Immunohistochemical study of enzymes using monoclonal antibodies: Oncofetal enzymes.

R-GTP和GST-被称为癌胎儿抗原。由于这些酶的单抗对癌症的诊断和癌变过程的阐明是有用的，我们制备了抗大鼠、兔和人的肾r-GTP和人胎盘GST的单抗，并用免疫组织化学方法检测了这些酶的定位。在成年大鼠肾脏，r-GTP存在于近端小管的刷状缘、近端小管的S_2和S_3段的基侧膜以及亨勒环下降细肢的顶端细胞膜。在人和兔肾中，r-GTP的分布规律与大鼠基本一致。在妊娠18天的大鼠肾脏中，R-GTP存在于近端小管中。随着动物的发育，免疫染色强度逐渐增强。其定位方式与成人基本相同。在大鼠肝脏，新生大鼠(出生后0~1d)和部分肝切除大鼠肝小叶间胆管细胞的蓝小管和顶膜均可见强阳性反应，而成年大鼠仅有极弱的阳性反应。在人的肝脏中，从妊娠7周到成年，沿胆小管可见免疫反应：在产前阶段反应最强。这些结果表明，r-GTP是肝细胞增殖的标志，即肝脏中的癌胚酶。GST-在足月胎盘中定位于胎儿来源的合体滋养细胞和X细胞的无定形细胞质中，为肿瘤组织中GST-酶的研究提供了一种很好的工具。

r-GTP and GST- are known as oncofetal antigens. Since monoclonal antibodies to these enzymes are useful in diagnosis of the cancer and in the elucidation of the cartinogenic process, we have prepared monoclonal antibodies to rat, rabbit and human r-GTP of kindney, and human placenta GST- and examined the localization of these enzymes using immunohistochemistry.In adult rat kidney, r-GTP was present along the brush borders of the proximal tubules, along the basolateral membranes of the S_2 and S_3 segments of the proximal tubules and the apical cell membranes of the descending thin limbs of henle's loop. In human and rabbit kidneies, the distribution patterns of r-GTP almost coincided with those of rat. r-GTP was recognized in proximal tubules at 18-days of gestation in rat kidney. The intensity of the immunostaining increased with the develpoment of animals. The localization pattern was almost the same as that of adult. In rat liver, strong reaction was recognized along the blie canaliculi and apical membrane of interlobular bile ductal cells in neonate(0-1 days of birbh) and in partial hepatectomized rat, however, very faint reaction was present in adult rat. In human liver, immunoreaction was seen along the bile canaliculi from 7-weeks of gestation to adult: the strongest reaction was recognized at the prenatal stages. These results suggested that r-GTP is a marker for proliferating liver cells, i.e. oncofetal enzyme in liver. However, it did not show such change of distribution pattern in kidney and pancreas.GST- was localized in the amorphous cytoplasm of syncytiotrophblasts and X-cells both of which are fetal origin, in full-term human placenta.The monoclonal antibodies in this study may provide a good tool for oncological research of the enzymes in maligant tissues.