Giuliani M M, Conti R, Ceccarini C, Terrana B, Tecce M F
J Nucl Med Allied Sci. 1989 Jul-Sep;33(3 Suppl):94-7.
Determination of serum alpha-fetoprotein is useful in the clinical management of liver cancer, but it has not been particularly helpful in the early diagnosis of this disease, since also non-neoplastic liver diseases may result in small increases of its serum concentration. To improve the clinical performance of this assay, we have previously developed an in vitro culture system, in which the expression of alpha-fetoprotein and albumin could be coordinately modulated by thyroid hormone. This system allowed large scale production and purification of native alpha-fetoprotein to be used as reference material. In addition, we synthesized and cloned in a bacterial expression vector a DNA sequence coding of human alpha-fetoprotein amino acid sequence 38-119. This alpha-fetoprotein sequence was chosen since it is the least homologous to albumin, being the amino acid sequence of the two proteins extremely similar with an overall identity of about 38%. Now we have obtained three hybridomas recognizing with high affinity and specificity both the recombinant fragment and native alpha-fetoprotein. These antibodies, which therefore recognize the native protein in the amino acid sequence 38-119, should allow the development of an immunoassay for alpha-fetoprotein with absolute selectivity versus albumin. This might result in more sensitive clinical determinations, avoiding the possibility of cross-reactions.
血清甲胎蛋白的测定对肝癌的临床管理有用，但在该疾病的早期诊断中并非特别有帮助，因为非肿瘤性肝病也可能导致其血清浓度小幅升高。为提高该检测方法的临床性能，我们先前开发了一种体外培养系统，在该系统中，甲胎蛋白和白蛋白的表达可受甲状腺激素协同调节。该系统可大规模生产和纯化天然甲胎蛋白用作参考物质。此外，我们在细菌表达载体中合成并克隆了一段编码人甲胎蛋白氨基酸序列38 - 119的DNA序列。选择该甲胎蛋白序列是因为它与白蛋白的同源性最低，这两种蛋白质的氨基酸序列极为相似，总体一致性约为38%。现在我们获得了三种杂交瘤，它们对重组片段和天然甲胎蛋白都具有高亲和力和特异性。因此，这些抗体识别氨基酸序列38 - 119中的天然蛋白，应能开发出一种对甲胎蛋白具有相对于白蛋白的绝对选择性的免疫测定法。这可能会带来更灵敏的临床检测结果，避免交叉反应的可能性。
