Neutrophils Induce the Maturation of Immature Dendritic Cells: A Regulatory Role of Neutrophils in Adaptive Immune Responses

Th1-type immune cytokines are essential to establish adaptive immunity against various microbial pathogens, including Escherichia coli, which cause most urinary tract infections (UTIs). Dendritic cells (DCs) are vital to initiate Th1 immunity, while neutrophils, also referred to here as polymorphonuclear leukocytes (PMN) are reported to be involved in Th1 immunity initiation by secreting several chemokines and cytokines. We found that lipopolysaccharide (LPS)-triggered PMN (LPS-PMN) in vitro induced strong up-regulation of DCs surface markers CD40, CD80, MHC-II (Ia^b), and CD86 either by secreting soluble factors, such as TNF-α, or by PMN-DC cellular contact. LPS-PMN also stimulated DCs to produce IL-12 and TNF-α. Furthermore, purified DCs activated by LPS-PMN were able to present specific antigen to T cells and drive Th1 differentiation by producing large amount of IFN-γ but low amount of IL-4. Our results suggest a regulatory role of PMN for DCs function in adaptive immune responses, thereby providing a link between innate and adaptive immunity.     

Neuropsychological Diagnosis of Decreased Consciousness after Severe Craniocerebral Trauma in Children

Neuroscience and Behavioral Physiology - Objectives. To identify the features of the recovery of consciousness and higher mental function in children aged 6–17 years during the first four...     

Lysosomal Enzyme Release from Human Neutrophils Adherent to Foreign Material Surfaces: Enhanced Release of Elastase Activity

Neutrophils are the major phagocytic white blood cell present during the acute inflammatory response to cardiovascular medical devices and can become activated to release a wide variety of products that help mediate the overall host response. The purpose of this investigation was to develop an in vitro system to study the release of lysosomal enzymes from neutrophils adherent to biomaterial surfaces. Neutrophils isolated from peripheral human blood were allowed to adhere to different biomaterials and lysosomal enzyme release assessed by monitoring elastase-like activity in the supernatant. The number of adherent neutrophils with intact cytoplasmic membranes was estimated by extracting the cells and quantifying lactate dehydrogenase. Stimulated and non-stimulated neutrophils released significantly different amounts of elastase-like activity depending on the biomaterial surface to which they were adhered. The techniques developed in this study form the basis of an in vitro system for investigating the events associated with neutrophil/biomaterial interactions as well as a method for evaluating the white blood cell response to the materials used in circulatory support devices.     

The Role of a Chymotrypsin-like Enzyme in Histamine Release from Rat Mast Cells

The presence of a chymotrypsin-like enzyme in rat mast cells has been confirmed, and it has been shown that intact mast cells contain the fully activated enzyme without losing their histamine content. It has been shown by means of inhibitors that the chymotrypsin-like enzyme is distinct from the heat-labile SH enzyme required for the histamine releasing action of compound 48/80. The synthetic ester used as a substrate for chymotrypsin released histamine from rat mast cells probably by a non-enzymic reaction.     

Preeclampsia Status Controls Interleukin-6 and Soluble IL-6 Receptor Release from Neutrophils and Endothelial Cells: Relevance to Increased Inflammatory Responses

Increased neutrophil–endothelial binding and inflammatory responses are significant pathophysiological events in the maternal vascular system in preeclampsia, a hypertensive disorder in human pregnancy. Interleukin 6 (IL-6) and its soluble receptors (soluble IL-6R (sIL-6R) and soluble gp130 (sgp130)) are critical inflammatory mediators. During pregnancy, maternal IL-6 and sgp130 levels were increased, but sIL-6R levels were decreased, in women with preeclampsia compared to normotensive pregnant women. However, little is known about differences in IL-6, sIL-6R, and sgp130 production by neutrophils and endothelial cells between normal pregnancy and preeclampsia. To study this, we isolated neutrophils and cultured human umbilical vein endothelial cells (HUVECs) from normal and preeclamptic pregnancies. Production of IL-6, sIL-6R, and sgp130 was measured. The role of placental factor(s)-mediated neutrophil production of IL-6, sIL-6R, and sgp130 was also determined by pretreating neutrophils with placental conditioned medium generated from placental villous cultures. We found that IL-6 and sgp130 were mainly produced by endothelial cells, while sIL-6R was mainly produced by neutrophils. Endothelial cells from preeclampsia produced significantly more IL-6 and sgp130, and neutrophils from preeclampsia produced significantly less sIL-6R than normal pregnancy cells. Interestingly, production of IL-6, sIL-6R, and sgp130 were time-dependently increased when neutrophils and endothelial cells were co-cultured. We also found that neutrophils from normal pregnancies produced more IL-6, but less sIL-6R, after being primed by preeclamptic-placental conditioned medium. These results demonstrated that neutrophils and endothelial cells have different capacities in producing IL-6, sIL-6R, and sgp130 between normal pregnancy and preeclampsia. These results also provide evidence that the placenta plays a role in inducing neutrophil activation in preeclampsia.     

Rapid Adhesive Responses of Endothelial Cells and of Neutrophils Induced by Leukotriene B4 are Mediated by Leucocytic Adhesion Protein CD18

Controversy has existed as to the ability of leukotriene B4 (LTB4) to enhance adhesive properties of human neutrophils (PMN) and endothelial cells. We found that LTB4 induced a rapid but transient adhesion of PMN to an albumin-coated plastic surface and to cultured human umbilical vein endothelial cells (HUVEC). Although the adhesive response of PMN to the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (fMLP) was longer lasting, peak hyperadherence was of similar magnitude as to LTB4 and was less susceptible to assay conditions. Adherence induced by either LTB4 or fMLP could be abrogated by the monoclonal antibody 60.3, indicating similar dependence on the leucocyte adhesion protein CD18. Lipoxin A did not induce PMN hyperadherence. Treating HUVEC with LTB4, but not with its omega-oxidized metabolites 20-OH- and 20-COOH-LTB4, lipoxin A, or with fMLP conferred a rapid, dose-related, enhanced adhesion of PMN. This effect was dependent on CD18 and on divalent cations. It disappeared with prolonged exposure to LTB4, required a metabolically active HUVEC, and was not due to passive binding of LTB4 to HUVEC. Thus, LTB4 induces a transient expression of hyperadhesiveness in HUVEC as well as in neutrophils, and both effects are dependent on expression of CD18.     

白三烯C4在哮喘发病中的作用

目的探讨白三烯c4在哮喘发病中的作用。方法采用ELISA法，分别测定56例支气管哮喘发作期，60例缓解期以及60例正常对照组血清中LTC4水平。结果哮喘发作组和哮喘缓解组LTC4（14．63±2．85）ng／mL和（13．92±2．46）ng／mL水平显著高于正常对照组（2．42±0．36）ng／mL。而哮喘患者急性发作组和缓解组之间比较差异无统计学意义。结论LTC4是哮喘发生发展的重要炎性因子。     

牛磺酸对大鼠面神经损伤的疗效观察

目的：探讨牛磺酸对大鼠面神经损伤的治疗作用。方法：制备大鼠面神经损伤的动物模型并将其随机分为两组。牛磺酸组：10％牛磺酸1ml/100mg灌胃，分别于损伤后第14天、28天，检测伤后面神经复合动作电位传导速率、幅度和潜伏期；对照组：用等量的生理盐水灌胃。结果：牛磺酸组动作电位传导速度与对照组相比，有显差异性（P＜0．01）。结论：牛磺酸可促进面神经损伤的恢复。     

Hydrogen Peroxide Release by Rat Alveolar Macrophages: Comparison with Blood Neutrophils

Hydrogen peroxide release was examined using biochemical and cytochemical techniques in rat alveolar macrophages, at rest and during phagocytosis, and compared with rat blood neutrophils. Using biochemical techniques, alveolar macrophages released small amounts of hydrogen peroxide at rest, and no increase was observed after challenge with opsonized and nonopsonized zymosan particles at several particle-cell ratios (1:1 to 1:1,000). Neutrophils released similar quantities of hydrogen peroxide at rest but showed a 12-fold increase in hydrogen peroxide release following exposure to opsonized zymosan particles. Using cytochemical techniques to localize sites of hydrogen peroxide release, resting neutrophils showed little deposition of reaction product at the cell surface and occasional deposits in endocytotic vesicles. After exposure to latex particles, a dense reaction product was observed between the particle and the cell membrane, indicating significant increases in hydrogen peroxide release at the sites of particle contact with the neutrophil. The resting macrophage displayed a light, uniform precipitation of cerium over the cell surface and lining intracellular channels and endocytotic vesicles and vacuoles. Following particle exposure, there was no significant difference in the density or distribution of reaction product. These findings, together with previous studies of oxidative metabolism, suggest that alveolar macrophages do not release increased quantities of hydrogen peroxide during phagocytosis. In contrast to neutrophils, oxidative-dependent metabolic pathways may not be of primary importance for microbial killing by alveolar macrophages.     

Severe Cytokine Release Syndrome after Haploidentical Peripheral Blood Stem Cell Transplantation

Inflammatory cytokines released by activated lymphocytes and innate cells in the context of cellular therapy can cause fever, vasodilatation, and end-organ damage, collectively known as cytokine release syndrome (CRS). CRS can occur after allogeneic blood or marrow transplantation, but is especially prevalent after HLA-haploidentical (haplo) peripheral blood transplantation (PBT). We reviewed charts of all patients who underwent haplo-PBT between October 1, 2013, and September 1, 2017 and graded CRS in these patients. A total of 146 consecutive patients who underwent related haplo-PBT were analyzed. CRS occurred in 130 patients (89%), with most cases of mild severity (grade 0 to 2). Severe CRS (grade 3 to 5) occurred in 25 patients (17%). In this group with severe CRS, 13 patients had encephalopathy, 12 required hemodialysis, and 11 were intubated. Death from the immediate complications of CRS occurred in 6 patients (24% of the severe CRS group and 4% of the entire haplo-PBT cohort). The cumulative probability of nonrelapse mortality (NRM) was 38% at 6 months for the patients with severe CRS and 8% (121 of 146) in patients without severe CRS. In conclusion, CRS occurs in nearly 90% of haplo-PBTs. Older haplo-PBT recipients (odds ratio [OR], 2.4; 95% confidence interval [CI], .83 to 6.75; P = .11) and those with a history of radiation therapy (OR, 3.85; 95% CI, 1.32 to 11.24; P = .01) are at increased risk of developing severe CRS. Although most recipients of haplo-PBT develop CRS, <20% experience severe complications. The development of severe CRS is associated with a significantly increased risk of NRM.     

Trauma and Adaptation in Severe Mental Illness: The Role of Self-Reported Abuse and Exposure to Community Violence

ABSTRACT

The authors examined the role of self-reported physical and/or sexual abuse and recent exposure to community violence on three adaptation outcomes in Severe Mental Illness (SMI): psychotic symptoms, demoralization, and substance abuse. One hundred and nine (109) individuals with SMI were administered an extensive protocol that included the pertinent variables. Structural Equation Modeling analyses indicated that abuse predicted psychotic symptoms and demoralization, whereas exposure to community violence predicted substance abuse. These findings point to different possible trauma-adaptation configurations, and suggest that both past and present trauma complicates the adaptation of people with SMI.     

Detection of Lactoferrin and Myeloperoxidase Release from Single Neutrophils by a Protein A Plaque Assay

A haemolytic plaque assay was adopted to detect release of lactoferrin and myeloperoxidase (MPO) from single neutrophils. Target erythrocytes coated with protein A were bound as a monolayer by poly-L-lysine to the surface of a plastic dish. Secreted lactoferrin and MPO induced plaque formation dependent on the reaction with complement and specific antiserum producing lysis of the protein-A-coated sheep red blood cells. Lactoferrin was found to be released spontaneously from a fraction of neutrophils while MPO was released only after phagocytosis, reflecting different mechanisms for degranulation of MPO-containing azurophil and lactoferrin-containing specific granules.     

The Dual Role of Neutrophils in HIV Infection

Purpose of Review

We summarize what is known about neutrophils in HIV infection, focusing on their potential roles in HIV protection, acquisition, and pathogenesis.

Recent Findings

Recent studies have demonstrated that neutrophil-associated proteins and cytokines in genital tissue pre-infection associate with HIV acquisition. However, recent in vivo assessment of highly exposed seronegative individuals and in vitro studies of anti-HIV functions of neutrophils add to older literature evidence that neutrophils may be important in a protective response to HIV infection.

Summary

Neutrophils are important for containment of pathogens but can also contribute to tissue damage due to their release of reactive oxygen species, proteases, and other potentially harmful effector molecules. Overall, there is a clear evidence for both helpful and harmful roles of neutrophils in HIV acquisition and pathogenesis. Further study, particularly of tissue neutrophils, is needed to elucidate the kinetics, phenotype, and functionality of neutrophils in HIV infection to better understand this dichotomy.

     

Montelukast Inhibits Leukotriene Stimulation of Human Dendritic Cells in vitro

Background: Leukotrienes are potent inflammatory mediators which modulate immune responses and induce bronchoconstriction in susceptible individuals. Montelukast (MK) is a leukotriene receptor (CysLT1) antagonist that has been shown to prevent exacerbation of asthma. Considering the plethora of potential cellular targets for MK, specific mechanisms for its therapeutic action are still not fully understood. In vitro, we determined whether human dendritic cell function could be affected by leukotriene C(4) (LTC(4)) treatment and whether MK had potential in modulating this response. We also studied the effect of LTC(4) in the context of response to an airway virus (respiratory syncytial virus, RSV). Methods: Human monocyte-derived dendritic cells (moDCs) exposed to LTC(4), MK, or both, were cocultured with autologous T cells, with or without RSV. The effects of LTC(4) and MK on cell function were determined by ELISA and proliferation assays. Results: Both moDCs and their precursors - monocytes - express LTC(4) receptor CysLT1, making them potential targets for MK. moDCs cultured with LTC(4) release the eosinophil chemoattractant RANTES (CCL5) and induce greater T cell proliferation. Both were blocked by the presence of MK. MK treatment, albeit anti-inflammatory, did not interfere with the moDC-dependent T cell-proliferative responses induced by RSV. Conclusions: LTC(4), chronically present in the airways of asthma patients, could induce an exaggerated inflammatory response to airway infection via dendritic cell activation, which would be prevented by MK. Our study provides additional insight into the mechanisms of action of this leukotriene receptor antagonist.     

Interferon-Gamma Stimulates Neopterin Release from Cultured Kidney Epithelial Cells

The ability of cultured kidney epithelial cells (KEC) to secrete neopterin, which is a marker of the activation of immune system was studied. In this study inlerferon gamma (IFN-γ) was shown to induce neopterin release from KEC in a dose- and time-dependent manner. Many other cytokines and mitogens (IL-1β, IL-2, IL-6, LPS and phorbol ester) were tested for their ability to induce neopterin in KEC but all failed to induce a significant release of neopterin from KEC. By itself TNF- á induced a release of small amounts of neopterin but strongly potentiated the effect of IFN-γ in a synergistic manner to induce neopterin secretion. These data indicate that not only monocytes and macrophages which it is well known secrete neopterin, but KEC are responsible also for the high serum or urine level of neopterin observed in patients with kidney allograft rejection or infections episodes. As the amount of neopterin released by KEC is smaller than that secreted by activated macrophages, the contribution of KEC to the overall production of neopterin during certain diseases may be small.     

Release of Mediators from Purified Rat Mast Cells during Phagocytosis

Purified mature rat peritoneal mast cells, on exposure to zymosan or latex beads, phagocytize these particles, although less efficiently than macrophages. During phagocytosis, histamine, beta-glucuronidase, and eosinophil chemotactic factor are released from mast cells in a time-, temperature- and dose-dependent fashion. Complement components, cytochalasin B (5 microgram/ml), and indomethacin (10-6M), enhanced mediator release, whereas compound BW 755C (20 microgram/ml), a cyclooxygenase and lipoxygenase inhibitor of arachidonate metabolism, totally abolished this process. Phagocytosis of mast cell thus activates intracellular mechanisms that closely resemble those observed with other phagocytic cells. These observations add a new perspective to the role of mast cells in inflammatory events.     

A Novel Molecular Complex Expressed on Immature B Cells: A Possible Role in T Cell-Independent B Cell Development

To identify surface molecules that may play a role in regulating ileal Peyer''s patch (PP) B cell growth, we generated monoclonal antibodies (mAbs) and then selected them for a unique reactivity with ileal PP B cells. Flow cytometric analysis identified a mAb (SIC4.8R) that labeled 97% of ileal and 50–60% of jejunal PP sIgM⁺B cells. SIC4.8R also labeled a subpopulation of cortical thymocytes but few B or T cells in other lymphoid tissues, including bone marrow. Immunohistochemistry revealed intense SIC4.8R staining of B cells in the cortex of ileal PP follicles. SIC4.8R also labeled bovine PP B cells, a murine pro-B cell line, and pre-B cells in human bone marrow. Protein chemistry revealed that a structurally similar molecular complex was expressed on sheep ileal PP B cells and thymocytes and murine pro-B cells. Addition of soluble SIC4.8R to cultured ileal PP B cells reduced apoptotic cell death, elevated proliferative responses, partially inhibited anti-Ig-induced cell death, and induced IL-4 responsiveness. In contrast, soluble SIC4.8R had an antiproliferative effect on a mouse pro-B cell line. Finally, SIC4.8R labeling declined following the stimulation of ileal PP B cells with CD40 ligand. In conclusion, the present investigation determined that SIC4.8R identified a novel molecular complex that is expressed at several stages of T cell-independent B cell development in a variety of mammalian species. This observation confirmed that PP B cells are developmentally distinct from other B cell populations in sheep and suggested that the bone marrow may not be a site of B lymphopoiesis in young lambs.     

Decreased Density in Membrane Localized Macromolecules in Cells Enlarged after X-Irradiation or Polyploidization

Cytophotometric measurements of DNA, dry mass (total proteins) and surface localized IgM and la were performed on individual cells of a Burkitt lymphoma derived cell line after Xirradiation and after polyploidization. Blockage of cell division was achieved with 250 r, and an arrest in G2 was found 48 hr after irradiation. The cells unable to divide increased in volume and total protein content. Cell enlargement was also achieved by polyploidization. The amount of surface localized IgM and la did not keep up pace with the increase in total proteins, thus their density decreased. This was reflected in decreased sensitivity of the enlarged cells to the cytotoxic effect of specific antisera.