Muscle acetylcholine receptor (AChR) binding (IgG and IgM) are measured quantitatively by immunoprecipitation assays. The high-affinity ligand (125)I-alpha-bungarotoxin is complexed with detergent-solubilized muscle AChR prepared from a mixture of innervated and denervated human muscle. AChR modulating antibodies is detected in a bioassay; (125)I-bungarotoxin measures percent loss of AChR from viable, noninnervated, monolayer cultures of human muscle cells following 14-hour incubation with patient's serum.(Griesmann GE, Kryzer TJ, Lennon VA: Autoantibody profiles of myasthenia gravis and Lambert-Eaton myasthenic syndrome. In Manual of Clinical and Laboratory Immunology. Sixth edition. Edited by NR Rose, RG Hamilton, B Detrick. Washington, DC, ASM Press, 2002, pp 1005-1012)
ACh receptor (muscle) binding antibody: Monday through Friday, Sunday; 2 p.m.
ACh receptor (muscle) modulating antibodies: Monday through Thursday, Saturday; 12 p.m.