Drug-resistant lymphocytes in man as indicators of somatic cell mutation.
Drug-resistant lymphocytes in man as indicators of somatic cell mutation.
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人体耐药淋巴细胞作为体细胞突变的指标。
DOI：
10.1002/tcm.1770010105
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发表时间：
1980
期刊：
影响因子：
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通讯作者：
Albertini,RJ
中科院分区：
文献类型：
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作者：
Albertini,RJ
人体体细胞突变的直接体内测试可能为评估潜在环境诱变剂的遗传风险提供现实依据。建议将人体内产生的嘌呤类似物（8-氮鸟嘌呤；6-硫鸟嘌呤）抗性（AGr；TGr）外周血淋巴细胞（PBL）的放射自显影测定作为候选测试。带有自然发生的 Lesch-Nyhan (LN) 突变的 PBL 是原型突变细胞。 LN PBL 对 AGrand TGr 敏感，而正常 PBL 对 AG 和 TG 敏感。通过体外抑制植物血凝素 (PHA) 刺激的 3 H-胸苷掺入来判断，可通过多种方法将类似物抗性 LN PBL 与类似物敏感的正常 PBL 区分开来。早期研究通过闪烁光谱法定量 PHA 刺激，在与正常 PBL 的人工混合物中检测到低至 1% 的 LN PBL。虽然 LN 杂合女性可以根据淋巴细胞嵌合体进行识别，但闪烁光谱法太不灵敏，无法检测非 LN 个体中罕见的“LN 样”PBL。然而，放射自显影在正常非 LN 个体中检测到罕见的 TGrPBL。它们的频率并没有随着年龄的增长而增加。通过这种方法，发现 LN 杂合女性的 TGrPBL 频率范围为 1 × 10−3 至 5 × 10−2，而 LN 男性的血液样本显示 TGr 细胞为 23% 至 100%。在与正常细胞的人工混合物中可以检测到稀有的 LN PBL。对接受各种潜在诱变疗法的人类患者进行的研究评估了这些疗法对非 LN 个体的 TGrPBL 变异频率 (Vf) 的影响。接受治疗的患者组的 TGrPBL Vf 值高于对照组。然而，一些未经治疗的患者组（癌症和牛皮癣）的值也升高，表明疾病本身可能会影响 TGrPBL 频率。尽管如此，一组患者（白癜风）在接受治疗的患者（8-甲氧基补骨脂素和长程紫外线 = PUVA）中表现出 Vf 值升高，但在未经治疗的患者中则没有，这表明治疗是造成 TGrPBL 升高的原因。对接受 X 射线治疗的癌症患者进行的长期纵向研究表明，此类暴露也与 TGrPBL 频率升高有关，并表明可能有必要进行纵向研究以将 TGrPBL V 感觉与特定环境影响联系起来。在大鼠外周血中发现了与人类相似的变异 TGrPBL 频率。在用临床烷化剂治疗动物后，它们在一项研究中有所增加。TGrPBL 的表征表明其中一些细胞是突变体。据推测，突变细胞是通过体细胞突变在体内产生的。在当前测定（表型）的条件下，似乎还有一群非突变细胞掺入 3 H-胸苷。目前的努力旨在采取措施将表型与突变的 PBL 区分开来。放射自显影方法被认为是一种可能能够在人体中直接进行致突变性测试的方法。建议通过将连续致突变性测试结果与接受潜在致突变治疗的患者的最终临床结果相关联来测试其价值以及体细胞突变与人类健康的相关性。
Direct in vivo tests of somatic cell mutation in man may provide realism in assessing the genetic risks of potential environmental mutagens. The autoradiographic determination of purine analogue (8‐azaguanine; 6‐thioguanine) resistant (AGr; TGr) peripheral blood lymphocytes (PBLs) arising in vivo in man is proposed as a candidate test. PBLs bearing the naturally occurring Lesch‐Nyhan (LN) mutation are prototype mutant cells. LN PBLs are AGrand TGr, whereas normal PBLs are AG and TG sensitive.When judged by the inhibition of phytohemagglutinin (PHA) stimulated3H‐thymidine incorporation in vitro, analogue‐resistant LN PBLs may be distinguished from analogue‐sensitive normal PBLs by several methods. Early studies quantitating PHA stimulation by scintillation spectrometry detected down to 1% of LN PBLs in artificial mixtures with normal PBLs. Although LN heterozygous females could be identified on the basis of lymphocyte mosaicism, scintillation spectrometry was too insensitive to detect rare “LN‐like” PBLs in non‐LN individuals. Autoradiography, however, detected rare TGrPBLs in normal non‐LN individuals. Their frequencies did not increase with age. With this method, TGrPBL frequencies in LN heterozygous females were found to range from 1 × 10−3to 5 × 10−2, whereas blood samples from LN males showed from 23% to 100% TGrcells. Rare LN PBLs could be detected in artificial mixtures with normal cells.Studies in human patients undergoing various potential mutagenic therapies assessed the effects of these therapies on the TGrPBL variant frequencies (Vf) of non‐LN individuals. Group TGrPBL Vfvalues were higher in treated patient groups than in controls. However, some untreated patient groups (cancer and psoriasis) also had elevated values, suggesting that disease itself may affect TGrPBL frequencies. Nonetheless, one patient group (vitiligo) showed elevated Vfvalues in treated (8‐methoxypsoralen and long‐range UV light = PUVA) but not in untreated patients, suggesting that treatment was responsible for the TGrPBL elevations. Longitudinal studies over time in cancer patients receiving X‐irradiation therapy demonstrated that such exposures also are associated with TGrPBL frequency rises and suggested that longitudinal studies may be necessary to relate TGrPBL Vfelevations to specific environmental influences.Variant TGrPBLs were found at frequencies comparable to those in man in the peripheral blood of rats. They increased in a single study following treatment of the animals with a clinical alkylating agent.Characterization of the TGrPBLs suggests that some of these cells are mutants. Presumably the mutant cells arise in vivo by somatic cell mutation.There also appears to be a population of nonmutant cells that incorporate3H‐thymidine under conditions of the current assay (phenocopies). Current efforts are directed at measures that will allow phenocopies to be distinguished from mutant PBLs.The autoradiographic method is presented as one potentially capable of direct mutagenicity testing in man. It is suggested that its value for this, and the relevance of somatic cell mutation to human health, be tested by correlating sequential mutagenicity test results with eventual clinical outcomes in patients receiving potentially mutagenic treatments.