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PubMed1982

Inhibition of zymosan-induced alternative complement pathway activation by concanavalin A.

Zymosan, a polysaccharide composed primarily of glucan and mannan residues, activates the complement system through the alternative complement pathway. We showed that zymosan-induced complement activation is inhibited by zymosan-bound lectins with carbohydrate specificities for mannosyl and glycosyl residues. Lectins unable to bind mannosyl or glucosyl residues did not inhibit zymosan-induced complement activation.

Complement Activation↗
PubMed1988

Stimulation of neutrophil actin polymerization and degranulation by opsonized and unopsonized Candida albicans hyphae and zymosan.

We previously showed that unopsonized Candida albicans hyphae stimulated a delayed rise in the putative neutrophil second messengers Ca2+ and inositol 1,4,5-trisphosphate and subsequent O2- release, as compared with opsonized hyphae or zymosan. Therefore, cytoskeletal and degranulation temporal responses to these stimuli were examined. Unopsonized zymosan elicited no neutrophil responses under the experimental condition used. Neutrophil actin polymerization (quantitated by fluorescent measurements of NBD phallacidin) was rapid after stimulation by opsonized hyphae or zymosan (peaking at 1 and 2 min, respectively). This corresponded to observed changes in microscopic actin polymerization, measured with rhodamine phalloidin, which progressed from initially diffuse to collarlike to cylinderlike staining patterns surrounding the hyphae. Compared with opsonized hyphae, unopsonized hyphae resulted in a delayed appearance of the last two visible patterns (P less than 0.05) and in quantitative actin polymerization despite similarly rapid initial contact and spreading over the hyphae by neutrophils. Unlike other neutrophil responses, degranulation did not follow the delayed patterns of responses to stimulation with unopsonized hyphae. In the absence of the release of the cytoplasmic marker lactate dehydrogenase, the release of beta-glucuronidase, an azurophil granule marker, gradually and progressively rose in response to all of the stimuli but unopsonized zymosan. The low but significant levels observed were within a range consistent with published results for degranulation responses to particulate stimuli without cytochalasin B. A quantitative immunoassay of lactoferrin, a specific granule marker, detected no release into supernatants, and immunofluorescent staining indicated concomitant depletion of lactoferrin from neutrophil granules and binding to hyphal and neutrophil surfaces after stimulation by unopsonized hyphae. Thus, the delayed actin polymerization response to unopsonized hyphae occurred subsequent to neutrophil attachment and spreading and resembled the temporal sequence of other neutrophil responses linked to the respiratory burst. In contrast, the degranulation responses to all stimuli appeared to begin and progress gradually after observed attachment and spreading of the neutrophil over hyphal surfaces without a clear temporal relationship to rises in cytoplasmic Ca2+ or F-actin. In addition, the avid binding of released lactoferrin to cell surfaces eliminates its value as a quantitative marker of enzyme release but raises the possibility that it might participate in fungicidal activity.(ABSTRACT TRUNCATED AT 400 WORDS)

Actin Cytoskeleton↗
PubMed1992

Intestinal smooth muscle dysfunction after intraperitoneal injection of zymosan in the rat: are oxygen radicals involved?

Zymosan is frequently used as an activator of granulocytes to study inflammatory responses. We used zymosan as a model to understand the mechanisms involved in intestinal inflammatory diseases, and our special interest was focused on the smooth muscle function. Moreover, we investigated the role of oxidative stress in intestinal pathology after inflammatory processes. Intraperitoneal injection of zymosan induces a peritoneal inflammation, characterised by exudate in the peritoneum and peritoneal fibrosis. Three days after injection of zymosan (25-40 mg/100 g) we measured a decreased beta adrenergic smooth muscle response, while the muscarinic receptor-mediated contraction was not significantly affected. Efforts were made to correlate these observations with the development of oxidative stress; however, the intestinal glutathione balance remained undisturbed and no increase in lipid peroxidation products in the intestine was observed. Our conclusion is the peritoneal inflammation will lead to a release of various mediators, which may destroy receptor systems, among which are beta adrenoceptors. There was no evidence of an important role for reactive oxygen metabolites in this effect.

Animals↗
PubMed2001

Anti-inflammatory effects of somatostatin analogs on zymosan-induced earlobe inflammation in mice: comparison with dexamethasone and ketoprofen.

The aim of the present study was the estimation of the anti-inflammatory effects of the somatostatin analogs, octreotide (OCT) and vapreotide (RC-160), in zymosan-induced mice ear inflammation and to compare their effects with those of the glucocorticoid dexamethasone (DX) and the non-steroid anti-inflammatory drug ketoprofen (KP), which are the well-known and potent suppressors of the inflammatory reaction. The inflammation was induced by injecting 20 microl of 1% suspension of zymosan intradermally into one of the earlobes of the mouse. The control animals received a vehicle 0.9% NaCl. The zymosan-treated animals were injected subcutaneously with one of the following substances: 0.9% NaCl, OCT, RC-160, DX, KP or with OCT plus DX and OCT plus KP. The edema of earlobes, the area of inflammatory focus and the area of vascular profiles in the inflamed tissues were estimated. A reduction of the ear edema in the mice treated with OCT, DX, KP, OCT + DX and OCT + KP was observed. The administration of all drugs caused the decrease of the area of the inflammatory focus and of the area of vascular profiles. The antiphlogistic activity was more pronounced in the OCT-treated animals in comparison to those treated with RC-160. The joint treatment with either OCT plus DX or OCT plus KP almost totally inhibited the zymosan-induced inflammatory reaction. In summary, the somatostatin analog OCT possesses antiphlogistic activity roughly comparable with classical anti-inflammatory drugs such as DX and KP. The somatostatin analogs may constitute a new promising group of anti-inflammatory agents.

Analgesics↗
PubMed1981

The role of complement and IgG on zymosan opsonization.

Zymosan particles require opsonization for optimal interaction with granulocytes and activation of their respiratory burst. In the present study we evaluated the serum factors necessary for zymosan opsonization. First, zymosan was treated with either normal serum or hypogammaglobulinemic serum (HGS), which is deficient in immunoglobulins (Ig) but has a normal concentration of complement components. Using granulocyte chemiluminescence to assay opsonization, the activity of particles treated with HGS was 66 +/- 1.9% (mean +/- SEM) of that with normal serum (p less than 0.001), suggesting a role of Ig. HGS opsonic activity was restored to normal when the particles were also treated with IgG; however, neither heat-inactivated normal serum (56 degrees C, 30 min) nor pure human IgG alone had opsonic activity. The roles of the classical (CCP) and alternative (ACP) pathways of the complement system were also investigated. ACP activity seemed essential, since inactivation of the ACP (50 degrees C, 30 min) eliminated the activity of normal serum. However, when the ACP was intact, CCP action appeared to participate in opsonization, since selective CCP inactivation with EGTA and MgCl2 reduced the opsonic activity of normal serum by 26 +/- 3.3% (p less than 0.005). Thus, it is concluded that the ACP, CCP, and IgG all participate in zymosan opsonization.

Agammaglobulinemia↗
PubMed1990

Macrophages cultured in vitro release leukotriene B4 and neutrophil attractant/activation protein (interleukin 8) sequentially in response to stimulation with lipopolysaccharide and zymosan.

The capacity of lipopolysaccharide (LPS), zymosan, and calcium ionophore A23187 to induce neutrophil chemotactic activity (NCA), leukotriene B4 (LTB4), and neutrophil attractant/activation protein (NAP-1) release from human alveolar macrophages (AM) retrieved from normal nonsmokers was evaluated. LPS induced a dose-dependent release of LTB4 that began by 1 h, 4.0 +/- 3.2 ng/10(6) viable AM; peaked at 3 h, 24.7 +/- 13.5 ng/10(6) viable AM; and decreased by 24 h, 1.2 +/- 1.0 ng/10(6) viable AM (n = 8). Quantities of LTB4 in cell-free supernatants of AM stimulated with LPS were determined by reverse-phase high-performance liquid chromatography and corresponded well with results obtained by radioimmunoassay. By contrast, NAP-1 release began approximately 3-5 h after stimulation of AM with LPS, 197 +/- 192 ng/ml, and peaked at 24 h, 790 +/- 124 ng/ml. Release of NAP-1 was stimulus specific because A23187 evoked the release of LTB4 but not NAP-1, whereas LPS and zymosan induced the release of both LTB4 and NAP-1. The appearance of neutrophil chemotactic activity in supernatants of AM challenged with LPS for 3 h could be explained completely by the quantities of LTB4 present. After stimulation with LPS or zymosan for 24 h, AM had metabolized almost all generated LTB4. Preincubation of AM with nordihydroguiaretic acid (10(-4) M) completely abolished the appearance of NCA, LTB4, and NAP-1 in supernatants of AM challenged with LPS. Therefore, LPS and zymosan particles were potent stimuli of the sequential release of LTB4 and NAP-1 from AM.

Calcimycin↗
PubMed1982

Superoxide-dependent chemotactic activity for PMNs derived from opsonized zymosan-stimulated human platelets.

Previous studies have shown that platelets exhibit a H2O2 producing, NADH-dependent system that is activated by interaction with particulate material. Current evidence suggests that this system could be critically involved in th generation of chemotactic factor(s). In the present studies, chemotactic activity for polymorphonuclear leukocytes of supernatants derived from zymosan-stimulated human platelets has been evaluated using an agarose gel technique. Supernatants of opsonized zymosan-stimulated platelets showed significant chemotactic activity (migration index = 300 +/- 50), in comparison with supernatants prepared from platelet suspensions stimulated with nonopsonized-zymosan (migration index = 10 +/- 15) or resting platelet supernatants (migration index = 15 +/- 15). Furthermore, a marked increase in chemotactic activity of the opsonized zymosan-treated platelet supernatants was demonstrated after the addition of NADH (migration index = 525 +/- 100). The inclusion of specific inhibitors of the cycloxygenase and lipoxygenase pathways resulted in a marked reduction of chemotactic activity, which was restored in the presence of NADH. Further, the addition of superoxide dismutase completely abolished the chemotactic response induced by NADH. These data suggest that platelets are the source of chemotactic factor(s) derived from the activation of a superoxide generating system.

Blood Platelets↗
PubMed1985

Effect of age-dependent enzymatic degradation of zymosan into oligosaccharides during incubation with serum on its opsonization by complement.

Incubation of zymosan particles with serum was shown to be accompanied by their partial breakdown into the oligosaccharides maltose, maltotriose, and maltotetraose, that were quantified under the form of glucose after degradation by alpha-glucosidase. Incubation with normal adult serum yielded twice as much glucose than incubation with cord serum. The degradation of zymosan could be mimicked by incubation with purified pancreatic alpha-amylase. A correlation was also found between the amount of oligosaccharides released from the particles during their incubation with serum and the concentration of amylase in the sera. The latter is low in newborns and increases several-fold, to nearly adult levels, at 3-6 months of age. Preincubation of zymosan with purified pancreatic alpha-amylase resulted in an approximately 50% increase in the binding of radioactive anti-C3c in the supernates obtained after subsequent incubation with cord serum but not with adult serum. With six of 24 cord sera, but not with adult serum, it also resulted in an augmentation of the chemiluminescence accompanying the phagocytosis of the particles after their opsonization. It is concluded that the relative inefficiency of cord and newborn serum in opsonizing zymosan is attributable not only to their lower content of the components of the alternative pathway of complement, but also to a lower concentration of serum amylase.

Adult↗
PubMed2006

Selective regulation of IL-10 signaling and function by zymosan.

Balanced activity of pro- and anti-inflammatory cytokines during innate immune responses is required to allow effective host defense while avoiding tissue damage and autoimmunity. Induction of cytokine production after recognition of pathogen-associated molecular patterns (PAMPs) by innate immune cells has been well demonstrated, but modulation of cytokine function by PAMPs is not well understood. In this study we show that stimulation of macrophages with zymosan, which contains PAMPs derived from yeast, rapidly extinguished macrophage responses to IL-10, a suppressive cytokine that limits inflammatory tissue damage but also compromises host defense. The mechanism of inhibition involved protein kinase Cbeta and internalization of IL-10R, and was independent of TLR2 and phagocytosis. Inhibition of IL-10 signaling and function required direct contact with zymosan, and cells in an inflammatory environment that had not contacted zymosan remained responsive to the paracrine activity of zymosan-induced IL-10. These results reveal a mechanism that regulates IL-10 function such that antimicrobial functions of infected macrophages are not suppressed, but the activation of surrounding noninfected cells and subsequent tissue damage are limited. The fate of individual cells in an inflammatory microenvironment is thus specified by dynamic interactions among host cells, microbes, and cytokines that determine the balance between protection and pathology.

Animals↗
PubMed2000

Generation of pro-inflammatory and anti-inflammatory cytokines in the gut in zymosan-induced peritonitis.

In major systemic inflammation such as severe peritonitis, various pro-inflammatory cytokines, such as TNF-alpha, IL-1 beta and IL-6, play important roles in the development of multiple organ dysfunction syndrome (MODS). The purpose of this study was to investigate the outflow of pro-inflammatory and anti-inflammatory cytokines from the efferent mesenteric lymphatic vessels under peritonitis. Mesenteric lymph samples were collected from adult male rats at 2, 4, 6, 8 and 10 hr after an intraperitoneal injection of zymosan at a dosage of 0.1 mg/g (non-lethal dose) or 0.5 mg/g (lethal dose). Blood samples were obtained at 10 hr after zymosan administration. The amounts of drained TNF-alpha and IL-6 in the lymph peaked at 2-4 hr and 4-8 hr after zymosan administration, respectively. The amounts of drained IL-10 in the lymph gradually increased until 10 hr. The amounts of drained TNF-alpha and IL-10 in the mesenteric lymph were significantly correlated with the dosage of zymosan. In conclusion, under intraperitoneal inflammation, pro-inflammatory cytokines (TNF-alpha and IL-6) increased in the mesenteric lymph and were drained into circulation. IL-10, one of the anti-inflammatory cytokines, also increased in the mesenteric lymph after several hours' delay and its increase was remarkable in several inflammations. These findings suggested that the gut might be one of the pro-inflammatory and anti-inflammatory cytokine-generating organs under peritonitis. The lymph-drained amounts of each cytokine under peritonitis are considered to differ with the time or severity of inflammation, which may cause different conditions in patients due to the imbalance of pro-inflammatory and anti-inflammatory cytokines.

Animals↗
PubMed1975

Binding of the complement intermediate C56 to zymosan in acute phase human sera.

C56 is known to appear in the fluid phase when zymosan is incubated at 37 degrees C with certain acute phase 'reactor' sera. In the present study, C56 was detected bound to the zymosan particle prior to its appearance free in solution. In reactor sera C56 was formed and released with kinetics similar to that of the generation and decay of a C56-binding site formed when zymosan was incubated with normal serum. Bound and fluid phase C56 was detected only in reactor sera, and was generated only by agents known preferentially to activate the properdin pathway. Elution of C56 from zymosan in hypertonic salt solutions proved to be a convenient step in the partial purification of large amounts of this haemolytically active bimolecular complex.

Binding Sites↗
PubMed1975

Platelet function in C6-deficient rabbits. Aggregation and secretion induced by collagen and zymosan.

Platelet aggregation and the selective release of 5-hydroxytryptamine (5HT) and adenine nucleotides were measured in platelet-rich plasma (PRP) and washed platelet suspensions from control and C6-deficient rabbits. Aggregation and release induced by collagen were similar in both groups of animals. Aggregation responses to zymosan in control PRP samples were biphasic, and only the second phase was associated with release. In C6-deficient PRP samples, zymosan-induced aggregation lacked the second phase and there was no release of 5HT or adenine nucleotides. Zymosan induced no aggregation in washed platelet suspensions unless cell-free plasma was also added. C6-deficient plasma supported only primary aggregation, but the addition of control plasma resulted in biphasic aggregation and release. Zymosan which had been pre-activated in control or C6-deficient cell-free plasma induced primary aggregation in washed platelet suspensions. To obtain secondary aggregation and release, the addition of control plasma to the platelet suspension was necessary.

Adenine Nucleotides↗
PubMed1976

Increased erythropoietin production in anephric rats with hyperplasia of the reticuloendothelial system induced by colloidal carbon or zymosan.

Adult rats were subjected sequentially to (1) administration of colloidal carbon, zymosan, or gadolinium; (2) subtotal hepatectomy, bilateral nephrectomy, or sham operation; and (3) a 6-hr bout of hypoxia, starting 1 hr or 24 hr after the operation. Control animals received the respective vehicles. The erythropoietin (Ep) activity was assayed in exhypoxic polycythemic mice on the basis of 48-hr per cent RBC(-59) Fe incorporation values. Ep levels in serum of anephric rats primed with either colloidal carbon or zymosan were considerably more elevated than in control animals. This potentiating effect was observed in rats subjected to hypoxia starting either 1 or 24 hr after nephrectomy. On the other hand, gadolinium did not enhance the extrarenal Ep response to hypoxia. It is emphasized that both colloidal carbon and zymosan induced marked hyperplasia of the hepatic and splenic reticuloendothelial system (RES), while gadolinium did not induce this effect. A strict correlation was thus established between potentiation of extrarenal Ep production and hyperplasia of the RES. It is therefore tentatively concluded that the RES is a source of extrarenal Ep. Additionally, since the liver plays a prominent role in extrarenal Ep production, Kupffer cells may represent a major source for Ep in the anephric rat. Finally, it is of interest that both colloidal carbon and zymosan did not potentiate the Ep response to hypoxia in sham-operated or subtotally hepatectomized rats.

Animals↗
PubMed1991

A comparative study of the cellular, exudative and histological responses to carrageenan, dextran and zymosan in the mouse.

A murine 6-day air-pouch model of inflammation has been developed and used to compare the patterns of acute and chronic inflammatory response to three irritants, carrageenan, dextran and zymosan, each injected into the cavity of the pre-formed pouch. The inflammation was assessed by measurement of exudate volume and numbers of infiltrating leucocytes over a 30-day time course. Histological changes in the inflamed air-pouch lining tissue were also investigated. The inflammatory response to carrageenan was acute with moderate exudate formation and cell numbers. Dextran produced a mild inflammatory reaction with low cell infiltration into exudate. In contrast, the inflammatory response to zymosan was greater in terms of cell migration, but smaller in terms of exudate volume and occurred later in the time course. Histological changes in the inflamed air-pouch tissue were also markedly different in response to the three irritants. Carrageenan induced a rapid, mainly polymorphonuclear leucocyte (PMN) infiltrate into the tissue and deposition of fibrin on the luminal surface. The response to dextran was characterized by a rapid resolution of the inflammatory response, with fewer leucocytes present in the lining and no fibrin deposition. In contrast, zymosan caused a marked but slower leucocyte influx, with greater numbers of monocytes, and clearance of the zymosan particles from the air-pouch lining by macrophages. This study indicates that by using different irritants to produce inflammation, it may be possible to dissect the roles played by various cells and inflammatory mediators during acute and chronic inflammation.

Animals↗
PubMedDate not supplied

Involvement of platelet-activating factor in the hypotensive response to zymosan in rats.

In anaesthetised rats, intravenous injection of zymosan induced a reduction of serum complement haemolytic activity, leukopenia, thrombocytopenia, a decrease in blood pressure, an increase in haematocrit and paw oedema. Stimulation of platelets resulted in their accumulation in lungs and liver as shown by the distribution of 51Cr-labelled platelets. The hypotensive response to zymosan was largely inhibited by WEB 2086, a PAF antagonist. Plasma extravasation was reduced by WEB 2086, by the association of mepyramine and methysergide with ketoprofen or BW 755C. Paw oedema was increased by ketoprofen and abolished by the association of WEB 2086, BW 755C, methysergide and mepyramine. This treatment did not modify the leukopenia. Lipopolysaccharide produced a decrease in blood pressure and, at higher doses, a reduction of serum complement haemolytic activity. It is concluded that the vascular responses to intravascular complement activation by zymosan in rats depend mainly on the release of PAF. They are also mediated, for a small part, by eicosanoids and mast cell amines. Though zymosan and endotoxin induced similar PAF-dependent effects, the complement system is not involved in endotoxin shock in rats.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed1985

Graded responses of human neutrophils induced by serum-treated zymosan.

A modified zymosan preparation was used to probe the interaction of particulate stimuli with human neutrophils (PMNs). After extraction with alkali and detergent, the zymosan particles retained their ability to be opsonized in serum and to stimulate PMNs. Serum-treated zymosan (STZ) induced dose-dependent superoxide (O2-) production and membrane potential depolarization in the range of 1 to 10 mg/mL of STZ. The rate and extent of secretion of lysozyme and beta-glucuronidase were also dose-dependent in the range of 1 to 10 mg/mL of STZ. Cytochemical studies using nitroblue tetrazolium, however, showed that 92% of PMNs were stimulated to produce O2- at 0.1 mg/mL of STZ. The dose response of O2- production induced by STZ is therefore due to increasing O2- production by individual PMNs and not to the stimulation of more PMNs to produce O2-. Evidence for O2- production was found only in the area of PMN-zymosan contact, suggesting a mechanism for the graded responses of PMNs treated with particulate stimuli. In order to determine the nature of the dose dependence of depolarization (a measure of PMN activation), PMNs equilibrated with the fluorescent probe 3,3'-dipentyloxacarbocyanine were analyzed by flow cytometry. The results demonstrate that STZ induces a dose-dependent depolarization of the membrane potential of individual PMNs. These results also demonstrate that increasing concentrations of STZ can induce increasing PMN responses even when all of the PMNs have been activated. These results are consistent with the hypothesis that receptor-mediated particulate stimulation of PMNs is a phenomenon that results in graded PMN responses.

Cytoplasmic Granules↗
PubMed1986

[Study of alveolar macrophages stimulated with zymosan in vivo using fluorescent probes].

Zymosan granules injected intravenously (100 mg per kg of body weight) to Wistar rats induced strong stimulation of mononuclear phagocyte system. On day 5 zymosan-induced recruitment of monocyte-like cells with high consuming and bactericidal activity into lung spaces could be observed. Using fluorescent probes, it was discovered that the size of alveolar cell membranes in zymosan-stimulated or non-stimulated animals was similar, while the viscosity of membrane lipids of alveolar macrophages was considerably lower in zymosan-stimulated rats. These variations are suggested to be responsible for antiinflammatory and bactericidal macrophage potentials.

Animals↗
PubMed1985

[Possible zymosan stimulation of the immune response of BALB/c mice to sheep erythrocytes and tumor target cells].

Zymosan and its combinations with cyclophosphamide were tested for their effect on various immune responses. Zymosan alone had only minor effect on the cytotoxicity of lymphocytes to allogeneic and syngeneic tumour cells but significantly stimulated delayed-type hypersensitivity response, rosette formation and plaque forming cell response to sheep red blood cells in normal mice. Zymosan diminished immunosuppressive action of cyclophosphamide on the plaque and rosette formations and nonspecific allogeneic lysis of target cells by lymph node lymphocytes. Delayed-type hypersensitivity skin reaction and syngeneic T-killer cell activity increased significantly after the procedure of combination therapy. Lymphocyte stimulation action by the polysaccharide depended on the injection schedule used. Preliminary injection of zymosan was an optimal condition for enhancement of the cellular immune response.

Animals↗