Abstracts (complete list) - Wissenschaft Online

Esther Wilk, Katy Kalippke, Sabine Buyny, Reinhold E Schmidt, Roland Jacobs
Response of CD56 dim and CD56 bright NK cells to Interleukin 21
IL-21 is a cytokine with pleiotropic effects on various cell types including DC, B, T, and
NK cells. In order to evaluate the effects of IL-21 on human NK cell subpopulations
functional studies were completed on CD56 dim and CD56 bright NK cells, both bearing IL-
21 receptors at identical densities. Stimulation with IL-21 strongly induced proliferation
of CD56 bright NK cells. Cytotoxicity against K562 target cells was preferentially
augmented in CD56 dim whereas the expression of granzyme K increased mainly in
CD56 bright NK cells. Intracellular analysis of STAT proteins revealed IL-21 induced
phosphorylation of STAT1 and STAT3 in CD56 dim NK cells, and to an even higher degree
in CD56 bright NK cells. In the CD56 bright NK cell population, IL-2 led to a slight
phosphorylation of STAT1 and 3, which was synergistically increased when cells were
treated with IL-2 and IL-21 in combination. STAT5 was strongly phosphorylated in
CD56 bright NK cells by low dose IL-2, while IL-21 did not affect STAT5. Our data
indicates that the NK cell directed cytokines IL-2 and IL-21 not only differently affect
functions in NK cell subpopulations but can also act in a synergistic fashion.
Supported by DFG Priority Program SPP1110, project Ja1058.