[Suppression of DNA synthesis in lymphocytes by UV-irradiated plasma]

The autologous plasma, isolated upon UV-irradiation of the whole blood, has an inhibitory effect on mitogen-induced, blastogenesis of human lymphocytes. Its addition to the culture medium results in a statistically significant suppression of DNA synthesis in lymphocytes in the presence of phytohemagglutinin and concanavalin A. No such effect was observed with the use of pokeweed mitogen. Our studies show that this phenomenon is associated with photoconversion of the plasma components.