Optimizing CAR‐NK Cell Transduction and Expansion: Leveraging Cytokine Modulation for Enhanced Performance

Abstract Cellular immunotherapy has emerged as one of the most potent approaches to treating cancer patients. Adoptive transfer of chimeric antigen receptor (CAR) T cells as well as the use of haploidentical natural killer (NK) cells can induce remission in patients with lymphoma and leukemia. Although the use of CAR T cells has been established, this approach is currently limited for wider use by the risk of severe adverse events, including cytokine release syndrome and immune effector cell‐associated neurotoxicity syndrome. Moreover, the risk of triggering graft vs host reactions in settings of allogeneic T cell infusion limits the use to autologous CAR T cells if advanced CRISPR engineering is not applied. In contrast, NK cell‐based cancer immunotherapy has emerged as a safe approach even in allogeneic settings. However, efficient transduction of primary blood NK cells with vesicular stomatitis virus G glycoprotein (VSV‐G) pseudotyped lentivirus commonly used for T cell modification remains challenging. This article presents a detailed method that significantly enhances the transduction efficiency of NK cells by utilizing a short‐term culture in cytokine‐supplemented medium. It also encompasses the preparation of high‐titer and high‐quality lentiviral particles for optimal NK cell transduction. Overall, this protocol details the step‐by‐step culture of NK cells in cytokine‐supplemented medium, their transduction with VSV‐G lentiviral vectors, and subsequent expansion for functional assays. © 2024 Wiley Periodicals LLC. Basic Protocol 1 : Isolation of NK cells from human peripheral blood mononuclear cells (PBMCs) Basic Protocol 2 : NK cell expansion and transduction with lentivirus for generating CAR‐NK cells Support Protocol 1 : Plasmid amplification Support Protocol 2 : Lentivirus preparation Support Protocol 3 : Lentivirus titration