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Abstract
Bacteria living as biofilms have been recognised as the ultimate cause of persistent and destructive inflammatory processes. Biofilm formation is a well-organised, genetically-driven process, which is well characterised for numerous bacteria species. In contrast, the host response to bacterial biofilms is less well analysed, and there is the general believe that bacteria in biofilms escape recognition or eradication by the immune defence. In this review the host response to bacterial biofilms is discussed with particular focus on the role of neutrophils because these phagocytic cells are the first to infiltrate areas of bacterial infection, and because neutrophils are equipped with a wide arsenal of bactericidal and toxic entities. I come to the conclusion that bacterial biofilms are not inherently protected against the attack by neutrophils, but that control of biofilm formation is possible depending on a timely and sufficient host response.
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Neospora caninum excreted/secreted antigens trigger CC-chemokine receptor 5-dependent cell migration. Int J Parasitol 2010; 40:797-805. [PMID: 20060395 DOI: 10.1016/j.ijpara.2009.12.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2009] [Revised: 12/04/2009] [Accepted: 12/06/2009] [Indexed: 01/10/2023]
Abstract
Neospora caninum, the causative agent of neosporosis, is an obligate intracellular parasite considered to be a major cause of abortion in cattle throughout the world. Most studies concerning N. caninum have focused on life cycle, seroepidemiology, pathology and vaccination, while data on host-parasite interaction, such as host cell migration, mechanisms of evasion and dissemination of this parasite during the early phase of infection are still poorly understood. Here we show the ability of excreted/secreted antigens from N. caninum (NcESAs) to attract monocytic cells to the site of primary infection in both in vitro and in vivo assays. Molecules from the family of cyclophilins present on the NcESAs were shown to work as chemokine-like proteins and NcESA-induced chemoattraction involved G(i) protein signaling and participation of CC-chemokine receptor 5 (CCR5). Additionally, we demonstrate the ability of NcESAs to enhance the expression of CCR5 on monocytic cells and this increase occurred in parallel with the chemotactic activity of NcESAs by increasing cell migration. These results suggest that during the first days of infection, N. caninum produces molecules capable of inducing monocytic cell migration to the sites of infection, which will consequently enhance initial parasite invasion and proliferation. Altogether, these results help to clarify some key features involved in the process of cell migration and may reveal virulence factors and therapeutic targets to control neosporosis.
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Southgate EL, He RL, Gao JL, Murphy PM, Nanamori M, Ye RD. Identification of formyl peptides from Listeria monocytogenes and Staphylococcus aureus as potent chemoattractants for mouse neutrophils. THE JOURNAL OF IMMUNOLOGY 2008; 181:1429-37. [PMID: 18606697 DOI: 10.4049/jimmunol.181.2.1429] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The prototypic formyl peptide N-formyl-Met-Leu-Phe (fMLF) is a major chemoattractant found in Escherichia coli culture supernatants and a potent agonist at human formyl peptide receptor (FPR) 1. Consistent with this, fMLF induces bactericidal functions in human neutrophils at nanomolar concentrations. However, it is a much less potent agonist for mouse FPR (mFPR) 1 and mouse neutrophils, requiring micromolar concentrations for cell activation. To determine whether other bacteria produce more potent agonists for mFPR1, we examined formyl peptides from Listeria monocytogenes and Staphylococcus aureus for their abilities to activate mouse neutrophils. A pentapeptide (N-formyl-Met-Ile-Val-Ile-Leu (fMIVIL)) from L. monocytogenes and a tetrapeptide (N-formyl-Met-Ile-Phe-Leu (fMIFL)) from S. aureus were found to induce mouse neutrophil chemotaxis at 1-10 nM and superoxide production at 10-100 nM, similar to the potency of fMLF on human neutrophils. Using transfected cell lines expressing mFPR1 and mFPR2, which are major forms of FPRs in mouse neutrophils, we found that mFPR1 is responsible for the high potency of fMIVIL and fMIFL. In comparison, activation of mFPR2 requires micromolar concentrations of the two peptides. Genetic deletion of mfpr1 resulted in abrogation of neutrophil superoxide production and degranulation in response to fMIVIL and fMIFL, further demonstrating that mFPR1 is the primary receptor for detection of these formyl peptides. In conclusion, the formyl peptides from L. monocytogenes and S. aureus are approximately 100-fold more potent than fMLF in activating mouse neutrophils. The ability of mFPR1 to detect bacterially derived formyl peptides indicates that this important host defense mechanism is conserved in mice.
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Affiliation(s)
- Erica L Southgate
- Department of Pharmacology, University of Illinois College of Medicine, Chicago, IL 60612, USA
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4
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Haas PJ, de Haas CJC, Kleibeuker W, Poppelier MJJG, van Kessel KPM, Kruijtzer JAW, Liskamp RMJ, van Strijp JAG. N-terminal residues of the chemotaxis inhibitory protein of Staphylococcus aureus are essential for blocking formylated peptide receptor but not C5a receptor. THE JOURNAL OF IMMUNOLOGY 2004; 173:5704-11. [PMID: 15494522 DOI: 10.4049/jimmunol.173.9.5704] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Staphylococcus aureus excretes a factor that specifically and simultaneously acts on the C5aR and the formylated peptide receptor (FPR). This chemotaxis inhibitory protein of S. aureus (CHIPS) blocks C5a- and fMLP-induced phagocyte activation and chemotaxis. Monoclonal anti-CHIPS Abs inhibit CHIPS activity against one receptor completely without affecting the other receptor, indicating that two distinct sites are responsible for both actions. A CHIPS-derived N-terminal 6 aa peptide is capable of mimicking the anti-FPR properties of CHIPS but has no effect on the C5aR. Synthetic peptides in which the first 6 aa are substituted individually for all other naturally occurring amino acids show that the first and third residue play an important role in blocking the FPR. Using an Escherichia coli expression system, we created mutant CHIPS proteins in which these amino acids are substituted. These mutant proteins have impaired or absent FPR- but still an intact C5aR-blocking activity, indicating that the loss of the FPR-blocking activity is not caused by any structural impairment. This identifies the first and third amino acid, both a phenylalanine, to be essential for CHIPS blocking the fMLP-induced activation of phagocytes. The unique properties of CHIPS to specifically inhibit the FPR with high affinity (kd=35.4 +/- 7.7 nM) could be an important new tool to further stimulate the fundamental research on the mechanisms underlying the FPR and its role in disease processes.
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MESH Headings
- Amino Acid Sequence
- Amino Acid Substitution/genetics
- Amino Acid Substitution/immunology
- Animals
- Antibodies, Blocking/chemistry
- Antibodies, Blocking/metabolism
- Antibodies, Monoclonal/chemistry
- Antibodies, Monoclonal/metabolism
- Bacterial Proteins/antagonists & inhibitors
- Bacterial Proteins/chemistry
- Bacterial Proteins/genetics
- Bacterial Proteins/immunology
- Bacterial Proteins/metabolism
- Binding Sites, Antibody
- Binding, Competitive/genetics
- Binding, Competitive/immunology
- Cell Migration Inhibition
- Female
- Humans
- Iodine Radioisotopes/metabolism
- Mice
- Mice, Inbred BALB C
- Molecular Sequence Data
- Peptide Fragments/chemistry
- Peptide Fragments/genetics
- Peptide Fragments/immunology
- Peptide Fragments/metabolism
- Receptor, Anaphylatoxin C5a/antagonists & inhibitors
- Receptor, Anaphylatoxin C5a/metabolism
- Receptors, Formyl Peptide/antagonists & inhibitors
- Receptors, Formyl Peptide/metabolism
- Staphylococcus aureus/immunology
- U937 Cells
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Affiliation(s)
- Pieter-Jan Haas
- Eijkman Winkler Laboratory, University Medical Center Utrecht, Utrecht, The Netherlands.
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5
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Fu H, Dahlgren C, Bylund J. Subinhibitory concentrations of the deformylase inhibitor actinonin increase bacterial release of neutrophil-activating peptides: a new approach to antimicrobial chemotherapy. Antimicrob Agents Chemother 2003; 47:2545-50. [PMID: 12878517 PMCID: PMC166101 DOI: 10.1128/aac.47.8.2545-2550.2003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2002] [Revised: 03/10/2003] [Accepted: 05/24/2003] [Indexed: 11/20/2022] Open
Abstract
Bacterial protein synthesis starts with a formylated methionine residue, and this residue is sequentially cleaved away by a unique peptide deformylase (PDF) and a methionine aminopeptidase to generate mature proteins. The formylation-deformylation of proteins is a unique hallmark of bacterial metabolism and has recently become an attractive target for the development of antimicrobial agents. The innate immune system uses the formylation of bacterial proteins as a target, and professional phagocytes, e.g., neutrophils, express specific receptors for bacterium-derived formylated peptides. Activation of formyl peptide receptors (FPR) mediates neutrophil migration and the release of oxygen radicals and other antimicrobial substances from these cells. We hypothesize that the use of a PDF inhibitor would increase the production of proinflammatory peptides from the bacteria and thus trigger a more pronounced innate immune response. We tested this hypothesis by exposing Escherichia coli to subinhibitory doses of the PDF inhibitor actinonin and show that actinonin indeed increases the production and secretion of neutrophil-activating peptides that activate human neutrophils through FPR. These findings could be potentially used as a new approach to antibacterial chemotherapy.
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Affiliation(s)
- Huamei Fu
- The Phagocyte Research Laboratory, Department for Rheumatology and Inflammation Research, University of Göteborg, Göteborg, Sweden.
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6
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Rao SP, Hayashi T, Catanzaro A. Identification of a chemotactic, MCP-1-like protein from Mycobacterium avium. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 2002; 33:115-24. [PMID: 12052566 DOI: 10.1111/j.1574-695x.2002.tb00580.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the immunocompetent host, Mycobacterium avium is responsible for chronic localized pulmonary disease, which is characterized by the presence of increased numbers of activated T cells and macrophages in the lungs. M. avium organisms as well as sonic extracts of M. avium were found to act as chemoattractants for THP-1 cells as well as monocytes, monocyte-derived macrophages and alveolar macrophages obtained from normal human donors in an in vitro chemotaxis assay, where a significantly higher number of cells were found in wells containing M. avium compared to control wells. Proteolytic treatment of M. avium sonicate resulted in significant loss (50%) of chemotactic activity. Monoclonal antibodies against recombinant human monocyte chemoattractant protein-1 (MCP-1) were found to cross-react with a 34-kDa protein of M. avium sonicate on Western blot and inhibit M. avium sonicate-mediated chemotaxis of THP-1 cells (47%). These data suggest the presence of an 'MCP-1 like' molecule on M. avium. Recruitment of host immune regulatory cells to the site of infection by pathogens may be involved in generating a local immune response or may be a bacterial strategy for survival within the host by recruiting the cells that they infect, i.e. macrophages.
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Affiliation(s)
- Savita P Rao
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of California San Diego, 200, W. Arbor Drive, San Diego, CA 92103-8374, USA.
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7
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Affiliation(s)
- J M Schröder
- Department of Dermatology, University of Kiel, Kiel, Germany
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8
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Gao JL, Chen H, Filie JD, Kozak CA, Murphy PM. Differential expansion of the N-formylpeptide receptor gene cluster in human and mouse. Genomics 1998; 51:270-6. [PMID: 9722950 DOI: 10.1006/geno.1998.5376] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The human formylpeptide receptor (FPR) gene cluster has three members: FPR1 and FPRL1, which are expressed in neutrophils and monocytes and encode seven-transmembrane-domain chemotactic receptors specific for N-formylpeptides, and FPRL2, whose function is unknown. The FPRL1 receptor is also a lipoxin A4 receptor. Using probes for the three human genes we have cloned six distinct mouse genes, designated Fpr1 and Fpr-rs1 through Fpr-rs5, which form a cluster on chromosome 17 in a region of conserved synteny with human chromosome 19. Fpr1 encodes a functional receptor and is clearly the orthologue of FPR1. Both Fpr-rs1 and Fpr-rs2 have higher sequence homology to FPRL1 than to FPRL2; Fpr-rs1 is 97% identical in amino acid sequence to a previously reported cDNA that encodes a lipoxin A4 receptor, whereas the putative ligand for Fpr-rs2 is unknown. Fpr-rs3, Fpr-rs4, and Fpr-rs5 appear to lack human counterparts and are most similar in sequence to FPRL1. RNA for Fpr1, Fpr-rs1, and Fpr-rs2 is present in leukocytes, spleen, and lung, whereas RNA for Fpr-rs3 was detected only in skeletal muscle. We did not detect Fpr-rs4 or Fpr-rs5 RNA in any tissue tested. Moreover, Fpr-rs5 has a stop codon in the protein-coding region corresponding to transmembrane domain VI and may not encode a functional receptor. These results suggest that the FPR gene cluster has undergone differential expansion in mammals with FPRL2, Fpr-rs2, Fpr-rs3, Fpr-rs4, and Fpr-rs5 arising after divergence of human and mouse.
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Affiliation(s)
- J L Gao
- Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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9
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Thakur A, Willcox MD. Chemotactic activity of tears and bacteria isolated during adverse responses. Exp Eye Res 1998; 66:129-37. [PMID: 9533839 DOI: 10.1006/exer.1997.0409] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Inflammatory processes are characterized by the dynamic influx of leukocytes. This leukocyte recruitment and activation is thought to be initiated by chemical signals including chemotactic factors. This study was designed to investigate the chemotactic activity in different tear types and bacteria isolated during adverse responses to contact lens wear. Chemotactic activity was determined by quantitating in vitro neutrophil migration using a microchemotaxis chamber. Results demonstrated that tears collected immediately after 8 hours sleep (P<0.001) and tears collected during adverse responses (P<0.001) showed significantly higher chemotactic activity compared to reflex tears. Specific neutralizing antibodies to IL-8, LTB4 and C5a were added to closed eye and adverse response tears. Pre-incubation of closed eye tears with antibodies to IL-8 showed a significant reduction in chemotactic activity (P<0.0001), whereas a significant reduction of PMN migration in adverse response tears was observed after pre-treatment with antibodies to LTB4 (P<0.0001). However no difference in chemotactic activity was observed after incubation with antibody to C5a or irrelevant antibody. Dot blots demonstrated that closed eye tears contained approximately 150 ng ml-1 IL-8 and adverse response tears contained 2 ng ml-1 IL-8. Most Gram negative bacteria isolated from contact lenses caused directed migration of PMNs. Addition of neutralizing antibody to LPS significantly abrogated the chemotactic activity of bacterial cells (P<0.001). Our findings provide evidence that IL-8 during eye closure, and bacterial chemotactic substances and LTB4 during contact lens induced adverse responses, are responsible for the recruitment of PMNs.
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Affiliation(s)
- A Thakur
- Cooperative Research Centre for Eye Research and Technology, The University of New South Wales, Sydney, NSW, 2052, Australia
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10
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Kahlke B, Brasch J, Christophers E, Schröder JM. Dermatophytes contain a novel lipid-like leukocyte activator. J Invest Dermatol 1996; 107:108-12. [PMID: 8752848 DOI: 10.1111/1523-1747.ep12298332] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In the early phase of dermatophytosis, neutrophils are regularly detected microscopically in the infected skin. Although neutrophil recruitment may at least in part occur indirectly by complement activation, we asked whether dermatophytes might release chemoattractants for neutrophils. We cultivated various strains of different dermatophytes and tested fungal extracts for the presence of neutrophil chemotactic activity. As a result, we detected neutrophil chemotactic activity only in diethylether extracts, but not in aqueous extracts. We purified this lipid-like leukocyte activator (LILA) to apparent homogeneity by reversed-phase high performance liquid chromatography and found that purified LILA does not show ultraviolet absorption at wavelengths > 210 nm. Biologic studies revealed that LILA is as effective as formyl-methionyl-leucyl-phenylalanine in eliciting neutrophil chemotaxis, degranulation, and activation of the respiratory burst. Desensitization experiments in chemotaxis and degranulation with leukotriene B4, platelet-activating factor, or 5-oxo-eicosanoids revealed that LILA does not cross-desensitize with any of these other lipid-like attractants and thus possibly acts via a distinct as yet postulated neutrophil receptor. It is hypothesized that LILA, similarly to formylated methionyl peptides in bacteria, represents a dermatophyte- and possibly fungus-specific lipid compound that allows the host phagocytes to specifically recognize fungal infection. This system would be similar to the recognition of bacteria by phagocytes via N-formylated methionyl peptides, which represent a characteristic and unique system to identify bacteria.
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Affiliation(s)
- B Kahlke
- Clinical Research Unit "Cutaneous Inflammation," Department of Dermatology, University of Kiel, Germany
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11
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Karlsson A, Markfjäll M, Strömberg N, Dahlgren C. Escherichia coli-induced activation of neutrophil NADPH-oxidase: lipopolysaccharide and formylated peptides act synergistically to induce release of reactive oxygen metabolites. Infect Immun 1995; 63:4606-12. [PMID: 7591113 PMCID: PMC173662 DOI: 10.1128/iai.63.12.4606-4612.1995] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The prevailing view of neutrophil NADPH-oxidase activation during interaction with bacteria is that the production of toxic oxygen metabolites should be directed into the phagosome containing the engulfed prey. However, in this report we show that a common Escherichia coli strain, HB101, may induce a release of neutrophil oxygen metabolites to the extracellular milieu. This phenomenon is dependent on three factors: (i) the mobilization (upregulation) of neutrophil secretory vesicles prior to interaction with the bacteria, (ii) soluble bacterial factors binding to the formylmethionyl-leucyl-phenylalanine receptor and tentatively identified as formylated peptides, and (iii) a bacterium-associated priming factor identified as lipopolysaccharide.
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Affiliation(s)
- A Karlsson
- Department of Medical Microbiology and Immunology, Faculty of Odontology, University of Göteborg, Sweden
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12
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Abstract
Enterococci are commensal organisms well suited to survival in intestinal and vaginal tracts and the oral cavity. However, as for most bacteria described as causing human disease, enterococci also possess properties that can be ascribed roles in pathogenesis. The natural ability of enterococci to readily acquire, accumulate, and share extrachromosomal elements encoding virulence traits or antibiotic resistance genes lends advantages to their survival under unusual environmental stresses and in part explains their increasing importance as nosocomial pathogens. This review discusses the current understanding of enterococcal virulence relating to (i) adherence to host tissues, (ii) invasion and abscess formation, (iii) factors potentially relevant to modulation of host inflammatory responses, and (iv) potentially toxic secreted products. Aggregation substance, surface carbohydrates, or fibronectin-binding moieties may facilitate adherence to host tissues. Enterococcus faecalis appears to have the capacity to translocate across intact intestinal mucosa in models of antibiotic-induced superinfection. Extracellular toxins such as cytolysin can induce tissue damage as shown in an endophthalmitis model, increase mortality in combination with aggregation substance in an endocarditis model, and cause systemic toxicity in a murine peritonitis model. Finally, lipoteichoic acid, superoxide production, or pheromones and corresponding peptide inhibitors each may modulate local inflammatory reactions.
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Affiliation(s)
- B D Jett
- Division of Laboratory Medicine, Washington University Medical Center, St. Louis, Missouri 63110
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13
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A structural homologue of the N-formyl peptide receptor. Characterization and chromosome mapping of a peptide chemoattractant receptor family. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)42563-x] [Citation(s) in RCA: 147] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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14
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Mai UE, Perez-Perez GI, Allen JB, Wahl SM, Blaser MJ, Smith PD. Surface proteins from Helicobacter pylori exhibit chemotactic activity for human leukocytes and are present in gastric mucosa. J Exp Med 1992; 175:517-25. [PMID: 1732414 PMCID: PMC2119134 DOI: 10.1084/jem.175.2.517] [Citation(s) in RCA: 267] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The mechanism by which Helicobacter pylori, a noninvasive bacterium, initiates chronic antral gastritis in humans is unknown. We now show that H. pylori releases products with chemotactic activity for monocytes and neutrophils. This chemotactic activity was inhibited by antisera to either H. pylori whole bacteria or H. pylori-derived urease. Moreover, surface proteins extracted from H. pylori and purified H. pylori urease (a major component of the surface proteins) exhibited dose-dependent, antibody-inhibitable chemotactic activity. In addition, a synthetic 20-amino acid peptide from the NH2-terminal portion of the 61-kD subunit, but not the 30-kD subunit, of urease exhibited chemotactic activity for monocytes and neutrophils, localizing the chemotactic activity, at least in part, to the NH2 terminus of the 61-kD subunit of urease. The ability of leukocytes to chemotax to H. pylori surface proteins despite formyl-methionyl-leucyl-phenylalanine (FMLP) receptor saturation, selective inhibition of FMLP-mediated chemotaxis, or preincubation of the surface proteins with antiserum to FMLP indicated that the chemotaxis was not FMLP mediated. Finally, we identified H. pylori surface proteins and urease in the lamina propria of gastric antra from patients with H. pylori-associated gastritis but not from uninfected subjects. These findings suggest that H. pylori gastritis is initiated by mucosal absorption of urease, which expresses chemotactic activity for leukocytes by a mechanism not involving N-formylated oligopeptides.
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Affiliation(s)
- U E Mai
- Cellular Immunology Section, National Institute of Dental Research, National Institutes of Health, Bethesda, Maryland 20892
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15
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Mooney C, Keenan J, Munster D, Wilson I, Allardyce R, Bagshaw P, Chapman B, Chadwick V. Neutrophil activation by Helicobacter pylori. Gut 1991; 32:853-7. [PMID: 1885065 PMCID: PMC1378951 DOI: 10.1136/gut.32.8.853] [Citation(s) in RCA: 112] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Helicobacter pylori infection of the stomach is accompanied by a persistent polymorphonuclear leukocyte (PMNL) infiltrate of the mucosa. The aim of this work was to study the activation of human PMNL by substances produced by H pylori. Filtered H pylori conditioned media stimulated a significant PMNL oxidative burst (p less than 0.002). This was equal to 26% of the maximal response stimulated by the PMNL chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP, 1 mumol/l). The response to FMLP was prolonged by the combined presence of complement inactivated human anti-H pylori plasma and conditioned medium (p less than 0.002). High pressure liquid chromatography of an extract of conditioned medium showed a fraction that stimulated PMNL, eluted, and antigenically cross reacted with FMLP. Washed H pylori cells, and those opsonised with complement inactivated human anti-H pylori plasma, did not induce a significant oxidative burst. Opsonized H pylori, however, prolonged the oxidative burst induced by FMLP (p less than 0.02). In conclusion, H pylori synthesizes and secretes a substance, probably FMLP, that may account for the PMNL accumulation that accompanies H pylori infections. Immune complexes composed of H pylori antigen and specific antibody potentiate the PMNL oxidative burst. This combination of H pylori derived products, and host PMNL and antibodies, may be involved in the mucosal damage observed in H pylori associated gastritis.
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Affiliation(s)
- C Mooney
- University Department of Surgery, Christchurch School of Medicine, New Zealand
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16
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Abstract
Polymorphonuclear leukocytes (neutrophils) are recruited to inflammatory sites by a variety of soluble mediators (chemoattractants) that stimulate neutrophil directed migration (chemotaxis). Many neutrophil chemoattractants such as neutrophil activating proteins, leukotriene B4 (LTB4), platelet activating factor, and complement-derived C5a, are generated endogenously by host cells or enzymatic cleavage of host proteins. Other chemoattractants such as N-formyl peptides are generated exogenously by bacteria that invade the host. Oxidative modification of methionine residues or changes in the amino acid sequence of peptide chemoattractants dramatically alter their chemoattractive properties. Many of the well-defined neutrophil chemotactic factors and studies of their structure-function relationships will be reviewed.
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Affiliation(s)
- L Harvath
- Division of Hematology, Food and Drug Administration, Bethesda, MD 20892
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17
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Sannomiya P, Craig RA, Clewell DB, Suzuki A, Fujino M, Till GO, Marasco WA. Characterization of a class of nonformylated Enterococcus faecalis-derived neutrophil chemotactic peptides: the sex pheromones. Proc Natl Acad Sci U S A 1990; 87:66-70. [PMID: 2104986 PMCID: PMC53200 DOI: 10.1073/pnas.87.1.66] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Bacteria produce a heterogeneous mixture of neutrophil chemotactic agents in culture filtrates. Formylmethionyl peptides have been shown to comprise a significant portion of the chemotactic activity in bacterial culture filtrates; however, not all of the chemotactic agents in bacterial culture filtrates are formylated peptides. To examine whether nonformylated peptides derived from bacteria could act as chemotactic agents, we studied several nonformylated hepta- and octapeptide Enterococcus faecalis-derived sex pheromones, their modified derivatives, and their competitive inhibitors for activation of rat peritoneal neutrophils. Several of these peptides, in particular cAM373 and cPD1, proved to be potent chemotactic agents in submicromolar concentrations as well as inducers of lysosomal granule enzyme secretion. Moreover, the more biologically active peptides were able to compete with fMet-Leu-[3H]Phe for binding to the formyl peptide receptor. These studies demonstrate that the formylmethionyl moiety may be an absolute requirement only for the binding of di- and tripeptides to the formyl peptide receptor. Larger peptides that may have or that may allow for additional contact points between the peptide and receptor may require N-formylation only relatively. Indeed, by removing this structural restraint, the formyl peptide receptor may interact with an unlimited number of peptide fragments of both infectious and host origins to then modulate neutrophil responses to infection and inflammation.
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Affiliation(s)
- P Sannomiya
- Instituto de Ciencas Biomédicas, Universidade de Sào Paulo, Brazil
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18
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Gierschik P, Steisslinger M, Sidiropoulos D, Herrmann E, Jakobs KH. Dual Mg2+ control of formyl-peptide-receptor--G-protein interaction in HL 60 cells. Evidence that the low-agonist-affinity receptor interacts with and activates the G-protein. EUROPEAN JOURNAL OF BIOCHEMISTRY 1989; 183:97-105. [PMID: 2502402 DOI: 10.1111/j.1432-1033.1989.tb14901.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In neutrophils and several other phagocytic cell types, a pertussis- and cholera-toxin-sensitive form of the guanine-nucleotide-binding protein (G-protein) Gp couples receptors for N-formylmethionine-containing chemotactic peptides to stimulation of phospholipase C. Using membranes of myeloid differentiated HL 60 cells, we have examined the role of Mg2+ and guanine nucleotides in regulating (a) the interaction of the formyl-peptide receptor with the chemotactic agonist N-formylmethionyl-leucyl-phenylalanine (fMet-Leu-Phe) and (b) the receptor-mediated activation of Gp. Mg2+ markedly enhanced the number of receptors with high affinity for the radiolabeled oligopeptide fMet-Leu-[3H]Phe. At the same time, Mg2+ largely increased the potency of guanosine-5'-(3-O-thio)triphosphate, but not of GDP or guanosine-5'-(2-O-thio)diphosphate, to inhibit binding of the peptide. Comparison of the potency of Mg2+ in eliciting these two effects and analysis of the specificities of the relevant divalent cation sites revealed that Mg2+ interacts with at least two independent sites on the receptor-Gp complex. One site is specific for Mg2+ and exhibits affinity in the micromolar range, the other site interacts with millimolar concentrations of several divalent cations in a non-selective fashion. It is suggested that the former site is located on Gp and that interaction of Mg2+ with this site is necessary for the receptor-mediated G-protein activation, whereas interaction of divalent cations with the latter site is necessary for high affinity agonist binding. The regulation of the formyl-peptide receptor binding properties by guanine nucleotides is independent of Gp activation, since inhibition of peptide binding is achieved by addition of both guanine nucleoside diphosphates and triphosphates and is readily seen both in the presence and in the absence of Mg2+. The latter finding, together with the observation that, at micromolar concentrations of Mg2+, high-affinity GTPase activity is stimulated by fMet-Leu-Phe primarily via low affinity receptors, suggests that, contrary to widely held opinions, (a) divalent cations are not required for a functional receptor--G-protein interaction and (b) high-affinity agonist binding is not a prerequisite for the receptor-mediated activation of the G-protein.
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Affiliation(s)
- P Gierschik
- Pharmakologisches Institut, Universität Heidelberg, Federal Republic of Germany
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Terui T, Rokugo M, Kato T, Tagami H. Analysis of the proinflammatory property of epidermal cyst contents: chemotactic C5a anaphylatoxin generation. Arch Dermatol Res 1989; 281:31-4. [PMID: 2786384 DOI: 10.1007/bf00424269] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We investigated in vitro the contents of epidermal cysts for complement activation and found that they activated complement mainly through the alternative pathway. Chemotactic C5a anaphylatoxin produced by the cyst contents after contact with serum most likely plays a significant role in the initiation and aggravation of inflammation in ruptured epidermal cysts. Our additional study disclosed that components of three representative follicular resident microorganisms (Pityrosporum ovale, Propionibacterium acnes, and Staphylococcus epidermidis) also produced C5a anaphylatoxin mainly through the alternative pathway; the C5a production was more vigorous than that by a virulent pathogen, Staphylococcus aureus. These results suggest that accidental colonization of the cyst contents by these follicular microbial flora further augments the inflammatory changes in ruptured epidermal cysts.
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Affiliation(s)
- T Terui
- Department of Dermatology, Tohoku University School of Medicine, Sendai, Japan
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Blancquaert AM, Colgan SP, Bruyninckx WJ. Chemotactic and chemokinetic activity of Streptococcus faecalis culture supernatant for equine neutrophils. Vet Immunol Immunopathol 1988; 19:285-97. [PMID: 3150886 DOI: 10.1016/0165-2427(88)90115-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Although equine neutrophils did not respond towards formylated methionyl peptides, Streptococcus faecalis culture supernatant caused an in vitro stimulation of equine neutrophil motility when measured by an under-agarose assay. The migration of neutrophils towards the culture supernatant increased sigmoidally with the logarithmic concentration of the culture supernatant in the chemoattractant wells. The streptococcal culture supernatant was chemokinetic because it stimulated the random motility of the phagocytes. Because granulocytes migrated further towards the supernatant than could be explained by the chemokinetic activity of the bacterial products, the streptococcal culture fluid also exerted a chemotactic effect on the leukocytes. The chemotactic activity of the supernatant was further confirmed by the changes in the orientation of the migrating cells during incubation. These results indicate that bacteria produce cytotaxins other than formylmethionyl peptides which are recognized by equine neutrophils.
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Affiliation(s)
- A M Blancquaert
- Department of Microbiology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins
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Ferguson MM, Mellor DM, Morris K, Chadwick VS. Bacterial chemotactic peptide-degrading enzymes in human saliva. J Periodontal Res 1988; 23:245-7. [PMID: 2972820 DOI: 10.1111/j.1600-0765.1988.tb01366.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Nast CC, LeDuc LE. Chemotactic peptides. Mechanisms, functions, and possible role in inflammatory bowel disease. Dig Dis Sci 1988; 33:50S-57S. [PMID: 3278869 DOI: 10.1007/bf01538131] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
An important component of host defenses is the ability of inflammatory cells to detect and respond to minute concentrations of chemoattractant substances. Chemotactic peptides elaborated by both bacteria and leukocytes are the focus of this review. These peptides induce directed migration of inflammatory cells towards their targets, and stimulate biological functions including degranulation, release of oxygen radicals, phagocytosis, and eicosanoid production. Among the released eicosanoids, leukotriene B4 potentiates the leukocyte response. As with other chemotactic factors, these functions are regulated partially through differential coupling to high- and low-affinity receptors and via calcium as the second messenger. Some chemotactic peptides are elaborated by normal colonic luminal bacteria. Recent evidence demonstrates that these peptides can produce mucosal inflammation in vivo. A possible mechanism for this effect involves abnormal colonic permeability in susceptible individuals that allows bacterial chemotactic peptides access to the mucosa where they may induce inflammation. Remaining questions include the mechanism by which the mucosal barrier is breached and the role of leukotrienes in the potentiation of colonic inflammation.
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Affiliation(s)
- C C Nast
- Department of Pathology, Harbor-UCLA Medical Center, Torrance 90509
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Chadwick VS, Mellor DM, Myers DB, Selden AC, Keshavarzian A, Broom MF, Hobson CH. Production of peptides inducing chemotaxis and lysosomal enzyme release in human neutrophils by intestinal bacteria in vitro and in vivo. Scand J Gastroenterol 1988; 23:121-8. [PMID: 3278364 DOI: 10.3109/00365528809093861] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Low molecular weight (Mr 200-1500) N-formylated peptides that stimulate many leucocyte functions, including chemotaxis and lysosomal enzyme release, have previously been isolated from Escherichia coli cultures. We have used high-performance liquid chromatography and bioassay techniques to study production of such peptides by intestinal bacteria in vitro and their activity in intestinal luminal contents, obtained by in vivo dialysis methods. Bioactivity was detected in culture supernatants of all 11 species of bacteria so far investigated, was resistant to digestion with aminopeptidase, but was destroyed by carboxypeptidase, confirming that bioactive moieties were amino-terminal-blocked peptides. By similar isolation procedures, pronase-sensitive bioactive factors have been demonstrated in human rectal dialysates from normal subjects and patients with Crohn's disease. In the patients, bioactivity in dialysates was not observed after treatment with broad-spectrum poorly absorbed antibiotics. The gut may be a reservoir or source of bacterial peptides that could promote an inflammatory response should they cross the 'mucosal barrier'.
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Affiliation(s)
- V S Chadwick
- Wellcome Medical Research Institute, University of Otago Medical School, Dunedin, New Zealand
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Rot A, Henderson LE, Copeland TD, Leonard EJ. A series of six ligands for the human formyl peptide receptor: tetrapeptides with high chemotactic potency and efficacy. Proc Natl Acad Sci U S A 1987; 84:7967-71. [PMID: 2825171 PMCID: PMC299457 DOI: 10.1073/pnas.84.22.7967] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We recently isolated, from culture fluids of Staphylococcus aureus, a chemotactic peptide that comprised equimolar quantities of methionine, leucine, phenylalanine, and isoleucine. It interacted with the formylmethionyl peptide receptor of human leukocytes and had considerably higher potency and efficacy than the widely studied tripeptide agonist fMet-Leu-Phe. On the assumption that the attractant was a formylmethionyl tetrapeptide, we synthesized the six possible sequences and tested the products for chemotactic potency and efficacy, as well as their capacity to inhibit binding of fluorescein isothiocyanate-labeled fMet-Leu-Phe-Lys to human monocytes. The concentrations required for inhibition of fluorescein-labeled fMet-Leu-Phe-Lys binding by the six peptides covered three orders of magnitude. Chemotactic potency (concentration that caused 50% of the maximum chemotactic response) ranged from 3.1 X 10(-11) M to 6.4 X 10(-10) M; efficacy (percentage of monocytes migrating at optimal attractant concentration) ranged from 41% to 66%. When the six synthetic tetrapeptides were ranked for chemotactic efficacy, they paired according to the position of phenylalanine. The average percentage migration was 66% for the two peptides with phenylalanine in position 3, 51% for phenylalanine in position 4, and 41% for phenylalanine in position 2. Since the published value for the percentage of human monocytes with detectable formyl peptide receptors is 60%, it is apparent that the two tetrapeptides with phenylalanine in position 3 (fMet-Ile-Phe-Leu and fMet-Leu-Phe-Ile) are full chemotactic agonists, which are capable of inducing migration of all the receptor-bearing cells. This is in contrast to the tripeptide fMet-Leu-Phe, which induces migration of only 50% of monocytes with receptors (efficacy of 33%). Since the chemotactic efficacy of the six tetrapeptides covers a wide range, the series may be useful to investigate signals that lead to directed movement after occupancy of receptors by chemoattractants.
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Affiliation(s)
- A Rot
- Immunopathology Section, National Cancer Institute, Frederick, MD
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Abstract
Leukocyte chemoattractants markedly alter the morphology and membrane functions of leukocytes. Bacterial collagenase causes a change in cell shape similar to that seen with the leukocyte chemoattractant, f-Met-Leu-Phe, and also promotes capping of concanavalin A. Human neutrophils in suspension or adherent to cover glasses were exposed to clostridial collagenase (10-250 units/ml) for up to 30 min at 37 degrees C and then fixed. Collagenase (125 units/ml) caused more than 85% of PMNs to assume an asymmetric or motile morphology even in the presence of 1% gelatin or 10 mg/ml bovine serum albumin. Trypsin alone (0.01-1%) did not induce a shape change. A similar morphology was seen in some untreated PMNs (less than 5% of all cells) and is characteristic of f-Met-Leu-Phe-treated cells (more than 90%). Collagenase inhibitors (i.e., reduced glutathione, cysteine, and acid-soluble collagen), however, prevented the shape change induced by collagenase but not by f-Met-Leu-Phe. At 4 degrees C, fluorescein-Con A (20 micrograms/ml) bound uniformly to both untreated and collagenase-treated cells. Upon further incubation at 37 degrees C, Con A was internalized over the entire cell periphery of the rounded, untreated cells but on collagenase-treated PMNs was rapidly gathered into a cap overlying the uropod or protuberant region of cytoplasm where it was subsequently internalized. Checkerboard Boyden chamber assays showed clostridial collagenase to be chemokinetic and chemotactic for human PMNs. In receptor binding experiments, the clostridial collagenase preparation competed poorly with [125I]formylhexapeptide for binding to PMN formylpeptide receptors (less than 15% reduction in binding at 200 units/ml collagenase). Thus, collagenase does not seem to interact strongly with the neutrophil formylpeptide receptor and may stimulate PMN motility by interacting at an altogether different site.
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Abstract
Phagocytosis is an important factor in the defense of the host against all kinds of microorganisms. The process of phagocytosis of microorganisms by phagocytes can be separated into distinct but interrelated phases: adherence, chemotaxis, opsonization, attachment, ingestion, degranulation and killing. Phagocytosis is accompanied by an increase in oxygen metabolism in which H2O2 and activated oxygen species are generated. Modulation of phagocytic cell function can be brought about by a variety of substances. Microorganisms produce and contain components which influence the process of phagocytosis. Surrounding tissue cells and the phagocytes themselves produce biologically active molecules that modulate phagocytosis.
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Lareau DE, Herzberg MC, Nelson RD. Human neutrophil migration under agarose to bacteria associated with the development of gingivitis. J Periodontol 1984; 55:540-9. [PMID: 6592328 DOI: 10.1902/jop.1984.55.9.540] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
In clinically healthy gingiva and increasingly with the development of inflammation, neutrophils are found in the gingival tissues and sulcus. This study evaluated the relative ability of bacteria associated with gingival health and developing inflammation to stimulate this increase in neutrophil accumulation. Dialyzed bacterial sonic extracts (BE) in buffer and pooled human serum (PHS) from pure cultures of Streptococcus sanguis. Actinomyces viscosus, A naeslundii, Bacteroides intermedius, Fusobacterium sp and Veillonella sp were tested for stimulation of human neutrophil migration under agarose. In addition, fractions of S sanguis culture fluids (CFs) from Sephadex G-10 chromatography were evaluated. All BE solutions were incubated for 1 hour at 37 degrees C and heat-inactivated prior to testing. All BEs in buffer attracted neutrophils, with the greatest responses seen to S sanguis and B intermedius followed by A viscosus. Migration to all BEs in PHS was greater than in buffer, suggesting that all BEs are capable of generating serum chemoattractants. A viscosus BE activated serum attractants to the greatest degree. CFs of S sanguis, A viscosus, and to a lesser degree, Fusobacterium sp, also attracted neutrophils. Evidence from [3H]FMLP competitive ligand-binding assays indicated that S sanguis CFs contained low molecular weight (less than 700) chemoattractants, which were probably formylmethionyl oligopeptide-like materials. Of the bacteria associated with health, S sanguis and A viscosus appeared at least as able to generate chemoattractants during growth or with exposure to serum as bacteria associated with gingivitis. This observation suggests that these "healthy" bacteria, which are found in greater numbers with developing inflammation, may mediate increased neutrophil transmigration in early disease.
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Marasco WA, Phan SH, Krutzsch H, Showell HJ, Feltner DE, Nairn R, Becker EL, Ward PA. Purification and identification of formyl-methionyl-leucyl-phenylalanine as the major peptide neutrophil chemotactic factor produced by Escherichia coli. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(18)91029-x] [Citation(s) in RCA: 378] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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