β-银环蛇毒素结合蛋白抗体和乙酰胆碱受体抗体亲和性及其在重症肌无力致病中的意义

Affinity Distribution of Antigen-Specific IgG in Rats Immunized with Acetylcholine Receptor and β-bungarotoxin Binding Protein

为了研究β-银环蛇毒素(β-BuTx )结合蛋白在重症肌无力(MG)致病中的作用和意义。我们用牛膈肌乙酰胆碱受体(AChR)和β-BuTx结合蛋白分别免疫Lewis鼠。结果显示AChR免疫鼠能诱导典型的实验性重症肌无力(EAMG)临床症状和血清中高效价的抗AChR抗体。β-BuTx结合蛋白免疫鼠组血清中虽然也能检测到较高效价的β-BuTx结合蛋白抗体,但未观察到明确的EAMG症状。分析和比较了两组免疫鼠血清抗体的亲和指数后发现,β-BuTx结合蛋白抗体亲和指数明显低于AChR抗体亲和指数。我们认为:β-BuTx结合蛋白在实验动物中具有抗原性,但它的抗体亲和性远较AChR为低,这可能是β-BuTx结合蛋白缺乏致Lewis鼠肌无力的重要因素之一。

To explore the role of the β-BuTx binding protein in the pathoegenesis of MG, we immunized Lewis rats with the β-BuTx binding protein or AChR from bovine diaphragm muscle. The AChR-immunized rats developed typical signs of EAMG. while the β-BuTx binding protein immunized rats showed no definite clinical signs of muscular weakness, Although high levels of both IgG antibodies to AChR or β-buTx binding protein were present in the AChR immunized or β-BuTx binding protein immunized rats. After comparing the difference of antibodies to AChR or β-BuTx binding protein between rats immunized with AChR or β-BuTx binding protein, we found that the affinity of antibodies to β-BuTx binding protein was great lower than that of antibodies to AChR. This results demonstrated that the β-BuTx binding protein be of a antigenic protein. The lower affinity of antibodies be associated with lack of clinical feature in EAMG.