Santella R M, Gasparro F P, Edelson R L
IARC Sci Publ. 1986(78):127-39.
Methods are now available for the quantification of carcinogen-DNA adducts in human tissues and can be used to screen populations for exposure to environmental carcinogens. One approach utilizes highly specific antibodies in sensitive immunoassays for quantifying adduct levels in DNA from various tissues. We have recently developed a panel of monoclonal antibodies that specifically recognize DNA modified by methoxsalen and ultraviolet A light (320-400 nm) (UVA). These antibodies have been characterized as to sensitivity and specificity by an enzyme-linked immunosorbent assay (ELISA). In a competitive ELISA, 50% inhibition of antibody binding occurred with 17 fmol methoxsalen-DNA photo adducts. There was also some antibody cross-reactivity with DNA modified by 4'-aminomethyl-4,5,8-trimethylpsoralen and 4',5-dimethylangelicin but not with free methoxsalen. A more sensitive ELISA has also been developed using fluorescence detection of enzyme activity. With this assay, one adduct per 10(8) bases can now be detected reliably. Adduct levels have been quantified in myeloma cells and lymphocytes treated in vitro with methoxsalen and UVA. In addition, in preliminary studies, adducts have been measured in lymphocytes isolated from patients undergoing extracorporeal photophoresis for cutaneous T-cell lymphoma. Quantification of methoxsalen adducts in patients should provide a basis for estimating risk resulting from psoralen plus UVA (PUVA) treatment.
目前已有方法可对人体组织中的致癌物 - DNA加合物进行定量，并且可用于筛查人群是否接触环境致癌物。一种方法是在灵敏的免疫测定中利用高度特异性抗体来定量各种组织DNA中的加合物水平。我们最近开发了一组单克隆抗体，它们能特异性识别由甲氧沙林和紫外线A光（320 - 400纳米）（UVA）修饰的DNA。这些抗体已通过酶联免疫吸附测定（ELISA）对其敏感性和特异性进行了表征。在竞争性ELISA中，17飞摩尔的甲氧沙林 - DNA光加合物可导致50%的抗体结合抑制。该抗体与由4'-氨甲基 - 4,5,8 - 三甲基补骨脂素和4',5 - 二甲基白芷素修饰的DNA也有一些交叉反应，但与游离的甲氧沙林没有交叉反应。还开发了一种更灵敏的ELISA，利用酶活性的荧光检测。通过这种测定法，现在可以可靠地检测到每10⁸个碱基中有一个加合物。已对体外经甲氧沙林和UVA处理的骨髓瘤细胞和淋巴细胞中的加合物水平进行了定量。此外，在初步研究中，已对从接受体外光化学疗法治疗皮肤T细胞淋巴瘤的患者中分离出的淋巴细胞中的加合物进行了测量。对患者甲氧沙林加合物的定量应可为评估补骨脂素加UVA（PUVA）治疗所产生的风险提供依据。
