Webster, Richard
AU - Lazaridis, Konstantinos
AU - Tzartos, Socrates
AU - Vrolix, Kathleen
AU - Nogales-Gadea, Gisela
AU - Machiels, Barbie
AU - Molenaar, Peter C.
AU - Damoiseaux, Jan
AU - De Baets, Marc H.
AU - Simon-Keller, Katja
AU - Marx, Alexander
AU - Vincent, Angela
AU - Losen, Mario
AU - Martinez-Martinez, Pilar
PY - 2017/10/31
Y1 - 2017/10/31
N2 - We report here the sequence and functional characterization of a recombinantly expressed autoantibody (mAb 131) previously isolated from a myasthenia gravis patient by immortalization of thymic B cells using Epstein-Barr virus and TLR9 activation. The antibody is characterized by a high degree of somatic mutations as well as a 6 amino acid insertion within the VHCDR2. The recombinant mAb 131 is specific for the.-subunit of the fetal AChR to which it bound with sub-nanomolar apparent affinity, and detected the presence of fetal AChR on a number of rhabdomyosarcoma cell lines. Mab 131 blocked one of the two a-bungarotoxin binding sites on the fetal AChR, and partially blocked the binding of an antibody (mAb 637) to the a-subunit of the AChR, suggesting that both antibodies bind at or near one ACh binding site at the a/gamma subunit interface. However, mAb 131 did not reduce fetal AChR ion channel currents in electrophysiological experiments. These results indicate that mAb 131, although generated from an MG patient, is unlikely to be pathogenic and may make it a potentially useful reagent for studies of myasthenia gravis, rhabdomyosarcoma and arthrogryposis multiplex congenita which can be caused by fetal-specific AChR-blocking autoantibodies.
AB - We report here the sequence and functional characterization of a recombinantly expressed autoantibody (mAb 131) previously isolated from a myasthenia gravis patient by immortalization of thymic B cells using Epstein-Barr virus and TLR9 activation. The antibody is characterized by a high degree of somatic mutations as well as a 6 amino acid insertion within the VHCDR2. The recombinant mAb 131 is specific for the.-subunit of the fetal AChR to which it bound with sub-nanomolar apparent affinity, and detected the presence of fetal AChR on a number of rhabdomyosarcoma cell lines. Mab 131 blocked one of the two a-bungarotoxin binding sites on the fetal AChR, and partially blocked the binding of an antibody (mAb 637) to the a-subunit of the AChR, suggesting that both antibodies bind at or near one ACh binding site at the a/gamma subunit interface. However, mAb 131 did not reduce fetal AChR ion channel currents in electrophysiological experiments. These results indicate that mAb 131, although generated from an MG patient, is unlikely to be pathogenic and may make it a potentially useful reagent for studies of myasthenia gravis, rhabdomyosarcoma and arthrogryposis multiplex congenita which can be caused by fetal-specific AChR-blocking autoantibodies.
KW - ARTHROGRYPOSIS MULTIPLEX CONGENITA
KW - NICOTINIC ACETYLCHOLINE-RECEPTOR
KW - CLASSICAL COMPLEMENT ACTIVATION
KW - FAB-ARM EXCHANGE
KW - NEUROMUSCULAR-JUNCTION
KW - SOMATIC HYPERMUTATION
KW - FETAL ANTIGEN
KW - B-CELLS
KW - THYMUS
KW - AUTOANTIBODIES
U2 - 10.1038/s41598-017-14350-8
DO - 10.1038/s41598-017-14350-8
M3 - Article
C2 - 29089519
SN - 2045-2322
VL - 7
JO - Scientific Reports
JF - Scientific Reports
M1 - 14426
ER -