SCREENING FOR DEFICITS IN DNA-REPAIR BY RESPONSE OF IRRADIATED HUMAN LYMPHOCYTES TO PHYTOHEMAGGLUTININ

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  • 1 January 1977
    • journal article
    • research article
    • Vol. 37  (10) , 3594-3598
Abstract
An assay was developed to measure the ability of human lymphocytes to repair damage to DNA. In this assay, purified human lymphocytes are exposed to graded doses of radiation and stimulated with phytohemagglutinin to undergo DNA replication. The rate of incorporation of thymidine in irradiated lymphocytes during the 2nd and subsequent rounds of DNA replication is taken to be indicative of the ability of the cells to repair damage to DNA. In lymphocytes from normal individuals, X-irradiation with doses of 100-800 rads was inhibited phytohemagglutinin stimulated thymidine incorporation proportionally to the dose of radiation without curtailing the induction of DNA polymerase. The response to phytohemagglutinin of lymphocytes from a patient with xeroderma pigmentosum after exposure to graded doses of X-irradiation was similar to that of normal controls, whereas the response after UV irradiation was impaired. Lymphocytes from patients with ataxia telangiectasia were hypersensitive to X-irradiation. The data on these clinical syndrome support the idea that this assay measures DNA repair and indicates the feasibility of using this method for screening individuals for genetic deficits in DNA repair which may lead to cancer.