Soluble components of Hericium erinaceum induce NK cell activation via production of interleukin-12 in mice splenocytes

Abstract

Aim: To investigate the immunoregulatory functions of water extracts of Hericium erinaceum (WEHE) focusing on natural killer (NK) cell-based anticancer activities. Methods: Mouse splenocytes or purely isolated NK cells were stimulated with 1-100 mg/L WEHE for 24 h followed by co-culture with 51Cr-labled Yac-1 cells for 4 h, then NK cell-derived cytolytic activity was measured using a radio-release assay. Neutralizing antibodies against mouse interleukin-12 (IL-12) were added into the WEHE-stimulated splenocytes, thereafter, cytotoxicity was measured to examine the involvement of IL-12. RT-PCR and ELISA analyses were performed to confirm the induction of transcription and the translation of IL-12 and interferon-gamma (IFN-gamma) in the WEHE-treated splenocytes. Results: WEHE enhanced the cytolytic activity of total splenocytes towards Yac-1 cells in a dose-dependent manner. However, this activation was not observed when the NK cells isolated from the splenocytes were treated with WEHE. Furthermore, the treatment with antibodies against IL-12 abolished the effect of WEHE on splenocyte-derived cytolytic activity. RT-PCR and ELISA analyses showed the induction of IL-12 and IFN-gamma in the WEHE-treated splenocytes. Conclusion: WEHE indirectly activates the cytolytic ability of NK cells via the induction of IL-12 in total splenocytes, and possibly via other immuno-mediators or cellular components. © 2007 CPS and SIMM.