Regulatory effects of interleukin-7 on renal tumor infiltrating lymphocytes.

Biological therapy using a combination of lymphokine and tumor infiltrating lymphocytes (TILs) is a new approach to the treatment of patients with advanced cancer. To improve the potency of TILs, new cytokines with T-cell stimulatory effects used alone or in combination with interleukin-2 (IL-2) are currently being investigated. We have studied the effect of interleukin-7 (IL-7) on TILs derived from renal cell carcinoma. Our data demonstrated that five of ten TILs proliferated in response to IL-7 alone. This proliferative response was 73-90% less than that obtained with IL-2 alone. The use of IL-7 plus IL-2 resulted in a 1.2- to 4.7-fold increase in proliferation of six of ten TILs compared with IL-2 alone. IL-7-driven TIL growth was consistently blocked by anti-IL-2, anti-IL-2R and anti-IL-7 antibodies (37.2%, 41.6% and 82.2% suppression, respectively). The expression of IL-2 receptors was also significantly increased in the presence of IL-7 or IL-7 phytohemagglutinin (40.6 + 3.8 and 72.5 + 1.5). In comparison with IL-2, IL-7 treatment was associated with a decrease in CD56 (46.3% +/- 19 vs 10% +/- 4.9) and increase in CD3 (29.3% +/- 12 vs 73% +/- 6.4) and CD4 (19.3% +/- 15 vs 58% +/- 10). These studies suggest that in some renal TILs, IL-7 and IL-2 can have a synergistic proliferative effect. The IL-7 stimulatory effect appears to be mediated via both an IL-2 pathway and an IL-7-independent pathway.