Fig. 4.

The role of acutely increased IFN-β in induction of IL-6 and sickness behaviour. Plasma IL-6 (a) and IL-6 expression in the hypothalamus and hippocampus (b) of C57BL/6 mice 3 h post-IFN-β challenge (25,000 units, i.p), compared to that induced by poly I:C (12 mg/kg). Data are expressed as mean ± SEM and were analysed by unpaired Student’s t test, n = 4 for WT + vehicle and n = 5 for WT + IFN-β. The sickness behaviour response of C57BL/6 mice to IFN-β (25,000 units, i.p.) on (c) open field activity (expressed as % of baseline squares crossed at 9 h) and (d) burrowing at 7 h. Data are expressed as mean ± SEM and were analysed by Students t-test, n = 17 for WT + vehicle, n = 15 for WT + IFN-β. IL-6 and IFN-β levels in the plasma (e, f) and expression in the hippocampus (g, h) 1 and 3 h post-poly I:C challenge in WT and IFNAR1^−/− mice. Data are expressed as mean ± SEM and were analysed by two-way ANOVA with strain and treatment as factors, n = 5 for WT + saline, n = 4 for WT + pI:C 1 h, n = 5 for WT + pI:C 3 h and n = 4 for IFNAR1^−/− + saline, n = 4 IFNAR1^−/− + pI:C 1 h and n = 5 for IFNAR1^−/− + pI:C 3 h. Bonferroni post-hoc are denoted by ^∗∗∗p < 0.001 and ^∗∗p < 0.001.