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Veterinary Immunology and... Jun 2024Polymorphonuclear cells (PMN) provide a rapid response to infection and tissue damage and stress can modify these critical innate immune defences. The study of...
Polymorphonuclear cells (PMN) provide a rapid response to infection and tissue damage and stress can modify these critical innate immune defences. The study of adrenergic receptor (AR) expression and function in bovine PMNs is limited but both neutrophils and eosinophils express numerous AR genes but differ significantly in their expression of individual AR genes. A flow cytometric technique was developed to differentiate between bovine neutrophils and eosinophils so both neutrophil and eosinophil responses to adrenergic agonists could be analysed. Neutrophils and eosinophils displayed significantly different changes in CD11b, L-selectin, and CD44 expression when activated by bovine serum opsonized zymosan and recombinant bovine interferon gamma. The responses of activated and resting neutrophils and eosinophils were then compared following stimulation with endogenous adrenergic agonists, epinephrine (E) norepinephrine (NE), and synthetic agonists targeting α1-, α2-, or β-ARs. Both resting and activated neutrophils and eosinophils displayed differences in iROS, CD44, and L-selectin expression following stimulation with E and NE. Resting neutrophils displayed pro-inflammatory responses to both E and NE, while resting eosinophils displayed a pro-inflammatory response to only NE. No single synthetic adrenergic agonist fully recapitulated responses observed with either E or NE and responses to adrenergic agonists were dose-dependent. In conclusion, bovine eosinophils and neutrophils responded to multiple adrenergic agonists by altering expression of proteins involved in immune surveillance and pro-inflammatory responses. Significant differences in neutrophil and eosinophil responses to adrenergic agonists are consistent with their differences in AR gene expression. This highlights the importance of analysing separately these two PMN subpopulations when investigating the effects of either endogenous or synthetic AR agonists.
Topics: Animals; Cattle; Neutrophils; Eosinophils; L-Selectin; Norepinephrine; Epinephrine; Adrenergic Agonists; Hyaluronan Receptors; Flow Cytometry; CD11b Antigen; Neutrophil Activation; Receptors, Adrenergic
PubMed: 38669937
DOI: 10.1016/j.vetimm.2024.110758 -
Archives of Gynecology and Obstetrics Jul 2024Spontaneous previable rupture of membranes complicates approximately 0.4-0.7% of pregnancies and is associated with severe maternal and neonatal morbidity and mortality.... (Review)
Review
Spontaneous previable rupture of membranes complicates approximately 0.4-0.7% of pregnancies and is associated with severe maternal and neonatal morbidity and mortality. Intra-amniotic inflammation is present in up to 94.4% of cases, most often caused by a bacterial infection. In comparison, the effectiveness of antibiotic therapy in its eradication reaches less than 17%. Inflammatory activity in the amniotic cavity disrupts the physiological development of the fetus with an increase in maternal, fetal, and neonatal inflammatory morbidity through the development of fetal inflammatory response syndrome, maternal chorioamnionitis, and neonatal sepsis. Amniopatch is an invasive therapeutic technique based on intra-amniotic administration of maternal hemoderivates in the form of thromboconcentrate and plasma cryoprecipitate to provide the temporary closure of the fetal membranes defect and secondary restitution of normohydramnios with correction of pressure-volume ratios. The supposed basis of this physical-mechanical action is the aggregation of coagulant components of amniopatch in the area of the defect with the formation of a valve cap. The background for the formulation of the hypothesis on the potential anti-infectious and anti-inflammatory action of non-coagulant components of amniopatch involved: i) clinical-academic and publishing outputs of the authors based on their many years' experience with amniopatch application in the treatment of spontaneous previable rupture of membranes (2008-2019), ii) the documented absence of clinically manifested chorioamnionitis in patients treated this way with a simultaneously reduced incidence of neonatal respiratory distress syndrome compared to expectant management (tocolysis, corticotherapy, antibiotic therapy). The non-coagulant components of plasma cryoprecipitate include mainly naturally occurring isohemagglutinins, albumin, and soluble plasma fibrinogen. Although these components of the amniopatch have not been attributed a significant therapeutic role, the authors assume that due to their opsonizing and aggregative properties, they can significantly participate in optimizing the intrauterine environment through the reduction in bacterial and cytokine charge in the amniotic fluid. The authors think these facts constitute a vital stimulus to future research-academic activity and, at the same time, an idea for reconsidering the therapeutic role of amniopatch as a tool for improving perinatal results of spontaneous previable ruptures of membranes.
Topics: Humans; Pregnancy; Female; Fetal Membranes, Premature Rupture; Fibrinogen; Chorioamnionitis; Anti-Inflammatory Agents; Infant, Newborn; Anti-Infective Agents; Factor VIII
PubMed: 38642127
DOI: 10.1007/s00404-024-07399-0 -
Journal of Clinical Tuberculosis and... May 2024Antimicrobial resistance alongside other challenges in tuberculosis (TB) therapeutics have stirred renewed interest in host-directed interventions, including the role of...
Antimicrobial resistance alongside other challenges in tuberculosis (TB) therapeutics have stirred renewed interest in host-directed interventions, including the role of antibodies as adjunct therapeutic agents. This study assessed the binding efficacy of two novel IgG1 opsonic monoclonal antibodies (MABs; GG9 & JG7) at 5, 10, and 25 µg/mL to live cultures of , , , , and American Type Culture Collection laboratory reference strains, as well as clinical susceptible, multi-drug resistant, and extensively drug resistant strains using indirect enzyme-linked immunosorbent assays. These three MAB concentrations were selected from a range of concentrations used in previous optimization (binding and functional) assays. Both MABs bound to all mycobacterial species and sub-types tested, albeit to varying degrees. Statistically significant differences in MAB binding activity were observed when comparing the highest and lowest MAB concentrations (p < 0.05) for both MABs GG9 and JG7, irrespective of the resistance profile. Binding affinity increased with an increase in MAB concentration, and optimal binding was observed at 25 µg/mL. JG7 showed better binding activity than GG9. Both MABs also bound to five MOTT species, albeit at varied levels. This non-selective binding to different mycobacterial species suggests a potential role for GG9 and JG7 as adjunctive agents in anti-TB chemotherapy with the aim to enhance bacterial killing.
PubMed: 38601919
DOI: 10.1016/j.jctube.2024.100435 -
Advanced Science (Weinheim,... Jun 2024Osteoarthritis (OA) is a chronic inflammatory disease characterized by cartilage destruction, synovitis, and osteophyte formation. Disease-modifying treatments for OA...
Osteoarthritis (OA) is a chronic inflammatory disease characterized by cartilage destruction, synovitis, and osteophyte formation. Disease-modifying treatments for OA are currently lacking. Because inflammation mediated by an imbalance of M1/M2 macrophages in the synovial cavities contributes to OA progression, regulating the M1 to M2 polarization of macrophages can be a potential therapeutic strategy. Basing on the inherent immune mechanism and pathological environment of OA, an immunoglobulin G-conjugated bilirubin/JPH203 self-assembled nanoparticle (IgG/BRJ) is developed, and its therapeutic potential for OA is evaluated. After intra-articular administration, IgG conjugation facilitates the recognition and engulfment of nanoparticles by the M1 macrophages. The internalized nanoparticles disassemble in response to the increased oxidative stress, and the released bilirubin (BR) and JPH203 scavenge reactive oxygen species (ROS), inhibit the nuclear factor kappa-B pathway, and suppress the activated mammalian target of rapamycin pathway, result in the repolarization of macrophages and enhance M2/M1 ratios. Suppression of the inflammatory environment by IgG/BRJ promotes cartilage protection and repair in an OA rat model, thereby improving therapeutic outcomes. This strategy of opsonization involving M1 macrophages to engulf carrier-free BR/JPH203 nanoparticles to suppress inflammation for OA therapy holds great potential for OA intervention and treatment.
Topics: Animals; Osteoarthritis; Macrophages; Nanoparticles; Rats; Disease Models, Animal; Inflammation; Bilirubin; Male; Rats, Sprague-Dawley
PubMed: 38593402
DOI: 10.1002/advs.202400713 -
Scientific Reports Apr 2024Natural killer (NK) cells destroy tissue that have been opsonized with antibodies. Strategies to generate or identify cells with increased potency are expected to...
Natural killer (NK) cells destroy tissue that have been opsonized with antibodies. Strategies to generate or identify cells with increased potency are expected to enhance NK cell-based immunotherapies. We previously generated NK cells with increased antibody-dependent cell mediated cytotoxicity (ADCC) following treatment with kifunensine, an inhibitor targeting mannosidases early in the N-glycan processing pathway. Kifunensine treatment also increased the antibody-binding affinity of Fc γ receptor IIIa/CD16a. Here we demonstrate that inhibiting NK cell N-glycan processing increased ADCC. We reduced N-glycan processing with the CRIPSR-CAS9 knockdown of MGAT1, another early-stage N-glycan processing enzyme, and showed that these cells likewise increased antibody binding affinity and ADCC. These experiments led to the observation that NK cells with diminished N-glycan processing capability also revealed a clear phenotype in flow cytometry experiments using the B73.1 and 3G8 antibodies binding two distinct CD16a epitopes. We evaluated this "affinity profiling" approach using primary NK cells and identified a distinct shift and differentiated populations by flow cytometry that correlated with increased ADCC.
Topics: Humans; Receptors, IgG; Flow Cytometry; Killer Cells, Natural; Antibody-Dependent Cell Cytotoxicity; Polysaccharides
PubMed: 38575779
DOI: 10.1038/s41598-024-58541-6 -
Experimental Hematology & Oncology Mar 2024VISTA is a well-known immune checkpoint in T cell biology, but its role in innate immunity is less established. Here, we investigated the role of VISTA on anticancer...
BACKGROUND
VISTA is a well-known immune checkpoint in T cell biology, but its role in innate immunity is less established. Here, we investigated the role of VISTA on anticancer macrophage immunity, with a focus on phagocytosis, macrophage polarization and concomitant T cell activation.
METHODS
Macrophages, differentiated from VISTA overexpressed THP-1 cells and cord blood CD34 cell-derived monocytes, were used in phagocytosis assay using B lymphoma target cells opsonized with Rituximab. PBMC-derived macrophages were used to assess the correlation between phagocytosis and VISTA expression. qRT-PCR, flow cytometry, and enzyme-linked immunosorbent assay were performed to analyze the impact of VISTA on other checkpoints and M1/M2-like macrophage biology. Additionally, flow cytometry was used to assess the frequency of CD14 monocytes expressing VISTA in PBMCs from 65 lymphoma patients and 37 healthy donors.
RESULTS
Ectopic expression of VISTA in the monocytic model cell line THP-1 or in primary monocytes triggered differentiation towards the macrophage lineage, with a marked increase in M2-like macrophage-related gene expression and decrease in M1-like macrophage-related gene expression. VISTA expression in THP-1 and monocyte-derived macrophages strongly downregulated expression of SIRPα, a prominent 'don't eat me' signal, and augmented phagocytic activity of macrophages against cancer cells. Intriguingly, expression of VISTA's extracellular domain alone sufficed to trigger phagocytosis in ∼ 50% of cell lines, with those cell lines also directly binding to recombinant human VISTA, indicating ligand-dependent and -independent mechanisms. Endogenous VISTA expression was predominantly higher in M2-like macrophages compared to M0- or M1-like macrophages, with a positive correlation observed between VISTA expression in M2c macrophages and their phagocytic activity. VISTA-expressing macrophages demonstrated a unique cytokine profile, characterized by reduced IL-1β and elevated IL-10 secretion. Furthermore, VISTA interacted with MHC-I and downregulated its surface expression, leading to diminished T cell activation. Notably, VISTA surface expression was identified in monocytes from all lymphoma patients but was less prevalent in healthy donors.
CONCLUSIONS
Collectively, VISTA expression associates with and drives M2-like activation of macrophages with a high phagocytic capacity yet a decrease in antigen presentation capability to T cells. Therefore, VISTA is a negative immune checkpoint regulator in macrophage-mediated immune suppression.
PubMed: 38553748
DOI: 10.1186/s40164-024-00501-x -
Cells Mar 2024Disulfiram (DSF), an anti-alcoholism medicine, exerts treatment effects in patients suffering from persistent Borreliosis and also exhibits anti-cancer effects through...
Disulfiram (DSF), an anti-alcoholism medicine, exerts treatment effects in patients suffering from persistent Borreliosis and also exhibits anti-cancer effects through its copper chelating derivatives and induction of oxidative stress in mitochondria. Since chronic/persistent borreliosis is characterized by increased amounts of pro-inflammatory macrophages, this study investigated opsonin-independent phagocytosis, migration, and surface marker expression of in vivo activated and in vitro cultured human monocyte-derived phagocytes (macrophages and dendritic cells) with and without DSF treatment. Phagocytosis of non-opsonized Dynabeads M-450 and migration of macrophages and dendritic cells were monitored using live cell analyzer Juli™ Br for 24 h, imaging every 3.5 min. To simultaneously monitor phagocyte function, results were analyzed by a newly developed software based on the differential phase contrast images of cells before and after ingestion of Dynabeads. DSF decreased the phagocytic capacities exhibited by in vitro enriched and long-lived phagocytes. Although no chemotactic gradient was applied to the test system, vigorous spontaneous migration was observed. We therefore set up an algorithm to monitor and quantify both phagocytosis and migration simultaneously. DSF not only reduced phagocytosis in a majority of these long-lived phagocytes but also impaired their migration. Despite these selective effects by DSF, we found that DSF reduced the expression densities of surface antigens CD45 and CD14 in all of our long-lived phagocytes. In cells with a high metabolic activity and high mitochondrial contents, DSF led to cell death corresponding to mitochondrial oxidative stress, whereas metabolically inactive phagocytes survived our DSF treatment protocol. In conclusion, DSF affects the viability of metabolically active phagocytes by inducing mitochondrial stress and secondly attenuates phagocytosis and migration in some long-lived phagocytes.
Topics: Humans; Disulfiram; Opsonin Proteins; Phagocytosis; Phagocytes; Macrophages
PubMed: 38534379
DOI: 10.3390/cells13060535 -
Frontiers in Cellular and Infection... 2024is an important human opportunistic pathogen responsible for a wide range of infections. The complement system is the main early host defense mechanism to control these...
is an important human opportunistic pathogen responsible for a wide range of infections. The complement system is the main early host defense mechanism to control these infections. counteracts complement attack by binding Factor H (FH), a complement regulator that inactivates C3b, preventing the formation of the C3-convertase and complement amplification on the bacterial surface. Factor H-related proteins (FHRs) are a group of plasma proteins evolutionarily related to FH that have been postulated to interfere in this bacterial mechanism of resisting complement. Here, we show that FHR-1 binds to via the outer membrane protein OprG in a lipopolysaccharide (LPS) O antigen-dependent manner. Binding assays with purified components or with FHR-1-deficient serum supplemented with FHR-1 show that FHR-1 competes with FH for binding to Blockage of FH binding to C3b deposited on the bacteria reduces FH-mediated cofactor activity of C3b degradation, increasing the opsonization of the bacteria and the formation of the potent chemoattractant C5a. Overall, our findings indicate that FHR-1 is a host factor that promotes complement activation, facilitating clearance of by opsonophagocytosis.
Topics: Humans; Complement Factor H; Pseudomonas aeruginosa; Opsonization; Protein Binding; Complement System Proteins; Bacteria; Blood Proteins
PubMed: 38510967
DOI: 10.3389/fcimb.2024.1328185 -
Revista Espanola de Enfermedades... Mar 2024Vaccination in patients with advanced chronic liver disease (ACLD) is an essential part of their comprehensive healthcare. These individuals may have impaired phagocytic...
Vaccination in patients with advanced chronic liver disease (ACLD) is an essential part of their comprehensive healthcare. These individuals may have impaired phagocytic function and diminished production of opsonizing antibodies, resulting in increased susceptibility to bacterial infections, particularly pneumococcal pneumonia. Similarly, there is an increased risk of fulminant hepatitis due to hepatitis A and B viruses. The Ministry of Health updated specific vaccination recommendations for this group in 2018.
PubMed: 38501772
DOI: 10.17235/reed.2024.10386/2024 -
JHEP Reports : Innovation in Hepatology Apr 2024Hepatocellular necrosis is common in both acute and chronic liver injury and may evolve to fibrosis and liver failure. Injury leads to accumulation of necrotic cell...
BACKGROUND & AIMS
Hepatocellular necrosis is common in both acute and chronic liver injury and may evolve to fibrosis and liver failure. Injury leads to accumulation of necrotic cell debris in the liver, which drives persistent inflammation and poor recovery. This study investigated the role of natural antibodies (NAbs) in the clearance of necrotic cells in the injured liver, their impact on tissue regeneration and their potential as a therapy for acute liver injury.
METHODS
We used murine models of drug-induced liver injury and focal thermal injury in immunocompetent and antibody-deficient mice ( and IgMi). Intravital microscopy was used to investigate the role of NAbs in the phagocytosis of necrotic cells in the liver . Immunostainings were used to quantify the extent of liver necrosis (fibrin), antibody deposition (IgM and IgG) and cellular proliferation (Ki67).
RESULTS
Both IgM and IgG NAbs bound necrotic liver areas and opsonized multiple debris molecules released during hepatocellular necrosis such as DNA, histones, actin, phosphoinositides and mitochondrial cardiolipin, but not phosphatidylserine. and IgMi mice presented impaired recovery from liver injury, which was correlated to the sustained presence of necrotic debris in the tissue, prolonged inflammation and reduced hepatocellular proliferation. These defects were rescued by treating mice with NAbs after the induction of injury. Mechanistically, and , phagocytosis of necrotic debris was dependent on NAbs via Fcγ receptors and CD11b. Moreover, NAb-mediated phagocytosis of necrotic cell debris occurs in two waves, firstly driven by neutrophils and then by recruited monocytes. Importantly, supplementation of immunocompetent mice with NAbs also improved liver regeneration significantly, demonstrating the therapeutic potential of natural IgM and IgG.
CONCLUSION
NAbs drive the phagocytosis of necrotic cells in liver injury and promote liver regeneration and recovery.
IMPACT AND IMPLICATIONS
Treatment with natural antibodies after acute liver injury improved recovery by increasing the clearance of necrotic debris and by improving cellular proliferation in the liver. This preclinical study provides a basis for the development of an immunotherapy for patients with early-stage, reversible, liver injury that aims to prevent disease chronification into fibrosis and liver failure.
PubMed: 38481390
DOI: 10.1016/j.jhepr.2024.101013