Production of IL-10 by human natural killer cells stimulated with IL-2 and/or IL-12.
Human NK cell activity can be augmented in vitro by stimulation with IL-2 or IL-12, both of which also induce the production of IFN-gamma, TNF-alpha, and granulocyte-macrophage CSF by NK cells. For the first time, we demonstrate that freshly purified NK cells stimulated with IL-2 proliferated and produced IL-10 in a dose-dependent manner. IL-10 mRNA expression, as detected by semiquantitative reverse transcription-PCR, reached peak levels at 24 h. IL-10 protein was detectable on day 2 and further increased on days 3 and 6 as measured by ELISA. However, IL-12 alone induced neither substantial proliferation nor detectable IL-10 production by fresh NK cells, but it synergized with IL-2 in inducing IL-10 mRNA expression and protein synthesis. IL-10 production by activated NK cells was confirmed by intracytoplasmic cytokine staining by three-color immunofluorescence of CD16+ and/or CD56+ NK cells with anti-IL-10 antibody. IL-10 production by NK cells was further confirmed in the NK-like cell line, YT, which constitutively expressed IL-10 mRNA and protein. IL-12 alone did not induce NK proliferation, but it inhibited IL-2-induced proliferation. Neutralization of endogenously produced IL-10 with anti-IL-10 antibodies did not overcome the inhibition of IL-2-induced proliferation by IL-12. Together, these results demonstrate that IL-2 and IL-12 synergize to induce IL-10 production by human NK cells and that IL-12 inhibits IL-2 induced NK cell proliferation by an IL-10-independent mechanism.
Mehrotra
P T
PT
Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, Food and Drug Administration, Rockville, MD 20852-1448, USA.
Donnelly
R P
RP
Wong
S
S
Kanegane
H
H
Geremew
A
A
Mostowski
H S
HS
Furuke
K
K
Siegel
J P
JP
Bloom
E T
ET
D002478:Cells, Cultured; D005434:Flow Cytometry; D006801:Humans; D016753:Interleukin-10 / Q000096:biosynthesis* / Q000235:genetics; D018664:Interleukin-12 / Q000494:pharmacology*; D007376:Interleukin-2 / Q000494:pharmacology*; D007694:Killer Cells, Natural / Q000187:drug effects* / Q000378:metabolism; D008213:Lymphocyte Activation / Q000187:drug effects; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis
D007376:Interleukin-2; D012333:RNA, Messenger; D016753:Interleukin-10; D018664:Interleukin-12