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[关键词] 妊娠相关血浆蛋白A;固相时间分辨荧光免疫;亲和素—生物素—聚乙烯胺—4,7二氯磺苯基1,10啡罗啉2,9二羧酸—铕复合物;唐氏综合征
Develop A Direct Solid Phase Lanthane Time瞨esolved Fluoroimmunoassay Reagent of PAPP睞utilizing PVA
Abstract :Objective To develop a direct solid phase lanthane time瞨esolved fluoroimmunoassayreagent of PAPP睞 by synthesizing a complex of (SA)z(Bio)x睵VA(BCPDA)y睧u3 . Methods Polyvinylamine (PVA) was labeled with biotin瞫treptavidin and europium chelate of 4,7瞓is(chlorosulfophenyl)1,10瞤henanthroline2,9瞕icarboxylic瞐cid(BCPDA). Using labeled PVA complex,We designed two瞫ite sandwich time瞨esolved fluoroimmunoassay of PAPP睞 and evaluated assay characteristics of PAPP睞 kit .Results We successed synthesizing a conjuagete of (SA)z(Bio)x睵VA(BCPDA)y睧u3 and a reagent of PAPP睞. Detection limits achieved were 0.7mIU/L.The calibration curve was linear 010000mIU/L.Intra and interassay imprecision (CV) was 3.89%4.96% and 7.35%9.27%.Recovery was 95.8%104.2%. Conclusions The conjugate of (SA)z(Bio)x睵VA(BCPDA)y睧u3 synthesizied was reactive ,highly fouorescent. A sorts of kit could be synthesized ,taking advantage of it. The reagent of PAPP睞 was potentially suited for use in clinical with highly analytical sensitivity.
Key words: Pregnancy associated plasma protein A;Direct solid phase lanthane time瞨esolved fluoroimmunoassay; Streptavidin瞓iotin睵olyvinylamine europium chelate of 4,7瞓is(chlorosulfophenyl)1,10瞤henanthroline2,9瞕icarboxylic瞐cid; Down's Syndrome
妊娠相关血浆蛋白A(Pregnancy associated plasma protein A,PAPP睞)是一种高分子α2糖蛋白,20世纪70年代在孕妇血清中被发现[1]。在孕妇血中主要PAPP睞是胎盘滋养层组织分泌,它是一种异源四聚体,由两个分子量为200 000~250 000亚基构成。PAPP睞亚基和两个嗜红细胞主要基础蛋白(Proform of eosinophil major basic protein)以二硫键结合而成[2],在孕妇血中只存在微量游离单体PAPP睞。PAPP睞亚基由1 547个多聚核苷酸构成,包括1个拉长的锌指结构,3个Lin—notch重复序列,以及5个短一致重复序列[3]。在体内PAPP睞是一种蛋白酶,主要针对胰岛素样生长因子结合蛋白4(IGFBP4)和胰岛素样生长因子结合蛋白5(IGFBP5)起作用。胰岛素样生长因子I(IGF睮)在促进细胞分裂和增殖起重要作用,它主要通过IGF1受体起作用,IGF睮、II的生物活性受6个高亲和性IDFBP调节[4,5]。PAPP睞主要用于产前筛查唐氏综合征(Down's Syndrome,DS),迄今医学上对此病尚无有效的治疗和预防措施,只能通过产前筛查防止DS儿的出生,但目前开展的绒毛活检,羊水穿刺及脐带血穿刺均为侵入性检查,有1%~3%的流产率,且方法繁琐,出报告时间长,不适宜大范围孕妇的普查,仅限于高危人群的诊断。大量报道认为PAPP睞可作为DS胎儿产前筛查的的标志物。在15周~20周通过结合孕妇孕周、超声诊断和Freeβ睭CG可以鉴别65%~75%,但要在3个月~6个月结合AFP、游离E3以及抑制素上述成分可鉴别85%~90%[6]。有文献[7]报道PAPP睞在急性冠状动脉综合征(ACS)的早期诊断有一定的意义,PAPP睞在ACS患者血清含量<30 mIU/L,同时结构不同于孕妇体内的PAPP睞且存在动态变化,必须利用超灵敏的方法进行检测。国内PAPP睞的诊断试剂大多为ELISA和PerkinElmer公司生产的解离增强时间分辨荧光免疫分析(dissociated enhance lanthane time瞨esolved fluoroimmunoassay,DELFIA)试剂,无国产PAPP睞时间分辨荧光试剂。我们利用PVA(聚乙烯胺)作为载体结合BCPDA镧系螯合物合成一种高灵敏的固相时间分辨荧光免疫分析(direct solid phase lanthane time resolved fluoroimmunoassay,DSLFIA)试剂。为提高检测灵敏度和克服BCPDA标记抗体使抗体失活的问题,我们引入了生物素睬缀退(biotin瞫treptavidin system)系统。