TLR4 and infection: The use of an EHEC O157: H7 (438/99) strain containing enterohemolysin, γ-intimin, T3SS, Stx, and pO157 plasmid virulence factors may have contributed to its colonization36–40 and the innate immune hallmarks, including the increased transcription of IL8 in the ileum and TLR4 in RAJs in infected calves in the early infection (7 d post-challenge).