TLR9-deficient mice showed comparable amounts of IL-12/IL-23p40 and MIP-1α in the spleen 24 h after infection irrespective of CpG ODN treatment: IL-12/IL-23p40 levels in median (25th/75th percentiles) were 160.3 (121.1/182.8) pg/ml in CpG ODN-treated, and 226.8 (151.6/899.3) pg/ml in buffer-treated animals (P = 0.13). This evidence concerns the gene TLR9 and infection.