Disclosed are means, methods and compositions of matter useful for induction of natural killer cell memory by administration of dendritic cells and/or exosomes thereof. In one embodiment a mammal suffering from cancer is administered allogeneic cord blood derived dendritic cells that are not pulsed exogenously. In one embodiment the dendritic cells are stimulated to possess chemotactic activity towards the tumor by culture of dendritic cell progenitors in hypoxia. Natural killer cell memory is induced, in part, by triggering of upregulation of cytokines associated with homeostatic expansion such as interleukin 7 and interleukin 15.