Effects of Selenium In Vitro on Human T-Lymphocyte Functions and K-562 Tumor Cell Growth

Abstract

In vitro E-rosette formation, lymphocyte mitogenesis, and natural killer (NK) cell activity of human blood lymphocytes were strongly inhibited by high concentrations (10⁻⁴ M) of sodium selenite, sodium selenate, and selenium dioxide. Lower concentrations (10⁻⁵ or 10⁻⁷ M) also inhibited E-rosette formation and natural killer cell activity against K-562 tumor cells. Lymphocyte transformation induced by concanavalin A (con A) or pokeweed mitogen (PWM) was also inhibited by all selenium compounds tested, but only at the highest concentrations (10⁻⁵ and 10⁻⁴ M). There was depression of the total number of viable lymphocytes following incubation with selenium dioxide only at a high concentration (10⁻⁴ M). Interferon production was enhanced at lower levels (10⁻⁹ to 10⁻⁶M) of selenium dioxide while a higher concentration (10⁻⁵ and 10⁻⁴M) appeared to inhibit its production. The mechanism of inhibition by selenium compounds (10⁻⁴ M) is due, in part, to the decrease of viable lymphocytes. It is unclear how other and lower concentrations (10⁻⁷ or 10⁻⁹ M) of selenium compounds inhibit E-rosette formation, NK activity, or K-562 tumor cell growth.