Selenium supplementation enhances the expression of interleukin 2 receptor subunits and internalization of interleukin 2.

Selenium (Se) is an essential nutritional factor that was shown previously by us to alter the kinetics of expression of high affinity (p55/p75) interleukin 2 receptors (IL-2R). This study shows that dietary (2 ppm for 8 weeks) or in vitro (1 x 10(-7) M) supplementation with Se (as sodium selenite) results in a significant upregulation of the expression of both the p55 and p70/75 IL-2 binding sites on the surface of concanavalin A-stimulated lymphocytes from C57BL/6J mice. This resulted in the formation of significantly higher numbers of high affinity IL-2R/cell with preservation of the normal ratio of high affinity to total IL-2 binding sites/cell. The high affinity IL-2R on cells from Se-supplemented animals functioned normally in terms of ligand binding and kinetics of IL-2 internalization, but their greater numbers/cell resulted in the internalization of significantly larger amounts of IL-2/cell. As Se supplementation results in an earlier expression of greater numbers of high affinity IL-2R, the presence of Se in the cell environment can result in an accelerated clonal expansion of activated lymphocytes.