Dependence on TLR1 is determined by the route of infection. (A) TLR1^−/−, TLR6^−/−, or heterozygous littermate controls (littermates) were infected orally with 10⁵ CFU Y. enterocolitica strain 8081 and followed for survival. Data are pooled from three individual experiments (n = 5 mice per group for each experiment). Statistical significance was determined by Wilcoxon log-rank test (TLR6^−/−, P < 0.001; TLR1^−/−, P < 0.01). (B) Bacterial burden in MLNs at 3 d after infection. (C) Bacterial burden in the SPLs of orally infected mice 7 d after infection. (D) Survival curve of TLR1^−/−, TLR6^−/−, or littermates infected i.v. with 10⁵ CFU Y. enterocolitica. Data are pooled from three individual experiments (n = 5 mice per group for each experiment). Statistical significance was determined by Wilcoxon log-rank test (TLR6^−/−, P < 0.01). (E) Bacterial burden in the SPL at 3 d after infection. (B, C, and E) Data shown are the mean ± SEM (n = 7). (F) Bacterial burden in SPL 5 d after i.v. infection. Data shown are the mean ± SEM (n = 6). *, P < 0.01; **, P < 0.001 (unpaired Student’s t test).