Results
Lack of TLR11 Leads to Enhanced Susceptibility to Infection by S. Typhimurium
Although we had previously suggested that the PAMP from UPECs recognized by TLR11 was a protein (Zhang et al., 2004), our initial efforts to identify the ligand were unfruitful. We suspected that TLR11 was likely to recognize similar ligands in other pathogenic bacteria, and to help identify additional pathogens that might trigger TLR11-dependent responses, we examined the tissue distribution of TLR11. We carried out RT-PCR to examine TLR11 expression in liver, spleen, kidney, heart, and intestine and observed high relative expression of TLR11 in the small intestine (Figure 1A and Figure S1A available online). We examined the expression of TLR11 in sections from the small intestine by using in situ hybridization. Similar to the pattern of expression seen in the urinary bladder, TLR11 messenger RNA (mRNA) was strongly enriched in the epithelial layer of the small intestine (Figures 1B and S1B).