Ohnishi R, Fukuoka T, Furuta T, Moriya Y, Nishimoto A, Tabuchi K
No To Shinkei. 1985 Dec;37(12):1145-54.
The authors investigated the immunohistochemical localization of S-100 protein in normal human brain and glioblastoma tissues by the peroxidase anti-peroxidase method of Sternberger. In normal human brain the positive immunoperoxidase reaction for S-100 protein was observed in astrocytes, oligodendrocytes, ependymal cells, Bergmann's glial cells and epithelial cells of choroid plexus. No positive staining was revealed in any cortical neurons. Immunoelectron-microscopically, the electron dense positive reaction for S-100 protein was seen throughout the cytoplasm, nucleoplasm and cell processes of astrocyte as well as oligodendrocyte. The positive reaction for S-100 protein was demonstrated occasionally in association with cytoplasmic membrane or the membrane constituting cell organelles. We suspect that this observation indicates the existence of membrane-bound form of S-100 protein. In glioblastoma cells, the positive reaction for S-100 protein was relatively weak in intensity as compared with astrocytes, and the degree of positive staining varied from cell to cell. Subcellular localization of S-100 protein in glioblastoma seemed to be essentially similar to that of normal astrocyte. There are some recent reports concerning immunohistochemical localization of alpha and beta subunits of S-100 protein. As compared with these reports, the present immunohistochemical results indicate that the rabbit anti-S-100 antibody embloyed in the present study is mainly against beta subunit of S-100 protein. Although there have been many reports concerning immunohistochemical localization of S-100 protein, the biological role of S-100 protein is still speculative. Some hypotheses are advocated in connection with the possible biological role of S-100 protein. For example, the modulation of synaptic transmission by S-100 protein, the participation of S-100 protein in hormonal secretion and in transport of cations through lipid membrane, the activation of protein kinase and the promotion of disassembly of microtubules by S-100 protein are postulated. It is hard to assume the biological role of S-100 protein based on the immunohistochemical results alone. The present study clearly indicates that S-100 protein exists widely in the cytoplasm, nucleoplasm, cytoplasmic membrane, outer membranes of cell organelles and cell processes of glial cells as well as glioblastoma cells. From these results we assume that S-100 protein plays an important role of intracellular transport of cations as one of the calcium binding proteins.
作者采用Sternberger的过氧化物酶抗过氧化物酶法，研究了正常人类大脑和胶质母细胞瘤组织中S-100蛋白的免疫组化定位。在正常人类大脑中，S-100蛋白的免疫过氧化物酶阳性反应见于星形胶质细胞、少突胶质细胞、室管膜细胞、伯格曼胶质细胞和脉络丛上皮细胞。在任何皮质神经元中均未发现阳性染色。免疫电镜下，在星形胶质细胞和少突胶质细胞的整个细胞质、核质和细胞突起中均可见到S-100蛋白的电子致密阳性反应。S-100蛋白的阳性反应偶尔与细胞质膜或构成细胞器的膜相关。我们怀疑这一观察结果表明存在S-100蛋白的膜结合形式。在胶质母细胞瘤细胞中，与星形胶质细胞相比，S-100蛋白的阳性反应强度相对较弱，且阳性染色程度因细胞而异。胶质母细胞瘤中S-100蛋白的亚细胞定位似乎与正常星形胶质细胞基本相似。最近有一些关于S-100蛋白α和β亚基免疫组化定位的报道。与这些报道相比，本研究的免疫组化结果表明，本研究中使用的兔抗S-100抗体主要针对S-100蛋白的β亚基。尽管已有许多关于S-100蛋白免疫组化定位的报道，但S-100蛋白的生物学作用仍属推测。关于S-100蛋白可能的生物学作用提出了一些假说。例如，推测S-100蛋白对突触传递的调节、S-100蛋白参与激素分泌和阳离子通过脂质膜的转运、S-100蛋白对蛋白激酶的激活以及对微管解聚的促进作用。仅根据免疫组化结果很难推断S-100蛋白的生物学作用。本研究清楚地表明，S-100蛋白广泛存在于胶质细胞和胶质母细胞瘤细胞的细胞质、核质、细胞质膜、细胞器外膜和细胞突起中。从这些结果我们推测，S-100蛋白作为一种钙结合蛋白，在阳离子的细胞内转运中起重要作用。
