TNF and infection: Concordantly with our findings of induced inflammatory cytokines reported elsewhere [47], 4-week-old weaned conventional piglets orally-infected with S. Typhimurium showed upregulation of TLR2 and TLR4 in the ileum that resulted in the expression of pro-inflammatory cytokine IL-1β, IL-6, and TNF-α mRNA expressions 2 days post-infection [91].