Inhibition of development and growth of B cell lymphomas by adoptive transfer of Tim-3+ tumor-specific TH1 cells.

NM Ponzio, SJ Simmons, S Cutro, P Singh, G Inghirami, A Coyle, VM Sanders

Human B cell malignancies are often infiltrated with activated CD4⁺ TH cells, yet their function is unclear.  The fact that these cancers exist in such patients indicates that these infiltrating TH cells failed to support a tumor-specific cytotoxic immune response.  The B cell neoplasms that arise in SJL mice contain activated TH2 cells that produce IL-4 and IL-5, which promote tumor growth.  However, use of IL-12 causes a switch in the host response to tumor cells from a TH2 to a TH1 pattern, in which IFN-g is produced instead of IL-4 and IL-5.  Although daily injections of up to 2 mg IL-12 to SJL mice had no effect on tumor growth, addition of IL-12 to co-cultures of naïve SJL spleen cells and irradiated (g-) tumor cells caused the appearance of tumor-specific cytotoxic T lymphocytes (CTL).  Therefore, we repeatedly stimulated naïve T cells with g-tumor cells in the presence or absence of IL-12 to produce tumor-responsive TH1 and TH2 cell clones.  All TH cell clones expressed TH cell markers (TCR, CD3, CD4), but were negative for markers of CTL (CD8) and B cells (sIg, CD19, B220).  TH clones produced in the presence of IL-12 polarized to a TH1 phenotype, and were Tim-3⁺, b-Adrenergic Receptor (b-2AR)⁺, used the T-bet transcription factor, and produced IFN-g.  TH clones produced without IL-12 exhibited a TH2 phenotype, and were T1/ST2⁺, b-2AR^-, used the GATA-3 transcription factor, and produced IL-4.  Functionally, the TH1 clones proliferated in response to tumor cells (but not allogeneic cells),  but did not lyse tumor targets directly. To determine if the TH1 cells could inhibit tumor growth in vivo, TH1 cells were injected iv into young SJL recipients.  Mice that received Tim-3⁺ TH1 cells prior to challenge with viable tumor had reduced tumor burden and a decreased absolute number of tumor cells in their lymphoid organs in comparison to TH2-injected and non-TH cell-injected controls. In addition, young SJL mice that received a single dose of 1x10⁷  Tim-3⁺ TH1 cells rarely developed primary neoplasms (7% incidence) by 12 months of age, a time at which 90% of SJL mice typically exhibit B cell lymphomas. Moreover, histological analysis at 12 months revealed a preservation of lymphoid architecture in the lymphoid tissues of TH1-injected mice in contrast to the total effacement of lymphoid architecture in control mice bearing primary lymphomas. Overall, these data indicate that SJL mice can develop tumor-specific cytotoxicity following adoptive transfer of Tim-3⁺ tumor specific TH1 cells, which provides a novel strategy for development of immunotherapy for cancer patients.