Differential expression of the interleukin 2 receptor beta (p75) chain on human peripheral blood natural killer subsets.

The interleukin-2 receptor (IL-2R) is composed of at least two subunits, the IL-2R alpha (P55, CD25/Tac) and IL-2R beta (p70-75) chains. In the present study we have identified the quantitative expression of IL-2R beta on subsets of NK cells in peripheral blood using flow cytometry and a recently established mAb against IL-2R beta (TU27). We demonstrate that NK cells are not a homogeneous population but that phenotypic subsets exist, and that the levels of IL-2R beta expression correlate with these subsets. The levels of IL-2R beta expression on NK subsets are CD3- CD16- CD56bright NK cells (immature NK) greater than CD16+CD4- NK cells (mature NK) greater than CD16+CD57+ NK cells (more mature NK) in adult peripheral blood lymphocytes. The level of IL-2R beta expression on CD16+ NK cells in cord blood is significantly higher than that in adult PBL. These findings suggest that there may be a inverse relationship between IL-2R beta expression and the differentiation of NK cells. IL-2R beta, preferentially expressed on the NK cells, may play an important role in differentiation and maturation of NK cells.