EVALUATION OF: Araki K, Turner AP, Shaffer VO et al. mTOR regulates memory CD8 T-cell differentiation. Nature 460(7251), 108-112 (2009). The prime goal of vaccination is to induce an effective memory T-cell response, because memory T cells have a pivotal role in adaptive immunity. When a specific pathogen is encountered after vaccination, memory immune cells induce an adaptive immune response against that pathogen, which is faster and stronger than a primary immune response. Therefore, the development of a successful vaccine requires a T-cell response of adequate magnitude. Although many vaccines effectively induce protective immune responses against specific pathogens, some vaccines require boosting due to inadequate generation of memory immune cells. It was reported recently that rapamycin, which is used as an immunosuppressive drug for organ transplantation, stimulates the production of memory CD8 T cells. This means that rapamycin or related drugs could be used to enhance the efficacy of many types of vaccines.