Immunotherapy of cancer with lymphokine-activated killer cells and recombinant interleukin-2.

Lymphokine-activated killer (LAK) cells can be generated in vitro by incubation of normal murine or human lymphoid cells in recombinant interleukin-2 (RIL-2). These LAK cells are capable of mediating the lysis of fresh, noncultured tumor cells in 4-hour chromium release assays. The adoptive transfer of LAK cells plus RIL-2 is capable of mediating the inhibition of established pulmonary micrometastases from syngeneic tumors in mice. High-dose RIL-2 administered alone is also capable of mediating these antitumor effects, probably via the production of LAK cells in vivo. The immunotherapeutic effect of RIL-2 but not of LAK cells plus RIL-2 is abrogated in hosts that have received preirradiation with 500 rads. The administration of high-dose RIL-2 is also capable of reducing the growth of solid subdermal tumors as well. The use of LAK cells in conjunction with RIL-2 may be applicable to the treatment of cancer in humans, and clinical trials to evaluate this approach in humans have begun.