Generation of Melanoma Antigen Specific T Cells From Human Ips Cells Using a Feeder Free System.

Abstract 2292

iPS cells can be induced from various types of somatic cells by reprogramming them using Yamanaka factors (Oct4, Sox2, Klf4, and Myc). They are reported to be very similar to ES cells in many respects, such as gene expression pattern and multipotency. They are expected to be used as a cell source for production of various types of cells to be used in regeneration medicine. In this study, we planned to use iPS cells as a progenitor source for immune cell therapy. For this purpose, iPS cells derived from a lymphocyte that shows a certain antigen-specificity are preferable, because antigen specificity is inherited to iPS cells made from the lymphocyte. For example, if iPS cell are produced from cytotoxic T cells specific to a tumor antigen, T cells generated from these T-iPS can be used in cell therapy for patients bearing cancer.

We have succeeded in establishing iPS cells from human mature T cells (T-iPS cells), namely from whole CD3⁺ cells or CD4⁻CD8⁺ cells of cord blood as well of adult peripheral blood. These T-iPS cells were confirmed to bear productively rearranged TCRβ chain gene. These T-iPS cells were differentiated to CD4⁺CD8⁺ double positive T cells and eventually into CD8⁺ single positive T cells expressing αβTCR in an in vitro co-culture system using OP9-DL1 stromal cells. Such T cell induction occurred more efficiently from T-iPS cells than from human ES cells or from iPS cells derived from other cell types. Sequence analysis of their TCRβ chain suggests that these T cells preserved their original antigen specificity. To confirm that T-iPS cells can generate antigen specific T cells we established T-iPS cells from mature cytotoxic T cells specific to MART-1 (Melanoma antigen recognized by T cells 1) epitope. These MART-1 T-iPS cells were differentiated in vitro until CD4⁺CD8⁺ double positive T cells. By stimulation with anti-CD3 antibody, DP cells generated in vitro from MART1-T-iPS cells turned into a large number of CD8⁺ T cells specific to MART-1, which produced a substantial amount of IFNg upon TCR stimulation. The present study thus provides a novel method for cloning and expanding CD8⁺ T cells specific to a given antigen, which can be potentially applied for cell therapy against cancer.