Protease-activated receptor 2 (PAR-2) is expressed in various tissues， including lung， and when activated， promotes inflammation， differentiation， and migration of dendritic cells. We found that combining influenza virosomes containing hemagglutinin and neuraminidase with a PAR-2 agonist peptide (PAR-2AP) in an intranasal prime boost approach increased survival of mice challenged weeks later with lethal influenza virus over that by virosome or PAR-2AP prime boost alone. No weight loss occurred from influenza challenge after virosome-plus-PAR-2AP prime boost compared with either virosomes or PAR-2AP alone. Thus， virosomes plus PAR-2AP prevented morbidity as well as mortality. Through adoptive transfer， CD8 lung T cells but not CD4 T cells from virosomes plus PAR-2AP-primed mice protected from lethal influenza virus challenge and enhanced survival with less weight loss and faster recovery. Virosome-plus-PAR-2AP prime boost resulted in greater percentages of T effector memory phenotype cells (Tem) in lung， and higher frequencies of CD8 Tem and T central memory cells displayed effector functions in response to virus challenge in vivo. Virosome-plus-PAR-2AP prime boost also resulted in greater percentages of Ag-specific CD8 T cells， both Tem and T central memory cells， in lungs of animals subsequently challenged with live influenza virus. Our findings indicate that PAR-2AP， a short peptide， may be a new and useful mucosal adjuvant.