TNFα Augments Cytokine-Induced NK Cell IFNγ Production through TNFR2

Alginate-gelatine hydrogel microspheres protect NK cell proliferation and cytotoxicity under hypoxic conditions

AIMS

This study aimed to encapsulate natural killer (NK) cells in a hydrogel to sustain their function within the hypoxic tumour microenvironments.

METHODS

An alginate-gelatine hydrogel was generated via electrospray technology. Hydrogel biocompatibility was assessed through cell counting kit-8 and Live/Dead assays to ascertain cell. Moreover, we analysed lactate dehydrogenase assays to evaluate the cytotoxicity against tumours and utilised RT-qPCR to analyse cytokine gene level.

RESULTS

Alginate and gelatine formed hydrogels with diameters ranging from 489.2 ± 23.0 μm, and the encapsulation efficiency was 34.07 ± 1.76%. Encapsulated NK cells exhibited robust proliferation and tumour-killing capabilities under normoxia and hypoxia. Furthermore, encapsulation provided a protective shield against cell viability under hypoxia. Importantly, tumour-killing cytotoxicity through cytokines upregulation such as granzyme B and interferon-gamma was preserved under hypoxia.

CONCLUSION

The encapsulation of NK cells not only safeguards their viability but also reinforces anticancer capacity, countering the inhibition of activation induced by hypoxia.

Absence of ATM leads to altered NK cell function in mice

Ataxia-telangiectasia (A-T) is a rare disorder caused by genetic defects of A-T mutated (ATM) kinase, a key regulator of stress response, and characterized by neurodegeneration, immunodeficiency, and high incidence of cancer. Here we investigated NK cells in a mouse model of A-T (Atm-/-) showing that they are strongly impaired at killing tumor cells due to a block of early signaling events. On the other hand, in Atm-/- littermates with thymic lymphoma NK cell cytotoxicity is enhanced as compared with ATM-proficient mice, possibly via tumor-produced TNF-α. Results also suggest that expansion of exhausted NKG2D+ NK cells in Atm-/- mice is driven by low-level expression of stress-inducible NKG2D ligands, whereas development of thymoma expressing the high-affinity MULT1 ligand is associated with NKG2D down-regulation on NK cells. These results expand our understanding of immunodeficiency in A-T and encourage exploring NK cell biology in A-T patients in the attempt to identify cancer predictive biomarkers and novel therapeutic targets.

Crosstalk Between NK Cell Receptors and Tumor Membrane Hsp70-Derived Peptide: A Combined Computational and Experimental Study

Natural killer (NK) cells are central components of the innate immunity system against cancers. Since tumor cells have evolved a series of mechanisms to escape from NK cells, developing methods for increasing the NK cell antitumor activity is of utmost importance. It is previously shown that an ex vivo stimulation of patient-derived NK cells with interleukin (IL)-2 and Hsp70-derived peptide TKD (TKDNNLLGRFELSG, aa450-461) results in a significant upregulation of activating receptors including CD94 and CD69 which triggers exhausted NK cells to target and kill malignant solid tumors expressing membrane Hsp70 (mHsp70). Considering that TKD binding to an activating receptor is the initial step in the cytolytic signaling cascade of NK cells, herein this interaction is studied by molecular docking and molecular dynamics simulation computational modeling. The in silico results showed a crucial role of the heterodimeric receptor CD94/NKG2A and CD94/NKG2C in the TKD interaction with NK cells. Antibody blocking and CRISPR/Cas9-mediated knockout studies verified the key function of CD94 in the TKD stimulation and activation of NK cells which is characterized by an increased cytotoxic capacity against mHsp70 positive tumor cells via enhanced production and release of lytic granules and pro-inflammatory cytokines.

Molecular mechanisms of tumour necrosis factor signalling via TNF receptor 1 and TNF receptor 2 in the tumour microenvironment

Tumour necrosis factor (TNF) is a primary mediator of inflammatory processes by facilitating cell death, immune cell activation and triggering of inflammation. In the cancer context, research has revealed TNF as a multifaceted cytokine that can be both pro- or anti-tumorigenic depending on what context is observed. We explore the plethora of ways that TNF and its receptors manipulate the functional and phenotypic characteristics in the tumour microenvironment (TME) on both tumour cells and immune cells, promoting either tumour elimination or progression. Here, we discuss the latest cutting-edge TNF-focused biologics currently in clinical translation that modifies the TME to derive greater immune responses and therapeutic outcomes, and further give perspectives on the future of targeting TNF in the context of cancer by emerging technological approaches.

Enhanced CT-based radiomics model to predict natural killer cell infiltration and clinical prognosis in non-small cell lung cancer

Background

Natural killer (NK) cells are crucial for tumor prognosis; however, their role in non-small-cell lung cancer (NSCLC) remains unclear. The current detection methods for NSCLC are inefficient and costly. Therefore, radiomics represent a promising alternative.

Methods

We analyzed the radiogenomics datasets to extract clinical, radiological, and transcriptome data. The effect of NK cells on the prognosis of NSCLC was assessed. Tumors were delineated using a 3D Slicer, and features were extracted using pyradiomics. A radiomics model was developed and validated using five-fold cross-validation. A nomogram model was constructed using the selected clinical variables and a radiomic score (RS). The CIBERSORTx database and gene set enrichment analysis were used to explore the correlations of NK cell infiltration and molecular mechanisms.

Results

Higher infiltration of NK cells was correlated with better overall survival (OS) (P = 0.002). The radiomic model showed an area under the curve of 0.731, with 0.726 post-validation. The RS differed significantly between high and low infiltration of NK cells (P < 0.01). The nomogram, using RS and clinical variables, effectively predicted 3-year OS. NK cell infiltration was correlated with the ICOS and BTLA genes (P < 0.001) and macrophage M0/M2 levels. The key pathways included TNF-α signaling via NF-κB and Wnt/β-catenin signaling.

Conclusions

Our radiomic model accurately predicted NK cell infiltration in NSCLC. Combined with clinical characteristics, it can predict the prognosis of patients with NSCLC. Bioinformatic analysis revealed the gene expression and pathways underlying NK cell infiltration in NSCLC.

TRAIL-dependent apoptosis of peritoneal mesothelial cells by NK cells promotes ovarian cancer invasion

A crucial requirement for metastasis formation in ovarian high-grade serous carcinoma (HGSC) is the disruption of the protective peritoneal mesothelium. Using co-culture systems of primary human cells, we discovered that tumor-associated NK cells induce TRAIL-dependent apoptosis in mesothelial cells via death receptors DR4 and DR5 upon encounter with activated T cells. Upregulation of TRAIL expression in NK cells concomitant with enhanced cytotoxicity toward mesothelial cells was driven predominantly by T-cell-derived TNFα, as shown by affinity proteomics-based analysis of the T cell secretome in conjunction with functional studies. Consistent with these findings, we detected apoptotic mesothelial cells in the peritoneal fluid of HGSC patients. In contrast to mesothelial cells, HGSC cells express negligible levels of both DR4 and DR5 and are TRAIL resistant, indicating cell-type-selective killing by NK cells. Our data point to a cooperative action of T and NK in breaching the mesothelial barrier in HGSC patients.

The TNFα/TNFR2 axis mediates natural killer cell proliferation by promoting aerobic glycolysis

Natural killer (NK) cells are predominant innate lymphocytes that initiate the early immune response during infection. NK cells undergo a metabolic switch to fuel augmented proliferation and activation following infection. Tumor necrosis factor-alpha (TNFα) is a well-known inflammatory cytokine that enhances NK cell function; however, the mechanism underlying NK cell proliferation in response to TNFα is not well established. Here, we demonstrated that upon infection/inflammation, NK cells upregulate the expression of TNF receptor 2 (TNFR2), which is associated with increased proliferation, metabolic activity, and effector function. Notably, IL-18 can induce TNFR2 expression in NK cells, augmenting their sensitivity toward TNFα. Mechanistically, TNFα-TNFR2 signaling upregulates the expression of CD25 (IL-2Rα) and nutrient transporters in NK cells, leading to a metabolic switch toward aerobic glycolysis. Transcriptomic analysis revealed significantly reduced expression levels of genes involved in cellular metabolism and proliferation in NK cells from TNFR2 KO mice. Accordingly, our data affirmed that genetic ablation of TNFR2 curtails CD25 upregulation and TNFα-induced glycolysis, leading to impaired NK cell proliferation and antiviral function during MCMV infection in vivo. Collectively, our results delineate the crucial role of the TNFα-TNFR2 axis in NK cell proliferation, glycolysis, and effector function.

Natural killer cells and their exosomes in viral infections and related therapeutic approaches: where are we?

Innate immunity is the first line of the host immune system to fight against infections. Natural killer cells are the innate immunity lymphocytes responsible for fighting against virus-infected and cancerous cells. They have various mechanisms to suppress viral infections. On the other hand, viruses have evolved to utilize different ways to evade NK cell-mediated responses. Viruses can balance the response by regulating the cytokine release pattern and changing the proportion of activating and inhibitory receptors on the surface of NK cells. Exosomes are a subtype of extracellular vesicles that are involved in intercellular communication. Most cell populations can release these nano-sized vesicles, and it was shown that these vesicles produce identical outcomes to the originating cell from which they are released. In recent years, the role of NK cell-derived exosomes in various diseases including viral infections has been highlighted, drawing attention to utilizing the therapeutic potential of these nanoparticles. In this article, the role of NK cells in various viral infections and the mechanisms used by viruses to evade these important immune system cells are initially examined. Subsequently, the role of NK cell exosomes in controlling various viral infections is discussed. Finally, the current position of these cells in the treatment of viral infections and the therapeutic potential of their exosomes are reviewed. Video Abstract.

Therapeutic potential of TNFR2 agonists: a mechanistic perspective

TNFR2 agonists have been investigated as potential therapies for inflammatory diseases due to their ability to activate and expand immunosuppressive CD4+Foxp3+ Treg cells and myeloid-derived suppressor cells (MDSCs). Despite TNFR2 being predominantly expressed in Treg cells at high levels, activated effector T cells also exhibit a certain degree of TNFR2 expression. Consequently, the role of TNFR2 signaling in coordinating immune or inflammatory responses under different pathological conditions is complex. In this review article, we analyze possible factors that may determine the therapeutic outcomes of TNFR2 agonism, including the levels of TNFR2 expression on different cell types, the biological properties of TNFR2 agonists, and disease status. Based on recent progress in the understanding of TNFR2 biology and the study of TNFR2 agonistic agents, we discuss the future direction of developing TNFR2 agonists as a therapeutic agents.

The macrophage infectivity potentiator of Trypanosoma cruzi induces innate IFN-γ and TNF-α production by human neonatal and adult blood cells through TLR2/1 and TLR4

We previously identified the recombinant (r) macrophage (M) infectivity (I) potentiator (P) of the protozoan parasite Trypanosoma cruzi (Tc) (rTcMIP) as an immuno-stimulatory protein that induces the release of IFN-γ, CCL2 and CCL3 by human cord blood cells. These cytokines and chemokines are important to direct a type 1 adaptive immune response. rTcMIP also increased the Ab response and favored the production of the Th1-related isotype IgG2a in mouse models of neonatal vaccination, indicating that rTcMIP could be used as a vaccine adjuvant to enhance T and B cell responses. In the present study, we used cord and adult blood cells, and isolated NK cells and human monocytes to investigate the pathways and to decipher the mechanism of action of the recombinant rTcMIP. We found that rTcMIP engaged TLR1/2 and TLR4 independently of CD14 and activated the MyD88, but not the TRIF, pathway to induce IFN-γ production by IL-15-primed NK cells, and TNF-α secretion by monocytes and myeloid dendritic cells. Our results also indicated that TNF-α boosted IFN-γ expression. Though cord blood cells displayed lower responses than adult cells, our results allow to consider rTcMIP as a potential pro-type 1 adjuvant that might be associated to vaccines administered in early life or later.

Infliximab Induction Lacks Efficacy and Increases BK Virus Infection in Deceased Donor Kidney Transplant Recipients: Results of the CTOT-19 Trial

BACKGROUND

Ischemia-reperfusion (IR) of a kidney transplant (KTx) upregulates TNF α production that amplifies allograft inflammation and may negatively affect transplant outcomes.

METHODS

We tested the effects of blocking TNF peri-KTx via a randomized, double-blind, placebo-controlled, 15-center, phase 2 clinical trial. A total of 225 primary transplant recipients of deceased-donor kidneys (KTx; 38.2% Black/African American, 44% White) were randomized to receive intravenous infliximab (IFX) 3 mg/kg or saline placebo (PLBO) initiated before kidney reperfusion. All patients received rabbit anti-thymocyte globulin induction and maintenance immunosuppression (IS) with tacrolimus, mycophenolate mofetil, and prednisone. The primary end point was the difference between groups in mean 24-month eGFR.

RESULTS

There was no difference in the primary end point of 24-month eGFR between IFX (52.45 ml/min per 1.73 m 2 ; 95% CI, 48.38 to 56.52) versus PLBO (57.35 ml/min per 1.73 m 2 ; 95% CI, 53.18 to 61.52; P =0.1). There were no significant differences between groups in rates of delayed graft function, biopsy-proven acute rejection (BPAR), development of de novo donor-specific antibodies, or graft loss/death. Immunosuppression did not differ, and day 7 post-KTx plasma analyses showed approximately ten-fold lower TNF ( P <0.001) in IFX versus PLBO. BK viremia requiring IS change occurred more frequently in IFX (28.9%) versus PLBO (13.4%; P =0.004), with a strong trend toward higher rates of BKV nephropathy in IFX (13.3%) versus PLBO (4.9%; P =0.06).

CONCLUSIONS

IFX induction therapy does not benefit recipients of kidney transplants from deceased donors on this IS regimen. Because the intervention unexpectedly increased rates of BK virus infections, our findings underscore the complexities of targeting peritransplant inflammation as a strategy to improve KTx outcomes.Clinical Trial registry name and registration number:clinicaltrials.gov (NCT02495077).

Down-regulation of IL-32γ expression reduces killing effect of natural killer cells on esophageal carcinoma cells

BACKGROUND

Interleukin (IL)-32γ is highly expressed in activated natural killer (NK) cells in esophageal cancer. However, it is not clear whether the expression level of IL-32γ in NK cells affects their killing effect on esophageal cancer cells.

AIM

To investigate the role of IL-32γ in the anti-tumor effect of NK cells in esophageal cancer.

METHODS

After transfecting NK-92 cells with shRNA targeting IL-32γ (shIL-32γ), the NK-92 cells were co-cultured with esophageal cancer cells EC9706 and TE-1, respectively. EC9706 and TE-1 cells were then collected; cell viability was measured by cell counting kit-8 (CCK-8) assay, cell proliferation was detected by 5-ethynyl-2'-deoxyuridine (EDU) assay, cell apoptosis was detected by flow cytometry, and the expression of apoptosis-related proteins B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X (Bax), cleaved cysteine-containing aspartate-specific proteases 3 (caspase 3), tumor necrosis factor receptor superfamily member 6 (FAS), death receptor 3 (DR3), and tumor necrosis factor receptor 2 (TNFR2) was detected by Western blot.

RESULTS

After IL-32γ deletion in NK-92 cells, the cell viability and the EDU positive cells in EC9706 and TE-1 cells in the co-culture system were increased (P < 0.01), the expression level of Bcl-2 was increased (P < 0.01), and the expression levels of Bax, cleaved-caspase 3, FAS, DR3, and TNFR2 were all decreased (P < 0.01).

CONCLUSION

Knockdown of IL-32γ attenuates the anti-tumor effect of NK-92 cells, which may be related to the inhibition of death receptor expression and caspase-3 activation in esophageal cancer cells.

The present and future of immunocytokines for cancer treatment

Monoclonal antibody (mAb) therapy has successfully been introduced as treatment of several lymphomas and leukemias. However, solid tumors reduce the efficacy of mAb therapy because of an immune-suppressive tumor micro-environment (TME), which hampers activation of effector immune cells. Pro-inflammatory cytokine therapy may counteract immune suppression in the TME and increase mAb efficacy, but untargeted pro-inflammatory cytokine therapy is limited by severe off-target toxicity and a short half-life of cytokines. Antibody-cytokine fusion proteins, also referred to as immunocytokines, provide a solution to either issue, as the antibody both acts as local delivery platform and increases half-life. The antibody can furthermore bridge local cytotoxic immune cells, like macrophages and natural killer cells with tumor cells, which can be eliminated after effector cells are activated via the cytokine. Currently, a variety of different antibody formats as well as a handful of cytokine payloads are used to generate immunocytokines. However, many potential formats and payloads are still left unexplored. In this review, we describe current antibody formats and cytokine moieties that are used for the development of immunocytokines, and highlight several immunocytokines in (pre-)clinical studies. Furthermore, potential future routes of development are proposed.

ILC1s control leukemia stem cell fate and limit development of AML

Type I innate lymphoid cells (ILC1) are critical regulators of inflammation and immunity in mammalian tissues. However, their function in cancer is mostly undefined. Here we show that a high density of ILC1s induces leukemia stem cell (LSC) apoptosis in mice. At a lower density, ILC1s prevent LSCs from differentiating into leukemia progenitors and promote their differentiation into non-leukemic cells, thus blocking the production of terminal myeloid blasts. All of these effects, which require ILC1s to produce interferon-γ after cell–cell contact with LSCs, converge to suppress leukemogenesis in vivo. Conversely, the anti-leukemia potential of ILC1s wanes when JAK-STAT or PI3K-AKT signaling is inhibited. The relevant anti-leukemic properties of ILC1s are also functional in healthy people and impaired in patients with acute myeloid leukemia (AML). Collectively, these findings identify ILC1s as anti-cancer immune cells that might be suitable for AML immunotherapy, and provide a potential strategy to treat AML and prevent relapse of the disease.

Tranexamic acid alters the immunophenotype of phagocytes after lower limb surgery

Background

Tranexamic acid (TXA) is an antifibrinolytic agent frequently used in elective surgery to reduce blood loss. We recently found it also acts as a potent immune-modulator in patients undergoing cardiac surgery.

Methods

Patients undergoing lower limb surgery were enrolled into the “Tranexamic Acid in Lower Limb Arthroplasty” (TALLAS) pilot study. The cellular immune response was characterised longitudinally pre- and post-operatively using full blood examination (FBE) and comprehensive immune cell phenotyping by flowcytometry. Red blood cells and platelets were determined in the FBE and levels of T cell cytokines and the plasmin-antiplasmin complex determined using ELISA.

Results

TXA administration increased the proportion of circulating CD141+ conventional dendritic cells (cDC) on post-operative day (POD) 3. It also reduced the expression of CD83 and TNFR2 on classical monocytes and levels of circulating IL-10 at the end of surgery (EOS) time point, whilst increasing the expression of CCR4 on natural killer (NK) cells at EOS, and reducing TNFR2 on POD-3 on NK cells. Red blood cells and platelets were decreased to a lower extent at POD-1 in the TXA group, representing reduced blood loss.

Conclusion

In this investigation we have extended our examination on the immunomodulatory effects of TXA in surgery by also characterising the end of surgery time point and including B cells and neutrophils in our immune analysis, elucidating new immunophenotypic changes in phagocytes as well as NK cells. This study enhances our understanding of TXA-mediated effects on the haemostatic and immune response in surgery, validating changes in important functional immune cell subsets in orthopaedic patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-022-00373-3.

Targeting TNFR2 in Cancer: All Roads Lead to Rome

TNF receptor 2 (TNFR2) has become one of the best potential immune checkpoints that might be targeted, mainly because of its vital role in tumor microenvironments (TMEs). Overexpression of TNFR2 in some tumor cells and essential function in immunosuppressive cells, especially regulatory T cells (Tregs), makes blocking TNFR2 an excellent strategy in cancer treatment; however, there is evidence showing that activating TNFR2 can also inhibit tumor progression in vivo. In this review, we will discuss drugs that block and activate TNFR2 under clinical trials or preclinical developments up till now. Meanwhile, we summarize and explore the possible mechanisms related to them.

Combined spinal and general anesthesia attenuate tumor promoting effects of surgery. An experimental animal study

Background

Radical prostatectomy, a standard management approach for localized Prostate Cancer (PC), may cause a stress response associated with immune modulating effects. Regional anesthesia was hypothesized to reduce the immune effects of surgery by minimizing the neuroendocrine surgical stress response, thus mitigating tumor cells dissemination. Our primary objective was to investigate whether the use of spinal blocks attenuates PC tumor cells dissemination on an animal model. We also assessed the number of circulating NK cells and the amount of inflammatory and anti-inflammatory cytokines.

Materials and methods

A subcutaneous tumor model, with PC-3M cell line transfected with a luciferase-producing gene (PC-3M-luc-C6) was used. After proper tumor establishment and before tumors became metastatic, animals were submitted to tumor excision surgeries under general or combined (general and spinal) anesthesia. A control group was only anesthetized with general anesthesia.

Results

The subcutaneous tumor model with PC-3M-luc-C6 cells was effective in causing distant metastasis after 35 days. The number of circulating tumor cells increased in animals that underwent surgery under general anesthesia alone compared to the group submitted to combined anesthesia. Interleukin 6 levels were different in all groups, with increase in the general anesthesia group.

Conclusion

Our results suggest that combination of spinal and general anesthesia may attenuate the suppression of innate tumor immunity and it might be related to a reduction in the neuroendocrine response to surgery.

Institutional protocol number

Animal Ethics Committee 1332/2019.

•

Regional anesthesia is related to a reduction in the neuroendocrine response to surgery.

•

Spinal anesthesia combined with general anesthesia modulates Circulating Tumor Cells and cytokines after tissue damage.

•

General anesthesia combined to spinal block could reduce cancer cells dissemination in the postoperative period.

Immunomodulatory functional foods and their molecular mechanisms

The immune system comprises a complex group of processes that provide defense against diverse pathogens. These defenses can be divided into innate and adaptive immunity, in which specific immune components converge to limit infections. In addition to genetic factors, aging, lifestyle, and environmental factors can influence immune function, potentially affecting the susceptibility of the host to disease-causing agents. Chemical compounds in certain foods have been shown to regulate signal transduction and cell phenotypes, ultimately impacting pathophysiology. Research has shown that the consumption of specific functional foods can stimulate the activity of immune cells, providing protection against cancer, viruses, and bacteria. Here, we review a number of functional foods reported to strengthen immunity, including ginseng, mushrooms, chlorella, and probiotics (Lactobacillus plantarum). We also discuss the molecular mechanisms involved in regulating the activity of various types of immune cells. Identifying immune-enhancing functional foods and understanding their mechanisms of action will support new approaches to maintain proper health and combat immunological diseases.

Evidence is building to support the idea that specific ‘functional foods’ can stimulate the activity of cells and signaling systems of the immune system to provide protection against cancer, viruses and bacteria. Sanguine Byun and colleagues at Yonsei University in Seoul, South Korea, review research into a range of functional foods, foods thought to have health benefits beyond their nutritional value. These include ginseng, mushrooms, the green algae called Chlorella and the probiotic bacteria Lactobacillus plantarum. They also consider individual components of foods such as poly-gamma-glutamate, a natural polymer made by bacteria. A wide body of research is revealing diverse molecular mechanisms through which biochemicals in functional foods can modulate different aspects of the immune system. These include effects on both non-specific innate immunity and adaptive immunity, which targets specific invading pathogens and diseased cells.

Parity-induced changes to mammary epithelial cells control NKT cell expansion and mammary oncogenesis

Pregnancy reprograms mammary epithelial cells (MECs) to control their responses to pregnancy hormone re-exposure and carcinoma progression. However, the influence of pregnancy on the mammary microenvironment is less clear. Here, we used single-cell RNA sequencing to profile the composition of epithelial and non-epithelial cells in mammary tissue from nulliparous and parous female mice. Our analysis indicates an expansion of γδ natural killer T-like immune cells (NKTs) following pregnancy and upregulation of immune signaling molecules in post-pregnancy MECs. We show that expansion of NKTs following pregnancy is due to elevated expression of the antigen-presenting molecule CD1d on MECs. Loss of CD1d expression on post-pregnancy MECs, or overall lack of activated NKTs, results in mammary oncogenesis. Collectively, our findings illustrate how pregnancy-induced changes modulate the communication between MECs and the immune microenvironment and establish a causal link between pregnancy, the immune microenvironment, and mammary oncogenesis.

Altered expression of immune factors in sevenband grouper, Hyporthodus septemfasciatus following nervous necrosis virus challenge at optimal and suboptimal temperatures

The nervous necrosis virus (NNV) infection is generally observed in aquafarms when the seawater temperature is higher than 24 °C and the fishes seem to be refractory to disease at suboptimal temperatures below 20 °C suggesting a role of thermoregulation in NNV pathogenesis. The present study profiled the temperature-dependent regulation of cytokines (TNF-α, IL-1β and IFN-γ), innate antiviral factors (IFN-1, Mx, ISG-15), adaptive immune factors (CD-4, CD-8, IgM), signaling regulators (SOCS-1, SOCS-3), transcription factors (STAT-1, STAT-3) and microglial and NCC/NK specific cell markers (TMEM-119 and NCCRP-1) during NNV challenge in seven-band grouper, Hyporthodus septemfasciatus. The co-habitation challenge at 17 °C with showed a sustained expression of proinflammatory cytokines and following rechallenge with a dose of 10⁴ TCID₅₀/100μL/fish at optimal temperature, the survivors also exhibited a stable expression of immune factors. The 100% survival following the challenge at sub-optimal (17 °C) and rechallenge at optimal (25 °C) was due to the stable and sustained activation of the immune response. However, at 25 °C, the rechallenge displayed a priming effect with hyperactivation of the immune system evident from the immune gene expression profile. The mortality pattern observed is co-related with the cytokine storm as is evident from the gene expression profile. Whereas, neither of the adaptive immune markers was suggestive of humoral immune response in the 17 °C groups. Also, the data suggest a possible role of NK cell and microglia in mediating antiviral immune response following infection in the brain at different temperatures, where, former is beneficial in restricting viral infection with higher host tolerance.

COVID-19 Specific Immune Markers Revealed by Single Cell Phenotypic Profiling

COVID-19 is a viral infection, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and characterized by a complex inflammatory process and clinical immunophenotypes. Nowadays, several alterations of immune response within the respiratory tracts as well as at the level of the peripheral blood have been well documented. Nonetheless, their effects on COVID-19-related cell heterogeneity and disease progression are less defined. Here, we performed a single-cell RNA sequencing of about 400 transcripts relevant to immune cell function including surface markers, in mononuclear cells (PBMCs) from the peripheral blood of 50 subjects, infected with SARS-CoV-2 at the diagnosis and 27 healthy blood donors as control. We found that patients with COVID-19 exhibited an increase in COVID-specific surface markers in different subsets of immune cell composition. Interestingly, the expression of cell receptors, such as IFNGR1 and CXCR4, was reduced in response to the viral infection and associated with the inhibition of the related signaling pathways and immune functions. These results highlight novel immunoreceptors, selectively expressed in COVID-19 patients, which affect the immune functionality and are correlated with clinical outcomes.

TNFα and Immune Checkpoint Inhibition: Friend or Foe for Lung Cancer?

Tumor necrosis factor-alpha (TNFα) can bind two distinct receptors (TNFR1/2). The transmembrane form (tmTNFα) preferentially binds to TNFR2. Upon tmTNFα cleavage by the TNF-alpha-converting enzyme (TACE), its soluble (sTNFα) form is released with higher affinity for TNFR1. This assortment empowers TNFα with a plethora of opposing roles in the processes of tumor cell survival (and apoptosis) and anti-tumor immune stimulation (and suppression), in addition to angiogenesis and metastases. Its functions and biomarker potential to predict cancer progression and response to immunotherapy are reviewed here, with a focus on lung cancer. By mining existing sequencing data, we further demonstrate that the expression levels of TNF and TACE are significantly decreased in lung adenocarcinoma patients, while the TNFR1/TNFR2 balance are increased. We conclude that the biomarker potential of TNFα alone will most likely not provide conclusive findings, but that TACE could have a key role along with the delicate balance of sTNFα/tmTNFα as well as TNFR1/TNFR2, hence stressing the importance of more research into the potential of rationalized treatments that combine TNFα pathway modulators with immunotherapy for lung cancer patients.

Interferon-γ: teammate or opponent in the tumour microenvironment?

Cancer immunotherapy offers substantive benefit to patients with various tumour types, in some cases leading to complete tumour clearance. However, many patients do not respond to immunotherapy, galvanizing the field to define the mechanisms of pre-existing and acquired resistance. Interferon-γ (IFNγ) is a cytokine that has both protumour and antitumour activities, suggesting that it may serve as a nexus for responsiveness to immunotherapy. Many cancer immunotherapies and chemotherapies induce IFNγ production by various cell types, including activated T cells and natural killer cells. Patients resistant to these therapies commonly have molecular aberrations in the IFNγ signalling pathway or express resistance molecules driven by IFNγ. Given that all nucleated cells can respond to IFNγ, the functional consequences of IFNγ production need to be carefully dissected on a cell-by-cell basis. Here, we review the cells that produce IFNγ and the different effects of IFNγ in the tumour microenvironment, highlighting the pleiotropic nature of this multifunctional and abundant cytokine.

TNFR2: Role in Cancer Immunology and Immunotherapy

Immune checkpoint inhibitors (ICIs), including anti-CTLA-4 (cytotoxic T lymphocyte antigen-4) and anti-PD-1/PD-L1 (programmed death-1/programmed death-ligand 1), represent a turning point in the cancer immunotherapy. However, only a minor fraction of patients could derive benefit from such therapy. Therefore, new strategies targeting additional immune regulatory mechanisms are urgently needed. CD4⁺Foxp3⁺ regulatory T cells (Tregs) represent a major cellular mechanism in cancer immune evasion. There is compelling evidence that tumor necrosis factor (TNF) receptor type II (TNFR2) plays a decisive role in the activation and expansion of Tregs and other types of immunosuppressive cells such as myeloid-derived suppressor cells (MDSCs). Furthermore, TNFR2 is also expressed by some tumor cells. Emerging experimental evidence indicates that TNFR2 may be a therapeutic target to enhance naturally occurring or immunotherapeutic-triggered anti-tumor immune responses. In this article, we discuss recent advances in the understanding of the mechanistic basis underlying the Treg-boosting effect of TNFR2. The role of TNFR2-expressing highly suppressive Tregs in tumor immune evasion and their possible contribution to the non-responsiveness to checkpoint treatment are analyzed. Moreover, the role of TNFR2 expression on tumor cells and the impact of TNFR2 signaling on other types of cells that shape the immunological landscape in the tumor microenvironment, such as MDSCs, MSCs, ECs, EPCs, CD8⁺ CTLs, and NK cells, are also discussed. The reports revealing the effect of TNFR2-targeting pharmacological agents in the experimental cancer immunotherapy are summarized. We also discuss the potential opportunities and challenges for TNFR2-targeting immunotherapy.

Cytokines Orchestrating the Natural Killer-Myeloid Cell Crosstalk in the Tumor Microenvironment: Implications for Natural Killer Cell-Based Cancer Immunotherapy

Natural killer (NK) cells are endowed with germline-encoded receptors that enable them to detect and kill malignant cells without prior priming. Over the years, overwhelming evidence has identified an essential role for NK cells in tumor immune surveillance. More recently, clinical trials have also highlighted their potential in therapeutic settings. Yet, data show that NK cells can be dysregulated within the tumor microenvironment (TME), rendering them ineffective in eradicating the cancer cells. This has been attributed to immune suppressive factors, including the tumor cells per se, stromal cells, regulatory T cells, and soluble factors such as reactive oxygen species and cytokines. However, the TME also hosts myeloid cells such as dendritic cells, macrophages, neutrophils, and myeloid-derived suppressor cells that influence NK cell function. Although the NK-myeloid cell crosstalk can promote anti-tumor responses, myeloid cells in the TME often dysregulate NK cells via direct cell-to-cell interactions down-regulating key NK cell receptors, depletion of nutrients and growth factors required for NK cell growth, and secretion of metabolites, chemokines and cytokines that ultimately alter NK cell trafficking, survival, and cytotoxicity. Here, we review the complex functions of myeloid-derived cytokines in both supporting and suppressing NK cells in the TME and how NK cell-derived cytokines can influence myeloid subsets. We discuss challenges related to these interactions in unleashing the full potential of endogenous and adoptively infused NK cells. Finally, we present strategies aiming at improving NK cell-based cancer immunotherapies via pathways that are involved in the NK-myeloid cell crosstalk in the TME.

Chlamydia psittaci-Infected Dendritic Cells Communicate with NK Cells via Exosomes To Activate Antibacterial Immunity

Dendritic cells (DCs) and natural killer (NK) cells are critically involved in the early response against various bacterial microbes. Functional activation of infected DCs and NK cell-mediated gamma interferon (IFN-γ) secretion essentially contribute to the protective immunity against Chlamydia How DCs and NK cells cooperate during the antichlamydial response is not fully understood. Therefore, in the present study, we investigated the functional interplay between Chlamydia-infected DCs and NK cells. Our biochemical and cell biological experiments show that Chlamydia psittaci-infected DCs display enhanced exosome release. We find that such extracellular vesicles (referred to as dexosomes) do not contain infectious bacterial material but strongly induce IFN-γ production by NK cells. This directly affects C. psittaci growth in infected target cells. Furthermore, NK cell-released IFN-γ in cooperation with tumor necrosis factor alpha (TNF-α) and/or dexosomes augments apoptosis of both noninfected and infected epithelial cells. Thus, the combined effect of dexosomes and proinflammatory cytokines restricts C. psittaci growth and attenuates bacterial subversion of apoptotic host cell death. In conclusion, this provides new insights into the functional cooperation between DCs, dexosomes, and NK cells in the early steps of antichlamydial defense.

TNFR2 signaling modulates immunity after allogeneic hematopoietic cell transplantation

Tumor necrosis factor-α (TNF-α) signaling through TNF receptor 2 (TNFR2) plays a complex immune regulatory role in allogeneic hematopoietic cell transplantation (HCT). TNF-α is rapidly released in the circulation after the conditioning regimen with chemotherapy and/or radiotherapy. It activates the function of donor alloreactive T cells and donor Natural Killer cells and promotes graft versus tumor effects. However, donor alloreactive T cells also attack host tissues and cause graft versus host disease (GVHD), a life-threatening complication of HCT. Indeed, anti-TNF-α therapy has been used to treat steroid-refractory GVHD. Recent studies have highlighted another role for TNFR2 signaling, as it enhances the function of immune cells with suppressive properties, in particular CD4⁺Foxp3⁺ regulatory T cells (Tregs). Various clinical trials are employing Treg-based treatments to prevent or treat GVHD. The present review will discuss the effects of TNFR2 signaling in the setting of allogeneic HCT, the implications for the use of anti-TNF-α therapy to treat GVHD and the clinical perspectives of strategies that specifically target this pathway.

FcγRIIIa-dependent IFN-γ release in whole blood assay is predictive of therapeutic IgG1 antibodies safety

Immunomodulatory monoclonal IgG1 antibodies developed for cancer and autoimmune disease have an inherent risk of systemic release of pro-inflammatory cytokines. In vitro cytokine release assays are currently used to predict cytokine release syndrome (CRS) risk, but the validation of these preclinical tools suffers from the limited number of characterized CRS-inducing IgG1 antibodies and the poor understanding of the mechanisms regulating cytokine release. Here, we incubated human whole blood from naïve healthy volunteers with four monoclonal IgG1 antibodies with different proven or predicted capacity to elicit CRS in clinic and measured cytokine release using a multiplex assay. We found that, in contrast to anti-CD52 antibodies (Campath-1H homolog) that elicited high level of multiple inflammatory cytokines from human blood cells in vitro, other IgG1 antibodies with CRS-inducing potential consistently induced release of a single tested cytokine, interferon (IFN)-γ, with a smaller magnitude than Campath. IFN-γ expression was observed as early as 2-4 h after incubation, mediated by natural killer cells, and dependent upon tumor necrosis factor and FcγRIII. Importantly, the magnitude of the IFN-γ response elicited by IgG1 antibodies with CRS-inducing potential was determined by donor FcγRIIIa-V158F polymorphism. Overall, our results highlight the importance of FcγRIIIa-dependent IFN-γ release in preclinical cytokine release assay for the prediction of CRS risk associated with therapeutic IgG1 antibodies.

TNFR2/BIRC3-TRAF1 signaling pathway as a novel NK cell immune checkpoint in cancer

Natural Killer (NK) cells control metastatic dissemination of murine tumors and are an important prognostic factor in several human malignancies. However, tumor cells hijack many of the NK cell functional features compromising their tumoricidal activity. Here, we show a deleterious role of the TNFα/TNFR2/BIRC3/TRAF1 signaling cascade in NK cells from the tumor microenvironment (TME). TNFα induces BIRC3/cIAP2 transcripts and reduces NKp46/NCR1 transcription and surface expression on NK cells, promoting metastases dissemination in mice and poor prognosis in GIST patients. NKp30 engagement, by promoting the release of TNFα, also contributes to BIRC3 upregulation, and more so in patients expressing predominantly NKp30C isoforms. These findings reveal that in the absence of IL-12 or a Th1-geared TME, TNFα can be considered as a negative regulatory cytokine for innate effectors.

Natural killer cell activation contributes to hepatitis B viral control in a mouse model

The roles of CD4 + T cells and CD8 + T cells in hepatitis B virus (HBV) infection have been well documented. However, the role of innate immunity in HBV infection remains obscure. Here we examined the effect of activation of innate immunity by polyinosinic: polycytidylic acid (PolyI:C) on HBV infection. A chronic HBV replication mouse model was established by hydrodynamical injection of pAAV/HBV1.2 plasmid into C57BL/6 mice. We found that HBV did not seem to induce an active NK-cell response in the mouse model. Early PolyI:C treatment markedly decreased serum HBV levels and led to HBV clearance. Following PolyI:C injection, NK cells were activated and accumulated in the liver. Depletion of NK cells markedly attenuated the anti-HBV activity of PolyI:C. Moreover, we found that IFN-γ production from NK cells was essential for the antiviral effect of PolyI:C in the model. Importantly, activation of NK cells by PolyI:C could also lead to HBV suppression in HBV-tolerant mice and HBV-transgenic mice. These results suggest that activated NK cells might suppress HBV and contribute to HBV clearance during natural HBV infection. In addition, therapeutic activation of NK cells may represent a new strategy for the treatment of chronic HBV infection.