肿瘤标志物放射免疫分析进展

本文从免疫分析总体发展的过程中展示了肿瘤标志物分析的进展.从经典的竞争性RIA到以IRMA开始的非竞争性免疫分析和多分析物微点阵的出现,其中非竞争分析的成功是一个历史性转折.肿瘤标志物的诞生恰遇这一变革,大都直接采用了先进的抗体标记、双位点、夹心式非竞争性分析技术.根据位点占据的理论,竞争性分析本质上属于间接测定,非竞争性分析属于直接测定;直接量度比间接推导的结果更为精确.因此,直接测量的非竞争性方式是达到分析结果高精确、高灵敏以及其他优越性的最关键因素.在同样条件下非竞争分析的灵敏度可比竞争性分析高一百倍以上.在非竞争分析中非特异性结合很容易达到1%以下,在最佳条件下甚至可以达到0.01%,此时的灵敏度可再上升两个数量级.非竞争分析的优越性同样体现在微点阵分析中.微点阵分析是免疫分析中新的分支,尚在发展之中,肿瘤标志物检测及一般临床常规诊断对它尚无明显需求,它的主要潜力将在大规模筛选实验之中.

Advances of tumor marker radioimmunoassay

This paper showed the advances of tumor marker analysis through the total process of immunoassay developments . During the course of classical competitive RIA (radioimmunoassay) to non-competitive assays beginning with IRMA (immunoradiometric assay), and further to multi-analyte micro-array, the success of non-competitive assay was a historical turning point. The birth of tumor markers was just a coincidence with this change. Therefore, most of the tumor marker detections directly applied antibody-labeled, sandwich type, non-competitive assay techniques. According to the theory of site-occupying, competitive assay actually belonged to indirect measuring; but the non-competitive assay was a kind of direct measuring. As a common knowledge, the direct measuring must be more accurate than indirect deduction. Therefore, non-competitive manner with direct measuring was the most key factor for achieving high accuracy, high sensitivity, and better performance. With the same conditions, the sensitivity of non-competitive assay could 100-fold higher than competitive assay. In the non-competitive assay, it was easy to achieve a non-specific binding of less than 1%; and with optimum, the non-specific binding of 0.01% could be achieved. In later case, the sensitivity would be raised further 2 orders of magnitude. The advantage of non-competitive assay was also reflected in the micro-array assay. Micro-array assay is a new branch in the immunoassay field, still being in developing. It seems no demand for micro-array assay yet in the tumor marker detections and in most clinical routine diagnoses now. But it would have potential superiority in the large scale screening test.