L-天冬酰胺酶表面呈现对P277肽免疫原性及抗NOD小鼠糖尿病作用的影响

将P277多肽融合在 Ｌ-天冬酰胺酶的C端，中间引入破伤毒素肽(TTP)，重组嵌合酶AnsB-TTP-P277能以可溶性蛋白的形式表达于大肠杆菌周质内，且能保持大约80%的天然酶催化活力.用纯化的嵌合酶腹腔注射非肥胖性(NOD)小鼠, 可成功诱导小鼠体内产生高水平抗P277抗体.研究表明,P277肽可呈现于 Ｌ-天冬酰胺酶表面，有效地克服单独P277的弱免疫原性，激发机体产生较强烈的免疫反应.小鼠胰腺病理学切片也显示：重组嵌合酶AnsB-TTP-P277和单纯P277肽相比，能更有效地抑制NOD小鼠糖尿病的发生.

L -asparaginase display of P277 for autoimmune diabetes prevention

The recombinant chimeric enzyme of AnsB-TTP-P277 comprising L-asparaginase,a tetanus toxin peptide spacer and P277 was expressed as a soluble protein in Escherichia coli.The purified chimeric enzyme exhibited primary activity of the native asparaginase.Prediabetic NOD mice immunized with the chimeric enzyme could induce specific antibodies against P277 and the specificity of anti-P277 antibodies was verified by Western blot assay.The study showed that displaying the P277 epitope on the surface of asparaginase could effectively overcome the weak antigenicity of the P277 epitope and evoke a strong P277-specific immune response in mice.Moreover,the concentration of blood glucose was measured by an automated analyzer.Histochemical analysis of mice pancreas tissues showed that the administration of the chimeric enzyme to NOD mice could prevent the development of diabetes more efficiently than the peptide P277 itself.