Effect of Frentizole on Mitogen-Induced Blastogenesis in Human Lymphocytes

Frentizole is a new immunoregulatory agent developed as an alternative to cytotoxic agents. In human lymphocytes, Frentizole inhibits the response to various phytomitogens without decreasing cell viability. Frentizole (500 ng/ml) inhibited thymidine incorporation into DNA most effectively when added to lymphocyte cultures at the same time as the addition of the mitogen. Frentizole (500 ng/ml) markedly inhibited the response to Con A (% inhibition, (58%) to PHA (30%) and to PWM (39%). Inhibition of thymidine incorporation was dose dependent with 125 ng/ml of Frentizole sufficient to inhibit significantly the response of all three mitogens. Frentizole (62.5 ng/ml) maximally inhibited uridine incorporation, and inhibition of uridine incorporation was independent of the phytomitogen employed. Increasing concentrations of Frentizole were found to have no effect on thymidine or uridine incorporation into unstimulated normal lymphocytes.