TLR3 and influenza: It has been shown that the combined use of monophosphoryl lipid A (MPL, a TLR4 agonist) and polyriboinosinic polyribocytidylic acid (poly I:C, a TLR3 agonist) with inactivated A/Puerto Rico/8/1934 (A/PR8) H1N1 influenza vaccine could enhance the protective efficacy against homologous influenza infection and induce significant memory T and B cell responses, minimizing illness outcomes in mouse models [115].