TLR4 and Salmonella Infections: In addition, we also observed that challenging Salmonella significantly enhanced the mRNA expressions of TLR4 and NF-ΚB (Figure 1C); protein expressions of TLR4 and p-NF-ΚB/NF-ΚB were also higher in the Salmonella infection group compared with the control group (Figure 1D).