Frank H G, Huppertz B, Kertschanska S, Blanchard D, Roelcke D, Kaufmann P
Institut für Anatomie der RWTH Aachen, Germany.
Histochem Cell Biol. 1995 Oct;104(4):317-29. doi: 10.1007/BF01464328.
Recently, fibrinoid of the human placenta has been described as being composed of two main types differing in origin and chemical composition. Fibrin-type fibrinoid is mostly a blood clot product. Matrix-type fibrinoid was defined as the extracellular matrix secreted by extravillous trophoblast cells. The structure and composition of matrix-type fibrinoid was addressed in this study, focusing on fibronectins as one major constituent. A panel of antibodies directed against different fibronectin isoforms generated by different mRNA splicing, as well as antibodies recognizing oncofetal carbohydrate epitopes, were used on cryostat, paraffin and Lowicryl sections of placental tissue from different stages of pregnancy. The oncofetal carbohydrate epitopes studied comprised the blood group precursor antigens i and I. We identified the blood group-related antigen i as an additional marker for matrix-type fibrinoid. The antigen was detected on a glycoprotein that was also recognized by the fibronectin antibodies in western blots. Immunohistochemically this i-glycosylated oncofetal fibronectin-like molecule of about 55 kDa is expressed only by the invasive phenotype of extravillous trophoblast. Long chain carbohydrate moieties with a structure fulfilling the criteria for i reactivity on human placental fibronectin are known to have antiadhesive properties and to enhance resistance of the protein chain to proteolysis. These properties underline the functional relevance of glycosylation of fibronectins in matrix-type fibrinoid and suggest matrix-type fibrinoid is a typical matrix of invasive cells. In contrast, the more mature blood group precursor I could be detected after sialidase pretreatment of sections. This antigen was expressed by villous, non-invasive trophoblast.
最近，有人描述人类胎盘的纤维蛋白样物质由两种起源和化学成分不同的主要类型组成。纤维蛋白型纤维蛋白样物质主要是血凝块产物。基质型纤维蛋白样物质被定义为绒毛外滋养层细胞分泌的细胞外基质。本研究探讨了基质型纤维蛋白样物质的结构和组成，重点关注纤连蛋白这一主要成分。一组针对不同mRNA剪接产生的不同纤连蛋白异构体的抗体，以及识别癌胚碳水化合物表位的抗体，被用于妊娠不同阶段胎盘组织的冰冻切片、石蜡切片和Lowicryl切片。所研究的癌胚碳水化合物表位包括血型前体抗原i和I。我们将血型相关抗原i鉴定为基质型纤维蛋白样物质的另一个标志物。在蛋白质印迹中，该抗原在一种糖蛋白上被检测到，该糖蛋白也被纤连蛋白抗体识别。免疫组织化学显示，这种约55 kDa的i糖基化癌胚纤连蛋白样分子仅由绒毛外滋养层的侵袭性表型表达。已知人胎盘纤连蛋白上具有符合i反应性标准结构的长链碳水化合物部分具有抗黏附特性，并能增强蛋白质链对蛋白水解的抗性。这些特性强调了纤连蛋白糖基化在基质型纤维蛋白样物质中的功能相关性，并表明基质型纤维蛋白样物质是侵袭性细胞的典型基质。相比之下，在切片经唾液酸酶预处理后可检测到更成熟的血型前体I。该抗原由绒毛的非侵袭性滋养层表达。
