FIG. 1.

NOD1 is required for resistance to infection with L. monocytogenes in vivo. The course of infection with L. monocytogenes in NOD1^−/− and WT mice was analyzed. Mice were infected i.p. (A to D) or i.v. (E and F) with 10⁵ (A to C), 2 × 10⁴ (E and F), or 2 × 10³ (D) L. monocytogenes CFU and sacrificed at indicated time points (A, B, E, and F) or 4 days after infection (D). The mean L. monocytogenes CFU titers in livers and spleens of six mice per group are shown. The error bars indicate standard errors of the means (SEM). *, P < 0.05 for a comparison with WT mice (Student's t test). (C) Cumulative mortality of NOD1^−/− and WT mice (eight mice per group) after i.p. infection with 10⁵ L. monocytogenes CFU. (G) Numbers of L. monocytogenes CFU in the snout, trigeminal nerve (TG), and brain of six NOD1^−/− mice and six WT mice 4 days after infection via the snout. The bacterial loads are expressed in CFU per g of tissue (mean ± standard error of the mean). The differences between the NOD1^−/− and WT groups are significant for all tissues except the snout (P < 0.05, Student's t test; indicated by an asterisk).