Our laboratory is investigating ways to improve the efficacy of tumor- infiltrating lymphocytes (TIL), and delineate their mechanism of action in vivo. We have been studying the migration of TIL in response to cytokines and are currently pursuing the purification of a novel, tumor-produced protein with chemotactic activity for TIL and other activated CTL. We have demonstrated in pre-clinical murine models that semi-allogeneic TIL (raised in F1 mice) are therapeutically effective as a prelude to using donor TIL to treat patients with melanoma. We have succeeded in introducing a variety of cytokine genes into murine TIL in order to enhance their efficacy. We have inserted the genes for human TNF and IL- 2, but have encountered an expression block in murine TIL which prevents optimal production of these proteins. This is undergoing further study. In addition, we have introduced a chimeric T-cell receptor into murine TIL which can bind ovarian carcinoma, and are currently proceeding with in vitro and in vivo studies on the interaction of this genetically-altered murine lymphocyte and human ovarian carcinoma. We have also begun a tumor antigen cloning project to identify the tumor antigen recognized by tumor- specific CTL for the murine WP-6 sarcoma, and have completed screening of a portion of the c-DNA library. In the clinical arena, a randomized prospective trial comparing high dose and low dose intravenous IL-2 in the treatment of renal cell carcinoma has accrued approximately 120 patients with similar responses seen in each arm, but significantly lower toxicity present with the low dose IL-2 regimen. This study is currently on-going, and a subcutaneous out-patient IL-2 regimen has been added as the third arm. In addition, a randomized prospective trial on the use of adjuvant chemotherapy with doxorubicin, ifosfamide and GCSF for soft tissue sarcomas of the extremities is underway, and has accrued approximately a dozen patients. A randomized trial investigating the role of adjuvant radiotherapy for low-grade sarcomas is now demonstrating a significant benefit to radio-therapy in the control of local disease, and is on-going.
