Killing Effects of IFN R ‐/‐ Mouse NK Cells Activated by HN Protein of NDV on Mouse Hepatoma Cells and Possible Mechanism with Syk and NF‐κB

: The objective of this article is to evaluate whether the tumoricidal activity of mouse IFN R-/- nature killer (NK) cells is induced by Newcastle disease virus hemagglutinin-neuraminidase (NDV-HN) stimulation, and to investigate what is the mechanism of the HN-stimulated NK cells to kill mouse hepatoma cell line in vitro. The mouse IFN R-/- NK cells were stimulated for 16 hr with 500 ng/mL NDV-HN in 1640 medium. Quantify the cytotoxic activities of NK cells against mouse hepatoma cells (Hepa1-6) by flow cytometry. Granzymes B (GrB) and Fas/FasL concentrations in the supernatants of IFN R-/- NK cells medium were determined by specific ELISA assay. The expression of cell surface GrB and Fas was determined by Western blot. NDV-HN stimulation enhanced tumoricidal activity of IFN R-/- NK cells toward Hepa1-6 in vitro. Treating with anti-HN neutralizing mAb induced significant decline in the cytotoxicity of IFN R-/- NK cells toward Hepa1-6 cell line (P < 0.05). After treating with anti-HN protein (1 μL/mL), Syk-specific inhibitor Herbimycin A(250 ng/mL) and NF-κB inhibitor PDTC (500 ng/mL) downregulated the tumoricidal activity of HN-stimulated IFN R-/- NK cells (P < 0.05). Moreover, significant suppressions in the production of GrB and Fas/FasL were observed in HN-stimulated IFN R-/- NK cells (P < 0.05). Thus, we concluded that killer activation receptors pathway is involved in the IFN-γ-independent GrB and Fas/FasL expression of NDV-HN-stimulated IFN R-/- NK cells, and these are activated by Syk and NF-κB. Anat Rec, 302:1718-1725, 2019. © 2019 The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association for Anatomy.