Innate Immune Lymphocytes Research Articles

Abundant CpG-sequences in human genomes inhibit KIR3DL2-expressing NK cells.

Killer Immunoglobulin-like Receptors (KIR) comprise a diverse, highly polymorphic family of cell-surface glycoproteins that are principally expressed by Natural Killer (NK) cells. These innate immune lymphocytes fulfill vital functions in human reproduction and immune responses to viral infection. KIR3DL2 is an inhibitory NK cell receptor that recognizes a common epitope of the HLA-A3 and HLA-A11 class I glycoproteins of the major histocompatibility complex. KIR3DL2 also binds exogenous DNA containing the CpG motif. This interaction causes internalization of the KIR-DNA. Exogenous CpG-DNA typically activates NK cells, but the specificity of KIR3DL2-DNA binding and internalization is unclear. We hypothesized that KIR3DL2 binds exogenous DNA in a sequence-specific manner that differentiates pathogen DNA from self-DNA. In testing this hypothesis, we surveyed octameric CpG-DNA sequences in the human genome, and in reference genomes of all bacteria, fungi, viruses, and parasites, with focus on medically relevant species. Among all pathogens, the nucleotides flanking CpG motifs in the genomes of parasitic worms that infect humans are most divergent from those in the human genome. We cultured KIR3DL2+NKL cells with the commonest CpG-DNA sequences in either human or pathogen genomes. DNA uptake was negatively correlated with the most common CpG-DNA sequences in the human genome. These CpG-DNA sequences induced inhibitory signaling in KIR3DL2+NKL cells. In contrast, KIR3DL2+NKL cells lysed more malignant targets and produced more IFNγ after culture with CpG-DNA sequences prevalent in parasitic worms. By applying functional immunology to evolutionary genomics, we conclude that KIR3DL2 allows NK cells to differentiate self-DNA from pathogen DNA.

Adipocytes, mast cells and angiogenesis.

Healthy adipose tissue contains a wide variety of innate and adaptive immune cells, including macrophages, dendritic cells, mast cells, eosinophils, neutrophils, and lymphocytes. Numerous signaling molecules in the adipose microenvironment can positively or negatively modulate angiogenic processes, regulate the interaction between the vascular system and adipocytes, and participate in tumor progression. Mast cells are involved in the new formation or metabolism of fat, are present in abundant quantities in fatty tissue, among fat cells, and a number of mediators released from mast cells play a role in adipogenesis. Moreover, mast cells produce several pro-angiogenic factors and are involved in tumor angiogenesis. In this context, the angiogenic effect might be amplified when the adipocytes and mast cells act in concert, and treatment of adipose tissue- and mast cell-associated cancers with anti-angiogenic drugs may represent an alternative or adjuvant strategy for the treatment of these tumors.

The human cytomegalovirus protein UL147A downregulates the most prevalent MICA allele: MICA*008, to evade NK cell-mediated killing.

Natural killer (NK) cells are innate immune lymphocytes capable of killing target cells without prior sensitization. One pivotal activating NK receptor is NKG2D, which binds a family of eight ligands, including the major histocompatibility complex (MHC) class I-related chain A (MICA). Human cytomegalovirus (HCMV) is a ubiquitous betaherpesvirus causing morbidity and mortality in immunosuppressed patients and congenitally infected infants. HCMV encodes multiple antagonists of NK cell activation, including many mechanisms targeting MICA. However, only one of these mechanisms, the HCMV protein US9, counters the most prevalent MICA allele, MICA*008. Here, we discover that a hitherto uncharacterized HCMV protein, UL147A, specifically downregulates MICA*008. UL147A primarily induces MICA*008 maturation arrest, and additionally targets it to proteasomal degradation, acting additively with US9 during HCMV infection. Thus, UL147A hinders NKG2D-mediated elimination of HCMV-infected cells by NK cells. Mechanistic analyses disclose that the non-canonical GPI anchoring pathway of immature MICA*008 constitutes the determinant of UL147A specificity for this MICA allele. These findings advance our understanding of the complex and rapidly evolving HCMV immune evasion mechanisms, which may facilitate the development of antiviral drugs and vaccines.

Enhancing a Natural Killer: Modification of NK Cells for Cancer Immunotherapy.

Natural killer (NK) cells are potent innate immune system effector lymphocytes armed with multiple mechanisms for killing cancer cells. Given the dynamic roles of NK cells in tumor surveillance, they are fast becoming a next-generation tool for adoptive immunotherapy. Many strategies are being employed to increase their number and improve their ability to overcome cancer resistance and the immunosuppressive tumor microenvironment. These include the use of cytokines and synthetic compounds to bolster propagation and killing capacity, targeting immune-function checkpoints, addition of chimeric antigen receptors (CARs) to provide cancer specificity and genetic ablation of inhibitory molecules. The next generation of NK cell products will ideally be readily available as an “off-the-shelf” product and stem cell derived to enable potentially unlimited supply. However, several considerations regarding NK cell source, genetic modification and scale up first need addressing. Understanding NK cell biology and interaction within specific tumor contexts will help identify necessary NK cell modifications and relevant choice of NK cell source. Further enhancement of manufacturing processes will allow for off-the-shelf NK cell immunotherapies to become key components of multifaceted therapeutic strategies for cancer.

Mechanisms of Action of the PGLYRP1/Tag7 Protein in Innate and Acquired Immunity.

One of the promising fields of modern molecular biology is the search for new proteins that regulate the various stages of the immune response and the investigation of the molecular mechanisms of action of these proteins. Such proteins include the multifunctional protein PGLYRP1/Tag7, belonging to the PGRP-S protein family, whose gene was discovered in mice at the Institute of Gene Biology, Russian Academy of Sciences, in 1996. PGLYRP1/Tag7 is classified as a protein of innate immunity; however, it can also participate in the regulation of acquired immunity mechanisms. In this paper, we consider the involvement of PGLYRP1/Tag7 in the triggering of antimicrobial defense mechanisms and formation of subsets of cytotoxic lymphocytes that kill tumor cells. The paper emphasizes that the multifaceted functional activity of Tag7 in the immune response has to do with its ability to interact with various proteins to form stable protein complexes. Hsp70-associated Tag7 can induce the death of tumor cells carrying the TNFR1 receptor. Tag7, associated with the Mts1 (S100A4) protein, can stimulate the migration of innate and adaptive immune cytotoxic lymphocytes to a lesion site. Involvement of Tag7 in the regulation of immunological processes suggests that it may be considered as a promising agent in cancer therapy. These properties of Tag7 were used to develop autologous vaccines that have passed the first and second phases of clinical trials in patients with end-stage melanoma and renal cancer. The C-terminal peptide of Tag7, isolated by limited proteolysis, was shown to protect the cartilage and bone tissue of the ankle joint in mice with induced autoimmune arthritis and may be a promising drug for suppressing the development of inflammatory processes.

In vivo Anti-Cancer Effects of Resveratrol Mediated by NK Cell Activation

Natural killer (NK) cells are innate immune lymphocytes that play an important role in anti-viral and anti-tumour immune responses. Several cancer immunotherapy approaches targeting NK cells are currently in clinical or preclinical development. Here, we aimed to find food nutrients that activate NK cells and determine their usefulness as candidates for anti-cancer and anti-metastatic drugs. Resveratrol appeared to activate NK cells most effectively among the substances tested and synergistically increased IFN-γ secretion and NK cell cytotoxicity with interleukin-2 (IL-2). CD107a, NKp30, and NKG2D expression levels were upregulated on the surface of NK cells upon treatment with resveratrol in combination with IL-2 compared with treatment with IL-2 alone. Moreover, NK cell activity in human and mouse whole blood was enhanced upon treatment with resveratrol. Most importantly, administration of resveratrol effectively inhibited tumour growth and metastasis in mice. In conclusion, we suggest that resveratrol may represent a candidate anti-cancer drug that acts by activating NK cells in vivo.

CELL MEDIATED IMMUNITY IN PATIENTS WITH STAGE II–IV COLORECTAL CANCER WITH OR WITHOUT CIRCULATING TUMOR CELLS

Nowadays, circulating tumor cells (CTCs) are considered to be one of the most important mechanisms of tumor dissemination. Detection of CTCs in patients` blood is estimated as a prognostic factor for various tumors including colorectal cancer (CRC). However, CTCs may also be a source of tumor antigens capable of inducing both immune response and tolerance and participating in «immmunoediting». The aim of the study was to assess the parameters of cell-mediated immunity in patients with stage IIIV CRC with respect to the presence or absence of CTCs. Materials and Methods . We studied the parameters of cell-mediated immunity in 60 patients with stage IIIV CRC with respect to the presence or absence of CTCs. Before treatment, we evaluated the CTC levels in patients’ blood using CellSearch System™ and lymphocyte subsets: Т-В-NК-cells, T-reg, CD4+ and CD8+ expressing markers of activation (CD69+, СD38+, CD25+, HLA-DR+ СD95+); naïve and memory T-lymphocytes (CD45RA-/CD45RO+); NК-cells expressing CD335, perforin and granzyme B using flow cytometry (FACSCantoII, BD). Results . A difference in the immunologic parameters between patients with CTCs and without CTCs depending on the stage of CRC was found. In СTС-positive patients with locally-advanced CRC, increase in the parameters of innate immunity (CD335+ NK-cells, neutrophils` respiratory burst) and activated Th (CD38+, CD25+, HLA-DR+) was found, while in СTС-positive patients with generalized CRC, suppression of cytotoxic lymphocytes of both innate (CD56/16+) and adaptive (CD8+CD25+) immunity was observed, which is, apparently, an unfavorable prognostic factor. Conclusion . The presence of CTC in CRC patients is accompanied by some immunologic changes rather stimulating Thlink and innate immunity factors in II-III stages and doubtlessly suppressive in patients with IV stage.

Innate Lymphoid Cells: Important Regulators of Host-Bacteria Interaction for Border Defense.

Innate lymphoid cells (ILCs) are a recently discovered type of innate immune lymphocyte. They include three different groups classified by the nature of the transcription factors required for their development and by the cytokines they produce. ILCs mainly reside in tissues close to the mucosal barrier such as the respiratory and gastrointestinal tracts. Due to their close proximity to the mucosal surface, ILCs are exposed to a variety of both commensal and pathogenic bacteria. Under non-pathological conditions, ILCs have been shown to be important regulators for the maintenance of tissue homeostasis by mutual interactions with the microbiome. Besides these important functions at homeostasis, several studies have also provided emerging evidence that ILCs contribute to defense against pathogenic bacterial infection by responding rapidly to the pathogens as well as orchestrating other immune cells. In this review, we summarize recent advances in our understanding of the interactions of ILCs and bacteria, with special focus on the function of the different ILC subsets in bacterial infections.

Temporal dynamics of innate and adaptive immune responses in broiler birds to oral delivered chitosan nanoparticle-based Salmonella subunit antigens

Salmonella enterica serovar Enteritidis (S. Enteritidis, SE) infection of poultry causes a significant risk to public health through contamination of meat and eggs. Current Salmonella vaccines have failed to provide strong mucosal immunity in the intestines to reduce Salmonella shedding and food contamination. Considering the short lifespan of broilers, an easy-to-deliver, safe and effective Salmonella vaccine is urgently needed. Our goal in this study was to demonstrate the ability of chitosan nanoparticle (CNP) vaccine delivery platform in activating immune response to Salmonella antigens in broilers inoculated orally. In an initial study, soluble whole antigen of SE entrapped in CNP was inoculated but the specific immune responses were poor. Therefore, the CNP entrapped immunogenic outer membrane proteins (OMP) and flagellin (FLA) of SE and surface conjugated with FLA [CNP-(OMP + FLA)] was developed. In broilers inoculated orally with CNP-(OMP + FLA) formulation once or twice, we monitored the temporal expression of innate immune molecules and antigen specific lymphocyte proliferation. In the cecal tonsils of CNP-(OMP + FLA) inoculated birds, we observed enhanced expression of mRNA coding Toll-like receptors (TLRs)- 1, 4, 5, and 7, especially at dpv 21. In addition, both OMP and FLA specific lymphocytes proliferation at dpv 7 and 21 by CNP-(OMP + FLA) were enhanced in the spleen. In conclusion, CNP-(OMP + FLA) formulation augmented both innate and lymphocyte responses in orally inoculated broilers. Further studies are needed to determine the candidate subunit CNP vaccine’s efficacy in a challenge trial.

The pivotal roles of neddylation pathway in immunoregulation.

IntroductionProtein neddylation, one of the most important posttranslational modifications that tagging neuronal precursor cell‐expressed developmentally downregulated protein 8 onto substrate proteins, plays fundamental roles in the process of many cellular functions. A number of studies have demonstrated the critical roles of neddylation modification in multiple pathophysiological processes, but its regulatory role in the immune system has only been finitely unveiled.MethodsIn this review, the latest advances in the field of neddylation modification in regulating the immune responses are succinctly discussed.ResultsNeddylation modification acts as a crucial modulator of innate immune cells (neutrophils, macrophages, and dendritic cells) and lymphocytes. Dysregulation of neddylation alters characteristics and functions of those cells due to abnormal degradation of key signaling molecules involved in immunoregulation. Furthermore, the ectopic immune responses caused by the abnormal neddylation play pivotal roles in a variety of immune‐related diseases, such as infection, inflammation, and cancer.ConclusionsThe pivotal roles of neddylation pathway in immunoregulation are attracted more and more attention, which may provide new insights into the pathogenesis of a variety of immune‐related diseases and help to indicate new therapeutic targets and potential treatment strategies.

Natural killer cells and immunotherapy based on monoclonal antibodies

Natural killer (NK) cells are effector lymphocytes of innate immunity needed to protect against stressed cells and to destroy tumor cells and virus-infected cells. These cells play an important role in the immune surveillance of malignant cells, preventing their uncontrolled growth. Natural killer cells recognize target cells directly through their receptors, which bind to various determinants on the surface of the target cell. The receptor-ligand (secretory or membrane-bound) interaction between the NK cells and the target cells determines NK’s cell activity. The use of monoclonal antibodies in tumor therapy has increased significantly in the recent years. These antibodies are intended to block inhibitory receptors (immune checkpoint inhibitors) expressed by immune cells or to block their ligands expressed by tumor cells. Examples of such immune checkpoint molecules are the following receptors: cytotoxic T lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1) and others. This blocking inhibits tumor growth by enabling immune system reactivation. The advances in cellular immunobiology that have provided the establishment of blocking monoclonal antibodies (ipilimumab, nivolumab, etc.) and increased NK cell proliferative activity are promising therapies for neoplasms.

Dissecting the NK Cell Population in Hematological Cancers Confirms the Presence of Tumor Cells and Their Impact on NK Population Homeostasis

The innate immune lymphocyte lineage natural killer (NK) cell protects against multiple pathogens and tumor cells and contains multiple subsets that could have specific activity against different attacks. The presence of viral-sculpted NK populations has already been described, but the presence of cancer-sculpted NK is unknown. Cancer induces a broad NK cell dysfunction, but this is not related to a specific population. Here we investigate NK cell population by Uniform Manifold Approximation and Projection (UMAP) embed maps in Hodgkin lymphoma (HL) and acute myeloid leukemia (AML) patients at diagnosis and, at least 30 days, after treatment, which correlates with tumor cell clearance. Whereas we identified that the NK lineage largely responded to tumor presence by generating antitumor NK cells and renewing NK cell population with immature subsets, we failed to identify a specific “memory-like” subset with the NK cell markers used. Moreover, in patients in relapse we found basically the same NK populations that those found at diagnostic, suggesting that NK cells equally respond to the first or second tumor rise. Finally, previous CMV infection largely affects the tumor-associated changes in NK population, but the CMV-associated CD57+NKG2C+ NK population does not look like to play any role. Funding Statement: The imaging facility MRI, member of the national infrastructure France BioImaging is supported by the French National Research Agency (ANR-10-INBS-04, «Investments for the future»). The “Region Languedoc Roussillon” supports the clinical data and samples (HEMODIAG_2020). This work was supported by the PRT-K program 2018 (MV and GC; 2018-021) and Canceropole GSO Emergence (MV; 2018/2019). This work was also supported by La Ligue Regionale contre le Cancer (GC), the “Investissements d’avenir” Grant LabEx MAbImprove: ANR-10-LABX-53 (GC/MV) and the NK 001 projet financed by the “Fonds Europeen de Developpement Regional “ (FEDER-FSE-IEJ 2014/2020) and by “Region Occitanie Pyrenees Mediterranee”. Declaration of Interests: The authors declare no competing interests. Ethics Approval Statement: The use of human specimens for scientific purposes was approved by the French National Ethics Committee. All methods were carried out in accordance with the approved guidelines and regulations of this committee. Written informed consent was obtained from each patient or donor prior to surgery.

Regulatory Innate Lymphoid Cells: A new subset of innate immune lymphocytes with more potential functions to be discovered in immune regulation

Regulatory innate lymphoid cells (ILCregs) are a newly identified subset of innate immune lymphocytes. The discovery of this subset cell has revealed several inhibitory and stimulatory pathways that affect the regulatory functions of ILCregs, in addition to miRNA and other genetic molecular regulations. These pathways may play important roles in the pathogenesis and potential immunotherapy in patients with different kind of diseases, such as inflammation and ischemia / reperfusion injury of the kidney, acute myeloid leukemia, through immunomodulatory and anti-inflammatory pathway, as well as miRNA regulations. Further studies on ILCregs may be a potentially high interest in the near future.

Natural Killer Cells in Systemic Autoinflammatory Diseases: A Focus on Systemic Juvenile Idiopathic Arthritis and Macrophage Activation Syndrome

Natural killer (NK) cells are innate immune lymphocytes with potent cytolytic and immune-regulatory activities. NK cells are well-known for their ability to kill infected and malignant cells in a fast and non-specific way without prior sensitization. For this purpose, NK cells are equipped with a set of cytotoxic molecules such as perforin and apoptosis-inducing proteins. NK cells also have the capacity to produce large amounts of cytokines and chemokines that synergize with their cytotoxic function and that ensure interaction with other immune cells. A less known feature of NK cells is their capacity to kill non-infected autologous cells, such as immature dendritic cells and activated T cells and monocytes. Via the release of large amounts of TNF-α and IFN-γ, NK cells may contribute to disease pathology. Conversely they may exert a regulatory role through secretion of immuno-regulatory cytokines such as GM-CSF, IL-13, and IL-10. Thus, NK cells may be important target and effector cells in the pathogenesis of autoinflammatory diseases, in particular in those disorders associated with a cytokine storm or in conditions where immune cells are highly activated. Key examples of such diseases are systemic juvenile idiopathic arthritis (sJIA) and its well-associated complication, macrophage activation syndrome (MAS). sJIA is a chronic childhood immune disorder of unknown etiology, characterized by arthritis and systemic inflammation, including a daily spiking fever and evanescent rash. MAS is a potentially fatal complication of autoimmune and autoinflammatory diseases, and most prevalently associated with sJIA. MAS is considered as a subtype of hemophagocytic lymphohistiocytosis (HLH), a systemic hyperinflammatory disorder characterized by defective cytotoxic pathways of cytotoxic T and NK cells. In this review, we describe the established features of NK cells and provide the results of a literature survey on the reported NK cell abnormalities in monogenic and multifactorial autoinflammatory disorders. Finally, we discuss the role of NK cells in the pathogenesis of sJIA and MAS.

Immune Monitoring of CD34+ Placental Cell Derived Natural Killer Cell Therapy (PNK-007) in Phase I Study of Multiple Myeloma

Background: Natural Killer (NK) cells are innate immune lymphocytes with cytotoxic function and are critical for immune surveillance. Unlike T cells which rely on antigen-specific responses, NK cells recognize transformed cells through a variety of NK cell-specific receptor-ligand interactions. Clinical studies have highlighted the therapeutic potential of NK cell-based therapies and Celularity has developed a GMP procedure for generating PNK-007: an off-the-shelf and allogeneic NK cell product culture-expanded and differentiated from human placental CD34+ stem cells. PNK-007 was evaluated as a single-dose allogeneic cell therapy in a phase I dose-escalation study for multiple myeloma (MM) patients receiving autologous stem cell transplant (ASCT) (NCT02955550). 12 of 15 patients received subcutaneous IL-2 every 48 hours for 10 days following PNK-007 cell infusion while 3 patients in a separate cohort did not receive IL-2. Here, we report translational studies evaluating post-treatment immune reconstitution, minimal residual disease (MRD) detection at 10-5 threshold, and serum profiling of cytokines and chemokines. Methods: Patient bone marrow aspirate was collected for EuroFlow MRD assessment and immune phenotyping by flow cytometry at baseline, 90-100 days, 6 months and 1 year post-ASCT. Peripheral blood was collected at baseline, then weekly for six weeks following PNK-007 infusion, at 6 months and at 1 year post-ASCT. PNK-007 persistence, leukocyte populations, and HLA antibody panels were determined by flow cytometry. Serum was analyzed by Luminex for panel cytokines, chemokines and soluble cytokine receptors. All patients and PNK-007 drug product were typed for HLA and killer-cell immunoglobulin-like (KIR) genotype. Results: PNK-007 infusion did not interfere with immune reconstitution kinetics post-ASCT. Cohorts receiving PNK infusion 14 days post-ASCT had already recovered white blood cell counts to normal levels. One cohort receiving 3x107 PNK cells/kg 7 days post-ASCT showed an immune deficient environment (0.05x103 ± 0.004x103 leukocytes/ml, n=3), but recovered their white blood cell counts by day 21 (6.8x103 ± 1.8x103 leukocytes/ml, n=3). Using a validated Euro-flow MRD assay, 4/15 patients were MRD(-) at pre-ASCT baseline, and by day 90, 10/15 pts were MRD(-). PNK-007 persistence was not detected in patients by flow cytometry with the earliest timepoint tested being 7 days post-infusion. Panel HLA serum antibodies were not detected at any timepoint indicating the absence of alloantibodies. Withholding IL-2 administration in one cohort allowed us to evaluate its potential effects on NK cell recovery and immune reconstitution. We found that subcutaneous IL-2 q.o.d. for 10 days following PNK-007 infusion did not affect recovery kinetics and concentration of endogenous NK cells. However, these patients showed a 5-10 fold increase in serum soluble IL-2RA from baseline and elevated regulatory T cell (Treg) count in the blood versus baseline (167 ± 107 Treg/mL vs. 61 ± 33 Treg/mL, p=0.0075). Patients not receiving IL-2 saw no change in serum soluble IL-2RA or blood Treg level from baseline. CD4 and CD8 T cells from all patients retained their ability to become activated in response to ex vivo stimulation and favored release of IL-2 and IFNg. T cell effector function was maintained in all patients post-ASCT but was lost in a subset of patients at 1 year. Serum analysis showed low levels of free IL-15 at the time of PNK dosing despite the transient lymphodepleted state associated with ASCT. Cytokines associated with myeloid inflammation and T cell immunity in the month post dosing were within normal homeostatic level. Serum TGFβ was significantly lower at the day of PNK infusion compared to normal homeostatic levels. Conclusion: Translational data from a Phase I study of PNK-007 in post-ASCT MM established that dosing up to 3x107 cells/kg at 14 or 7 days post-transplant did not impair engraftment or immune reconstitution. EuroFlow MRD assessment of the bone marrow showed conversion of 6/11 patients from MRD(+) to MRD(-) by day 90 post transplant. The administration of IL-2 in this clinical study did not appear to benefit NK cell reconstitution but instead favored soluble IL2RA antagonism and increased systemic levels of Treg. These results demonstrate the feasibility of allogeneic NK cell therapy in the MM + ASCT setting and will help inform the design of further clinical studies. Disclosures Van Der Touw: Celularity, Inc.: Employment, Patents & Royalties. Kang:Celularity, Inc.: Employment, Patents & Royalties. Stout:Celularity, Inc.: Employment. Voskinarian-Berse:Celularity, Inc.: Employment. Rousseva:Celularity, Inc.: Employment. Hariri:Celularity Inc: Employment. Zhang:Celularity Inc: Employment.

Natural killer cells control metastasis via structural editing of primary tumors in mice.

Natural killer (NK) cells are innate immune lymphocytes which express an array of activating and inhibitory receptors. These receptors bind a large spectrum of ligands, which are expressed on stressed, malignantly transformed or virally infected cells, as well as on bacterial, fungal, and parasitic pathogens. The decision on whether or not to kill the target is based on the integration of activating and inhibitory signals sent downstream from NK cell receptors. One of the most prominent NK cell activating receptor families is the family of natural cytotoxicity receptors (NCRs) which includes NKp30, NKp44, and NKp46. NKp46 is the only NCR to have a fully functional mouse orthologue denoted Ncr1. Despite a large body of evidence highlighting its importance in the clearance of both solid and liquid tumors, the membrane-bound tumor ligand for NKp46 and its mouse orthologue Ncr1 is still unknown. Here we review the discovery of a novel role for NKp46/Ncr1, not only in tumor clearance but also in prevention of metastasis by structural editing of primary tumors.

627P - Immune status of patients with different stages of colorectal cancer with and without circulating tumour cells

BackgroundOur purpose was to study parameters of the cellular immunity in patients with different stages of colorectal cancer with and without circulating tumor cells (CTCs). MethodsThe presence of CTCs and parameters of the cellular immunity were studied in 60 colorectal cancer (CRC) patients: stage II – 20, stage III – 12, stage IV – 28 patients, adenocarcinoma in all cases. Blood levels of CTCs were determined before the treatment using the CellSearch System (Janssen Diagnostics, LLC) with iron microparticles coated with antibodies to epithelial cell adhesion markers EpCAM, CD45 and cytokeratins 8,18,19. Subpopulations of lymphocytes were studied using the FACSCantoII flow cytometer (BD): percentage of T-B-NК-cells, Tregs; activated CD4+ and CD8+ cells, naive T-lymphocytes and memory T cells; expression of CD335, perforin and granzyme B was evaluated in NК cells. ResultsThe results revealed a number of differences in immunological parameters in patients with and without CTCs. Stage II CRC with CTCs showed statistically significantly higher content of lymphocytes (19.1±2.7 vs 15.6±1.4%), CD335+ NK cells (44.9±7.6 vs 19.2±4.0%) and the respiratory burst index in granulocytes (97.5±1.6 vs 92.3±1.2%); p<0.05 in all cases. Stage III CRC with CTCs was characterized by decreased lymphocyte and monocyte levels, while granulocyte content increased. These patients demonstrated elevated levels of CD4+ cells with early and late activation markers: CD38+ and HLA-DR+ by 2 times, CD25+ by 6 times, p<0.05 in all cases. CTC-positive patients with stage IV CRC, compared to CTC-negative ones, showed lower levels of NK cells (16.6±2.0 vs 28.4±5.5%), CD4+CD69+(5.1±0.8 vs 8.2±1.0%), and CD8+CD25+(2.8±0.48 vs 5.5±1.1%; p<0.05). ConclusionsCTCs in locally advanced CRC is associated with stimulation of functional parameters of innate immunity and activated Th, while in metastatic CRC - with inhibition of cytotoxic lymphocytes of innate and adaptive immunity, which, apparently, is associated with poor prognosis. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.

The Role of Innate and Adaptive Immune Response Lymphocytes in Pathogenesis of Hemorrhagic Fever with Renal Syndrome

The Role of Innate and Adaptive Immune Response Lymphocytes in Pathogenesis of Hemorrhagic Fever with Renal Syndrome

An Historical Overview: The Discovery of How NK Cells Can Kill Enemies, Recruit Defense Troops, and More.

Natural killer (NK) cells were originally defined as effector lymphocytes of innate immunity characterized by the unique ability of killing tumor and virally infected cells without any prior priming and expansion of specific clones. The “missing-self” theory, proposed by Klas Karre, the seminal discovery of the first prototypic HLA class I-specific inhibitory receptors, and, later, of the Natural Cytotoxicity Receptors (NCRs) by Alessandro Moretta, provided the bases to understand the puzzling behavior of NK cells. Actually, those discoveries proved crucial also for many of the achievements that, along the years, have contributed to the modern view of these cells. Indeed, NK cells, besides killing susceptible targets, are now known to functionally interact with different immune cells, sense pathogens using TLR, adapt their responses to the local environment, and, even, mount a sort of immunological memory. In this review, we will specifically focus on the main activating NK receptors and on their crucial role in the ever-increasing number of functions assigned to NK cells and other innate lymphoid cells (ILCs).

Experimental autoimmune encephalomyelitis accelerates remyelination after lysophosphatidylcholine-induced demyelination in the corpus callosum

Experimental autoimmune encephalomyelitis (EAE) and lysophosphatidylcholine (LPC)-induced demyelination were combined to study remyelination in a pro-inflammatory context. Two groups of female C57BL/6 mice were subjected either to EAE (EAE mice) or injected with just complete Freund's adjuvant (CFA) and pertussis toxin (PTX) followed by bilateral LPC and phosphate buffered saline injections in the corpus callosum on day 7 (CFA controls). Relative to CFA controls, EAE accelerated remyelination and increased innate immune cell activation, lymphocyte infiltration and cytokine gene expression in the LPC lesions. However, compared to CFA mice, remyelination was reduced (day 14) suggesting this aggressive immune response also compromised myelin repair in EAE mice.