Anti-Tumor Reactivity of Human Lymphokine Activated Killer (LAK) Cells Against Fresh and Cultured Preparations of Renal Cell Cancer

Abstract

Immunotherapy utilizing the adoptive transfer of lymphokine activated killer (LAK) cells in conjunction with recombinant interleukin-2 (IL-2) is capable of mediating the regression of established cancer in a variety of animal tumor models as well as advanced metastatic cancers in humans. We have thus examined the variability of the anti-tumor lytic reactivity of LAK cells obtained from patients with metastatic renal cell cancer (RCC). Tumor cell suspensions were prepared by enzymatic digestion from 37 consecutive renal cell tumors. The mean (±SEM) total number of cells recovered was 1.5 ± 2.2 × 109 cells per tumor. The percentage of tumor cells in the suspension was 39.1 ± 3.3% (range: 6 to 75%). Thirteen of 13 different fresh renal tumor cell preparations tested in 57 experiments and two of two renal tumor lines tested in 10 experiments were all lysed by LAK cells. RCC patients, like normal donors, generated good LAK effectors with broad antitumor activity against autologous as well as allogenic tumors. Both renal and nonrenal tumors were equally lysed by LAK cells. LAK killing of the erythroleukemic tumor lines K562 and Daudi was significantly better than the lysis of fresh autologous and allogeneic tumor targets or cultured RCC tumor lines. Short term tumor cultures derived from renal cancer preparations proved to be sensitive and reliable tumor targets for studying the in vitro killing by LAK cells. Clinical trials testing the therapeutic role of LAK cells and IL-2 in patients with advanced renal cell cancer are currently in progress.