Cytokine expression is modified by a single CpG injection in WT and IL-18BP^−/−mice. WT and IL-18BP^−/− male mice were sacrificed either 4 (H4, n = 7 per genotype) or 24 hours (H24, n = 7 or 8 per genotype) after a single CpG injection. These mice were compared with naive WT (n = 8) and IL-18BP^−/− (n = 7) male mice (H0). (A) Il18 and Il18bp, (B) Ifnγ, (C) Cxcl9, and (D) CIIta mRNA levels were assessed in the spleen (left) and liver (middle), and serum levels of (A) free IL-18, (B) IFN-γ, and (C) CXCL9 were measured (right). For each time point, data were pooled from 2 independent experiments. The Mann-Whitney U test was used to compare WT and IL-18BP^−/− mice at each time point and to compare naive and CpG-challenged mice.