RT Journal Article SR Electronic T1 Intrinsic Functional Potential of NK-Cell Subsets Constrains Retargeting Driven by Chimeric Antigen Receptors JF Cancer Immunology Research JO Cancer Immunol Res FD American Association for Cancer Research DO 10.1158/2326-6066.CIR-17-0207 A1 Oei, Vincent Yi Sheng A1 Siernicka, Marta A1 Graczyk-Jarzynka, Agnieszka A1 Hoel, Hanna Julie A1 Yang, Weiwen A1 Palacios, Daniel A1 Almåsbak, Hilde A1 Bajor, Malgorzata A1 Clement, Dennis A1 Brandt, Ludwig A1 Önfelt, Björn A1 Goodridge, Jodie A1 Winiarska, Magdalena A1 Zagozdzon, Radoslaw A1 Olweus, Johanna A1 Kyte, Jon-Amund A1 Malmberg, Karl-Johan YR 2018 UL http://cancerimmunolres.aacrjournals.org/content/early/2018/03/11/2326-6066.CIR-17-0207.abstract AB 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); 1–14. ©2018 AACR.