Reducing Ex Vivo Culture Improves the Antileukemic Activity of Chimeric Antigen Receptor (CAR) T Cells

Cancer Immunol Res. 2018 Sep;6(9):1100-1109. doi: 10.1158/2326-6066.CIR-17-0405. Epub 2018 Jul 20.


The success of chimeric antigen receptor (CAR)-mediated immunotherapy in acute lymphoblastic leukemia (ALL) highlights the potential of T-cell therapies with directed cytotoxicity against specific tumor antigens. The efficacy of CAR T-cell therapy depends on the engraftment and persistence of T cells following adoptive transfer. Most protocols for T-cell engineering routinely expand T cells ex vivo for 9 to 14 days. Because the potential for engraftment and persistence is related to the state of T-cell differentiation, we hypothesized that reducing the duration of ex vivo culture would limit differentiation and enhance the efficacy of CAR T-cell therapy. We demonstrated that T cells with a CAR-targeting CD19 (CART19) exhibited less differentiation and enhanced effector function in vitro when harvested from cultures at earlier (day 3 or 5) compared with later (day 9) timepoints. We then compared the therapeutic potential of early versus late harvested CART19 in a murine xenograft model of ALL and showed that the antileukemic activity inversely correlated with ex vivo culture time: day 3 harvested cells showed robust tumor control despite using a 6-fold lower dose of CART19, whereas day 9 cells failed to control leukemia at limited cell doses. We also demonstrated the feasibility of an abbreviated culture in a large-scale current good manufacturing practice-compliant process. Limiting the interval between T-cell isolation and CAR treatment is critical for patients with rapidly progressing disease. Generating CAR T cells in less time also improves potency, which is central to the effectiveness of these therapies. Cancer Immunol Res; 6(9); 1100-9. ©2018 AACR.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, CD19 / genetics
  • Antigens, CD19 / immunology
  • Antigens, Neoplasm / immunology
  • Cell Culture Techniques*
  • Cell Differentiation / immunology
  • Cell Line, Tumor
  • Cytotoxicity, Immunologic
  • Humans
  • Immunotherapy, Adoptive*
  • Lymphocyte Activation
  • Mice
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / immunology*
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / therapy*
  • Receptors, Chimeric Antigen / immunology
  • T-Lymphocytes / immunology
  • Time Factors
  • Xenograft Model Antitumor Assays


  • Antigens, CD19
  • Antigens, Neoplasm
  • CD19 molecule, human
  • Receptors, Chimeric Antigen