In this study, the expression of T-bet and IFN-γ1 showed a significant increase, and subsequently STAT-1 expression was up-regulated at 1 day post-infection with NNVand immuno-stimulation with KLH, whereas slight increases in IL-13 and GATA-3 expression were noted at 3 days post-NNV infection. Here, STAT1 is linked to infection.