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Cancer Immunol Res. 2018 Apr;6(4):467-480. doi: 10.1158/2326-6066.CIR-17-0207. Epub 2018 Feb 19.

Intrinsic Functional Potential of NK-Cell Subsets Constrains Retargeting Driven by Chimeric Antigen Receptors.

Author information

1
Department of Cancer Immunology, Institute for Cancer Research, Oslo University Hospital, Radiumhospitalet, Norway.
2
The KG Jebsen Centre for Cancer Immunotherapy, Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
3
Department of Immunology, Centre for Biostructure Research, Medical University of Warsaw, Warsaw, Poland.
4
Postgraduate School of Molecular Medicine, Medical University of Warsaw, Warsaw, Poland.
5
Science for Life Laboratory, Department of Applied Physics, KTH-Royal Institute of Technology, Solna, Sweden.
6
Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
7
Department of Clinical Immunology, Transplantation Institute, Medical University of Warsaw, Warsaw, Poland.
8
Department of Oncology, Oslo University Hospital, Oslo, Norway.
9
Department of Cancer Immunology, Institute for Cancer Research, Oslo University Hospital, Radiumhospitalet, Norway. k.j.malmberg@medisin.uio.no.
10
Centre for Infectious Medicine, Department of Medicine Huddinge, Karolinska Institutet, Stockholm, Sweden.

Abstract

Natural killer (NK) cells hold potential as a source of allogeneic cytotoxic effector cells for chimeric antigen receptor (CAR)-mediated therapies. Here, we explored the feasibility of transfecting CAR-encoding mRNA into primary NK cells and investigated how the intrinsic potential of discrete NK-cell subsets affects retargeting efficiency. After screening five second- and third-generation anti-CD19 CAR constructs with different signaling domains and spacer regions, a third-generation CAR with the CH2-domain removed was selected based on its expression and functional profiles. Kinetics experiments revealed that CAR expression was optimal after 3 days of IL15 stimulation prior to transfection, consistently achieving over 80% expression. CAR-engineered NK cells acquired increased degranulation toward CD19+ targets, and maintained their intrinsic degranulation response toward CD19- K562 cells. The response of redirected NK-cell subsets against CD19+ targets was dependent on their intrinsic thresholds for activation determined through both differentiation and education by killer cell immunoglobulin-like receptors (KIR) and/or CD94/NKG2A binding to self HLA class I and HLA-E, respectively. Redirected primary NK cells were insensitive to inhibition through NKG2A/HLA-E interactions but remained sensitive to inhibition through KIR depending on the amount of HLA class I expressed on target cells. Adaptive NK cells, expressing NKG2C, CD57, and self-HLA-specific KIR(s), displayed superior ability to kill CD19+, HLA low, or mismatched tumor cells. These findings support the feasibility of primary allogeneic NK cells for CAR engineering and highlight a need to consider NK-cell diversity when optimizing efficacy of cancer immunotherapies based on CAR-expressing NK cells. Cancer Immunol Res; 6(4); 467-80. ©2018 AACR.

PMID:
29459477
DOI:
10.1158/2326-6066.CIR-17-0207
[Indexed for MEDLINE]

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