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Natural killer (NK) cells play a vital role in innate immunity and show great promise in cancer immunotherapy. Traditional sources of NK cells, such as the peripheral blood, are limited by availability and donor variability. In addition, in vitro expansion can lead to functional exhaustion and gene editing challenges. This study aimed to harness induced pluripotent stem cell (iPSC) technology to provide a consistent and scalable source of NK cells, overcoming the limitations of traditional sources and enhancing the potential for cancer immunotherapy applications. We developed human placental–derived iPSC lines using reprogramming techniques. Subsequently, an optimized two‐step differentiation protocol was introduced to generate high‐purity NK cells. Initially, iPSCs were differentiated into hematopoietic‐like stem cells using spin‐free embryoid bodies (EBs). Subsequently, the EBs were transferred to ultra‐low attachment plates to induce NK cell differentiation. iPSC‐derived NK (iNK) cells expressed common NK cell markers (NKp46, NKp30, NKp44, CD16 and eomesodermin) at both RNA and protein levels. iNK cells demonstrated significant resilience to cryopreservation and exhibited enhanced cytotoxicity. The incorporation of a chimeric antigen receptor (CAR) construct further augmented their cytotoxic potential. This study exemplifies the feasibility of generating iNK cells with high purity and enhanced functional capabilities, their improved resilience to cryopreservation and the potential to have augmented cytotoxicity through CAR expression. Our findings offer a promising pathway for the development of potential cellular immunotherapies, highlighting the critical role of iPSC technology in overcoming challenges associated with traditional NK cell sources. [ABSTRACT FROM AUTHOR]

There is significant clinical interest in targeting adenosine-mediated immunosuppression, with several small molecule inhibitors having been developed for targeting the A2AR receptor. Understanding of the mechanism by which A2AR is regulated has been hindered by difficulty in identifying the cell types that express A2AR due to a lack of robust antibodies for these receptors. To overcome this limitation, here an A2AR eGFP reporter mouse is developed, enabling the expression of A2AR during ongoing anti-tumor immune responses to be assessed. This reveals that A2AR is highly expressed on all tumor-infiltrating lymphocyte subsets including Natural Killer (NK) cells, NKT cells, γδ T cells, conventional CD4+ and CD8+ T lymphocytes and on a MHCIIhiCD86hi subset of type 2 conventional dendritic cells. In response to PD-L1 blockade, the emergence of PD-1+A2AR- cells correlates with successful therapeutic responses, whilst IL-18 is identified as a cytokine that potently upregulates A2AR and synergizes with A2AR deficiency to improve anti-tumor immunity. These studies provide insight into the biology of A2AR in the context of anti-tumor immunity and reveals potential combination immunotherapy approaches. Adenosine is an immunosuppressive metabolite known to limit anti-tumor immune responses. Here the authors report the characterization of an adenosine A2A receptor (A2AR) eGFP reporter mouse, providing immunological insights into the biology of A2AR expression in the context of anti-tumor immunity. [ABSTRACT FROM AUTHOR]

Keywords: chimeric antigen receptor T cells; cytotolytic CD4+ T cells; persistence EN chimeric antigen receptor T cells cytotolytic CD4+ T cells persistence 304 307 4 05/05/22 20220501 NES 220501 In a recently published article, Melenhorst I et al i . performed a longitudinal analysis on chimeric antigen receptor (CAR) T cells isolated from patients over 10 years after therapy, revealing expansion of a long-lived CD4 SP + sp CAR T-cell population with a cytotoxic phenotype. (a) The anti-CD19 CAR T-cell response can be subdivided into the acute phase (Phase I) where CAR T cells initially expand and subsequently contract in line with reduced numbers of CD19+ cells (either tumor cells or healthy B cells). Consistent with this observation, T-cell receptor sequencing analysis demonstrated little clonality in persisting CAR T cells, suggesting this may be more stochastic than previously anticipated. [Extracted from the article]