TLR4 and viral infectious disease: Prominent ligands that activate or inhibit TLR4 include lipid VI‐A and its derivatives (lipid 4A [antagonist], monophosphoryl lipid A [MPLA, a weak agonist],108 and glucopyranosyl lipid adjuvant [GLA, an agonist]),109 and recent studies have also evaluated antibody or peptide‐based drugs.105, 110 Among the TLRs, TLR4 has been extensively evaluated in the highest number of clinical trials and is of interest as a target for treatment of a variety of pathologies including cancers, viral infection, immune diseases, and inflammation.