Corynebacterium Parvum Research Articles

Targets of Nitric Oxide in a Mouse Model of Liver Inflammation by Corynebacterium parvum

Treatment of mice with Corynebacterium parvum induces chronic inflammation. This treatment followed by an injection of lipopolysaccharide (LPS) produces hepatic necrosis and death. We examined liver tissue by using electron paramagnetic resonance (EPR) spectroscopy and found that, in addition to the previously reported nonheme nitrosyl complexes, heme nitrosyl complexes were also formed. Hemoglobin nitrosyl complexes measured in the whole blood of mice treated with C. parvum were not increased after additional LPS treatment. However, this treatment significantly increased the heme nitrosyl complexes in the liver, whereas the nonheme nitrosyl complex concentration was unaffected. EPR signals from whole blood and liver tissues from mice treated with C. parvum and C. parvum + LPS were inhibited by prolonged treatment with NG-monomethyl-L-arginine (L-NMA). Nitric oxide (.NO) is known to bind to cytochrome P450 heme, and we consistently found a suppression of EPR signals attributable to ferric low-spin cytochrome P450/P420 peaks in the livers of mice treated with C. parvum and C. parvum + LPS. By performing analyses of EPR spectra obtained from hepatocytes exposed to .NO, we were able to unambiguously identify EPR signals attributable to cytochrome P420 and nonheme nitrosyl complexes in the livers of both treatments. Deconvolution of the composite in vivo EPR spectra indicated that hemoglobin nitrosyl complexes contributed weakly in the C. parvum livers, but threefold more in the C. parvum + LPS livers, suggesting that hemorrhage may have occurred. Experiments with L-NMA treatment revealed that this additional .NO production did not correlate with hepatic necrosis and onset of death. Immunoprecipitation of liver cytosols from C. parvum- and (C. parvum + LPS)-treated mice using an antibody against mouse inducible nitric oxide synthase showed that this enzyme was indeed present in the cytosolic fractions and was absent in those from control livers. Our novel detection of cytochrome P420 nitrosyl complex in vivo may be linked to any role of hepatic P450′s functions during liver inflammation.

Use of prostaglandin I2 analog in treatment of massive hepatic necrosis associated with endothelial cell injury and diffuse sinusoidal fibrin deposition.

Endothelial cell damage causes massive hepatic necrosis as a result of fibrin deposition in the hepatic sinusoids. When a stable analog of prostaglandin I2, beraprost sodium, was administered to rats given either dimethylnitrosamine, carbon tetrachloride, or endotoxin following Corynebacterium parvum administration, the hepatic necrosis produced in each was attenuated, but to a greater extent in the dimethylnitrosamine and endotoxin/Corynebacterium parvum models, where fibrin deposition in the hepatic sinusoids occurs, as compared to the carbon tetrachloride model, where such fibrin deposition does not occur. Beraprost sodium reduced the expected increase of portal venous pressure in the endotoxin/Corynebacterium parvum model without affecting plasma thrombin-antithrombin III complex levels. Beraprost sodium also significantly reduced cell killing of both isolated rat hepatocytes and hepatic sinusoidal endothelial cells exposed to tert-butyl hydroperoxide when compared to controls. Beraprost sodium could prove to be a therapeutic candidate for the treatment of hepatic necrosis, particularly in cases associated with fibrin deposition in the hepatic sinusoids because of its fibrin clot-clearing action.

Mechanism for macrophage activation against Corynebacterium parvum--participation of T cells and its lymphokines.

It is well known that Corynebacterium parvum activates macrophages to produce tumor necrosis factor (TNF). It is suspected that the activation of macrophages by C. parvum requires T-cell participation. The purpose of this study was to confirm that T cells participate in the activation of macrophages by C. parvum. TNF production in vitro from the spleen cells of BALB/c(-)+/+ mice was abrogated completely by the pre-treatment of spleen cells with anti-Ia antiserum and complement, indicating that Ia+ cells are the source of TNF. TNF production was not elicited at all in BALB/c-nu/nu mice. However, there was an increase in the number of Ia+ cells as well as an increase in the weight of spleen and liver. Supernatant from a culture of spleen cells stimulated with phytohemagglutinin-P (a PHA-induced lymphokine) made it possible for BALB/c-nu/nu mice to produce TNF, associated with an induction of Lyt-1+ cells and Lyt-2+ cells. However, treatment with the lymphokine did not augment the increases of Ia+ cells or liver and spleen weights. These results suggest that increasing the number of Ia+ cells is not sufficient to bring about TNF production; Ia+ cells must also be stimulated by T cells or T-cell lymphokines in order to produce TNF. These results suggest that T cells play an essential role in the activation of Ia+ cells against C. parvum.

Kupffer Cell Stimulation with Corynebacterium parvum Reduces Some Cytochrome P450-Dependent Activities and Diminishes Acetaminophen and Carbon Tetrachloride-Induced Liver Injury in the Rat

Chemical activation of Kupffer cells in vivo by vitamin A or latex beads is associated with a worsening of hepatic injury induced by the P450-dependent hepatotoxins acetaminophen (ACET) and carbon tetrachloride (CCl4) and by the P450-independent toxin galactosamine (GLN). Immunostimulants such as Corynebacterium parvum (CP) also activate Kupffer cells, but do so while prompting release of soluble mediators which depress microsomal oxidative activities in cultured hepatocytes. Therefore, we sought to characterize the effects of CP on hepatic injury in vivo due to ACET and CCl4 while employing GLN as a control. Hepatic microsomal oxidative activity and glutathione (GSH) disposition were examined since each influences susceptibility to injury from ACET or CCl4. Rats were given CP 28 mg/kg iv 5 days before challenge with hepatotoxicant. Hepatic injury was assessed 24 hr after hepatotoxicant administration by measurement of serum alanine aminotransferase (ALT) activity and review of histological sections. Livers from parallel groups of rats were used to prepare microsomal and cytosolic fractions, to measure tissue GSH, or for perfusion to assess GSH efflux. Significant reductions in injury due to ACET or CCl4 were observed while injury due to GLN was potentiated. Serum ALT levels after ACET were 3000 ± 620 in controls vs 170 ± 45 IU/liter in the CP-treated group and ALT levels after CCl4 were 3100 ± 500 in controls vs 1700 ± 450 IU/liter in the CP-treated group. In contrast, serum ALT levels after GLN were 920 ± 230 in controls vs 1700 ± 370 in the CP-treated group. Patterns of hepatic injury observed on histological sections were those characteristic for each toxin and the severity of injury correlated well with alterations in serum ALT levels for each agent. Hepatic microsomal fractions from rats pretreated with CP showed significantly diminished total cytochrome P450 content as well as reduced activity for two P450IIE1 substrates, p-nitrophenol and 7-ethoxycoumarin. While sinusoidal efflux of GSH increased by 40% in rats pretreated with CP and cytosolic glutathione-S-transferase activity fell slightly, tissue GSH levels were unaffected. These data demonstrate that CP decreases microsomal cytochrome P450 content, reduces biotransformation of two P450IIE1 substrates, and diminishes ACET- and CCl4-induced hepatic injury. In contrast, hepatic injury due to the P450-independent toxin GLN was enhanced. Thus, chemical and immune stimulation of Kupffer cells may result in divergent effects on susceptibility to injury from individual hepatotoxins.

Inhibition of Nitric Oxide Synthesis Enhances the Expression of Inducible Nitric Oxide Synthase mRNA and Protein in a Model of Chronic Liver Inflammation

In septic shock the inhibition of inducible nitric oxide synthase (iNOS) could be of therapeutic value. However, side effects have to be investigated. Therefore we studied the effects of chronic NOS inhibition on the level of iNOS expression in a model of chronic liver inflammation induced by Corynebacterium parvum(C. parvum) which causes sustained iNOS expression in the liver. NOS inhibitors decreased the rise in plasma levels and urinary excretion of nitrite/nitrate by about 50%; however, iNOS mRNA and protein were increased to 200% and 150%, respectively. Thus chronic inhibition of NOS can result in an increase in iNOS mRNA level and protein under conditions when iNOS is expressed. This could result in an overproduction of NO upon removal of the NOS-inhibitor.

Cellular localization of inducible nitric oxide synthase in experimental endotoxic shock in the rat.

1. Endotoxin induces a shock-like syndrome with increased nitric oxide synthesis. To clarify the cellular source of NO in endotoxic shock we used immunohistochemistry and in situ hybridization to localize inducible NO synthase in rats given lipopolysaccharide or Corynebacterium parvum and lipopolysaccharide. Immunohistochemistry was carried out with an antibody raised against a synthetic peptide of mouse macrophage NO synthase. In situ hybridization was performed with 35S-labelled oligonucleotide probes corresponding to cDNA sequences common to mouse macrophage inducible NO synthase and rat vascular smooth inducible NO synthase. Monocytes and macrophages were identified by immunohistochemistry with the mouse monoclonal antibody ED1. 2. After lipopolysaccharide alone, the major site of NO synthase induction was monocytes and macrophages in multiple organs, principally liver and spleen. Bronchial, bile duct, intestinal and bladder epithelium and some hepatocytes also expressed inducible NO synthase. Expression peaked at 5 h and had returned to normal by 12 h except in spleen. 3. After priming with C. parvum, lipopolysaccharide led to a similar distribution of inducible NO synthase as lipopolysaccharide alone, but in addition there was more prominent hepatocyte staining, staining in macrophage granulomas in the liver and inducible NO synthase was present in some endothelial cells in the aorta. 4. These findings provide a direct demonstration of the cellular localization of inducible NO synthase after lipopolysaccharide.

Herpes simplex virus type 1 replication and IL-1β gene expression in mouse peritoneal macrophages activated in vivo by an attenuated Salmonella typhimurium vaccine or Corynebacterium parvum

Activated macrophages (Mφ) from mice given Salmonella typhimurium or Corynebacterium parvum were compared with resident peritoneal macrophages at the molecular level for permissiveness for herpes simplex virus type 1 (HSV-1) replication and for expression of interleukin-1 beta (IL-1β). Peritoneal macrophages were harvested from mice injected 7 days previously with live, avirulent S. typhimurium (Sal-PMφ) or heat-killed C. parvum (CP-PMφ), and infected with HSV-1 in vitro. Both Sal-PMφ and CP-PMφ were activated as evidenced by characteristic changes in an ectoenzyme, by increased permissiveness for infectious virus production and viral cytopathic effect, and by induction of IL-1β mRNA. Analysis at the molecular level revealed that both types of activated Mφ demonstrated increased patterns of HSV-1 immediate-early gene expression and viral DNA replication as compared with resident cells. A novel finding was that viral infection reduced IL-1β mRNA in both types of activated Mβ. This observation has implications for the efficacy of Salmonella vaccines given in proximity to HSV-1 infection and for potential deleterious effects of HSV-1 infection in immunosuppressed patients receiving immunotherapy.

Nitric oxide and prostaglandins interact to prevent hepatic damage during murine endotoxemia.

Nitric oxide (NO) and prostaglandins (PG) both possess the ability to induce vasodilatation and prevent the aggregation of platelets. The synthesis of these substances is increased following in vivo lipopolysaccharide (LPS) infusion, but their function during sepsis is incompletely understood. We studied the role of NO and PG in a murine model of chronic hepatic inflammation (Corynebacterium parvum injection), which is known to progress to sudden hepatic necrosis after LPS injection. NO synthesis, which is induced in hepatocytes by C. parvum treatment and in nonparenchymal cells by LPS treatment, was inhibited using NG-monomethyl-L-arginine (L-NMMA). High-dose aspirin (ASA) was used to block PG synthesis. Treatment with L-NMMA or ASA alone, in the absence of LPS, resulted in no increase in hepatic injury. C. parvum-treated mice that received both L-NMMA and ASA without LPS developed marked hepatic damage as reflected by increased hepatocellular enzyme release (aspartate aminotransferase and L-ornithine carbamoyl-transferase). Marked hepatic damage was seen after LPS administration, and ASA pretreatment alone had no effect on the LPS-induced hepatic injury, whereas L-NMMA markedly increased the hepatic damage. The combination of L-NMMA and ASA after LPS resulted in the greatest hepatocellular enzyme release, characterized histologically by intravascular thrombosis with diffuse infarction and necrosis. Simultaneous treatment with either PGI2 or L-arginine partially prevented this injury. These data demonstrate that NO and PG function synergistically to maintain hepatocellular integrity; thus increased synthesis of these mediators protects the liver from the pathophysiological effects of LPS in this model.

Cell adhesion molecules on vessels during inflammation in the mouse central nervous system

The expression of endothelial cell adhesion molecules (CAMs) in the central nervous system (CNS) of the mouse was examined during an inflammation induced by intracerebral injection of killed Corynebacterium parvum (C. parvum). We showed that injection of killed C. parvum produced an inflammatory cellular infiltrate limited to the injected brain hemispher. However, the upregulation of ICAM-1 and VCAM-1 on brain endothelium occurred starting 2 days after C. parvum injection throughout the entire CNS and was not restricted to vessels surrounded by a cellular infiltrate. In contrast to the systemic upregulation of ICAM-1 and VCAM-1, cerebral vessels located in the center of the cellular infiltrate started to express the MECA-32 antigen, suggesting an altered functional status of the endothelial cells, as this antigen is suppressed during development of the blood-brain barrier (BBB). Binding assays performed on frozen sections of inflamed brains are consistent with an important role for endothelial VCAM-1 in the recruitment of lymphocytes during inflammation in the CNS of the mouse.

LGL-1: a potential triggering molecule on murine NK cells

Natural killer (NK) cells mediate non-major histocompatibility complex-restricted lysis of tumor cells, lymphokine-activated killing (LAK), antibody-dependent cellular cytotoxicity (ADCC), and reverse ADCC (RADCC). LGL-1+ cells identify a major subset (50%) of murine NK cells. Here we demonstrate that monoclonal antibodies (mAbs) to LGL-1 consistently induce interleukin-2-cultured, and Corynebacterium parvum (in vivo)-activated NK cells to induce RADCC. LGL-1 triggering of activated NK cells coincides with enhanced LGL-1 expression. Testing of murine mAbs to epitopes of CD2 only appears to augment RADCC induced by mAb NK-1.1 on fresh NK cells. Immunoprecipitation of the LGL-1 antigen reveals a highly disulfide-linked 40-kDa homodimer subunit that is N-glycosylated. Therefore, LGL-1 may be similar to other recently characterized NK-associated antigens such as NK-1.1, Ly-49, and NKR-PI. We conclude that although LGL-1 is expressed on "resting" NK cells, enhanced surface expression following activation is usually required for it to act as a signaling molecule.

Mesothelial Cell Injury Caused by Pleural Leukocytes from Rats Treated with Intratracheal Instillation of Crocidolite Asbestos or Corynebacterium parvum

The pleural and peritoneal mesothelium is a major target in asbestos exposure where mesothelial cell proliferation, exfoliation, and neoplasia have been reported in workers and experimental animals. The objective of this study was to determine the role of pleural leukocytes in mesothelial cell damage caused by asbestos exposure. We therefore investigated detachment and lysis injury to mesothelial cells in vitro induced by leukocytes lavaged from the pleural space of rats exposed, by intratracheal instillation, to crocidolite asbestos. Our studies revealed that normal pleural leukocytes were composed of macrophages, lymphocytes, eosinophils, and mast cells. This population showed a small but significant recruitment of mast cells and eosinophils 3 to 14 days after instillation of crocidolite asbestos; there were also modestly increased levels of macrophages present 30 days after low doses of asbestos. One day after intratracheal instillation of 5 mg crocidolite asbestos, the pleural leukocytes caused detachment injury to mesothelial cells in vitro. This injury was markedly reduced 3 days after asbestos exposure and was undetectable by Day 14. One month after instillation of asbestos, despite doses of asbestos from 0.5 to 5 mg, pleural leukocytes showed no ability to injure mesothelial cells in vitro. In a parallel study, pleural inflammation was induced by intratracheal instillation of heat-inactivated Corynebacterium parvum. Transient mesothelial cell-detaching injury was again expressed by pleural leukocytes 1 day after C. parvum instillation. This was likely related to an increase in the percentage of neutrophils present on this day. These results show that a single administration of crocidolite asbestos, intratracheally, leads to transient activation of pleural leukocytes in terms of the ability of these cells to detach mesothelial cells from matrix. This finding implies that mesothelial cell proliferation and exfoliation found in individuals exposed to asbestos may result from persistent stimulation of pleural leukocytes caused by the continuous presence of asbestos in the lung.

Chemical pleurodesis for malignant pleural effusions.

To provide information about available agents for chemical pleurodesis. A MEDLINE search (1966 to October 1992) was conducted using the terms malignant pleural effusion and pleurodesis. All articles containing references to patients with recurrent, symptomatic, malignant pleural effusions treated with chemical pleurodesis were selected and reviewed for pleurodesis regimen, number of patients treated, success rate (complete response), and adverse effects. The agents studied included doxycycline, minocycline, tetracycline, bleomycin, cisplatin, doxorubicin, etoposide, fluorouracil, interferon-beta, mitomycin-c, Corynebacterium parvum, methylprednisolone, and talc. Independent extraction by three observers. Studies including a total of 1168 patients with malignant pleural effusions were reviewed for efficacy of the pleurodesis agent and studies including 1140 patients were reviewed for toxicity. Chemical pleurodesis produced a complete response in 752 (64%) of 1168 patients. The success rate of the pleurodesis agents varied from 0% with etoposide to 93% with talc. Corynebacterium parvum, the tetracyclines, and bleomycin had success rates of 76%, 67%, and 54%, respectively. The most commonly reported adverse effects were pain (265 of 1140, 23%) and fever (220 of 1140, 19%). Doxycycline and minocycline, with success rates of 72% and 86%, respectively, appear to be effective tetracycline-replacement agents in the few patients studied. Talc appears to be the most effective and least expensive agent; however, insufflation has the disadvantages of the expense of thoracoscopy and the usual need for general anesthesia. Bleomycin appears to be less effective than talc and the tetracyclines and is substantially more expensive.

Interaction of lung surfactant protein A with alveolar macrophages.

We analyzed the binding mechanism of human recombinant lung surfactant protein A (SP-A) to rat alveolar macrophages using anti-SP-A antiserum and protein A coated onto gold particles. Results were compared with our recent data on binding and uptake of SP-A-coated colloidal gold particles. The rationale for the current approach was to avoid any possible steric effects on SP-A binding to the cell surface. Binding of unlabeled SP-A depends on the presence of calcium ions in the medium and involves a mannose-specific mechanism. Binding is partly inhibited by the collagenase-resistant fragment of SP-A, representing mainly the globular part of SP-A. Taken together, these facts indicate binding of SP-A via the carbohydrate binding site on the globular region of SP-A. On the other hand, a partial inhibition of SP-A binding by fragments of C1q (representing the collagenous region of C1q) indicates a second binding site for SP-A by the collagen-like portion to the C1q receptor of macrophages. We conclude that two different mechanisms are probably involved in SP-A binding to alveolar macrophages. Specificity of the binding was shown with fluorescein-labeled SP-A. Binding was inhibited by an excess of unlabeled SP-A. Binding and uptake of SP-A are seen only with alveolar macrophages and not with other macrophage populations isolated from rat, such as liver macrophages (Kupffer cells), resident peritoneal macrophages, and peritoneal macrophages activated by Corynebacterium parvum. Therefore, binding sites for SP-A occur exclusively on alveolar macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)

Corynebacterium parvum pretreatment reduces some cytochrome P450-dependent activities and protects against acetaminophen and carbon tetrachloride-induced liver injury in the rat

Corynebacterium parvum pretreatment reduces some cytochrome P450-dependent activities and protects against acetaminophen and carbon tetrachloride-induced liver injury in the rat

Nitric Oxide Synthase Expression Is Induced in Hepatocytes in Vivo during Hepatic Inflammation

Nitric oxide (NO ·) is a short-lived biologic mediator produced by the enzyme NO · synthase (NOS) which exists in constitutive and inducible isoforms. Previously, we have shown that hepatocytes express an inducible NOS in vitro following exposure to the combination of lipopolysaccharide and inflammatory cytokines. The purpose of the present study is to characterize the induction of NOS in vivo in rat hepatocytes during chronic hepatic inflammation triggered by Corynebacterium parvum injection and to correlate NO · synthesis with the timing of liver injury. Using Northern blot hybridization, hepatocyte-inducible NOS mRNA was detected 3 days after C. parvum administration and was not found in normal hepatocytes. Hepatocyte NOS activity was significantly increased 3 to 7 days after C. parvum. Plasma concentrations of nitrite and nitrate (NO - 2 + NO - 3), the stable end products of NO · oxidation, increased from a basal concentration of 21.0 ± 2.5 to 2439.6 ± 364.2 μ M 3 days after injection. Urinary excretion of NO - 2 + NO - 3 also increased in a parallel manner. Plasma liver injury enzymes were elevated three to sixfold in vivo at 3 to 5 days following C. parvum and coincided with the period of maximal NO production. The results show that NO · is produced directly by hepatocytes in vivo during hepatic inflammation and suggest a role for NO · in mediating the hepatic response to inflammatory stimuli.

Phagocytosis of antigens by Langerhans cells in vitro.

Dendritic cells (DC) isolated from lymphoid tissues are generally thought to be nonphagocytic in culture. It has therefore been unclear how these cells could acquire particulate antigens such as microorganisms for initiation of primary immune responses. Lymphoid DC derive in part from cells that have migrated from nonlymphoid tissues, such as Langerhans cells (LC) of skin. The ability of LC to internalize a variety of particles was studied by electron, ultraviolet, phase, and differential interference contrast microscopy, and by two-color flow cytometry. Freshly isolated LC in epidermal cell suspensions phagocytosed the yeast cell wall derivative zymosan, intact Saccharomyces cerevisiae, representatives of two genera of Gram-positive bacteria, Corynebacterium parvum and Staphylococcus aureus, as well as 0.5-3.5-microns latex microspheres. During maturation in culture, the phagocytic activity of these cells was markedly reduced. Likewise, freshly isolated splenic DC were more phagocytic than cultured DC for two types of particle examined, zymosan and latex beads. Unlike macrophages, LC did not bind or internalize sheep erythrocytes before or after opsonization with immunoglobulin G or complement, and did not internalize colloidal carbon. The receptors mediating zymosan uptake by LC were examined. For this particle, C57BL/6 LC were considerably more phagocytic than BALB/c LC and exhibited a reproducible increase in phagocytic activity after 6 h of culture followed by a decline, whereas this initial rise did not occur for BALB/c LC. These differential kinetics of uptake were reflected in the pattern of zymosan binding at 4 degrees C, and endocytosis of the soluble tracer fluorescein isothiocyanate-mannose-bovine serum albumin at 37 degrees C. Zymosan uptake by LC from both strains of mice was inhibited in the presence of mannan or beta-glucan, although to different extents, but not by antibodies specific for CR3 (CD11b/CD18). These data indicate that zymosan uptake by LC can be mediated by a mannose/beta-glucan receptor(s) that is differentially expressed in the two strains of mice and that is downregulated during maturation of LC in culture.

Lipopolysaccharide-induced cytokine production and mortality in mice treated with Corynebacterium parvum.

Tumor necrosis factor alpha (TNF-alpha) has been shown to be an important mediator of the lethal effects of endotoxin in several experimental models of septic shock. However, studies with a recombinant human interleukin-1 (IL-1) receptor antagonist protein (IL-1ra) suggest a role for IL-1 as a mediator of septic shock as well. In the present study, we show that mice treated in vivo with Corynebacterium parvum are primed for the production of interferon-gamma (IFN-gamma) and exhibit an enhanced capacity to produce serum IL-1 alpha, TNF-alpha, and IL-6 when challenged intravenously with lipopolysaccharide (LPS). The majority of C. parvum-treated mice die within 24 h of an LPS challenge. Pretreatment with a rat antimouse TNF-alpha monoclonal antibody (mAb) protected 90% of the animals against the lethal endotoxin challenge, while an anti-IFN-gamma mAb gave approximately 75% protection. The anti-IFN-gamma mAb also caused a reduction in LPS-induced serum TNF-alpha and IL-1 alpha. Anti-IL-1 alpha, anti-IL-1 beta, and anti-IL-6 neutralizing mAb did not protect against lethality when administered to mice prior to the LPS challenge. These results indicate that TNF-alpha and IFN-gamma are major mediators of endotoxin shock in C. parvum-treated mice. The results further suggest that the IFN-gamma produced by C. parvum-primed mice in response to an LPS challenge serves as a stimulus for enhanced production of TNF-alpha and IL-1 alpha. These findings are consistent with an increasing body of evidence suggesting a major role for IFN-gamma in lethal endotoxemia.

Adjuvanticity of Dimethyl Dioctadecyl Ammonium Bromide, Complete Freund's Adjuvant and Corynebacterium parvum with Respect to Host Immune Response to Coccidial Antigens

Immune response of chickens to Eimeria was investigated following immunization with coccidial antigens in combination with various immunological adjuvants. The adjuvanticity of dimethyl dioctadecyl ammonium bromide (DDA) was comparable to that of two other adjuvants known to stimulate cell-mediated immunity: complete Freund's adjuvant (CFA) and Corynebacterium parvum. However, DDA is considered less toxic than CFA and appeared to evoke longer-lasting immunity than C. parvum. In general, intramuscular immunization of chickens with merozoite antigens in DDA engendered higher protective immunity than did oral immunization. Immunization of chickens with merozoite antigens in CFA, DDA, or C. parvum engendered serum IgG and biliary secretory IgA (sIgA) antibody responses, as well as coccidial antigen-specific T-cell lymphoproliferation responses. This study presents evidence that DDA acts as an adjuvant for both coccidia antigen-specific antibody and T-cell immunity in the avian system.

Modulation of murine hepatic lipase activity by exogenous and endogenous Kupffer-cell activation

Deficiency of hepatic lipase (HL) may play a role in the lipoprotein abnormalities in chronic inflammatory states which are characterized by reticuloendothelial-system activation and cytokine release. HL triacylglycerol hydrolase activity was measured in heparin perfusates of livers from autoimmune MRL/lpr mice, which spontaneously develop a condition closely resembling human lupus erythematosis and exhibit spontaneous Kupffer-cell activation after 8 weeks of age, as well as from normal mice treated with Corynebacterium parvum or polyinosinic-polycytidylic acid complex [poly(I.C)] to induce Kupffer-cell activation. HL activity in MRL/lpr mice older than 8 weeks was 29.5% (P = 0.002) of that in age-matched control MRL/++ mice. Treatment of normal mice with C. parvum or poly(I.C) resulted in HL activities 18.6% (P = 0.004) and 13.1% (P = 0.007) respectively of untreated controls. Northern-blot hybridization of liver poly(A)+ RNA showed no differences in HL mRNA abundance in MRL/++ mice compared with the MRL/lpr autoimmune strain after 8 weeks of age, or in normal control mice compared with those treated with C. parvum, indicating attenuation of HL activity at the translational or post-translational level. Deficiency of this enzyme may represent one of the mechanisms contributing to the dyslipoproteinaemia of autoimmune disease and chronic infection.

Sinusoidal endothelial cell damage by activated macrophages in rat liver necrosis

Background: Massive hepatic necrosis caused by fibrin deposition in the hepatic sinusoids develops with hepatic macrophage activation in rats given endotoxin after administration of heat-killed Corynebacterium parvum. Targeted cells of such macrophages were investigated. In C. Parvum-treated rats, the pathological appeMethods:arance of liver cells was serially measured in serum following endotoxin administration and compared with the appearance in the perfusate during closed liver perfusion with endotoxin. Results: Serum activities of tumor necrosis factor, purine nucleoside phosphorylase present in both hepatocytes and sinusoidal endothelial cells, and levels of alanine aminotransferase were higher after 30 minutes, 1 hour, and 3 hours, respectively. Pretreatment of rats with gadolinium chloride, an inhibitor of macrophage function, reduced this liver injury. Although alanine aminotransferase activity remained almost unchanged in the liver perfusate, purine nucleoside phosphorylase activity increased. This increase was reduced when rats were pretreated with gadolinium chloride. There was sinusoidal endothelial cell damage around hepatic macrophages in the liver perfused with endotoxin. Conclusions: Activated hepatic macrophages may cause sinusoidal endothelial cell damage leading to hepatocyte necrosis in rats given C. parvum and endotoxin.