Provided herein are (1) a method of mixing an aluminum salt-adsorbed immunogen with a monophosphoryl lipid A (MPLA)-containing liposome (L(MPLA)), and (2) the resulting immunogenic composition. The resulting immunogenic composition has an enhanced immunostimulation potency compared with either a composition comprising the uncapsulated immunogen mixed with the L(MPLA) or the aluminum salt-adsorbed immunogen alone.