Cell Receptor Activation Research Articles

Extracellular Optogenetics to Interrogate Unmodified Primary Cell Functions.

Optogenetics often requires genetic modification of the target cells to enable the expression of specific optogenetic tools, making it difficult to study primary cells in their native state. We have recently generated a fully extracellular optogenetic system for reversible light control of T cell receptor (TCR) activation on murine naïve T cells, a cell model that is very difficult to manipulate genetically. This molecular system is very versatile and can be easily modified to study different cell systems in different species. Here we describe how to produce and use this extracellular optogenetic system to manipulate primary T cell activation.

NK cells restrain cytotoxic CD8+ T cells in the submandibular gland via PD-1-PD-L1.

The increasing use of anti-programmed cell death 1 (PD-1) immune checkpoint blockade has led to the emergence of immune-related adverse events (irAEs), including dysfunction of the submandibular gland (SMG). In this study, we investigated the immunoregulatory mechanism contributing to the susceptibility of the SMG to irAEs. We found that the SMGs of PD-1-deficient mice and anti-programmed cell death ligand 1 (PD-L1)-treated mice harbor an expanded population of CD8+ T cells. We demonstrate that natural killer (NK) cells expressing PD-L1 tightly regulate CD8+ T cells in the SMG. When this immunoregulation is disrupted, CD8+ T cells clonally expand and acquire a unique transcriptional profile consistent with T cell receptor (TCR) activation. These clonally expanded cells phenotypically overlapped with cytotoxic GzmK+ CD8+ T autoimmune cells identified in patients with primary Sjögren's syndrome. Understanding how NK cells modulate CD8+ T cell activity in the SMG opens new avenues for preventing irAEs in patients undergoing checkpoint blockade therapies.

Exploring the Mechanisms Underlying Cellular Uptake and Activation of Dendritic Cells by the GK-1 Peptide.

The use of peptides for cancer immunotherapy is a promising and emerging approach that is being intensively explored worldwide. One such peptide, GK-1, has been shown to delay the growth of triple-negative breast tumors in mice, reduce their metastatic capacity, and reverse the intratumor immunosuppression that characterizes this model. Herein, it is demonstrated that GK-1 is taken up by bone marrow dendritic cells in a dose-dependent manner 15 min after exposure, more efficiently at 37 °C than at 4 °C, implying an entrance into the cells by energy-independent and -dependent processes through clathrin-mediated endocytosis. Theoretical predictions support the binding of GK-1 to the hydrophobic pocket of MD2, preventing it from bridging TLR4, thereby promoting receptor dimerization and cell activation. GK-1 can effectively activate cells via a TLR4-dependent pathway based on in vitro studies using HEK293 and HEK293-TLR4-MD2 cells and in vivo using C3H/HeJ mice (hyporesponsive to LPS). In conclusion, GK-1 enters the cells by passive diffusion and by activation of the transmembrane Toll-like receptor 4 triggering cell activation, which could be involved in the GK-1 antitumor properties.

Polybrominated diphenyl ether flame retardants inhibit growth factor-induced activation of EGFR by binding to its extracellular domain.

For many years, polybrominated diphenyl ethers (PBDEs) were used as flame retardants in a large number of consumer products. Even though international law meanwhile prohibits the production and usage of PBDEs, these persistent and bioaccumulative chemicals still leak into the environment, and are frequently detected in wildlife and humans. Population-based studies reveal positive correlations between human PBDE exposure and various adverse health effects, emphasizing that a better understanding of the mode of action of these polybrominated chemicals is urgently needed. Therefore, we investigated the effect of two widespread PBDEs, namely BDE-47 and BDE-99, on epidermal growth factor receptor (EGFR) activity in human cells. Recent studies showed that the EGFR is not only orchestrating cellular functions, but also serves as a cell-surface receptor for dioxins, phenolic benzotriazoles and related organic pollutants. Results from in silico docking analyses, AlphaLISA-based receptor binding studies and SDS-PAGE/Western blot analyses revealed that BDE-47 and BDE-99 inhibit the growth factor-triggered activation of EGFR by binding to its extracellular domain. In keratinocytes, PBDEs also inhibit amphiregulin-induced and EGFR-mediated DNA synthesis as well as the EGFR-triggered trans-repression of the aryl hydrocarbon receptor signaling pathway. Our data identify EGFR as a cell-surface receptor for PBDEs and shed light on a novel mode of action of these ubiquitous and persistent chemicals. This finding may contribute to an improved hazard assessment of PBDEs and structurally related flame retardants.

IRF5 as a potential immunological biomarker in lung adenocarcinoma.

In the clinic, the primary conventional treatments of advanced non-small cell lung cancer (NSCLC) are surgery, radiation therapy, and chemotherapy. In recent years, immune checkpoint inhibitors (ICIs) have shown promise in optimizing therapeutic benefits when combined with other immunotherapies or standard therapies. However, effective biomarkers for distant metastasis or recurrence have yet to be identified, making it difficult to determine the best therapeutic approaches. The effect of tumor immunotherapy, as well as metastasis and recurrence, are thought to be significantly affected by the tumor immunosuppressive microenvironment. Transcription factor interferon regulatory factor 5 (IRF5) is a critical regulator of the immune response. It has been found to play an important role in malignant tumor transformation, immune regulation, clinical prognosis, and the treatment response. Nevertheless, its precise role in the advancement of NSCLC, including lung adenocarcinoma (LUAD) remains poorly understood. This study sought to investigate the expression of IRF5 in LUAD and its effect on patient prognosis, and examine the biological function of IRF5. Additionally, the study aimed to examine the association between IRF5 expression and immune cell infiltration, as well as its correlation with key immune checkpoint genes relevant to NSCLC. LUAD RNA-sequencing data and clinical information were downloaded from The Cancer Genome Atlas (TCGA) and analyzed. A tissue microarray (TMA) analysis was conducted to detect IRF5 expression, and immunofluorescence staining was performed to determine immune infiltration. Bioinformatics and TMA analyses, including a differential expression analysis, prognosis prediction analysis, correlation analysis, immune infiltration analysis, and gene set enrichment analysis (GSEA), were conducted using the TCGA dataset. The results showed that the expression levels of IRF5 were lower in the LUAD tissues than the normal lung tissues. Patients with high IRF5 expression had longer survival times than those with low IRF5 expression. IRF5 was also found to be correlated with lymph node metastasis. Nine distinct types of immune cells were identified between the groups with high and low IRF5 expression levels. Eight major immune checkpoint genes were found to be upregulated in LUAD patients with high IRF5 expression levels. The enrichment analyses showed that various immune pathways were enriched in the LUAD samples with IRF5, including T cell activation, lymphocyte activation, and T cell receptor activation. IRF5 expression is closely related to tumor immunity and immunotherapy in LUAD patients. IRF5 may be indicative of prognosis in LUAD patients.

Modulation of B cell receptor activation by antibody competition.

During repeated virus exposure, pre-existing antibodies can mask viral epitopes by competing with B cell receptors for antigen. Although this phenomenon has the potential to steer B cell responses away from conserved epitopes, the factors that influence epitope masking by competing antibodies remain unclear. Using engineered, influenza-reactive B cells, we investigate how antibodies influence the accessibility of epitopes on the viral surface. We find that membrane-proximal epitopes on influenza hemagglutinin are fundamentally at a disadvantage for B cell recognition because they can be blocked by both directly and indirectly competing antibodies. While many influenza-specific antibodies can inhibit B cell activation, the potency of masking depends on proximity of the targeted epitopes as well as antibody affinity, kinetics, and valency. Although most antibodies are inhibitory, we identify one that can enhance accessibility of hidden viral epitopes. Together, these findings establish rules for epitope masking that could help advance immunogen design.

Increased Concentrations of Dopamine in the Blood and the State of the Immune System in Practically Healthy Residents of the Northern Territories

The numerous effects of dopamine are predetermined by the fact that it, being a chemical precursor of noradrenaline, is secreted in nervous tissue, in the adrenal medulla, kidneys, intestines, and APUD cells (Apudocytes). The purpose of the work is to study the effectiveness of immune reactions at elevated concentrations of dopamine in the blood of practically healthy residents of the northern territories. The results of an immunological examination of 1064 practically healthy people aged 25-55 years living in the Arkhangelsk and Murmansk regions, as well as in the Nenets Autonomous Okrug, the Komi Republic and the Svalbard archipelago (Barentsburg) were analyzed. It was found that elevated concentrations of dopamine in peripheral venous blood were more often recorded in Arctic residents; during the polar day, dopamine concentrations are higher than in winter. Increased concentrations of dopamine in the blood of Northerners are associated with a decrease in the level of activated T cells with the transferrin receptor and IL-2, T-helper cells, as well as with increased concentrations of IL-1β, TNF-α, cortisol and thyroxine. An increase in dopamine concentration may be a consequence of a cytokine reaction in the nervous tissue to inhibit excessive receptor activity of cells by increasing the concentration of IL-10. The formation of an excess of both central hormones secreted by the pituitary gland and peripheral hormones at the same time is probably due to an increase in the sensitivity threshold of the hypothalamus, which is associated with an increase in the flow of interoceptive impulses of afferent systems.

The comparison between different therapies of Systemic Lupus Erythematosus

Abstract. The immune system has three basic functions: defense, surveillance and homeostasis. It helps us monitoring and timely eliminate mutant cells and distinguishing between alien components to maintain self-stability. However, once it loses these abilities, it could cause the autoimmune disease. In this article, I mainly discuss about the Systemic Lupus Erythematosus (SLE), a type of autoimmune diseases which is mediated by type hypersensitivity. SLE patients suffer from chronic inflammatory responses, leading to tissue damage and organ dysfunction. Therefore, purpose of therapeutic schedule is to inhibit the overactive immune system and relieve the inflammatory response. Nowadays, there are three major therapies: Glucocorticoids (GC), immunosuppression agents and belimumab. Glucocorticoids suppresses inflammatory responses and generate anti-inflammatory factors. Immunosuppression agents can not only control SLE and raise the survival rate of long-term prognosis for SLE patients. Belimumab inhibits the survival of B cells by obstructing the interaction between soluble B cell activating factor (BAFF or BLys) and receptors on B cells. This action promotes the apoptosis of auto-reactive B cells, leading to a decrease in auto-antibodies present in the serum. With the development of biotechnology, more and more advanced treatments have emerged and brings new hope to SLE patients.

A tetraspecific engager armed with a non-alpha IL-2 variant harnesses natural killer cells against B cell non-Hodgkin lymphoma.

NK cells offer a promising alternative to T cell therapies in cancer. We evaluated IPH6501, a clinical-stage, tetraspecific NK cell engager (NKCE) armed with a non-alpha IL-2 variant (IL-2v), which targets CD20 and was developed for treating B cell non-Hodgkin lymphoma (B-NHL). CD20-NKCE-IL2v boosts NK cell proliferation and cytotoxicity, showing activity against a range of B-NHL cell lines, including those with low CD20 density. Whereas it presented reduced toxicities compared with those commonly associated with T cell therapies, CD20-NKCE-IL2v showed greater killing efficacy over a T cell engager targeting CD20 in in vitro preclinical models. CD20-NKCE-IL2v also increased the cell surface expression of NK cell-activating receptors, leading to activity against CD20-negative tumor cells. In vivo studies in nonhuman primates and tumor mouse models further validated its efficacy and revealed that CD20-NKCE-IL2v induces peripheral NK cell homing at the tumor site. CD20-NKCE-IL2v emerges as a potential alternative in the treatment landscape of B-NHL.

A novel immunomodulating peptide with potential to complement oligodeoxynucleotide-mediated adjuvanticity in vaccination strategies

The identification of adjuvants to improve vaccination efficacy is a major unmet need. One approach is to augment the functionality of dendritic cells (DCs) by using Toll-like receptor-9 (TLR9) agonists such as cytosine-phosphate-guanine oligodeoxynucleotides (CpG ODNs) as adjuvants. Another approach is adjuvant selection based on production of bioactive interleukin-12 (IL-12). We report a D-peptide isomer, designated D-15800, that induces monocyte differentiation to the DC phenotype in vitro and more effectively stimulates IL-12p70 production upon T cell receptor (TCR) activation than the L-isomer. In the absence of TCR activation and either IL-12p70 or interleukin-2 production, only D-15800 activates CD4+ T and natural killer cells. In the presence of CpG ODN, D-15800 synergistically enhances production of interferon-alpha (IFN-α). Taken together with its biostability in human serum and depot retention upon injection, co-delivery of D-15800 with TLR9 agonists could serve to improve vaccine efficacy.

Imaging Initial Ca2+ Microdomains in Primary T Cells.

Local, sub-second Ca2+ signals, termed Ca2+ microdomains, are highly dynamic and short-lived Ca2+ signals, which result in a global [Ca2+]i elevation and might already determine the fate of a T cell. Upon T cell receptor activation, NAADP is formed rapidly, binding to NAADP binding proteins (HN1L/JPT2, LSM12) and their respective receptors (RyR1, TPC2) sitting on intracellular Ca2+ stores, like the ER and lysosomes, and leading to subsequent release and elevation of [Ca2+]i. To capture these fast and dynamically occurring Ca2+ signals, we developed a high-resolution imaging technique using a combination of two Ca2+ indicators, Fluo-4 AM and FuraRed AM. For postprocessing, an open-source, semi-automated Ca2+ microdomain detection approach was developed based on the programming language Python. Using this workflow, we are able to reliably detect Ca2+ microdomains on a subcellular level in primary murine and human T cells in high temporal and spatial resolution fluorescence videos. This method can also be applied to other cell types, like NK cells and murine neuronal cell lines.

Herbal Amara extract induces gastric fundus relaxation via inhibition of the M2 muscarinic receptor.

Impaired gastric accommodation is one of the most frequent symptoms of functional dyspepsia. The safety and efficacy of conventional treatments remain to be proven and alternative herbal therapies have been proposed to alleviate gastrointestinal symptoms. This preclinical study examined the role of herbal Amara extract (containing Artemisia absinthium, Centaurium erythraea, Cichorium intybus, Gentiana lutea, Juniperus communis, Achillea millefolium, Peucedanum ostruthium, Salvia officinalis, and Taraxacum extracts) on gastric (fundus) accommodation and the possible implication of muscarinic receptors in its regulation. The effect of Amara extract on fundus motility was investigated in organ baths of smooth muscle strips isolated from the fundus of guinea pigs, and the role of the muscarinic receptor pathway was evaluated using functional and radioligand binding assays in cell lines expressing the M2 or M3 muscarinic receptor. Amara extract inhibited carbachol-induced contraction of guinea pig smooth muscle strips in a dose-dependent manner. This relaxant effect was not affected by the M3 antagonist J-104129. Amara extract also inhibited M2, but not M3, receptor activity in CHO-K1 cells (IC50 219 μg mL-1), and specifically bound the M2 receptor (IC50 294 μg mL-1). Of the nine herbal components of Amara extract, Juniperus communis, P. ostruthium, and Salvia officinalis inhibited M2 receptor activity (IC50 32.0, 20.8, and 20.1 μg mL-1, respectively), and P. ostruthium was sufficient to reverse carbachol-induced exvivo contraction of guinea pig fundic smooth muscles. Amara extract relaxes gastric smooth muscles by inhibiting the M2 muscarinic receptor. This study suggests the potential benefit of Amara extract for patients with impaired gastric accommodation.

IRF5 mediates adaptive immunity via altered glutamine metabolism, mTORC1 signaling and post-transcriptional regulation following T cell receptor activation.

Although dynamic alterations in transcriptional, translational, and metabolic programs have been described in T cells, the factors and pathways guiding these molecular shifts are poorly understood, with recent studies revealing a disassociation between transcriptional responses and protein expression following T cell receptor (TCR) stimulation. Previous studies identified interferon regulatory factor 5 (IRF5) in the transcriptional regulation of cytokines, chemotactic molecules and T effector transcription factors following TCR signaling. In this study, we identified T cell intrinsic IRF5 regulation of mTORC1 activity as a key modulator of CD40L protein expression. We further demonstrated a global shift in T cell metabolism, with alterations in glutamine metabolism accompanied by shifts in T cell populations at the single cell level due to loss of Irf5. T cell conditional Irf5 knockout mice in a murine model of experimental autoimmune encephalomyelitis (EAE) demonstrated protection from clinical disease with conserved defects in mTORC1 activity and glutamine regulation. Together, these findings expand our mechanistic understanding of IRF5 as an intrinsic regulator of T effector function(s) and support the therapeutic targeting of IRF5 in multiple sclerosis.

Relacorilant plus nab-paclitaxel for the treatment of metastatic pancreatic ductal adenocarcinoma: results from the open-label RELIANT study.

Modulation of glucocorticoid receptor (GR) activity in tumor cells enhances chemotherapy efficacy. We evaluated the selective GR modulator relacorilant plus nab-paclitaxel in patients with metastatic pancreatic ductal adenocarcinoma (mPDAC) who had received at least 2 prior therapy lines. In this open-label, single-arm, phase III study, patients received once-daily oral relacorilant (100 mg, titrated to 150 mg in 25 mg increments/cycle) and nab-paclitaxel (80 mg/m2) on days 1, 8, and 15 of 28-day cycles. The primary efficacy endpoint was objective response rate (ORR) by blinded independent central review. Progression-free survival (PFS), overall survival (OS), target gene modulation, and safety were also assessed. Of 43 patients enrolled, 31 were evaluable for ORR (12 did not reach first postbaseline radiographic assessment). An interim analysis to assess whether ORR was ≥10% showed no confirmed responses and the study was discontinued. Two (6.5%) patients attained unconfirmed partial responses and 15 (48.4%) had stable disease. Fourteen of 31 (45.2%) patients had reductions in target lesion size, despite prior nab-paclitaxel exposure in 12 of the 14. Median PFS and OS were 2.4 months (95% CI, 1.4-4.2) and 3.9 months (95% CI, 2.8-4.9), respectively. The most common adverse events were fatigue and nausea. RNA analysis confirmed that relacorilant plus nab-paclitaxel suppressed 8 cortisol target genes of interest. Relacorilant plus nab-paclitaxel showed modest antitumor activity in heavily pretreated patients with mPDAC, with no new safety signals. Studies of this combination in other indications with a high unmet medical need are ongoing.

Au-modified ceria nanozyme prevents and treats hypoxia-induced pulmonary hypertension with greatly improved enzymatic activity and safety

BackgroundDespite recent advances the prognosis of pulmonary hypertension remains poor and warrants novel therapeutic options. Extensive studies, including ours, have revealed that hypoxia-induced pulmonary hypertension is associated with high oxidative stress. Cerium oxide nanozyme or nanoparticles (CeNPs) have displayed catalytic activity mimicking both catalase and superoxide dismutase functions and have been widely used as an anti-oxidative stress approach. However, whether CeNPs can attenuate hypoxia-induced pulmonary vascular oxidative stress and pulmonary hypertension is unknown.ResultsIn this study, we designed a new ceria nanozyme or nanoparticle (AuCeNPs) exhibiting enhanced enzyme activity. The AuCeNPs significantly blunted the increase of reactive oxygen species and intracellular calcium concentration while limiting proliferation of pulmonary artery smooth muscle cells and pulmonary vasoconstriction in a model of hypoxia-induced pulmonary hypertension. In addition, the inhalation of nebulized AuCeNPs, but not CeNPs, not only prevented but also blunted hypoxia-induced pulmonary hypertension in rats. The benefits of AuCeNPs were associated with limited increase of intracellular calcium concentration as well as enhancement of extracellular calcium-sensing receptor (CaSR) activity and expression in rat pulmonary artery smooth muscle cells. Nebulised AuCeNPs showed a favorable safety profile, systemic arterial pressure, liver and kidney function, plasma Ca2+ level, and blood biochemical parameters were not affected.ConclusionWe conclude that AuCeNPs is an improved reactive oxygen species scavenger that effectively prevents and treats hypoxia-induced pulmonary hypertension.Graphical

Therapeutic Potential of 1-(2-Chlorophenyl)-6,7-dimethoxy-3-methyl-3,4-dihydroisoquinoline.

The synthesized compound 1-(2-chlorophenyl) 6-7-dimethoxy-3-methyl-3,4-dihydroisoquinoline (DIQ) was investigated as a biological agent. Its potential to affect muscle contractility was predicted through in silico PASS analysis. Based on the in silico analysis, its capabilities were experimentally investigated. The study aimed to investigate the effects of DIQ on the ex vivo spontaneous contractile activity (CA) of smooth muscle (SM) tissue. DIQ was observed to reduce the strength of Ca2+-dependent contractions in SM preparations (SMP), possibly by increasing cytosolic Ca2+ levels through the activation of a voltage-gated L-type Ca2+ channel. DIQ potently affected calcium currents by modulating the function of muscarinic acetylcholine receptors (mAChRs) and 5-hydroxytryptamine (5-HT) receptors at a concentration of 50 μM. Immunohistochemical tests showed a 47% reduction in 5-HT2A and 5-HT2B receptor activity in SM cells and neurons in the myenteric plexus (MP), further confirming the effects of DIQ. Furthermore, a significant inhibition of neuronal activity was observed when the compound was co-administered with 5-HT to SM tissues. The conducted experiments confirm the ability of the isoquinoline analog to act as a physiologically active molecule to control muscle contractility and related physiological processes.

Endothelial Immunosuppression in Atherosclerosis : Translational Control by Elavl1/HuR.

Atherosclerotic plaques are defined by the accumulation of lipids and immune cells beneath the endothelium of the arterial intima. CD8 T cells are among the most abundant immune cell types in plaque, and conditions linked to their activation correlate with increased levels of cardiovascular disease. As lethal effectors of the immune response, CD8 T cell activation is suppressed at multiple levels. These checkpoints are critical in dampening autoimmune responses, and limiting damage in cardiovascular disease. Endothelial cells are well known for their role in recruiting CD8 T and other hematopoietic cells to low and disturbed flow (LDF) arterial regions that develop plaque, but whether they locally influence CD8 effector functions is unclear. Here, we show that endothelial cells can actively suppress CD8 T cell responses in settings of chronic plaque inflammation, but that this behavior is governed by expression of the RNA-binding protein Embryonic Lethal, Abnormal Vision-Like 1 (Elavl1). In response to immune cell recruitment in plaque, the endothelium dynamically shifts splicing of pre-mRNA and their translation to enhance expression of immune-regulatory proteins including C1q and CD27. This program is immuno-suppressive, and limited by Elavl1. We show this by Cdh5(PAC)-CreERT2-mediated deletion of Elavl1 (ECKO), and analysis of changes in translation by Translating Ribosome Affinity Purification (TRAP). In ECKO mice, the translational shift in chronic inflammation is enhanced, leading to increased ribosomal association of C1q components and other critical regulators of immune response and resulting in a ~70% reduction in plaque CD8 T cells. CITE-seq analysis of the remaining plaque T cells shows that they exhibit lower levels of markers associated with T cell receptor (TCR) signaling, survival, and activation. To understand whether the immunosuppressive mechanism occurred through failed CD8 recruitment or local modulation of T cell responses, we used a novel in vitro co-culture system to show that ECKO endothelial cells suppress CD8 T cell expansion-even in the presence of wild-type myeloid antigen-presenting cells, antigen-specific CD8 T cells, and antigen. Despite the induction of C1q mRNA by T cell co-culture in both wild-type and ECKO endothelial cells, we find C1q protein abundantly expressed only in co-culture with ECKO cells. Together, our data define a novel immune-suppressive transition in the endothelium, reminiscent of the transition of T cells to T-regs, and demonstrate the regulation of this process by Elavl1.

A novel and potent MICA/B antibody is therapeutically effective in KRAS LKB1 mutant lung cancer models.

Concurrent KRAS LKB1 (STK11, KL) mutant Non-Small Cell Lung Cancers (NSCLC) is particularly difficult to treat and does not respond well to current immune checkpoint blockade (ICB) therapies. This is due to numerous mechanisms including low antigen presentation limiting T cell mediated killing. To activate anti-tumor immunity, we targeted tumor cell - natural killer (NK) cell interactions. We tested whether a novel antibody based therapeutic strategy that predominantly activates natural killer (NK) cells demonstrates efficacy in pre-clinical mouse models of KL NSCLC. NK cells rely on binding of ligands, such as Major Histocompatibility Complex (MHC) class I-related chain A or B (MICA/B), to the activating receptor NKG2D. Importantly MICA and MICB are widely expressed in elevated levels across NSCLC subtypes including KL lung cancers. Proteases with the tumor microenvironment (TME) can cleave these proteins rendering tumor cells less visible to NK cells. We therefore developed a MICA monoclonal antibody, AHA-1031, which utilizes two NK cell activating receptors. AHA1031 prevents ligand shedding without interfering with binding to NKG2D while targeting cancer cells to antibody mediated cell dependent cytotoxicity (ADCC). Our therapeutic novel antibody has significant monotherapy activity in KL cancer models including xenografts of human cell lines and patient derived xenografts. Activating NK cells through MICA/B stabilization and inducing ADCC offers an alternative and potent therapy option in KL tumors. MICA/B are shed across different tumors making this therapeutic strategy universally applicable.

The distribution and chemosensory responses of pharyngeal taste buds in the sea lamprey Petromyzon marinus.

Little is known about the chemosensory system of gustation in sea lampreys, basal jawless vertebrates that feed voraciously on live prey. The objective of this study was to investigate taste bud distribution and chemosensory responses along the length of the pharynx in the sea lamprey. Scanning electron microscopy and immunocytochemistry revealed taste buds and associated axons at all six lateral pharyngeal locations between the seven pairs of internal gill pores. The most rostral pharyngeal region contained more and larger taste buds than the most caudal region. Taste receptor cell responses were recorded to sweet, bitter, amino acids and the bile acid taurocholic acid, as well as to adenosine triphosphate. Similar chemosensory responses were observed at all six pharyngeal locations with taste buds. Overall, this study shows prominent taste buds and taste receptor cell activity in the seven pharyngeal regions of the sea lamprey.

The HHV-6B U20 glycoprotein binds ULBP1, masking it from recognition by NKG2D and interfering with natural killer cell activation.

Human Herpesvirus 6B (HHV-6B) impedes host immune responses by downregulating class I MHC molecules (MHC-I), hindering antigen presentation to CD8+ T cells. Downregulation of MHC-I disengages inhibitory receptors on natural killer (NK) cells, resulting in activation and killing of the target cell if NK cell activating receptors such as NKG2D have engaged stress ligands upregulated on the target cells. Previous work has shown that HHV-6B downregulates three MHC-like stress ligands MICB, ULBP1, and ULBP3, which are recognized by NKG2D. The U20 glycoprotein of the related virus HHV-6A has been implicated in the downregulation of ULBP1, but the precise mechanism remains undetermined. We set out to investigate the role of HHV-6B U20 in modulating NK cell activity. We used HHV-6B U20 expressed as a recombinant protein or transduced into target cells, as well as HHV-6B infection, to investigate binding interactions with NK cell ligands and receptors and to assess effects on NK cell activation. Small-angle X-ray scattering was used to align molecular models derived from machine-learning approaches. We demonstrate that U20 binds directly to ULBP1 with sub-micromolar affinity. Transduction of U20 decreases NKG2D binding to ULBP1 at the cell surface but does not decrease ULBP1 protein levels, either at the cell surface or in toto. HHV-6B infection and soluble U20 have the same effect. Transduction of U20 blocks NK cell activation in response to cell-surface ULBP1.Structural modeling of the U20 - ULBP1 complex indicates some similarities to the m152-RAE1γ complex.