The Multifaceted Roles of NK Cells in the Context of Murine Cytomegalovirus and Lymphocytic Choriomeningitis Virus Infections.

NK cells belong to innate lymphoid cells and able to eliminate infected cells and tumor cells. NK cells play a valuable role in controlling viral infections. Also, they have the potential to shape the adaptive immunity via a unique crosstalk with the different immune cells. Murine models are important tools for delineating the immunological phenomena in viral infection. To decipher the immunological virus-host interactions, two major infection models are being investigated in mice regarding NK cell-mediated recognition: murine cytomegalovirus (MCMV) and lymphocytic choriomeningitis virus (LCMV). In this review, we recapitulate recent findings regarding the multifaceted role of NK cells in controlling LCMV and MCMV infections and outline the exquisite interplay between NK cells and other immune cells in these two settings. Considering that, infections with MCMV and LCMV recapitulates many physiopathological characteristics of human cytomegalovirus infection and chronic virus infections respectively, this study will extend our understanding of NK cells biology in interactions between the virus and its natural host.

Enhancing Therapeutic Efficacy of FLT3 Inhibitors with Combination Therapy for Treatment of Acute Myeloid Leukemia.

FMS-like tyrosine kinase 3 (FLT3) mutations are genetic changes found in approximately thirty percent of patients with acute myeloid leukemia (AML). FLT3 mutations in AML represent a challenging clinical scenario characterized by a high rate of relapse, even after allogeneic hematopoietic stem cell transplantation (allo-HSCT). The advent of FLT3 tyrosine kinase inhibitors (TKIs), such as midostaurin and gilteritinib, has shown promise in achieving complete remission. However, a substantial proportion of patients still experience relapse following TKI treatment, necessitating innovative therapeutic strategies. This review critically addresses the current landscape of TKI treatments for FLT3+ AML, with a particular focus on gilteritinib. Gilteritinib, a highly selective FLT3 inhibitor, has demonstrated efficacy in targeting the mutant FLT3 receptor, thereby inhibiting aberrant signaling pathways that drive leukemic proliferation. However, monotherapy with TKIs may not be sufficient to eradicate AML blasts. Specifically, we provide evidence for integrating gilteritinib with mammalian targets of rapamycin (mTOR) inhibitors and interleukin-15 (IL-15) complexes. The combination of gilteritinib, mTOR inhibitors, and IL-15 complexes presents a compelling strategy to enhance the eradication of AML blasts and enhance NK cell killing, offering a potential for improved patient outcomes.

[Immunological and neuroanatomic markers of the clinical dynamics of MCI and pre-MCI]. / Immunologicheskie i neiroanatomicheskie markery dinamiki dodementnykh kognitivnykh rasstroistv pri neiroreabilitatsii.

OBJECTIVE: To study the relationship of the parameters of immunity and systemic inflammation with the structural magnetic resonance imaging (MRI) parameters in patients with mild cognitive impairment (MCI) and pre-MCI undergoing neurocognitive rehabilitation to search for candidate markers of its effectiveness. MATERIAL AND METHODS: The main group included 49 patients, aged ≥60 years, with MCI and pre-MCI with memory impairment, who underwent a course of neurorehabilitation for 5 weeks. The control group included 19 volunteers of similar age with a total MoCA score of ≥25, who did not have cognitive impairment and immuno-inflammatory disorders. The parameters of cellular and humoral immunity and markers of inflammation were studied, and structural MRI was performed. RESULTS: The content of activated natural killer cells (NK-cells) was increased in MCI and pre-MCI (0.63±0.12% vs. 0.22±0.07% in the control group, p=2.2·10-7). The level of immunoglobulin G (IgG) <12.5 g/l in patients with MCI and pre-MCI with the Montreal Cognitive Assessment Scale (MoCA) score <22 was associated with a decrease in the volume of the right nucleus accumbens (376±35 mm3 in patients with IgG <12.5 g/l (p=0.0013) and 480±44 mm3 at IgG <12.5 g/l, 480±44 mm3 in the control group), as well as with a decrease of the thickness and volume of a number of other cortical zones. A logistic regression model including the level of immunoglobulin G, NK cells, CD8+ NK cells and right amygdala volume was constructed to predict the number of MoCA scores 6 months after the course of rehabilitation (R2=0.57; p<1·10-5; standard error of estimate: 2.93). CONCLUSION: As a result of this work, the perspectives of assessing the immunological parameters in combination with socio-demographic data and morphometric changes of the brain as potential prognostic markers of the dynamics of cognitive impairment in patients with MCI and pre-MCI after neurorehabilitation has been shown.

A scalable, spin-free approach to generate enhanced induced pluripotent stem cell-derived natural killer cells for cancer immunotherapy.

Natural killer (NK) cells play a vital role in innate immunity and show great promise in cancer immunotherapy. Traditional sources of NK cells, such as the peripheral blood, are limited by availability and donor variability. In addition, in vitro expansion can lead to functional exhaustion and gene editing challenges. This study aimed to harness induced pluripotent stem cell (iPSC) technology to provide a consistent and scalable source of NK cells, overcoming the limitations of traditional sources and enhancing the potential for cancer immunotherapy applications. We developed human placental-derived iPSC lines using reprogramming techniques. Subsequently, an optimized two-step differentiation protocol was introduced to generate high-purity NK cells. Initially, iPSCs were differentiated into hematopoietic-like stem cells using spin-free embryoid bodies (EBs). Subsequently, the EBs were transferred to ultra-low attachment plates to induce NK cell differentiation. iPSC-derived NK (iNK) cells expressed common NK cell markers (NKp46, NKp30, NKp44, CD16 and eomesodermin) at both RNA and protein levels. iNK cells demonstrated significant resilience to cryopreservation and exhibited enhanced cytotoxicity. The incorporation of a chimeric antigen receptor (CAR) construct further augmented their cytotoxic potential. This study exemplifies the feasibility of generating iNK cells with high purity and enhanced functional capabilities, their improved resilience to cryopreservation and the potential to have augmented cytotoxicity through CAR expression. Our findings offer a promising pathway for the development of potential cellular immunotherapies, highlighting the critical role of iPSC technology in overcoming challenges associated with traditional NK cell sources.

CD19-chimeric antigen receptor-invariant natural killer T cells transactivate NK cells and reduce alloreactivity.

Invariant natural killer T (iNKT) cells are a small fraction of T lymphocytes with strong cytotoxic and immunoregulatory properties. We previously showed that human culture-expanded iNKT cells prevent alloreactivity and lyse primary leukemia blasts. Here, iNKT cells have several advantages over T cells based on their immunoregulatory capabilities. Since chimeric antigen receptors (CARs) increase the benefit of immune effector cells, they play a crucial role in improvement of cytotoxic abilities of novel cellular therapeutics such as iNKT cells. In the present study, we investigated transactivation of NK cells and prevention of alloreactivity through iNKT cells transduced with a CD19-directed CAR. iNKT cells were isolated by magnetic cell separation from peripheral blood mononuclear cells and transduced with a CD19-CAR retrovirus. Transduction efficiency, purity and cell subsets were measured by flow cytometry. Transactivation and cytotoxicity assays have been established to investigate the ability of CD19-CAR-iNKT cells to transactivate primary NK cells. A mixed lymphocyte reaction (MLR) was performed to explore the inhibition of alloreactive CD3+ T cells by CD19-CAR-iNKT cells. CD19-CAR-iNKT cells are able to transactivate NK cells independent of cell contact: The expression of activation marker CD69 was significantly increased and also production of the proinflammatory cytokine interferon-gamma was higher in NK cells pretreated with CD19-CAR-iNKT cells. Consequently, the cytotoxic activity of such NK cells was significantly increased being able to lyse leukemia cells more effectively than without prior transactivation. Adding CD19-CAR-iNKT cells to an MLR resulted in a decreased expression of the T cell activation marker CD25 on alloreactive CD3+ T lymphocytes stimulated with HLA mismatched dendritic cells. Also, the proliferation of alloreactive CD3+ T lymphocytes was significantly reduced in this setting. We demonstrate that CD19-CAR-iNKT cells keep their immunoregulatory properties despite transduction with a CAR making them an attractive effector cell population for application after allogeneic hematopoietic cell transplantation. By transactivating NK cells, increasing their cytotoxic activity and suppressing alloreactive T cells, they might further improve outcomes through prevention of both relapse and graft-versus-host disease.

The basic biology of NK cells and its application in tumor immunotherapy.

Natural Killer (NK) cells play a crucial role as effector cells within the tumor immune microenvironment, capable of identifying and eliminating tumor cells through the expression of diverse activating and inhibitory receptors that recognize tumor-related ligands. Therefore, harnessing NK cells for therapeutic purposes represents a significant adjunct to T cell-based tumor immunotherapy strategies. Presently, NK cell-based tumor immunotherapy strategies encompass various approaches, including adoptive NK cell therapy, cytokine therapy, antibody-based NK cell therapy (enhancing ADCC mediated by NK cells, NK cell engagers, immune checkpoint blockade therapy) and the utilization of nanoparticles and small molecules to modulate NK cell anti-tumor functionality. This article presents a comprehensive overview of the latest advances in NK cell-based anti-tumor immunotherapy, with the aim of offering insights and methodologies for the clinical treatment of cancer patients.

Interleukin-37 exacerbates liver inflammation and promotes IFN-γ production in NK cells.

Interleukin (IL)-37, a unique member of the IL-1 family, is known for its anti-inflammatory properties. However, its effects on immune-mediated liver diseases, such as primary biliary cholangitis (PBC) and acute immune-mediated hepatitis, remain unclear. Using mouse models of autoimmune cholangitis and hepatitis induced by 2-OA-OVA and concanavalin A (Con A) respectively, we introduced the human IL-37 gene via a liver-preferred adeno-associated virus vector (AAV-IL-37) to mice, as mice lack endogenous IL-37. Our findings reveal that IL-37 did not affect autoimmune cholangitis. Surprisingly, IL-37 exacerbated inflammation in Con A-induced hepatitis rather than mitigating it. Mechanistic insights suggest that this exacerbation involves the interferon (IFN)-γ pathway, supported by elevated serum IFN-γ levels in AAV-IL-37-treated Con A mice. Specifically, IL-37 heightened the number of hepatic NK and NKT cells, increased the production of the NK cell chemoattractant CCL5, and elevated the frequency of hepatic NK and NKT cells expressing IFN-γ. Moreover, IL-37 enhanced IFN-γ secretion from NK cells when combined with other proinflammatory cytokines, highlighting its synergistic effect in promoting IFN-γ production. These unexpected outcomes underscore a novel role for IL-37 in exacerbating liver inflammation during immune-mediated liver diseases, implicating its influence on NK cells and the production of IFN-γ by these cells.

NAC1 promotes stemness and regulates myeloid-derived cell status in triple-negative breast cancer.

Triple negative breast cancer (TNBC) is a particularly lethal breast cancer (BC) subtype driven by cancer stem cells (CSCs) and an immunosuppressive microenvironment. Our study reveals that nucleus accumbens associated protein 1 (NAC1), a member of the BTB/POZ gene family, plays a crucial role in TNBC by maintaining tumor stemness and influencing myeloid-derived suppressor cells (MDSCs). High NAC1 expression correlates with worse TNBC prognosis. NAC1 knockdown reduced CSC markers and tumor cell proliferation, migration, and invasion. Additionally, NAC1 affects oncogenic pathways such as the CD44-JAK1-STAT3 axis and immunosuppressive signals (TGFß, IL-6). Intriguingly, the impact of NAC1 on tumor growth varies with the host immune status, showing diminished tumorigenicity in natural killer (NK) cell-competent mice but increased tumorigenicity in NK cell-deficient ones. This highlights the important role of the host immune system in TNBC progression. In addition, high NAC1 level in MDSCs also supports TNBC stemness. Together, this study implies NAC1 as a promising therapeutic target able to simultaneously eradicate CSCs and mitigate immune evasion.

Maintaining the Balance: Regulation of NK Cell Activity.

Natural Killer (NK) cells, integral components of the innate immune system, play a crucial role in the protection against intracellular threats. Their cytotoxic power requires that activation is tightly controlled, and in this, they take a unique position within the immune system. Rather than depending on the engagement of a single activating receptor, their activation involves a delicate balance between inhibitory and activating signals mediated through an array of surface molecules. Only when this cumulative balance surpasses a specific threshold do NK cells initiate their activity. Remarkably, the activation threshold of NK cells remains robust even when cells express vastly different repertoires of inhibitory and activating receptors. These threshold values seem to be influenced by NK cell interactions with their environment during development and after release from the bone marrow. Understanding how NK cells integrate this intricate pattern of stimuli is an ongoing area of research, particularly relevant for cellular therapies seeking to harness the anti-cancer potential of these cells by modifying surface receptor expression. In this review, we will explore some of the current dogmas regarding NK cell activation and discuss recent literature addressing advances in our understanding of this field.

VWA2 protein molecular mechanism predicts colorectal cancer: Promoting cell invasion and migration by inhibiting NK cell activation.

The onset and progression of colorectal cancer is intricately linked to a multitude of factors. Among these, immune cells present within the tumor microenvironment play a pivotal role, particularly natural killer (NK) cells, which are essential for mediating anti-tumor immunity. This study aims to elucidate the mechanism by which the VWA2 protein facilitates the invasion and migration of colorectal cancer cells through the inhibition of NK cell activation. Understanding this molecular mechanism is crucial for deciphering the underlying processes involved in colorectal cancer. To achieve the study's objectives, various methodologies were employed, including cell culture techniques, transgenic technology, and assessments of NK cell functionality. The "limma" bioinformatics tool was utilised to identify differentially expressed genes (DEGs) between samples of colon cancer or polyps and normal tissue through transcriptome sequencing. Subsequent Wien analysis was conducted to pinpoint overlapping genes of interest. The impact of VWA2 on both the invasion and migration of colorectal cancer cell lines was assessed through experiments designed for the overexpression and knockout of VWA2.In addition, flow cytometry was employed to evaluate the activation status of NK cells, enabling an analysis of how VWA2 modulates relevant signaling pathways. The findings revealed that overexpression of VWA2 led to a marked inhibition of NK cell activation, which corresponded with reduced cytotoxic activity against tumor cells. Further examination indicated that VWA2 significantly amplified the migration and invasion capabilities of colorectal cancer cells by upregulating immunosuppressive factors while simultaneously downregulating pro-inflammatory factors. Conversely, the reduction of VWA2 expression was shown to markedly enhance NK cell functionality and decrease the invasive potential of colorectal cancer cells. Thus, the evidence suggests that the VWA2 protein actively promotes the migration and invasion of colorectal cancer cells primarily by suppressing NK cell activation, highlighting its potential role as a significant contributor to tumor progression in colorectal cancer.

MicroRNA-146a deficiency enhances host protection against murine cytomegalovirus.

Natural killer (NK) cells are innate lymphoid cells that protect a host from viral infections and malignancies. MicroRNA-146a (miR-146a) is an important regulator of immune function that is highly expressed in NK cells and is further upregulated during murine cytomegalovirus (MCMV) infection. Here we utilized mice with a global targeted deletion of miR-146a to understand its impact on the innate immune responses to MCMV infection. MiR-146a-/- mice were protected from lethal MCMV infection, which was intrinsic to the hematopoietic compartment based on bone marrow chimera experiments. NK cell depletion abrogated this protection, implicating NK cells as critical for the miR-146a-/- protection from MCMV. Surprisingly, NK cells from miR-146a-deficient mice were largely similar to control NK cells with respect to development, maturation, trafficking, and effector functions. However, miR-146a-/- mice had increased NK cell numbers and frequency of the most mature Stage IV (CD27-CD11b+) NK cells in the liver at baseline, enhanced STAT1 phosphorylation, and increased selective expansion of Ly49H+ NK cells and T cells during MCMV infection. This study demonstrates a critical role for miR-146a in the host response to MCMV, arising from mechanisms that include increased NK cell numbers and early T-cell expansion.

CD8+ T Cell Biology in Cytokine Storm Syndromes.

Familial forms of hemophagocytic lymphohistiocytosis (HLH) are caused by loss-of-function mutations in genes encoding perforin as well as those required for release of perforin-containing cytotoxic granule constituent. Perforin is expressed by subsets of CD8+ T cells and NK cells, representing lymphocytes that share mechanism of target cell killing yet display distinct modes of target cell recognition. Here, we highlight recent findings concerning the genetics of familial HLH that implicate CD8+ T cells in the pathogenesis of HLH and discuss mechanistic insights from animal models as well as patients that reveal how CD8+ T cells may contribute to or drive disease, at least in part through release of IFN-γ. Intriguingly, CD8+ T cells and NK cells may act differentially in severe hyperinflammatory diseases such as HLH. We also discuss how CD8+ T cells may promote or drive pathology in other cytokine release syndromes (CSS). Moreover, we review the molecular mechanisms underpinning CD8+ T cell-mediated lymphocyte cytotoxicity, key to the development of familial HLH. Together, recent insights to the pathophysiology of CSS in general and HLH in particular are providing promising new therapeutic targets.

A predictive model for progression to clinical arthritis in at-risk individuals with arthralgia based on lymphocyte subsets and ACPA.

BACKGROUND: The presence of autoantibodies against citrullinated proteins (ACPA) significantly increases the risk of developing rheumatoid arthritis (RA). Dysregulation of lymphocyte subpopulations was previously described in RA. OBJECTIVES: To propose the predictive model for progression to clinical arthritis based on peripheral lymphocyte subsets and ACPA in individuals who are at risk of RA. METHODS: Our study included 207 at-risk individuals defined by the presence of arthralgias and either additional ACPA positivity or meeting the EULAR definition for clinically suspect arthralgia. For the construction of predictive models, 153 individuals with symptom duration ≥12 months who have not yet progressed to arthritis were included. The lymphocyte subsets were evaluated using flow cytometry and anti-CCP using ELISA. RESULTS: Out of all individuals with arthralgia, 41 progressed to arthritis. A logistic regression model with baseline peripheral blood lymphocyte subpopulations and ACPA as predictors was constructed. The resulting predictive model showed that high anti-CCP IgG, higher percentage of CD4+ T cells, and lower percentage of T and NK cells increased the probability of arthritis development. Moreover, the proposed classification decision tree showed, that individuals having both high anti-CCP IgG and low NK cells have the highest risk of developing arthritis. CONCLUSIONS: We propose a predictive model based on baseline levels of lymphocyte subpopulations and ACPA to identify individuals with arthralgia with the highest risk of progression to clinical arthritis. The final model includes T cells and NK cells, which are involved in the pathogenesis of RA. This preliminary model requires further validation in larger at-risk cohorts.

The impact of CLDN18.2 expression on effector cells mediating antibody-dependent cellular cytotoxicity in gastric cancer.

Activating antibody-dependent cellular cytotoxicity (ADCC) by targeting claudin-18 isoform 2 (CLDN18.2) using zolbetuximab, a monoclonal antibody against CLDN18.2, has been considered a promising novel therapeutic strategy for gastric cancer (GC). However, the impact of CLDN18.2 expression on natural killer (NK) cells and monocytes/macrophages-crucial effector cells of ADCC-in GC has not been fully investigated. In the present study, we assessed the impact of CLDN18.2 expression on clinical outcomes, molecular features, and the frequencies of tumor-infiltrating NK cells and macrophages, as well as peripheral blood NK cells and monocytes, in GC by analyzing our own GC cohorts. The expression of CLDN18.2 did not significantly impact clinical outcomes of GC patients, while it was significantly and positively associated with Epstein-Barr virus (EBV) status and PD-L1 expression. The frequencies of tumor-infiltrating NK cells and macrophages, as well as peripheral blood NK cells and monocytes, were comparable between CLDN18.2-positive and CLDN18.2-negative GCs. Importantly, both CLDN18.2 expression and the number of tumor-infiltrating NK cells were significantly higher in EBV-associated GC compared to other molecular subtypes. Our findings support the effectiveness of zolbetuximab in CLDN18.2-positive GC, and offer a novel insight into the treatment of this cancer type, highlighting its potential effectiveness for CLDN18.2-positive/EBV-associated GC.

Light-Controlled Bioorthogonal Chemistry Altered Natural Killer Cell Activity for Boosted Adoptive Immunotherapy.

Natural killer (NK) cell-based immunotherapy has received much attention in recent years. However, the practical application is still suffering from the decreased function, inadequate infiltration, and immunosuppressive microenvironment in solid tumor. Herein, we construct the light-responsive porphyrin Fe array-armed NK cells (denoted as NK@p-Fe) for cell behavior modulation via bioorthogonal catalysis. By installing cholesterol-modified porphyrin Fe molecules on NK cell surface, it forms a catalytic array with light-harvesting capabilities. This functionality transforms NK cells into cellular factories, capable of catalyzing the production of active agents in a light-controlled manner. The NK@p-Fe can generate active antineoplastic drug doxorubicin through bioorthogonal reactions to enhance the cytotoxic function of NK cells. Beyond drug synthesis, the NK@p-Fe can also bioorthogonally catalyze to produce FDA approved immune agonist, imiquimod (IMQ). The activated immune agonist plays a dual role by inducing DC maturation for NK cells activation and reshaping tumor immunosuppressive microenvironment for NK cells infiltration. This work represents a paradigm for modulation of adoptive cell behaviors to boost cancer immunotherapy by bioorthogonal catalysis.

NKG2D-bispecific enhances NK and CD8+ T cell antitumor immunity.

BACKGROUND: Cancer immunotherapy approaches that elicit immune cell responses, including T and NK cells, have revolutionized the field of oncology. However, immunosuppressive mechanisms restrain immune cell activation within solid tumors so additional strategies to augment activity are required. METHODS: We identified the co-stimulatory receptor NKG2D as a target based on its expression on a large proportion of CD8+ tumor infiltrating lymphocytes (TILs) from breast cancer patient samples. Human and murine surrogate NKG2D co-stimulatory receptor-bispecifics (CRB) that bind NKG2D on NK and CD8+ T cells as well as HER2 on breast cancer cells (HER2-CRB) were developed as a proof of concept for targeting this signaling axis in vitro and in vivo. RESULTS: HER2-CRB enhanced NK cell activation and cytokine production when co-cultured with HER2 expressing breast cancer cell lines. HER2-CRB when combined with a T cell-dependent-bispecific (TDB) antibody that synthetically activates T cells by crosslinking CD3 to HER2 (HER2-TDB), enhanced T cell cytotoxicity, cytokine production and in vivo antitumor activity. A mouse surrogate HER2-CRB (mHER2-CRB) improved in vivo efficacy of HER2-TDB and augmented NK as well as T cell activation, cytokine production and effector CD8+ T cell differentiation. CONCLUSION: We demonstrate that targeting NKG2D with bispecific antibodies (BsAbs) is an effective approach to augment NK and CD8+ T cell antitumor immune responses. Given the large number of ongoing clinical trials leveraging NK and T cells for cancer immunotherapy, NKG2D-bispecifics have broad combinatorial potential.

Immune profiling and functional analysis of NK and T cells in ataxia telangiectasia.

Ataxia telangiectasia (AT) is a rare autosomal-recessive disorder characterized by profound neurodegeneration, combined immunodeficiency, and an increased risk for malignant diseases. Treatment options for AT are limited, and the long-term survival prognosis for patients remains grim, primarily due to the emergence of chronic respiratory pathologies, malignancies, and neurological complications. Understanding the dysregulation of the immune system in AT is fundamental for the development of novel treatment strategies. In this context, we performed a retrospective longitudinal immunemonitoring of lymphocyte subset distribution in a cohort of AT patients (n = 65). Furthermore, we performed FACS analyses of peripheral blood mononuclear cells from a subgroup of 12 AT patients to examine NK and T cells for the expression of activating and functional markers. We observed reduced levels of peripheral blood CD3+CD8+ cytotoxic T cells, CD3+CD4+ T helper cells, and CD19+ B cells, whereas the amount of CD3--CD56+ NK cells and CD3+CD56+ NKT-like cells was similar compared with age-matched controls. Notably, there was no association between the age-dependent kinetic of T-, B-, or NK-cell counts and the occurrence of malignancy in AT patients. Additionally, our results indicate an altered NK- and T-cell response to cytokine stimulation in AT with increased levels of TRAIL, FasL, and CD16 expression in NK cells, as well as an elevated activation level of T cells in AT with notably higher expression levels of IFN-γ, CD107a, TRAIL, and FasL. Together, these findings imply function alterations in AT lymphocytes, specifically in T and NK cells, shedding light on potential pathways for innovative therapies.

Isolation of anti-tumor monoclonal antibodies targeting on MICA/B α3 domain by single B cell technology for colon cancer therapy.

Colon cancer (CC) is one of the most common gastrointestinal malignancies. Effectiveness of the existing therapies is limited. Immunotherapy is a promising complementary treatment approach for CC. Major histocompatibility complex class I-related protein A and B (MICA/B) are ligands for NK cells. Shedding of MICA/B from the surface of tumor cells by cleavage of MICA/B at the membrane proxial region in MICA/B α3 structural domain is one of immune evasion strategies leading to escape of cancer cells from immunosurveillance. In this study, we generated a panel of MICA/B monoclonal antibodies (mAbs) and identified one of mAbs, mAb RDM028, that had high binding affinity to MICA/B and recognized a site on MICA/B α3 structural domain that is critically important for cleavage of MICA/B. Our study has further demonstrated that RDM028 augmented the surface expression of MICA/B on HCT-116 human CC cells by inhibiting the MICA/B shedding resulting in the enhanced cyotoxicity of NK cells against HCT-116 human CC cells and mediated anti-tumor activity in nude mouse model of colon cancer. These results indicate that mAb RDM028 could be explored for developing as an effective immuno therapy against CC by targeting the MICA/B α3 domain to promot immunosurveillance mediated by MICA/B-NKG2D interaction.

Immunological Profiling of CD8+ and CD8- NK Cell Subpopulations and Immune Checkpoint Alterations in Early-Onset Preeclampsia and Healthy Pregnancy.

Despite the numerous studies on the clinical aspects of early-onset preeclampsia, our understanding of the immunological consequences of inadequate placenta development remains incomplete. The Th1-predominance characteristic of early-onset preeclampsia significantly impacts maternal immunotolerance, and the role of immune checkpoint molecules in these mechanisms is yet to be fully elucidated. Our study aims to fill these crucial knowledge gaps. A total of 34 pregnant women diagnosed with early-onset preeclampsia and 34 healthy pregnant women were enrolled in this study. A mononuclear cell fragment from the venous blood was separated and frozen. The CD8+ and CD8- NK cell subpopulations were identified and compared to their immune checkpoint molecule expressions using multicolor flow cytometry. The serum CD226 levels were measured by ELISA. Based on our measures, the frequency of the CD8- subpopulation was significantly higher than that of the CD8+ counterpart in both the NKdim and NKbright subsets. Significantly lower CD226 surface expressions were detected in the preeclamptic group compared to healthy women in all the investigated subpopulations. However, while no difference was observed in the level of the soluble CD226 molecule between the two groups, the CD112 and CD155 surface expressions were significantly different. Our study's findings underscore the significant role of the CD8+ and CD8- NK subpopulations in the Th1-dominated immune environment. This deepens our understanding of early-onset preeclampsia and suggests that each subpopulation could contribute to the compensation mechanisms and the restoration of the immunological balance in this condition, a crucial step toward developing effective interventions.

Neutrophil-like Monocytes Increase in Patients with Colon Cancer and Induce Dysfunctional TIGIT+ NK Cells.

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous family of immune cells including granulocytic (CD14neg/CD15+/HLA-DRneg) and monocytic subtypes (CD14+/CD15neg/HLA-DRneg). In the present study, we found a population of monocytes expressing the granulocyte marker CD15 that significantly increased in both peripheral blood (PB) and tumoral tissues of patients with colorectal cancer (CRC). Further phenotypical analysis confirmed the granulocytic-like features of this monocyte subpopulation that is associated with an increase in granulocyte-monocyte precursors (GMPs) in the PB of these patients (pts). Mechanistically, this granulocyte-like monocyte population suppressed NK cell activity by inducing TIGIT and engaging NKp30. Accordingly, an increased frequency of TIGIT+ NK cells with impaired functions was found in both the PB and tumoral tissue of CRC pts. Collectively, we provided new mechanistic explanations for tumor immune escape occurring in CRC by showing the increase in this new kind of MDSC, in both PB and CRC tissue, which is able to significantly impair the effector functions of NK cells, thereby representing a potential therapeutic target for cancer immunotherapy.