Characterization of monoclonal antibodies directed against squamous cell carcinoma antigens:: Report of the TD-10 workshop
Characterization of monoclonal antibodies directed against squamous cell carcinoma antigens:: Report of the TD-10 workshop
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DOI：
10.1159/000077726
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发表时间：
2004-01-01
期刊：
影响因子：
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通讯作者：
de Bruijn, HWA
中科院分区：
文献类型：
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作者：
Nustad, K;Dowell, BL;de Bruijn, HWA
从参加ISOBM TD-10研讨会的五个国际合作实验室获得了13种针对鳞状细胞癌抗原（SCCA 1和SCCA 2）的单克隆抗体。天然和重组形式的SCCA用于多种方法中以确定这些抗体的反应性和特异性。根据反应性，抗体可分为三组：SCCA 1反应性组（包含仅与重组SCCA 1（rSCCA 1）和天然SCCA 1（nSCCA 1）抗原反应的抗体）、SCCA 2反应性组（包含仅与重组SCCA 2（rSCCA 2）反应的抗体）和泛反应性组（包含与rSCCA 1、nSCCA 1和rSCCA 2反应的抗体）。与放射性碘标记的rSCCA 1的结合表明，所有反应性抗体都具有高亲和力（Kd < 2 x 10（-9）mol/l）。与标记的rSCCA 2的结合表明，5种抗体具有高亲和力（Kd < 2 × 10（-9）mol/l）。使用非还原和还原天然和重组SCCA 1和SCCA 2检测蛋白质印迹上的抗体反应性。一般来说，这些发现表明还原对与SCCA 1的结合几乎没有影响，但通常对与SCCA 2的结合有强烈的影响。抗体与分别与组织蛋白酶L和G复合的rSCCA 1和rSCCA 2的结合用于辅助酶复合SCCA中表位区域的定位。交叉抑制实验表明，SCCA 1反应性抗体代表两个不同的表位组，这是由它们通过组合来自两个表位组的抗体进行SCCA 1特异性测定的能力支持的。SCCA 2反应性基团代表两种相关抗体和一种独特的抗体，如交叉抑制中所见，但它们不形成成功的测定组合。泛反应性抗体的分类更加困难，因为当将rSCCA 1的结果与作为靶标的rSCCA 2进行比较时，一些表位组不同。然而，两种抗体是突出的，SCC 107和SCC 113，因为它们是高亲和力抗体，与SCCA 1和SCCA 2的游离和蛋白酶复合物反应同样良好。使用连续重叠肽和同源性建模进一步研究表位的精确位置。该研讨会的发现强烈表明，重组抗原（rSCCA 1和rSCCA 2）在表位结构上与唾液中的天然对应物以及正常和癌组织的鳞状上皮非常相似。因此，可以合理地得出结论，发现的特异性是可靠的，并且可用于血清中所有形式的鳞状细胞癌的抗体测量，除了SCCA 2与其蛋白酶的复合物。版权所有（C）2004 S. Karger AG，巴塞尔。
Thirteen monoclonal antibodies directed against squamous cell carcinoma antigens (SCCA1 and SCCA2) were obtained from five international collaborating laboratories participating in the ISOBM TD-10 Workshop. Native and recombinant forms of SCCA were used in a wide variety of approaches to determine the reactivity and specificity of these antibodies. Based on reactivity, the antibodies could be divided into three groups: the SCCA1-reactive group containing those that reacted only with recombinant SCCA1 (rSCCA1) and native SCCA1 (nSCCA1) antigens, the SCCA2-reactive group containing those that reacted only with recombinant SCCA2 (rSCCA2), and the pan-reactive group containing those antibodies that reacted with rSCCA1, nSCCA1, and rSCCA2. Binding to radioiodinated rSCCA1 showed that all reactive antibodies were of a high affinity (K-d < 2 x 10(-9) mol/l). Binding to labelled rSCCA2 demonstrated that five antibodies were of a high affinity (K-d < 2 x 10(-9) mol/l). Antibody reactivity on Western blots was tested with nonreduced and reduced native and recombinant SCCA1 and SCCA2. In general, these findings showed that reduction had little effect on binding to SCCA1, but often a strong effect on the binding to SCCA2. Binding of antibodies to rSCCA1 and rSCCA2 in complexes with cathepsin L and G, respectively, was used to assist in the localization of epitope regions in enzyme-complexed SCCA. Cross-inhibition experiments showed that SCCA1-reactive antibodies represent two different epitope groups, and this is supported by their ability to make SCCA1-specific assays by combining antibodies from the two epitope groups. The SCCA2-reactive group represents two related antibodies and one unique as seen in cross-inhibition, but they do not form successful assay combinations. Classification of the pan-reactive antibodies is more difficult, as some epitope groups differ when results from rSCCA1 are compared with rSCCA2 as the target. However, two antibodies are outstanding, SCC107 and SCC113, as they are high-affinity antibodies which react equally well with free and protease complexes of SCCA1 and SCCA2. The precise location of epitopes was further studied using sequential overlapping peptides and homology modelling. The findings from this workshop strongly indicate that the recombinant antigens (rSCCA1 and rSCCA2) are very similar in epitope structure to the native counterparts in saliva, and squamous epithelium from normal and cancer tissues. Therefore, it is reasonable to conclude that the specificities found are reliable and have application for antibody measurement of all forms of squamous cell carcinoma in serum except SCCA2 in complex with its protease. Copyright (C) 2004 S. Karger AG, Basel.