Research Paper Volume 13, Issue 5 pp 7199—7210
APDL1-CART cells exhibit strong PD-L1-specific activity against leukemia cells
- 1 Department of Haematology, Quanzhou First Hospital of Affiliated to Fujian Medical University, Quanzhou 362000, China
Received: July 14, 2020 Accepted: December 18, 2020 Published: February 26, 2021https://doi.org/10.18632/aging.202578
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Copyright: © 2021 Peng et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Chimeric antigen receptor (CAR) T cells target specific tumor antigens and lyse tumor cells in an MHC-independent manner. However, the efficacy of CAR-T cell and other cancer immunotherapies is limited by the expression of immune-checkpoint molecules such as programmed death-ligand 1 (PD-L1) on tumor cells, which binds to PD-1 receptors on T cells leading to T cell inactivation and immune escape. Here, we incorporated a PD-L1-targeted single-chain variable fragment (scFv) fusion protein sequence into a CAR vector to generate human anti-PD-L1-CAR-T cells (aPDL1-CART cells) targeting the PD-L1 antigen. Unlike control T cells, aPDL1-CART cells significantly halted the expansion and reduced the viability of co-cultured leukemia cells (Raji, CD46, and K562) overexpressing PD-L1, and this effect was paralleled by increased secretion of IL-2 and IFN-γ. The antitumor efficacy of aPDL1-CART cells was also evaluated in vivo by co-injecting control T cells or aPDL1-CART cells along with PDL1-CA46 cells to generate subcutaneous xenografts in NCG mice. Whereas large tumors developed in mice inoculated with PDL1-CA46 cells alone or together with control T cells, no tumor formation was detected in xenografts containing aPDL1-CART cells. Our data suggest that immune checkpoint-targeted CAR-T cells may be useful for controlling and eradicating immune-refractory hematological malignancies.