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Malaria, which results from infection with Plasmodium parasites, remains a major public health problem. Although humans do not develop long-lived, sterilizing immunity, protection against symptomatic disease develops after repeated exposure to Plasmodium parasites and correlates with the acquisition of humoral immunity. Despite the established role Abs play in protection from malaria disease, dysregulated inflammation is thought to contribute to the suboptimal immune response to Plasmodium infection. Plasmodium berghei ANKA (PbA) infection results in a fatal severe malaria disease in mice. We previously demonstrated that treatment of mice with IL-15 complex (IL-15C; IL-15 bound to an IL-15Rα-Fc fusion protein) induces IL-10 expression in NK cells, which protects mice from PbA-induced death. Using a novel MHC class II tetramer to identify PbA-specific CD4+ T cells, in this study we demonstrate that IL-15C treatment enhances T follicular helper (Tfh) differentiation and modulates cytokine production by CD4+ T cells. Moreover, genetic deletion of NK cell-derived IL-10 or IL-10R expression on T cells prevents IL-15C-induced Tfh differentiation. Additionally, IL-15C treatment results in increased anti-PbA IgG Ab levels and improves survival following reinfection. Overall, these data demonstrate that IL-15C treatment, via its induction of IL-10 from NK cells, modulates the dysregulated inflammation during Plasmodium infection to promote Tfh differentiation and Ab generation, correlating with improved survival from reinfection. These findings will facilitate improved control of malaria infection and protection from disease by informing therapeutic strategies and vaccine design., (Copyright © 2024 by The American Association of Immunologists, Inc.)

IL-15 has shown preclinical activity by enhancing the functional maturation of natural killer (NK) cells. Clinical evaluation of the potential anticancer activity of most cytokines, including IL-15, has been limited by low tolerability and rapid in vivo clearance. Efbalropendekin Alfa (XmAb24306) is a soluble IL15/IL15-receptor alpha heterodimer complex fused to a half-life extended Fc domain (IL15/IL15Rα-Fc), engineered with mutations to reduce IL-15 affinity for CD122. Reduced affinity drives lower potency, leading to prolonged pharmacodynamic response in cynomolgus monkeys. We show that in vitro , human NK cells treated with XmAb24306 demonstrate enhanced cytotoxicity against various tumor cell lines. XmAb24306-treated NK cells also exhibit enhanced killing of 3D colorectal cancer spheroids. Daratumumab (dara), a monoclonal antibody (mAb) that targets CD38 results in antibody-dependent cellular cytotoxicity (ADCC) of both multiple myeloma (MM) cells and NK cells. Addition of XmAb24306 increases dara-mediated NK cell ADCC against various MM cell lines in vitro . Because NK cells express CD38, XmAb24306 increases dara-mediated NK cell fratricide, but overall does not negatively impact the ADCC activity against a MM cell line likely due to increased NK cell activity of the surviving cells. These data show that XmAb24306 increases direct and ADCC-mediated human NK cell cytotoxicity in vitro ., Competing Interests: All authors are employees and shareholders of Genentech/Roche., (Copyright © 2024 Shehata, Dogra, Gierke, Holder and Sanjabi.)

This study aimed to evaluate the role of skeletal muscle-derived interleukin (IL)-15 in the regulation of skeletal muscle autophagy using IL-15 knockout (KO) and transgenic (TG) mice. Male C57BL/6 wild-type (WT), IL-15 KO, and IL-15 TG mice were used in this study. Changes in muscle mass, forelimb grip strength, succinate dehydrogenase (SDH) activity, gene and protein expression levels of major regulators and indicators of autophagy, comprehensive gene expression, and DNA methylation in the gastrocnemius muscle were analyzed. Enrichment pathway analyses revealed that the pathology of IL-15 gene deficiency was related to the autophagosome pathway. Moreover, although IL-15 KO mice maintained gastrocnemius muscle mass, they exhibited a decrease in autophagy induction. IL-15 TG mice exhibited a decrease in gastrocnemius muscle mass and an increase in forelimb grip strength and SDH activity in skeletal muscle. In the gastrocnemius muscle, the ratio of phosphorylated adenosine monophosphate-activated protein kinase α (AMPKα) to total AMPKα and unc-51-like autophagy activating kinase 1 and Beclin1 protein expression were higher in the IL-15 TG group than in the WT group. IL-15 gene deficiency induces a decrease in autophagy induction. In contrast, IL-15 overexpression could improve muscle quality by activating autophagy induction while decreasing muscle mass. The regulation of IL-15 in autophagy in skeletal muscles may lead to the development of therapies for the autophagy-induced regulation of skeletal muscle mass and cellular quality control. NEW & NOTEWORTHY IL-15 gene deficiency can decrease autophagy induction. However, although IL-15 overexpression induced a decrease in muscle mass, it led to an improvement in muscle quality. Based on these results, understanding the role of IL-15 in regulating autophagy pathways within skeletal muscle may lead to the development of therapies for the autophagy-induced regulation of skeletal muscle mass and cellular quality control.

Background: Chimeric antigen receptor (CAR) T cell therapy has shown remarkable responses in hematological malignancies with several approved products, but not in solid tumors. Patients suffer from limited response and tumor relapse due to low efficacy of CAR-T cells in the complicated and immunosuppressive tumor microenvironment. This clinical challenge has called for better CAR designs and combined strategies to improve CAR-T cell therapy against tumor changes., Methods: In this study, IL-15/IL-15Rα was inserted into the extracellular region of CAR targeting mesothelin. In-vitro cytotoxicity and cytokine production were detected by bioluminescence-based killing and ELISA respectively. In-vivo xenograft mice model was used to evaluate the anti-tumor effect of CAR-T cells. RNA-sequencing and online database analysis were used to identify new targets in residual gastric cancer cells after cytotoxicity assay. CAR-T cell functions were detected in vitro and in vivo after GLI Pathogenesis Related 1 (GLIPR1) knockdown in gastric cancer cells. Cell proliferation and migration of gastric cancer cells were detected by CCK-8 and scratch assay respectively after GLIPR1 were overexpressed or down-regulated., Results: CAR-T cells constructed with IL-15/IL-15Rα (CAR-ss-T) showed significantly improved CAR-T cell expansion, cytokine production and cytotoxicity, and resulted in superior tumor control compared to conventional CAR-T cells in gastric cancer. GLIPR1 was up-regulated after CAR-T treatment and survival was decreased in gastric cancer patients with high GLIPR1 expression. Overexpression of GLIPR1 inhibited cytotoxicity of conventional CAR-T but not CAR-ss-T cells. CAR-T treatment combined with GLIPR1 knockdown increased anti-tumor efficacy in vitro and in vivo., Conclusions: Our data demonstrated for the first time that this CAR structure design combined with GLIPR1 knockdown in gastric cancer improved CAR-T cell-mediated anti-tumor response., (© 2024. The Author(s).)

Background: It remains challenging to obtain positive outcomes with chimeric antigen receptor (CAR)-engineered cell therapies in solid malignancies, like colorectal cancer (CRC) and pancreatic ductal adenocarcinoma (PDAC). A major obstacle is the lack of targetable surface antigens that are not shared by healthy tissues. CD70 emerges as interesting target, due to its stringent expression pattern in healthy tissue and its apparent role in tumor progression in a considerable amount of malignancies. Moreover, CD70 is also expressed on cancer-associated fibroblasts (CAFs), another roadblock for treatment efficacy in CRC and PDAC. We explored the therapeutic potential of CD70 as target for CAR natural killer (NK) cell therapy in CRC, PDAC, focusing on tumor cells and CAFs, and lymphoma., Methods: RNA-seq data and immunohistochemical analysis of patient samples were used to explore CD70 expression in CRC and PDAC patients. In addition, CD70-targeting CAR NK cells were developed to assess cytotoxic activity against CD70 + tumor cells and CAFs, and the effect of cytokine stimulation on their efficacy was evaluated. The in vitro functionality of CD70-CAR NK cells was investigated against a panel of tumor and CAF cell lines with varying CD70 expression. Lymphoma-bearing mice were used to validate in vivo potency of CD70-CAR NK cells. Lastly, to consider patient variability, CD70-CAR NK cells were tested on patient-derived organoids containing CAFs., Results: In this study, we identified CD70 as a target for tumor cells and CAFs in CRC and PDAC patients. Functional evaluation of CD70-directed CAR NK cells indicated that IL-15 stimulation is essential to obtain effective elimination of CD70 + tumor cells and CAFs, and to improve tumor burden and survival of mice bearing CD70 + tumors. Mechanistically, IL-15 stimulation resulted in improved potency of CD70-CAR NK cells by upregulating CAR expression and increasing secretion of pro-inflammatory cytokines, in a mainly autocrine or intracellular manner., Conclusions: We disclose CD70 as an attractive target both in hematological and solid tumors. IL-15 armored CAR NK cells act as potent effectors to eliminate these CD70 + cells. They can target both tumor cells and CAFs in patients with CRC and PDAC, and potentially other desmoplastic solid tumors., (© 2024. The Author(s).)

Background: Preeclampsia, a severe pregnancy syndrome, is widely accepted divided into early- and late-onset preeclampsia (EOPE and LOPE) based on the onset time of preeclampsia, with distinct pathophysiological origins. However, the molecular mechanism especially immune-related mechanisms for EOPE and LOPE is currently obscure. In the present study, we focused on placental immune alterations between EOPE and LOPE and search for immune-related biomarkers that could potentially serve as potential therapeutic targets through bioinformatic analysis., Methods: The gene expression profiling data was obtained from the Gene Expression Omnibus database. ESTIMATE algorithm and Gene Set Enrichment Analysis were employed to evaluate the immune status. The intersection of differentially expressed genes in GSE74341 series and immune-related genes set screened differentially expressed immune-related genes. Protein-protein interaction network and random forest were used to identify hub genes with a validation by a quantitative real-time PCR. Kyoto Encyclopedia of Genes and Genomes pathways, Gene Ontology and gene set variation analysis were utilized to conduct biological function and pathway enrichment analyses. Single-sample gene set enrichment analysis and CIBERSORTx tools were employed to calculate the immune cell infiltration score. Correlation analyses were evaluated by Pearson correlation analysis. Hub genes-miRNA network was performed by the NetworkAnalyst online tool., Results: Immune score and stromal score were all lower in EOPE samples. The immune system-related gene set was significantly downregulated in EOPE compared to LOPE samples. Four hub differentially expressed immune-related genes (IL15, GZMB, IL1B and CXCL12) were identified based on a protein-protein interaction network and random forest. Quantitative real-time polymerase chain reaction validated the lower expression levels of four hub genes in EOPE compared to LOPE samples. Immune cell infiltration analysis found that innate and adaptive immune cells were apparent lacking in EOPE samples compared to LOPE samples. Cytokine-cytokine receptor, para-inflammation, major histocompatibility complex class I and T cell co-stimulation pathways were significantly deficient and highly correlated with hub genes. We constructed a hub genes-miRNA regulatory network, revealing the correlation between hub genes and hsa-miR-374a-5p, hsa-miR-203a-3p, hsa-miR-128-3p, hsa-miR-155-3p, hsa-miR-129-2-3p and hsa-miR-7-5p., Conclusions: The innate and adaptive immune systems were severely impaired in placentas of EOPE. Four immune-related genes (IL15, GZMB, IL1B and CXCL12) were closely correlated with immune-related pathogenesis of EOPE. The result of our study may provide a new basis for discriminating between EOPE and LOPE and acknowledging the role of the immune landscape in the eventual interference and tailored treatment of EOPE., (© 2024 John Wiley & Sons Ltd.)

Natural killer (NK) cells are an important contributor to cancer immunotherapy, but their antitumor efficacy remains suboptimal. While cytokine-based priming shows promise in enhancing NK-cell activity, its clinical translation faces many challenges, including coactivation of multiple cytokines, poor pharmacokinetics, and limited mechanistic understanding. Here, this work develops a polymeric micelle-based IL-15/IL-2 codelivery system (IL-15/2-PEG-PTMC) for NK-cell activation. In vivo studies demonstrate that half-life of IL-15 and IL-2 and the recruitment of NK cell within tumor tissue are significantly increased after PEG-PTMC loading. Coupled with the coactivation effect of IL-15 and IL-2 conferred by this system, it noticeably delays the growth of tumors compared to conventional NK-cell activation approach, that is free IL-15 and IL-2. It is also surprisingly found that cholesterol metabolism is highly involved in the NK cell activation by IL-15/2-PEG-PTMC. Following stimulation with IL-15/2-PEG-PTMC or IL-15, NK cells undergo a series of cholesterol metabolism reprogramming, which elevates the cholesterol levels on NK cell membrane. This in turn promotes the formation of lipid rafts and activates immune synapses, effectively contributing to the enhancement of NK cell's antitumor activity. It is believed that it will open a new avenue for improving the efficacy of NK cell immunotherapy by regulating cholesterol metabolism., (© 2023 Wiley-VCH GmbH.)

NKG2D is an activating receptor of natural killer cells that recognizes stress-induced ligands (NKG2DL) expressed by many tumor cells. Nevertheless, NKG2DL downregulation or shedding can still allow cancer cells to evade immune surveillance. Here, we used lentiviral gene transfer to engineer clinically usable NK-92 cells with a chimeric antigen receptor (NKAR) which contains the extracellular domain of NKG2D for target recognition, or an NKAR, together with the IL-15 superagonist RD-IL15, and combined these effector cells with recombinant NKG2D-interacting bispecific engagers that simultaneously recognize the tumor-associated antigens epidermal growth factor receptor (EGFR) or ErbB2 (HER2). Applied individually, in in vitro cell-killing assays, these NKAB-EGFR and NKAB-ErbB2 antibodies specifically redirected NKAR-NK-92 and NKAR_RD-IL15-NK-92 cells to glioblastoma and other cancer cells with elevated EGFR or ErbB2 levels. However, in mixed glioblastoma cell cultures, used as a model for heterogeneous target antigen expression, NKAR-NK cells only lysed the EGFR- or ErbB2-expressing subpopulations in the presence of one of the NKAB molecules. This was circumvented by applying NKAB-EGFR and NKAB-ErbB2 together, resulting in effective antitumor activity similar to that against glioblastoma cells expressing both target antigens. Our results demonstrate that combining NK cells carrying an activating NKAR receptor with bispecific NKAB antibodies allows for flexible targeting, which can enhance tumor-antigen-specific cytotoxicity and prevent immune escape.

GT-00AxIL15 is a novel interleukin-15-based immunocytokine targeting a tumor-specific, glycosylated epitope of MUC1 (TA-MUC1). We characterized mode of action, pharmacokinetic (PK) and pharmacodynamic (PD) properties and investigated the relevance of TA-MUC1 binding for the concept of delivering IL-15 to solid tumors. In vitro pharmacology was analyzed in binding and cell-based assays. The in vivo PK profile and IL-15-mediated PD effects of GT-00AxIL15 were investigated in tumor-free mice. Tumor accumulation, immune infiltration and anti-tumor activity were assessed in TA-MUC1+ syngeneic and xenogeneic murine tumor models. GT-00AxIL15 was shown to specifically bind TA-MUC1 on tumor cells via its mAb moiety, to IL-15 receptors on immune cells via its IL-15 fusion modules and to FcγRs via its functional Fc-part. In vitro, NK, NKT and CD8+ T cells were activated and proliferated, leading to anti-tumor cytotoxicity and synergism with antibody-dependent cellular cytotoxicity (ADCC)-mediating mAbs. In vivo, GT-00AxIL15 exhibited favorable PK characteristics with a serum half-life of 13 days and specifically accumulated in TA-MUC1+ tumors. In the tumor microenvironment, GT-00AxIL15 induced robust immune activation and expansion and mediated anti-metastatic and anti-tumor effects in syngeneic and xenograft tumor models. These results support the rationale to improve PK and anti-tumor efficacy of IL-15 by increasing local concentrations at the tumor site via conjugation to a TA-MUC1 binding mAb. The tumor-selective expression pattern of TA-MUC1, powerful immune activation and anti-tumor cytotoxicity, long serum half-life and tumor targeting properties, render GT-00AxIL15 a promising candidate for treatment of solid tumors with high medical need, e.g., ovarian, lung and breast cancer.

Multiple myeloma (MM) remains a challenging hematologic malignancy despite advancements in chimeric antigen receptor T-cell (CAR-T) therapy. Current targets of CAR-T cells used in MM immunotherapy have limitations, with a subset of patients experiencing antigen loss resulting in relapse. Therefore, novel targets for enhancing CAR-T cell therapy in MM remain needed. Fc receptor-like 5 (FCRL5) is a protein marker with considerably upregulated expression in MM and has emerged as a promising target for CAR-T cell therapeutic interventions, offering an alternative treatment for MM. To further explore this option, we designed FCRL5-directed CAR-T cells and assessed their cytotoxicity in vitro using a co-culture system and in vivo using MM cell-derived xenograft models, specifically focusing on MM with gain of chromosome 1q21. Given the challenges in CAR-T therapies arising from limited T cell persistence, our approach incorporates interleukin-15 (IL-15), which enhances the functionality of central memory T (TCM) cells, into the design of FCRL5-directed CAR-T cells, to improve cytotoxicity and reduce T-cell dysfunction, thereby promoting greater CAR-T cell survival and efficacy. Both in vitro and xenograft models displayed that FCRL5 CAR-T cells incorporating IL-15 exhibited potent antitumor efficacy, effectively inhibiting the proliferation of MM cells and leading to remarkable tumor suppression. Our results highlight the capacity of FCRL5-specific CAR-T cells with the integration of IL-15 to improve the therapeutic potency, suggesting a potential novel immunotherapeutic strategy for MM treatment., (© 2023. The Author(s).)

Object: To clarify the involvement of clock genes in the production of inflammatory mediators from RA-FLS, we examined the role of Bmal1, one of the master clock genes., Methods: RA-FLSs were stimulated with IL-1β (0, 20 ng/mL), IL-6 (0, 20 ng/mL), IL-17 (0, 20 ng/mL), TNF-α (0, 20 ng/mL) or IFN-γ (0, 20 ng/mL) to examine the expression of Bmal1, MMP-3, CCL2, IL-6, IL-7 and IL-15 by qPCR and immunofluorescence staining. After silencing Bmal1, RA-FLSs were stimulated with IL-1β (0, 20 ng/mL), TNF-α (0, 20 ng/mL) or IFN-γ (0, 20 ng/mL) to examine the expressions of inflammatory mediators; MMP-3, CCL2, IL-6 and IL-15 by qPCR, ELISA and immunofluorescence staining., Results: Bmal1 expressions were increased by IL-1β, TNF-α and IFN-γ stimulations. Under stimulations with TNF-α, IL-1β, and IFN-γ, mRNA and protein expressions of MMP-3, CCL2 and IL-6 were suppressed by siBmal1., Conclusion: Results indicate that Bmal1 contributes the production of MMP-3, CCL2, and IL-6 from RA-FLS, implying Bmal1 is involved in the pathogenesis of RA by regulating the inflammation., Competing Interests: Declaration of competing interest There is no conflict of interests regarding the publication of this article., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Intestinal intraepithelial lymphocytes (IELs) exhibit prompt innate-like responses to microenvironmental cues and require strict control of effector functions. Here we showed that Aiolos, an Ikaros zinc-finger family member encoded by Ikzf3, acted as a regulator of IEL activation. Ikzf3 -/- CD8αα + IELs had elevated expression of NK receptors, cytotoxic enzymes, cytokines and chemokines. Single-cell RNA sequencing of Ikzf3 -/- and Ikzf3 +/+ IELs showed an amplified effector machinery in Ikzf3 -/- CD8αα + IELs compared to Ikzf3 +/+ counterparts. Ikzf3 -/- CD8αα + IELs had increased responsiveness to interleukin-15, which explained a substantial part, but not all, of the observed phenotypes. Aiolos binding sites were close to those for the transcription factors STAT5 and RUNX, which promote interleukin-15 signaling and cytolytic programs, and Ikzf3 deficiency partially increased chromatin accessibility and histone acetylation in these regions. Ikzf3 deficiency in mice enhanced susceptibility to colitis, underscoring the relevance of Aiolos in regulating the effector function in IELs., (© 2023. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Oncolytic virotherapy is a promising therapeutic approach for glioblastoma (GBM) treatment, although the outcomes are partially satisfactory. Hence, more effective strategies are needed urgently to modify therapeutic viruses to enhance their efficiency and safety in killing tumor cells and improve the survival rate of GBM patients. This study generated a new-generation oncolytic adenovirus Ad5 KT-E1A-IL-15 (TS-2021) and evaluated its antitumor efficacy. Ex vivo analyses revealed Ki67 and TGF-β2 co-localized in GBM cells. In addition, TS-2021 selectively replicated in GBM cells, which was dependent on the expression of Ki67 and TGF-β2. The immunocompetent mice model of GBM demonstrated the in vivo efficacy of TS-2021 by inhibiting tumor growth and improving survival proficiently. Notably, TS-2021 effectively reduced MMP3 expression by inactivating the MKK4/JNK pathway, thereby reducing tumor invasiveness. Altogether, the findings of the present study highlight that TS-2021 can effectively target GBM cells expressing high levels of Ki67 and TGF-β2, exerting potent antitumor effects. Additionally, it can improve efficacy and suppress tumor invasiveness by inhibiting the MKK4/JNK/MMP3 pathway. Thus our study demonstrates the efficiency of the novel TS-2021 in the mouse model and provides a potential therapeutic option for patients with GBM., (© 2023 Wiley Periodicals LLC.)

Skeletal muscle dysfunction (SMD) is the most significant extrapulmonary complication and an independent prognostic indicator in patients with chronic obstructive pulmonary disease (COPD). Myokines, such as interleukin (IL)-6, IL-15, myostatin, irisin, and insulin-like growth factor (IGF)-1, play important roles in skeletal muscle mitochondrial function, protein synthesis and breakdown balance, and regeneration of skeletal muscles in COPD. As the main component of pulmonary rehabilitation, exercise can improve muscle strength, muscle endurance, and exercise capacity in patients with COPD, as well as improve the prognosis of SMD and COPD by regulating the expression levels of myokines. The mechanisms by which exercise regulates myokine levels are related to microRNAs. IGF-1 expression is upregulated by decreasing the expression of miR-1 or miR-29b. Myostatin downregulation and irisin upregulation are associated with increased miR-27a expression and decreased miR-696 expression, respectively. These findings suggest that myokines are potential targets for the prevention and treatment of SMD in COPD. A comprehensive analysis of the role and regulatory mechanisms of myokines can facilitate the development of new exercise-based therapeutic approaches for patients with COPD.

Problem: Whether the abnormal development of uterine natural killer (uNK) cells contributes to women with recurrent implantation failure (RIF) remains unclear., Method of Study: We characterized the development of uNK cells and peripheral blood NK cells (pbNK) in the mid-luteal phase in women with RIF (n = 31) and controls (n = 14) by flow cytometry. Endometrial IL-15 mRNA expression was studied by quantitative reverse transcription-PCR. The GSE58144 dataset was used to validate the correlation results., Results: We found decreased proportions of stage 4 CD56+CD16-CD94+ uNK cells (median: 9.56% vs. 17.78%, P .014) and increased proportions of stage 6 CD56+CD16+CD57+ uNK cells (median: 1.54% vs. 0.74%, P = .020) in the mid-luteal endometrium of women with RIF compared to fertile women. We also found that there was no quantitative correlation between uNK cells and the corresponding pbNK cell subpopulations (P > .05). In addition, IL-15 mRNA levels in the mid-luteal endometrium were positively correlated with the proportion of CD56+ uNK cells (r = .392, P = .008), especially with stage 4 uNK cell populations (r = .408, P = .005)., Conclusions: We showed that the proportion of stage 4 uNK cells decreased in the RIF group compared to controls, and the decrease in stage 4 uNK cells correlated positively with low IL-15 mRNA expression. We suggest that the reduced stage 4 uNK cells in women with RIF are associated with IL-15 deficiency., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Purpose: Although skeletal muscle releases cytokines called myokines during exercise, the kinetics of the acute myokine response to exercise (exercise-induced circulatory myokine level alteration) is unknown in patients with advanced prostate cancer. We measured myokine levels in serum obtained from patients with metastatic castrate-resistant prostate cancer (mCRPC) before and after exercise and assessed the growth-suppressive effect of the serum by applying it to a PCa cell line., Methods: Nine patients with mCRPC (age = 67.8 ± 10.1 years, time since mCRPC diagnosis 36.2 ± 22.5 months) undertook 34 min of a high-intensity interval exercise session on a cycle ergometer. Blood was collected immediately pre, post and 30 min post. Serum levels of secreted protein acidic and rich in cysteine (SPARC), oncostatin M (OSM), interleukin-6 (IL-6), interleukin-15 (IL-15), decorin, irisin, and IGF-1 were determined. Growth of the androgen-independent PCa cell line DU-145 exposed to serum collected at three points was measured., Results: There was a significant elevation of SPARC (19.9%, P = 0.048), OSM (11.5%, P = 0.001), IL-6 (10.2%, P = 0.02) and IL-15 (7.8%, P = 0.023) in serum collected immediately after exercise compared to baseline, returning to baseline after 30 min rest. A significant reduction in DU-145 Cell growth and the Cell Index area under the curve at 72 h incubation was observed with the presence of serum obtained immediately post-exercise (Cell Index at 72 h: 16.9%, P < 0.001; area under the curve: 15.2%, P < 0.001) and with the presence of serum obtained 30 min post-exercise compared to baseline (Cell Index at 72 h: 6.5%; area under the curve: 8.8%, P < 0.001)., Conclusion: This study provides preliminary evidence for an acute exercise-induced myokine response and tumour growth suppression in serum after a bout of high-intensity interval exercise in patients with advanced PCa., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

The efficacy of CAR-T cell therapy has been hindered by several factors that are intrinsic to the tumor microenvironment. Many strategies are being employed to overcome these barriers and improve immunotherapies efficacy. Interleukin (IL)- 4 is a cytokine released by tumor cells inside the tumor microenvironment and it can oppose T cell effector functions via engagement with the IL-4 receptor on the surface of T cells. To overcome IL-4-mediated immunosuppressive signals, we designed a novel inverted cytokine receptor (ICR). Our novel CAR construct (4/15NKG2D-CAR), consisted of an NKG2D-based chimeric antigen receptor, co-expressing IL-4R as an extracellular domain and IL-15R as a transmembrane and intracellular domain. In this way, IL-4R inhibitory signals were converted into IL-15R activation signals downstream. This strategy increased the efficacy of NKG2D-CAR-T cells in the pancreatic tumor microenvironment in vitro and in vivo. 4/15NKG2D-CAR-T cells exhibited increased activation, degranulation, cytokine release, and cytotoxic ability of NKG2D-CAR-T cells against IL-4 + pancreatic cell lines. Furthermore, 4/15NKG2D-CAR-T cells exhibited more expansion, less exhaustion, and an increased percentage of less differentiated T cell phenotypes in vitro when compared with NKG2D-CAR-T cells. That is why IL-4R/IL-15R-modified CAR-T cells eradicated more tumors in vivo and outperformed NKG2D-CAR-T cells. Thus, we report here a novel NKG2D-CAR-T cells that could overcome IL-4-mediated immunosuppression in solid tumors., Competing Interests: Declaration of Competing Interest The authors declare that there are no conflicts of interest., (Copyright © 2023 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Background: Limited research has been conducted on the post-intervention inflammatory status in sarcopenic patients, despite previous studies revealing elevated pro-inflammatory markers. This study aimed to investigate the potential elevation of specific pro-inflammatory cytokines in sarcopenic patients and evaluate the effects of exercise and nutritional support interventions on these cytokine levels., Methods: In this post-hoc analysis of a randomized controlled trial (RCT), 57 individuals with sarcopenia from the RCT and 57 non-sarcopenic participants from the same geriatric community cohort that did not participate in the RCT were enrolled. Grip strength and body composition measurements were recorded. Tumor necrotizing factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-15 levels were assessed at baseline for both groups and after a 12-week intervention consisting of resistive exercise and supplementation with branched-chain amino acids, calcium, and vitamin D3 in the patients with sarcopenia., Results: The sarcopenic group demonstrated significantly lower body weight, body mass index, grip strength, and skeletal muscle mass index. Moreover, sarcopenic patients exhibited higher levels of TNF-α ( p =0.007), IL-1β ( p <0.001), and IL-6 ( p <0.001), while no significant difference was observed in IL-15 ( p =0.345) between participants with and those without sarcopenia. Following the intervention, the sarcopenic group experienced significant improvements in grip strength and skeletal muscle mass index with a notable reduction in TNF-α ( p =0.003), IL-1β ( p =0.012) and IL-6 ( p =0.001) levels., Conclusions: Sarcopenic patients exhibit elevated levels of TNF-α, IL-1β, and IL-6, which declined after nutrition support and exercise interventions. However, further research is necessary to evaluate the long-term impact of these interventions on cytokine levels.

NK effector functions can be triggered by inflammatory cytokines and engagement of activating receptors. NK cell production of IFN-γ, an important immunoregulatory cytokine, exhibits activation-specific IFN-γ regulation. Resting murine NK cells exhibit activation-specific metabolic requirements for IFN-γ production, which are reversed for activating receptor-mediated stimulation following IL-15 priming. Although both cytokine and activating receptor stimulation leads to similar IFN-γ protein production, only cytokine stimulation upregulates Ifng transcript, suggesting that protein production is translationally regulated after receptor stimulation. Based on these differences in IFN-γ regulation, we hypothesized that ex vivo IL-15 priming of murine NK cells allows a switch to IFN-γ transcription upon activating receptor engagement. Transcriptional analysis of primed NK cells compared with naive cells or cells cultured with low-dose IL-15 demonstrated that primed cells strongly upregulated Ifng transcript following activating receptor stimulation. This was not due to chromatin accessibility changes in the Ifng locus or changes in ITAM signaling, but was associated with a distinct transcriptional signature induced by ITAM stimulation of primed compared with naive NK cells. Transcriptional analyses identified a common signature of c-Myc (Myc) targets associated with Ifng transcription. Although Myc marked NK cells capable of Ifng transcription, Myc itself was not required for Ifng transcription using a genetic model of Myc deletion. This work highlights altered regulatory networks in IL-15-primed cells, resulting in distinct gene expression patterns and IFN-γ regulation in response to activating receptor stimulation., (Copyright © 2023 by The American Association of Immunologists, Inc.)

Background: Combination antiretroviral therapy (cART) has dramatically extended the life expectancy of people living with HIV-1 and improved their quality of life. There is nevertheless no cure for HIV-1 infection since HIV-1 persists in viral reservoirs of latently infected CD4 + T cells. cART does not eradicate HIV-1 reservoirs or restore cytotoxic natural killer (NK) cells which are dramatically reduced by HIV-1 infection, and express the checkpoint inhibitors NKG2A or KIR2DL upregulated after HIV-1 infection. Cytotoxic NK cells expressing the homing receptor CXCR5 were recently described as key subsets controlling viral replication., Methods: We designed and evaluated the potency of "Natural killer activating Multimeric immunotherapeutic compleXes", called as NaMiX, combining multimers of the IL-15/IL-15Rα complex with an anti-NKG2A or an anti-KIR single-chain fragment variable (scFv) to kill HIV-1 infected CD4 + T cells. The oligomerization domain of the C4 binding protein was used to associate the IL-15/IL-15Rα complex to the scFv of each checkpoint inhibitor as well as to multimerize each entity into a heptamer (α form) or a dimer (β form). Each α or β form was compared in different in vitro models using one-way ANOVA and post-hoc Tukey's tests before evaluation in humanized NSG tg-huIL-15 mice having functional NK cells., Results: All NaMiX significantly enhanced the cytolytic activity of NK and CD8 + T cells against Raji tumour cells and HIV-1 + ACH-2 cells by increasing degranulation, release of granzyme B, perforin and IFN-γ. Targeting NKG2A had a stronger effect than targeting KIR2DL due to higher expression of NKG2A on NK cells. In viral inhibition assays, NaMiX initially increased viral replication of CD4 + T cells which was subsequently inhibited by cytotoxic NK cells. Importantly, anti-NKG2A NaMiX enhanced activation, cytotoxicity, IFN-γ production and CXCR5 expression of NK cells from HIV-1 positive individuals. In humanized NSG tg-huIL-15 mice, we confirmed enhanced activation, degranulation, cytotoxicity of NK cells, and killing of HIV-1 infected cells from mice injected with the anti-NKG2A.α NaMiX, as compared to control mice, as well as decreased total HIV-1 DNA in the lung., Conclusions: NK cell-mediated killing of HIV-1 infected cells by NaMiX represents a promising approach to support HIV-1 cure strategies., (© 2023. The Author(s).)

Objective: Numerous immune cell types, such as B and T lymphocytes, natural killer cells (NK), and NKT cells, are related to the pathogenesis of diseases in systemic lupus erythematosus (SLE). Our goal in this investigation is to examine the phenotype of NK cells and NKT cells alterations in individuals with SLE., Methods: Typically, 50 SLE patients and 24 age-matched healthy people had their PBMCs obtained. Employing flow cytometry, the phenotype of NK and NKT cells and immunoglobulin-like transcript 2 (ILT2) expressions were identified. ELISA was utilized to evaluate the amounts of interleukin-15 (IL-15) and sHLA-G in the serum., Results: The frequencies of the circulating NK and NKT cells in individuals with SLE were decreased compared to healthy controls. Furthermore, ILT2 expression was significantly increased in NKT cells, but showed no obvious change in NK cells. Clinical severity and active nephritis were substantially associated with ILT2 + NKT cell frequencies. The correlation study showed that the upregulation of ILT2 expression was related to sHLA-G in plasma but not to IL-15., Conclusions: ILT2 + NKT cells have a vital function in the immune abnormalities of SLE, which can also supply a viable goal for therapeutic intervention. Key Points •ILT2 expression was significantly increased in NKT cells in SLE patients. •ILT2+ NKT cell frequencies were associated with clinical severity which may be used as an indicator for evaluating disease activity in patients with SLE., (© 2023. The Author(s), under exclusive licence to International League of Associations for Rheumatology (ILAR).)

Natural killer (NK) cells are frequently expanded for the clinic using irradiated, engineered K562 feeder cells expressing a core transgene set of membrane-bound (mb) IL15 and/or mbIL21 together with 41BBL. Prior comparisons of mbIL15 to mbIL21 for NK expansion lack comparisons of key attributes of the resulting NK cells, including their high-dimensional phenotype, polyfunctionality, the breadth and potency of cytotoxicity, cellular metabolism, and activity in xenograft tumor models. Moreover, despite multiple rounds of K562 stimulation, studies of sequential use of mbIL15- and mbIL21-based feeder cells are absent. We addressed these gaps and found that using mbIL15- versus mbIL21-based feeder cells drove distinct phenotypic and functional profiles. Feeder cells expressing mbIL15 alone drove superior functionality by nearly all measures, whereas those expressing mbIL21 alone drove superior yield. In combination, most attributes resembled those imparted by mbIL21, whereas in sequence, NK yield approximated that imparted by the first cytokine, and the phenotype, transcriptome, and function resembled that driven by the second cytokine, highlighting the plasticity of NK cell differentiation. The sequence mbIL21 followed by mbIL15 was advantageous in achieving significant yields of highly functional NK cells that demonstrated equivalent in vivo activity to those expanded by mbIL15 alone in two of three xenograft models. Our findings define the impact of mbIL15 versus mbIL21 during NK expansion and reveal a previously underappreciated tradeoff between NK yield and function for which sequential use of mbIL21-based followed by mbIL15-based feeder cells may be the optimal approach in many settings., (©2023 The Authors; Published by the American Association for Cancer Research.)

The study aims to explore the active molecules of traditional Chinese medicine that specifically bind to interleukin-15 receptor α (IL-15Rα) using molecular docking and surface plasmon resonance (SPR) technology. AutoDock molecular docking software was used to perform simulated docking of more than 3 000 compounds from 48 traditional Chinese medicines at IL-15Rα and screen the specific binding compounds. Then Biocore T200 biomolecular interaction analysis system of SPR was used to confirm the binding specificity of the selected target compounds. Finally, the biological effects of the target compounds on IL-15Rα were verified by cell biological experiments. The results showed that neoprzewaquinone A (Neo) possessed the highest specific binding affinity among the active molecules from traditional Chinese medicine, and the dissociation constant (K D ) value was (0.62 ± 0.20) µmol/L. The results of cell experiment showed that Neo significantly inhibited the proliferation of Mo7e cells induced by IL-15, and the IC 50 was 1.075 µmol/L, approximately 1/120 of the IC 50 of Cefazolin (IL-15 specific antagonist). These results suggest that Neo is a specific inhibitor of IL-15Rα and may be a potential active drug for the treatment of diseases related to the dysfunction of the IL-15Rα signaling.

The majority of patients with acute myeloid leukemia (AML) succumb to the disease or its complications, especially among older patients. Natural killer (NK) cells have been shown to have antileukemic activity in patients with AML; however, to our knowledge, primary NK cells armed with a chimeric antigen receptor (CAR) targeting antigens associated with AML as an "off-the-shelf" product for disease control have not been explored. We developed frozen, off-the-shelf allogeneic human NK cells engineered with a CAR recognizing FLT3 and secreting soluble interleukin-15 (IL-15) (FLT3 CAR&#95;sIL-15 NK) to improve in vivo NK cell persistence and T-cell activation. FLT3 CAR&#95;sIL-15 NK cells had higher cytotoxicity and interferon gamma secretion against FLT3+ AML cell lines when compared with activated NK cells lacking an FLT3 CAR or soluble IL-15. Frozen and thawed allogeneic FLT3 CAR&#95;sIL-15 NK cells prolonged survival of both the MOLM-13 AML model as well as an orthotopic patient-derived xenograft AML model when compared with control NK cells. FLT3 CAR&#95;sIL-15 NK cells showed no cytotoxicity against healthy blood mononuclear cells or hematopoietic stem cells. Collectively, our data suggest that FLT3 is an AML-associated antigen that can be targeted by frozen, allogeneic, off-the-shelf FLT3 CAR&#95;sIL-15 NK cells that may provide a novel approach for the treatment of AML., (© 2023 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Introduction: Natural killer 92 (NK-92) cells are an attractive therapeutic approach as alternative chimeric antigen receptor (CAR) carriers, different from T cells, once they can be used in the allogeneic setting. The modest in vivo outcomes observed with NK-92 cells continue to present hurdles in successfully translating NK-92 cell therapies into clinical applications. Adoptive transfer of CAR-NK-92 cells holds out the promise of therapeutic benefit at a lower rate of adverse events due to the absence of GvHD and cytokine release syndrome. However, it has not achieved breakthrough clinical results yet, and further improvement of CAR-NK-92 cells is necessary., Methods: In this study, we conducted a comparative analysis between CD19-targeted CAR (CAR.19) co-expressing IL-15 (CAR.19-IL15) with IL-15/IL-15Rα (CAR.19-IL15/IL15Rα) to promote NK cell proliferation, activation, and cytotoxic activity against B-cell leukemia. CAR constructs were cloned into lentiviral vector and transduced into NK-92 cell line. Potency of CAR-NK cells were assessed against CD19-expressing cell lines NALM-6 or Raji in vitro and in vivo in a murine model. Tumor burden was measured by bioluminescence., Results: We demonstrated that a fourth- generation CD19-targeted CAR (CAR.19) co-expressing IL-15 linked to its receptor IL-15/IL-15Rα (CAR.19-IL-15/IL-15Rα) significantly enhanced NK-92 cell proliferation, proinflammatory cytokine secretion, and cytotoxic activity against B-cell cancer cell lines in vitro and in a xenograft mouse model., Conclusion: Together with the results of the systematic analysis of the transcriptome of activated NK-92 CAR variants, this supports the notion that IL-15/IL-15Rα comprising fourth-generation CARs may overcome the limitations of NK-92 cell-based targeted tumor therapies in vivo by providing the necessary growth and activation signals., Competing Interests: VPC, DTC, RNS, RC and JTCA are inventors of the patent PCT/BR2023/050127 owned by their respective institutions. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer AT declared a past co-authorship with the author TT, and declared a shared affiliation with several of the authors JE, PM, TT to the handling editor at the time of the review., (Copyright © 2023 Silvestre, Eitler, de Azevedo, Tirapelle, Fantacini, de Souza, Swiech, Covas, Calado, Montero, Malmegrim, Figueiredo, Tonn and Picanço-Castro.)

The aim of this study was to investigate the functional characteristics and in vitro specific killing effect of EGFRvIII CAR-T cells co-expressing interleukin-15 and chemokine CCL19, in order to optimize the multiple functions of CAR-T cells and improve the therapeutic effect of CAR-T cells targeting EGFRvIII on glioblastoma (GBM). The recombinant lentivirus plasmid was obtained by genetic engineering, transfected into 293T cells to obtain lentivirus and infected T cells to obtain the fourth generation CAR-T cells targeting EGFRvIII (EGFRvIII-IL-15-CCL19 CAR-T). The expression rate of CAR molecules, proliferation, chemotactic ability, in vitro specific killing ability and anti-apoptotic ability of the fourth and second generation CAR-T cells (EGFRvIII CAR-T) were detected by flow cytometry, cell counter, chemotaxis chamber and apoptosis kit. The results showed that compared with EGFRvIII CAR-T cells, EGFRvIII-IL-15-CCL19 CAR-T cells successfully secreted IL-15 and CCL19, and had stronger proliferation, chemotactic ability and anti-apoptosis ability in vitro (all P < 0.05), while there was no significant difference in killing ability in vitro . Therefore, CAR-T cells targeting EGFRvIII and secreting IL-15 and CCL19 are expected to improve the therapeutic effect of glioblastoma and provide an experimental basis for clinical trials.

IL-15 is under clinical investigation toward the goal of curing HIV infection because of its abilities to reverse HIV latency and enhance immune effector function. However, increased potency through combination with other agents may be needed. 3-Hydroxy-1,2,3-benzotriazin-4(3H)-one (HODHBt) enhances IL-15-mediated latency reversal and NK cell function by increasing STAT5 activation. We hypothesized that HODHBt would also synergize with IL-15, via STAT5, to directly enhance HIV-specific cytotoxic T cell responses. We showed that ex vivo IL-15 + HODHBt treatment markedly enhanced HIV-specific granzyme B-releasing T cell responses in PBMCs from antiretroviral therapy-suppressed (ART-suppressed) donors. We also observed upregulation of antigen processing and presentation in CD4+ T cells and increased surface MHC-I. In ex vivo PBMCs, IL-15 + HODHBt was sufficient to reduce intact proviruses in 1 of 3 ART-suppressed donors. Our findings reveal the potential for second-generation IL-15 studies incorporating HODHBt-like therapeutics. Iterative studies layering on additional latency reversal or other agents are needed to achieve consistent ex vivo reservoir reductions.

Regular exercise reduces the risk of malignancy and decreases the recurrence of cancer. However, the mechanisms behind this protection remain to be elucidated. Natural killer (NK) cells are lymphocytes of the innate immune system, which play essential roles in immune defense and effectively prevent cancer metastasis. Physical exercise can increase the activity of NK cells. Interleukin-15 (IL-15) is the best-studied cytokine activator of NK cells, and it was shown to have many positive functional effects on NK cells to improve antitumor responses. The aim of this study was to clarify the possible important mechanisms behind endurance exercise-induced changes in NK cell function, which may be highly correlated with IL-15. An animal model was used to study IL-15 expression level, tumor volume, cancer cell apoptosis, and NK cell infiltration after treadmill exercise. Although IL-15 was highly expressed in skeletal muscle, treadmill exercise further elevated IL-15 levels in plasma and muscle (P<0.05). In addition, tumor weight and volume of tumor-bearing mice were decreased (P<0.05), and liver tumor cell apoptosis was increased after 12 weeks of treadmill exercise (P<0.05). NK cell infiltration was upregulated in tumors from treadmill exercise mice, and the level of interferon-gamma (IFN-γ) and IL-15 were higher than in sedentary mice (P<0.05). The study indicated that regular endurance training can reduce cancer risk, which was related to increased IL-15 expression, activation of the immune killing effect of NK cells, and promotion of tumor cell apoptosis, which can ultimately control tumor growth.

Obesity, in which the functional importance of small nucleolar RNAs (snoRNAs) remains elusive, correlates with risk for many cancer types. Here, we identify that the serum copies of adipocyte-expressed SNORD46 correlate with body mass index (BMI), and serum SNORD46 antagonizes interleukin-15 (IL-15) signaling. Mechanically, SNORD46 binds IL-15 via G11, and G11A (a mutation that significantly enhances binding affinity) knockin drives obesity in mice. Functionally, SNORD46 blocks IL-15-induced, FER kinase-dependent phosphorylation of platelet glycoprotein 4 (CD36) and monoglyceride lipase (MGLL) in adipocytes, leading to inhibited lipolysis and browning. In natural killer (NK) cells, SNORD46 suppresses the IL-15-dependent autophagy, leading to reduced viability of obese NK. SNORD46 power inhibitors exhibit anti-obesity effects, concurring with improved viability of obese NK and anti-tumor immunity of CAR-NK cell therapy. Hence, our findings demonstrate the functional importance of snoRNAs in obesity and the utility of snoRNA power inhibitors for antagonizing obesity-associated immune resistance., Competing Interests: Declaration of interests M.A.C. reports grants and personal fees from ImmunoGenesis, Inc. and personal fees from Alligator Bioscience, Inc.; ImmunOS, Inc.; Oncoresponse, Inc.; Nurix, Inc.; Aptevo, Inc.; Kineta, Inc.; Xencor, Inc.; Agenus, Inc.; Adagene, Inc.; and Astrazeneca, Inc. outside the submitted work. K.R. and the University of Texas MD Anderson Cancer Center have an institutional financial conflict of interest with Takeda Pharmaceutical and Affimed GmbH. K.R. participates on the Scientific Advisory Board for GemoAb, AvengeBio, Virogin Biotech, GSK, Caribou Biosciences, Navan Technologies, and Bayer. B.G. is an inventor on patent applications involving targeting ferroptosis in cancer therapy and reports personal fees from Guidepoint Global, Cambridge Solutions, and NGM Bio., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

The treatment of patients with metastatic melanoma with immune checkpoint inhibitors (ICI) leads to impressive response rates but primary and secondary resistance to ICI reduces progression-free survival. Novel strategies that interfere with resistance mechanisms are key to further improve patient outcome during ICI therapy. P53 is often inactivated by mouse-double-minute-2 (MDM2), which may decrease immunogenicity of melanoma cells. We analyzed primary patient-derived melanoma cell lines, performed bulk sequencing analysis of patient-derived melanoma samples, and used melanoma mouse models to investigate the role of MDM2-inhibition for enhanced ICI therapy. We found increased expression of IL15 and MHC-II in murine melanoma cells upon p53 induction by MDM2-inhibition. MDM2-inhibitor induced MHC-II and IL15-production, which was p53 dependent as Tp53 knockdown blocked the effect. Lack of IL15-receptor in hematopoietic cells or IL15 neutralization reduced the MDM2-inhibition/p53-induction-mediated antitumor immunity. P53 induction by MDM2-inhibition caused anti-melanoma immune memory as T cells isolated from MDM2-inhibitor-treated melanoma-bearing mice exhibited anti-melanoma activity in secondary melanoma-bearing mice. In patient-derived melanoma cells p53 induction by MDM2-inhibition increased IL15 and MHC-II. IL15 and CIITA expressions were associated with a more favorable prognosis in patients bearing WT but not TP53-mutated melanoma., Implications: MDM2-inhibition represents a novel strategy to enhance IL15 and MHC-II-production, which disrupts the immunosuppressive tumor microenvironment. On the basis of our findings, a clinical trial combining MDM2-inhibition with anti-PD-1 immunotherapy for metastatic melanoma is planned., (©2023 American Association for Cancer Research.)

Chimeric antigen receptor (CAR) engineering of natural killer (NK) cells is promising, with early-phase clinical studies showing encouraging responses. However, the transcriptional signatures that control the fate of CAR-NK cells after infusion and factors that influence tumor control remain poorly understood. We performed single-cell RNA sequencing and mass cytometry to study the heterogeneity of CAR-NK cells and their in vivo evolution after adoptive transfer, from the phase of tumor control to relapse. Using a preclinical model of noncurative lymphoma and samples from a responder and a nonresponder patient treated with CAR19/IL-15 NK cells, we observed the emergence of NK cell clusters with distinct patterns of activation, function, and metabolic signature associated with different phases of in vivo evolution and tumor control. Interaction with the highly metabolically active tumor resulted in loss of metabolic fitness in NK cells that could be partly overcome by incorporation of IL-15 in the CAR construct.

Allogeneic natural killer (NK) cell adoptive transfer has shown the potential to induce remissions in relapsed or refractory leukemias and lymphomas, but strategies to enhance NK cell survival and function are needed to improve clinical efficacy. Here, we demonstrated that NK cells cultured ex vivo with interleukin-15 (IL-15) and nicotinamide (NAM) exhibited stable induction of l-selectin (CD62L), a lymphocyte adhesion molecule important for lymph node homing. High frequencies of CD62L were associated with elevated transcription factor forkhead box O1 (FOXO1), and NAM promoted the stability of FOXO1 by preventing proteasomal degradation. NK cells cultured with NAM exhibited metabolic changes associated with elevated glucose flux and protection against oxidative stress. NK cells incubated with NAM also displayed enhanced cytotoxicity and inflammatory cytokine production and preferentially persisted in xenogeneic adoptive transfer experiments. We also conducted a first-in-human phase 1 clinical trial testing adoptive transfer of NK cells expanded ex vivo with IL-15 and NAM (GDA-201) combined with monoclonal antibodies in patients with relapsed or refractory non-Hodgkin lymphoma (NHL) and multiple myeloma (MM) (NCT03019666). Cellular therapy with GDA-201 and rituximab was well tolerated and yielded an overall response rate of 74% in 19 patients with advanced NHL. Thirteen patients had a complete response, and 1 patient had a partial response. GDA-201 cells were detected for up to 14 days in blood, bone marrow, and tumor tissues and maintained a favorable metabolic profile. The safety and efficacy of GDA-201 in this study support further development as a cancer therapy.

Lung cancer is the most diagnosed malignant cancer and the leading cause of cancer-related deaths worldwide, with advanced stage and metastasis being a major issue. The mechanism leading to metastasis is not yet understood. Here, we found that KRT16 is upregulated in metastatic lung cancer tissues and correlated with poor overall survival. Knockdown of KRT16 inhibits metastasis of lung cancer both in vitro and in vivo. Mechanistically, KRT16 interacts with vimentin, and depletion of KRT16 leads to downregulation of vimentin. KRT16 acquired its oncogenic ability by stabilizing vimentin, and vimentin is required for KRT16-driven metastasis. FBXO21 mediates the polyubiquitination and degradation of KRT16, and vimentin inhibits KRT16 ubiquitination and degradation by impairing its interaction with FBXO21. Significantly, IL-15 inhibits metastasis of lung cancer in a mouse model through upregulation of FBXO21, and the level of IL-15 in circulating serum was significantly higher in nonmetastatic lung cancer patients than in metastatic patients. Our findings indicate that targeting the FBXO21/KRT16/vimentin axis may benefit lung cancer patients with metastasis., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023. Published by Elsevier Ltd.)

XmAb24306 is a lymphoproliferative interleukin (IL)-15/IL-15 receptor α (IL-15Rα) Fc-fusion protein currently under clinical investigation as an immunotherapeutic agent for cancer treatment. XmAb24306 contains mutations in IL-15 that attenuate its affinity to the heterodimeric IL-15 receptor βγ (IL-15R). We observe substantially prolonged pharmacokinetics (PK) (half-life ∼ 2.5 to 4.5 days) in single- and repeat-dose cynomolgus monkey (cyno) studies compared to wild-type IL-15 (half-life ∼ 1 hour), leading to increased exposure and enhanced and durable expansion of NK cells, CD8+ T cells and CD4-CD8- (double negative [DN]) T cells. Drug clearance varied with dose level and time post-dose, and PK exposure decreased upon repeated dosing, which we attribute to increased target-mediated drug disposition (TMDD) resulting from drug-induced lymphocyte expansion (i.e., pharmacodynamic (PD)-enhanced TMDD). We developed a quantitative systems pharmacology (QSP) model to quantify the complex PKPD behaviors due to the interactions of XmAb24306 with multiple cell types (CD8+, CD4+, DN T cells, and NK cells) in the peripheral blood (PB) and lymphoid tissues. The model, which includes nonspecific drug clearance, binding to and TMDD by IL15R differentially expressed on lymphocyte subsets, and resultant lymphocyte margination/migration out of PB, expansion in lymphoid tissues, and redistribution to the blood, successfully describes the systemic PK and lymphocyte kinetics observed in the cyno studies. Results suggest that after 3 doses of every-two-week (Q2W) doses up to 70 days, the relative contributions of each elimination pathway to XmAb24306 clearance are: DN T cells > NK cells > CD8+ T cells > nonspecific clearance > CD4+ T cells. Modeling suggests that observed cellular expansion in blood results from the influx of cells expanded by the drug in lymphoid tissues. The model is used to predict lymphoid tissue expansion and to simulate PK-PD for different dose regimens. Thus, the model provides insight into the mechanisms underlying the observed PK-PD behavior of an engineered cytokine and can serve as a framework for the rapid integration and analysis of data that emerges from ongoing clinical studies in cancer patients as single-agent or given in combination., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Myokines discharged from working muscles are intensively researched in view of rising importance of preventive and secondary preventive effects of the autocrine, paracrine and endocrine functions., Objectives: Recording of the current state of knowledge on the paracrine and endocrine effects of myokines and evaluation of training measures to optimize myokine concentration., Method: A selective database-driven literature search was carried out on myostatin, interleukin-6 (IL-6), interleukin-15 (IL-15), irisin, cathepsin B, brain-derived neurotrophic factor (BDNF), meteorin-like and kynurenine for the period 2011 until June 2021. The paracrine and endocrine effects of the myokines are analyzed. Their release after acute physical stress and training is described., Results: IL-6 and IL-15 act in lipid metabolism and carbohydrate metabolism, IL-6 also in the brain and immune system. Irisin produces a conversion of white to brown adipose tissue ("browning"), so does meteorin-like. Cathepsin B has a central effect. Kynurenine acts indirectly via kynurenic acid in the brain. The secretion of myokines depends on the intensity of physical stress and is modified by training. Prevention of vascular and neurologic diseases, cognitive enhancement and increased immunological function can be reached by setting free myokines during physical activity. Therapeutical use by technologically modified myokines is proposed in metabolic and neurological diseases, immobilization and sarcopenia., Conclusions: The current research situation on myokines gives reason to recommend regular muscular activity in addition to the previously evidence-based benefits of sport in order to achieve preventive and therapeutic effects., (© 2023. Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Group 1 innate lymphoid cells (G1-ILCs), including circulating natural killer (NK) cells and tissue-resident type 1 ILCs (ILC1s), are innate immune sentinels critical for responses against infection and cancer. In contrast to relatively uniform NK cells through the body, diverse ILC1 subsets have been characterized across and within tissues in mice, but their developmental and functional heterogeneity remain unsolved. Here, using multimodal in vivo approaches including fate-mapping and targeting of the interleukin 15 (IL-15)-producing microenvironment, we demonstrate that liver parenchymal niches support the development of a cytotoxic ILC1 subset lacking IL-7 receptor (7 R - ILC1s). During ontogeny, fetal liver (FL) G1-ILCs arise perivascularly and then differentiate into 7 R - ILC1s within sinusoids. Hepatocyte-derived IL-15 supports parenchymal development of FL G1-ILCs to maintain adult pool of 7 R - ILC1s. IL-7R + (7R + ) ILC1s in the liver, candidate precursors for 7 R - ILC1s, are not essential for 7 R - ILC1 development in physiological conditions. Functionally, 7 R - ILC1s exhibit killing activity at steady state through granzyme B expression, which is underpinned by constitutive mTOR activity, unlike NK cells with exogenous stimulation-dependent cytotoxicity. Our study reveals the unique ontogeny and functions of liver-specific ILC1s, providing a detailed interpretation of ILC1 heterogeneity., Competing Interests: TA, SA, GC, AS, TN, HM, SK, KO, JD, MM, AS, HO, KI No competing interests declared, (© 2023, Asahi et al.)

Background: Melanoma is a lethal skin cancer, and the risk of developing it is increased by exposure to ultraviolet (UV) radiation. The production of cytokines such as interleukin-15 (IL-15), induced by the exposure of skin cells to UV rays, could also promote melanoma development. The aim of this study is to investigate the possible role of Interleukin-15/Interleukin-15 Receptor α (IL-15/IL-15Rα) complexes in melanoma development., Methods: The expression of IL-15/IL-15Rα complexes by melanoma cells was evaluated both ex vivo and in vitro by tissue microarray, PCR, and flow cytometry. The presence of the soluble complex (sIL-15/IL-15Rα) in the plasma of metastatic melanoma patients was detected using an ELISA assay. Subsequently, we investigated the impact of natural killer (NK) cell activation after rIL-2 starvation followed by exposure to the sIL-15/IL-15Rα complex. Finally, by analyzing public datasets, we studied the correlation between IL-15 and IL-15Rα expressions and melanoma stage, NK and T-cell markers, and overall survival (OS)., Results: Analysis of a melanoma tissue microarray shows a significant increase in the number of IL-15 + tumor cells from the benign nevi to metastatic melanoma stages. Metastatic melanoma cell lines express a phorbol-12-myristate-13-acetate (PMA)-cleavable membrane-bound IL-15 (mbIL-15), whereas cultures from primary melanomas express a PMA-resistant isoform. Further analysis revealed that 26% of metastatic patients present with consistently high plasmatic levels of sIL-15/IL-15Rα. When the recombinant soluble human IL-15/IL-15Rα complex is added to briefly starved rIL-2-expanded NK cells, these cells exhibit strongly reduced proliferation and levels of cytotoxic activity against K-562 and NALM-18 target cells. The analysis of public gene expression datasets revealed that high IL-15 and IL-15Rα intra-tumoral production correlates with the high levels of expression of CD5 + and NKp46 + (T and NK markers) and significantly correlates with a better OS in stages II and III, but not in stage IV., Conclusions: Membrane-bound and secreted IL-15/IL-15Rα complexes are continuously present during progression in melanoma. It is notable that, although IL-15/IL-15Rα initially promoted the production of cytotoxic T and NK cells, at stage IV promotion of the development of anergic and dysfunctional cytotoxic NK cells was observed. In a subgroup of melanoma metastatic patients, the continuous secretion of high amounts of the soluble complex could represent a novel NK cell immune escape mechanism., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Di Matteo, Munari, Fiore, Santopolo, Sampaoli, Pelosi, Chouaib, Tumino, Vacca, Mariotti, Ebert, Machwirth, Haas, Pezzullo, Pietra, Grottoli, Buart, Mortier, Maggi, Moretta, Caruana and Azzarone.)

It has been proposed that cytokines can induce activation of resting T cells in an antigen-independent manner. However, experimental conditions have included the use of fetal serum and nanogram concentrations of added cytokines. To evaluate the effect of cytokines and chemokines generated by activated immune cells on the phenotypic profile of human memory CD4 T cells, the cells were cultured in FBS-free conditions in the presence of IL-15 and 5% of hAB serum and incubated with conditioned medium (CM) obtained from PBMC activated through the TCR using anti-CD3/CD28/CD2 antibodies (TCR-CM) or through TLR4 using bacterial LPS (TLR4-CM). Cytokines and chemokines present in the CMs were evaluated by ProcartaPlex immunoassay. Cell viability, proliferation, and surface markers were determined by flow cytometry on day 2, 5, and 8 of culture. Cell viability was maintained by TLR4-CM plus IL-15 for 8 days but decreased in the presence of the TCR-CM plus IL-15. In combination with IL-15, the TLR4-CM, but not the TCR-CM, maintained the expression of CD3 and CD4 stable. Both conditions stabilized the expression of CD45RO and CCR5. Thus, the TLR4-CM better supported the viability and stability of the memory phenotype. None of the CMs induced proliferation or expression of activation markers; however, they induced an increased expression of CXCR4. This study indicates that resting memory CD4 T cells are not activated by, but may be sensitive to soluble factors produced by antigen or PAMP-stimulated cells, which may contribute to their homeostasis and favor the CXCR4 expression., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

There is a medical need to develop new and effective therapies against triple-negative breast cancer (TNBC). Chimeric antigen receptor (CAR) natural killer (NK) cells are a promising alternative to CAR-T cell therapy for cancer. A search for a suitable target in TNBC identified CD44v6, an adhesion molecule expressed in lymphomas, leukemias and solid tumors that is implicated in tumorigenesis and metastases. We have developed a next-generation CAR targeting CD44v6 that incorporates IL-15 superagonist and checkpoint inhibitor molecules. We could show that CD44v6 CAR-NK cells demonstrated effective cytotoxicity against TNBC in 3D spheroid models. The IL-15 superagonist was specifically released upon recognition of CD44v6 on TNBC and contributed to the cytotoxic attack. PD1 ligands are upregulated in TNBC and contribute to the immunosuppressive tumor microenvironment (TME). Competitive inhibition of PD1 neutralized inhibition by PD1 ligands expressed on TNBC. In total, CD44v6 CAR-NK cells are resistant to TME immunosuppression and offer a new therapeutic option for the treatment of BC, including TNBC.

Background: Metastases are the leading cause of mortality in many cancer types and lungs are one of the most common sites of metastasis alongside the liver, brain, and bones. In melanoma, 85% of late-stage patients harbor lung metastases. A local administration could enhance the targeting of metastases while limiting the systemic cytotoxicity. Therefore, intranasal administration of immunotherapeutic agents seems to be a promising approach to preferentially target lung metastases and decrease their burden on cancer mortality. From observations that certain microorganisms induce an acute infection of the tumor microenvironment leading to a local reactivating immune response, microbial-mediated immunotherapy is a next-generation field of investigation in which immunotherapies are engineered to overcome immune surveillance and escape from microenvironmental cancer defenses., Methods: The goal of our study is to evaluate the potential of the intranasal administration of Neospora caninum in a syngeneic C57BL6 mouse model of B16F10 melanoma lung metastases. It also compares the antitumoral properties of a wild-type N. caninum versus N. caninum secreting human interleukin (IL)-15 fused to the sushi domain of the IL-15 receptor α chain, a potent activator of cellular immune responses., Results: The treatment of murine lung metastases by intranasal administration of an N. caninum engineered to secrete human IL-15 impairs lung metastases from further progression with only 0,08% of lung surface harboring metastases versus 4,4% in wild-type N. caninum treated mice and 36% in untreated mice. The control of tumor development is associated with a strong increase in numbers, within the lung, of natural killer cells, CD8 + T cells and macrophages, up to twofold, fivefold and sixfold, respectively. Analysis of expression levels of CD86 and CD206 on macrophages surface revealed a polarization of these macrophages towards an antitumoral M1 phenotype., Conclusion: Administration of IL-15/IL-15Rα-secreting N. caninum through intranasal administration, a non-invasive route, lend further support to N. caninum -demonstrated clear potential as an effective and safe immunotherapeutic approach for the treatment of metastatic solid cancers, whose existing therapeutic options are scarce. Combination of this armed protozoa with an intranasal route could reinforce the existing therapeutic arsenal against cancer and narrow the spectrum of incurable cancers., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Inflammatory bowel diseases (IBDs) are characterized by abnormal, non-antigen specific chronic inflammation of unknown etiology. Genome-wide association studies show that many IBD genetic susceptibility loci map to immune function genes and compelling evidence indicate that environmental factors play a critical role in IBD pathogenesis. Clinical and experimental evidence implicate the pro-inflammatory cytokine IL-15 in the pathogenesis of IBD. IL-15 and IL-15α expression is increased in the inflamed mucosa of IBD patients. IL-15 contributes to the maintenance of different cell subsets in the intestinal mucosa. However, very few studies have addressed the role of IL-15 in pre-clinical models of colitis. In this study, we use three well-characterized models of experimental colitis to determine the contribution of IL-15 to pathological intestinal inflammation., (© 2022 American Association for Anatomy.)

Background: Type I interferons (IFN-Is), secreted by hematopoietic cells, drive immune surveillance of solid tumors. However, the mechanisms of suppression of IFN-I-driven immune responses in hematopoietic malignancies including B-cell acute lymphoblastic leukemia (B-ALL) are unknown., Methods: Using high-dimensional cytometry, we delineate the defects in IFN-I production and IFN-I-driven immune responses in high-grade primary human and mouse B-ALLs. We develop natural killer (NK) cells as therapies to counter the intrinsic suppression of IFN-I production in B-ALL., Results: We find that high expression of IFN-I signaling genes predicts favorable clinical outcome in patients with B-ALL, underscoring the importance of the IFN-I pathway in this malignancy. We show that human and mouse B-ALL microenvironments harbor an intrinsic defect in paracrine (plasmacytoid dendritic cell) and/or autocrine (B-cell) IFN-I production and IFN-I-driven immune responses. Reduced IFN-I production is sufficient for suppressing the immune system and promoting leukemia development in mice prone to MYC-driven B-ALL. Among anti-leukemia immune subsets, suppression of IFN-I production most markedly lowers the transcription of IL-15 and reduces NK-cell number and effector maturation in B-ALL microenvironments. Adoptive transfer of healthy NK cells significantly prolongs survival of overt ALL-bearing transgenic mice. Administration of IFN-Is to B-ALL-prone mice reduces leukemia progression and increases the frequencies of total NK and NK-cell effectors in circulation. Ex vivo treatment of malignant and non-malignant immune cells in primary mouse B-ALL microenvironments with IFN-Is fully restores proximal IFN-I signaling and partially restores IL-15 production. In B-ALL patients, the suppression of IL-15 is the most severe in difficult-to-treat subtypes with MYC overexpression. MYC overexpression promotes sensitivity of B-ALL to NK cell-mediated killing. To counter the suppressed IFN-I-induced IL-15 production in MYC high human B-ALL, we CRISPRa-engineered a novel human NK-cell line that secretes IL-15. CRISPRa IL-15-secreting human NK cells kill high-grade human B-ALL in vitro and block leukemia progression in vivo more effectively than NK cells that do not produce IL-15., Conclusion: We find that restoration of the intrinsically suppressed IFN-I production in B-ALL underlies the therapeutic efficacy of IL-15-producing NK cells and that such NK cells represent an attractive therapeutic solution for the problem of drugging MYC in high-grade B-ALL., Competing Interests: Competing interests: The work described in this study is covered by pending US and PCT patent applications assigned to City of Hope and/or Stanford University with inventors SS, AK, ATK, CW-C, SJL, CD and HTM. MAC and JY are cofounders of CytoImmune Therapeutics., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

MYC is a pleiotropic transcription factor involved in cancer, cell proliferation, and metabolism. Its regulation and function in NK cells, which are innate cytotoxic lymphocytes important to control viral infections and cancer, remain poorly defined. Here, we show that mice deficient for Myc in NK cells presented a severe reduction in these lymphocytes. Myc was required for NK cell development and expansion in response to the key cytokine IL-15, which induced Myc through transcriptional and posttranslational mechanisms. Mechanistically, Myc ablation in vivo largely impacted NK cells' ribosomagenesis, reducing their translation and expansion capacities. Similar results were obtained by inhibiting MYC in human NK cells. Impairing translation by pharmacological intervention phenocopied the consequences of deleting or blocking MYC in vitro. Notably, mice lacking Myc in NK cells exhibited defective anticancer immunity, which reflected their decreased numbers of mature NK cells exerting suboptimal cytotoxic functions. These results indicate that MYC is a central node in NK cells, connecting IL-15 to translational fitness, expansion, and anticancer immunity., (© 2023 Khameneh et al.)

NK cells represent key players capable of driving antitumor immune responses. However, the potent immunosuppressive activity of the tumor microenvironment (TME) may impair their effector function. Here, we strengthen the importance of metabolic interactions between NK cells and TME and propose metabolic dysfunction as one of the major mechanisms behind NK failure in cancer treatment. In particular, we described that TME has a direct negative impact on NK cell function by disrupting their mitochondrial integrity and function in pediatric and adult patients with primary and metastatic cancer. Our results will help to design new strategies aimed at increasing the NK cell antitumor efficacy by their metabolic reprogramming. In this regard, we reveal an unprecedented role of IL15 in the metabolic reprogramming of NK cells enhancing their antitumor functions. IL15 prevents the inhibitory effect of soluble factors present in TME and restores both the metabolic characteristics and the effector function of NK cells inhibited by exposure to malignant pleural fluid. Thus, we propose here that IL15 may be exploited as a new strategy to metabolically reprogram NK cells with the aim of increasing the efficacy of NK-based immunotherapy in a wide range of currently refractory adult and pediatric solid tumors., (© 2022 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.)

HIV-1 usually utilizes CCR5 as its coreceptor and rarely switches to a CXCR4-tropic virus until the late stage of infection. CCR5+CD4+ T cells are the major virus-producing cells in viremic individuals as well as SIV-infected nonhuman primates. The differentiation of CCR5+CD4+ T cells is associated with the availability of IL-15, which increases during acute HIV-1 infection. Here, we report that CCR5 was expressed by CD4+ T cells exhibiting effector or effector memory phenotypes with high expression levels of the IL-2/IL-15 receptor common β and γ chains. IL-15, but not IL-7, improved the survival of CCR5+CD4+ T cells, drove their expansion, and facilitated HIV-1 infection in vitro and in humanized mice. Our study suggests that IL-15 plays confounding roles in HIV-1 infection, and future studies on the IL-15-based boosting of anti-HIV-1 immunity should carefully examine the potential effects on the expansion of HIV-1 reservoirs in CCR5+CD4+ T cells.

Decidual immunological mediators modulate placental formation, decidualization and fetal development. However, the effect of maternal hyperthyroidism on decidual immunology needs further research. The aim of this study was to evaluate the population of uterine natural killer cells (uNKs) and the expression of immunological mediators in the decidua of female rats throughout pregnancy. Wistar rats were used and hyperthyroidism was induced by daily administration of L-thyroxine (T4) throughout pregnancy. The population of uNK cells in decidua was evaluated by immunostaining Lectin DBA, as well as the expression of interferon γ (INFγ), macrophage migration inhibitory factor (MIF), interleukin 15 (IL-15) and inducible nitric oxide synthase (iNOS) at 7, 10, 12, 14 and 19 days of gestation (DG). Maternal hyperthyroidism reduced the DBA+ uNK cell population in the decidua at 7 (P < 0.05) and 10 (P < 0.01) DGs compared to that in the control group, while it increased in the basal decidua (P < 0.05) and metrial gland (P < 0.0001) at the 12th DG. Hyperthyroidism also increased immunostaining of IL-15 (P < 0.0001), INFγ (P < 0.05), and MIF (P < 0.05) in the 7th DG, and increased immunostaining of IL-15 (P < 0.0001) and MIF (P < 0.01) in th e 10th DG. However, excess thyroxine reduced IL-15 expression in the metrial gland and/or basal decidua in the 12th (P < 0.05), 14th (P < 0.01), and 19th (P < 0.001) DGs, as was also observed for INFγ in the basal decidua (P<0.001) and metrial gland (P < 0.0001) in the 12th DG. Regarding iNOS, an antiinflammatory cytokine, lower expression was observed in the basal decidua of hyperthyroid animals at 7 and 12 DGs (P < 0.05), whereas an increase occurred in the 10th DG (P < 0.05). These data demonstrate that maternal hyperthyroidism in female rats, particularly between 7 and 10 DGs, reduces the population of DBA+ uNKs in the decidua and increases the expression of inflammatory cytokines, suggesting a more proinflammatory environment in early pregnancy caused by this gestational disease., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflicts of interest., (Copyright © 2023 Elsevier GmbH. All rights reserved.)

The gut microbiota regulates chronic inflammation and has been implicated in the pathogenesis of a broad spectrum of disease including autoimmunity and cancer. Microbial short-chain fatty acids (SCFAs) e.g., butyrate have demonstrated immunomodulatory effects and are thought to be key mediators of the host-microbiome interaction. Here, we investigated the effect of butyrate on effector functions of blood derived human NK cells stimulated for 18 h with a combination of IL-12/IL-15, a potent mix of cytokines that drive NK cell activation. We show that butyrate has a strong anti-inflammatory effect on NK cells. NK cells cultured in the presence of butyrate expressed lower levels of activating receptors (TRAIL, NKp30, NKp44) and produced lower levels of cytokines (IFNγ, TNF-α, IL-22, granzyme B, granzyme A, perforin) in response to IL-12/IL-15. Butyrate restricted NK cell function by downregulation of mTORC1 activity, c-Myc mRNA expression and metabolism. Using a shotgun proteomic approach, we confirmed the effect of butyrate on NK cell cytokine signaling and metabolism and identified BRD2, MAT2A and EHD1 as downstream mediators of these effects. This insight into the immunomodulatory activity of butyrate on human NK cell function might help to develop new ways to limit NK cell function during chronic inflammation., (© 2023. The Author(s).)

CD8 virtual memory T (TVM) cells are Ag-naive CD8 T cells that have undergone partial differentiation in response to common γ-chain cytokines, particularly IL-15 and IL-4. TVM cells from young individuals are highly proliferative in response to TCR and cytokine stimulation but, with age, they lose TCR-mediated proliferative capacity and exhibit hallmarks of senescence. Helminth infection can drive an increase in TVM cells, which is associated with improved pathogen clearance during subsequent infectious challenge in young mice. Given the cytokine-dependent profile of TVM cells and their age-associated dysfunction, we traced proliferative and functional changes in TVM cells, compared with true naive CD8 T cells, after helminth infection of young and aged C57BL/6 mice. We show that IL-15 is essential for the helminth-induced increase in TVM cells, which is driven only by proliferation of existing TVM cells, with negligible contribution from true naive cell differentiation. Additionally, TVM cells showed the greatest proliferation in response to helminth infection and IL-15 compared with other CD8 T cells. Furthermore, TVM cells from aged mice did not undergo expansion after helminth infection due to both TVM cell-intrinsic and -extrinsic changes associated with aging., (Copyright © 2023 by The American Association of Immunologists, Inc.)

In silico strategies offer a reliable, fast, and inexpensive, way compared to the clumsy in vitro approaches to boost understanding of the effect of amino acid substitution on the structure and consequently the associated function of proteins. In the present work, we report an atomistic-based, reliable in silico structural and energetic framework of the interactions between the receptor-binding domain of the Interleukin-15 (IL-15) protein and its receptor Interleukin-15α (IL-15α), consequently, providing qualitative and quantitative details of the key molecular determinants in ligand/receptor recognition. Molecular dynamics simulations were used to investigate the dynamic behavior of the specific binding between IL-15 and IL-15α followed by estimation of the free energies via molecular mechanics/generalized Born surface area (MM/GBSA). In particular, residues Y26, E46, E53, and E89 of the IL-15 protein receptor-binding domain are identified as main hot spots, shaping and governing the stability of the assembly. These results can be used for the development of neutralizing antibodies and the effective structure-based design of protein-protein interaction inhibitors against the so-called orphan disease, vitiligo.

Multiple myeloma (MM) is characterized by an immunosuppressive microenvironment that enables tumor development. One of the mechanisms of immune evasion used by MM cells is the inhibition of natural killer (NK) cell effector functions; thus, the restoration of NK cell antitumor activity represents a key goal to increase tumor cell recognition, avoid tumor escape and potentially enhancing the effect of other drugs. In this study, we evaluated the ability of the investigational medicine NKTR-255, an IL-15 receptor agonist, to engage the IL-15 pathway and stimulate NK cells against MM cells. We observed that incubation with NKTR-255 was able to tilt the balance toward an activated phenotype in NK cells isolated from peripheral blood mononuclear cells of patients with MM, with increased expression of activating receptors on the surface of treated NK cells. This resulted in an enhanced degranulation, cytokine release, and anti-tumor cytotoxicity when the NK cells were exposed to both MM cell lines and primary MM cells. We further evaluated the in vivo effect of NKTR-255 in fully humanized immunocompetent mice subcutaneously engrafted with H929 MM cells. Compared with placebo, weekly injection of the mice with NKTR-255 increased the number of circulating NK cells in peripheral blood and delayed tumor growth. Finally, we observed that combination of NKTR-255 with the anti-CD38 antibody, daratumumab, was effective against MM cells in vitro and in vivo. Taken together, our data suggest a significant impact of NKTR-255 in inducing NK cell function against MM cells with important translational implications., (© 2022 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)