O6-methylguanine-DNA methyltransferase activities from exponentially growing human T lymphocytes: similar activities in controls and Alzheimer's disease patients

Abstract

O6-Methylguanine-DNA methyltransferase (MT) specific activity (fmol/mg protein) was measured in human T lymphocytes which were maintained as exponentially growing cultures from 6 to 17 days. The T lymphocytes were not transformed and were grown under the same conditions used previously for determination of spontaneous human mutant frequencies. Although large inter-individual differences in activity were found, the differences were not attributable to donor age, sex or time in culture. The reported specific activity results, including the age and sex independence, were similar to other laboratories even though non-cultured peripheral blood T lymphocytes were previously used. Since cells from Alzheimer's disease (AD) patients have been shown to be overly sensitive to alkylation damage induced by N-methyl-N'-nitro-N-nitrosoguanine, and since no one has previously assayed MT activity in cells from AD patients, we compared MT activities in cultured T lymphocytes from AD patients, healthy controls and neurological controls. Similar levels of MT specific activity were found in each category analysed.