Improved in vivo efficacy of tumor-infiltrating lymphocytes after restimulation with irradiated tumor cells in vitro.
ABSTRACT We investigated different culture conditions for tumor-infiltrating lymphocytes (TILs) with regard to proliferation, phenotypic changes, in vitro cytotoxicity, and in vivo therapeutic efficacy.
After enzymatic digestion of the murine fibrosarcoma, MCA-105, TIL cultures were initiated as pure lymphocyte (groups 1 and 2) or mixed lymphocyte/tumor suspensions (groups 3 and 4). Group I TILs were grown in culture medium containing 100 IU/ml recombinant interleukin-2 (rIL-2). Group 2 TILs were stimulated with solid-phase anti-CD3 monoclonal antibody (mAb) for 48 h and cultured in rIL-2 (100 IU/ml)-containing medium. Group 3, which consisted initially of a surplus of tumor cells, received the same treatment as group 2. Group 4 was also activated with anti-CD3 mAb and rIL-2 but was additionally restimulated weekly with irradiated tumor cells (TILs to tumor, 20:1).
Groups 1 and 2 showed up to twofold higher increases in TIL numbers compared with groups 3 and 4 by the end of culture week 5. Although the original lymphocyte/tumor cell suspension consisted of 12.0 +/- 3.8% CD4+ T cells and 5.3 +/- 3.3% CD8+ T cells, all four TIL cultures showed approximately 80% CD8+ TILs and no CD4+ TILs by the end of culture week 4. In vitro cytotoxicity did not correlate with in vivo efficacy of the examined TIL cultures. By using the MCA-105 pulmonary metastases model in C57BL/6 mice, only suboptimal doses of TILs (2 x 10(6)) from group 4, which had been restimulated weekly with irradiated tumor, showed significant tumor eradication compared with all other treatment groups (p < 0.01).
We conclude that in vitro tumor restimulation of TILs improves in vivo efficacy, most likely through the education of tumor-reactive T cells.
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ABSTRACT: Adoptive cell transfer (ACT) immunotherapy administered with prior host immunosuppression significantly improved the anti-tumor efficacy in a murine model. However, bulk transfer of lymphocytes containing suppressor lymphocyte subsets, including regulatory T cells to mice bearing late-stage tumors impaired this anti-tumor effect. In this study, we investigated the enhanced anti-tumor efficacy by adoptive transfer of Treg-depleted autologous tumor infiltrating lymphocytes in advanced murine breast cancer. We found that, compared to bulk cell transfer, Treg-depleted cell transfer enhanced the activation and proliferation of both CD4(+) and CD8(+) T cells. Most importantly, the immune response deviated towards the Th1 response reflected by increased IFNgamma and reduced IL-4 secretion in both CD4(+) and CD8(+) T cells and an enhanced granzyme B release of CTL. Furthermore, the elicited Th1 response subsequently resulted in delayed tumor growth and prolonged mice survival as well as reduced lung metastasis in tumor-bearing nude mice. These results strongly indicated that Treg-depleted autologous cell transfer greatly enhanced Th1 type immune response, consequently leading to delayed tumor growth and reduced tumor burden. Therefore, ACT immunotherapy based on ex vivo selection of tumor-reactive lymphocytes resulted in enhanced anti-tumor immunity and provides important implications for further human studies.Cancer biology & therapy 02/2009; 8(1):66-72. · 3.29 Impact Factor
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ABSTRACT: The tumor-associated-Ag MART-1 is expressed by most human melanomas. The genes encoding an alphabeta TCR from a MART-1-specific, HLA-A2-restricted, human T cell clone have been efficiently transferred and expressed in human PBL. These retrovirally transduced PBL cultures were MART-1 peptide reactive, and most cultures recognized HLA-A2+ melanoma lines. Limiting dilution clones were generated from three bulk transduced PBL cultures to investigate the function of individual clones within the transduced cultures. Twenty-nine of 29 CD8+ clones specifically secreted IFN-gamma in response to T2 cells pulsed with MART-1(27-35) peptide, and 23 of 29 specifically secreted IFN-gamma in response to HLA-A2+ melanoma lines. Additionally, 23 of 29 CD8+ clones lysed T2 cells pulsed with the MART-1(27-35) peptide and 15 of 29 lysed the HLA-A2+ melanoma line 888. CD4+ clones specifically secreted IFN-gamma in response to T2 cells pulsed with the MART-1(27-35) peptide. TCR gene transfer to patient PBL can produce CTL with anti-tumor reactivity in vitro and could potentially offer a treatment for patients with metastatic melanoma. This approach could also be applied to the treatment of other tumors and viral infections. Additionally, TCR gene transfer offers unique opportunities to study the fate of adoptively transferred T cells in vivo.The Journal of Immunology 08/1999; 163(1):507-13. · 5.36 Impact Factor
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ABSTRACT: The purpose of this review is to illustrate some of the technical and biological hurdles that need to be addressed when developing new gene therapy based clinical trials. Gene transfer approaches can be used to "mark" cells to monitor their persistence in vivo in patients, to protect cells from toxic chemotherapeutic agents, correct a genetic defect within the target cell, or to confer a novel function on the target cell. Selection of the most suitable vector for gene transfer depends upon a number of factors such as the target cell itself and whether gene expression needs to be sustained or transient. The TCR gene transfer approach described here represents one innovative strategy being pursued as a potential therapy for metastatic melanoma. Tumor reactive T cells can be isolated from the tumor infiltrating lymphocytes (TIL) of melanoma patients. A retroviral vector has been constructed containing the T cell receptor (TCR) alpha and beta chain genes from a MART-1-specific T cell clone (TIL 5). Jurkat cells transduced with this virus specifically release cytokine in response to MART-1 peptide pulsed T2 cells, showing that the virus can mediate expression of a functional TCR. HLA-A2 transgenic mice are being used to examine whether transduced bone marrow progenitor cells will differentiate in vivo into mature CD8+ T cells expressing the MART-1-specific TCR. Expression of the human TCR alpha and beta chain genes has been detected by RT-PCR in the peripheral blood of HLA-A2 transgenic mice reconstituted with transduced mouse bone marrow. Expression of the TIL 5 TCR genes in the peripheral blood of these mice was maintained for greater than 40 weeks after bone marrow reconstitution. TIL 5 TCR gene expression was also maintained following transfer of bone marrow from mice previously reconstituted with transduced bone marrow to secondary mouse recipients, suggesting that a pluripotent progenitor or lymphocyte progenitor cell has been transduced.Pathology & Oncology Research 02/1999; 5(1):3-15. · 1.81 Impact Factor