Acetylcholine Receptor (AChR) Binding Ab RIA

INTENDED USE

The Calbiotech AChRAb Assay kit is for the determination of anti-acetylcholine receptor

antibody in human serum.



SUMMARY AND EXPLANATION

Myasthenia gravis (MG) is a skeletal muscle disorder characterized by muscular weakness. In such cases, muscular weakness is due to anti-acetylcholine receptor (AChR) antibodies. Anti-AChR antibodies are present in approximately 90% of patients with MG. Anti-AChR antibodies could be: binding antibodies (multitudes of wide populations of antibodies directed to hydrophilic domains of receptors), blocking antibodies (preventing binding of acetylcholine to receptors) and modulating antibodies (accelerating endocytosis resulting in loss of receptors).



PRINCIPLE OF THE TEST

Anti-AChR antibodies are detectable by a radiobinding that is followed by precipitation of the antibodies. Patient specimens and references are incubated with detergent-solubilized fetal and adult AChRs labeled with 125I-alpha-bungarotoxin. The resulting bound complexes of labeled AChRs and autoantibodies are then immunoprecipitated with anti-human IgG. After centrifugation, the supernatant is aspirated and the pellet containing labeled AChR/autoantibody-bound complexes is counted in a gamma counter. Counts are directly proportional to the amount of autoantibodies present.