The Effects of Treatment with Human β-Interferon on the Stimulation of Thymidine Uptake and DNA Synthesis by Colchicine in Human Fibroblasts

The marked inhibition by beta-interferon (IFN) of colchicine-induced incorporation of [3H]-thymidine into DNA of human fetal lung fibroblasts reflects inhibition of uptake of labeled precursor, rather than an effect on DNA synthesis per se. The percent of cells in S phase as measured with flow cytometry was unchanged by a concentration of IFN that reduced the uptake of labeled thymidine by 50% at 30 h after treatment.