Abstract: Immune cells and cancer cells that can internalize nanoplexed poly(I:C) formulations more efficiently, and are therefore more effectively modified by such formulations, are presently characterized both in vitro and in vivo using novel labeled nanoplexed poly(I:C) formulations. The internalizing of the disclosed formulations by the cells allows the defining of specific medical indications and/or subject patient populations, in particular in subjects presenting cancer, in addition to the identification of preferred routes and regimens for beneficially administering a nanoplexed poly(I:C) formulation, alone or in combination with other drugs, to achieve desired therapeutic outcomes for such patients.