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The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has led to global morbidity and mortality. Some patients fully recover from COVID-19, whereas around 45% subjects suffer from various persistent symptoms (fatigue, cognitive impairment, impaired thermoregulation, skin diseases, etc.) for at least four months after SARS-CoV-2 infection regardless of disease severity. Such persistent post-infection effects are known as long-COVID, post-acute effects of COVID-19, or post-COVID state. SARS-CoV-2 infection is accompanied by damage to the innate immune system. Considering the role of natural killer cells and the activation of the complement system in COVID-19 as well as the regulatory properties related to CD46 and its potential involvement in cell virus entry, we found necessary to study immune system parameters associated with impairment of these innate immune cues on various leukocyte subpopulations in post-COVID patients. We studied 92 immune system parameters, including: pan-leukocyte markers for gated lymphocytes, phenotyping of T cells, T-helper inducers, cytotoxic T-lymphocytes, NK- and TNK-cells, T-regulatory cells/suppressors, B-lymphocytes, including B-memory cells, activated helpers, early activation of lymphocytes, activated T-lymphocytes, and late lymphocyte activation markers. Levels of total IgM, IgG, IgA, specific IgM, IgG to coronavirus COVID-19, C1-inhibitor, C3a, and C5a complement components were measured by enzyme immunoassay using Multiscan FC Thermoscientific enzyme immunoassay analyzer (China) and Vector Best reagent kits (Russia). A complete blood count was conducted to study 25 parameters: leukocyte, erythrocyte, and platelet hematopoietic lineages as well as the quantitative and qualitative composition of hematopoietic lineages. Our study results showed that in some patients, six months after suffering from COVID-19, there was a decrease in the level of NK cells (48%) and CD46+pan-leukocyte marker cells (64.5%). A decrease in NK cell levels was accompanied by increased level of total T- and B-lymphocytes, and altered platelet and erythroid hematopoietic lineages. In patients with reduced CD46 expression on T-lymphocytes, both their total count and NK cell count were significantly reduced. Our data also suggest that CD46 might be potentially involved in development of SARS-CoV-2 infection and the post-COVID state. Thus, in 50–65% of patients who have experienced SARS-CoV-2 infection, damage to the innate immune system persists after six months being accompanied by impaired erythroid and platelet hematopoietic lineages. The data obtained indicate a need for using immunocorrective therapy in such patients.

Hepatocellular carcinoma (HCC) is among the most lethal cancer types despite great advancement in overall survival of the patients over the last decades. Surgical resection or partial hepatectomy has been approved as the curative treatment for early-stage HCC patients however only up to 30% of them are eligible for the procedures. Natural killer (NK) cells are cytotoxic lymphocytes recognized for killing virally infected cells and improving immune functions for defending the body against malignant cells. Although autologous NK cells failed to demonstrate significant clinical benefit, transfer of allogeneic adoptive NK cells arises as a promising approach for the treatment of solid tumors. The immunosuppressive tumor microenvironment and inadequate homing efficiency of NK cells to tumors can inhibit adoptive transfer immunotherapy (ATI) efficacy. However, potential of the NK cells is challenged by the transfection efficiency. The local ablation techniques that employ thermal or chemical energy have been investigated for the destruction of solid tumors for three decades and demonstrated promising benefits for individuals not eligible for surgical resection or partial hepatectomy. Irreversible electroporation (IRE) is one of the most recent minimally invasive ablation methods that destruct the cell within the targeted region through non-thermal energy. IRE destroys the tumor cell membrane by delivering high-frequency electrical energy in short pulses and overcomes tumor immunosuppression. The previous studies demonstrated that IRE can induce immune changes which can facilitate activation of specific immune responses and improve transfection efficiency. In this review paper, we have discussed the mechanism of NK cell immunotherapy and IRE ablation methods for the treatment of HCC patients and the combinatorial benefits of NK cell immunotherapy and IRE ablation.

Cellular metabolism is essential for the correct function of immune system cells, including Natural Killer cells (NK). These cells depend on energy to carry out their effector functions, especially in the early stages of viral infection. NK cells participate in the innate immune response against viruses and tumors. Their main functions are cytotoxicity and cytokine production. Metabolic changes can impact intracellular signals, molecule production, secretion, and cell activation which is essential as the first line of immune defense. Metabolic variations in different immune cells in response to a tumor or pathogen infection have been described; however, little is known about NK cell metabolism in the context of viral infection. This review summarizes the activation-specific metabolic changes in NK cells, the immunometabolism of NK cells during early, late, and chronic antiviral responses, and the metabolic alterations in NK cells in SARS-CoV2 infection. The modulation points of these metabolic routes are also discussed to explore potential new immunotherapies against viral infections. [ABSTRACT FROM AUTHOR]

Endometriosis is a chronic inflammatory disorder, characterized by the presence of endometrial cells outside the uterine cavity. An increasing number of studies correlate the immune system with endometriosis, particularly NK receptors (NKR), which have been suggested to play an essential role in the pathogenesis of the disease. This systematic review aims to enlighten the role of NKR in endometriosis. A literature search was performed independently by two reviewers, to identify studies assessing the role of NKR in endometriosis. In total, 18 studies were included. Endometriosis pathogenesis seems to be marked by the overexpression of NK inhibitor receptors (KIRS), namely, CD158a+, KIR2DL1, CD94/NKG2A, PD-1, NKB1, and EB6, and inhibiting ligands such as PD-L1, HLA-E, HLA-G, and HLA-I. Concurrently, there is a decrease in NK-activating receptors and natural cytotoxicity receptors (NCRs), such as NKp46, NKp30, and NKG2D. The immune shift from NK surveillance to NK suppression is also apparent in the greater relative number of ITIM domains compared with ITAM domains in NKRs. In conclusion, NK receptor activity seems to dictate the immunocompetency of women to clear endometriotic cells from the peritoneal cavity. Future research could explore NKRs as therapeutic targets, such as that which is now well established in cancer therapy through immunotherapy. [ABSTRACT FROM AUTHOR]

Natural killer (NK) cell-based adoptive immunotherapy in leukemia patients is an emerging field of interest based on clinical evidence of efficacy and safety. Elderly acute myeloid leukemia (AML) patients have been successfully treated with NK cells from HLA-haploidentical donors, especially when high amounts of alloreactive NK cells were infused. The aim of this study was comparing two approaches to define the size of alloreactive NK cells in haploidentical donors for AML patients recruited in two clinical trials with the acronym “NK-AML” (NCT03955848), and “MRD-NK”. The standard methodology was based on the frequency of NK cell clones capable of lysing the related patient-derived cells. The alternative approach consisted of the phenotypic identification of freshly derived NK cells expressing, as inhibitory receptors, only the inhibitory KIR(s) specific for the mismatched KIR-Ligand(s) (HLA-C1, HLA-C2, HLA-Bw4). However, in KIR2DS2+ donors and HLA-C1+ patients, the unavailability of reagents staining only the inhibitory counterpart (KIR2DL2/L3) may lead to an underestimated identification of the alloreactive NK cell subset. Conversely, in the case of HLA-C1 mismatch, the alloreactive NK cell subset could be overestimated due to the ability of KIR2DL2/L3 to recognize with low-affinity also HLA-C2. Especially in this context, the additional exclusion of LIR1-expressing cells might be relevant to refine the size of the alloreactive NK cell subset. We could also associate degranulation assays, using as effector cells IL-2 activated donor peripheral blood mononuclear cells (PBMC) or NK cells upon co-culture with the related patient target cells. The donor alloreactive NK cell subset always displayed the highest functional activity, confirming its identification accuracy by flow cytometry. Despite the phenotypic limitations and considering the proposed corrective actions, a good correlation was shown by the comparison of the two investigated approaches. In addition, the characterization of receptor expression on a fraction of NK cell clones revealed expected but also few unexpected patterns. Thus, in most instances, the quantification of phenotypically defined alloreactive NK cells from PBMC can provide data similar to the analysis of lytic clones, with several advantages, such as a shorter time to achieve the results and, perhaps, higher reproducibility/feasibility in many laboratories.

Cellular metabolism is essential for the correct function of immune system cells, including Natural Killer cells (NK). These cells depend on energy to carry out their effector functions, especially in the early stages of viral infection. NK cells participate in the innate immune response against viruses and tumors. Their main functions are cytotoxicity and cytokine production. Metabolic changes can impact intracellular signals, molecule production, secretion, and cell activation which is essential as the first line of immune defense. Metabolic variations in different immune cells in response to a tumor or pathogen infection have been described; however, little is known about NK cell metabolism in the context of viral infection. This review summarizes the activation-specific metabolic changes in NK cells, the immunometabolism of NK cells during early, late, and chronic antiviral responses, and the metabolic alterations in NK cells in SARS-CoV2 infection. The modulation points of these metabolic routes are also discussed to explore potential new immunotherapies against viral infections.

Human natural killer (NK) cells in lymphoid tissues can be categorized into three subsets: CD56brightCD16+, CD56dimCD16+ and CD69+CXCR6+ lymphoid tissue-resident (lt)NK cells. How the three subsets are functionally and developmentally related is currently unknown. Therefore, we performed single-cell RNA sequencing combined with oligonucleotide-conjugated antibodies against CD56, CXCR6, CD117 and CD34 on fresh bone marrow NK cells. A minor CD56dimGzmK+ subset was identified that shared features with CD56bright and CD56dimGzmK-NK cells based on transcriptome, phenotype (NKG2AhighCD16lowKLRG1highTIGIThigh) and functional analysis in bone marrow and blood, supportive for an intermediate subset. Pseudotime analysis positioned CD56bright, CD56dimGzmK+ and CD56dimGzmK- cells in one differentiation trajectory, while ltNK cells were developmentally separated. Integrative analysis with bone marrow cells from the Human Cell Atlas did not demonstrate a developmental connection between CD34+ progenitor and NK cells, suggesting absence of early NK cell stages in bone marrow. In conclusion, single-cell transcriptomics provide new insights on development and differentiation of human NK cells. [ABSTRACT FROM AUTHOR]

Human natural killer (NK) cells in lymphoid tissues can be categorized into three subsets: CD56brightCD16+, CD56dimCD16+ and CD69+CXCR6+ lymphoid tissue-resident (lt)NK cells. How the three subsets are functionally and developmentally related is currently unknown. Therefore, we performed single-cell RNA sequencing combined with oligonucleotide-conjugated antibodies against CD56, CXCR6, CD117 and CD34 on fresh bone marrow NK cells. A minor CD56dimGzmK+ subset was identified that shared features with CD56bright and CD56dimGzmK- NK cells based on transcriptome, phenotype (NKG2AhighCD16lowKLRG1highTIGIThigh) and functional analysis in bone marrow and blood, supportive for an intermediate subset. Pseudotime analysis positioned CD56bright, CD56dimGzmK+ and CD56dimGzmK- cells in one differentiation trajectory, while ltNK cells were developmentally separated. Integrative analysis with bone marrow cells from the Human Cell Atlas did not demonstrate a developmental connection between CD34+ progenitor and NK cells, suggesting absence of early NK cell stages in bone marrow. In conclusion, single-cell transcriptomics provide new insights on development and differentiation of human NK cells.

Introduction: With current goals of increased space exploration and travel to Mars, there has been great interest in understanding the long-term effects of high atomic number, high energy (HZE) ion exposure on various organ systems and the immune system. Little is known about late effects on the immune system after HZE exposure. Therefore, our objective was to determine how natural killer (NK) cell populations were affected in geriatric mice that were exposed to HZE particles during middle-age, thereby representing elderly retired astronauts that undertook deep space missions.Methods: 10 month old male CBA/CaJ mice were whole-body irradiated: sham (control); 150-cGy gamma-rays (delivered in 1 fraction); 40-cGy 1-GeV/nu 28Si14+ ions (delivered in 3 fractions); 40-cGy 1-GeV/nu 16O8+ ions (1 fraction); and 40-cGy 1-GeV/nu 16O8+ ions (3 fractions). The mice were sacrificed 1–1.5 yr post-exposure, and the spleens harvested. Splenocyte effector (E) cells were harvested and added to 51Cr-labeled Yac-1 target (T) cells in E:T ratios of 12:1, 25:1, 50:1, and 100:1. NK cytotoxicity was measured with 51Cr release. In addition, 2 million splenocytes were aliquoted and stained with a seven-antibody cocktail, and flow cytometry was used to determine the percentage of NK, B lymphocytes, and T lymphocytes in the splenocyte population.Results: Mice exposed to either a single fraction of 150-cGy gamma rays or 40-cGy 16O8+ ions in 3 fractions were found to have significant decreases in NK cytotoxicity of approximately 30% and 25%, respectively. No significant differences were observed in NK cytotoxicity for 40-cGy 16O8+ ions delivered in 1 fraction, or 40-cGy 28Si14+ ions delivered in 3 fractions. No significant differences were observed in the percentage of spleen cells that were NK (%NK) amongst the groups.Conclusion: Fractionated HZE ion exposure has the potential to affect the innate arm of the immune system long after exposure, leading to decreases in NK cell function. Therefore, protective countermeasures may need to be considered to decrease the risk of reduced long-term immune function in elderly retired astronauts that undertook deep space missions.

Lymphatic filariasis and onchocerciasis are major neglected tropical diseases affecting over 90 million people worldwide with painful and profoundly disfiguring pathologies (such as lymphoedema or blindness). Type 2 inflammation is a hallmark of filarial nematode tissue infection and is implicated both in eosinophil dependent immunity and lymphatic or ocular immunopathologies. Type-2 innate lymphoid cells (ILC2) are known to play an important role in the initiation of type 2 inflammation in helminth infection. We therefore tracked comparative IL-12Rβ2+ ILC1, ST2+ ILC2 and NKp46+ natural killer (NK) innate lymphoid cell population expansions during Brugia malayi experimental peritoneal filarial infections using either immunocompetent or immunodeficient mice. In immunocompetent BALB/c animals, NKp46+ NK cells rapidly expanded representing over 90% of the ILC population in the first week of infection, whereas, surprisingly, ST2+ ILC2 failed to expand. NKp46+ NK cell expansions were confirmed in RAG2 deficient mice lacking adaptive immunity. Ablation of the NKp46+ NK cell compartment in RAG2 common gamma chain (gc) mice led to increased susceptibility to chronic adult B. malayi infection. This data was recapitulated using an Onchocerca ochengi male worm peritoneal implant model. When NKp46+ NK cells were depleted in RAG2 deficient mice using anti-NKp46 or asialo GM1 antibody injections over the first five weeks of B. malayi infection, susceptibility to adult B. malayi infection was significantly increased by 2-3 fold with concomitant impairment in eosinophil or neutrophil recruitments. Finally, we demonstrate that in RAG2 deficient mice, drug clearance of a primary adult B. malayi infection followed by challenge infection leads to resistance against early larval B. malayi establishment. This innate resistance is associated with bolstered NK and eosinophils whereby NKp46+ NK cells express markers of memory-like/ enhanced activation (increased expression of interferon gamma and Ly6C). Our data promotes a novel functional role for NKp46+ NK cells in immunoprotection against experimental primary and secondary filarial infection which can proceed in the absence of adaptive immune regulation. [ABSTRACT FROM AUTHOR]

Lymphatic filariasis and onchocerciasis are major neglected tropical diseases affecting over 90 million people worldwide with painful and profoundly disfiguring pathologies (such as lymphoedema or blindness). Type 2 inflammation is a hallmark of filarial nematode tissue infection and is implicated both in eosinophil dependent immunity and lymphatic or ocular immunopathologies. Type-2 innate lymphoid cells (ILC2) are known to play an important role in the initiation of type 2 inflammation in helminth infection. We therefore tracked comparative IL-12Rβ2+ ILC1, ST2+ ILC2 and NKp46+ natural killer (NK) innate lymphoid cell population expansions during Brugia malayi experimental peritoneal filarial infections using either immunocompetent or immunodeficient mice. In immunocompetent BALB/c animals, NKp46+ NK cells rapidly expanded representing over 90% of the ILC population in the first week of infection, whereas, surprisingly, ST2+ ILC2 failed to expand. NKp46+ NK cell expansions were confirmed in RAG2 deficient mice lacking adaptive immunity. Ablation of the NKp46+ NK cell compartment in RAG2 common gamma chain (gc) mice led to increased susceptibility to chronic adult B. malayi infection. This data was recapitulated using an Onchocerca ochengi male worm peritoneal implant model. When NKp46+ NK cells were depleted in RAG2 deficient mice using anti-NKp46 or asialo GM1 antibody injections over the first five weeks of B. malayi infection, susceptibility to adult B. malayi infection was significantly increased by 2-3 fold with concomitant impairment in eosinophil or neutrophil recruitments. Finally, we demonstrate that in RAG2 deficient mice, drug clearance of a primary adult B. malayi infection followed by challenge infection leads to resistance against early larval B. malayi establishment. This innate resistance is associated with bolstered NK and eosinophils whereby NKp46+ NK cells express markers of memory-like/enhanced activation (increased expression of interferon gamma and Ly6C). Our data promotes a novel functional role for NKp46+ NK cells in immunoprotection against experimental primary and secondary filarial infection which can proceed in the absence of adaptive immune regulation.

Introduction Natural killer cells are a potent effector lymphocyte subset that can induce cytotoxicity without the need for antigen sensitization or presentation. NK cells are a tempting target –for immune therapy, monoclonal antibody, or genetic engineering-to enhance immune surveillance mechanisms against myeloma cells. Materials and methods We hypothesized an association between natural killer cell recovery after autologous stem cell transplantation (ASCT) and disease outcomes in multiple myeloma patients. We concluded a prospective study that started enrolling patients in January 2020 to identify the association between absolute NK cell count two to three after ASCT and disease outcomes after autologous stem cell transplantation in multiple myeloma using univariate and multivariate analysis. Results Natural killer cell recovery was evaluated during the third month after ASCT, day +60 to +90 post-ASCT. Our patients had a mean NK cell count of 90.53, ranging from 14 to 282 Cell/μL (Std Dev 84.64 Cell/μL). The odds of having a minimal residual disease (MRD-positivity) among patients with partial remission before transplantation is four times higher than patients with very good partial response or better (95% confidence interval 0.45–35.79). Our patients were classified into two groups based on MRD status after ASCT, an MRD-negative group of eight participants and an MRD-positive group of seven participants. The mean absolute NK cell count was significantly higher in the MRD-negative cohort, 131.38 Cell/μL, versus 43.86 Cell/μL in the MRD-positive group (p = 0.049). Conclusion We conclude that for multiple myeloma patients treated with ASCT, high absolute NK cell counts two to three months after ASCT is an independent predictor for MRD negativity. [ABSTRACT FROM AUTHOR]

Aging is the greatest risk factor for nearly all major chronic diseases, including cardiovascular diseases, cancer, Alzheimer's and other neurodegenerative diseases of aging. Age-related impairment of immune function (immunosenescence) is one important cause of age-related morbidity and mortality, which may extend beyond its role in infectious disease. One aspect of immunosenescence that has received less attention is age-related natural killer (NK) cell dysfunction, characterized by reduced cytokine secretion and decreased target cell cytotoxicity, accompanied by and despite an increase in NK cell numbers with age. Moreover, recent studies have revealed that NK cells are the central actors in the immunosurveillance of senescent cells, whose age-related accumulation is itself a probable contributor to the chronic sterile low-grade inflammation developed with aging ("inflammaging"). NK cell dysfunction is therefore implicated in the increasing burden of infection, malignancy, inflammatory disorders, and senescent cells with age. This review will focus on recent advances and open questions in understanding the interplay between systemic inflammation, senescence burden, and NK cell dysfunction in the context of aging. Understanding the factors driving and enforcing NK cell aging may potentially lead to therapies countering age-related diseases and underlying drivers of the biological aging process itself. [ABSTRACT FROM AUTHOR]

Human natural killer (NK) cells can target tumor cells in an antigen-specific manner by the recognition of cell bound antibodies. This process induces antibody-dependent cell-mediated cytotoxicity (ADCC) and is exclusively mediated by the low affinity IgG Fc receptor CD16A (FcγRIIIA). Exploiting ADCC by NK cells is a major area of emphasis for advancing cancer immunotherapies. CD64 (FcγRI) is the only high affinity IgG FcR and it binds to the same IgG isotypes as CD16A, but it is not expressed by human NK cells. We have generated engineered human NK cells expressing recombinant CD64 with the goal of increasing their ADCC potency. Preclinical testing of this approach is essential for establishing efficacy and safety of the engineered NK cells. The dog provides particular advantages as a model, which includes spontaneous development of cancer in the setting of an intact and outbred immune system. To advance this immunotherapy model, we cloned canine CD16A and CD64 and generated specific mAbs. We report here for the first time the expression patterns of these FcγRs on dog peripheral blood leukocytes. CD64 was expressed by neutrophils and monocytes, but not lymphocytes, while canine CD16A was expressed at high levels by a subset of monocytes and lymphocytes. These expression patterns are similar to that of human leukocytes. Based on phenotypic characteristics, the CD16A+ lymphocytes consisted of T cells (CD3+ CD8+ CD5dim α/β TCR+) and NK cells (CD3− CD5− CD94+), but not B cells. Interestingly, the majority of canine CD16A+ lymphocytes were from the T cell population. Like human CD16A, canine CD16A was downregulated by a disintegrin and metalloproteinase 17 (ADAM17) upon leukocyte activation, revealing a conserved means of regulation. We also directly demonstrate that both canine CD16A and CD64 can induce ADCC when expressed in the NK cell line NK-92. These findings pave the way to engineering canine NK cells or T cells with high affinity recombinant canine CD64 to maximize ADCC and to test their safety and efficacy to benefit both humans and dogs. [ABSTRACT FROM AUTHOR]

Human natural killer (NK) cells can target tumor cells in an antigen-specific manner by the recognition of cell bound antibodies. This process induces antibody-dependent cell-mediated cytotoxicity (ADCC) and is exclusively mediated by the low affinity IgG Fc receptor CD16A (FcγRIIIA). Exploiting ADCC by NK cells is a major area of emphasis for advancing cancer immunotherapies. CD64 (FcγRI) is the only high affinity IgG FcR and it binds to the same IgG isotypes as CD16A, but it is not expressed by human NK cells. We have generated engineered human NK cells expressing recombinant CD64 with the goal of increasing their ADCC potency. Preclinical testing of this approach is essential for establishing efficacy and safety of the engineered NK cells. The dog provides particular advantages as a model, which includes spontaneous development of cancer in the setting of an intact and outbred immune system. To advance this immunotherapy model, we cloned canine CD16A and CD64 and generated specific mAbs. We report here for the first time the expression patterns of these FcγRs on dog peripheral blood leukocytes. CD64 was expressed by neutrophils and monocytes, but not lymphocytes, while canine CD16A was expressed at high levels by a subset of monocytes and lymphocytes. These expression patterns are similar to that of human leukocytes. Based on phenotypic characteristics, the CD16A+ lymphocytes consisted of T cells (CD3+ CD8+ CD5dim α/β TCR+) and NK cells (CD3− CD5− CD94+), but not B cells. Interestingly, the majority of canine CD16A+ lymphocytes were from the T cell population. Like human CD16A, canine CD16A was downregulated by a disintegrin and metalloproteinase 17 (ADAM17) upon leukocyte activation, revealing a conserved means of regulation. We also directly demonstrate that both canine CD16A and CD64 can induce ADCC when expressed in the NK cell line NK-92. These findings pave the way to engineering canine NK cells or T cells with high affinity recombinant canine CD64 to maximize ADCC and to test their safety and efficacy to benefit both humans and dogs.

Allogeneic natural killer (aNK) cell adoptive therapy has the potential to dramatically impact clinical outcomes of glioblastoma multiforme (GBM). However, in order to exert therapeutic activity, NK cells require tumor expression of ligands for activating receptors, such as MHC Class I peptide A/B (MICA/B) and ULBPs. Here, we describe the use of a blood–brain barrier (BBB) permissive supramolecular cationic drug vehicle comprising an inhibitor of the chaperone heat shock protein 90 (Hsp90), which sustains a cytotoxic effect on GBM cells, boosts the expression of MICA/B and ULBPs on the residual population, and augments the activity of clinical-grade aNK cells (GTA002). First, we identify Hsp90 mRNA transcription and gain of function as significantly upregulated in GBM compared to other central nervous system tumors. Through a rational chemical design, we optimize a radicicol supramolecular prodrug containing cationic excipients, SCI-101, which displays >2-fold increase in relative BBB penetration compared to less cationic formulations in organoids, in vitro. Using 2D and 3D biological models, we confirm SCI-101 sustains GBM cytotoxicity 72 h after drug removal and induces cell surface MICA/B protein and ULBP mRNA up to 200% in residual tumor cells compared to the naked drug alone without augmenting the shedding of MICA/B, in vitro. Finally, we generate and test the sequential administration of SCI-101 with a clinical aNK cell therapy, GTA002, differentiated and expanded from healthy umbilical cord blood CD34+ hematopoietic stem cells. Using a longitudinal in vitro model, we demonstrate >350% relative cell killing is achieved in SCI-101–treated cell lines compared to vehicle controls. In summary, these data provide a first-of-its-kind BBB-penetrating, long-acting inhibitor of Hsp90 with monotherapy efficacy, which improves response to aNK cells and thus may rapidly alter the treatment paradigm for patients with GBM.

Endometriosis is a chronic inflammatory disorder, characterized by the presence of endometrial cells outside the uterine cavity. An increasing number of studies correlate the immune system with endometriosis, particularly NK receptors (NKR), which have been suggested to play an essential role in the pathogenesis of the disease. This systematic review aims to enlighten the role of NKR in endometriosis. A literature search was performed independently by two reviewers, to identify studies assessing the role of NKR in endometriosis. In total, 18 studies were included. Endometriosis pathogenesis seems to be marked by the overexpression of NK inhibitor receptors (KIRS), namely, CD158a+, KIR2DL1, CD94/NKG2A, PD-1, NKB1, and EB6, and inhibiting ligands such as PD-L1, HLA-E, HLA-G, and HLA-I. Concurrently, there is a decrease in NK-activating receptors and natural cytotoxicity receptors (NCRs), such as NKp46, NKp30, and NKG2D. The immune shift from NK surveillance to NK suppression is also apparent in the greater relative number of ITIM domains compared with ITAM domains in NKRs. In conclusion, NK receptor activity seems to dictate the immunocompetency of women to clear endometriotic cells from the peritoneal cavity. Future research could explore NKRs as therapeutic targets, such as that which is now well established in cancer therapy through immunotherapy.

Cetuximab has an established role in the treatment of patients with recurrent/metastatic colorectal cancer and head and neck squamous cell cancer (HNSCC). However, the long-term effectiveness of cetuximab has been limited by the development of acquired resistance, leading to tumor relapse. By contrast, immunotherapies can elicit long-term tumor regression, but the overall response rates are much more limited. In addition to epidermal growth factor (EGFR) inhibition, cetuximab can activate natural killer (NK) cells to induce antibody-dependent cellular cytotoxicity (ADCC). In view of the above, there is an unmet need for the majority of patients that are treated with both monotherapy cetuximab and immunotherapy. Accumulated evidence from (pre-)clinical studies suggests that targeted therapies can have synergistic antitumor effects through combination with immunotherapy. However, further optimizations, aimed towards illuminating the multifaceted interplay, are required to avoid toxicity and to achieve better therapeutic effectiveness. The current review summarizes existing (pre-)clinical evidence to provide a rationale supporting the use of combined cetuximab and immunotherapy approaches in patients with different types of cancer. [ABSTRACT FROM AUTHOR]

Cetuximab has an established role in the treatment of patients with recurrent/metastatic colorectal cancer and head and neck squamous cell cancer (HNSCC). However, the long-term effectiveness of cetuximab has been limited by the development of acquired resistance, leading to tumor relapse. By contrast, immunotherapies can elicit long-term tumor regression, but the overall response rates are much more limited. In addition to epidermal growth factor (EGFR) inhibition, cetuximab can activate natural killer (NK) cells to induce antibody-dependent cellular cytotoxicity (ADCC). In view of the above, there is an unmet need for the majority of patients that are treated with both monotherapy cetuximab and immunotherapy. Accumulated evidence from (pre-)clinical studies suggests that targeted therapies can have synergistic antitumor effects through combination with immunotherapy. However, further optimizations, aimed towards illuminating the multifaceted interplay, are required to avoid toxicity and to achieve better therapeutic effectiveness. The current review summarizes existing (pre-)clinical evidence to provide a rationale supporting the use of combined cetuximab and immunotherapy approaches in patients with different types of cancer.

Generalized vitiligo (GV) is characterized by white patches due to autoimmune loss of melanocytes. Regulatory T cells (Tregs) maintain immune homeostasis, while NK cells eliminate pathogens and tumors. Increased NK cell frequency and reduced Treg frequency and suppressive capacity are observed in vitiligo patients. However, studies assessing Treg-mediated suppression of NK cell functions in GV are lacking. Therefore, our study aimed to assess in vitro Treg-mediated suppression of NK cells function over K562 and SK-Mel-28 cells in 31 GV patients and 30 controls using the BrdU-cell proliferation assay. We found decreased Treg-mediated suppression of NK cell function in GV patients (p = 0.0289). Moreover, increased NK cell-mediated K562 and SK-Mel-28 cells' suppression was observed in GV patients (p = 0.0207,p = 0.0419). Disease activity-based analysis, suggested reduced Treg-mediated suppression of NK cell function and increased NK cell function in active vitiligo patients (p = 0.03,p = 0.0436). Interestingly, age-based analysis suggested decreased Treg-mediated suppression of NK cell function in 1–20 and 21–40 years age groups compared to 41–60 years age group of GV patients (p = 0.005,p = 0.0380). Overall, our study, for the first time, suggests that decreased Treg-mediated suppression of NK cells may lead to increased destruction of melanocytes in GV, and this knowledge may help in developing effective therapeutics based on Tregs and NK cells for GV. [ABSTRACT FROM AUTHOR]

Aging is the greatest risk factor for nearly all major chronic diseases, including cardiovascular diseases, cancer, Alzheimer’s and other neurodegenerative diseases of aging. Age-related impairment of immune function (immunosenescence) is one important cause of age-related morbidity and mortality, which may extend beyond its role in infectious disease. One aspect of immunosenescence that has received less attention is age-related natural killer (NK) cell dysfunction, characterized by reduced cytokine secretion and decreased target cell cytotoxicity, accompanied by and despite an increase in NK cell numbers with age. Moreover, recent studies have revealed that NK cells are the central actors in the immunosurveillance of senescent cells, whose age-related accumulation is itself a probable contributor to the chronic sterile low-grade inflammation developed with aging (“inflammaging”). NK cell dysfunction is therefore implicated in the increasing burden of infection, malignancy, inflammatory disorders, and senescent cells with age. This review will focus on recent advances and open questions in understanding the interplay between systemic inflammation, senescence burden, and NK cell dysfunction in the context of aging. Understanding the factors driving and enforcing NK cell aging may potentially lead to therapies countering age-related diseases and underlying drivers of the biological aging process itself.

Natural killer (NK) cells have a central role within the innate immune system, eliminating virally infected, foreign and transformed cells through their natural cytotoxic capacity. Release of their cytotoxic granules is tightly controlled through the balance of a large repertoire of inhibitory and activating receptors, and it is the unique combination of these receptors expressed by individual cells that confers immense diversity both in phenotype and functionality. The diverse, yet unique, NK cell repertoire within an individual is surprisingly stable over time considering the constant renewal of these cells at steady state. Here we give an overview of NK cell differentiation and discuss metabolic requirements, intra-lineage plasticity and transcriptional reprogramming during IL-15-driven homeostatic proliferation. New insights into the regulation of NK cell differentiation and homeostasis could pave the way for the successful implementation of NK cell-based immunotherapy against cancer.

We report a lymphoma patient with profound B-cell deficiency after chemotherapy combined with anti-CD20 antibody successfully treated with remdesivir and convalescent plasma for prolonged SARS-CoV-2 infection. Viral clearance was likely attributed to the robust expansion and activation of TCR Vβ2 CD8+ cytotoxic T cells and CD16 + CD56- NK cells. This is the first presentation of TCR-specific T cell oligoclonal response in COVID-19. Our study suggests that B-cell depleted patients may effectively respond to anti-SARS-CoV-2 treatment when NK and antigen-specific Tc cell response is induced.

Natural killer (NK) cells have a central role within the innate immune system, eliminating virally infected, foreign and transformed cells through their natural cytotoxic capacity. Release of their cytotoxic granules is tightly controlled through the balance of a large repertoire of inhibitory and activating receptors, and it is the unique combination of these receptors expressed by individual cells that confers immense diversity both in phenotype and functionality. The diverse, yet unique, NK cell repertoire within an individual is surprisingly stable over time considering the constant renewal of these cells at steady state. Here we give an overview of NK cell differentiation and discuss metabolic requirements, intra-lineage plasticity and transcriptional reprogramming during IL-15-driven homeostatic proliferation. New insights into the regulation of NK cell differentiation and homeostasis could pave the way for the successful implementation of NK cell-based immunotherapy against cancer. [ABSTRACT FROM AUTHOR]

Cell therapy is usually defined as the treatment or prevention of human disease by supplementation with cells that have been selected, manipulated, and pharmacologically treated or altered outside the body (ex vivo). Induced pluripotent stem cells (iPSCs), with their unique characteristics of indefinite expansion in cultures and genetic modifications, represent an ideal cell source for differentiation into specialized cell types. Cell therapy has recently become one of the most promising therapeutic approaches for cancers, and different immune cell types are selected as therapeutic platforms. Natural killer (NK) cells are shown to be effective tumor cell killers and do not cause graft-vs-host disease (GVHD), making them excellent candidates for, and facilitating the development of, “off-the-shelf” cell therapies. In this review, we summarize the progress in the past decade in the advent of iPSC technology and review recent developments in gene-modified iPSC-NK cells as readily available “off-the-shelf” cellular therapies.

NK cells have emerged as promising candidates for cancer immunotherapy, especially due to their ability to fight circulating tumor cells thereby preventing metastases formation. Hence several studies have been performed to generate and expand highly cytotoxic NK cells ex vivo, e.g., by using specific cytokines to upregulate both their proliferation and surface expression of distinct activating receptors. Apart from an enhanced activity, application of NK cells as immunotherapeutic agent further requires sufficient cell numbers and a high purity. All these parameters depend on a variety of different factors including the starting material, additives like cytokines as well as the culture system. Here we analyzed PBMC-derived NK cells of five anonymized healthy donors expanded under specific conditions in an innovative perfusion bioreactor system with respect to their phenotype, IFNγ production, and cytotoxicity in vitro. Important features of the meander type bioreactors used here are a directed laminar flow of medium and control of relevant process parameters. Cells are cultivated under “steady state” conditions in perfusion mode. Our data demonstrate that expansion of CD3+ T cell depleted PBMCs in our standardized system generates massive amounts of highly pure (>85%) and potent anti-cancer active NK cells. These cells express a variety of important receptors driving NK cell recruitment, adhesion as well as activation. More specifically, they express the chemokine receptors CXCR3, CXCR4, and CCR7, the adhesion molecules L-selectin, LFA-1, and VLA-4, the activating receptors NKp30, NKp44, NKp46, NKG2D, DNAM1, and CD16 as well as the death ligands TRAIL and Fas-L. Moreover, the generated NK cells show a strong IFNγ expression upon cultivation with K562 tumor cells and demonstrate a high cytotoxicity toward leukemic as well as solid tumor cell lines in vitro. Altogether, these characteristics promise a high clinical potency of thus produced NK cells awaiting further evaluation.

Myeloid-derived suppressor cells (MDSCs) contribute to the induction of an immune suppressive/anergic, tumor permissive environment. MDSCs act as immunosuppression orchestrators also by interacting with several components of both innate and adaptive immunity. Natural killer (NK) cells are innate lymphoid cells functioning as primary effector of immunity, against tumors and virus-infected cells. Apart from the previously described anergy and hypo-functionality of NK cells in different tumors, NK cells in cancer patients show pro-angiogenic phenotype and functions, similar to decidual NK cells. We termed the pro-angiogenic NK cells in the tumor microenvironment “tumor infiltrating NK” (TINKs), and peripheral blood NK cells in cancer patients “tumor associated NK” (TANKs). The contribution of MDSCs in regulating NK cell functions in tumor-bearing host, still represent a poorly explored topic, and even less is known on NK cell regulation of MDSCs. Here, we review whether the crosstalk between MDSCs and NK cells can impact on tumor onset, angiogenesis and progression, focusing on key cellular and molecular interactions. We also propose that the similarity of the properties of tumor associated/tumor infiltrating NK and MDSC with those of decidual NK and decidual MDSCs during pregnancy could hint to a possible onco-fetal origin of these pro-angiogenic leukocytes.

Herpes simplex viruses type 1 (HSV-1) and type 2 (HSV-2) have co-evolved with humans for thousands of years and are present at a high prevalence in the population worldwide. HSV infections are responsible for several illnesses including skin and mucosal lesions, blindness and even life-threatening encephalitis in both, immunocompetent and immunocompromised individuals of all ages. Therefore, diseases caused by HSVs represent significant public health burdens. Similar to other herpesviruses, HSV-1 and HSV-2 produce lifelong infections in the host by establishing latency in neurons and sporadically reactivating from these cells, eliciting recurrences that are accompanied by viral shedding in both, symptomatic and asymptomatic individuals. The ability of HSVs to persist and recur in otherwise healthy individuals is likely given by the numerous virulence factors that these viruses have evolved to evade host antiviral responses. Here, we review and discuss molecular mechanisms used by HSVs to evade early innate antiviral responses, which are the first lines of defense against these viruses. A comprehensive understanding of how HSVs evade host early antiviral responses could contribute to the development of novel therapies and vaccines to counteract these viruses.

Natural killer (NK) cells are cytotoxic innate lymphoid cells that participate in anti-tumour and anti-viral immune responses. Their ability to rapidly destroy abnormal cells and to enhance the anti-cancer function of dendritic cells, CD8+ T cells, and macrophages makes them an attractive target for immunotherapeutic strategies. The development of approaches that augment NK-cell activation against cancer is currently under intense preclinical and clinical research and strategies include chimeric antigen receptor NK cells, NK-cell engagers, cytokines, and immune checkpoint inhibitors. In this review, we highlight recent advances in NK-cell therapeutic development and discuss their potential to add to our armamentarium against cancer., Competing Interests: M.D.B and S.I.K have applied for a patent for peptide mediated NK cell activation. M.D.B has received research funding from Karyopharm Therapeutics., (© The Author(s) 2023. Published by Oxford University Press on behalf of the British Society for Immunology.)

Chimeric antigen receptor (CAR) NK cells are demonstrating promising activity in clinical trials and possess a favorable safety profile compared to CAR-T cells. The Killer cell Immunoglobulin-like Receptors (KIR) have a critical role in the control of NK cell function, and recently, this family of activating and inhibitory receptors have been targeted to improve CAR-NK function. These strategies include the utilisation of inhibitory KIR to reduce trogocytosis-associated NK cell fratricide, the downregulation of inhibitory KIR on CAR-NK cells to alleviate HLA mediated suppression, the selection of CAR-NK cell donors enriched for activating KIR, and the use of activating KIR intracellular domains within novel CAR constructs. These pre-clinical studies demonstrate the potential utility of targeting the KIR to improve CAR-NK cell efficacy and patient outcomes., Competing Interests: Conflicts of interest Blunt MD and Khakoo SI have applied for a patent for peptide-mediated NK cell activation. All other authors declared that there are no conflicts of interest.

It is desired to selectively kill tumor cells with little or no action on normal cells. Current treatment options are associated with significant side effects including therapy with immune check point inhibitors (ICI). ICI therapy induced side effects are due to excess production of pro-inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). At the same time, production of appropriate amounts of IL-6 and TNF-α are needed to eliminate tumor cells. Hence, methods are needed that can selectively eliminate tumor cells and tone down the side effects of cytokine storm. Studies showed that IL-6 and TNF-α activate phospholipases to induce the release of polyunsaturated fatty acids (PUFAs) from the cell membrane phospholipid pool. PUFAs form precursors to pro- and anti-inflammatory eicosanoids and are capable of suppressing IL-6 and TNF-α excess production. PUFAs are endowed with capacity to selectively kill tumor cells by augmenting free radical generation and accumulation of toxic lipid peroxides in tumor but not normal cells. NK cells, TILs (tumor infiltrating cells) and γδ T cells release toxic granules (also called as cytolytic granules) that contain unsaturated fatty acids localized between the granule delimiting membrane and the granule core. Thus, lipids are a universal component of cytolytic granules and play an important role in their cytotoxic actions. Based on this evidence, it is suggested that a combination of ICI/TILs and PUFAs may form a novel method of eliminating cancer with few side effects. [ABSTRACT FROM AUTHOR]

Herpes simplex viruses type 1 (HSV-1) and type 2 (HSV-2) have co-evolved with humans for thousands of years and are present at a high prevalence in the population worldwide. HSV infections are responsible for several illnesses including skin and mucosal lesions, blindness and even life-threatening encephalitis in both, immunocompetent and immunocompromised individuals of all ages. Therefore, diseases caused by HSVs represent significant public health burdens. Similar to other herpesviruses, HSV-1 and HSV-2 produce lifelong infections in the host by establishing latency in neurons and sporadically reactivating from these cells, eliciting recurrences that are accompanied by viral shedding in both, symptomatic and asymptomatic individuals. The ability of HSVs to persist and recur in otherwise healthy individuals is likely given by the numerous virulence factors that these viruses have evolved to evade host antiviral responses. Here, we review and discuss molecular mechanisms used by HSVs to evade early innate antiviral responses, which are the first lines of defense against these viruses. A comprehensive understanding of how HSVs evade host early antiviral responses could contribute to the development of novel therapies and vaccines to counteract these viruses. [ABSTRACT FROM AUTHOR]

Myeloid-derived suppressor cells (MDSCs) contribute to the induction of an immune suppressive/anergic, tumor permissive environment. MDSCs act as immunosuppression orchestrators also by interacting with several components of both innate and adaptive immunity. Natural killer (NK) cells are innate lymphoid cells functioning as primary effector of immunity, against tumors and virus-infected cells. Apart from the previously described anergy and hypo-functionality of NK cells in different tumors, NK cells in cancer patients show pro-angiogenic phenotype and functions, similar to decidual NK cells. We termed the pro-angiogenic NK cells in the tumor microenvironment "tumor infiltrating NK" (TINKs), and peripheral blood NK cells in cancer patients "tumor associated NK" (TANKs). The contribution of MDSCs in regulating NK cell functions in tumor-bearing host, still represent a poorly explored topic, and even less is known on NK cell regulation of MDSCs. Here, we review whether the crosstalk between MDSCs and NK cells can impact on tumor onset, angiogenesis and progression, focusing on key cellular and molecular interactions. We also propose that the similarity of the properties of tumor associated/tumor infiltrating NK and MDSC with those of decidual NK and decidual MDSCs during pregnancy could hint to a possible onco-fetal origin of these pro-angiogenic leukocytes. [ABSTRACT FROM AUTHOR]

Group 1 innate lymphoid cells (ILC) comprise the natural killer (NK) cells and ILC1 which reside within peripheral tissues. Several different ILC1 subsets have recently been characterised, however no unique markers to define these subsets have been identified. Whether ILC1 and NK cells are in fact distinct lineages, or alternately exhibit transitional molecular programs, that allow them to adapt to different tissue niches remains an open question. NK cells are the prototypic member of the Group 1 ILC and have been historically assigned the functions of what now appears to be a multi-subset family that are distributed throughout the body. This raises the question of whether each of these populations mediate distinct functions during infection and tumour immunosurveillance. Here, we review the diversity in the Group 1 ILC subsets with regards to their transcriptional regulation, localization, mobility and receptor expression and highlight the challenges in unraveling the individual functions of these different populations of cells.

The density of NK cells in tumors correlates positively with prognosis in many types of cancers. The average number of infiltrating NK cells is, however, quite modest (approximately 30 NK cells/sq.mm), even in tumors deemed to have a “high” density of infiltrating NK cells. It is unclear how such low numbers of tumor-infiltrating NK cells can influence outcome. Here, we used ovalbumin-expressing tumor cell lines and TCR transgenic, OVA-specific cytotoxic T lymphocytes (OT-I-CTLs) to determine whether the simultaneous attack by anti-tumor CTLs and IL-2-activated NK (A-NK) cells synergistically increases the overall tumor cell kill and whether upregulation of tumor MHC class-I by NK cell-derived interferon-gamma (IFNγ) improves tumor-recognition and kill by anti-tumor CTLs. At equal E:T ratios, A-NK cells killed OVA-expressing tumor cells better than OT-I-CTLs. The cytotoxicity against OVA-expressing tumor cells increased by combining OT-I-CTLs and A-NK cells, but the increase was additive rather than synergistic. A-NK cells adenovirally-transduced to produce IL-12 (A-NK IL-12 ) produced high amounts of IFNγ. The addition of a low number of A-NK IL-12 cells to OT-I-CTLs resulted in a synergistic, albeit modest, increase in overall cytotoxicity. Pre-treatment of tumor cells with NK cell-conditioned medium increased tumor MHC expression and sensitivity to CTL-mediated killing. Pre-treatment of CTLs with NK cell-conditioned medium had no effect on CTL cytotoxicity. In vivo, MHC class-I expression by OVA-expressing B16 melanoma lung metastases increased significantly within 24–48 h after adoptive transfer of A-NK IL-12 cells. OT-I-CTLs and A-NK IL-12 cells localized selectively and equally well into OVA-expressing B16 lung metastases and treatment of mice bearing 7-days-old OVA-B16 lung metastases with both A-NK IL-12 cells and OT-I-CTLs lead to a significant prolongation of survival. Thus, an important function of tumor-infiltrating NK cells may be to increase tumor cell expression of MHC class-I through secretion of IFNγ, to prepare them for recognition by tumor-specific CTLs. [ABSTRACT FROM AUTHOR]

Background and Objective: Hemophagocytic Lympho Histiocytisis (HLH) is a rare disorder. It can be primary or secondary, despite the existence of diagnostic guidelines it often remains unrecognized. Familail Hemophagocytic Lymphohistiocystisis occurs typically in children under 1 year of age, secondary HLH typically occurs after 6 years of age. The objective of the study was to highlight the clinical problem and increase awareness of the disease in children in order to facilitate diagnosis and treatment. Methods: This retrospective study was conducted over 17 months period from 1.1.2014 to 30.5.2015 in the hematology department of children's hospital and included all pediatric patients diagnosed with HLH fulfilling 5 out of 8 revised diagnostic criteria guideline of the HLH - 2004 protocol. None of the patients had genetic testing, sCD25 levels or NK cell activity testing. Results: The diagnosis of HLH was made by fulfilling 5 out of 8 clinical and laboratory diagnostic criteria for HLH in 12 patients. Their ages ranged from 3 months to 10 years, male:female ratio was 2:1, fever was present in 100% cases, splenomegaly in 100%, cytopenias in two out of three cell lines in 100%, hypertriglyceridemia in 50%, hypofibrinogenemia in 50%, elevated ferritin in 66.6%, hemophagocytosis in bone marrow in 83%, HLH was diagnosed in one patient with Chedik - Higashi syndrome, in one patient with malaria, in one patient with typhoid fever and in one case with systemic juvenile idiopathic arthritis (sJIA). Conclusion: HLH presents with a varied clinical manifestations, often under - recognized, thereby contributing to its high morbidity and mortality. Early diagnosis of HLH and underlying condition and appropriate therapy is crucial to start lifesaving management, this being possible only by keeping a high index of suspicion and using diagnostic guidelines. [ABSTRACT FROM AUTHOR]

Endometriosis is a chronic inflammatory disorder, characterized by the presence of endometrial cells outside the uterine cavity. An increasing number of studies correlate the immune system with endometriosis, particularly NK receptors (NKR), which have been suggested to play an essential role in the pathogenesis of the disease. This systematic review aims to enlighten the role of NKR in endometriosis. A literature search was performed independently by two reviewers, to identify studies assessing the role of NKR in endometriosis. In total, 18 studies were included. Endometriosis pathogenesis seems to be marked by the overexpression of NK inhibitor receptors (KIRS), namely, CD158a+, KIR2DL1, CD94/NKG2A, PD-1, NKB1, and EB6, and inhibiting ligands such as PD-L1, HLA-E, HLA-G, and HLA-I. Concurrently, there is a decrease in NK-activating receptors and natural cytotoxicity receptors (NCRs), such as NKp46, NKp30, and NKG2D. The immune shift from NK surveillance to NK suppression is also apparent in the greater relative number of ITIM domains compared with ITAM domains in NKRs. In conclusion, NK receptor activity seems to dictate the immunocompetency of women to clear endometriotic cells from the peritoneal cavity. Future research could explore NKRs as therapeutic targets, such as that which is now well established in cancer therapy through immunotherapy.

Human natural killer (NK) cells in lymphoid tissues can be categorized into three subsets: CD56 bright CD16 + , CD56 dim CD16 + and CD69 + CXCR6 + lymphoid tissue-resident (lt)NK cells. How the three subsets are functionally and developmentally related is currently unknown. Therefore, we performed single-cell RNA sequencing combined with oligonucleotide-conjugated antibodies against CD56, CXCR6, CD117 and CD34 on fresh bone marrow NK cells. A minor CD56 dim GzmK + subset was identified that shared features with CD56 bright and CD56 dim GzmK - NK cells based on transcriptome, phenotype (NKG2A high CD16 low KLRG1 high TIGIT high ) and functional analysis in bone marrow and blood, supportive for an intermediate subset. Pseudotime analysis positioned CD56 bright , CD56 dim GzmK + and CD56 dim GzmK - cells in one differentiation trajectory, while ltNK cells were developmentally separated. Integrative analysis with bone marrow cells from the Human Cell Atlas did not demonstrate a developmental connection between CD34 + progenitor and NK cells, suggesting absence of early NK cell stages in bone marrow. In conclusion, single-cell transcriptomics provide new insights on development and differentiation of human NK cells., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Melsen, van Ostaijen-ten Dam, Schoorl, Schol, van den Homberg, Lankester, Lugthart and Schilham.)

Abstract: The research on oral cancer has focused mainly on the cancer cells, their genetic changes and consequent phenotypic modifications. However, it is increasingly clear that the tumor microenvironment (TME) has been shown to be in a dynamic state of inter-relations with the cancer cells. The TME contains a variety of components including the non-cancerous cells (i.e., immune cells, resident fibroblasts and angiogenic vascular cells) and the ECM milieu [including fibers (mainly collagen and fibronectin) and soluble factors (i.e., enzymes, growth factors, cytokines and chemokines)]. Thus, it is currently assumed that TME is considered a part of the cancerous tissue and the functionality of its key components constitutes the setting on which the hallmarks of the cancer cells can evolve. Therefore, in terms of controlling a malignancy, one should control the growth, invasion and spread of the cancer cells through modifications in the TME components. This mini review focuses on the TME as a diagnostic approach and reports the recent insights into the role of different TME key components [such as carcinoma-associated fibroblasts (CAFs) and inflammation (CAI) cells, angiogenesis, stromal matrix molecules and proteases] in the molecular biology of oral carcinoma. Furthermore, the impact of TME components on clinical outcomes and the concomitant need for development of new therapeutic approaches will be discussed. [Copyright &y& Elsevier]

Abstract: It is accepted that the immune system responds to pathogens with activation of antigen-independent innate and antigen-dependent adaptive immunity. However many immune events do not fit or are even inconsistent with this notion. We developed a new homeostatic model of the immune response. This model consists of four units: a sensor, a regulator, an effector and a rehabilitator. The sensor, macrophages or lymphocytes, recognize pathogenic cells and generate alarm signals. The regulator, antigen-presenting cells, Тregs and myeloid-derived suppressor cells, evaluate the signals and together with sensor cells program the effector. The effector, programmed macrophages and lymphocytes, eliminate the pathogenic cells. The rehabilitator, M2 macrophages, restrict inflammation, provide angiogenesis and reparation of tissue damage, and restore the homeostasis. We suggest the terms “immune matrix” for a biological template of immune responses to pathogens and “matrix reprogramming” for the interdependent reprogramming of different cells in the matrix. In an adequate immune response, the matrix forms a negative feedback mechanism to support the homeostasis. We defined the cellular and phenotypic composition of a tumor immune matrix. A tumor reprograms the homeostatic negative feedback mechanism of matrix into a pathogenic positive feedback mechanism. M2 macrophages play a key role in this transformation. Therefore, macrophages are an attractive target for biotechnology. Based on our hypotheses, we are developing a cell biotechnology method for creation of macrophages with a stable antitumor phenotype. We have shown that such macrophages almost doubled the survival time of mice with tumor. [Copyright &y& Elsevier]

Highlights: [•] IFN-γ secretion is temporally induced in fetuses infected with non-cytopathic BVDV. [•] Persistently infected (PI) fetuses secrete less IFN-γ than transiently infected (TI). [•] Fetal thymus, spleen and liver are possible sources of the secreted IFN-γ. [•] IFN-γ induces upregulation of the downstream target genes in TI and PI fetuses. [•] Secreted IFN-γ contributes to partial curtailing of BVDV viremia in PI fetuses. [ABSTRACT FROM AUTHOR]

Highlights: [•] Molecular interactions between brain injury and peripheral immunity. [•] Peripheral immunity and inflammation triggering secondary injuries in the ischemic brain. [•] Anti-inflammatory effects of specific immune components. [•] Brain tissue repair facilitated by peripheral immunity and inflammation. [ABSTRACT FROM AUTHOR]

Abstract: Apoptotic cell death is critical for maintaining integrity of the epithelia as well as for removal of the virus infected cells. We assessed the role of Fas/FasL-dependent pathway in apoptosis of genital epithelium during HSV-2 infection using a murine model of HSV-2 infection applied to C57BL6, MRL-Fas lpr /J (Fas−/−) and C3-Fasl gld /J (FasL−/−) mice and an in vitro model of HSV-2 infection in monocyte RAW 264.7 and keratinocyte 291.03C cell cultures and peritoneal macrophages. In contrast to keratinocyte in vitro cultures, HSV-2 infection of the monocytic cell cultures led to early induction of apoptosis. HSV-2 infection of peritoneal macrophages isolated from Fas- and FasL-deficient mice showed decreased activation of apoptosis, which could be further blocked by caspase-9 inhibitor. Infection of Fas and FasL-deficient mice increased the percentage of apoptotic cells and activation of caspase-9 in the vaginal tissue in comparison to C57BL6 wild type strain. Furthermore, Fas and FasL-deficient mice showed increased infiltration of neutrophiles in the vaginal mucosal epithelium at 3 and 7 day of infection in contrast to HSV-2 infected wild-type mice. Our results show that while the Fas/FasL pathway during HSV-2 infection of the vaginal epithelium plays an important role in controlling early local inflammatory response, mitochondrial apoptotic pathway also becomes activated by the inflammatory reaction. [Copyright &y& Elsevier]

Abstract: KIR and their HLA ligands are encoded by two of the most diverse gene families in the human genome. The function of KIR on the NK cell is highly dependent on the normal expression of class I HLA on the target cell. Previous population studies in southern Chinese have been focused on the KIR framework genes and genotypes but little is known about the compound profiles of KIR/HLA. The present study examined 503 unrelated individuals from southern Chinese Han population for the polymorphism of KIR and class I HLA genes. All 16 KIR genes were detected in the study population and the four framework genes KIR3DL2, 3DL3, 3DP1, and 2DL4 were present in all individuals. Thirty unique KIR gene profiles were found reflecting a rather limited number of KIR haplotypes in this population. KIRAA1 was the most common profile observed in 54.7% of the samples. Among the AA1 individuals, 15.6% were homozygous for the deleted KIR2DS4. Haplotype A (74.8%) was more common than haplotype B (25.2%). HLA-C1 was a much more common ligand for 2D KIRs than C2. Bw4-80I, Bw4-80T, and the Bw4-bearing HLA-A alleles were detected at similar frequencies. The matched KIR+HLA pairs 2DL2/3+C1 (98.1%), 3DL1+Bw4 (73.3%), 3DL2+A3/11 (60.0%) were the most common ones whereas 3DS1+Bw4-80I was the least common (9.4%). A total of 193 unique compound profiles of KIR–HLA were identified in 480 informative individuals, 130 of the profiles being detected only once. The study provided a comprehensive analysis of the KIR/HLA profiles in southern Chinese in regards of the presence/absence of KIR genes, HLA ligands, matched KIR+HLA pairs, and KIR/HLA compound profiles. The results could help to better understand the role played by KIR/HLA interaction in associated diseases and clinical transplantation in southern Chinese. [Copyright &y& Elsevier]