A trial of adoptive immunotherapy was performed in which long-term cultured, interleukin-2 (IL2)-dependent T-lymphocytes were administered to patients with metastatic adenocarcinoma of the lung. Lymphocytes were isolated from explants of cancer tissues that were cultured in medium with recombinant IL-2. These T-cells expressed surface markers of activation, and killed a broad panel of tumor targets. Intravenously injected 111indium-labeled T-cell blasts distributed primarily to lungs, liver, and spleen. Despite a paucity of infused lymphocytes detected by external imaging at sites of tumor, five of seven patients showed reduction of their cancers. However, in no case was greater than 50% reduction of total tumor burden achieved. Evidence of increased delayed cutaneous hypersensitivity to protein antigens was observed in three patients following therapy. We conclude that long-term cultured tumor-derived T-cells can be transferred safely into humans and that these cells may be capable of enhancing immune responses and mediating tumor reduction in vivo.