Granulocyte Function Research Articles

Effects of Pressure, Hypoxia, and Hyperoxia on Neutrophil Granulocytes

Background: The application of normo- and hyperbaric O2 is a common therapy option in various disease patterns. Thereby, the applied O2 affects the whole body, including the blood and its components. This study investigates influences of pressure and oxygen fraction on human blood plasma, nutrient media, and the functions of neutrophil granulocytes (PMNs). Methods: Neutrophil migration, reactive oxygen species (ROS) production, and NETosis were examined by live cell imaging. The treatment of various matrices (Roswell Park Memorial Institute 1640 medium, Dulbecco’s Modified Eagle’s Medium, H2O, human plasma, and isolated PMNs) with hyperbaric oxygen (HBO) was performed. In addition, the expression of different neutrophil surface epitopes (CD11b, CD62L, CD66b) and the oxidative burst were investigated by flow cytometry (FACS). The application of cold atmospheric plasma (CAP) to normoxic and normobaric culture media served as a positive control. Soluble reaction products such as H2O2, reactive nitrogen species (RNS: NO2− and NO3−), and ROS-dependent dihydrorhodamine oxidation were quantified by fluoro- and colorimetric assay kits. Results: Under normobaric normoxia, PMNs migrate slower and shorter in comparison with normobaric hyper- or hypoxic conditions and hyperbaric hyperoxia. The pressure component has less effect on the migration behavior of PMNs than the O2 concentration. Individual PMN cells produce prolonged ROS at normoxic conditions. PMNs showed increased expression of CD11b in normobaric normoxia, lower expression of CD62L in normobaric normoxia, and lower expression of CD66b after HBO and CAP treatment. Treatment with CAP increased the amount of ROS and RNS in common culture media. Conclusions: Hyperbaric and normobaric O2 influences neutrophil functionality and surface epitopes in a measurable way, which may have an impact on disorders with neutrophil involvement. In the context of hyperbaric experiments, especially high amounts of H2O2 in RPMI after hyperbaric oxygen should be taken into account. Therefore, our data support a critical indication for the use of normobaric and hyperbaric oxygen and conscientious and careful handling of oxygen in everyday clinical practice.

Human cytomegalovirus infection among febrile hematological cancer patients at the Uganda Cancer Institute

ABSTRACT Hematological cancers, including Leukemias and Lymphomas, and their associated chemotherapy and disease-specific factors, are linked to impaired granulocyte function and numbers, increasing the risk of opportunistic infections, often presenting as fever. Human cytomegalovirus (HCMV) is one of the significant opportunistic infections in these patients, but limited data exists on its seroprevalence and active infection burden among febrile hematological cancer patients in Uganda. We conducted a cross-sectional study from June to August 2017 at the Uganda Cancer Institute (UCI). Blood samples from 161 febrile hematological cancer patients were collected. HCMV exposure was assessed using indirect enzyme-linked immunosorbent assay for IgG and IgM antibodies, and active infection was confirmed with PCR testing and gel electrophoresis. IgG positivity indicated previous exposure, while positive IgM or PCR results indicated active infection. Overall, HCMV seroprevalence based on IgG and/or IgM positivity was 106/161 (66%). IgG alone, IgM alone, and combined IgG/IgM positivity prevalence rates were 57/161 (35.4%), 22/161 (13.6%), and 27/161 (16.7%), respectively. HCMV DNA PCR was positive in 5 of the 161 (3%) samples. Among PCR-positive patients, one (20%) was positive for IgG alone, two (40%) for IgM alone, and two (40%) for both IgG and IgM. Active infection based on positive IgM and HCMV DNA PCR was found in 23 of the 161 (14.3%) patients. Two-thirds of febrile patients with hematological malignancies in Uganda had been exposed to HCMV infection, with 14.3% showing active infection. Routine testing for active HCMV infection among febrile hematological cancer patients at the UCI is essential for timely and appropriate antiviral treatment. IMPORTANCE In this paper, we demonstrated that over two-thirds of feverish patients with blood cancers such as leukemia at the Uganda Cancer Institute are already exposed to a type of virus infection called the human cytomegalovirus (HCMV), and 14% of the patients have active disease due to this virus. This was confirmed through finding blood samples testing positive for a type of protective antibody called IgM and also upon virus DNA detection in the blood of those patients. Routine testing for this virus is not usually done in the study settings. Our findings reveal and emphasize the importance of routinely testing blood samples for active infection with this virus among the feverish patients with blood cancers in the study settings, and prompt initiation of antiviral treatment of the actively infected patients

MicroRNA Profiles in Hematopoietic Stem Cell Transplant Recipients.

Background: Hematopoietic Stem Cell Transplant (HCT) is a potentially curative treatment for hematologic malignancies, including multiple myeloma. Biomarker investigation can guide identification of HCT recipients at-risk for poor outcomes. MicroRNAs (miRNAs) are a class of non-coding RNAs involved in the modulation and regulation of pathological processes and are emerging as prognostic and predictive biomarkers for multiple health conditions. This pilot study aimed to examine miRNA profiles associated with HCT-related risk factors and outcomes in patients undergoing autologous HCT. Methods: Patients eligible for autologous HCT were recruited and blood samples and HCT-related variables were collected. Differential expression analysis of miRNA was conducted on 24 patient samples to compare changes in miRNA profile in HCT eligible patients before and after transplant. Results: Unsupervised clustering of differentially expressed (p < .05) miRNAs pre- and post- HCT identified clusters of up- and down-regulated miRNAs. Four miRNAs (miR-125a-5p, miR-99b-5p, miR-382-5p, miR-145-5p) involved in hematopoiesis (differentiation of progenitor cells, granulocyte function, thrombopoiesis, and tumor suppression) were significantly downregulated post-HCT. Correlation analyses identified select miRNAs associated with risk factors (such as frailty, fatigue, cognitive decline) and quality of life pre- and post-HCT. Select miRNAs were correlated with platelet engraftment. Conclusion: Future studies should examine miRNA signatures in larger cohorts in association with HCT outcomes; and expand investigations in patients receiving allogeneic transplants. This will lead to identification of biomarkers for risk stratification of HCT recipients.

COLD INHIBITION OF BIOACTIVITY OF PROBIOTIC MYCOBACTERIA AND AEROCOCCI IN THE MICROBIOME

The organism of farm animals is constantly under the influence of various factors of the external environment, and one of the negative factors of violation of the technology of keeping and creation of unsatisfactory conditions of existence with deterioration of well-being is cold injury. Mostly it manifests itself as a permanent effect of positive temperatures well below the physiological norm or periodic fluctuations of an uncomfortable temperature. Such a stress factor of low intensity, but permanent over a long period of time, causes negative pathophysiological changes in the macroorganism with the development of immune-depression, metabolic syndrome, perversions of the qualitative composition of the microbiome and, as a result, disruption of native physiological processes of stimulation of cellular mechanisms of nonspecific innate immunity, induced by immune-biological mechanisms of the functioning of neutrophil granulocytes. The negative effect of low-intensity permanent cold stress was studied on a model object - murchakаs, which were kept for two weeks at a temperature of 4-6 °C under conditions of light and movement restriction. Before the start of the experiment, initial microbiological studies of the microbiome of the large intestine were conducted using generally accepted methods. Resident indigenous probiotic prokaryotes - M. vaccae &amp; A. viridans, which possessed typical species characteristics, were isolated. Pathogenic variants of enterobacteria were not isolated, isolated cultures of E. coli were apathogenic and belonged to the usual normal flora. A two-week cold injury resulted in the disappearance of the indigenous probiotic microbiota M. vaccae &amp; A. viridans, which are indicator prokaryotes of the physiological well-being of the macroorganism, from the microbiome. At the same time, the number of potentially pathogenic enteral microorganisms, coccal and rod-shaped, increased. This was correlated with a decrease in the phagocytic activity of native neutrophil granulocytes and their preformed filamentous spatial nucleoprotective mesh structures, which inhibit the de-fragmentary function in relation to genetically non-syngenic objects.

Pharmacological evidence that the inhibitory effects of prostaglandin E2 are mediated by the EP2 and EP4 receptors in human neutrophils.

Prostaglandin E2 (PGE2) is a recognized inhibitor of granulocyte functions. However, most of the data supporting this was obtained when available pharmacological tools mainly targeted the EP2 receptor. Herein, we revisited the inhibitory effect of PGE2 on reactive oxygen species production, leukotriene biosynthesis, and migration in human neutrophils. Our data confirm the inhibitory effect of PGE2 on these functions and unravel that the effect of PGE2 on human neutrophils is obtained by the combined action of EP2 and EP4 agonism. Accordingly, we also demonstrate that the inhibitory effect of PGE2 is fully prevented only by the combination of EP2 and EP4 receptor antagonists, underscoring the importance of targeting both receptors in the effect of PGE2. Conversely, we also show that the inhibition of ROS production by human eosinophils only involves the EP4 receptor, despite the fact that they also express the EP2 receptor.

&lt;i&gt;In vitro&lt;/i&gt; effects of recombinant IFNα2B on the content of antigen-presenting CD66b&lt;sup&gt;+&lt;/sup&gt;CD16&lt;sup&gt;+&lt;/sup&gt;CD33&lt;sup&gt;+&lt;/sup&gt;HLA&lt;sup&gt;-&lt;/sup&gt;DR&lt;sup&gt;+&lt;/sup&gt; subset of neutrophils in children with acute osteomyelitis

Negative impact of S. aureus, seems to be a sufficient condition for the spread of the infectious process in the bone in acute osteomyelitis (AOM) due to its altered elimination caused by dysfunction of the immune system (IS), in particular, of neutrophilic granulocytes (NG). Correction of NG dysfunction in AOM under the influence of immunotropic substances and cytokines via modulation of the NG phenotypic subsets is of sufficient interest. Our aim was to evaluate the in vitro effects of recombinant IFNá2b on the number and phenotype of CD66b+CD16+CD33+HLA-DR-, CD66b+CD16+CD33+HLA-DR+ subsets and on phagocytic function of neutrophilic granulocytes in acute osteomyelitis in children.&#x0D; The study of peripheral blood (PB) samples from children aged 8-15 years was carried out as follows: patients with АOM (n = 24) comprised study group 1 (SG1), healthy children (n = 13) were included into comparison group (CG). PB samples of children with AOM were incubated with recIFNá2b (50 IU/µL, 60 min, 37 °C.) in the study group 1a (SG1a). Before and after incubation with recIFNá2b, the number of NG subsets CD66b+CD16+CD33+HLA-DR-, CD66b+CD16+CD33+HLA-DR+ and the density values of receptor expression by fluorescence intensity (MFI) were also determined (FC 500, Beckman Coulter, США). Phagocytic activity of NCs was evaluated as the contents of actively phagocytic NCs (%PhAN), volume of the engulfed S. aureus (strain 209) by assessing their phagocytic number (PhN), phagocytic index (PhI). Bacterial killing was determined as the percentages of microbe digestion (%D), digestion index (DI).&#x0D; The cells from AOM patients revealed a subset expressing the HLA-DR receptor – СD66b+CD16+CD33+HLA-DR+NG, which is absent in the PB of CG children. The cells with primed phenotype exhibited an increased expression density of activation receptors CD16 and CD66b. Incubation of PB in AOM with recIFNá2b led to an increased proportion of CD66b+CD16+CD33+HLA-DR+ NG subset which showed active phagocytosis and improved digestion processes. The present study shows the emergence of activated subset of “long-lived” CD66b+CD16+CD33+HLA-DR+ NCs in children with AOM. This subpopulation has APC features, by presenting AG to T lymphocytes, with preserved effector properties. In an in vitro experimental system, a positive effect of recIFNá2b was demonstrated, leading to an increased number of NGs of the CD66b+CD16+CD33+HLA-DR+ subset and recovery of S. aureus phagocytosis by NGs, thus being promising in the future for development of new approaches to optimization of complex therapy in the postoperative period of AOM treatment, prevention of complications and the opportunity to alleviate the disorders in the immune system.

Positive effects of recombinant interferon α2b on the phenotype of CD16&lt;sup&gt;+&lt;/sup&gt;INFα/βR1&lt;sup&gt;-&lt;/sup&gt;CD119&lt;sup&gt;+&lt;/sup&gt;, CD16&lt;sup&gt;+&lt;/sup&gt;INFα/βR1&lt;sup&gt;+&lt;/sup&gt;CD119&lt;sup&gt;-&lt;/sup&gt; neutrophil granulocyte subset in patients with post-COVID syndrome and herpesvirus infections

Post-COVID syndrome (PCS) is a multisystem inflammatory condition with manifestations of chronic fatigue syndrome (CFS) and cognitive disorders (CD), along with reactivation of chronic herpesvirus infections (HVI). The PCS manifestations require studying the molecular mechanisms associated with the production of IFN and receptor functions of neutrophil granulocytes (NG), which is relevant and promotes the search for immunotherapeutic strategies in patients with PCS. Our objective was to study the in vitro effects of recombinant interferon α2b (recIFNα2b) on the phenotype of CD16+IFNα/βR1-CD119+, CD16+IFNα/ βR1+CD119+ subsets and functional activity of NG in patients with post-COVID syndrome and herpesvirus infections. Materials and methods: 45 patients (24-60 years old) with PCS and HVI (HSV 1, EBV, HHV6, CMV) comprised the study group 1 (SG1). A questionnaire was conducted to assess the severity of PCS symptoms using a point scale. We performed a study of the content and phenotype of NG subsets, i.e., the CD16+IFNα/βR1-CD119+, CD16+IFNα/βR1+CD119-, CD16+IFNα/βR1+CD119+ subpopulation, phagocytic and NADPH oxidase function of NG before and after in vitro incubation with recIFNα2b (50 IU/ µL, for 60 min, at 37 °C) in the study group 1a (SG1a). The comparison group (CG) of 30 volunteers examined during the pre-COVID period. Results: We revealed more pronounced clinical manifestations of CFS and CD in SG1 patients with mixed HVI, than in mono-HVI cases. Increased expression density of all receptors was registered on CD16+IFNα/βR1+CD119-NG and CD16+IFNα/βR1-CD119+ NG, thus suggesting the NG activation with initiation of cytotoxicity or NETosis, a decrease in phagocytic function and intensity of NADPH oxidase activity with depletion of NG reserve capacity in SG1. We have obtained some data on the positive effect of recIFNα2b in vitro (SG1a), e.g., decreased CD16 expression density and enhancement of IFNα/βR1 receptor expression in the CD16+IFNα/βR1+CD119- subset. In the CD16+IFNα/βR1-CD119+ subset, we have found persistence of increased MFI CD16 and MFI CD119 receptors, restoration of defective NG phagocytic function and reduced excessive activity of NADPH oxidases. Conclusion: The positive effects of the recIFNα2b influence on deficient function of NG in PCS patients suggest an oppoptunity of using immunotherapy with a recIFNα2b-based drug, combined with highly active antioxidants for treatment of various PCS manifestations including CFS, CD, HVI, thus, probably, ensuring adequate functioning of antiviral and regulatory mechanisms of the immune system.

Role of mTORC1 Signaling in Regulating the Immune Function of Granulocytes in Teleost Fish.

Granulocytes are crucial innate immune cells that have been extensively studied in teleost fish. Studies in mammals have revealed that mechanistic target of rapamycin complex 1 (mTORC1) signaling acts as a significant immune regulatory hub, influencing granulocyte immune function. To investigate whether mTORC1 signaling also regulates the immune function of granulocytes in teleost fish, we established a model of RAPA inhibition of the mTORC1 signaling pathway using granulocytes from largemouth bass (Micropterus salmoides). Our results demonstrated that inhibition of mTORC1 signaling promoted autophagy and apoptosis of granulocytes while inhibiting cell proliferation. Moreover, inhibition of the mTORC1 signaling pathway enhanced the phagocytosis capacity of granulocytes. Collectively, our findings revealed the evolutionarily conserved role of the mTORC1 signaling pathway in regulating granulocyte responses, thus providing novel insights into the function of granulocytes in teleost fish.

Recovery of the Decreased Phagocytic Function of Peripheral Monocytes and Neutrophil Granulocytes following Cytoreductive Surgery in Advanced Stage Epithelial Ovarian Cancer.

(1) Monocytes and neutrophil granulocytes are the phagocytic cells of the innate immune system, playing a crucial role in recognizing and eliminating tumor-transformed cells. Our objective was to assess the impact of advanced-stage epithelial ovarian cancer (EOC) and cytoreductive surgery on the phagocytic function of peripheral monocytes and neutrophil granulocytes. We aimed to compare the pre- and postoperative phagocytic function of these immune cells in EOC patients with healthy control women. Additionally, we aimed to examine the influence of surgery on phagocytic function by comparing pre- and postoperative samples from patients with benign gynecological tumors. (2) We examined peripheral blood samples from 20 patients with FIGO IIIC stage high-grade serous EOC and 16 patients with benign gynecological tumors as surgical controls, collected before and seven days after tumor removal surgery, and from 14 healthy women. After separation, the cells were incubated with Zymosan-A particles, and the phagocytic index (PI) was assessed using immunofluorescence microscopy. One-way ANOVA, the Kruskal-Wallis H-test, and the paired samples t-test were used for the statistical analysis of the data. A significance level of p < 0.05 was applied. (3) Peripheral monocytes and neutrophils from EOC patients exhibited significantly lower preoperative PI values compared to healthy controls (p < 0.001; p < 0.001, respectively). Following cytoreductive surgery, the PI values of immune cells in EOC patients significantly increased by the 7th postoperative day (p < 0.001; p < 0.001), reaching levels comparable to those of healthy controls (p = 0.700 and p = 0.991). In contrast, there was no significant disparity in the PI values of cells obtained from pre- and postoperative blood samples of surgical controls when compared to healthy women (monocytes: p = 0.361 and p = 0.303; neutrophils: p = 0.150 and p = 0.235). (4) EOC and/or its microenvironment may produce factors that reduce the phagocytic function of monocytes and neutrophils, and the production of these factors may be reduced or eliminated after tumor removal.

Role of Mitochondria in the Regulation of Effector Functions of Granulocytes.

Granulocytes (neutrophils, eosinophils, and basophils) are the most abundant circulating cells in the innate immune system. Circulating granulocytes, primarily neutrophils, can cross the endothelial barrier and activate various effector mechanisms to combat invasive pathogens. Eosinophils and basophils also play an important role in allergic reactions and antiparasitic defense. Granulocytes also regulate the immune response, wound healing, and tissue repair by releasing of various cytokines and lipid mediators. The effector mechanisms of granulocytes include the production of reactive oxygen species (ROS), degranulation, phagocytosis, and the formation of DNA-containing extracellular traps. Although all granulocytes are primarily glycolytic and have only a small number of mitochondria, a growing body of evidence suggests that mitochondria are involved in all effector functions as well as in the production of cytokines and lipid mediators and in apoptosis. It has been shown that the production of mitochondrial ROS controls signaling pathways that mediate the activation of granulocytes by various stimuli. In this review, we will briefly discuss the data on the role of mitochondria in the regulation of effector and other functions of granulocytes.

The Effects of Sodium Acetate on the Immune Functions of Peripheral Mononuclear Cells and Polymorphonuclear Granulocytes in Postpartum Dairy Cows.

Excessive lipid mobilization will snatch cell membrane lipids in postpartum dairy cows, which may impair the function of immune cells, including peripheral mononuclear cells (PBMCs) and polymorphonuclear granulocytes (PMNs). Acetate, as a precursor and the energy source of milk fat synthesis, plays a key role in lipid synthesis and the energy supply of dairy cows. However, there is little information about the effect of sodium acetate (NaAc) on the immune function of PBMC and PMN in postpartum dairy cows. Therefore, this study aimed to evaluate the effects of NaAc on the immune functions of PBMCs and PMNs in postpartum dairy cows. In this experiment, twenty-four postpartum multiparous Holstein cows were randomly selected and divided into a NaAc treatment group and a control group. Our results demonstrated that the dietary addition of NaAc increased (p < 0.05) the number of monocytes and the monocyte ratio, suggesting that these postpartum cows fed with NaAc may have better immunity. These expressions of genes (LAP, XBP1, and TAP) involved in the antimicrobial activity in PBMCs were elevated (p < 0.05), suggesting that postpartum dairy cows supplemented with NaAc had the ability of antimicrobial activity. In addition, the mRNA expression of the monocarboxylate transporters MCT1 and MCT4 in PBMCs was increased (p < 0.05) in diets supplemented with NaAc in comparison to the control. Notably, the expression of the XBP1 gene related to antimicrobial activity in PMN was upregulated with the addition of NaAc. The mRNA expression of genes (TLN1, ITGB2, and SELL) involved in adhesion was profoundly increased (p < 0.05) in the NaAc groups. In conclusion, our study provided a novel resolution strategy in which the use of NaAc can contribute to immunity in postpartum dairy cows by enhancing the ability of antimicrobial and adhesion in PBMCs and PMNs.

The effectiveness of immunomodulatory therapy with a synthetic analogue of the active center of the hormone thymus thymopoietin in the complex treatment of immunocompromised women with chronic infectious and inflammatory diseases of the pelvic organs

Chronic inflammatory diseases of the pelvic organs (pelvic inflammatory disease, PID) in women is among the main understudied problems in gynecology worldwide with adverse medical and socio-economic consequences, thus justifying the need for further study of immunopathogenesis and development of new approaches to treatment. Our objective was to develop new immunotherapeutic approaches to correction of combined disorders of the immune system functioning in immunocompromised women with PID and to evaluate their clinical and immunological efficacy.&#x0D; 55 women aged 20-40 years were examined, i.e., 35 patients with exacerbation of sluggish or recurrent PID, resistant to conventional therapy. Testiung was performed before complex treatment (study group 1 GI- 1) and after the course (study group 2 GI-2). Contents of T and B lymphocytes, natural killer cells (NK) (CYTOMICS FC500, USA), phagocytic and microbicidal functions of neutrophilic granulocytes (NG) were assessed in SG-1 and SG-2 before and 2-3 days after complex treatment with addition of an immunotherapeutic drug based on hexapeptide (HP) at a daily dose of 45 mg/ml intramuscularly for 10 days.&#x0D; In patients from SG-1, a decrease in T cells (CD3+CD19- ) and B cells (CD3-CD19+), a 2-fold increase in the content of NK CD3-CD16+CD56+ was found, along with altered functioning of NG (deficiency of actively phagocytizing NG, a decrease in their digestive function and NADPH-oxidase activity). In SG-2 patients, the treatment was followed by restoration of the T (CD3+CD19-) and B cells (CD3-CD19+), NK cells (CD3-CD16+CD56+), like as an increase in effector functions, i.e., microbial capture by NG and their killing ability due to activation of NADPH oxidases and normalization of microbicidal reserve capacity in the NG cell population. Positive clinical effect included reduction of clinical symptoms in acute period, absence of PID exacerbations over follow-up for 6 months (85.6% of cases). Occasional exacerbations of PID were associated with medical manipulations (5.7%) and unprotected sexual contacts (5.7%).&#x0D; The immunopathogenetically proven approach to correction of combined functional impairment of immune system in the women with PID shows a positive clinical and immunological effect.

Regulation of immune response against third-stage Gnathostoma spinigerum larvae by human genes.

Gnathostomiasis is an important zoonosis in tropical areas that is mainly caused by third-stage Gnathostoma spinigerum larvae (G. spinigerum L3). This study aimed to prove whether G. spinigerum L3 produces extracellular vesicles (EVs) and investigate human gene profiles related to the immune response against the larvae. We created an immune cell model using normal human peripheral blood mononuclear cells (PBMCs) co-cultured with the larvae for 1 and 3 days, respectively. The PBMCs were harvested for transcriptome sequencing analysis. The EV ultrastructure was examined in the larvae and the cultured medium. Extracellular vesicle-like particles were observed under the larval teguments and in the pellets in the medium. RNA-seq analysis revealed that 2,847 and 3,118 genes were significantly expressed on days 1 and 3 after culture, respectively. The downregulated genes on day 1 after culture were involved in pro-inflammatory cytokines, the complement system and apoptosis, whereas those on day 3 were involved in T cell-dependent B cell activation and wound healing. Significantly upregulated genes related to cell proliferation, activation and development, as well as cytotoxicity, were observed on day 1, and genes regulating T cell maturation, granulocyte function, nuclear factor-κB and toll-like receptor pathways were predominantly observed on day 3 after culture. G. spinigerum L3 produces EV-like particles and releases them into the excretory-secretory products. Overall, genotypic findings during our 3-day observation revealed that most significant gene expressions were related to T and B cell signalling, driving T helper 2 cells related to chronic infection, immune evasion of the larvae, and the pathogenesis of gnathostomiasis. Further in-depth studies are necessary to clarify gene functions in the pathogenesis and immune evasion mechanisms of the infective larvae.

Poly(2-ethyl-2-oxazoline)-Conjugated Hemoglobins as a Red Blood Cell Substitute.

Hemoglobin wrapped covalently with poly(2-ethyl-2-oxazoline)s (POx-Hb) is characterized physicochemically and physiologically as an artificial O2 carrier for use as a red blood cell (RBC) substitute. The POx-Hb is generated by linkage of porcine Hb surface-lysines to a sulfhydryl terminus of the POx derivative, with the average binding number of the polymers ascertained as 6. The POx-Hb shows moderately higher colloid osmotic activity and O2 affinity than the naked Hb. Human adult HbA conjugated with POx also possesses equivalent features and O2 binding properties. The POx-Hb solution exhibits good hemocompatibility, with no influence on the functions of platelets, granulocytes, and monocytes. Its circulation half-life in rats is 14 times longer than that of naked Hb. Hemorrhagic shock in rats is relieved sufficiently by infusion of the POx-Hb solution, as revealed by improvements of circulatory parameters. Serum biochemistry tests and histopathological observations indicate no acute toxicity or abnormality in the related organs. All results indicate that POx-Hb represents an attractive alternative for RBCs and a useful O2 therapeutic reagent in transfusion medicine.

Correlation between the Chemiluminescent Activity of Neutrophilic Granulocytes and the Lipid Peroxidation-Antioxidant Defense System in Gastric Cancer Associated with Helicobacter pylori Infection.

To study the processes of lipid peroxidation and the activity of antioxidant defense enzymes depending on the chemiluminescent activity of neutrophilic granulocytes in patients with gastric cancer associated with H. pylori infection, depending on the stage. A total of 39 patients with stage I-II gastric cancer and 30 patients with stage III-IV gastric cancer were examined. A study of the chemiluminescent activity of neutrophilic granulocytes was carried out and the parameters of the lipid peroxidation system and antioxidant protection in plasma were determined using the spectrophotometric method. Statistical data processing was performed using the Statistica 7.0 software package (StatSoft, St Tulsa, OK, USA). In patients with gastric cancer associated with H. pylori infection, regardless of stage, the proportion of neutrophilic granulocytes with normal activity did not exceed 1/3 of the total number of patients, and the remaining 2/3 of patients had altered chemiluminescent activity of neutrophilic granulocytes. In patients with gastric cancer, by I-II stage of the disease, the majority revealed a reduced function of neutrophilic granulocytes, and in patients with gastric cancer in stage III-IV of the disease, the majority showed increased chemiluminescent activity of neutrophilic granulocytes. In all patients with gastric cancer associated with H. pylori infection, regardless of the stage of the disease, an increase in lipid peroxidation processes with activation of antioxidant defense enzymes was detected. At the same time, there were no statistically significant differences between the indicators of the system lipid peroxidation-antioxidant protection depending on the stage of gastric cancer and the chemiluminescent activity of neutrophilic granulocytes, which likely indicates that all reactive oxygen species produced by neutrophilic granulocytes in the respiratory burst are consumed locally, minimally affecting the development of oxidative stress in the blood plasma.

Glycopeptide Antibiotics Impair Neutrophil Effector Functions

Introduction: Neutrophilic granulocytes represent the first line of defense against microorganisms. Granulocytes phagocytose microorganisms and specifically synthesize oxygen radicals against them, which eventually kills the invaders. Methods: Neutrophilic granulocytes were isolated from peripheral blood of healthy volunteer donors. Putative interference of new-generation antibiotics with neutrophil function was tested using a collection of granulocyte-stimulating agents and Amplex™ Red-based plate assay and flow cytometry-based respiratory burst assays. In addition, phagocytosis of E. coli, IL-8 production, bactericidal activity, and CD62L expression of granulocytes were evaluated. Results: Of note, we found that the two glycopeptide antibiotics dalbavancin and teicoplanin inhibited ROS production upon granulocyte activation via different signaling pathways in a dose-dependent manner. Dalbavancin also blocked the PMA-induced shedding of CD62L. In contrast, the oxazolidinone antibiotics tedizolid and linezolid had no effect on neutrophil function, while the combination of ceftazidime/avibactam dose dependently inhibited the fMLP/Cytochalasin B-induced granulocyte burst in a dose-dependent manner. Additionally, we showed that dalbavancin and teicoplanin as well as sulfametrole/trimethoprim and ceftazidime/avibactam inhibited baseline and PMA-induced IL-8 production by neutrophilic granulocytes. Moreover, dalbavancin impaired the bactericidal activity of neutrophilic granulocytes. Conclusion: We here identified hitherto unknown inhibitory effects of several classes of antibiotics on the effector functions of neutrophilic granulocytes.

Increased expression of tyrosine protein phosphatase (CD45) on the surface of human blood granulocytes under the influence of the plague microbe vaccine strain &lt;I&gt;Yersinia pestis&lt;/I&gt; EV NIIEG &lt;I&gt;ex vivo&lt;/I&gt; and &lt;I&gt;in vivo&lt;/I&gt;

Tyrosine protein phosphatase (common leukocyte antigen CD45) regulates FcᵧR-mediated cell signaling and secretory function of neutrophilic granulocytes (NG) when interacting with antigen-antibody immune complexes. The aim of the work is to study changes in the expression of CD45 on the surface of human granulocytes in ex vivo modeling of bacteremia by live cells of the plague microbe vaccine strain Yersinia pestis EV NIIEG and to evaluate the priming effect of the live plague vaccine (LPV) in vivo in terms of this parameter. The expression density of CD45 on NG was determined by flow cytometry in conventional units of fluorescence intensity (MFI) after staining the cells with the CD45-FITC labeled mouse antibody reagent (Backman Coulter, USA) during immunophenotyping of blood leukocytes according to the Lyse/No Wash protocol. In donors not previously vaccinated against plague (group 1), the value of the indicator was assessed before and 30 min, 2 h, 6 h after the addition of Y pestis EV cells to whole blood at a dose of 108 mc/ml, as well as 1 month and 6 months after the primary anti-plague vaccination. In individuals who had previously been repeatedly vaccinated with LPV in the territory of the natural plague focus (group 2), CD45 expression on blood granulocytes was determined one year after the last annual vaccination, and then 1 month and 6 months after revaccination. Getting into human blood, living cells of the vaccine strain Y pestis EV of the plague microbe induced a change in the NC phenotype already after 30 minutes, associated with a 3.5-fold increase in the surface expression of CD45, which remained at an elevated level for 6 hours. The studied indicator depended ex vivo on the degree of resistance of plague microbes to phagocytosis and killing of NG. Plague vaccination had a similar stimulating effect on human peripheral blood NG in vivo. Under the influence of HPV, CD45 expression increased on blood NG in groups 1 and 2 one month after vaccination, and the changes persisted in volunteers for 6 months. The experimental data obtained in the work may reflect the result of NG priming with lipopolysaccharide and other Y. pestis antigens. The registered functional activation of NG by expression of tyrosine protein phosphatase probably indicates the formation of “immune memory” at the level of innate immunity cells under the influence of LPV, the functioning of which explains the development of a faster and more intense antigen-specific immune response to repeated introduction of the plague vaccine into the body.

Live bacterial ligands universally regulate mTOR activity but are not essential for homeostatic innate immunity

Abstract Multiple studies have reported significant impact of gut microbiota on hematopoiesis, including granulocyte development and functional defects. Germ-Free (GF) mice show developmental defects due to lack of live bacteria; underscored by the development of Altered Schaedler Flora (ASF), a community of 8 bacterial species sufficient to rescue developmental immune and gastrointestinal defects. Mimicking gnotobiosis by using antibiotics perturbs the microbiome systemically. Therefore, results from such studies may represent sequelae of the drug perturbation rather than simply modifying microbiota. We studied the impact of gut microbiota signals on murine hematopoiesis without antibiotics or fecal transfer. Namely, by using mice (from Taconic) generated by embryonic transfer of C57/Bl6 fertilized eggs into females with controlled microbiota, totaling 4 groups of mice: 1. GF; 2. ASF (no Gammaproteobacteria); 3. Excluded Flora (EF, includes Gammaproteobacteria); 4. WildR 7(wild mouse microbiome). We found no significant differences in either number or effector function of bone-marrow neutrophil granulocytes, myeloid progenitors, or stem cells. The single-cell genomic landscape of CD117+ bone-marrow progenitors confirmed flow analyses but revealed a profound defect in gnotobiotic hematopoietic signatures. Importantly, standard pathogen free C57/BL6 mice were inappropriate controls. While gnotobiotic mice likely receive inert TLR stimulation via bedding and food, the addition of any group of live bacteria was sufficient to rescue gene expression downstream of mTOR signaling. Such robust signatures could be considered so essential to life that they do not depend on any single bacterial clade. This project is supported by NIH R01HL122661.

Immunomodulation of neutrophil granulocyte functions by bacterial polyphosphates.

Polyphosphates are highly conserved, linear polymers of monophosphates that reside in all living cells. Bacteria produce long chains containing hundreds to thousands of phosphate units, which can interfere with host defense to infection. Here, we report that intratracheal long-chain polyphosphate administration to C57BL/6J mice resulted in the release of proinflammatory cytokines and influx of Ly6G+ polymorphonuclear neutrophils in the bronchoalveolar lavage fluid causing a disruption of the physiologic endothelial-epithelial small airway barrier and histologic signs of lung injury. Polyphosphate-induced effects were attenuated after neutrophil depletion in mice. In isolated murine neutrophils, long-chain polyphosphates modulated cytokine release induced by lipopolysaccharides (LPS) from Gram-negative bacteria or lipoteichoic acid from Gram-positive bacteria. In addition, long-chain polyphosphates induced immune evasive effects in human neutrophils. In detail, long-chain polyphosphates downregulated CD11b and curtailed the phagocytosis of Escherichia coli particles by neutrophils. Polyphosphates modulated the migration capacity by inducing CD62L shedding resulting in CD62Llow and CD11blow neutrophils. The release of IL-8 induced by LPS was also significantly reduced. Pharmacologic blockade of PI3K with wortmannin antagonized long-chain polyphosphate-induced effects on LPS-induced IL-8 release. In conclusion, polyphosphates govern immunomodulation in murine and human neutrophils, suggesting polyphosphates as a therapeutic target for bacterial infections to restore innate immune defense.

Granulocyte development, tissue recruitment and function during allergic inflammation.

Granulocytes provide a fast innate response to pathogens and allergens. In allergy and anti-helminth immunity, epithelial cells of damaged barriers release alarmins like IL-25, IL-33 and TSLP but also chemokines like CXCL1 or CCL11 to promote cell recruitment and inflammation. In addition, mast cells positioned at barrier tissue sites also quickly release mediators upon specifically sensing antigens through IgE bound to FcεR1 on their surface. Released mediators induce the recruitment of different granulocytes in a timely ordered manner. First, neutrophils extravasate from the blood vasculature to the side of alarmin release and promote a potent inflammatory response. Alarmins and activated mast cells further promote activation of ILC2s and recruitment of basophils and eosinophils, which inhibit neutrophil recruitment and enhance tissue type 2 immunity. In addition to their potent pro-inflammatory effector functions, granulocytes can also contribute to termination and resolution of inflammation. Here, we summarize the development and tissue recruitment of granulocyte subsets, describe general effector functions and aspects of their increasingly appreciated role in limiting tissue damage. We further discuss targeting approaches for therapeutic interventions in allergic disorders. This article is protected by copyright. All rights reserved.