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PubMed2006

Essential role of neutrophils in anti-type II collagen antibody and lipopolysaccharide-induced arthritis.

In mice arthritis model induced by anti-type II collagen (CII) antibodies and lipopolysaccharide (LPS), most of cells that infiltrated into the joint space were neutrophils. To investigate the role of neutrophils in the pathogenesis of arthritis, we depleted the neutrophils in vivo by injection of the antibody against Gr-1 expressed mainly on neutrophils. The neutrophil depletion completely inhibited the arthritis development. Furthermore, neutrophil depletion in mice that had already developed arthritis ameliorated the disease. These results showed that neutrophils are indispensable not only for the development, but also for the maintenance of arthritis. Next, we tried to develop arthritis in C5-deficient mice to investigate the involvement of C5a, one of chemotactic factors for neutrophils. C5-deficient mice showed significant reduction in arthritis development in comparison with wild type mice. Injection of pertussis toxin (Ptx) into the mice, which inhibits the signals from the inhibitory G-protein coupled-receptors including the C5a receptor, suppressed the development of arthritis. Furthermore, Ptx also ameliorated the arthritis when injected into mice that had already developed the disease. These results suggest the important role of chemotactic factors involving C5a and inhibitory G-protein (Gi)-coupled receptors not only in the development, but also in the maintenance of arthritis.

Animals↗
PubMed2000

[Immunogenetic aspects in pathogenesis of acute pancreatitis].

Acute pancreatitis is characterized by essential decrease of the activity of the complement C1-C5 system components which is more marked under destructive form of the disease. The increased consumption of the components of the complement may be determined by forming immune complexes under interaction of the antibodies with structural and secretory components of the pancreas and direct proteolytic conversion under influence of trypsin. The revealed associations with HLA I antigens suggest the presence of genetic determination of the changes in the complement system. It may be also possible that components of the complement system, in particular C4 which is immune product of the HLA class III region, exert regulating influence on humoral immune reactions in acute pancreatitis.

Acute Disease↗
PubMed1980

Enhanced vascular permeability and haemorrhage-inducing activity of rabbit C5ades arg: probable role of polymorphonuclear leucocyte lysosomes.

We previously reported that the injection into rabbit skin of rabbit zymosan-activated plasma (ZAP) induces marked polymorphonuclear leucocyte (PMN) infiltration, a transient increase in vascular permeability (1 hr) and prolonged red blood cells extravasation lasting at least 10 hr. Here we describe the fractionation of ZAP to identify the factor(s) responsible for these effects. On CM Sephadex G-25 chromatography, the majority of the leucocyte-attracting, permeability-enhancing and haemorrhage-inducing activities eluted in the high-salt fractions (0 . 6 M ammonium formate, 1 M NaCl pH 5 . 0), suggesting that this is a very basic molecule(s). Furthermore, the three activities eluted in the same fraction on Sephadex G-100, with an apparent molecular weight of 14,000--17,000 daltons. These observations, and the previously described requirement for C5 in the plasma, suggest that C5ades arg is the active factor. Experiments performed in neutropenic rabbits indicated that PMN are required for both the increase in permeability and red cell extravasation. Ultrastructural studies showed extensive degenerative changes in the infiltrating PMNs evident even in 1--2-hr lesions. These ranged from 'watery' cytoplasm, loss of glycogen and cell membrane to segregation and extensive extracellular release of lysosomes. It is postulated that C5ades arg-induced chemotaxis and metabolic perturbations contribute to this rapid degeneration of the PMNs, and that the release of lysosomes from these cells results in progressive vascular injury.

Animals↗
PubMed2004

Staging the initiation of autoantibody-induced arthritis: a critical role for immune complexes.

In the K/BxN mouse model of arthritis, autoantibodies against glucose-6-phosphate isomerase cause joint-specific inflammation and destruction. We have shown using micro-positron emission tomography that these glucose-6-phosphate isomerase-specific autoantibodies rapidly localize to distal joints of mice. In this study we used micro-positron emission tomography to delineate the stages involved in the development of arthritis. Localization of Abs to the joints depended upon mast cells, neutrophils, and FcRs, but not on C5. Surprisingly, anti-type II collagen Abs alone did not accumulate in the distal joints, but could be induced to do so by coinjection of irrelevant preformed immune complexes. Control Abs localized to the joint in a similar manner. Thus, immune complexes are essential initiators of arthritis by sequential activation of neutrophils and mast cells to allow Abs access to the joints, where they must bind a target Ag to initiate inflammation. Our findings support a four-stage model for the development of arthritis and identify checkpoints where the disease is reversible.

Animals↗
PubMed1990

Potentiation of NK cytotoxicity by antibody-C3b/iC3b heteroconjugates.

The interaction of two Burkitt lymphoma lines, Raji and Rael, with human C and NK cells was analyzed. Raji cells activate the alternative C pathway (ACP) and then bind C3 fragments. Consequently, the cells become more sensitive to lysis by CR3-bearing NK cells but not to C lysis. In contrast, Rael cells are poor ACP activators, do not bind C3 fragments, and are therefore resistant to C-dependent NK lysis. As suggested earlier, the difference between Raji and Rael could be attributed to the presence or absence of CR2, respectively, on their surface. To potentiate C- and NK-dependent lysis of target cells, we generated heteroconjugates composed of a murine antitransferrin receptor mAb and of human C C3b or iC3b. Antibody-C3b conjugates induced C3 deposition on Rael cells and elevated C3 deposition on Raji cells in human serum. Both Raji and Rael cells coated with antibody-C3b conjugates were efficiently lyzed by the cytolytic ACP in human serum. This conjugate had a small enhancing effect on target cell lysis by NK cells which could be markedly increased by combined treatment of the target cell with antibody-C3b conjugate and C5-depleted human serum. On the other hand, antibody-iC3b conjugates efficiently potentiated lysis of target cells by NK cells in the absence of serum. The iC3b-directed cytotoxicity was mediated by CR3-bearing NK effector cells. Anti-C3 but not anti-mouse Ig antibodies abrogated the activity of the antibody-iC3b conjugate. These results further demonstrate that NK cytotoxicity may be potentiated by opsonizing the target cells with C3 fragments and suggest that antibody-C3b/iC3b conjugates could be potent tools for targeting and potentiation of the lytic action of both C and NK cells against tumor cells.

Antigen-Antibody Complex↗
PubMed1978

The influence of chemotactic factors on neutrophil adhesiveness.

The ability of several chemotactic factors to alter polymorphonuclear neutrophil (PMN) adhesiveness to nylon fibers was studied. Partly purified bacterial chemotactic factor, the isolated chemotactic fragment of human C5, and the chemotactic synthetic tripeptide, formyl-methionyl-leucyl-phenylalanine, transiently enhanced the nylon fiber adhesiveness of rabbit peritoneal PMSs. The capacity of these chemotactic factors to augment PMN adherence closely paralleled their ability to aggregate PMNs in suspension and to induce neutropenia when infused into rabbits. However, at least a portion of the adhreence-augmenting capacity of these agents was independent of their ability to induce PMN aggregation. Thus, chemotactic factors appear to transiently enhance PMN adhesiveness to a variety of surfaces. This hyper-adhesiveness may underlie the augmented nylon fiber adherence, aggregation, and neutropenia induced by these factors.

Animals↗
PubMed1987

Non-steroidal anti-inflammatory drugs: how do they work?

Current dogma holds that non-steroidal anti-inflammatory drugs (NSAIDs) act by inhibition of the synthesis and release of prostaglandins. However, NSAIDs also inhibit the activation of neutrophils, which provoke inflammation by releasing products other than prostaglandins. We now report that NSAIDs (for example, indomethacin, piroxicam) inhibit activation of neutrophils by inflammatory stimuli such as C5-derived peptides and leukotriene B4 even when cyclooxygenase products generated in suspensions of stimulated neutrophils (prostaglandin E and thromboxanes) are present. Sodium salicylate (3mM) greatly inhibited aggregation of neutrophils but had no effect on aggregation of platelets or production of thromboxane induced by arachidonate. Sodium salicylate and other NSAIDs also inhibit calcium movements (45Ca uptake, changes in fluorescence of chlortetracycline and Quin-2). Aspirin, sodium salicylate, indomethacin, and piroxicam also enhanced the post-stimulation rise in intracellular cyclic AMP. NSAIDs therefore inhibit early steps in neutrophil enhance intracellular levels of cyclic AMP.

Adult↗
PubMed1979

Inhibition of neutrophil chemotaxis in association with experimental angioedema in patients with cold urticaria: a model of chemotactic deactivation in vivo.

Deactivation is a phenomenon in which leucocytes exposed in vitro to a chemotactic factor in the absence of a concentration gradient are rendered relatively unresponsive to stimulation by a subsequent chemotactic gradient. In patients with idiopathic cold-induced urticaria, the elicitation of a local experimental angioedematous lesion causes the release of two chemotactic principles previously shown to deactivate leucocytes in vitro, high molecular weight neutrophil chemotactic factor (HMW-NCF) and eosinophil chemotactic factor of anaphylaxis (ECF-A), into the venous circulation draining the challenged extremity. However, biopsy specimens of lesional skin sites obtained for up to 24 hr show no infiltration of cells. For this reason, the in vitro chemotactic responsiveness of neutrophils to the chemotactic factor HMW-NCF and C5 fragments were assessed in three patients at various times after experimental challenge. Leucocytes from venous effluent draining an experimentally-induced angioedematous lesion were markedly impaired in their chemotactic responsiveness to both chemotactic factors 5 min after challenge, while cells taken from an unchallenged extremity at the same time responded normally. Cells from both arms were equally impaired in their responsiveness 1 hr later, thereby demonstrating that the chemotactic defect becomes systemic. The acquired defect was dissipated 4 hr after challenge. These data suggest that deactivation may occur in vivo and may alter host responsiveness in states where chemotactic factors are released into the circulation.

Angioedema↗
PubMed1992

Mycobacterial infection primes T cells and macrophages for enhanced recruitment of neutrophils.

C57BL/6 mice intraperitoneally infected with Mycobacterium bovis BCG (substrain Pasteur) recruited significantly higher numbers of neutrophils after an intraperitoneal inoculation of either BCG protein antigen or of endotoxin than uninfected control mice. Antigen-induced neutrophil recruitment was mediated by T cells of both CD4+ and CD8+ phenotype and was also observed in the C5-deficient DBA/2 mouse strain. The adoptive transfer of immune serum did not prime mice for enhanced antigen-mediated recruitment of neutrophils. The endotoxin-mediated recruitment of neutrophils was also enhanced in infected as compared to uninfected DBA/2 mice. Finally, endotoxin-pulsed purified macrophages from infected C57BL/6 mice recruited higher numbers of neutrophils than endotoxin-pulsed macrophages from normal mice in an adoptive transfer to peritoneal cavities of naive recipient mice. These data show that during mycobacterial infection, T cells and macrophages are primed for recruitment of neutrophils after being triggered in specific or nonspecific ways. This may represent a means to cope with secondary infections by allowing for extensive neutrophil infiltration readily upon microbial challenge.

Animals↗
PubMed1985

Modes of action of aspirin-like drugs.

Current dogma holds that nonsteroidal anti-inflammatory drugs (NSAIDs) act by inhibition of the synthesis and release of prostaglandins. However, NSAIDs also inhibit the activation of neutrophils, which provoke inflammation by releasing products other than prostaglandins. We now report that NSAIDs (e.g., indomethacin, piroxicam) inhibit activation of neutrophils by inflammatory stimuli, such as C5-derived peptides and leukotriene B4, even when cyclooxygenase products generated in suspensions of stimulated neutrophils (prostaglandin E and thromboxanes) are present. Sodium salicylate (3 mM) greatly inhibited aggregation of neutrophils but had no effect on aggregation of platelets or production of thromboxane induced by arachidonate. Sodium salicylate and other NSAIDs also inhibit calcium movements (45Ca uptake, changes in fluorescence of chlortetracycline and quin-2). Aspirin, sodium salicylate, indomethacin, and piroxicam also enhanced the poststimulation increase in intracellular cyclic AMP. NSAIDs therefore inhibit early steps in neutrophil activation as reflected by their capacity to inhibit movements of Ca and to enhance intracellular levels of cyclic AMP.

Anti-Inflammatory Agents↗
PubMed1981

Enhancement of basophil chemotaxis in vitro by virus-induced interferon.

It is well established that viral infections may precipitate or worsen attacks of bronchial asthma. Furthermore, in symptomatic atopic subjects, the local accumulation of basophils and the production of a basophil chemotactic factor have been reported. We have investigated the effect of cell-free supernates from viral stimulated cultures of human mononuclear cells on the in vitro migration of human basophils. Our results show the presence of a factor in these culture supernates that enhances the migration of basophils toward two separate chemoattractants, a peptide from C5 and a lymphokine. The enhancing activity, while affecting basophil migration, did not change the response of monocytes. The enhancing activity resembled viral-induced interferon when (a) pH 2 stability, (b) heat resistance, (c) trypsin sensitivity, and (d) species-specificity were compared. Finally, the enhancing activity for basophil chemotaxis and the interferon titer were highly correlated in preparations with a 10(4)-fold difference in interferon specific activity. Our studies show that viral-induced interferon can augment the in vitro chemotactic response of basophils. Because mediators present in basophils may be involved in the pathogenesis of immediate hypersensitivity, the modulation of basophil movement by interferon suggests a possible mechanism for the association between viral infections and atopic disorders.

Animals↗
PubMed1991

Structural aspects of the human C5 gene. Intron/exon organization, 5'-flanking region features, and characterization of two truncated cDNA clones.

Human C5 cDNA fragments were used to identify five overlapping cosmid clones that spanned the entire C5 gene. Partial sequencing and Southern analysis of the clones were performed to identify intron/exon boundaries and to map intron size. The human C5 gene is 79 kilobases in length and is comprised of 41 exons. Comparison of C5 with the homologous family members C3 and C4 revealed striking similarities in exon size and number. Less, although significant similarities were also observed with the family member alpha 2-macroglobulin. The transcriptional start site for the C5 gene was observed as a doublet at positions 29 and 28 nucleotides upstream of the ATG start codon. The 5'-flanking region of the gene contains sequences homologous with several known responsive elements, including interferon, interleukin-6, glucocorticoid, estrogen, NF-kappa B, and HNF-1. Two previously identified truncated cDNAs, pHC5A and pHC5B, contain 21 and 16 exons, respectively. The last exon in pHC5A, designated exon 21a, is a product of alternative splicing and is not present in the major full-length transcript. Truncation of pHC5A is the result of an alternative polyadenylation signal located in exon 21a. In pHC5B, exon 16 is extended on the 3' end by additional flanking genomic sequence that also contains an alternative polyadenylation signal.

Animals↗
PubMed1981

Autolytic fragmentation of complement components C3 and C4 under denaturing conditions, a property shared with alpha 2-macroglobulin.

The alpha polypeptide chain of the complement protein C3 splits into two fragments of 74 000 and 46 000 apparent mol.wt. under certain conditions used to prepare the protein for SDS (sodium dodecyl sulphate)/polyacrylamide-gel electrophoresis. The cleavage reaction occurs over a wide range of temperatures and from pH 4.6 to 10.6 in the presence of denaturants such as urea, SDS and guanidine hydrochloride. It is also induced by heat-denaturation of C3 in the absence of chemical denaturants. The reaction occurs only with haemolytically active C3, and is not observed with hydroxylamine-inactivated C3 or with C3b. A similar cleavage of the alpha-chain of complement component C4 occurs under the same conditions, forming fragments of 53 000 and 41 000 apparent mol.wt. This reaction is again specific for haemolytically active C4, and does not occur with C4b or hydroxylamine-inactivated C4. The complement component C5, although structurally similar to C3 and C4, does not undergo a reaction of this type. The characteristics of the denaturation-induced cleavage of C3 and C4 match those described for the 'heat-induced' cleavage of alpha 2-macroglobulin [Harpel, Hayes & Hugli (1979) J. Biol. Chem. 254, 8669-8678]. Cleavage of alpha 2-macroglobulin is also specific for the active form of the protein, and does not occur with chemically inactivated or proteinase-cleaved forms. The unusual conditions and specificity of the peptide-bond cleavage in all three proteins suggest that it is an autolytic process rather than being the result of trace proteinase contamination. The active forms of C3, C4 and alpha 2-macroglobulin have the transient ability to form covalent bonds after activation. The autolytic cleavage reaction is likely to be related to the covalent-bond-forming reactions of these proteins.

Complement C3↗
PubMed1997

Sublytic concentrations of the membrane attack complex of complement induce endothelial interleukin-8 and monocyte chemoattractant protein-1 through nuclear factor-kappa B activation.

Activation of the complement cascade and subsequent assembly of the membrane attack complex (MAC) occur in a number of pathophysiological settings. When formed on the surface of endothelial cells in sublytic concentrations, the MAC can induce a number of proinflammatory activities, including the secretion of soluble mediators (eg, interleukin (IL)-8 and monocyte chemoattractant protein (MCP)-1) and the up-regulation of cell surface adhesion molecules. Available data indicate that MAC-induced cell activation may occur through several complex signal transduction pathways, but little is known about the intranuclear mechanisms by which complement-derived products promote the up-regulation of inflammatory mediators. Using purified distal complement proteins (C5-9) to assemble functional MAC on early-passage human umbilical vein endothelial cells (HUVECs), we examined mechanisms of MCP-1 and IL-8 induction. Formation of sublytic concentrations of MAC promoted an increase in nuclear factor (NF)-kappa B DNA binding activity within 60 minutes as determined by serial electrophoretic mobility shift assay. Cytosolic to nuclear translocation of NF-kappa B was confirmed by Western immunoblot and immunocytochemical analyses. Formation of the C5b-8 complex also promoted NF-kappa B translocation but to a lesser degree than observed in HUVECs containing complete MAC. No cytosolic to nuclear translocation of the p65 NF-kappa B subunit was observed in unstimulated HUVECs or in cells incubated with the MAC components devoid of C7. Preincubation of HUVECs with pyrrolidine dithiocarbamate prevented MAC-induced increases in IL-8 and MCP-1 mRNA concentrations and protein secretion. A direct cause and effect linkage between MAC assembly and NF-kappa B activation was established through examination of the pharmacological effect of the peptide SN50 on IL-8 and MCP-1 expression. SN50 is a recently engineered 26-amino-acid peptide that contains a lipophilic cell-membrane-permeable motif and a nuclear localization sequence that specifically competes with the nuclear localization sequence of the NF-kappa B p50 subunit. This study provides direct in vitro evidence that the distal complement system (MAC) can promote proinflammatory endothelial cell activation, specifically, increases in IL-8 and MCP-1 mRNA concentrations and protein secretion, and that cytosolic to nuclear translocation of NF-kappa B is necessary for this response.

Blotting, Northern↗
PubMed1978

The mechanism of basophil histamine release in patients with periodontal disease.

Histamine release from washed peripheral blood basophils of thirty-three subjects with varying degrees of periodontal disease was studied. Dental plaque, serum and basophil leucocytes were collected from individual patients. There was no histamine release when autologous, washed sonicated plaque was added to leucocytes. However, the incubation of autologous plaque with serum at 37 degrees C for 30 min generated a factor which induced histamine release from basophils. This serum factor was stable to heat (56 degrees C, 30 min), eluted from a Sephadex G-100 column at a volume corresponding to a molecular weight of approximately 16,000 daltons and its action was inhibited by antibody to C5. This factor, therefore, is probably C5a. There was a variation in the degree of histamine release seen with the leucocytes of different donors. This variability was a property of the basophil rather than a function of the serum. Basophils from patients with gingival indices of 0.5 to 1.0 had significantly more histamine release than basophils from patients with gingival indices of less than 0.5 or greater than 1.5 (P less than 0.001). These experiments demonstrate that dental plaque activates serum to form C5a which in turn releases histamine from basophils. However, these experiments do not indicate a role for IgE in this reaction since the direct interaction of plaque with basophils did not cause histamine release. The release of mediators from mast cells could play an important role in the induction of the inflammatory response in periodontal disease.

Adolescent↗
PubMed1975

Release of histamine from rat mast cells by the complement peptides C3a and C5a.

Suspensions of rat mast cells were used to study the histamine-releasing actions of anaphylatoxins C3A and C5a in vitro. The peptides, derived from human or porcine complement proteins C3 and C5, were less potent than 48/80 but more potent than bradykinin in stimulating release of histamine from mast cells. The pattern of release resembled that of the anaphylactic release action, e.g. release was limited to less than 30 per cent of the cell histamine, the reaction was calcium-dependent and was potentiated by phosphatidyl serine. When C3a and C5a were added together to mast cell suspensions, the amount of histamine released was additive. Similarly, release by either peptide combined with bradykinin was additive. Histamine-releasing activity (as well as smooth muscle-stimulating activity) was abolished when the peptides were treated with pancreatic carboxy-peptidase B. Active or inactive peptides were bound by mast cells and addition of active C3a in combination with the inactive, des-arginine derivative, C3ai, resulted in partial inhibition of histamine release.

Anaphylaxis↗
PubMed1985

Suppression of mouse complement activity by contaminants of technical grade pentachlorophenol.

Pentachlorophenol (PCP) is an antimicrobial agent used chiefly for the preservation of wood. Subchronic oral exposure (14 days) to Technical Grade PCP significantly inhibited the functional activity of female B6C3F1 mouse complement when measured in a microtiter hemolytic assay. When evaluated one day following the final exposure the highest administered dose (100 mg/kg) significantly suppressed the Classical complement pathway, the Spontaneous C1 autoactivation pathway, the Alternate pathway and the level of complement component, C3. Reconstitution studies using C5-deficient serum also demonstrated deleterious effects on this complement component. The Classical pathway was the most sensitive to Technical Grade PCP effects. Animals treated with 100 mg/kg Technical Grade PCP had CH 50 levels 30% of vehicle controls. Animals treated for 14 days and allowed a 15 day recovery period had CH 50 values 36% of control and animals which recovered for 30 days had only 52% of the complement activity of control animals. C3 recovery studies also demonstrated continued suppression on days 15 and 30 post-final exposure. Doses of 10 and 30 mg/kg did not produce the marked effects observed with the highest dose; however, a dose-dependent trend was observed for all responses. Animals treated with 100 mg/kg of EC-7, a PCP preparation with reduced amounts of contaminating dioxins and dibenzofurans, did not demonstrate detrimental effects on the complement system.

Animals↗
PubMed1978

Observations on the evolution of idiopathic rapidly progressive glomerulonephritis.

Distinctive deposits of C3, C5 and properdin were identified in the minimally proliferative glomerular lesions of a patient with idiopathic rapidly progressive glomerulonephritis. Biopsies of her renal allograft at times of recurrences of her disease and of five other patients with progressive renal failure but less severe crescent formation showed deposits identical composition and position, giving evidence of a common pathogenesis. The deposits were subepithelial and located in that part of the basement membrane in apposition to the mesangium (capillary waist). Breaks in the basement membrane were often exclusively in this area suggesting the deposits were causative. Ancillary observations suggest that the subepithelial deposits become unidentifiable after the scarring of severe extracapillary proliferation develops. Three of the patients had, in addition, intramembranous dense deposits but in other ways their disease was not characteristic of membranoproliferative glomerulonephritis Type II. Instead, the evidence indicated that all six patients were in early or lage stages of idiopathic (non-streptococcal) rapidly progressive glomerulonephritis.

Basement Membrane↗