Rapid NK-cell activation in chicken after infection with infectious bronchitis virus M41

Natural killer (NK) cells are cytotoxic lymphocytes and play an important role in the early defence against viruses. In this study we focussed on NK cell and interferon (IFN) responses after infection with infectious bronchitis virus (IBV). Based on surface expression of CD107+, enhanced activation of lung NK cells was observed at 1 dpi, whereas in blood prolonged NK-cell activation was found. IFN-alpha and IFN-beta mRNA and proteins were not rapidly induced whereas IFN-gamma production in lung, measured by Elispot assay, increased over time at 2 and 4 dpi. In contrast, IFN-gamma production in blood was highest at 1 dpi and decreased over time down to levels comparable to uninfected birds at 4 dpi. Collectively, infection with IBV-M41 resulted in activation of NK cells in the lung and blood and rapid production of IFN-gamma and not IFN-alpha and IFN-beta compared to uninfected birds. (C) 2012 Elsevier B.V. All rights reserved.