Our laboratory is investigating the immune response to tumors in murine models. We have recently adapted new tumor-antigen cloning methodology to the identification of the T-cell antigen present in the murine WP-6 tumor. We have validated this system in a test model, and have currently screened approximately half of a c-DNA library from WP-6. We have pursued optimization of a chimeric T-cell receptor recognizing a human ovarian carcinoma antigen in collaboration with Patrick Hwu, M.D. We have completed in vivo models demonstrating the efficacy of this receptor inserted into murine tumor-infiltrating lymphocytes (TIL) in the treatment of human ovarian carcinoma in nude mice, and murine tumors transduced with the ovarian carcinoma antigen in syngeneic mice. We have recently cloned the previously identified murine B7.2 co-stimulatory molecule, and produced a variety of retroviral and recombinant vaccinia constructs which have been utilized to introduce this co-stimulatory molecule into murine tumors. Experiments are ongoing to demonstrate its effect on antitumor immunization, and the production of immune cells for therapy. In the clinical area, two major on-going randomized trials are being conducted. The first one is investigating the use of doxorubicin and ifosfamide in the adjuvant setting for high-grade extremity sarcoma. The second study, for which an interim report has just been accepted for publication, is examining the relative efficacy of IL-2 given by high- and low-dose intravenous routes, or subcutaneous outpatient administration. Over 160 patients have been randomized in this trial, and it is on-going. In a continuation of lymphocyte traffic studies in patients with melanoma receiving tumor-infiltrating lymphocytes, we have begun investigating the circulatory kinetics of these cells as they traverse capillary beds of the body. A combination of labeled cells and nuclear medicine scanning has demonstrated that the vast majority of TIL arrest in the pulmonary capillary bed on their first circulatory passage. The implications of this in antitumor response is being studied.
