Myeloid Conditioning with c-kit-Targeted CAR-T Cells Enables Donor Stem Cell Engraftment

作者：Yasuyuki Arai, Uimook Choi, Cristina Corsino, Sherry Koontz, Masaki Tajima, Colin L. Sweeney, Mary A. Black, Steven A. Feldman, Mary C. Dinauer, Harry L. Malech · 发表于：Molecular Therapy · 年份：2018 · DOI：10.1016/j.ymthe.2018.03.003 · 被引用次数：62 · 研究领域：CAR-T cell therapy research、Pluripotent Stem Cells Research、Biomedical Ethics and Regulation

We report a novel approach to bone marrow (BM) conditioning using c-kit-targeted chimeric antigen receptor T (c-kit CAR-T) cells in mice. Previous reports using anti-c-kit or anti-CD45 antibody linked to a toxin such as saporin have been promising. We developed a distinctly different approach using c-kit CAR-T cells. Initial studies demonstrated in vitro killing of hematopoietic stem cells by c-kit CAR-T cells but poor expansion in vivo and poor migration of CAR-T cells into BM. Pre-treatment of recipient mice with low-dose cyclophosphamide (125 mg/kg) together with CXCR4 transduction in the CAR-T cells enhanced trafficking to and expansion in BM (<1%–13.1%). This resulted in significant depletion of the BM c-kit + population (9.0%–0.1%). Because congenic Thy1.1 CAR-T cells were used in the Thy1.2-recipient mice, anti-Thy1.1 antibody could be used to deplete CAR-T cells in vivo before donor BM transplant. This achieved 20%–40% multilineage engraftment. We applied this conditioning to achieve an average of 28% correction of chronic granulomatous disease mice by wild-type BM transplant. Our findings provide a proof of concept that c-kit CAR-T cells can achieve effective BM conditioning without chemo-/radiotherapy. Our work also demonstrates that co-expression of a trafficking receptor can enhance targeting of CAR-T cells to a designated tissue.