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Evidence-Based Complementary and Alternative Medicine
Volume 2015, Article ID 603198, 11 pages
http://dx.doi.org/10.1155/2015/603198
Research Article

Interferon-γ-Mediated Natural Killer Cell Activation by an Aqueous Panax ginseng Extract

1Division of Cell Biology, Biomedical Research Center, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan
2Department of Biofunctional Microbiota, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan
3Atopy (Allergy) Research Center, Graduate School of Medicine, Juntendo University, Bunkyo-ku, Tokyo 113-8421, Japan
4Department of Immunology, Juntendo University School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan

Received 31 July 2015; Revised 20 October 2015; Accepted 26 October 2015

Academic Editor: Nunziatina De Tommasi

Copyright © 2015 Kazuyoshi Takeda and Ko Okumura. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Panax ginseng extracts are used in traditional herbal medicines, particularly in eastern Asia, but their effect on natural killer (NK) cell activity is not completely understood. This study aimed to examine the effects of P. ginseng extracts on the cytotoxic activity of NK cells. We orally administered P. ginseng extracts or ginsenosides to wild-type (WT) C57BL/6 (B6) and BALB/c mice and to B6 mice deficient in either recombination activating gene 2 (RAG-2) or interferon-γ (IFN-γ). We then tested the cytotoxic activity of NK cells (of spleen and liver mononuclear cells) against NK-sensitive YAC-1 cells. Oral administration of P. ginseng aqueous extract augmented the cytotoxicity of NK cells in WT B6 and BALB/c mice and in RAG-2-deficient B6 mice, but not in IFN-γ-deficient B6 mice. This effect was only observed with the aqueous extract of P. ginseng. Interestingly, the ginsenosides Rb1 and Rg1 did not augment NK cell cytotoxicity. These results demonstrated that the aqueous P. ginseng extract augmented NK cell activation in vivo via an IFN-γ-dependent pathway.