Obtained when experiments were repeated (data not shown). WT and TLR22/2 mice infected with either strain had similar levels of bacteremia (Fig. 2). Interestingly, mean levels of 104 CFU/mL were uniformly observed 6 days p.i. for both strains in WT and TLR22/2 mice, without the presence of clinical signs.Expression of several mouse genes after S. suis infection by the ST1 strain, but not by the ST7 strain, partially depends on TLRTo investigate survival differences observed between WT and TLR22/2 mice infected with the ST1 strain but not between mouse counterparts infected with the ST7 strain, a whole genome microarray study was undertaken. As shown in Table S1, several genes were upregulated in WT and TLR22/2 mice at 6 h p.i. by both strains when compared to mock-infected mice. Several ofFigure 1. Absence of TLR2 increases survival following infection with S. suis Nafarelin highly virulent strain ST1 but not with the epidemic strain ST7. Survival of 7-week-old C57BL/6 mice (n = 13 mice per infection group) or TLR22/2 mice (n = 14 mice per infection group) inoculated by intraperitoneal injection with 16107 CFU of either P1/7 strain (ST1; panel A) or SC84 strain (ST7; panel B) was monitored for 72 h. * P,0.01, indicates statistically significant differences between infected WT and TLR22/2 mouse groups, as determined by Log-rank (Mantel-Cox) test. doi:10.1371/journal.pone.0065031.gTLR2-Independent Activation by S. suisFigure 2. Blood bacteremia of S. suis highly virulent strain ST1 and epidemic strain ST7 is similar in C57BL/6 and TLR22/2 mice. C57BL/6 mice (n = 13 mice per group) or TLR22/2 mice (n = 14 mice per group) were inoculated by intraperitoneal injection with 16107 CFU of either S. suis strain P1/7 (ST1) or SC84 (ST7). At 6 h (panel A), day 1 (panel B), day 3 (panel C), and day 6 (panel D) post-infection, 5 ml of blood was harvested from the tail of infected mice and proper dilutions were plated on blood agar plate to assess blood bacteremia. Data of individuals are presented including geometric mean with 95 confidence interval. No significant differences (P.0.05) between infected TLR22/2 mice and their WT counterpart were observed as determined by ANOVA. doi:10.1371/journal.pone.0065031.gthese genes were related to proinflammatory cytokines, chemokines, and signaling pathways. Interestingly, this induction was generally lower in TLR22/2 infected mice, particularly in mice infected with the ST1 strain. Many proinflammatory (-)-Calyculin A chemokines (such as CCL2, CCL3, CCL4, CCL7, CCL11, CXCL1, and CXCL2) were up-regulated to a lower level in TLR22/2 mice infected with the ST1 strain than in WT counterparts. In contrast, no significant differences in the level of CCL2, CCL3, CCL4, CCL7, CCL11, CXCL1, and CXCL2 were observed between TLR22/2 and WT mice infected with ST7 strain. Surprisingly, no significant differences in the up-regulation levels of IL-6 and TNF, two important cytokines involved in sepsis, were observed by microarray between TLR22/2 and WT mice infected with either of the strains (Table S1). Reduction in the expression levels of several proinflammatory genes in ST1-infected TLR22/2 mice compared to WT counterparts, but not in those infected with the ST7 strain, wasconfirmed by qRT-PCR. A significant reduction in the levels of CCL3, CCL4, CXCL1, CXCL2, and CCL2 gene expression in TLR22/2 mice infected with the highly virulent ST1 strain compared to WT infected mice was observed (Fig. 3A ). Different from the results obtained by microarra.Obtained when experiments were repeated (data not shown). WT and TLR22/2 mice infected with either strain had similar levels of bacteremia (Fig. 2). Interestingly, mean levels of 104 CFU/mL were uniformly observed 6 days p.i. for both strains in WT and TLR22/2 mice, without the presence of clinical signs.Expression of several mouse genes after S. suis infection by the ST1 strain, but not by the ST7 strain, partially depends on TLRTo investigate survival differences observed between WT and TLR22/2 mice infected with the ST1 strain but not between mouse counterparts infected with the ST7 strain, a whole genome microarray study was undertaken. As shown in Table S1, several genes were upregulated in WT and TLR22/2 mice at 6 h p.i. by both strains when compared to mock-infected mice. Several ofFigure 1. Absence of TLR2 increases survival following infection with S. suis highly virulent strain ST1 but not with the epidemic strain ST7. Survival of 7-week-old C57BL/6 mice (n = 13 mice per infection group) or TLR22/2 mice (n = 14 mice per infection group) inoculated by intraperitoneal injection with 16107 CFU of either P1/7 strain (ST1; panel A) or SC84 strain (ST7; panel B) was monitored for 72 h. * P,0.01, indicates statistically significant differences between infected WT and TLR22/2 mouse groups, as determined by Log-rank (Mantel-Cox) test. doi:10.1371/journal.pone.0065031.gTLR2-Independent Activation by S. suisFigure 2. Blood bacteremia of S. suis highly virulent strain ST1 and epidemic strain ST7 is similar in C57BL/6 and TLR22/2 mice. C57BL/6 mice (n = 13 mice per group) or TLR22/2 mice (n = 14 mice per group) were inoculated by intraperitoneal injection with 16107 CFU of either S. suis strain P1/7 (ST1) or SC84 (ST7). At 6 h (panel A), day 1 (panel B), day 3 (panel C), and day 6 (panel D) post-infection, 5 ml of blood was harvested from the tail of infected mice and proper dilutions were plated on blood agar plate to assess blood bacteremia. Data of individuals are presented including geometric mean with 95 confidence interval. No significant differences (P.0.05) between infected TLR22/2 mice and their WT counterpart were observed as determined by ANOVA. doi:10.1371/journal.pone.0065031.gthese genes were related to proinflammatory cytokines, chemokines, and signaling pathways. Interestingly, this induction was generally lower in TLR22/2 infected mice, particularly in mice infected with the ST1 strain. Many proinflammatory chemokines (such as CCL2, CCL3, CCL4, CCL7, CCL11, CXCL1, and CXCL2) were up-regulated to a lower level in TLR22/2 mice infected with the ST1 strain than in WT counterparts. In contrast, no significant differences in the level of CCL2, CCL3, CCL4, CCL7, CCL11, CXCL1, and CXCL2 were observed between TLR22/2 and WT mice infected with ST7 strain. Surprisingly, no significant differences in the up-regulation levels of IL-6 and TNF, two important cytokines involved in sepsis, were observed by microarray between TLR22/2 and WT mice infected with either of the strains (Table S1). Reduction in the expression levels of several proinflammatory genes in ST1-infected TLR22/2 mice compared to WT counterparts, but not in those infected with the ST7 strain, wasconfirmed by qRT-PCR. A significant reduction in the levels of CCL3, CCL4, CXCL1, CXCL2, and CCL2 gene expression in TLR22/2 mice infected with the highly virulent ST1 strain compared to WT infected mice was observed (Fig. 3A ). Different from the results obtained by microarra.