人早期胎盘绒毛纤维连接蛋白特异性的研究

我们在对人妊娠5～8周胎盘绒毛和足月胎盘中纤维连接蛋白(FN)进行分离纯化的同时,分析比较了两者的某些生物化学及免疫化学性质。结果:(1)人早期胎盘 FN(epFN)与人足月胎盘FN(tpFN)分子量相似(约500×10~3),是由两个250×10~3 亚基组成,比人血浆FN(pFN)分子量大(约450×10~3)。两者都能与抗人 pFN 抗体反应;(2)epFN、tpFN 及 pFN 都能与抗人羊水 FN 的3个主要功能区单抗发生反应,但 epFN 与抗肝素结合区单抗亲和力大于与抗胶原结合区单抗亲和力,而 tpFN和 pFN 与3种单抗亲和力无明显差异;(3)凝集素结合力实验表明,epFN 与 tpFN 及 pFN 在糖基组成和含量上均有差异;(4)在人早期胎盘绒毛中 FN-结合蛋白的种类和数量都多于足月胎盘。这些结果表明 epFN 可能是人体内一种新的 FN 亚型。

A study on the specific properties of fibronectin from human placenta of early pregnancy

Fibronectins from human placentas of early pregnancy (5～8 weeks) and of term preg-nancy were isolated and purified.Their biochemical and immunological properties were studied.(1) Themolecular weights of early placenta fibronectin (epFN) was similar to that of term placenta fibronectin(tpFN),both were 500×10~3 and were composed of two 250×10~3 subunits,larger than the 450×10~3 ofplasma fibronectin (pFN).They reacted with antisera against pFN.(2) Similar to tpFN and pFN,epFNreacted with mAbs against three main functional domains of amniotic fluid fibronectin (amFN),but theaffinity with the mAb against heparin-binding domain was stronger than that against gelatin-bindingdomain.No obvious differences were observed with tpFN nor with pFN.(3) The results of thelectin-binding capacity indicated that epFN was not only distinct from pFN but also from tpFN in itscarbohydrate composition.(4) There were much more FN-binding proteins in early placenta than interm placenta.These results suggested that epFN might be a new specific fibronectin isoform.