Activation of NK cells by Newcastle disease virus hemagglutinin-neuraminidase

摘要

The avian paramyxovirus Newcastle disease virus (NDV) selectively replicates in tumor cells and is known to stimulate NK cell-mediated responses. The mechanisms of NK cell activation by NDV are poorly understood. Here we studied the expression of ligand structures for activating NK cell receptors on NDV-infected tumor cells. Upon infection with NDV, human and murine tumor cells showed enhanced expression of ligands for the natural cytotoxicity receptors NKp44 and NKp46, but not NKp30. The hemagglutinin-neuraminidase (HN) of NDV serves as ligand structure for NKp44 and NKp46 as indicated by the blockade of binding to NDV-infected cells with anti-HN antibodies. NK cells lysed NDV-infected tumor with enhanced efficiency suggesting that direct activation of NK cells contributes to the anti-tumor effects of NDV.