Comparison of flow cytometric analysis and [3H]thymidine incorporation for measurement of the effects of drug toxicity on lymphocyte stimulation.

Human mononuclear cells were exposed to three antiviral agents, stimulated with phytohemagglutinin, and assayed for DNA synthesis with [3H]thymidine uptake and flow cytometric analysis. Cytosine-arabinoside demonstrated inhibition of blastogenic reactivity by both [3H]thymidine uptake and flow cytometric analysis, whereas acyclovir showed no significant suppression. In contrast, (E)-5-(2-bromovinyl)-2'-deoxyuridine, a thymidine analog, demonstrated a lack of correlation between the two methods. The competitive inhibition of some compounds with [3H]thymidine incorporation necessitates the use of other methods to measure DNA synthesis.