During infection, LPS binds to TLR4 on the host cell triggering a cascade of signalling pathways that activate transcription factors such as NF-κβ and interferon-regulatory factors (IRFs) implicated in the expression of genes coding for pro-inflammatory cytokines and chemokines such as cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), IL-1ß, tumour necrosis factor-α (TNF-α), and IL-12. This evidence concerns the gene TLR4 and infection.