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