cytochalasin-b and Inflammation

Various cationic polyelectrolytes (poly-alpha-amino acids and histones), lectins, the chemotactic peptide, f-methionyl-leucyl-phenylalanine (fMLP), the calcium ionophore A23187, and phorbol myristate acetate (PMA) were investigated regarding their capacity to induce luminol-dependent chemiluminescence (LDCL) and superoxide production by human blood leukocytes. Although when tested individually, poly-L-arginine (PARG), phytohemagglutinin (PHA), concanavalin A (Con A), or fMLP induced only a low to moderate LDCL response, very intense synergistic CL reactions were obtained by mixtures of PARG + PHA, PARG + Con A, PARG + PHA + fMLP, Ca2 + ionophore + PARG + PHA + fMLP, and PARG + PMA. The sequence of addition of the various agents to WBC in the presence of luminol absolutely determined the intensity of the LDCL signals obtained, the highest reactions being achieved when the WBC were preincubated for 2-3 min with A23187 followed by the sequential addition of fMLP, PARG, and PHA. These "multiple hits" induced CL reactions which were many times higher than those obtained by each factor alone. On the other hand, neither poly-L-lysine, poly-L-ornithine, poly-L-histidine, nor poly-L-asparagine, when employed at equimolar concentrations, cooperated efficiently with PHA and fMLP to trigger synergistic LDCL responses in leukocytes. Concomitantly with the induction of LDCL, certain ligand mixtures also triggered the production of superoxide. The LDCL which was induced by the "cocktail" of agents was markedly inhibited by sodium azide (93% inhibition), but to a lesser extent by catalase (10% inhibition) or by superoxide dismutase (20%-60% inhibition). On the other hand, scavengers of singlet oxygen and OH (sodium benzoate, histidine) did not affect the synergistic LDCL responses induced by these multiple ligands. Cytochalasin B also markedly inhibited the LDCL responses induced either by soluble stimuli or by streptococci preopsonized either with histone or with polyanethole sulfonate. The LDCL responses which were induced by mixtures of PARG and concanavalin A were also strongly inhibited by mannose, alpha-methyl mannoside, and poly-L-glutamic acid. The data suggest that the LDCL responses induced by the soluble ligands involved a myeloperoxidase-catalyzed reaction. The possible employment of "cocktails" of ligands to enhance the bactericidal effects of PMNs, macrophages, and natural killer cells on microbial cells and mammalian targets is discussed.

Topics: Antimetabolites; Calcimycin; Carbohydrates; Cytochalasin B; Drug Synergism; Electrolytes; Histones; Humans; Inflammation; Lectins; Leukocytes; Ligands; Luminescent Measurements; Luminol; Lysophosphatidylcholines; N-Formylmethionine Leucyl-Phenylalanine; Peptides; Polymyxin B; Superoxides; Tetradecanoylphorbol Acetate

Topics: Antigen-Antibody Complex; Calcium; Cell Membrane; Concanavalin A; Cyclic AMP; Cytochalasin B; Humans; Hydrogen Peroxide; Inflammation; Lysosomes; Magnesium; Membrane Potentials; N-Formylmethionine; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Oligopeptides; Opsonin Proteins; Oxidation-Reduction; Phagocytosis; Potassium; Sodium; Superoxides

Extracellular vesicles (EVs) secreted from probiotics, defined as live microorganisms with beneficial effects on the host, are expected to be new nanomaterials for EV-based therapy. To clarify the usability of probiotic-derived EVs in terms of EV-based therapy, we systematically evaluated their characteristics, including the yield, physicochemical properties, the cellular uptake mechanism, and biological functions, using three different types of probiotics:

Topics: Adjuvants, Immunologic; Animals; beta-Cyclodextrins; Cells, Cultured; Chlorpromazine; Cytochalasin B; Cytokines; Endocytosis; Extracellular Vesicles; Immunity, Innate; Immunologic Factors; Immunotherapy; Inflammation; Mice; Probiotics; RAW 264.7 Cells

Three new coumarin derivatives, 8-formylalloxanthoxyletin (1), avicennone (2), and (Z)-avicennone (3), have been isolated from the stem bark of Zanthoxylum avicennae (Z. avicennae), together with 15 known compounds (4-18). The structures of these new compounds were determined through spectroscopic and MS analyses. Compounds 1, 4, 9, 12, and 15 exhibited inhibition (half maximal inhibitory concentration (IC₅₀) values ≤7.65 µg/mL) of superoxide anion generation by human neutrophils in response to formyl-l-methionyl-l-leucyl-l-phenylalanine/cytochalasin B (fMLP/CB). Compounds 1, 2, 4, 8 and 9 inhibited fMLP/CB-induced elastase release with IC₅₀ values ≤8.17 µg/mL. This investigation reveals bioactive isolates (especially 1, 2, 4, 8, 9, 12 and 15) could be further developed as potential candidates for the treatment or prevention of various inflammatory diseases.

Topics: Adult; Coumarins; Cytochalasin B; Humans; Inflammation; Magnetic Resonance Spectroscopy; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Plant Bark; Plant Stems; Superoxides; Young Adult; Zanthoxylum

Glaucumolides A (1) and B (2), novel biscembranes composed of an unprecedented α,β-unsaturated ε-lactone, along with the known metabolites ximaolide A (3) and isosarcophytonolide D (4), were isolated from the cultured soft coral Sarcophyton glaucum. The structures of the new metabolites were determined by extensive spectroscopic analyses. Compounds 1 and 2 were shown to exhibit cytotoxicity against a limited panel of cancer cell lines. In anti-inflammation assay, compounds 1 and 2 displayed strong inhibition of superoxide anion generation and elastase release in human neutrophils stimulated by fMLP/CB. Furthermore, both 1 and 2 were shown to significantly inhibit the accumulation of the pro-inflammatory inducible nitric oxide synthase protein, and compounds 1-3 were found to effectively reduce the expression of cyclooxygenase-2 protein, in lipopolysaccharide-stimulated RAW264.7 macrophage cells.

Topics: Animals; Anthozoa; Anti-Inflammatory Agents; Antineoplastic Agents; Cell Line, Tumor; Cyclooxygenase 2; Cytochalasin B; Diterpenes; Drug Screening Assays, Antitumor; HL-60 Cells; Humans; Inflammation; Lactones; Leukemia, Promyelocytic, Acute; Lipopolysaccharides; Macrophages; Mice; Neutrophils; Nitric Oxide Synthase Type II; Precursor T-Cell Lymphoblastic Leukemia-Lymphoma; Superoxides

New four eunicellin-based diterpenoids, krempfielins J-M (1-4) were isolated from the organic extract of a Taiwanese soft coral Cladiella krempfi. The structures of the new metabolites were elucidated on the basis of extensive spectroscopic analysis. The structure of compound 2 is rare due to the presence of the highly oxygenated pattern. Anti-inflammatory activity of 1-6 to inhibit the superoxide anion generation and elastase release in FMLP/CB-induced human neutrophils was also evaluated, and 2 and 4 were shown to possess the ability to inhibit the elastase release.

Topics: Animals; Anthozoa; Anti-Inflammatory Agents; Cytochalasin B; Diterpenes; Dose-Response Relationship, Drug; Humans; Inflammation; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Pancreatic Elastase; Spectrum Analysis; Superoxides

This protocol describes microsphere-based protease assays for use in flow cytometry and high-throughput screening. This platform measures a loss of fluorescence from the surface of a microsphere due to the cleavage of an attached fluorescent protease substrate by a suitable protease enzyme. The assay format can be adapted to any site or protein-specific protease of interest and results can be measured in both real time and as endpoint fluorescence assays on a flow cytometer. Endpoint assays are easily adapted to microplate format for flow cytometry high-throughput analysis and inhibitor screening.

Topics: Animals; Biotinylation; Flow Cytometry; Fluorescence Resonance Energy Transfer; Green Fluorescent Proteins; High-Throughput Screening Assays; Humans; Inflammation; Kinetics; Microspheres; Peptide Hydrolases; Peptides; Reproducibility of Results; Temperature

Although the role of the actin cytoskeleton has become increasingly elucidated, the role of actin polymerization in inflammatory processes remains poorly understood. Here, we examine the role of the actin cytoskeleton during LPS-mediated inflammatory events in RAW264.7 cells and peritoneal macrophages. We observed that actin cytoskeleton disruption by cytochalasin B and siRNA to cytoplasmic actin strongly down-regulated LPS-mediated inflammatory responses such as NO production, PGE(2) release, and TNF-alpha secretion. Actin cytoskeleton disruption by cytochalasin B down-regulated a series of signaling cascades including PI3K, Akt, and IKK, but not MAPKs, necessary for NF-kappaB activation without down-regulating total forms of the proteins as assessed by measuring their phosphorylation levels. In particular, cytochalasin B significantly inhibited LPS-induced both phosphorylation and kinase activity of Src without altering total level, implying that Src may be a potential pharmacological target of actin cytoskeleton rearrangement. Moreover, the direct association of Src with actin was actin polymerization-dependent according to immunoprecipitation analysis performed with a GFP-actin wild type and HA-tagged Src. Therefore, our data suggest that actin cytoskeleton rearrangement may be a key event during the regulation of inflammatory responses that modulates the activity of Src and its downstream signaling molecules.

Topics: Actins; Animals; Cell Line; Cells, Cultured; Cytochalasin B; Humans; Inflammation; Inflammation Mediators; Male; Mice; Mice, Inbred C57BL; Polymers; src-Family Kinases

Neutrophil (PMN) contribution to the acute inflammatory processes may lead to an excessive generation of reactive oxygen metabolites species (ROS) and secretion of granule enzymes. We compared the effects of either phorbol myristate acetate (PMA) or N-formyl-methionyl-leucyl-phenylalanine (fMLP) in combination with a pre-treatment by cytochalasin B (CB) on the production of ROS and the release of total and active myeloperoxidase (MPO) by isolated equine PMNs. The ROS production was assessed by lucigenin dependent chemiluminescence (CL) and ethylene release by alpha-keto-gamma-methylthiobutyric acid (KMB) oxidation. In the supernatant of activated PMNs, total equine MPO was measured by ELISA and active MPO by the SIEFED (Specific Immunologic Extraction Followed by Enzymatic Detection) technique that allows for the study of the interaction of a compound directly with the enzyme. The stimulation of PMNs with CB-fMLP only modestly increased the release of MPO, but more than 70% of released MPO was active. PMA stimulation markedly increased the production of ROS and release of MPO, but more than 95% of released MPO was inactive. When PMNs were pre-incubated with superoxide dismutase (SOD) prior to PMA activation, the lucigenin enhanced CL, which is linked to the superoxide anion (O2-) production, was much more decreased than KMB oxidation, linked to the hydroxyl-like radical production. The addition of SOD prior to the activation of PMNs by PMA also limited the loss of the activity of released MPO. These results confirm the key role of O2- generation in the ROS cascade in PMN and reveal its critical role on MPO inactivation.

Topics: Animals; Biphenyl Compounds; Cell Degranulation; Cytochalasin B; Ethylenes; Horse Diseases; Horses; In Vitro Techniques; Inflammation; Luminescent Measurements; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Onium Compounds; Peroxidase; Reactive Oxygen Species; Superoxide Dismutase; Tetradecanoylphorbol Acetate

Bcr and Abr are GTPase-activating proteins for the small GTPase Rac. Both proteins are expressed in cells of the innate immune system, including neutrophils and macrophages. The function of Bcr has been linked to the negative regulation of neutrophil reactive oxygen species (ROS) production, but the function of Abr in the innate immune system was unknown. Here, we report that mice lacking both proteins are severely affected in two models of experimental endotoxemia, including exposure to Escherichia coli lipopolysaccharide and polymicrobial sepsis, with extensive microvascular leakage, resulting in severe pulmonary edema and hemorrhage. Additionally, in vivo-activated neutrophils of abr and bcr null mutant mice produced excessive tissue-damaging myeloperoxidase (MPO), elastase, and ROS. Moreover, the secretion of the tissue metalloproteinase MMP9 by monocytes and ROS by elicited macrophages was abnormally high. In comparison, ROS production from bone marrow monocytes was not significantly different from that of controls, and the exocytosis of neutrophil secondary and tertiary granule products, including lactoferrin, was normal. These data show that Abr and Bcr normally curb very specific functions of mature tissue innate immune cells, and that each protein has distinct as well as partly overlapping functions in the downregulation of inflammatory processes.

Topics: Animals; Cytochalasin B; Endotoxemia; Enzyme Activation; Escherichia coli; GTPase-Activating Proteins; Inflammation; Lipopolysaccharides; Lung Injury; Mice; Models, Biological; Mutation; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Phagocytosis; Proteins; Proto-Oncogene Proteins c-bcr; rac GTP-Binding Proteins; Reactive Oxygen Species

Experimental and clinical investigations using hyperosmotic solutions for resuscitation of hemorrhagic shock demonstrated modulation of the inflammatory response. Decreased postinjury hyperinflammation has been attributed to a reduction in neutrophil-mediated tissue damage. This study shows that cytoskeletal disruption with cytochalasinB did not reverse or prevent the inhibitory effect of an osmolarity increase on the neutrophil cytotoxic response to a formyl peptide. In cytochalasin-primed neutrophils, the hyperosmolarity-dependent inhibition promptly reversed after returning to iso-osmotic levels. Paradoxically, an increase in osmolarity after stimulation produced an increase in the release of reactive oxygen species to the extracellular medium. The inhibitory effect of hyperosmotic NaCl can be reproduced by solutions of similar osmolarity containing N-methyl glucamine or sucrose, but solutions containing mannitol allowed an almost complete response to N-formyl methionyl leucyl phenylalanine. The effects on the release of reactive oxygen species to the extracellular media found with the OxyBURST-bovine serum albumin assay correlated with the changes of the intracellular calcium signal, indicating that the inhibition by hyperosmolarity occurs near the receptor level.

Topics: Calcium; Chemotactic Factors; Cytochalasin B; Cytoskeleton; Humans; Inflammation; Models, Biological; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Osmolar Concentration; Osmosis; Reactive Oxygen Species; Signal Transduction; Sodium Chloride; Superoxides

To study different activation states in polymorphonuclear leukocytes (PMN) in mice, we compared the function of murine PMN obtained from the bone marrow (BMPMN) with those of PMN obtained by intraperitoneal induction with thioglycolate (TGPMN) or uric acid (UAPMN). When stimulated with chemotactic peptides, e.g., formyl-methionyl-leucyl-phenylalanine (fMLF), WKYMVM, or WKYMVm, the TGPMN and UAPMN showed greatly enhanced generation of reactive oxygen species (ROS) compared with BMPMN, which suggests that exudation to the peritoneum per se induces a primed state in the cells. The WKYMVm peptide was the most potent stimulant of ROS generation, and it desensitized for subsequent stimulation with fMLF or WKYMVM. This desensitization was broken by the addition of cytochalasin B. The TGPMN and UAPMN appeared to be fully primed, since no increase in response was induced by pretreatment with tumor necrosis factor alpha (TNF-alpha). In contrast, the BMPMN response was increased 2.5- to 3-fold. The differences in oxidative responses were supported by degranulation studies. Preincubation with TNF-alpha promoted CR3 expression on BMPMN, and this level of expression was also enhanced by WKYMVm. In contrast, CR3 expression on untreated TGPMN and UAPMN was already similar to that on TNF-alpha-primed BMPMN and could be only slightly enhanced by TNF-alpha treatment. Taken together, these results indicate that BMPMN are in a resting state and have the capacity to become primed, while peritoneal exudate PMN are already fully primed upon isolation. These results have major implications for murine neutrophil research and show the importance of defining which PMN subsets to use when investigating murine models.

Topics: Animals; Ascitic Fluid; Bone Marrow Cells; Cell Adhesion; Cytochalasin B; Exudates and Transudates; Female; Glass; Inflammation; Lymphocyte Activation; Macrophage-1 Antigen; Mice; Mice, Inbred C57BL; NADP; Neutrophils; Oligopeptides; Up-Regulation

In this study, we investigated whether luteolin monoglucuronide was converted to free aglycone during inflammation using human neutrophils stimulated with ionomycin/cytochalasin B and rats treated with lipopolysaccharide (LPS). beta-Glucuronidase activity was assayed using 4-methylumbelliferyl-glucuronide and methanol extracts of rat plasma containing luteolin monoglucuronide. The released 4-methylumbelliferone, a fluorescent molecule, was quantified by fluorometry. Deglucuronidation of luteolin monoglucuronide was examined by high-performance liquid chromatography (HPLC) analysis. HPLC analyses showed that the supernatants obtained from neutrophils stimulated with ionomycin/cytochalasin B hydrolyzed luteolin monoglucuronide to free luteolin. beta-Glucuronidase activity in human serum from patients on hemodialysis increased significantly compared with that from healthy volunteers. The beta-glucuronidase activity in rat plasma increased after i.v. injection of LPS. The ratio of luteolin to luteolin monoglucuronide in plasma of LPS-treated rats also increased. These results suggest that during inflammation beta-glucuronidase is released from stimulated neutrophils or certain injured cells and then deglucuronidation of flavonoids occurs.

Topics: Animals; Chromatography, High Pressure Liquid; Cytochalasin B; Expectorants; Flavonoids; Glucuronidase; Glucuronides; Humans; In Vitro Techniques; Inflammation; Ionomycin; Ionophores; Lipopolysaccharides; Luteolin; Neutrophils; Rats; Rats, Sprague-Dawley

L-selectin (leukocyte adhesion molecule 1/MEL-14), a member of the selectin family of cell adhesion molecules, mediates leukocyte rolling and leukocyte adhesion to endothelium at sites of inflammation. In addition, L-selectin mediates the binding of lymphocytes to high endothelial venules (HEV) of peripheral lymph nodes. The strong amino acid sequence conservation of the cytoplasmic domain of L-selectin between humans and mice suggests an important role for this region. Deletion of the COOH-terminal 11 amino acids from the approximately 17 amino acid cytoplasmic domain of L-selectin eliminated binding of lymphocytes to HEV in the in vitro frozen section assay, and also abolished leukocyte rolling in vivo in exteriorized rat mesenteric venules, but did not alter the lectin activity of L-selectin. Pretreatment of cells with cytochalasin B, which disrupts actin microfilaments, also abolished adhesion without affecting carbohydrate recognition. Therefore, the cytoplasmic domain of L-selectin regulates leukocyte adhesion to endothelium independent of ligand recognition, by controlling cytoskeletal interactions and/or receptor avidity.

Topics: Actin Cytoskeleton; Amino Acid Sequence; Animals; Base Sequence; Cell Adhesion; Cell Adhesion Molecules; Cell Line; Cell Movement; Cytochalasin B; Cytoplasm; DNA; Endothelium, Vascular; Flow Cytometry; Inflammation; L-Selectin; Leukocytes; Lymphatic System; Mice; Molecular Sequence Data; Precipitin Tests

Topics: Actins; Chemotaxis, Leukocyte; Colostrum; Cytochalasin B; Cytoskeleton; Depression, Chemical; Female; Humans; Inflammation; Neutrophils

Blood was drawn from healthy human volunteers and neutrophils and eosinophils were purified on a Conray-Ficoll and a Percoll gradient, respectively. Rat mast cells were also purified on a Percoll gradient. Superoxide anion (O2-) generation from the cells were measured by 2-methyl-6-[p-methoxy-phenyl]-3,7-dihydroimidazo[1,2-a]pyrazin+ ++-3-one (MCLA)-dependent luminescence. Addition of 0.5 mumol/l MCLA and a stimulatory agent, such as phorbol myristate acetate, N-formyl-methionyl-leucyl-phenylalanine (fMLP) and compound 48/80, to a suspension of each cell caused a marked luminescence which was inhibited by 0.5 mumol/l superoxide dismutase (SOD). Azelastine (A-5610) significantly inhibited the O2- generation from each activated inflammatory cell in a dose-dependent manner. When eosinophils were activated by fMLP in the presence of cytochalasine (CB), azelastine abolished the luminescence stronger than that from the fMLP-stimulated cells in the absence of CB.

Topics: Animals; Cytochalasin B; Eosinophils; Histamine H1 Antagonists; Humans; In Vitro Techniques; Inflammation; Luminescent Measurements; Male; Mast Cells; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Oxygen Consumption; p-Methoxy-N-methylphenethylamine; Phthalazines; Rats; Rats, Inbred Strains; Superoxides; Tetradecanoylphorbol Acetate

Complement levels and complement activation are key determinants in streptococcus-induced inflammatory responses. Activation of macrophage functions, such as complement synthesis, by group B streptococci (GBS) was examined as a possible component of GBS-induced chronic inflammation. Using an enzyme-linked immunosorbent assay, secreted C3 from mouse macrophagelike cell lines (PU5-1.8 and J774A.1) was monitored after cultivation with GBS. Whole, heat-killed GBS (1 to 10 CFU per macrophage) of both type Ia and III strains induced 25 to 300% increases in secreted C3 in both cell lines after a 24-h cultivation. GBS-treated cell lines exhibited increases in secreted lysozyme (10%) and in cellular protein (25 to 50%). Inhibition of macrophage phagocytosis by cytochalasin B inhibited GBS stimulation of C3. Purified cell walls of GBS type III strain 603-79 (1 to 10 micrograms/ml) also enhanced C3 synthesis. Local enhancement of macrophage C3 production by ingested streptococci or by persistent cell wall antigens may serve to promote chronic inflammatory responses.

Topics: Animals; Cell Line; Cell Wall; Complement C3; Cytochalasin B; Inflammation; Macrophages; Protein Biosynthesis; Streptococcal Infections; Streptococcus agalactiae

The functional similarities between C-reactive protein (CRP) and IgG raised the question as to whether human phagocytes are stimulated by CRP in the same way as by binding of antigen-complexed or aggregated IgG to their Fc receptors. Studies with the use of highly purified 125I-labeled CRP showed specific and saturable binding to human polymorphonuclear leukocytes (PMN) with a KD of 10.5 +/- 5.7 X 10(-8) M only when carried out in heat-inactivated plasma. The number of specific binding sites per cell was estimated at 1 to 3 X 10(6). Competitive inhibition of CRP binding by antigen-complexed or aggregated IgG suggests CRP binding sites to be associated with PMN Fc receptors. Only when assayed in heat-inactivated plasma did CRP binding induce adherence of cells to tissue culture dishes. However, no metabolic and potentially cytotoxic stimulation of PMN was detected during CRP plasma-dependent attachment to surfaces: induction of aggregation, release of secondary granule constituents, and activation of the hexose monophosphate pathway were not observed. These results imply that CRP-PMN interactions is dependent on an additional factor present in heat-inactivated plasma and is followed only by a complement-independent increase in PMN attachment to surfaces. Because CRP was found to be deposited at sites of tissue injury, the CRP-mediated adherence of PMN may be an important step in localizing an inflammatory focus.

Topics: Antigen-Antibody Complex; Binding, Competitive; C-Reactive Protein; Cell Aggregation; Chemotaxis, Leukocyte; Cytochalasin B; Humans; Immunoglobulin G; Inflammation; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Pentose Phosphate Pathway; Phagocytosis; Receptors, Fc

Inflammation induces the hepatic synthesis of the iron storage protein (apo)ferritin, which is released into the circulation, and behaves as an acute phase protein. The biological significance of the extracellular rise in serum (apo)ferritin is unknown. We have observed that (apo)ferritin will stimulate superoxide production from neutrophils in the presence of cytochalasin B across a physiologically appropriate concentration range. We therefore propose that extracellular ferritin has an important role in host defence against bacteraemia by stimulating oxidative metabolism.

Topics: Animals; Apoferritins; Cytochalasin B; Ferritins; Horses; Humans; Hydrogen Peroxide; In Vitro Techniques; Inflammation; Kinetics; Neutrophils; Superoxides; Synovial Fluid

Little is known about the antimicrobial potency and specificity of polymorphonuclear leucocytes which actually appear at the sites of bacterial invasion in tissues. In the present work we have compared inflammatory leucocytes induced by intraperitoneal injection of casein in rabbits with autologous peripheral blood cells in killing Escherichia coli serotype 01 and Staphylococcus aureus 502A. The results indicate that inflammatory leucocytes differ significantly from their virgin blood ancestors. While the blood leucocytes were only able to suppress the growth of the gram-negative bacteria, autologous exudative cells killed more than 95% of the test organisms within 1 h of incubation at 37 degrees C. The enhanced microbicidal activity of the inflammatory cells however, was only specific for the gram-negative bacteria, as evidenced by the failure of leucocytes to kill Staph. aureus to the same extent as the peripheral blood cells. In association with the enhanced gram-negative microbicidal activity the inflammatory cells produced chemiluminescence and released two to three times more O2-anions than the peripheral cells. We interpret these observations to mean that chemotactic factors such as casein activate inflammatory cells to increase their oxidative metabolism. Since microbicidal action of leucocytes is thought to proceed in part through oxygen-dependent reactions, the inflammatory leucocytes would be expected to effectively kill bacteria that are highly susceptible to these lethal oxygen metabolites. It cannot therefore be assumed that assessment of the functional capacity of the virgin peripheral blood PMNs would provide information on the functional characteristics of activated leucocytes which actually migrate to and accumulate at inflammatory sites.

Topics: Animals; Blood Bactericidal Activity; Chemotaxis, Leukocyte; Cytochalasin B; Escherichia coli; In Vitro Techniques; Inflammation; Luminescent Measurements; Neutrophils; Rabbits; Staphylococcus aureus; Superoxides

Experiments were performed to identify the chemoattractant for polymorphonuclear leukocytes that appears in the cerebrospinal fluid of rabbits with experimental pneumococcal meningitis. Meningitis was induced in anesthetized New Zealand white rabbits by injecting 10(4) cells of stationary-phase Streptococcus pneumoniae type III intracisternally. Before bacteria were injected, cerebrospinal fluid contained neither polymorphonuclear leukocytes nor chemotactic activity. Significant chemotactic activity for rabbit polymorphonuclear leukocytes was detected 12 h after inoculation with bacteria and was maximal after 18 to 20 h. Chemotactic activity appeared in cerebrospinal fluid while concentrations of pneumococci and total protein were increasing but before there was any accumulation of polymorphonuclear leukocytes. The chemotactic activity in cerebrospinal fluid was heat stable (56 degrees C for 30 min), eluted from Sephadex G-75 with a profile identical to that of the chemotactic activity in zymosan-activated rabbit serum, and was inhibited by treatment with antibodies to native human C5. In addition, preincubation of polymorphonuclear leukocytes with partially purified rabbit C5a selectively inhibited their subsequent chemotactic responses to cerebrospinal fluid. These data indicate that complement (C5)-derived chemotactic activity appears in cerebrospinal fluid during the course of experimental pneumococcal meningitis in rabbits and suggest that this activity accounts for the accumulation of polymorphonuclear leukocytes observed in this infection.

Topics: Animals; Cerebrospinal Fluid; Chemotaxis, Leukocyte; Complement C5; Cytochalasin B; Inflammation; Lysosomes; Meningitis, Pneumococcal; Neutrophils; Rabbits

The relationship between oxygen-radical production by rat polymorphonuclear leucocytes and O2 concentration was established by the measurement of luminol-dependent chemiluminescence at defined O2 concentrations. The O2 concentration that gave 50% of the maximum stimulated oxygen-radical production was 31 +/- 9 microM for non-opsonized latex beads and 22 +/- 9 microM for chemotactic peptide. The O2 concentration in rheumatoid synovial fluid was approx. 30 microM. It is therefore proposed that radical production at an inflammatory site may be limited by O2 concentration.

Topics: Animals; Chemotactic Factors; Cytochalasin B; Free Radicals; In Vitro Techniques; Inflammation; Latex; Luminescent Measurements; Neutrophils; Oxygen; Rats

The effects of various chemotactic factor generation conditions and several chemotherapeutic agents on neutrophil migration were determined using in vitro assay systems designed as models for inflammatory processes occurring in the synovial cavities of patients with rheumatoid arthritis. The microtubule-promoting agent concanavalin A and the microfilament-disrupting agent cytochalasin B were shown in these systems to inhibit neutrophil migration towards zymosan-activated serum-derived chemotactic factors. Neutrophils, immunoglobulin G aggregates, and serum were required for maximum generation of comparable chemotactic factors. Insoluble immunoglobulin G aggregates with or without rheumatoid factor produced more chemotactic factor activity on interaction with neutrophils than soluble immunoglobulin G aggregates. Exposure of neutrophils to supratherapeutic levels of the nonsteroidal antiinflammatory agent aspirin decreased neutrophil response to chemotactic factors while exposure to the slow-acting or immunomodulating agents gold, D-penicillamine, or azathioprine had no effect on this neutrophil function. In vitro systems employing neutrophils, insoluble aggregates, and serum may offer useful means for assaying drug effects on important functional components of the rheumatoid inflammatory process.

Topics: Antigen-Antibody Complex; Arthritis, Rheumatoid; Blood Physiological Phenomena; Chemotaxis, Leukocyte; Concanavalin A; Cytochalasin B; Humans; Immunoglobulin G; Inflammation; Macromolecular Substances; Neutrophils

The studies reviewed in this chapter provide further evidence that the secretion of lysosomal enzymes and other hydrolases is a constitutive function of certain cells whereas in other cells is an inducible process probably contributing to the pathology of a variety of diseases. Little is known of the mechanisms mediating the secretion of lysosomal enzymes. We have summarized evidence suggesting a role of microfilaments and microtubules in controlling enzyme release, but further studies of the biochemical mechanisms which control the activity of these subcellular structures are required. The fusion of lysosomes with the plasma membrane has been observed in several situations and the mechanisms underlying processes of this nature have been studied in lower organisms (Satir et al. 1973; Plattner 1974). Agents, such as concanavalin A, which interfere with the fusion of endosomes with lysosomes (Goldman 1974; Edelson and Cohn 1974a, b) should also be useful in determining the chemical nature of membrane components involved in the fusion process. New information on the fate of secreted acid hydrolases has been obtained from studies of the uptake of lysosomal enzymes by fibroblasts. Clearly, the mechanisms by which these cells endocytose secreted lysosomal enzymes will be a subject for detailed study in view of the important of directing enzymes and drugs into lysosomes (De Duve et al. 1974). The mechanisms by which extracellular inhibitors inactivate hydrolytic enzymes, particularly proteinases, is also being clarified (for review see Davies 1975) and this should aid in finding new ways for preventing tissue damage caused by the excessive secretion of these enzymes. Further investigation concerning the secretion of lysosomal enzymes should establish the essential physiological role which these enzymes play at both extracellular and intracellular sites. Also, a close examination of the interaction of both endogenous and exogenous stimuli of inflammation with cells resulting in the secretion of hydrolytic enzymes, will clarify the mechanisms underlying the initiation and progression of the inflammatory process in its diverse forms.

Topics: Animals; Anti-Inflammatory Agents; Antigen-Antibody Complex; Bone Resorption; Carrageenan; Cell Transformation, Neoplastic; Cell Wall; Complement System Proteins; Cytochalasin B; Dental Plaque; Glucuronidase; Humans; Hydrolases; Inflammation; Lysosomes; Macrophages; Microbial Collagenase; Muramidase; Neutrophils; Nucleotides, Cyclic; Plasminogen Activators; Pneumoconiosis; Streptococcus pyogenes