组氨酰转移核糖核酸合成酶自身抗原的原核表达及初步临床应用

目的 通过克隆人组氨酰转移核糖核酸合成酶自身抗原Jo-1基因,构建重组表达质粒,获得具有免疫活性的纯化重组蛋白,建立间接ELISA法,并探讨其在检测多发性肌炎/皮肌炎(PM/DM)中的抗Jo-1抗体的价值.方法 构建重组表达载体,在大肠杆菌DH5 α和BL21(DE3)中表达;融合蛋白经Ni-NTA树脂柱进行亲和层析纯化,并通过十二烷基磺酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)和免疫印迹(WB)进行免疫活性鉴定;应用表达蛋白建立间接ELISA法.同时用该方法检测30名正常献血者,30例SLE,30例类风湿关节炎(RA),10例原发性干燥综合征(SS),75例PM/DM患者血清中抗Jo-1抗体.结果 经重组质粒测序和酶切结果证实,Jo-1目的基因已正确插入原核表达载体中,基因序列正确,符合表达框架;经SDS-PAGE检测显示,表达产物在相对分子质量55 000处有一明显的蛋白表达条带;WB分析表明,重组蛋白具有人Jo-1抗原反应性;间接ELISA法检测标本血清结果显示,PM/DM组中抗Jo-1抗体的阳性率为28%,非PM/DM组(疾病对照组及正常对照组)均为阴性,其差异均有统计学意义(x2=31.84,均P＜0.01).结论 成功克隆了人组氨酰转移核糖核酸合成酶自身抗原Jo-1基因,其可在大肠杆菌中表达,且重组自身抗原具有较好的抗原性和特异性.应用纯化融合蛋白建立的间接ELISA法检测PM/DM抗Jo-1抗体具有较好的特异性.

Cloning and expression of histidyl-tRNA synthetase autoanfigen gene and its clinical application

Objective To clone and construct the recombinant plasmid containing Jo-1 of HepG2 cells,then purify the protein and identify the immunoreactivity of the recombinant protein.and establish the enzyme linked immunosorbent assay(ELSA)to detect Jo-1 autoantigen correlative antibodies in diagnosis of polymyositis/dermatomyositis.Methods The constructed plasmid was transformed into E.coli.DH5α and BL21(DE3).This fusion protein was purified by Ni-NTA chromatography and its immunnoreactivity was identified by SDS-PAGE and Western blot.ELISA with the fusion protein was established to detect the Jo-1 autoantigen correlative antibodies in sernm samples of 75 patient with PM/DM,30 patients with SLE.30 patients with RA,10 patients with SS and 30 normal controls.Results The sequence of Jo-1 autoantigen gene Was the same as the sequence reported on the literatures.SDS-PAGE gel analysis showed the molecular weisat of fusion protein was approximately 55 000 Da. Western blotting analysis showed that the fusion protein had the same immunoreactivity as human Jo-1 autoantigen.The results of ELISA indicated that the positive rate of anti-Jo-1 antibody was 28%.but the antibody was negative in other controls.There was significant difierence of positivity of the autoantibody between PM/DM and disease controls or normal controls (x2=31.84,P＜0.01).Conclusions The plasmid containing Jo-1 is successfully cloned into E.coli.DH5α and BL21 (DE3).EUSA analysis shows its good antigenicity and specificity.