IL-2 activation of NK cells: involvement of MKK1/2/ERK but not p38 kinase pathway

The meninges host a unique compartment of regulatory T cells that bulwarks adult hippocampal neurogenesis

Our knowledge about the meningeal immune system has recently burgeoned, particularly our understanding of how innate and adaptive effector cells are mobilized to meet brain challenges. However, information on how meningeal immunocytes guard brain homeostasis in healthy individuals remains sparse. This study highlights the heterogeneous and polyfunctional regulatory-T (Treg) cell compartment in the meninges. A Treg subtype specialized in controlling Th1-cell responses and another known to control responses in B-cell follicles were substantial components of this compartment, foretelling that punctual Treg-cell ablation rapidly unleashed interferon-gamma production by meningeal lymphocytes, unlocked their access to the brain parenchyma, and altered meningeal B-cell profiles. Distally, the hippocampus assumed a reactive state, with morphological and transcriptional changes in multiple glial-cell types; within the dentate gyrus, neural stem cells showed exacerbated death and desisted from further differentiation, associated with inhibition of spatial-reference memory. Thus, meningeal Treg cells are a multifaceted bulwark to brain homeostasis at steady-state.

One sentence summary

A distinct population of regulatory T cells in the murine meninges safeguards homeostasis by keeping local interferon-γ-producing lymphocytes in check, thereby preventing their invasion of the parenchyma, activation of hippocampal glial cells, death of neural stem cells, and memory decay.

Modulatory properties of curcumin in cancer: A narrative review on the role of interferons

The immune network is an effective network of cell types and chemical compounds established to maintain the body's homeostasis from foreign threats and to prevent the risk of a wide range of diseases; hence, its proper functioning and balance are essential. A dysfunctional immune system can contribute to various disorders, including cancer. Therefore, there has been considerable interest in molecules that can modulate the immune network. Curcumin, the active ingredient of turmeric, is one of these herbal remedies with many beneficial effects, including modulation of immunity. Curcumin is beneficial in managing various chronic inflammatory conditions, improving brain function, lowering cardiovascular disease risk, prevention and management of dementia, and prevention of aging. Several clinical studies have supported this evidence, suggesting curcumin to have an immunomodulatory and anti-inflammatory function; nevertheless, its mechanism of action is still not clear. In the current review, we aim to explore the modulatory function of curcumin through interferons in cancers.

Identification and Validation of FGF-Related Prognostic Signatures in Prostate Cancer

Background

FGF signaling is critical to controlling various cancers. Nevertheless, the functions of FGF-related genes in PCa are still unknown.

Objective

The objective of this study is to build a FGF-related signature that was capable of accurately predicting PCa survival and prognosis for BCR.

Methods

The univariate and multivariate Cox regression, infiltrating immune cells, LASSO, and GSEA analyses were carried out to build a prognostic model.

Results

A FGF-related signature that consists of PIK3CA and SOS1 was developed for the purpose of predicting PCa prognosis, and all patients were categorized into low- and high-risk groups. In comparison to the low-risk group, high-risk score patients had poorer BCR survival. This signature's predictive power has been investigated utilizing the AUC of the ROC curves. The risk score has been shown to be an independent prognostic factor by multivariate analysis. The four enriched pathways of the high-risk group were obtained by gene set enrichment analysis (GSEA) and found to be associated with the tumorigenesis and development of PCa, including focal adhesion, TGF-β signaling pathway, adherens junction, and ECM receptor interaction. The high-risk groups had considerably higher levels of immune status and tumor immune cell infiltration, suggesting a more favorable response to immune checkpoint inhibitors. IHC found that the expression of the two FGF-related genes in the predictive signature was extremely different in PCa tissues.

Conclusion

To summarize, our FGF-related risk signature may effectively predict and diagnose PCa, indicating that in PCa patients, they are potential therapeutic targets and promising prognostic biomarkers.

Reactivation of natural killer cells with monoclonal antibodies in the microenvironment of malignant neoplasms

Natural killer cells are critical players in the antitumor immune response due to their ability to destroy target cells through cytotoxic activity and other means. However, this response is inhibited in the tumor microenvironment, where a crippling hypoxic environment and several inhibitory molecules bind to NK cells to trigger an anergic state. Inhibitory receptors such as PD-1, NK2GA, KIR, TIGIT, and LAG-3 have been associated with inhibition of NK cells in multiple cancer types. Binding to these receptors leads to loss of cytotoxicity, lower proliferation and metabolic rates, and even apoptosis. While these receptors are important for avoiding auto-immunity, in a pathological setting like malignant neoplasms they are disadvantageous for the individual's immune system to combat cancer cells. The use of monoclonal antibodies to block these receptors contributes to cancer therapy by preventing the inhibition of NK cells. In this review, the impact of NK cell inhibition and activation on cancer therapy was summarized and an overview of the blockade of inhibitory pathways by monoclonal antibodies was provided.

2'-Fucosyllactose Promotes the Production of Short-Chain Fatty Acids and Improves Immune Function in Human-Microbiota-Associated Mice by Regulating Gut Microbiota

As a natural prebiotic in human milk, 2'-fucosyllactose (2'-FL) is actively used in infant formula (IF). However, the 2'-FL influence on the improvement of gut microbiota and the regulation of the immune function remains unknown. In this study, human microbiota-associated (HMA) mice were used to demonstrate that feeding 2'-FL-containing IF was comparable to human milk at levels of immune cytokines (IL-2, IL-9, IL-10, and sIgA) and short-chain fatty acids (SCFAs, i.e., acetate and propionate). In addition, 2'-FL increased the abundance of Blautia and Olsenella and improved the anti-inflammatory cytokine IL-10 levels. The abundance of Blautia and Olsenella positively correlated with the IL-10 levels. 2'-FL also decreased the abundance of Enterorhabdus and Lachnospiraceae_UCG-006 and elevated SCFA levels, showing a negative correlation between these genera and SCFAs. Our findings revealed that feeding 2'-FL-containing IF drives the levels of cytokines and SCFAs toward human milk levels by shaping the beneficial gut microbiota profile.

Aurantii Fructus Immaturus enhances natural killer cytolytic activity and anticancer efficacy in vitro and in vivo

Aurantii Fructus Immaturus (AFI), extensively used in traditional herbal medicine, is known to have diverse physiological effects against various diseases, including obesity, diabetes, and cardiovascular disease. However, the effects of AFI on the immune system, especially natural killer (NK) cells, remain largely unknown. We aimed to investigate the effect of AFI on NK cell activity in vitro and in vivo and to elucidate the underlying mechanisms. Further, we verified the anticancer efficacy of AFI in a mouse lung metastasis model, underscoring the therapeutic potential of AFI in cancer therapy. Our results revealed that AFI significantly enhanced the cytolytic activity of NK cells in a dose-dependent manner, accompanied by an increase in the expression of NK cell-activating receptors, especially NKp30 and NKp46. AFI treatment also increased the expression of cytolytic granules, including granzyme B and perforin. Furthermore, the expression of CD107a, a degranulation marker, was increased upon treatment with AFI. A signaling study using western blot analysis demonstrated that the phosphorylation of extracellular signal-regulated kinase (ERK) was involved in increasing the NK cell activity following AFI treatment. In the in vivo study performed in mice, oral administration of AFI markedly enhanced the cytotoxic activity of spleen mononuclear cells against YAC-1 cells, which was accompanied by NKp46 upregulation. In addition, we confirmed that cancer metastasis was inhibited in a mouse cancer metastasis model, established using the mouse melanoma B16F10 cell line, by the administration of AFI in vivo. Collectively, these results indicate that AFI enhances NK cell-mediated cytotoxicity in vitro and in vivo via activation of the ERK signaling pathway and suggest that AFI could be a potential supplement for cancer immunotherapy.

Plasmalogen-Mediated Activation of GPCR21 Regulates Cytolytic Activity of NK Cells against the Target Cells

It is widely known that the immune system becomes slower to respond among elderly people, making them more susceptible to viral infection and cancer. The mechanism of aging-related immune deficiency remained mostly elusive. In this article, we report that plasmalogens (Pls), special phospholipids found to be reduced among the elderly population, critically control cytolytic activity of human NK cells, which is associated with activation of a cell surface receptor, G protein-coupled receptor 21 (GPCR21). We found the extracellular glycosylation site of GPCR21, which is conserved among the mammalian species, to be critically important for the activation of NK cells by Pls. The Pls-GPCR21 signaling cascade induces the expression of Perforin-1, a cytolytic pore-forming protein, via activation of STAT5 transcription factor. Inhibition of STAT5 abrogates GPCR21-mediated cytolytic activation of NK cells against the target cancer cells. In addition, oral ingestion of Pls inhibited cancer growth in SCID mice and inhibited the systemic spread of murine CMV in adult C57BL/6J mice. These findings advocate that Pls-GPCR21 signaling could be critical in maintaining NK cell function, and that the age-related reduction of this signaling cascade could be one of the factors behind immune deficiency in mammals, including humans.

STAT1 signaling protects self-reactive T cells from control by innate cells during neuroinflammation

The transcription factor STAT1 plays a critical role in modulating the differentiation of CD4⁺ T cells producing IL-17 and GM-CSF, which promote the development of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). The protective role of STAT1 in MS and EAE has been largely attributed to its ability to limit pathogenic Th cells and promote Tregs. Using mice with selective deletion of STAT1 in T cells (STAT1^CD4-Cre), we identified a potentially novel mechanism by which STAT1 regulates neuroinflammation independently of Foxp3⁺ Tregs. STAT1-deficient effector T cells became the target of NK cell–mediated killing, limiting their capacity to induce EAE. STAT1-deficient T cells promoted their own killing by producing more IL-2 that, in return, activated NK cells. Elimination of NK cells restored EAE susceptibility in STAT1^CD4-Cre mice. Therefore, our study suggests that the STAT1 pathway can be manipulated to limit autoreactive T cells during autoimmunity directed against the CNS.

Oral Administration of Nanopeptide CMCS-20H Conspicuously Boosts Immunity and Precautionary Effect Against Bacterial Infection in Fish

Massive mortalities caused by bacterial infections in intensive aquaculture result in serious economic losses. In this study, a novel antimicrobial peptide gcIFN-20H was efficiently expressed in Pichia pastoris (GS115) and loaded on carboxylmethyl chitosan (CMCS) to prepare CMCS-20H nanoparticles. Through physical characterization assays (TEM, DLS, BCA, and Raman) and biological activity tests (antimicrobial activity and cytotoxicity), CMCS-20H nanopeptide was verified to be spherical nanoparticles with sustained release, antimicrobial activity, and negligible toxicity. CMCS-20H nanoparticles are more resistant to intestinal degradation than unloaded gcIFN-20H by indirect immunofluorescence assay. Oral administration was then carried out for 42 days. Complement C3 content, lysozyme, and total superoxide dismutase activities are highest in CMCS-20H group by serum biochemistry index assays. After challenge with Aeromonas hydrophila, the survival rate in CMCS-20H group is highest (46%), which is 64% higher than the control group (28%). Meanwhile, the tissue bacterial loads (intestine, spleen, head kidney, trunk kidney, hepatopancreas, muscle, and blood) in the CMCS-20H group are significantly lower than other groups. By PAS staining analysis, the number of intestinal villi goblet cells and the thickness of mucin in the CMCS-20H group obviously increased. CMCS-20H effectively enhances mRNA expressions of some important immune genes (IL-1β, IL-6, TNF-α, IL-2, IFN-γ2, and IgM). The minimal tissue lesions (Intestine, spleen, and trunk kidney) were seen in the CMCS-20H group by histopathological examination. 16S rRNA sequencing showed that oral CMCS-20H maintains the intestinal microbiome homeostasis in bacterial infection. The results indicate that the novel nanopeptide CMCS-20H as the immunopotentiator can remarkably boost fish immunity and precautionary effect by oral administration and address the theoretical mechanisms and insights into the promising application prospect in aquaculture.

IL-2/JES6-1 mAb complexes dramatically increase sensitivity to LPS through IFN-γ production by CD25+Foxp3- T cells

Complexes of IL-2 and JES6-1 mAb (IL-2/JES6) provide strong sustained IL-2 signal selective for CD25⁺ cells and thus they potently expand T_reg cells. IL-2/JES6 are effective in the treatment of autoimmune diseases and in protecting against rejection of pancreatic islet allografts. However, we found that IL-2/JES6 also dramatically increase sensitivity to LPS-mediated shock in C57BL/6 mice. We demonstrate here that this phenomenon is dependent on endogenous IFN-γ and T cells, as it is not manifested in IFN-γ deficient and nude mice, respectively. Administration of IL-2/JES6 leads to the emergence of CD25⁺Foxp3^-CD4⁺ and CD25⁺Foxp3^-CD8⁺ T cells producing IFN-γ in various organs, particularly in the liver. IL-2/JES6 also increase counts of CD11b⁺CD14⁺ cells in the blood and the spleen with higher sensitivity to LPS in terms of TNF-α production and induce expression of CD25 in these cells. These findings indicate safety issue for potential use of IL-2/JES6 or similar IL-2-like immunotherapeutics.

Activation of Peripheral Blood Mononuclear Cells and Leptin Secretion: New Potential Role of Interleukin-2 and High Mobility Group Box (HMGB)1

Activation of innate immunity and low-grade inflammation contributes to hyperglycemia and an onset of Type 2 Diabetes Mellitus (T2DM). Interleukin-2 (IL-2), leptin, High Mobility Group Box-1 (HMGB-1), and increased glucose concentrations are mediators of these processes also by modulating peripheral blood mononuclear cells (PBMCs) response. The aim of this study was to investigate if HMGB-1 and IL-2 turn on PBMCs and their leptin secretion. In isolated human PBMCs and their subpopulations from healthy individuals and naïve T2DM patients, leptin release, pro-inflammatory response and Toll-like Receptors (TLRs) activation was measured. After treatment with IL-2 and HMGB1, NK (Natural Killer) have the highest amount of leptin secretion, whilst NK-T have the maximal release in basal conditions. TLR4 (TAK242) and/or TLR2 (TLR2-IgA) inhibitors decreased leptin secretion after IL-2 and HMGB1 treatment. A further non-significant increase in leptin secretion was reported in PBMCs of naive T2DM patients in response to IL-2 and HMGB-1 stimulation. Finally, hyperglycemia or hyperinsulinemia might stimulate leptin secretion from PBMCs. The amount of leptin released from PBMCs after the different treatments was enough to stimulate the secretion of IL-1β from monocytes. Targeting leptin sera levels and secretion from PBMCs could represent a new therapeutic strategy to counteract metabolic diseases such as T2DM.

The effect of IL-2 stimulation and treatment of TRPM3 on channel co-localisation with PIP2 and NK cell function in myalgic encephalomyelitis/chronic fatigue syndrome patients

BACKGROUND

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a serious multifactorial disorder. The origin remains ambiguous, however reduced natural killer (NK) cell cytotoxicity is a consistent immunological feature of ME/CFS. Impaired transient receptor potential melastatin 3 (TRPM3), a phosphatidylinositol dependent channel, and impaired calcium mobilisation have been implicated in ME/CFS pathology. This investigation aimed to examine the localisation of TRPM3 at the NK cell plasma membrane and co-localisation with phosphatidylinositol 4,5-bisphosphate (PIP₂). The effect of IL-2 priming and treatment using pregnenolone sulfate (PregS) and ononetin on TRPM3 co-localisation and NK cell cytotoxicity in ME/CFS patients and healthy controls (HC) was also investigated.

METHODS

NK cells were isolated from 15 ME/CFS patients and 15 age- and sex-matched HC. Immunofluorescent technique was used to determine co-localisation of TRPM3 with the NK cell membrane and with PIP₂ of ME/CFS patients and HC. Flow cytometry was used to determine NK cell cytotoxicity. Following IL-2 stimulation and treatment with PregS and ononetin changes in co-localisation and NK cell cytotoxicity were measured.

RESULTS

Overnight treatment of NK cells with PregS and ononetin resulted in reduced co-localisation of TRPM3 with PIP₂ and actin in HC. Co-localisation of TRPM3 with PIP₂ in NK cells was significantly reduced in ME/CFS patients compared with HC following priming with IL-2. A significant increase in co-localisation of TRPM3 with PIP₂ was reported following overnight treatment with ononetin within ME/CFS patients and between groups. Baseline NK cell cytotoxicity was significantly reduced in ME/CFS patients; however, no changes were observed following overnight incubation with IL-2, PregS and ononetin between HC and ME/CFS patients. IL-2 stimulation significantly enhanced NK cell cytotoxicity in HC and ME/CFS patients.

CONCLUSION

Significant changes in co-localisation suggest PIP₂-dependent TRPM3 function may be impaired in ME/CFS patients. Stimulation of NK cells with IL-2 significantly enhanced cytotoxic function in ME/CFS patients demonstrating normal function compared with HC. A crosstalk exists between IL-2 and TRPM3 intracellular signalling pathways which are dependent on Ca²⁺ influx and PIP₂. While IL-2R responds to IL-2 binding in vitro, Ca²⁺ dysregulation and impaired intracellular signalling pathways impede NK cell function in ME/CFS patients.

Cell-cell interactions via non-covalent click chemistry

Metabolic glycoengineering with unnatural sugars became a valuable tool for introducing recognition markers on the cell membranes via bioorthogonal chemistry. By using this strategy, we functionalized the surface of tumor and T cells using complementary artificial markers based on both β-cyclodextrins (β-CDs) and adamantyl trimers, respectively. Once tied on cell surfaces, the artificial markers induced cell-cell adhesion through non-covalent click chemistry. These unnatural interactions between A459 lung tumor cells and Jurkat T cells triggered the activation of natural killer (NK) cells thanks to the increased production of interleukin-2 (IL-2) in the vicinity of cancer cells, leading ultimately to their cytolysis. The ready-to-use surface markers designed in this study can be easily inserted on the membrane of a wide range of cells previously submitted to metabolic glycoengineering, thereby offering a simple way to investigate and manipulate intercellular interactions.

The inhibitory receptor Tim-3 fails to suppress IFN-γ production via the NFAT pathway in NK-cell, unlike that in CD4+ T cells

Background

T cell immunoglobulin and mucin domain-containing-3 (Tim-3) is a negative regulator expressed on T cells, and is also expressed on natural killer (NK) cells. The function of Tim-3 chiefly restricts IFNγ-production in T cells, however, the impact of Tim-3 on NK cell function has not been clearly elucidated.

Results

In this study, we demonstrated down-regulation of Tim-3 expression on NK cells while Tim-3 is upregulated on CD4⁺ T cells during HIV infection. Functional assays indicated that Tim-3 mediates suppression of CD107a degranulation in NK cells and CD4⁺ T cells, while it fails to inhibit the production of IFN-γ by NK cells. Analyses of downstream pathways using an antibody to block Tim-3 function demonstrated that Tim-3 can inhibit ERK and NFκB p65 signaling; however, it failed to suppress the NFAT pathway. Further, we found that the NFAT activity in NK cells was much higher than that in CD4⁺ T cells, indicating that NFAT pathway is important for promotion of IFN-γ production by NK cells.

Conclusions

Thus, our data show that the expression of Tim-3 on NK cells is insufficient to inhibit IFN-γ production. Collectively, our findings demonstrate a potential mechanism of Tim-3 regulation of NK cells and a target for HIV infection immunotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-021-00417-9.

Staphylococcus aureus β-Hemolysin Up-Regulates the Expression of IFN-γ by Human CD56bright NK Cells

IFN-γ is produced upon stimulation with S. aureus and may play a detrimental role during infection. However, whether hemolysins play a role in the mechanism of IFN-γ production has not been fully characterized. In this study, we demonstrated that Hlb, one of the major hemolysins of S. aureus, upregulated IFN-γ production by CD56^bright NK cells from human peripheral blood mononuclear cells (PBMCs). Further investigation showed that Hlb increased calcium influx and induced phosphorylation of ERK1/2. Either blocking calcium or specifically inhibiting phosphorylation of ERK1/2 decreased the production of IFN-γ induced by Hlb. Moreover, we found that this process was dependent on the sphingomyelinase activity of Hlb. Our findings revealed a novel mechanism of IFN-γ production in NK cells induced by Hlb, which may be involved in the pathogenesis of S. aureus.

α-Pinene Enhances the Anticancer Activity of Natural Killer Cells via ERK/AKT Pathway

Natural killer (NK) cells are lymphocytes that can directly destroy cancer cells. When NK cells are activated, CD56 and CD107a markers are able to recognize cancer cells and release perforin and granzyme B proteins that induce apoptosis in the targeted cells. In this study, we focused on the role of phytoncides in activating NK cells and promoting anticancer effects. We tested the effects of several phytoncide compounds on NK-92mi cells and demonstrated that α-pinene treatment exhibited higher anticancer effects, as observed by the increased levels of perforin, granzyme B, CD56 and CD107a. Furthermore, α-pinene treatment in NK-92mi cells increased NK cell cytotoxicity in two different cell lines, and immunoblot assays revealed that the ERK/AKT pathway is involved in NK cell cytotoxicity in response to phytoncides. Furthermore, CT-26 colon cancer cells were allografted subcutaneously into BALB/c mice, and α-pinene treatment then inhibited allografted tumor growth. Our findings demonstrate that α-pinene activates NK cells and increases NK cell cytotoxicity, suggesting it is a potential compound for cancer immunotherapy.

Cationic Nanoparticle-Mediated Activation of Natural Killer Cells for Effective Cancer Immunotherapy

Natural killer (NK) cells have been recognized as a next-generation therapy for cancer as they are less likely to trigger adverse events (e.g., cytokine storm or graft-versus-host disease) than T cell-based therapeutics. Although NK cell activation strategies through genetic engineering and cytokine treatment have been actively studied for successful cancer treatment, the approaches are inefficient, expensive, and involve complex processing. Here, we developed a facile and efficient method of activating NK cells using cationic nanoparticles (cNPs). The cytotoxic activity of cNP-treated primary NK and NK-92MI cells against triple-negative breast cancer cells was over 2-fold higher than that of control NK cells in vitro. Molecular biological analyses confirmed that cNPs altered the expression of CCR4 and CXCR4 of NK cells that function as chemokine receptors. In vitro live cell imaging showed that the NK cells treated with cNPs were better than control NK cells at interacting with cancer cells. Consistent with these in vitro results, cNP-treated NK cells effectively inhibited tumor growth in an in vivo tumor animal model of triple-negative breast cancer. Additionally, NK cells treated with cNPs were tracked effectively in vivo by magnetic resonance imaging. Thus, cNP-mediated activation of NK cells has great potential as an NK cell-based cancer immunotherapy. Most of all, activating NK cells using cNPs has a great advantage over conventional methods in that immune cells can be activated by a one-step facile process with exogenously charged nanomaterials, without the need for genetic engineering or cytokine treatment.

Molecular Remission Using Low-Dose Immunotherapy with Minimal Toxicities for Poor Prognosis IGHV- Unmutated Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) accounts for 10% of hematologic malignancies. CLL is a malignancy of CD5+ B cells and it is characterized by the accumulation of small, mature-appearing neoplastic lymphocytes in the blood, bone marrow, and secondary lymphoid tissues. In the present case, a middle-aged female patient with poor prognosis unmutated IGHV CLL achieved cytogenetic and molecular remission with minimal adverse events following six cycles of low dose recombinant human IL-2 (rIL-2) in combination with low dose targeted venetoclax. Personalized low dose rIL-2 in combination with either lenalidomide or venetoclax mediates natural killer stimulation and is an effective non-toxic immunotherapy administered in the outpatient setting for poor prognosis CLL.

Distinct modes of action of CD40L and adaptive cytokines IL-2, IL-4/13, IL-10 and IL-21 on rainbow trout IgM+ B cells

In mammals, conventional B (B2) cells are activated within lymphoid follicles through a close relationship with T follicular helper (Tfh) cells. The interaction between CD40 expressed on B cells and its ligand (CD40L) expressed on Tfh cells is a key signal that regulates the formation of germinal centers (GCs), B cell survival, proliferation and differentiation to plasma cells (PCs) or memory cells. Additionally, certain soluble cytokines produced by T cells also strongly condition the outcome of this interaction. Despite the many differences found between fish B cells and mammalian B2 cells, and the lack of conventional GCs, rainbow trout IgM⁺ B cells have been shown to be stimulated by CD40L, however, whether cytokines commonly produced by T cells can further modulate this response has never been addressed to date. Thus, in this study, we determined the effects of recombinant rainbow trout adaptive cytokines interleukin 2B (IL-2B), IL-4/13A, IL-4/13B, IL-10 and IL-21 (cytokines known to activate B cells in mammals) on splenic IgM⁺ B cells alone or in combination with CD40L. We studied how these cytokines and CD40L cooperated to promote IgM⁺ B cell survival, proliferation and IgM secretion. The results obtained provide valuable information for the first time in teleost fish on how different T cell signals cooperate to activate B cells in the absence of GCs.

The Combination of Molecular Adjuvant CCL35.2 and DNA Vaccine Significantly Enhances the Immune Protection of Carassius auratus gibelio against CyHV-2 Infection

Cyprinid herpesvirus 2 (CyHV-2) infection results in huge economic losses in gibel carp (Carassius auratus gibelio) industry. In this study, we first constructed recombinant plasmids pcORF25 and pcCCL35.2 as DNA vaccine and molecular adjuvant against CyHV-2, respectively, and confirmed that both recombinant plasmids could be effectively expressed in vitro and in vivo. Then, the vaccination and infection experiments (n = 50) were set as seven groups. The survival rate (70%) in ORF25/CCL35.2 group was highest. The highest specific antibody levels were found in ORF25/CCL35.2 group in major immune tissues by qRT-PCR, and confirmed in serum by ELISA assay, antibody neutralization titer, and serum incubation-infection experiments. Three crucial innate immune indices, namely C3 content, lysozyme, and total superoxide dismutase (TSOD) activities, were highest in ORF25/CCL35.2 group in serum. pcORF25/pcCCL35.2 can effectively up-regulate mRNA expressions of some important immune genes (IL-1β, IL-2, IFN-γ2, and viperin), and significantly suppress CyHV-2 replication in head kidney and spleen tissues. The minimal tissue lesions can be seen in ORF25/CCL35.2 group in gill, spleen, and trunk kidney tissues by histopathological examination. The results indicated that the combination of DNA vaccine pcORF25 and molecular adjuvant pcCCL35.2 is an effective method against CyHV-2 infection, suggesting a feasible strategy for the control of fish viral diseases.

Natural killer and NKT cells in the male reproductive tract

Natural killer (NK) cells are important effector lymphocytes that play a pivotal role in the innate and adaptive immune responses to tumors and viral infection. NKT cells are a heterogeneous group of T cells that share properties with both T cells and NK cells. They display immunoregulatory properties as they facilitate the cell-mediated immune response to tumors and infectious diseases, and inhibit cell-mediated immunity associated with autoimmune diseases and allograft rejection. However, the roles of NK and NKT cells in the male reproductive tract remain largely unexplored, in particular, NKT cells, tissue distribution, and state of health or disease. Infection and inflammation of the male genital tract are thought to be the primary etiological factors of male infertility. In this review, we considered this complex and rapidly growing field. We summarize the recent findings and the characterization and roles of NK and NKT cells in the male reproductive tract, including the testis, epididymis, prostate, seminal vesicle, and semen, to enhance our understanding of the immunological mechanisms of male infertility and for the design effective vaccines for male reproductive health in the future.

The Role of Arginine in Disease Prevention, Gut Microbiota Modulation, Growth Performance and the Immune System of Broiler Chicken – A Review

The effect of dietary arginine on disease prevention, immune system modulation, the gut micro-biota composition and growth of broiler chicken was reviewed. The main aim of poultry production is the maximization of profit at the least possible cost. This objective can mainly be achieved by ensuring that there is no interference in growth or disease outbreak and by feeding chicken with the best possible level of nutrients. With the ban on antibiotic growth promoters, attention is shifted towards other nutrition methods to prevent diseases and promote growth. More attention is therefore given to protein diets in animal nutrition due to their importance as essential part of active biological compounds in the body, assisting in the breakdown of body tissue and helping in the physiological processes of the animal. Arginine plays important function in serving as building blocks of proteins and polypeptides. It performs other roles during the regulation of important biochemical functions such as maintenance, growth, reproduction and immunity. Arginine cannot be synthesized by the body so it has to be supplemented in the diet. When arginine is supplemented above the recommended level, the gut mucosa is protected, immunosuppression is alleviated, diseases like necrotic enteritis, infectious bursal disease and coccidiosis in broiler chickens are prevented. There is an improvement in growth resulting from the increase in intestinal absorption, barrier function and microbiota composition.

Interleukin-2 (IL-2) of flounder (Paralichthys olivaceus) as immune adjuvant enhance the immune effects of E. tarda subunit vaccine OmpV against Edwardsiellosis

In our previous study, we cloned and explored the biological functions of flounder (Paralichthys olivaceus) interleukin-2 (poIL-2), and showed that poIL-2 might have adjuvant potential for fish vaccines. In this study, the adjuvant effects of recombinant and molecular forms of poIL-2 (rIL-2 and pcIL-2) were comparatively analyzed and evaluated in flounder from several aspects by co-vaccination with the recombinant E. tarda OmpV (rOmpV). The results showed that co-vaccination with rOmpV plus rIL-2 or pcIL-2 resulted in a relative percent survival of 71% and 57% respectively, which was significantly higher than the control groups, rOmpV plus rHis (40%) or pcN3 (36%). Immunological analysis showed that: (1) the levels of specific serum antibodies and sIg + lymphocytes in head kidney, spleen and peripheral blood induced by rOmpV plus rIL-2 or pcIL-2 were significantly higher than that in the two control groups; (2) Compared to the two control groups, CD4-1, CD4-2, CD8α, CD8β, MHCIα, MHCIIα, IgM and IFN-γ mRNA levels were also significantly induced by rOmpV plus rIL-2 or pcIL-2; (3) the rOmpV plus rIL-2 could induce higher levels of sIg + lymphocytes, specific serum antibodies and the expressions of all investigated genes than rOmpV plus pcIL-2. These results demonstrated that co-vaccination with rOmpV with rIL-2 or pcIL-2 could induce stronger humoral and cellular immune responses, and evoked higher immune protective efficacy against E. tarda infection, suggesting that poIL-2 could be served as a promising candidate adjuvant and have a potential application in the control of flounder diseases.

Lack of cell movement impairs survival of peripheral blood IL-2-stimulated natural killer cells originating from solid cancer and promotes red blood cells to induce their switch toward a regulatory phenotype

BACKGROUND

Red blood cells (RBCs) can have a modulatory effect on immune cells; so changes in their dynamism could considerably influence their physiology, and consequently the immune activities of neighbouring cells, like natural killer (NK) cells. Herein, we studied the effect of both RBCs and lack of cell movement on the proliferation, survival and regulation of peripheral IL-2-stimulated NK cells from normal and solid malignant conditions.

METHODS

Experiments were conducted on twelve cell culture groups, including NK cells from patients with solid malignant tumor or healthy controls, cultured alone or with autologous or nonautologous RBCs under shaking or no shaking conditions.

RESULTS

NK cells from neoplastic patients behaved differently depending on the culture conditions including shaking and/or RBCs presence. Therefore, NK cells survival was downregulated in the absence of shaking; whereas, shaking have not only upregulated cell survival, but also downregulated the levels of p53-related apoptosis. Moreover, RBCs enhanced NK cells proliferation; while, this effect was modulated by shaking. Furthermore, RBCs can generate opposite effects on the production and modulation of protumoral or immunosuppressive cytokines, depending on the origin of NK cells, i.e., whether they derive from healthy or solid malignant tumor conditions. Finally, NK cells become able to express Foxp3 regulatory marker when combining three main conditions that include (i) treatment with high dose of IL-2, (ii) presence of RBCs, and (iii) absence of shaking.

CONCLUSIONS

Our outcomes showed for the first time that cell stagnation would be markedly involved in peripheral NK cell apoptosis, as well as in switching toward a regulatory phenotype-induced Foxp3. Cell movement may be one of ex vivo potential approaches in boosting the activities and survival of such cells during solid cancer.

Transient receptor potential melastatin 2 channels are overexpressed in myalgic encephalomyelitis/chronic fatigue syndrome patients

Background

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is hallmarked by a significant reduction in natural killer (NK) cell cytotoxicity, a mechanism tightly regulated by calcium (Ca²⁺). Interestingly, interleukin-2 (IL-2) increases NK cell cytotoxicity. Transient receptor potential melastatin 2 (TRPM2) ion channels are fundamental for Ca²⁺ signalling in NK cells. This pilot investigation aimed to characterise TRPM2 and CD38 surface expression in vitro on NK cells in ME/CFS patients. This investigation furthermore examined the pharmaceutical effect of 8-bromoadenosine phosphoribose (8-Br-ADPR) and N₆-Benzoyladenosine-3′,5′-cyclic monophosphate (N₆-Bnz-cAMP) on TRPM2 and CD38 surface expression and NK cell cytotoxicity between ME/CFS and healthy control (HC) participants.

Methods

Ten ME/CFS patients (43.45 ± 12.36) and 10 HCs (43 ± 12.27) were age and sex-matched. Isolated NK cells were labelled with fluorescent antibodies to determine baseline and drug-treated TRPM2 and CD38 surface expression on NK cell subsets. Following IL-2 stimulation, NK cell cytotoxicity was measured following 8-Br-ADPR and N₆-Bnz-cAMP drug treatments by flow cytometry.

Results

Baseline TRPM2 and CD38 surface expression was significantly higher on NK cell subsets in ME/CFS patients compared with HCs. Post IL-2 stimulation, TRPM2 and CD38 surface expression solely decreased on the CD56^DimCD16⁺ subset. 8-Br-ADPR treatment significantly reduced TRPM2 surface expression on the CD56^BrightCD16^Dim/− subset within the ME/CFS group. Baseline cell cytotoxicity was significantly reduced in ME/CFS patients, however no changes were observed post drug treatment in either group.

Conclusion

Overexpression of TRPM2 on NK cells may function as a compensatory mechanism to alert a dysregulation in Ca²⁺ homeostasis to enhance NK cell function in ME/CFS, such as NK cell cytotoxicity. As no improvement in NK cell cytotoxicity was observed within the ME/CFS group, an impairment in the TRPM2 ion channel may be present in ME/CFS patients, resulting in alterations in [Ca²⁺]_i mobilisation and influx, which is fundamental in driving NK cell cytotoxicity. Differential expression of TRPM2 between NK cell subtypes may provide evidence for their role in the pathomechanism involving NK cell cytotoxicity activity in ME/CFS.

The forkhead transcription factor Foxo3 negatively regulates natural killer cell function and viral clearance in myocarditis

Aims

Foxo3 is a transcription factor involved in cell metabolism, survival, and inflammatory disease. However, mechanistic insight in Foxo3 effects is still limited. Here, we investigated the role of Foxo3 on natural killer (NK) cell responses and its effects in viral myocarditis.

Methods and results

Effects of Foxo3 on viral load and immune responses were investigated in a model of coxsackie virus B3 myocarditis in wild-type (WT) and Foxo3 deficient mice. Reduced immune cell infiltration, viral titres, and pro-inflammatory cytokines in cardiac tissue were observed in Foxo3-/- mice 7 days post-infection (p.i.). Viral titres were also attenuated in hearts of Foxo3-/- mice at Day 3 while interferon-γ (IFNγ) and NKp46 expression were up-regulated suggesting early viral control by enhanced NK cell activity. CD69 expression of NK cells, frequencies of CD11b+CD27+ effector NK cells and cytotoxicity of Foxo3-/- mice was enhanced compared to WT littermates. Moreover, microRNA-155 expression, essential in NK cell activation, was elevated in Foxo3-/- NK cells while its inhibition led to diminished IFNγ production. Healthy humans carrying the longevity-associated FOXO3 single nucleotide polymorphism (SNP) rs12212067 exhibited reduced IFNγ and cytotoxic degranulation of NK cells. Viral inflammatory cardiomyopathy (viral CMI) patients with this SNP showed a poorer outcome due to less efficient virus control.

Conclusion

Our results implicate Foxo3 in regulating NK cell function and suggest Foxo3 playing an important role in the antiviral innate immunity. Thus, enhanced FOXO3 activity such as in the polymorphism rs12212067 may be protective in chronic inflammation such as cancer and cardiovascular disease but disadvantageous to control acute viral infection.

Mass Cytometry Reveals a Sustained Reduction in CD16+ Natural Killer Cells Following Chemotherapy in Colorectal Cancer Patients

The immune system and inflammation plays a significant role in tumour immune evasion enhancing disease progression and reducing survival in colorectal cancer (CRC). Patients with advanced stages of colorectal cancer will all undergo treatment with cytotoxic chemotherapy which may alter the complexity of immune cell populations. This study used mass cytometry to investigate the circulating immune cell profile of advanced CRC patients following acute and chronic doses of standard cytotoxic chemotherapy and analysed seven major immune cell populations and over 20 subpopulations. Unsupervised clustering analysis of the mass cytometry data revealed a decrease in NK cells following one cycle of cytotoxic chemotherapy. Investigation into the NK sub-population revealed a decline in the CD56^dim CD16⁺ NK cell population following acute and chronic chemotherapy treatment. Further analysis into the frequency of the NK cell sub-populations during the long-term chemotherapy treatment revealed a shift in the sub-populations, with a decrease in the mature, cytotoxic CD56^dim CD16⁺ accompanied by a significant increase in the less mature CD56^dim CD16^- and CD56^bright NK cell populations. Furthermore, analysis of the phosphorylation status of signalling responses in the NK cells found significant differences in pERK, pP38, pSTAT3, and pSTAT5 between the patients and healthy volunteers and remained unchanged throughout the chemotherapy. Results from this study reveals that there is a sustained decrease in the mature CD16⁺ NK cell sub-population frequency following long-term chemotherapy which may have clinical implications in therapeutic decision making.

Interleukin-2 (IL-2) in flounder (Paralichthys olivaceus): Molecular cloning, characterization and bioactivity analysis

Interleukin-2 (IL-2) is mainly produced by CD4⁺ T helper lymphocytes, which is an important immunomodulatory cytokine that primarily promotes activation, proliferation and differentiation of T cells. In the present study, flounder (Paralichthys olivaceus) interleukin 2 homologue (poIL-2) was identified for the first time, and its expression patterns were characterized in healthy, virus- or bacteria-infected flounder. The full-length cDNA sequences of poIL-2 was 989 bp with an open reading frame of 423 bp coding a polypeptide of 140 amino acids (aa). The deduced aa sequences shared low similarities (<53%) with other known fish IL-2s. Multiple alignment of aa sequences revealed that poIL-2 own the classical IL-2 family signature of "C-X(3)-EL-X(2)-(T/V)-(V/M/L)-(K/T/R)-X-EC" and "DS-X-(F/L)Y(A/T/S)P". In healthy flounder, IL-2 mRNA was highly expressed in PBLs, spleen and hindgut, and moderately expressed in gill, trunk kidney and stomach. PHA, LPS and Con-A could effectively induce poIL-2 expression in primary cultured peripheral blood leukocytes in vitro. poIL-2 transcripts were significantly up-regulated in spleen, kidney, gill and hindgut post infections with Edwardsiella tarda and Hirame novirhabdovirus (HIRRV). The eukaryotic expression vector encoding poIL-2 (pcIL-2) was constructed and intramuscularly injected, which could be successfully expressed in flounders and induced significantly higher expressions of six immune related genes including poIL-2, β-defensin, CD4-1, CD8α, IFN-γ and TNF-α compared with the injection with control plasmid. Moreover, pretreatment with pcIL-2 could markedly increase the survival rate of flounder challenged with HIRRV. Our results demonstrated that poIL-2 plays an important role in the induction of immune responses and immune defense against bacterial and virus infection, which indicated its potential use as an immunopotentiator to prevent diseases in flounder.

Immunological characteristics of Interleukin-2 receptor subunit beta (IL-2Rβ) in flounder (Paralichtlys olivaceus): Implication for IL-2R function

Interleukin-2 receptor subunit beta of flounder (Paralichthys olivace, fIL-2Rβ) was annotated on the NCBI, its gene was cloned and characterized functionally in this study. And then the amino acids sequences and tertiary structure of fIL-2Rβ were analyzed, respectively. RT-PCR and ImageJ analyzed showed that fIL-2Rβ mRNA were expressed in the gill, spleen, kidney, intestines, liver, blood, muscle and skin, which showed high signals in spleen and blood. And then the recombinant protein of fIL-2Rβ extracellular region and its polyclonal antibodies were produced, native fIL-2Rβ molecules in flounder peripheral blood leukocytes (PBLs) were identified at 60.7 kDa by Mass spectrometry, which were in accordance with the molecular mass of full fIL-2Rβ protein calculated on the predicted protein sequence. Then the IL-2Rβ+ cell in T/B lymphocytes were characterized by Flow cytometry and indirect immunofluorescence assay, respectively. The results showed that the percentages of IL-2Rβ+ leukocytes, IL-2Rβ+/CD4+, IL-2Rβ+/IgM+ lymphocytes were 18.4 ± 2.7%, 4.5 ± 0.8%, 4.3% ± 0.5 in PBLs, and were 13.6 ± 0.9%, 4.6 ± 1.1%, 6.1% ± 0.4 in spleen, similarly, the percentages of IL-2Rβ+ leukocytes, IL-2Rβ+/CD4+, IL-2Rβ+/IgM+ lymphocytes were 9.4 ± 0.3%, 4.0 ± 0.5%, 5.7 ± 0.1% in head kidney, respectively. After KLH injection, compared with control group, the gene expression of IL-2, IL-2Rβ, CD3, TCR, CD79b and IgM in spleen of flounder were up-regulated, respectively (p < 0.05). And the FCM results showed that the percentages of IL-2Rβ+ leukocytes in PBLs were significantly increased post Keyhole limpet hemocyanin (KLH) injection, which peaked 23.9 ± 0.9% at 9^th day (p < 0.05). To our knowledge, those results first reported that the characteristics of IL-2R and IL-2R + molecules were expressed on both B and T lymphocytes in fish. At the same time, this study lays a foundation for further exploring the interaction between IL-2 and IL-2R to promote cell proliferation and carrying out biological functions.

Current Concepts in Natural Killer Cell Biology and Application to Drug Safety Assessments

Natural killer (NK) cells are lymphocytes capable of cytotoxicity against virally infected cells and tumor cells. The display of effector function by NK cells is the result of interactions between germline encoded activating/inhibitory NK cell receptors and their ligands (major histocompatibility complex class I, major histocompatibility complex class I-like, viral, and cellular stress-related surface molecules) expressed on target cells. Determination of NK cell number and function is a common element of the immunotoxicology assessment paradigm for the development of certain classes of pharmaceuticals across a range of modalities. This article summarizes the evidence associating NK cell dysfunction with infectious and cancer risks, reviews emerging NK cell biology, including the impact of immunogenetics on NK cell education and function, and provides perspectives about points to consider when assessing NK cell function in different species in the context of safety assessment.

The Oleaceae family: A source of secoiridoids with multiple biological activities

In the quest to search and discover bioactive compounds from nature, terpenoids have emerged as one of the most interesting and researched classes of compounds. Secoiridoid, a type of the terpenoid, has also been extensively studied, especially their chemical structures and pharmacological effects. Oleaceae is a family of woody dicotyledonous plants with broad economic and medicinal values. This family contains a large number of flavonoids, monoterpenoids, iridoids, secoiridoids and phenylethyl alcohols, of which the secoiridoids have various biological activities. The purpose of this review is to summarize the phytochemical and pharmacological of the secoiridoids (glycosides, aglycones, derivatives and dimers) in the Oleaceae family from 1987 to 2018. This review will also serve as a reference for further studies.

Humanized anti-CD123 antibody facilitates NK cell antibody-dependent cell-mediated cytotoxicity (ADCC) of Hodgkin lymphoma targets via ARF6/PLD-1

CD123 (IL-3Rα) is frequently expressed by malignant Hodgkin lymphoma (HL) cells. Naked monoclonal antibodies (mAb) against HL lack clinical benefit, partially due to absence of natural killer (NK) cells in the tumor microenvironment. Here we show that the combination of a fully humanized anti-CD123 mAb (CSL362) and high-affinity Fcγ-receptor NK-92 cells (haNK) effectively target and kill HL cells in vitro. First, we confirmed high expression of CD123 in 2 of the 3 HL cell lines (KM-H2 and L-428), and its absence in NK cells. Cytotoxicity of haNK cells against CD123-positive HL cells was significantly higher in the presence of CSL362. This was also shown with IL-15-activated primary NK cells, although haNK cells showed a 10.87-fold lower estimated half-maximal stimulatory effective concentration (EC₅₀). CSL362 facilitated a significant increase in the expression of CD107a, intracellular IFN-γ and TNF-α and enhanced expression of c-JUN, PLD-1, and ARF6 by NK cells. Inhibition of the ARF6–PLD-1 axis (NAV2729), but not of the MAPK pathway (U0126), completely abrogated CSL362-facilitated antibody-dependent cell-mediated cytotoxicity (ADCC) in haNK and activated primary NK cells. Our results support CD123 as an immunotherapeutic target for HL and the combination of NK cells and CSL362 as a treatment strategy for HL.

Antibody immunoglobulin G1 and immunoglobulin G2a responses against some cystic fluid proteins of Cysticercus bovis in Balb/c mice

Background and Aim:

Immunoglobulin (Ig) G1 and IgG2a are the surrogate markers respectively for humoral and cellular immune responses of hosts against antigens including cystic fluid proteins of Cysticercus bovis. A study was conducted to investigate the IgG1 and IgG2a responses of Balb/c mice against some individual cystic fluid proteins of C. bovis in an effort to determine the roles of each protein in inducing the humoral and cellular immune responses in host.

Materials and Methods:

Individual p71, p31, and p14 proteins of C. bovis were purified by separation of the proteins using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and elution of individual proteins from the gel. Six female Balb/c mice were immunized 4 times at 10-day intervals with the crude cystic fluid proteins, and sera were collected for the measurement of IgG1 and IgG2a levels against the individual proteins. Sera samples collected before the first immunization were used as negative antibody control, sera samples collected after the fourth immunization were used as positive antibody control, and crude cystic fluid protein was used as positive antigen control.

Results:

All immunized mice were immune to p71, p31, p14, and crude cystic fluid proteins of C. bovis. The crude cystic fluid proteins of C. bovis induced a higher IgG2a than IgG1 level following the first and the second immunizations but switched into a higher IgG1 than IgG2a level following the fourth immunization. Protein 71 kDa (p71) induced a higher IgG2a than IgG1 level following the fourth immunization. In contrast, p14 induced a higher IgG1 than IgG2a level following the fourth immunization. Low and balance IgG1 and IgG2a levels against p31 were observed following the first to the fourth immunizations.

Conclusion:

Using IgG1 and IgG2a levels as the surrogate markers, it appears that cystic fluid antigens of C. bovis induce both humoral and cellular immune responses in Balb/c mice. The p71 appears to be a better inducer of cellular immune response, whereas p14 is a better inducer of humoral immune response of mice.

CD56bright cells respond to stimulation until very advanced age revealing increased expression of cellular protective proteins SIRT1, HSP70 and SOD2

BACKGROUND

NK cells are cytotoxic lymphocytes of innate immunity composed of: cytotoxic CD56dim and immunoregulatory CD56bright cells. The study aimed to analyze the expression of cellular protective proteins: sirtuin 1 (SIRT1), heat shock protein 70 (HSP70) and manganese superoxide dismutase (SOD2) in CD56dim and CD56bright NK cells of the young, seniors aged under 85 ('the old') and seniors aged over 85 ('the oldest'). We studied both non-stimulated NK cells and cells stimulated by IL-2, LPS or PMA with ionomycin. The expression level of proinflammatory cytokines TNF and IFN-γ was also assessed in NK cell subsets and some relationships between the studied parameters were analyzed.

RESULTS

CD56bright cells showed sensitivity to most of the applied stimulatory agents until very advanced age in regards to the expression of SIRT1 and intracellular HSP70. On the contrary, CD56dim cells, sensitive to stimulation by most of the stimulatory agents in the young and the old, in the oldest lost this sensitivity and presented rather high, constant expression of SIRT1 and HSP70, resistant to further stimulation. With reference to SOD2 expression, CD56dim cells were insensitive to stimulation in the young, but their sensitivity increased with ageing. CD56bright cells were sensitive to most of the applied agents in the young and the old but in the oldest they responded to all of the stimulatory agents used in the study. Similarly, both NK cell subsets were sensitive to stimulation until very advanced age in regards to the expression of TNF and IFN-γ.

CONCLUSIONS

CD56bright cells maintained sensitivity to stimulation until very advanced age presenting also an increased expression of SIRT1 and HSP70. CD56dim cells showed a constantly increased expression of these cellular protective proteins in the oldest, insensitive for further stimulation. The oldest, however, did not reveal an increased level of SOD2 expression, but it was significantly elevated in both NK cell subsets after stimulation.The pattern of expression of the studied cellular protective proteins in ageing process revealed the adaptation of NK cells to stress response in the oldest seniors which might accompany the immunosenescence and contribute to the long lifespan of this group of the elderly.

Molecular cloning and bioactivity of an IL-2 homologue in large yellow croaker (Larimichthys crocea)

Interleukin-2 (IL-2), an important immunomodulatory cytokine, plays a crucial role in promoting the proliferation, activation and differentiation of T cells. Here, the cDNA of an IL-2 homologue (LcIL-2) in large yellow croaker (Larimichthys crocea) was cloned by RACE-PCR techniques. The open reading frame (ORF) of LcIL-2 gene is 426 bp long and encoded a precursor protein of 141 amino acids (aa), with a 20-aa signal peptide and a 121-aa mature peptide containing two putative N-glycosylation sites at Asn⁷⁷ and Asn¹⁰¹. The LcIL-2 is preferentially expressed in lymphocytes-rich tissues, such as spleen and blood, and is increased in head kidney and spleen upon inactivated trivalent bacterial vaccine or poly(I:C) stimulation. LcIL-2 expression could also be detected in primary head kidney leukocytes (PKL), primary head kidney macrophages (PKM) and primary head kidney granulocytes (PKG), with the highest level in PKL. In addition, the expression level of LcIL-2 in PKL was slightly induced by LPS or poly(I:C), while markedly induced by PHA or Con-A. The recombinant LcIL-2 protein produced in Pichia pastoris could increase the expression of genes involved in Th1 (IL-2, IFN-γ and T-bet) and Th2 (IL-4/13A, IL-4/13B and GATA3) development and differentiation, and of the IL-2 downstream transcription factor STAT5B gene, but inhibit the expression of genes related to Th17 (IL-17A/F2 and IL-17A/F3) development and differentiation. Taken together, our results indicated that LcIL-2 possesses similar structural and functional characteristics to other vertebrate IL-2s, and may play a role in T cell development and differentiation.

Prostaglandin E2 Secreted by Thyroid Cancer Cells Contributes to Immune Escape Through the Suppression of Natural Killer (NK) Cell Cytotoxicity and NK Cell Differentiation

Natural killer (NK) cells play important roles in immune surveillance. However, the tumor microenvironment suppresses NK cell function and allows cancer cells to evade immune detection. In this study, we investigated whether the thyroid cancer cell microenvironment has this effect on NK cells. We found that prostaglandin (PG) E2 produced by thyroid cancer cells suppressed the cytolytic activity of NK cells by inhibiting the expression of the natural cytotoxicity receptors NKp44 and NKp30 and the death receptor tumor necrosis factor-related apoptosis-inducing ligand. PGE2 and cyclooxygenase-2 were highly expressed in thyroid cancer cells; moreover, anaplastic thyroid cancer cells released higher amounts of PGE2 than the papillary subtype, which was associated with suppression of NK cell-inducing nuclear factor-κB and mitogen-activated protein kinase/extracellular signal-regulated kinase pathways via PGE2 receptor (EP) 2 and EP4 expressed on the NK cell surface. In addition, PGE2 inhibited the functional maturation of NK cells and reduced their cytotoxicity against target cells. These results indicate that PGE2 promotes thyroid cancer progression by inhibiting NK cell maturation and cytotoxicity. Thus, therapeutic strategies that target PGE2 in thyroid cancer could potentiate the immune response and improve patient prognosis.

IL-15 and IFN-γ signal through the ERK pathway to inhibit HCV replication, independent of type I IFN signaling

Despite effective new treatments for Hepatitis C virus (HCV) infection, development of drug resistance, safety concerns and cost are remaining challenges. More importantly, there is no vaccine available against hepatitis C infection. Recent data suggest that there is a strong correlation between spontaneous HCV clearance and human NK cell function, particularly IFN-γ production. Further, IL-15 has innate antiviral activity and is also one of the main factors that activates NK cells to produce IFN-γ. To examine whether IL-15 and IFN-γ have direct antiviral activity against HCV, Huh7.5 cells were treated with either IFN-γ or IL-15 prior to HCV infection. Our data demonstrate that IFN-γ and IL-15 block HCV replication in vitro. Additionally, we show that IL-15 and IFN-γ do not induce anti-HCV effects through the type I interferon signaling pathway or nitric oxide (NO) production. Instead, IL-15 and IFN-γ provide protection against HCV via the ERK pathway. Treatment of Huh7.5 cells with a MEK/ERK inhibitor abrogated the anti-HCV effects of IL-15 and IFN-γ and overexpression of ERK1 prevented HCV replication compared to control transfection. Our in vitro data support the hypothesis that early production of IL-15 and activation of NK cells in the liver lead to control of HCV replication.

Revisiting colorectal cancer animal model - An improved metastatic model for distal rectosigmoid colon carcinoma

Colorectal cancer (CRC) is the second most frequent and fatal cancer in Western countries. Understanding its biology with different incidence along the colon and rectum, genetic profile and how these factors contribute to local/distant progression, has been hampered by the lack of a suitable CRC model. We report a reproducible model, using human CRC cell lines (CL) (WiDr, LS1034, C2BBe1) injected (1 × 10⁷ cells/animal) in RNU rats (n = 55) which underwent cecostomy and descending colostomy with mucosal-cutaneous fistula of the sigmoid colon. CL were characterized by immunohistochemistry: CK20, CDX2, P53, vimentin, Ki67, CD44, CD133, E-cadherin, β-catenin and CEA; cancer stem cells-immune system interaction was studied and tumor progression was assessed with nuclear medicine imaging (^99mTc-MIBI). Animals developed locally invasive tumors and with WiDr neural invasion was registered. Cancer stem cells were detected in WiDr (CD44 positive). All the cell lines stimulated the immune system, being WiDr the most aggressive. Imaging studies demonstrated tumor uptake. With this CRC model we can study the microenvironment role and tumor-stroma interactions. All CL developed primary disease, but only the WiDR established neural invasion which may represent a metastatic pathway. This model can help unveiling the underlying metastatic mechanisms, and ultimately test better therapeutic approaches for CRC.

NK cells of the oldest seniors represent constant and resistant to stimulation high expression of cellular protective proteins SIRT1 and HSP70

Background

Natural killer cells (NK cells) are cytotoxic lymphocytes of innate immunity that reveal some immunoregulatory properties, however, their role in the process of ageing is not completely understood. The study aimed to analyze the expression of proteins involved in cellular stress response: sirtuin 1 (SIRT1), heat shock protein 70 (HSP70) and manganese superoxide dismutase (SOD2) in human NK cells with reference to the process of ageing. Non-stimulated and stimulated with IL-2, LPS or PMA with ionomycin cells originated from peripheral blood samples of: seniors aged over 85 (‘the oldest’; n = 25; 88.5 ± 0.5 years, mean ± SEM), seniors aged under 85 (‘the old’; n = 30; 75.6 ± 0.9 years) and the young (n = 31; 20.9 ± 0.3 years). The relationships between the levels of expression of cellular protective proteins in the studied population were also analyzed. The concentrations of carbonyl groups and 8-isoprostanes, markers of oxidative stress, in both stimulated and non-stimulated cultured NK cells were measured to assess the level of the oxidative stress in the cells.

Results

The oldest seniors varied from the other age groups by significantly higher expression of SIRT1 and HSP70 both in non-stimulated and stimulated NK cells. These cells also appeared to be resistant to further stimulations with IL-2, LPS or PMA with ionomycin. Highly positive correlations between SIRT1 and intracellular HSP70 in both stimulated and non-stimulated NK cells were observed. SOD2 presented low expression in non-stimulated cells, whereas its sensitivity to stimulation increased with age of donors. High positive correlations between SOD2 and surface HSP70 were observed. We found that the markers of oxidative stress in NK cells did not change with ageing.

Conclusions

The oldest seniors revealed well developed adaptive stress response in NK cells with increased, constant levels of SIRT1 and intracellular HSP70. They presented also very high positive correlations between expression of these cellular protective proteins both in stimulated and non-stimulated cells. These phenomena may contribute to the long lifespan of this group of elderly. Interestingly, in NK cells SOD2 revealed a distinct role in cellular stress response since it showed sensitivity to stimulation increasing with age of participants. These observations provide novel data concerning the role of NK cells in the process of ageing.

Acquired Natural Killer Cell Dysfunction in the Tumor Microenvironment of Classic Hodgkin Lymphoma

An understanding of interactions within the tumor microenvironment (TME) of classic Hodgkin lymphoma (cHL) has helped pave the way to novel immunotherapies that have enabled dormant and tumor-tolerant immune cells to be reactivated. The immunosuppressive nature of the TME in cHL specifically inhibits the proliferation and activity of natural killer (NK) cells, which contributes to tumor immune-escape mechanisms. This deficiency of NK cells begins at the tumor site and progresses systemically in patients with advanced disease or adverse prognostic factors. Several facets of cHL account for this effect on NK cells. Locally, malignant Reed-Sternberg cells and cells from the TME express ligands for inhibitory receptors on NK cells, including HLA-E, HLA-G, and programmed death-ligand 1. The secretion of chemokines and cytokines, including soluble IL-2 receptor (sCD25), Transforming Growth Factor-β, IL-10, CXCL9, and CXCL10, mediates the systemic immunosuppression. This review also discusses the potential reversibility of quantitative and functional NK cell deficiencies in cHL that are likely to lead to novel treatments.

A possible mechanism of impaired NK cytotoxicity in cancer patients: Down-regulation of DAP10 by TGF-β1

Aims and background

Elevated TGF-β1 secretion and down-modulation of NKG2D underlies impaired NK cytotoxicity in cancer patients. However, the molecular mechanism of immunosuppression by TGF-β1 is not yet clarified.

Methods

IL-2-activated human NK cells were cultured with TGF-β1. Protein levels of NKG2D and DAP10 were examined by FACS or immunoblot analyses. Real-time RT-PCR was performed to quantify the transcription levels. MAPK inhibitors were used to investigate intracellular signaling.

Results

TGF-β1 down-regulated total and surface NKG2D, which was partially dependent on transcriptional regulation. TGF-β1 treatment of human NK cells resulted in significant changes in both transcriptional and translational levels of DAP10. Moreover, treatment with bafilomycin A1 or folimycin restored total NKG2D levels in TGF-β1-treated NK cells. The impaired NKG2D down-modulation by TGF-β1 was not associated with activation of the MAPK signaling pathway.

Conclusions

TGF-β1 down-modulates surface NKG2D expression by controlling the transcriptional and translational levels of DAP10.

Nanoparticle anchoring targets immune agonists to tumors enabling anti-cancer immunity without systemic toxicity

Immunostimulatory agents such as agonistic anti-CD137 and interleukin (IL)−2 generate effective anti-tumor immunity but also elicit serious toxicities, hampering their clinical application. Here we show that combination therapy with anti-CD137 and an IL-2-Fc fusion achieves significant initial anti-tumor activity, but also lethal immunotoxicity deriving from stimulation of circulating leukocytes. To overcome this toxicity, we demonstrate that anchoring IL-2 and anti-CD137 on the surface of liposomes allows these immune agonists to rapidly accumulate in tumors while lowering systemic exposure. In multiple tumor models, immunoliposome delivery achieves anti-tumor activity equivalent to free IL-2/anti-CD137 but with the complete absence of systemic toxicity. Immunoliposomes stimulated tumor infiltration by cytotoxic lymphocytes, cytokine production, and granzyme expression, demonstrating equivalent immunostimulatory effects to the free drugs in the local tumor microenvironment. Thus, surface-anchored particle delivery may provide a general approach to exploit the potent stimulatory activity of immune agonists without debilitating systemic toxicities.

Immunostimulatory agents used in cancer treatment often elicit serious toxicities, limiting their clinical application. Here, the authors show that the use of liposomes to intravenously deliver surface-anchored IL-2 and anti-CD137 proteins enables anti-cancer immunity and reduces the toxic side effects.

Exoenzyme T Plays a Pivotal Role in the IFN-γ Production after Pseudomonas Challenge in IL-12 Primed Natural Killer Cells

Pseudomonas aeruginosa (PA) expresses the type III secretion system (T3SS) and effector exoenzymes that interfere with intracellular pathways. Natural killer (NK) cells play a key role in antibacterial immunity and their activation is highly dependent on IL-12 produced by myeloid cells. We studied PA and NK cell interactions and the role of IL-12 using human peripheral blood mononuclear cells, sorted human NK cells, and a human NK cell line (NK92). We used a wild-type (WT) strain of PA (PAO1) or isogenic PA-deleted strains to delineate the role of T3SS and exoenzymes. Our hypotheses were tested in vivo in a PA-pneumonia mouse model. Human NK cells or NK92 cell line produced low levels of IFN-γ in response to PA without IL-12 stimulation, whereas PA significantly increased IFN-γ after IL-12 priming. The modulation of IFN-γ production by PA required bacteria-to-cell contact. Among T3SS effectors, exoenzyme T (ExoT) upregulates IFN-γ production and control ERK activation. In vivo, ExoT also increases IFN-γ levels and the percentage of IFN-γ⁺ NK cells in lungs during PA pneumonia, confirming in vitro data. In conclusion, our results suggest that T3SS could modulate the production of IFN-γ by NK cells after PA infection through ERK activation.

Chemical constituents from the fruits of Ligustrum japonicum and their inhibitory effects on T cell activation

A previously undescribed nor-dammarane, 3β,20,23-trihydroxy-24,25,26,27-tetranordammarane; three previously undescribed secoiridoid glycosides, ligujaponosides A-B, and iso-oleonuzhenide; and twenty three known compounds, were isolated from the fruits of Ligustrum japonicum Thunb. Their chemical structures were elucidated by extensive spectroscopic analyses, including 1D and 2D NMR, and HRMS. The isolated compounds were screened for immunosuppressive effects on T activated cells by evaluating interleukin-2 (IL-2) production. Among them, sesamin inhibited IL-2 production in Jurkat T cells with an IC50 value of 38 ± 2 μM. In addition, sesamin inhibited the phosphorylation of extracellular signal-regulated protein kinase (ERK), a member of the mitogen-activated protein kinase (MAPK) family, in phorbol 12-myristate 13-acetate (PMA)/A23187-stimulated T cells. Therefore, sesamin was demonstrated to inhibit T cell activation via regulation of MAPK phosphorylation pathway.

Cutting Edge: Murine NK Cells Degranulate and Retain Cytotoxic Function without Store-Operated Calcium Entry

Sustained Ca2+ signaling, known as store-operated calcium entry (SOCE), occurs downstream of immunoreceptor engagement and is critical for cytotoxic lymphocyte signaling and effector function. CD8+ T cells require sustained Ca2+ signaling for inflammatory cytokine production and the killing of target cells; however, much less is known about its role in NK cells. In this study, we use mice deficient in stromal interacting molecules 1 and 2, which are required for SOCE, to examine the contribution of sustained Ca2+ signaling to murine NK cell function. Surprisingly, we found that, although SOCE is required for NK cell IFN-γ production in an NFAT-dependent manner, NK cell degranulation/cytotoxicity and tumor rejection in vivo remained intact in the absence of sustained Ca2+ signaling. Our data suggest that mouse NK cells use different signaling mechanisms for cytotoxicity compared with other cytotoxic lymphocytes.

Correlation Between Natural Killer Cell Activity and Systemic Inflammatory Markers for Heterogeneous Cancer Patients Treated With Wheel Balance Cancer Therapy

Background and Objective: Natural killer (NK) cells are known to have an effect on the prevention of tumorigenesis for the initial cancer, as well as the metastatic cancer. For the past several years, the relationship between cancer and inflammation has been actively studied in preclinical and clinical settings, but there are no reports on alterations in and correlation for NK cell activity (NKA) and systemic inflammatory markers. Accordingly, this study aimed to measure correlation between NKA and the levels of other systemic inflammatory markers in patients with gastric, breast, and pancreatic cancer who received Wheel Balance Cancer Therapy (WBCT). Methods: Forty-two electronic charts of patients with gastric, breast, and pancreatic cancer treated with WBCT from February 1, 2015 to September 30, 2015, were reviewed retrospectively. These charts were statistically analyzed, looking for alterations of and correlation for NKA and the expressions of systemic inflammatory markers. Results: Patients with a NKA of under 300 pg/mL at admission showed significantly higher erythrocyte sedimentation rate (ESR) and neutrophil-to-lymphocyte ratio (NLR) values and decreasing NLR values due to WBCT than patients with an NKA greater than 300 pg/mL. As a result of the correlation analysis between NKA and the levels of the systemic inflammatory markers, NKA showed significant negative correlation with NLR, ESR, and fibrinogen values. Conclusions: Negative correlation was identified between NKA and NLR, NKA and ESR, and NKA and fibrinogen in patients with heterogeneous cancer patients.

Upregulation of thioredoxin-1 in activated human NK cells confers increased tolerance to oxidative stress

Adoptive transfer of immune cells, such as T lymphocytes and NK cells, has potential to control cancer growth. However, this can be counteracted by immune escape mechanisms within the tumor microenvironment, including those mediated by reactive oxygen species (ROS). Here, we determined the levels of anti-oxidant molecules in NK cells and their capacity to overcome ROS-induced immune suppression. We investigated the effect of H2O2 on resting NK cells, IL-2-activated NK cells and NK cells expanded by coculture with the K562 leukemia cell line genetically modified to express membrane-bound IL-15 and 4-1BB ligand (K562-mb15-41BBL). Expression of anti-oxidant and anti-apoptotic genes was evaluated by expression array, and protein levels of anti-oxidant molecules by Western blot. Activated NK cells, IL-2-activated NK cells and NK cells expanded by K562-mb15-41BBL were significantly more resistant to H2O2-induced cell death than resting NK. Thioredoxin-1 (TXN1) and peroxiredoxin-1 (PRDX1) were also up-regulated in activated NK cells. Moreover, H2O2-induced cell death after IL-2 activation was significantly induced in the presence of an anti-TXN1-neutralising antibody. Collectively, these data document that activated NK cells can resist to H2O2-induced cell death by up-regulation of TXN1.

IL-17C/IL-17RE Augments T Cell Function in Autoimmune Hepatitis

Autoimmune hepatitis is a worldwide health problem and significant cause of mortality. However, the disease etiology is largely unknown, which accounts for ineffective treatment and uncontrolled disease progression. In this study, we demonstrated the functional importance of the IL-17C/IL-17RE axis in Con A-induced hepatitis. Elevated IL-17C expression was detected in liver samples of both human and mouse autoimmune hepatitis. IL-17C, produced by hepatocytes, and its specific receptor IL-17RE on liver-resident T cells were both found to be required in Con A-induced liver damage. Mechanistically, IL-17C augmented the expression of IL-2 by intrahepatic CD4+ T cells to promote NK cell activation and liver damage. To our knowledge, our findings thus for the first time defined the indispensable role of IL-17C/IL-17RE in autoimmune hepatitis; this axis may serve as a novel drug target for the treatment of this disease.