The Effect of Interleukin 2 and Transforming Growth Factor-β2 (TGF-β2) on the Proliferation and Natural Killer Activity of Decidual CD16 - CD56 bright Natural Killer Cells

Abstract

The present study, using flow cytometry, demonstrated that CD16 - CD56 bright natural killer (NK) cells, which are abundant in the decidua, have both interleukin-2 receptor alpha (IL-2Rα) and interleukin-2 receptor beta (IL-2Rβ). The NK activity and DNA synthesis of CD16 - CD56 bright NK cells were markedly elevated even by treatment with small amounts of IL-2. These results indicate that decidual CS16 - CD56 bright NK cells possess a high-affinity receptor for IL-2. Transforming growth factor-β2 (TGF-β2), which is contained in the decidua and is thought to serve as a major immunosuppressive factor, reduced the NK activity of decidual CD16 - CD56 bright NK cells, but it hardly affected the IL-2-induced augmentation of the NK activity or DNA synthesis of decidual CD16 - CD56 bright NK cells. The conclusion has therefore been reached that once IL2 is produced in the decidua, the IL-2-induced potentiation of the NK activity of decidual CD16 - CD56 bright NK cells cannot be suppressed by TGF-β2.