Design, synthesis, and characterization of a 39 amino acid peptide mimic of the main immunogenic region of the Torpedo acetylcholine receptor.
We have designed a 39 amino acid peptide mimic of the conformation-dependent main immunogenic region (MIR) of the Torpedo acetylcholine receptor (TAChR) that joins three discontinuous segments of the Torpedo α-subunit, α(1-12), α(65-79), and α(110 - 115) with two GS linkers: This 39MIR-mimic was expressed in E. coli as a fusion protein with an intein-chitin-binding domain (IChBD) to permit affinity collection on chitin beads. Six MIR-directed monoclonal antibodies (mAbs) bind to this complex and five agonist/antagonist site directed mAbs do not. The complex of MIR-directed mAb-132A with 39MIR has a Kd of (2.11±0.11)×10(-10)M, which is smaller than (7.13±1.20)×10(-10)M for the complex of mAb-132A with α(1-161) and about the same as 3.4×10(-10)M for that of mAb-132A with TAChR. Additionally, the 39MIR-IChBD adsorbs all MIR-directed antibodies (Abs) from an experimental autoimmune myasthenia gravis (EAMG) rat serum. Hence, the 39MIR-mimic has the potential to inactivate or remove pathogenic Torpedo MIR-directed Abs from EAMG sera and to direct a magic bullet to the memory B-cells that produce those pathogenic Abs. The hope is to use this as a guide to produce a mimic of the human MIR on the way to an antigen specific therapeutic agent to treat MG.
University of California, Davis-School of Medicine, Department of Neurology, One Shields Ave., 1515 Newton Ct. Room 510C, Davis, CA 95616, USA; Biochemistry and Molecular Biology Graduate Group and Biochemistry Molecular Cellular and Developmental Biology Graduate Group of UC Davis, Davis, CA 95616, USA.
Vu B
VB
Trinh
University of California, Davis-School of Medicine, Department of Neurology, One Shields Ave., 1515 Newton Ct. Room 510C, Davis, CA 95616, USA; Biochemistry and Molecular Biology Graduate Group and Biochemistry Molecular Cellular and Developmental Biology Graduate Group of UC Davis, Davis, CA 95616, USA.
Alex J
AJ
Foster
University of California, Davis-School of Medicine, Department of Neurology, One Shields Ave., 1515 Newton Ct. Room 510C, Davis, CA 95616, USA; Biochemistry and Molecular Biology Graduate Group and Biochemistry Molecular Cellular and Developmental Biology Graduate Group of UC Davis, Davis, CA 95616, USA. Electronic address: rhfairclough@ucdavis.edu.
Robert H
RH
Fairclough
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000915:Antibody Affinity / Q000276:immunology; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics / Q000276:immunology; D015153:Blotting, Western; D015195:Drug Design; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D007106:Immune Sera / Q000276:immunology; D008958:Models, Molecular; D018716:Molecular Mimicry; D008969:Molecular Sequence Data; D009157:Myasthenia Gravis / Q000097:blood / Q000276:immunology; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D011485:Protein Binding / Q000276:immunology; D017434:Protein Structure, Tertiary; D051381:Rats; D011950:Receptors, Cholinergic / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D014101:Torpedo / Q000235:genetics / Q000276:immunology*
D000911:Antibodies, Monoclonal; D029941:Fish Proteins; D007106:Immune Sera; D010455:Peptides; D011950:Receptors, Cholinergic
Antibody mediated disease; Conformation-dependent epitope; Experimental autoimmune myasthenia gravis (EAMG); Myasthenia gravis (MG)