Successful treatment of cancer with adoptive immunotherapy (AIT) is dependent on the ability to produce large numbers of tumor-specific, functional T cells. The purpose of this thesis is to explore ways in which T cell expansion could be augmented. We have focused on exploring alternate gamma chain cytokines as stimulators of T cell proliferation and differentiation in addition to investigating the potential usefulness of gemcitabine (GEM) in abrogating the immunosuppressive effects of myeloid derived suppressor cells (MDSCs). B16 melanoma sensitized draining lymph node cells that have been activated in vitro with bryostatin-1 and ionomycin (B/I) were expanded in either IL-7/15 or in IL-2. We found that IL-7/15 was superior to IL-2 in expanding T cells for AIT of pulmonary metastases. Expansion of antitumor T cells was also improved by suppressing accumulation of MDSCs in mice bearing 4T1 mammary carcinoma using GEM. GEM directly inhibits both 4T1 mammary carcinoma cells and MDSCs. Its inhibition of MDSCs rescued tolerant T cells, augmenting both expansion and response to tumor antigen.