IL-18 metabolically reprograms CAR-expressing natural killer T cells and enhances their antitumor activity

  • Mol Ther. 2026 Jan 10:S1525-0016(26)00001-8. doi: 10.1016/j.ymthe.2026.01.001.
Gabriel A Barragán Bravo  1 ,  David A de la Cerda  1 ,  Elisa Landoni  2 ,  Kshiti Dholakia  1 ,  Piotr Humeniuk  1 ,  Leidy D Caraballo Galva  1 ,  Ying Wang  1 ,  Gengwen Tian  1 ,  Boning Yang  1 ,  Linjie Guo  1 ,  Michael S Wood  1 ,  Xavier Rios  1 ,  Xin Xu  1 ,  Amy N Courtney  1 ,  Erica J Di Pierro  1 ,  Joan Jacob  1 ,  Yi-Han Li  1 ,  Akshaya Adaikkalavan  1 ,  Norihiro Watanabe  3 ,  Sufeng Mao  4 ,  George Miles  5 ,  Gianpietro Dotti  2 ,  Leonid S Metelitsa  6
Affiliations
  • 1. Center for Advanced Innate Cell Therapy, Texas Children's Cancer Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA.
  • 2. Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA.
  • 3. Center for Advanced Innate Cell Therapy, Texas Children's Cancer Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA.
  • 4. Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX 77030, USA.
  • 5. Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.
  • 6. Center for Advanced Innate Cell Therapy, Texas Children's Cancer Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA. Electronic address: [email protected].
PMID: 41520178 DOI: 10.1016/j.ymthe.2026.01.001
Abstract

Invariant natural killer T cells (NKTs) have intrinsic antitumor properties that make them promising candidates for chimeric antigen receptor (CAR) immunotherapies. Transgenic cytokine expression can enhance cellular therapy potency, and we hypothesized that co-expressing interleukin-18 (IL-18) alone or with IL-15 would boost CAR-NKT therapeutic potential. To test this, we generated retroviral constructs expressing IL-15 and/or IL-18 with an inducible caspase-9 safety switch and co-transduced them with a GD2-specific CAR into human NKTs. Co-expression of IL-18 or IL-15/IL-18 increased CAR-NKT cytotoxicity, proliferation, and cytokine secretion in vitro compared to IL-15 alone. IL-18 also enhanced GPC3.CAR and CD19.CAR NKT activity against hepatocellular carcinoma and B cell leukemia cells, respectively. In a metastatic Neuroblastoma model, IL-18-expressing GD2.CAR-NKTs controlled Tumors more effectively than IL-15-only cells, but mice in the IL-15/IL-18 group developed severe toxicities not observed in the IL-18-only group. Mechanistically, IL-18 induced a transcriptional program distinct from IL-15, marked by lower exhaustion signatures and enrichment of metabolic pathways. Finally, targeted metabolomics showed that IL-18 drives broad metabolic reprogramming in CAR-NKTs including increased Oxidative Phosphorylation, Glycolysis, glutaminolysis, and Purine Metabolism. These findings support the use of IL-18 in developing the next generation of cytokine-armed CAR-NKT Cancer immunotherapies.

Keywords
CAR; IL-15; IL-18; metabolism; natural killer T cell; neuroblastoma.
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