ABSTRACT
The tumor-inhibitory effects were dependent on the concentration and repeated injections of interleukin 2 (IL-2). The impact and implications of systemic IL-2 immunotherapy should be briefly evaluated to outline a strategy of selecting tumors suitable for local treatment with IL-2 and clarification of the prospects and limitations of regional IL-2 immunotherapy. IL-2 administration in the immediate tumor vicinity seems to provide certain advantages over systemic administration. Studies performed in authors laboratory on the effector cell mechanism responsible for the antitumor efficacy of local rIL-2 immunotherapy indicated that lymphokine-activated killer (LAK) cells play a decisive role. In some laboratories, LAK cells could be expanded in vitro and kept functional for a period of several months. LAK cells are cytotoxic for a broad spectrum of tumor target cells comprising both Natural Killer (NK)-sensitive and NK-resistant targets. However, monoclonal antibodies against LAK cell-associated antigens have been prepared and these antibodies may serve to better characterize and monitor LAK cells.
