2003 AACR Abstract

In Vivo Localization and Efficacy of Adoptively Transferred Tim-3 Positive Tumor Specific TH1 Cell Clones

W. J. Simmons¹,², M. Koneru², M. Mohindru³, R. Thomas², S. Cutro¹, P. Singh¹, G. Inghirami², A. Coyle⁴, B. S. Kim³, N. M. Ponzio¹

¹UMDNJ - NJ Med Sch & Grad Sch Biomed Sci, ²NYU Sch of Med, ³Northwestern U Sch of Med, ⁴Millennium Pharmaceuticals

Human B cell neoplasms are often infiltrated with activated CD4+ T cells, yet their function is unclear. The very existence of neoplasms in these patients indicates that these T cells failed to support a tumor-specific cytotoxic immune response. The B cell neoplasms that arise in SJL mice contain activated T cells that produce TH2 cytokines (IL-4 & IL-5) that promote tumor growth. Another cytokine, IL-12, inhibits TH2 cytokine production by T cells but induces IFN-g production. To exploit this property, Phase 2 trials have been conducted using IL-12 therapy in cancer patients. Positive responses were observed in some patients but toxicities and mortalities halted these trials. In the SJL model, daily injections of up to 2 mg IL-12 had no effect on tumor growth. However, addition of IL-12 to cultures of naïve T cells stimulated by irradiated tumor cells caused the appearance of cytotoxic cells that killed tumor target cells. Therefore, we repeatedly stimulated naïve T cells with tumor cells in the presence of IL-12 to produce tumor-responsive TH1 cell clones. The TH1 cell clones expressed surface Tim-3, CD4, and CD30. In addition, mRNA for T-bet, but not GATA-3, was transcribed by the TH1 cell clones. Intracellular and secreted cytokine analysis revealed increased IFN-g, but minimal IL-4 production. The TCR b chain of the TH1 cell clones was consistently skewed towards a single V b, due to stimulation by the superantigen expressing tumor cells. Functionally, the TH1 clones proliferated in response to tumor cells (but not allogeneic cells), replaced the need for IL-12 in the in vitro development of cytotoxicity against neoplastic target cells, but did not lyse targets directly. To determine if the TH1 cell clones functioned in vivo, 5x106 CFSE labeled TH1 cell clones were injected iv into young mice. Spleen sections from these mice showed localization of CFSE+ cells in the T cell zones of the white pulp. The CFSE+ cells did not co-localize with CD19+ cells (in the same sections) but localized around and outside of the B cells. In contrast to vehicle injected mice, young SJL mice that received Tim-3+ TH1 cell clones prior to challenge with viable tumor and had reduced tumor burden and a decreased absolute number of tumor cells in their lymphoid organs. In addition, mice that received a single dose of 5x106 cloned Tim-3+ TH1 cells rarely developed neoplasms (7% incidence) by 12 months of age, a time at which 90% of SJL mice typically exhibit tumors. Overall, these data indicate that SJL mice can develop tumor-specific cytotoxicity following adoptive transfer of Tim-3+ tumor specific TH1 cell clones, which provides a novel strategy for development of immunotherapy for cancer patients.