The invention is directed to methods and compositions for cell-based targeted delivery of predetermined compounds to a population of target cells. In some embodiments, methods of the invention include providing cytotoxic lymphocytes genetically modified to produce and sequester in lytic granules fusion proteins comprising a granzyme, or other effector agent, and a predetermined protein, so that upon specific contact of the cytotoxic lymphocytes with the target cells, the granzyme-perforin pathway of the cytotoxic lymphocytes is activated, leading to the delivery of the fusion protein to the cytosols of the target cells.
