Regulatory effects of interleukin-4 on tumor-infiltrating lymphocytes derived from human renal cell carcinoma

Abstract

We have studied the effects of interleukin-4 (IL-4) on the expansion, proliferation, phenotype, and antitumor activity of tumor-infiltrating lymphocytes (TIL) derived from human renal cell carcinoma. Cultures were obtained from three primary renal tumors and one group of tumor-invaded, regional lymph nodes. IL-4 induced a significant increase in lymphocyte expansion and proliferation, but the response was dependent on the concurrent dose of IL-2 in culture. Increased growth activity was only observed in those cultures receiving low doses (20 U/ml) of IL-2 (average increase of fold expansion of 6.5, P < 0.01) with no changes in growth activity in the high dose (1000 U/ml) cultures. The combination of low dose IL-2 and IL-4 (200 U/ml) promoted lymphocyte growth significantly better than high dose IL-2 alone, the current standard growth regimen for in vitro expansion of TIL. TIL grown in the presence of IL-4 significantly reduced the level of nonspecific, non-major histocompatibility complex-restricted antitumor activity ( P < 0.01 for allogeneic renal, nonrenal, and NK-sensitive K562 cells), while exhibiting no effect on the level of autologous killing. This is in contrast to previous findings of significant enhancement of autologous antitumor activity using IL-4 on tumor-specific, melanoma-derived TIL. We also evaluated the effects of irradiated autologous tumor stimulation (TIL:tumor ratio, 10:1) on TIL cultures. Addition of autologous tumor cells increased expansion and proliferation of all cultures regardless of concurrent lymphokines present in the culture media (average increase fold expansion of 2.21, P < 0.05). In addition, significantly enhanced levels of autologous killing were observed in some cultures after the addition of autologous tumor cells (3.4 and 5.9 lytic units without and with autologous tumor stimulation, respectively, P < 0.02). Therefore, the greatest total fold expansion was seen in those cultures containing the combination of IL-4, low dose IL-2, and irradiated autologous tumor cells, which when compared to the standard TIL growth condition of 1000 U/ml of IL-2 alone exhibited a 5.22 ± 2.44 greater fold expansion. Our results suggest that IL-4 and autologous tumor stimulation are effective growth factors, when used in combination with a low dose IL-2 regimen, and may be of significant benefit for growing activated TIL from patients with renal cell carcinoma (RCC). Furthermore, the different biologic properties and responses to exogenous lymphokines of TIL derived from RCC versus other histologically distinct neoplasms suggests the need for an individualized approach in determining the optimal regimen for the expansion and activation of these cells.