H5N1 AIV induce IFN in chicken splenocytes. Splenocytes were stimulated with various doses of AIV for 24 h. In (A), live and BEI-inactivated Vac and Yama viruses are shown. In (B), Vac and Yama are compared with the reassortants Vac-Y/HA and Yama-V/HA. In (C), various natural isolates of LPAIV and HPAIV are shown. IFN was quantified by bioassay. The averages of triplicate cultures with standard deviations are shown. The * indicates statistical differences calculated with the students t-test (p < 0.05). The results are representative for at least three independent experiments.