Shaha C, Cheng C Y, Phillips D M, Talwar G P, Bardin C W
National Institute of Immunology, New Delhi, India.
Int J Androl. 1988 Dec;11(6):547-59. doi: 10.1111/j.1365-2605.1988.tb01027.x.
Testibumin is a glycoprotein previously isolated from the spent media of primary Sertoli cell-enriched cultures prepared from 20-day-old rats. Immunoassayable testibumin is found in the highest concentrations in testis, epididymis and fluids of the male reproductive tract in adult rats. In the present study, light microscopy was used to show that immunostainable testibumin in paraffin sections of rat testis was localized along the base of the seminiferous epithelium and in finger-like projections from the base of the epithelium, corresponding to the position of the Sertoli cells. The immunostaining of Sertoli cells was shown to be specific since either purified testibumin or crude Sertoli cell-enriched culture medium could compete with antibody for binding sites in tissue sections. The observations using light microscopy were confirmed when Sertoli cells were examined by electron microscopy using a pre-embedding immunostaining technique. The epithelium of the epididymis also contained immunoreactive testibumin which was localized in the caput, corpus and cauda. Immunostainable testibumin was also localized in the corpora lutea of the rat ovary and in the epithelium of the uterine endometrium. These observations are consistent with previous reports that immunoreactive testibumin is present in these organs as demonstrated by radio-immunoassays. We conclude that (i) the immunolocalization of testibumin in Sertoli cells adds to a growing list of observations suggesting that it is made in this cell type; (ii) the other sites of testibumin synthesis in the male are uncertain but the ovary and uterus are possible sites in the female; (iii) electron microscopy following pre-embedding immunostaining and epitope selection can be used as an adjunct to conventional immunocytochemistry to localize proteins in Sertoli cells.
睾丸白蛋白是一种糖蛋白，先前从20日龄大鼠制备的富含支持细胞的原代培养物的用过的培养基中分离得到。在成年大鼠的睾丸、附睾和雄性生殖道的液体中，可免疫检测到的睾丸白蛋白浓度最高。在本研究中，使用光学显微镜显示，大鼠睾丸石蜡切片中可免疫染色的睾丸白蛋白定位于生精上皮的基部以及上皮基部的指状突起中，对应于支持细胞的位置。支持细胞的免疫染色显示是特异性的，因为纯化的睾丸白蛋白或粗制的富含支持细胞的培养基都可以与抗体竞争组织切片中的结合位点。当使用预包埋免疫染色技术通过电子显微镜检查支持细胞时，光学显微镜的观察结果得到了证实。附睾上皮也含有免疫反应性睾丸白蛋白，其定位于附睾头、体和尾。可免疫染色的睾丸白蛋白也定位于大鼠卵巢的黄体和子宫内膜的上皮中。这些观察结果与先前的报道一致，即通过放射免疫测定法证明这些器官中存在免疫反应性睾丸白蛋白。我们得出以下结论：（i）睾丸白蛋白在支持细胞中的免疫定位增加了越来越多的观察结果，表明它是在这种细胞类型中产生的；（ii）男性中睾丸白蛋白合成的其他部位尚不确定，但卵巢和子宫可能是女性中的合成部位；（iii）预包埋免疫染色和表位选择后的电子显微镜可作为传统免疫细胞化学的辅助手段，用于在支持细胞中定位蛋白质。
