DIRECT MUTAGENICITY TESTING IN MAN

该研究项目将调查和改进最近描述的 6-硫鸟嘌呤抗性（TGr）T淋巴细胞（T-Ly）克隆测定 检测人体内发生的体细胞基因突变，以便： (i)提供用于人体内致突变性监测的测定和（ii） 定义这些突变的结构和分子基础。 克隆 将进行更精确的定量分析，然后用于确定 正常个体的TGr T-Ly突变频率值的范围， 暴露于诱变剂的人。 野生型和TGr T-Ly菌落， 从克隆试验中回收的，将表征其表型 稳定性，基因产物改变，T-Ly表面抗原亚类， 染色体改变，hprt基因的DNA结构改变， 在特定的信使RNA和特定的基因的表达， T细胞受体 这些特征将允许定义 人类体内发生的hprt基因突变谱，将提供 最小估计的突变数量负责观察到的 收集突变体，并将确定是否选择突变体 在体内区分“自发”和“诱导”的特征 人体基因突变。 较旧的放射自显影测定法 将定量人外周血中的TGr T-Ly变体频率， 完善，用于人类研究，并使用它获得的结果将是 与使用克隆的类似血液样品获得的结果相比， 比色法 然后将T-Ly克隆测定用作开发的基础。 一种多基因座（即HLA缺失）体细胞突变检测系统， 能够在人体内检测常染色体基因的改变。 将从这些测定中回收的野生型和HLA突变体T-Ly菌落进行克隆。 以类似于表征HPRT突变体的方式表征。

This research project will investigate and improve the recently described 6-thioguanine resistant (TGr) T-lymphocyte (T-Ly) clonal assay for detecting somatic gene mutations occurring in vivo in humans in order to: (i) provide assays for human in vivo mutagenicity monitoring and (ii) define the structural and molecular bases of these mutations. The clonal assay will be made more precisely quantitative and then be used to define the range of TGr T-Ly mutant frequency values for normal individuals and for persons exposed to mutagens. Wild type and TGr T-Ly colonies, recovered from clonal assays, will be characterized as to their phenotypic stability, gene product alterations, T-Ly surface antigen subclass, chromosome change, DNA structural alteration in the hprt gene, alterations in specific messenger RNA and specific configeration of the gene for the T-cell receptor. These characteristics will allow definition of the spectrum of hprt gene mutations occurring in vivo in humans, will provide minimal estimates as to the number of mutations responsible for an observed collection of mutants, and will determine if selected mutant characteristics differentiate between "spontaneous" and "induced" in vivo somatic gene mutations in humans. The older autoradiographic assay for quantitating TGr T-Ly variant frequencies in human peripheral blood will be refined, used for human studies, and results obtained using it will be compared with results obtained for similar blood samples using the clonal assay. The T-Ly clonal assay will then be used as the basis for developing a multi-locus (i.e. HLA-loss) somatic mutation detection system that will be capable of detecting alteration of autosomal genes in vivo in humans. Wild type and HLA mutant T-Ly colonies recovered from these assays will be characterized in a manner analogous to the characterization of hprt mutants.