Identification of aneuploidy-inducing agents using cytokinesis-blocked human lymphocytes and an antikinetochore antibody.

The identification of agents causing aneuploidy in humans, a condition associated with carcinogenesis and birth defects, is currently limited due to the highly skilled and time-consuming nature of cytogenetic analyses. We report the development of a new simple and rapid assay to identify aneuploidy-inducing agents (aneuploidogens). The assay involves the chemical- or radiation-induced formation of micronuclei in cytokinesis-blocked human lymphocytes and the use of an antikinetochore antibody to determine whether the micronuclei contain centromeres--a condition indicating a high potential for aneuploidy. All agents tested produced dose-related increases in the frequency of micronucleated cells. The micronucleated cells induced by the known aneuploidogens--colchicine, vincristine sulfate, and diethylstilbestrol--contained kinetochore-positive micronuclei 92, 87, and 76% of the time, respectively. In contrast, the micronucleated cells induced by the potent clastogens--ionizing radiation and sodium arsenite--contained kinetochore-positive micronuclei only 3 and 19% of the time, respectively. These results indicate that this relatively simple assay can discriminate between aneuploidogens and clastogens and may allow a more rapid identification of environmental and therapeutic agents with aneuploidy-inducing potential.