Author(s): Ueno S, Wada K, Takahashi M, Tarui S
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Abstract This study was performed to examine the presence and immunological properties of acetylcholine receptor (AChR) in rabbit thymus. Binding of 125I-alpha Bungarotoxin (alpha BGT) to Triton extract from rabbit thymus was saturable (half saturation value: 10 X 10(-9) M) and occurred with at least two affinities, a high one with a dissociation constant of 1.1 X 10(-10)M and a low affinity one with a dissociation constant of 2 X 10(-9)M. The complex formation of 125I-alpha BGT-thymus extract was inhibited by both carbamylcholine and D-tubocurarine. These results indicate the existence of AChR in rabbit thymus. Antibody to AChR which was purified from experimental myasthenic rabbits with Narke AChR-affinity gel and labelled with 125I was used to identify the receptor antigenicity in rabbit thymus. Specific binding of 125I-antibody to thymic extract was demonstrated by the DEAE-paper disc assay. It is concluded from these results that AChRs with a similar antigenicity to that of skeletal muscle AChR exist in rabbit thymus. Our findings obtained in this study will support a hypothesis that the primary immunogen in myasthenia gravis may be AChR in thymus and an autoimmune reaction against AChR might be initiated within the thymus gland itself.
This article was published in Clin Exp Immunol
and referenced in Journal of Addiction Research & Therapy