抗乙酰胆碱受体α－银环蛇毒素结合区抗体可变区的序列分析

SEQUENCE ANALYSIS OF ANTIBODIES AGAINST α-BUNGAROTOXIN BINDING SITES ON ACETYLCHOLINE RECEPTOR

通过对３株抗乙酰胆碱受体（ＡＣｈＲ）的α－银环蛇毒素（α－ＢＴ）结合区抗体的配位特异性测定和可变区基因序列分析，探讨重症肌无力（ＭＧ）的发病机制。这３株抗体相互竞争对ＡＣｈＲ的结合，说明它们具有共同的识别部位。３株抗体的Ｈ链可能来源于同─种系基因，并且在抗原亲和成熟过程中发生体细胞突变；Ｌ链则由不同的亚组基因编码。结果表明，抗ＡＣｈＲα－ＢＴ结合区抗体的Ｈ链在决定抗体配位特异性上起重要作用。

The sequence analysis and paratope mapping of three antibodies against α-bungarotoxin (α-BT)binding sites on acetylcholine receptor(AChR) were studied. The antibodies compete against each other to the α-BT binding sites on AChR indicated that they recognized the same or overlapping epitopes,The high homology(98.8%～99 .4%)among the heavy chains of the antibodies revealed that the heavy chains of the antibodies are probably evolved from a common precursor by antigen-affinity maturation, However,the different light chains used in the antibodies suggest that the heavy chain plays an important role in the specificity of the antibodies.