Chemokine Receptor Research Articles

Chemokine Receptor N-Terminus Charge Dictates Reliance on Post-Translational Modifications for Effective Ligand Capture and Following Boosting by Defense Peptides.

The chemokine receptors CCR1 and CCR5 display overlapping expression patterns and ligand dependency. Here we find that ligand activation of CCR5, not CCR1, is dependent on N-terminal receptor O-glycosylation. Release from O-glycosylation dependency is obtained by increasing CCR5 N-terminus acidity to the level of CCR1. Ligand activation of CCR5, not CCR1, drastically improves in the absence of glycosaminoglycans (GAGs). Ligand activity at both CCR1 and CCR5 is boosted by positively charged/basic peptides shown to interact with acidic chemokine receptor N-termini. We propose that receptors with an inherent low N-terminus acidity rely on post-translational modifications (PTMs) to efficiently compete with acidic entities in the local environment for ligand capture. Although crucial for initial ligand binding, strong electrostatic interactions between the ligand and the receptor N-terminus may counteract following insertion of the ligand into the receptor binding pocket and activation, a process that seems to be aided in the presence of basic peptides. Basic peptides bind to the naked CCR1 N-terminus, not the CCR5 N-terminus, explaining the loss of boosting of ligand-induced signaling via CCR5 in cells incapable of glycosylation.

Structural insights into KSHV-GPCR constitutive activation and CXCL1 chemokine recognition

Kaposi's sarcoma-associated herpesvirus (KSHV) encodes a viral G protein-coupled receptor, KSHV-GPCR, that contributes to KSHV immune evasion and pathogenesis of Kaposi's sarcoma. KSHV-GPCR shares a high similarity with CXC chemokine receptors CXCR2 and can be activated by selected chemokine ligands. Like other herpesvirus-encoded GPCRs, KSHV-GPCR is characterized by its constitutive activity by coupling to various G proteins. We investigated the structural basis of ligand-dependent and constitutive activation of KSHV-GPCR, obtaining high-resolution cryo-EM structures of KSHV-GPCR-Gi complexes with and without the bound CXCL1 chemokine. Analysis of the apo-KSHV-GPCR-Gi structure (2.81 Å) unraveled the involvement of extracellular loop 2 in constitutive activation of the receptor. In comparison, the CXCL1-bound KSHV-GPCR-Gi structure (3.01 Å) showed a two-site binding mode and provided detailed information of CXCL1 binding to a chemokine receptor. The dual activation mechanism employed by KSHV-GPCR represents an evolutionary adaptation for immune evasion and contributes to the pathogenesis of Kaposi's sarcoma. Together with results from functional assays that confirmed the structural models, these findings may help to develop therapeutic strategies for KSHV infection.

ACKR3 agonism induces heterodimerization with chemokine receptor CXCR4 and attenuates platelet function.

Platelet receptors ACKR3 and CXCR4 play a crucial role in a variety of cardiovascular diseases. Like most chemokine receptors, CXCR4 is a G protein coupled receptor that induces platelet activation. In contrast, the atypical chemokine receptor 3 (ACKR3) lacks the ability to activate heterotrimeric G proteins and its activation leads to platelet inhibition and attenuates thrombus formation. In nucleated cells, heterodimerization of ACKR3 with CXCR4 regulates CXCL12-dependent signalling. The aim of our study was to investigate the formation of ACKR3/CXCR4 heterodimers in platelets and the subsequent consequences for platelet function. Using a proximity ligation assay (PLA, Duolink®) to screen for CXCR4/ACKR3 heterodimerization inducing compounds, we found that ACKR3 agonism but not conventional platelet agonists or endogen ligands lead to heterodimer formation. To further characterize the formation of ACKR3/CXCR4 heterodimers, we studied the CXCL12-dependent platelet activation via CXCR4. Both, CXCL12-dependent platelet aggregation and collagen-dependent exvivo thrombus formation were significantly downregulated by ACKR3 agonism. Moreover, platelet intracellular calcium and Akt signalling were increased by CXCL12 and again suppressed by ACKR3-specific agonists. Previously, CXCL12 was shown to decrease platelet cAMP levels via CXCR4. Treatment with a specific ACKR3 agonist counteracted this CXCL12/CXCR4-dependent cAMP decrease. Our results reveal that the formation of platelet ACKR3/CXCR4 heterodimers is dependent on ACKR3 rather than CXCR4. Furthermore, ACKR3 agonism induced heterodimerization is associated with mitigating CXCL12/CXCR4-dependent platelet activation possibly by modulating CXCR4-dependent G protein signalling. Our results indicate possible ACKR3 agonist functions and reinforce the potential therapeutic applications of ACKR3 agonists.

International Union of Basic and Clinical Pharmacology. CXVIII. Update on the Nomenclature for Atypical Chemokine Receptors including ACKR5.

Chemokines signal through classical G protein-coupled receptors (GPCRs) to induce cell migration during development, immune homeostasis and multiple diseases. Over the last decade a subfamily of atypical chemokine receptors (ACKRs) was delineated from GPCRs based on their inability to trigger conventional G protein signaling or mediate cell migration in response to chemokines. These receptors nevertheless play an important role within the chemokine system by sequestering, transporting or internalizing chemokines thereby regulating their availability and shaping their gradients. GPR182, the recently deorphanized chemokine receptor, shares about 30% of sequence similarity with its closest relative ACKR3. GPR182 is mainly expressed on endothelial cells and was proposed to act as a scavenger regulating the availability of a large set of chemokines from the CXC, CC and XC families and to act cooperatively with ACKR3 and ACKR4. Unlike other ACKRs, GPR182 was shown to have a strong constitutive interaction with β-arrestins that is required for intracellular receptor trafficking and chemokine scavenging. Chemokine ligation of GPR182 has no additional detectable impact on β-arrestin recruitment. Genetic ablation of GPR182 affects spleen size, myelopoiesis, and serum chemokine levels, indicating its role in chemokine homeostasis and immune regulation. GPR182 was also reported to regulate immune responses to bloodborne antigens and tumorigenesis. Taken together, compelling cumulative evidence indicates that GPR182 does not trigger G protein-mediated signaling but acts as a scavenger for chemokines in vitro and in vivo strongly supporting its inclusion as ACKR5 in the systematic nomenclature of chemokine receptors. Significance Statement The summarized presented findings strongly support the designation of GPR182 as ACKR5 and its formal inclusion in the family of atypical chemokine receptors.

Immunometabolic cues recompose and reprogram the microenvironment around implanted biomaterials.

Circulating monocytes infiltrate and coordinate immune responses in tissues surrounding implanted biomaterials and in other inflamed tissues. Here we show that immunometabolic cues in the biomaterial microenvironment govern the trafficking of immune cells, including neutrophils and monocytes, in a manner dependent on the chemokine receptor 2 (CCR2) and the C-X3-C motif chemokine receptor 1 (CX3CR1). This affects the composition and activation states of macrophage and dendritic cell populations, ultimately orchestrating the relative composition of pro-inflammatory, transitory and anti-inflammatory CCR2+, CX3CR1+ and CCR2+ CX3CR1+ immune cell populations. In amorphous polylactide implants, modifying immunometabolism by glycolytic inhibition drives a pro-regenerative microenvironment principally by myeloid cells. In crystalline polylactide implants, together with arginase-1-expressing myeloid cells, T helper 2 cells and γδ+ T cells producing interleukin-4 substantially contribute to shaping the metabolically reprogrammed pro-regenerative microenvironment. Our findings inform the premise that local metabolic states regulate inflammatory processes in the biomaterial microenvironment.

CXCR3-CXCL11 Signaling Restricts Angiogenesis and Promotes Pericyte Recruitment.

Endothelial cell (EC)-pericyte interactions are known to remodel in response to hemodynamic forces; yet there is a lack of mechanistic understanding of the signaling pathways that underlie these events. Here, we have identified a novel signaling network regulated by blood flow in ECs-the chemokine receptor CXCR3 (CXC motif chemokine receptor 3) and one of its ligands, CXCL11 (CXC motif chemokine ligand 11)-that delimits EC angiogenic potential and promotes pericyte recruitment to ECs during development. We investigated the role of CXCR3 on vascular development using both 2- and 3-dimensional in vitro assays, to study EC-pericyte interactions and EC behavioral responses to blood flow. Additionally, genetic mutants and pharmacological modulators were used in zebra fish in vivo to study the impacts of CXCR3 loss and gain of function on vascular development. In vitro modeling of EC-pericyte interactions demonstrates that suppression of EC-specific CXCR3 signaling leads to loss of pericyte association with EC tubes. In vivo, phenotypic defects are particularly noted in the cranial vasculature, where we see a loss of pericyte association with ECs and expansion of the vasculature in zebra fish treated with the Cxcr3 inhibitor AMG487 or in homozygous cxcr3.1/3.2/3.3 triple mutants. We also demonstrate that CXCR3-deficient ECs are more elongated, move more slowly, and have impaired EC-EC junctions compared with their control counterparts. Our results suggest that CXCR3 signaling in ECs helps promote vascular stabilization events during development by preventing EC overgrowth and promoting pericyte recruitment.

Host cell glycosylation selects for infection with CCR5- versus CXCR4-tropic HIV-1.

Human immunodeficiency virus type 1 (HIV-1) infection involves a selection bottleneck that leads to transmission of one or a few variants. C-C motif chemokine receptor 5 (CCR5) or C-X-C motif chemokine receptor 4 (CXCR4) can act as coreceptors for HIV-1 viral entry. However, initial infection mostly occurs via CCR5, despite abundant expression of CXCR4 on target cells. The host factors that influence HIV-1 susceptibility and selection during transmission are unclear. Here we conduct CRISPR-Cas9 screens and identify SLC35A2 (a transporter of UDP-galactose expressed in target cells in blood and mucosa) as a potent and specific CXCR4-tropic restriction factor in primary target CD4+ T cells. SLC35A2 inactivation, which resulted in truncated glycans, not only increased CXCR4-tropic infection levels but also decreased those of CCR5-tropic strains consistently. Single-cycle infections demonstrated that the effect is cell-intrinsic. These data support a role for a host protein that influences glycan structure in regulating HIV-1 infection. Host cell glycosylation may, therefore, affect HIV-1 selection during transmission in vivo.

Plasma Interleukin-13 Levels Correlate With the Severity of Symptoms Induced by Functional Dyspepsia.

Functional dyspepsia (FD) is a gastrointestinal functional disorder of the upper gastrointestinal tract that affects the quality of life of patients and poses a significant economic burden. It has been proposed that the local inflammatory immune response at the duodenum is associated with an increase in intestinal permeability, favoring the recruitment of Th2 cells and granulocyte degranulation. Moreover, systemic immune response could also be related to the symptoms of FD. The objective of this study was to evaluate the systemic immune response in Uruguayan patients with FD by analyzing the cytokine levels in plasma and the frequency of circulating T cells associated with duodenal recruitment. An analytic and cross-sectional study in 30 patients with FD and 15 healthy controls (HCs) was carried out. Patients were diagnosed with FD according to the Roma IV Committee definition. Cytokine levels were measured in plasma by a specific assay. Expression of α4β7 and CC chemokine receptor9 in circulating T cells was evaluated by flow cytometry. Higher levels of interleukin (IL)-5, IL-13, and IL-8 and lower levels of IL-10 and IL-12p70 were detected in patients with FD than in HC. Furthermore, a positive linear correlation between IL-13 and the severity of FD symptoms was found. CD4 + T cells from patients with FD expressed higher levels of α4β7 and CC chemokine receptor9 than those from HC. An increase of Th2-like cytokines and a positive correlation between the levels of plasma IL-13 and the severity of symptoms in patients with FD from Uruguay were detected.

Pleiotropic role of CCR9/CCL25 signaling in adriamycin-induced cardiomyopathy

IntroductionAdriamycin (ADR)-induced cardiomyopathy is a common problem in many cancer survivors. Recently, specific chemokine receptors have garnered interest as therapeutic targets in cardiovascular diseases. ObjectivesThis study aim to report the role of C–C chemokine receptor 9 (CCR9)/C–C chemokine ligand 25 (CCL25) and its therapeutic potential in ADR-induced cardiomyopathy. MethodsFunctional gene knockout and overexpression mouse models were utilized to investigate the role of CCR9 against ADR-induced cardiomyopathy. Transcriptome sequencing was also performed to identify the downstream molecular mechanisms of CCR9. ResultsThis study revealed that CCR9 and CCL25 levels were increased in mice and HL-1 cells injured by ADR, consistent with the results of patients with heart failure. Both in vivo and in vitro, CCR9 overexpression overtly aggravated cardiac dysfunction, accompanied by decreased AMPK activity and increased mitochondrial dysfunction, fibrosis, oxidative stress, and apoptosis. However, the cardiac harmful effects of ADR were reserved by CCR9 knockdown, as well as CCR9 overexpression aggravated cardiotoxicity were reserved by AMPK agonist GSK621. By constructing different domain-missing CCR9 mutants, we suspected that the △4 region of CCR9 is important for AMPK activity. Furthermore, transcriptome sequencing further illustrated the mechanism of CCR9 overexpression aggravated ADR-induced cardiotoxicity, which was associated with CYP1A1. Finally, lithospermic acid (LA) was screened and alleviated ADR-induced cardiotoxicity through regulation of CCR9/CCL25-AMPK signaling, bolstering CCR9-targeted potential clinical application. ConclusionThese findings present a promising target and drug for treating chemotherapy-induced cardiotoxicity.

The chemokine receptor type 5 inhibitor maraviroc alleviates sepsis-associated liver injury by regulating MAPK/NF-κB signaling.

Sepsis-related organ damage, as the most intractable problem in intensive care units (ICUs), receives a great deal of attention from healthcare professionals. Sepsis-associated liver injury (SALI) often leads to poor clinical outcomes due to its complex physiological mechanism. In previous studies, chemokine receptor 5 (CCR5) inhibitors were shown to exert unique anti-inflammatory effects. As the therapeutic effect of maraviroc (MVC) on SALI is still unclear, we aimed to explore whether MVC is effective in treating SALI. We established a model of SALI by cecal ligation and puncture (CLP) and intraperitoneally injected 20mg/kg MVC 2h after CLP. The results showed that MVC could significantly ameliorate liver injury after CLP. Furthermore, we demonstrated that MVC reduced inflammatory infiltration and apoptosis after SALI. In addition, we found that the function of MVC in reducing inflammation was obtained through the inhibition of the two inflammatory signaling pathways mentioned above. Finally, the JNK agonist AN was chosen for reverse research. As shown by the results, the therapeutic effects of MVC disappeared after AN treatment, indicating that MVC exerted anti-inflammatory and antiapoptotic effects through JNK. Our study revealed that MVC could reduce liver injury after SALI by inhibiting liver inflammation and hepatocyte apoptosis induced by CLP and that MVC exerted diminish inflammatory effects by inhibiting the NF-κB and MAPK signaling pathways.

Dinámica de los receptores de quimioquinas en la membrana celular

Chemokines are chemotactic cytokines that control the migratory patterns and positioning of many cells, including immune cells. Although chemokines were initially considered to be important mediators of acute inflammation, we now know that this complex system of ligands and receptors is essential for the generation of primary and secondary adaptive cellular and humoral immune responses. In addition, they also trigger other biological responses ranging from cell polarization or movement or the prevention of HIV-1 infection. Chemokine-mediated cell activation was believed to be due to the binding of a monomeric chemokine to its monomeric receptor. However, the biology of these mediators is more complex than initially anticipated, as several studies indicate that chemokines dimerize. In addition, the use of new advanced optical imaging techniques have made possible to determine that the receptors also form dimers, homo- and heterodimers, as well as higher order oligomers at the cell surface. These are very dynamic and plastic structures/conformations, influenced by the presence of ligands, the co-expression of other receptors and proteins, the lipid composition of the cell membrane or the environment where cells perform their function. Keywords: Chemokines; Chemokine receptors; Receptor conformation; Molecular dynamics; Signaling

Gram-negative microflora dysbiosis facilitates tumor progression and immune evasion by activating CCL3/CCL5-CCR1-MAPK-PD-L1 pathway in esophageal squamous cell carcinoma.

Gram-negative micro-flora dysbiosis occurs in multiple digestive tumors and is found to be the dominant micro-flora in esophageal squamous cell carcinoma (ESCC) micro-environment. The continuous stimulation of G- bacterium metabolites may cause tumorigenesis and reshape the micro-immune environment in ESCC. However, the mechanism of G- bacilli causing immune evasion in ESCC remains underexplored. We identified CC Chemokine receptor 1 (CCR1) as a tumor-indicating gene in ESCC. Interestingly, expression levels of CCR1 and PD-L1 were mutually up regulated after G- bacilli metabolites lipopolysaccharide (LPS) stimulation. Firstly, we found CCR1 high expression level to be associated with poor overall survival in ESCC. Importantly, we found that high level expression of CCR1 up-regulated PD-L1 expression by activating MAPK phosphorylation in ESCC and induced tumor malignant behavior. Finally, we found that T cells exhaustion and cytotoxicity suppression were associated with CCR1 expression in ESCC, which were decreased after CCR1 inhibiting. Our work identifies CCR1 as a potential immune check point regulator of PD-L1 and may cause T cell exhaustion and cytotoxicity suppression in ESCC micro-environment and highlights the potential value of CCR1 as therapeutic target of immunotherapy. Implications: The esophageal microbial environment and its metabolites significantly affect the outcome of immunotherapy for ESCC.

Transcriptomic analysis of immune-related genes in Pacific white snook (Centropomus viridis) gills infected with the monogenean parasite Rhabdosynochus viridisi

The parasite Rhabdosynochus viridisi (Platyhelminthes: Monogenea) infects the Pacific white snook Centropomus viridis gills and can cause adverse effects in the aquaculture industry. The immune responses of Pacific white snook to monogenean infections are poorly understood. Thus, this study aimed to identify differentially expressed genes (DEGs) in the gills of Pacific white snook juveniles experimentally infected with R. viridisi, emphasizing immune-related genes and pathways activated or suppressed during the infection. RNA sequencing was performed on the gills of uninfected (control) and infected fish. The algorithm Seq2Fun was selected without a reference transcriptome to map the reads to transcripts of fishes available from a database for gene orthologs (EcoOmics) and obtain the counting table. The ExpressAnalyst software was used for differential expression and functional analyses. A total of 20,106 transcripts were found, and 1430 (7 %) were differentially expressed genes (DEGs) between infected and control groups. We identified 860 (60 %) downregulated and 570 (40 %) upregulated genes. Thirteen canonical pathways after the Kyoto Encyclopedia of Genes and Genomes (KEGG) database were overrepresented, and most of the DEGs were downregulated, suggesting the inactivation of these pathways. The functions of most of the DEGs with higher fold change found in this study are poorly understood in fish. Even though the well-known pro-inflammatory cytokines remained unchanged in infected gills of C. viridis, and transforming growth factor β (tgfβ) was downregulated, interleukin-17 ligands il17d and il17a/f1, as well as C-X-C motif chemokine receptor 2 (cxcr2) genes were upregulated, indicating that the infection with R. viridisi promotes Th17-like immunity. Overexpression of plasma B cell activity markers such as immunoglobulin light chain-like genes and the v-set pre-B cell surrogate light chain 3 (vpreb3) was also detected in this study. The possible implications of DEGs related to calcium imbalance, hypoxia adaptation, hemostasis, and immunity are discussed. These results will support future studies to improve the prevention and treatment of monogenean infections in finfish aquaculture.

Virtual Screening of Flavonoids against Plasmodium vivax Duffy Binding Protein Utilizing Molecular Docking and Molecular Dynamic Simulation.

Plasmodium vivax (P. vivax) is one of the highly prevalent human malaria parasites. Due to the presence of extravascular reservoirs, P. vivax is extremely challenging to manage and eradicate. Traditionally, flavonoids have been widely used to combat various diseases. Recently, biflavonoids were discovered to be effective against Plasmodium falciparum. In this study, in silico approaches were utilized to inhibit Duffy binding protein (DBP), responsible for Plasmodium invasion into red blood cells (RBC). The interaction of flavonoid molecules with the Duffy antigen receptor for chemokines (DARC) binding site of DBP was investigated using a molecular docking approach. Furthermore, molecular dynamic simulation studies were carried out to study the stability of top-docked complexes. The results showed the effectiveness of flavonoids, such as daidzein, genistein, kaempferol, and quercetin, in the DBP binding site. These flavonoids were found to bind in the active region of DBP. Furthermore, the stability of these four ligands was maintained throughout the 50 ns simulation, maintaining stable hydrogen bond formation with the active site residues of DBP. The present study suggests that flavonoids might be good candidates and novel agents against DBP-mediated RBC invasion of P. vivax and can be further analyzed in in vitro studies.

An overview of the role of chemokine CX3CL1 (Fractalkine) and CX3C chemokine receptor 1 in systemic sclerosis.

Systemic sclerosis (SSc) is a complex autoimmune disease characterized by fibrosis, vascular damage, and immune dysregulation. Fractalkine or chemokine (C-X3-C motif) ligand 1 (CX3CL1), a chemokine and adhesion molecule, along with its receptor CX3CR1, have been implicated in the inflammatory processes of SSc. CX3CL1 functions as both a chemoattractant and an adhesion molecule, guiding immune cell trafficking. This systematic review examines the role of CX3CL1 and its receptor CX3CR1 in the pathogenesis of SSc, with a focus on pulmonary and vascular complications. A systematic literature search was conducted across databases including PubMed, Scopus, and Web of Science from inception to November 2020. The search focused on studies investigating the CX3CL1/CX3CR1 axis in the context of SSc. The review identified elevated CX3CL1 expression in SSc patients, particularly in the skin and lungs, where CX3CR1 is expressed on infiltrating immune cells. Higher levels of CX3CL1 were correlated with the severity of interstitial lung disease in SSc patients, indicating a potential predictive marker for disease progression. CX3CR1-positive monocytes and NK cells were recruited to inflamed tissues, contributing to fibrosis and tissue damage. Animal studies showed that inhibition of the CX3CL1/CX3CR1 axis reduced fibrosis and improved vascular function. The CX3CL1/CX3CR1 axis plays a key role in immune cell recruitment and fibrosis in SSc. Elevated CX3CL1 levels are associated with lung and vascular complications, making it a potential biomarker for disease progression and a promising therapeutic target.

Tumor Necrosis Factor Receptors and C-C Chemokine Receptor-2 Positive Cells Play an Important Role in the Intraerythrocytic Death and Clearance of Babesia microti.

Babesia microti is an Apicomplexan parasite that infects erythrocytes and causes the tick-transmitted infection, babesiosis. B. microti can cause a wide variety of clinical manifestations ranging from asymptomatic to severe infection and death. Some risk factors for severe disease are well-defined, an immune compromised state, age greater than 50, and asplenia. However, increasing cases of severe disease and hospitalization in otherwise healthy individuals suggests that there are unknown risk factors. The immunopathology of babesiosis is poorly described. CD4+ T cells and the spleen both play a critical role in parasite clearance, but few other factors have been found that significantly impact the course of disease. Here, we evaluated the role of several immune mediators in B. microti infection. Mice lacking TNF receptors 1 and 2, the receptors for TNFα and LTα, had a higher peak parasitemia, reduced parasite killing in infected red blood cells (iRBCs), and delayed parasite clearance compared to control mice. Mice lacking CCR2, a chemokine receptor involved in the recruitment of inflammatory monocytes, and mice lacking NADPH oxidase, which generates superoxide radicals, demonstrated reduced parasite killing but had little effect on the course of parasitemia. These results suggest that TNFR-mediated responses play an important role in limiting parasite growth, the death of parasites in iRBCs, and the clearance of iRBCs, and that the parasite killing in iRBCs is being primarily mediated by ROS and inflammatory monocytes/macrophages. By identifying factors involved in parasite killing and clearance, we can begin to identify additional risk factors for severe infection and newer therapeutic interventions.

Concomitant Expression of CD39, CD69, and CD103 Identifies Antitumor CD8+ T Cells in Breast Cancer Implications for Adoptive Cell Therapy.

In cancer, an effective immune response involves the action of several different cell types, among which CD8 T cells play a major role as they can specifically recognize and kill cancer cells via the release of cytotoxic molecules and cytokines, being of major importance for adoptive cell transfer (ACT) of ex vivo expanded tumor-infiltrating lymphocytes (TILs). The inflammation resulting from the tumor growth attracts both activated and bystander T cells. For an effective antitumor response, the T cell must express a specific group of chemokine receptors and integrins which include CD103, CD39, CD69, and CD25. These markers had already been analyzed in various cancers, not including breast cancer and their subsequent subtypes, until now. To analyze, the key receptors on ex vivo expanded tumor-infiltrating lymphocytes in luminal A and luminal B breast cancer (BC) subtypes. We were successful in expanding TILs ex vivo using a standard TIL culture condition from a cohort study of 15 primary luminal A and luminal B breast cancer patients. Furthermore, we examined the expression of CD103, CD39, CD69, and CD25 biomarkers after the expansion by flow cytometry. We found that the information about the percentage of TILs obtainable after the ex vivo expansion is not associated to nor it is dependent on the heterogeneity of the TIL population before the expansion and does not differ by the molecular subtype (p>0.05). We also found that there is a major population of memory-resident antitumor CD8+CD103+CD39+ and CD8+CD103+ CD69+ TILs present in the stroma after the expansion when compared to CD4 immunosubtypes (p<0.0001). Only the CD8+CD103+CD39+ subpopulation was related to BC subtype (0.0009). Evidence from our study suggests that CD8 TILs present in the stroma of luminal A and luminal B breast cancer patients can be quantified and phenotyped by flow cytometry and be further expanded ex vivo. The immuno-phenotyping of these markers may be targeted to improve the success of immunotherapeutic approaches, such as adoptive cellular therapy (ACT) in patients with BC.

Combination of the chemokine receptor type 2 (CCR2) antagonist DMX-200 and candesartan for COVID-19: a randomised controlled trial

ObjectiveTo determine whether a chemokine receptor type 2 antagonist, DMX-200 (repagermanium), in combination with an angiotensin receptor blocker, candesartan, improves clinical outcomes in people with COVID-19.DesignProspective, multicentre, double-blind, placebo-controlled trial.SettingTen...

Microglia and monocyte-derived macrophages drive progression of pediatric high-grade gliomas and are transcriptionally shaped by histone mutations.

Pediatric high-grade gliomas (pHGGs), including hemispheric pHGGs and diffuse midline gliomas (DMGs), harbor mutually exclusive tumor location-specific histone mutations. Using immunocompetent de novo mouse models of pHGGs, we demonstrated that myeloid cells were the predominant infiltrating non-neoplastic cell population. Single-cell RNA sequencing (scRNA-seq), flow cytometry, and immunohistochemistry illustrated the presence of heterogeneous myeloid cell populations shaped by histone mutations and tumor location. Disease-associated myeloid (DAM) cell phenotypes demonstrating immune permissive characteristics were identified in murine and human pHGG samples. H3.3K27M DMGs, the most aggressive DMG, demonstrated enrichment of DAMs. Genetic ablation of chemokines Ccl8 and Ccl12 resulted in a reduction of DAMs and an increase in lymphocyte infiltration, leading to increased survival of tumor-bearing mice. Pharmacologic inhibition of chemokine receptors CCR1 and CCR5 resulted in extended survival and decreased myeloid cell infiltration. This work establishes the tumor-promoting role of myeloid cells in DMG and the potential therapeutic opportunities for targeting them.

P2.14B.02 Application of Chemokine Receptor 4 Targeted 68Ga Pentixafor in Evaluation of Thymic Epithelial Tumors (TETs): A Prospective Study

P2.14B.02 Application of Chemokine Receptor 4 Targeted 68Ga Pentixafor in Evaluation of Thymic Epithelial Tumors (TETs): A Prospective Study