RESUMO
Streptococcus gordonii and Streptococcus sanguinis are primary colonizers of the tooth surface. Although generally non-pathogenic in the oral environment, they are a frequent cause of infective endocarditis. Both streptococcal species express a serine-rich repeat surface adhesin that mediates attachment to sialylated glycans on mucin-like glycoproteins, but the specific sialoglycan structures recognized can vary from strain to strain. Previous studies have shown that sialoglycan binding is clearly important for aortic valve infections caused by some S. gordonii, but this process did not contribute to the virulence of a strain of S. sanguinis. However, these streptococci can bind to different subsets of sialoglycan structures. Here we generated isogenic strains of S. gordonii that differ only in the type and range of sialoglycan structures to which they adhere and examined whether this rendered them more or less virulent in a rat model of endocarditis. The findings indicate that the recognition of specific sialoglycans can either enhance or diminish pathogenicity. Binding to sialyllactosamine reduces the initial colonization of mechanically-damaged aortic valves, whereas binding to the closely-related trisaccharide sialyl T-antigen promotes higher bacterial densities in valve tissue 72 hours later. A surprising finding was that the initial attachment of streptococci to aortic valves was inversely proportional to the affinity of each strain for platelets, suggesting that binding to platelets circulating in the blood may divert bacteria away from the endocardial surface. Importantly, we found that human and rat platelet GPIbα (the major receptor for S. gordonii and S. sanguinis on platelets) display similar O-glycan structures, comprised mainly of a di-sialylated core 2 hexasaccharide, although the rat GPIbα has a more heterogenous composition of modified sialic acids. The combined results suggest that streptococcal interaction with a minor O-glycan on GPIbα may be more important than the over-all affinity for GPIbα for pathogenic effects.
Assuntos
Endocardite Bacteriana/imunologia , Glicoproteínas/imunologia , Ácidos Siálicos/imunologia , Infecções Estreptocócicas/imunologia , Streptococcus gordonii/imunologia , Streptococcus sanguis/imunologia , Animais , Modelos Animais de Doenças , Endocardite Bacteriana/patologia , Feminino , Humanos , Masculino , Ratos , Ratos Sprague-Dawley , Índice de Gravidade de Doença , Infecções Estreptocócicas/patologia , Streptococcus gordonii/patogenicidade , Streptococcus sanguis/patogenicidadeRESUMO
Streptococcus sanguinis is frequently isolated from the blood of patients with infective endocarditis and contributes to the pathology of this disease through induction of interleukin (IL)-1ß responsible for the development of the disease. However, the mechanism of IL-1ß induction remains unknown. In this study, S. sanguinis activated a murine dendritic cell (DC) to induce IL-1ß and this activity was attenuated by silencing the mRNAs of nucleotide-binding domain-like receptor containing protein 3 (NLRP3) and caspase-1. S. sanguinis induced IL-1ß production in murine bone marrow-derived macrophage, but this activity was significantly reduced in bone marrow-derived macrophages from NLRP3-, apoptosis-associated speck-like protein containing a caspase-recruitment domain-, and caspase-1-deficient mice. DC phagocytosed S. sanguinis cells, followed by the release of adenosine triphosphate (ATP). The ATP-degradating enzyme attenuated the release of ATP and IL-1ß. The inhibitors for ATP receptor reduced IL-1ß release in DC. These results strongly suggest that S. sanguinis has the activity to induce IL-1ß through the NLRP3 inflammasome in macrophage and DC and interaction of purinergic receptors with ATP released is involved in expression of the activity.
Assuntos
Células Dendríticas/imunologia , Inflamassomos/metabolismo , Interleucina-1beta/metabolismo , Macrófagos/imunologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Streptococcus sanguis/imunologia , Animais , Caspase 1/metabolismo , CamundongosRESUMO
Autoimmune and dysimmune inflammatory mechanisms on a genetically susceptible background are implicated in the etiology of Behçet's Disease (BD). Heat-shock protein-65 (HSP-65) derived from Streptococcus sanguinis was proposed as a triggering factor based on its homology with human HSP-60. However, none of the autoantigens identified so far in sera from BD share common epitopes with bacterial HSP-65 or has a high prevalence. Here, we report that sera from BD patients are immunoreactive against filamentous neuronal processes in the mouse brain, retina and scrotal skin in great majority of patients. By using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) and peptide mass fingerprinting, Western blotting and peptide blocking experiments, we have identified neurofilament medium (NF-M) as the probable antigen for the serologic response observed. Clustal Omega analyses detected significant structural homology between the human NF-M and bacterial HSP-65 corresponding to amino acids 111-126, 213-232 and 304-363 of mycobacterial HSP-65, which were previously identified to induce proliferation of lymphocytes obtained from BD patients. We also found that sera immunoreactive against NF-M cross-reacted with bacterial HSP-65. These findings suggest that NF-M may be involved in autoimmunity in BD due to its molecular mimicry with bacterial HSP-65.
Assuntos
Autoantígenos/imunologia , Proteínas de Bactérias/imunologia , Síndrome de Behçet/imunologia , Chaperonina 60/imunologia , Epitopos de Linfócito B/imunologia , Proteínas de Choque Térmico/imunologia , Proteínas de Neurofilamentos/imunologia , Neurônios/fisiologia , Streptococcus sanguis/imunologia , Adulto , Animais , Anticorpos/sangue , Autoantígenos/genética , Proteínas de Bactérias/genética , Encéfalo/patologia , Células Cultivadas , Chaperonina 60/genética , Reações Cruzadas , Epitopos de Linfócito B/genética , Feminino , Predisposição Genética para Doença , Proteínas de Choque Térmico/genética , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Homologia Estrutural de Proteína , Adulto JovemRESUMO
OBJECTIVES: To test the hypothesis that classical phagocytic functions are constitutively stimulated in patients with Behçet's disease (BD). METHODS: Four study groups were analysed: active BD (aBD; n=30), inactive BD (iBD; n=31); septic patients (SP; n=25); healthy controls (HC; n=30). Microbicide activity against Streptococcus pneumoniae, Streptococcus sanguinis and Candida albicans was determined by means of 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction and absorbance read by ELISA. Flow cytometry analysis evaluated phagocytosis (zymosan particles and microrganisms) and oxidative burst by dihidrorhodamine oxidation before and after stimulation with phorbol myristate acetate (PMA). The supernatant of PBMC cultures under TLR or microbial stimuli and of neutrophil cultures under PMA, LPS or microbial stimuli were used for determination of cytokine production by ELISA. RESULTS: We found no significant differences between the BD patient groups and control groups with regard to oxidative burst, phagocytic activity, microbicide activity or cytokine production. However, the cells from patients with severe BD (based on clinical manifestation) exhibit significantly higher oxidative burst activity, both before and after PMA stimulation, compared to cells from patients with mild BD. Furthermore, we found significant correlations between the BD patients' scores on the simplified Behçet's Disease Current Activity Form adapted for Portuguese (BR-BDCAFs) and Streptococcus sanguinis-stimulated production of IL23 by PBMC and IL8 by neutrophils, and between BR-BDCAFs score and constitutive production of TNF-α, IFNγ, IL6 and IL23 by PBMC. CONCLUSIONS: Patients with severe active BD do exhibit phagocytic dysfunction and some evidence of constitutive activation regarding oxidative burst and cytokine production.
Assuntos
Síndrome de Behçet/metabolismo , Citocinas/metabolismo , Mediadores da Inflamação/metabolismo , Leucócitos Mononucleares/metabolismo , Ativação de Neutrófilo , Neutrófilos/metabolismo , Fagocitose , Explosão Respiratória , Adulto , Síndrome de Behçet/diagnóstico , Síndrome de Behçet/imunologia , Candida albicans/imunologia , Estudos de Casos e Controles , Células Cultivadas , Citocinas/imunologia , Feminino , Humanos , Mediadores da Inflamação/imunologia , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/microbiologia , Masculino , Pessoa de Meia-Idade , Ativação de Neutrófilo/efeitos dos fármacos , Neutrófilos/efeitos dos fármacos , Neutrófilos/imunologia , Neutrófilos/microbiologia , Fagocitose/efeitos dos fármacos , Fenótipo , Explosão Respiratória/efeitos dos fármacos , Índice de Gravidade de Doença , Streptococcus pneumoniae/imunologia , Streptococcus sanguis/imunologia , Acetato de Tetradecanoilforbol/farmacologia , Adulto JovemRESUMO
BACKGROUND: Streptococcus sanguinis (S.sanguinis), a predominant bacterium in the human oral cavity, has been widely associated with the development of infective endocarditis. Platelets play both a haemostatic function and can influence both innate and adaptive immune responses. Previous studies have shown that S.sanguinis can interact with, and activate, platelets. RESULTS: The aim of this study was to determine whether S.sanguinis stimulates the release of matrix metalloproteinases (MMPs) 1, 2 and 9 and the pro-inflammatory mediators SDF-1, VEGF and sCD40L, from platelets and to subsequently pharmacologically address the release mechanism (s). S.sanguinis stimulated the release of MMP-1, SDF-1, VEGF and sCD40L from platelets and inhibitors of cyclooxygenase and phosphatidylinositol 3-kinase, and antagonists of the αIIbß3 integrin and glycoprotein Ib, each inhibited the secretion of all factors. CONCLUSIONS: Therefore the release of MMP-1, SDF-1, VEGF and sCD40L occurs late in the platelet response to S.sanguinis and highlights the complex intracellular signalling pathways stimulated in response to S.sanguinis which lead to haemostasis, MMP and pro-inflammatory mediator secretion.
Assuntos
Plaquetas/imunologia , Plaquetas/metabolismo , Citocinas/metabolismo , Metaloproteinase 1 da Matriz/metabolismo , Streptococcus sanguis/imunologia , Biomarcadores/metabolismo , Humanos , Mediadores da Inflamação/metabolismo , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Ativação Plaquetária/imunologiaRESUMO
BACKGROUND AND OBJECTIVE: Smoking has been reported to increase the risk of periodontal disease by disrupting the balance of immune responses and tissue repair processes; however, this risk varies among smokers. Cotinine levels in saliva are routinely used to measure the level of smoking, and reflect the quantity of nicotine, and other smoking-related xenobiotics that challenge host systems. This study delineated characteristics of inflammatory mediators in saliva and serum antibody responses to both periodontal pathogens and commensal bacteria in smokers as they related to cotinine levels. MATERIALS AND METHODS: This case-control study (n = 279) examined salivary inflammatory mediator responses [interleukin (IL)-1ß, IL-10, prostaglandin E2, myeloperoxidase and plasminogen activator inhibitor-1], and serum IgG antibody responses to three periodontal pathogens (Aggregatibacter actinomyce-temcomitans, Porphyromonas gingivalis, Treponema denticola) and five commensal oral microorganisms (Veillonella parvula, Streptococcus sanguis, Prevotella loescheii, Actinomyces naeslundii, Capnocytophaga ochracea). RESULTS: The patients were stratified into health (n = 30), gingivitis (n = 55) and periodontitis (n = 184); cotinine levels correlated with reported smoking habits in health, less so with gingivitis, and were not correlated in periodontitis. Of the inflammatory mediators/acute phase proteins, only IL-1ß levels were positively associated (p < 0.001) with the pack years and cotinine levels. As might be predicted, patients with periodontitis smoked more (p < 0.001) and had higher levels of cotinine. IL-1ß and antibody to A. actinomycetemcomitans, P. gingivalis and T. denticola were significantly higher in the patients with periodontitis than either patients with gingivitis or who were healthy. CONCLUSIONS: Generally, antibody to the pathogens and commensals was lower with decreased cotinine levels. Smoking exacerbated differences in both inflammatory mediators and three antibody in periodontal disease compared to healthy subjects.
Assuntos
Cotinina/análise , Mediadores da Inflamação/análise , Saliva/química , Fumar/metabolismo , Actinomyces/imunologia , Adulto , Idoso , Aggregatibacter actinomycetemcomitans/imunologia , Anticorpos Antibacterianos/sangue , Capnocytophaga/imunologia , Estudos de Casos e Controles , Dinoprostona/análise , Feminino , Gengivite/metabolismo , Gengivite/microbiologia , Humanos , Imunoglobulina G/sangue , Interleucina-10/análise , Interleucina-1beta/análise , Masculino , Pessoa de Meia-Idade , Periodontite/metabolismo , Periodontite/microbiologia , Peroxidase/análise , Inibidor 1 de Ativador de Plasminogênio/análise , Porphyromonas gingivalis/imunologia , Prevotella/imunologia , Saliva/microbiologia , Fumar/imunologia , Streptococcus sanguis/imunologia , Treponema denticola/imunologia , Veillonella/imunologia , Adulto JovemRESUMO
Bacterial lipoproteins/lipopeptides inducing host innate immune responses are sensed by mammalian Toll-like receptor 2 (TLR2). These bacterial lipoproteins are structurally divided into two groups, diacylated or triacylated lipoproteins, by the absence or presence of an amide-linked fatty acid. The presence of diacylated lipoproteins has been predicted in low-GC content gram-positive bacteria and mycoplasmas based on the absence of one modification enzyme in their genomes; however, we recently determined triacylated structures in low-GC gram-positive Staphylococcus aureus, raising questions about the actual lipoprotein structure in other low-GC content gram-positive bacteria. Here, through intensive MS analyses, we identified a novel and unique bacterial lipoprotein structure containing an N-acyl-S-monoacyl-glyceryl-cysteine (named the lyso structure) from low-GC gram-positive Enterococcus faecalis, Bacillus cereus, Streptococcus sanguinis, and Lactobacillus bulgaricus. Two of the purified native lyso-form lipoproteins induced proinflammatory cytokine production from mice macrophages in a TLR2-dependent and TLR1-independent manner but with a different dependence on TLR6. Additionally, two other new lipoprotein structures were identified. One is the "N-acetyl" lipoprotein structure containing N-acetyl-S-diacyl-glyceryl-cysteine, which was found in five gram-positive bacteria, including Bacillus subtilis. The N-acetyl lipoproteins induced the proinflammatory cytokines through the TLR2/6 heterodimer. The other was identified in a mycoplasma strain and is an unusual diacyl lipoprotein structure containing two amino acids before the lipid-modified cysteine residue. Taken together, our results suggest the existence of novel TLR2-stimulating lyso and N-acetyl forms of lipoproteins that are conserved in low-GC content gram-positive bacteria and provide clear evidence for the presence of yet to be identified key enzymes involved in the bacterial lipoprotein biosynthesis.
Assuntos
Bactérias Gram-Positivas/imunologia , Macrófagos Peritoneais/imunologia , Macrófagos Peritoneais/microbiologia , Receptor 2 Toll-Like/imunologia , Receptor 2 Toll-Like/metabolismo , Animais , Bacillus cereus/imunologia , Bacillus cereus/metabolismo , Bacillus subtilis/imunologia , Bacillus subtilis/metabolismo , Enterococcus faecalis/imunologia , Enterococcus faecalis/metabolismo , Geobacillus/imunologia , Geobacillus/metabolismo , Bactérias Gram-Positivas/metabolismo , Lactobacillus/imunologia , Lactobacillus/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Pneumonia por Mycoplasma/imunologia , Pneumonia por Mycoplasma/metabolismo , Streptococcus sanguis/imunologia , Streptococcus sanguis/metabolismo , Receptor 1 Toll-Like/genética , Receptor 1 Toll-Like/imunologia , Receptor 1 Toll-Like/metabolismo , Receptor 2 Toll-Like/genética , Receptor 6 Toll-Like/genética , Receptor 6 Toll-Like/imunologia , Receptor 6 Toll-Like/metabolismoRESUMO
BACKGROUND: Infectious agents, especially Streptococcus sanguinis and herpes simplex virus, have long been postulated as major triggering factors for Behçet disease (BD). OBJECTIVES: To identify an anti-S. sanguinis antigen reacting with serum IgA antibody in patients with BD. METHODS: We detected a target protein by proteomics analysis and evaluated serum IgA reactivity of 100 patients with BD against the identified streptococcal target protein and human heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1. Homologous epitope sequences between the streptococcal target protein and human hnRNP A2/B1 were also evaluated. RESULTS: Four protein bands were detected by immunoprecipitation, and chaperonin GroEL was identified by a proteomics analysis. Reactivity of serum IgA against recombinant S. sanguinis GroEL was detected in 77 of 100 patients with BD (77%) and in 21 of 70 healthy controls (30%). In addition, reactivity of serum IgA against human recombinant hnRNP A2/B1 was seen in 79 of 100 patients with BD (79%) and in eight of 70 healthy controls (11%). Among the eight distinctive epitopes with significant homology between S. sanguinis GroEL and human hnRNP A2/B1, the serum IgA reactivity of patients with BD was markedly higher with epitope 3 (hnRNP A2/B1 peptide 33-46 and GroEL peptide 57-70) and epitope 6 (hnRNP A2/B1 peptide 177-188 and GroEL peptide 347-358). CONCLUSION: We identified an S. sanguinis GroEL protein as a target of serum anti-S. sanguinis IgA antibody reactivity in patients with BD. In addition, patients with BD exhibited serum IgA reactivity against homologous epitope regions between S. sanguinis GroEL and human hnRNP A2/B1.
Assuntos
Proteínas de Bactérias/imunologia , Síndrome de Behçet/imunologia , Chaperonina 60/imunologia , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/imunologia , Imunoglobulina A/sangue , Streptococcus sanguis/imunologia , Adulto , Síndrome de Behçet/etiologia , Estudos de Casos e Controles , Epitopos/imunologia , Feminino , Humanos , Imunoprecipitação/métodos , Masculino , Pessoa de Meia-IdadeRESUMO
OBJECTIVES: Heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 has been identified as a target antigen of anti-endothelial cell immunglobulin (Ig)A antibodies in patients with Behçet's disease (BD). The aim was to investigate the effects of the sera from BD patients and Streptococcus sanguis on the subcellular expression of hnRNP A2/B1 in human dermal microvascular endothelial cells (HDMECs). METHOD: The sera of BD patients and healthy controls (HC) as well as cultured S. sanguis were used to stimulate HDMECs. Subcellular fractions were obtained from stimulated HDMECs and were subjected to immunoblot analyses. The distribution of hnRNP A2/B1 was investigated by immunocytochemistry and direct immunofluorescence study was performed in biopsy specimens of mucosal ulcers from BD patients. RESULTS: BD patients' sera increased the membrane expression of hnRNP A2/B1 in HDMECs after 12 and 24 h of incubation compared with HDMECs incubated with endothelial cell culture media and HC sera. S. sanguis also increased hnRNP A2/B1 in the cellular membrane. hnRNP A2/B1 mRNA level was also significantly upregulated in HDMECs incubated with BD patients' sera and S. sanguis. Immunocytochemistry demonstrated marked expression of hnRNP A2/B1 in the cytoplasm and cellular membrane of HDMECs incubated with BD patients' sera or S. sanguis. In addition, direct immunofluorescence experiments revealed the co-localization of serum IgA antibodies and monoclonal antibodies (mAbs) against hnRNP A2/B1 in tissue sections from ulcers of BD patients. CONCLUSIONS: Our data indicate that both the sera of BD patients with active disease and S. sanguis infection are inflammatory stimuli that can induce membranous hnRNP A2/B1 expression in HDMECs.
Assuntos
Síndrome de Behçet/imunologia , Células Endoteliais/metabolismo , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/metabolismo , Streptococcus sanguis/imunologia , Estudos de Casos e Controles , Membrana Celular/metabolismo , Células Cultivadas , Técnica Direta de Fluorescência para Anticorpo , HumanosRESUMO
Gingival tissue faces constant exposure to micro-organisms. It functions as part of the host response, an anti-microbial barrier that recognizes and discriminates between commensal and pathogenic bacteria. This study aimed to evaluate and compare the effects of cell wall extracts from different periodontal bacteria, commensals Streptococcus sanguinis and Fusobacterium nucleatum and the pathogen Porphyromonas gingivalis, on the innate immune response of gingival keratinocytes and the role of TLR2 in regulating this. We assayed mRNA levels to determine the expression of human beta-defensins (hbetaD2, hbetaD3), interleukin-1alpha, -1beta, 6 and 8 and matrix metalloproteinase-9. F. nucleatum extracts induced beta-defensin and inflammatory marker mRNA expression at higher levels than P. gingivalis. Extracts from the Gram-positive commensal S. sanguinis did not upregulate the host response. TLR2 extinction inhibited the upregulation of beta-defensin and cytokine transcripts by F. nucleatum extracts but, in contrast, led to a weak induction of hbetaD3 after challenge with S. sanguinis extracts. Although F. nucleatum strongly induces innate immune and inflammatory mediators, S. sanguinis limits their expression through TLR2. Together, our data demonstrate that gingival keratinocytes recognize and discriminate between Gram-positive and Gram-negative commensal extracts, in part through TLR2, to activate different signaling pathways of the innate immune host response.
Assuntos
Fusobacterium nucleatum/imunologia , Gengiva/imunologia , Imunidade Inata/imunologia , Streptococcus sanguis/imunologia , Receptor 2 Toll-Like/imunologia , Biomarcadores/metabolismo , Parede Celular/química , Parede Celular/imunologia , Células Cultivadas , Fusobacterium nucleatum/citologia , Inativação Gênica , Gengiva/citologia , Gengiva/microbiologia , Humanos , Inflamação/imunologia , Interleucina-8/genética , Interleucina-8/imunologia , Queratinócitos/citologia , Queratinócitos/imunologia , Metaloproteinase 9 da Matriz/genética , Metaloproteinase 9 da Matriz/metabolismo , Interferência de RNA , Transdução de Sinais/fisiologia , Streptococcus sanguis/citologia , Receptor 2 Toll-Like/genética , beta-Defensinas/genética , beta-Defensinas/imunologiaRESUMO
PURPOSE: Mechanisms underlying systemic infections by oral species of Mitis (Streptococcus mitis, Streptococcus oralis) and Sanguinis (Streptococcus gordonii, Streptococcus sanguinis) commensal streptococci are poorly understood. This study investigates profiles of susceptibility to complement-mediated host immunity in representative strains of these four species, which were isolated from oral sites or from the bloodstream. METHODOLOGY: Deposition of complement opsonins (C3b/iC3b), and surface binding to C-reactive protein (CRP) and to IgG antibodies were quantified by flow cytometry in 34 strains treated with human serum (HS), and compared to rates of opsonophagocytosis by human PMN mediated by complement (CR1/3) and/or IgG Fc (FcγRII/III) receptors. RESULTS: S. sanguinis strains showed reduced susceptibility to complement opsonization and low binding to CRP and to IgG compared to other species. Surface levels of C3b/iC3b in S. sanguinis strains were 4.5- and 7.8-fold lower than that observed in S. gordonii and Mitis strains, respectively. Diversity in C3b/iC3b deposition was evident among Mitis species, in which C3b/iC3b deposition was significantly associated with CR/FcγR-dependent opsonophagocytosis by PMN (P<0.05). Importantly, S. gordonii and Mitis group strains isolated from systemic infections showed resistance to complement opsonization when compared to oral isolates of the respective species (P<0.05). CONCLUSIONS: This study establishes species-specific profiles of susceptibility to complement immunity in Mitis and Sanguinis streptococci, and indicates that strains associated with systemic infections have increased capacity to evade complement immunity. These findings highlight the need for studies identifying molecular functions involved in complement evasion in oral streptococci.
Assuntos
Complemento C3b/imunologia , Variação Genética , Boca/microbiologia , Estreptococos Viridans/genética , Estreptococos Viridans/imunologia , Aderência Bacteriana , Biofilmes , Proteína C-Reativa/metabolismo , Humanos , Evasão da Resposta Imune , Imunoglobulina G/imunologia , Neutrófilos/imunologia , Neutrófilos/microbiologia , Fagocitose , Infecções Estreptocócicas/sangue , Infecções Estreptocócicas/imunologia , Streptococcus gordonii/genética , Streptococcus gordonii/imunologia , Streptococcus mitis/genética , Streptococcus mitis/imunologia , Streptococcus sanguis/genética , Streptococcus sanguis/imunologiaRESUMO
BACKGROUND AND OBJECTIVE: Oral epithelial cells may be invaded by a polymicrobial intracellular flora, including pathogens together with commensals. Various oral pathogens can induce the production of interleukin-8, a potent neutrophil chemotractant, in oral epithelial cells. Evidence from the gut suggests that commensal species may modulate inflammatory responses to pathogens. The aim of this study was to examine the interleukin-8 responses of oral epithelial cells to an oral pro-inflammatory species, Fusobacterium nucleatum, in combination with an oral commensal, Streptococcus cristatus. MATERIAL AND METHODS: KB, TERT-2, TR146 and SCC15 cells were cocultured with F. nucleatum and S. cristatus, either alone or in combination, at 37 degrees C in 5% CO2 under various conditions. The mRNA expression of interleukin-8 was analyzed by reverse transcription-polymerase chain reaction and protein secretion was measured by enzyme-linked immunosorbent assay. RESULTS: F. nucleatum alone evoked a potent interleukin-8 response, whereas S. cristatus alone did not induce significant interleukin-8 expression in oral epithelial cells. When present together, S. cristatus attenuated the F. nucleatum-induced interleukin-8 production in the four oral epithelial cell lines to varying degrees. The inhibitory effect of S. cristatus was independent of its viability and its co-aggregation with F. nucleatum, was not related to soluble bacterial products and appeared to require bacterial contact with epithelial cells. Similar effects were seen with several other species of oral streptococci. CONCLUSION: Our data suggest that S. cristatus may exert immunomodulatory effects on the interleukin-8 response of oral epithelial cells to F. nucleatum challenge.
Assuntos
Fusobacterium nucleatum/imunologia , Interleucina-8/biossíntese , Mucosa Bucal/microbiologia , Streptococcus/fisiologia , Aggregatibacter actinomycetemcomitans/imunologia , Anticorpos Antibacterianos/imunologia , Canavanina/imunologia , Linhagem Celular , Técnicas de Cocultura , Eikenella corrodens/imunologia , Células Epiteliais/imunologia , Células Epiteliais/microbiologia , Humanos , Fatores Imunológicos/imunologia , Células KB , Boca/microbiologia , Mucosa Bucal/imunologia , Porphyromonas gingivalis/imunologia , Prevotella intermedia/imunologia , Streptococcus gordonii/imunologia , Streptococcus intermedius/imunologia , Streptococcus mitis/imunologia , Streptococcus mutans/imunologia , Streptococcus oralis/imunologia , Streptococcus sanguis/imunologia , Streptococcus sobrinus/imunologiaRESUMO
Behçet's disease (BD) is still considered as a mysterious multisystemic disorder characterized by recurrent involvement of muco-cutaneous, ocular, intestinal, vascular and/or nervous system organs. In this review, we would like to highlight and discuss several important advances in our understanding of the pathogenesis of BD based on the intrinsic genetic factors including HLA-B51 and MICA expression and extrinsic triggering factors. As one of the extrinsic triggering factors, we focused on the hypersensitivity against oral streptococci which might be acquired through the innate immune mechanism. It was found that HLA-B51 restricted CD8 T cell response was clearly correlated with the target tissues expressing MICA*009 by stress in active BD patients with HLA-B51 as the intrinsic factors. Bes-1 gene and HSP-65 derived from oral S. sanguinis, which is the uncommon serotype (KTH-1, strain BD113-20), are supposed to play important roles as an extrinsic factor in BD pathogenesis. The peptides of the Bes-1 gene are highly homologous with the retinal protein Brn3b and moreover, the Bes-1 peptides were homologous with HSP-65 derived from microorganisms in association with the counterpart human HSP-60, which appeared reactively in the patients. HSP-65/60 also has high homologies with the respective T cell epitope of BD patients. Although HSP-65/60 and the peptides of Bes-1 gene were found to stimulate PBMCs from BD patients in the production of pro-inflammatory Th1 type cytokines, some homologous peptides of HSP-65 with T cell epitopes were found to reduce IL-8, IL-12 and TNF-alpha produced from PBMCs of active BD patients. The findings might be correlated with the clinically therapeutic effects for BD patients with severe uveitis, who were led to immunotolerance by the peptide of human HSP-60 (336-351), as previously reported. Then, the pathogenesis of BD was discussed referring to intrinsic genetic factors and extrinsic triggering factors in aspects of streptococcal hypersensitivity, which might be acquired through the innate immune mechanisms. The BD symptoms were thought to be due to vascular reactions as immune responses in correlation with monocyte expressed streptococcal agents.
Assuntos
Síndrome de Behçet/etiologia , Infecções Estreptocócicas/imunologia , Streptococcus sanguis/imunologia , Síndrome de Behçet/imunologia , Chaperonina 60/imunologia , Proteínas de Choque Térmico/imunologia , HumanosRESUMO
Infective endocarditis is caused by Streptococcus sanguinis present in dental plaque, which can induce inflammatory responses in the endocardium. The present study depicts research on the properties of apigenin in embryonic mouse heart cells (H9c2) treated with lipoteichoic acid (LTA) obtained from S. sanguinis. Interleukin-1ß and cyclooxygenase (COX)-2 expression were detected by reverse transcriptase polymerase chain reaction. In addition, western blot assays and immuno-fluorescence staining were used to assess translocation of nuclear factor kappa beta (NF-κB), degradation of IκB, as well as activity of the mitogen activated protein kinases: extracellular signal-regulated kinase (ERK)1/2, p38, and c-Jun N-terminal kinase (JNK). Effect of apigenin on cell viability was equally assessed in other experimental series. Our results showed that apigenin blocked activation of ERK, JNK, and p38 in cardiomyocytes treated with LTA in a dose-dependent fashion. Moreover, apigenin showed no cytotoxic effects; it blocked NF-κB translocation and IκB degradation. Our findings suggested that apigenin possessed potential value in the treatment of infectious endocarditis.
Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Apigenina/farmacologia , Endocardite Bacteriana/tratamento farmacológico , Mioblastos Cardíacos/efeitos dos fármacos , Streptococcus sanguis/imunologia , Animais , Anti-Inflamatórios não Esteroides/uso terapêutico , Apigenina/uso terapêutico , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Ciclo-Oxigenase 2/metabolismo , Endocardite Bacteriana/microbiologia , Quinase I-kappa B/metabolismo , Interleucina-1beta/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno , Lipopolissacarídeos/imunologia , Camundongos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Mioblastos Cardíacos/imunologia , NF-kappa B/metabolismo , Ratos , Transdução de Sinais , Ácidos Teicoicos/imunologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Adamantiades-Behcet's disease (ABD) is a chronic inflammatory multisystem disorder. Although the precise etiology is unclear, high prevalence of human leukocyte antigen (HLA)-B51 predisposition and predominantly involved T-helper type 1 cells (Th1)-type proinflammatory cytokines and extrinsic Streptococcal infection suggest a substantial association with an immunogenetic basis and strengthens the hypothesis that IL-12, a potent inducer of Th-1 immune reaction, is a putative candidate in its pathogenesis. These clinicopathological findings led us to examine interleukin 12 p40 (IL-12B) promoter polymorphism, for which the 4-base pair (bp) heterozygous insertion has been shown to affect the gene transcription and subsequent protein production. We analyzed IL-12B promoter genotypes in 194 Japanese subjects (92 with ABD and 102 normal controls) by PCR-based restriction enzyme digestion. The frequency of the insertion heterozygosity was significantly higher in patients than in controls (49/92, 53.3% vs 39/102, 38.2%, respectively). Comparing these with HLA haplotype data, this trend was more significant in HLA-B51-negative patients (29/42, 69.0% vs 20/50, 40.0%; P = 0.005). As assessed by semiquantitative reverse transcription-PCR and ELISA, stimulation with Streptococcal antigens specifically increased expression of IL-12 p40 mRNA and protein, in conjunction with IL-12 p70 induction, in peripheral blood mononuclear cells from heterozygous patients. Our results provide evidence for anti-bacterial host response toward Th1-immunity mediated by IL-12 in patients with ABD, and the possible insight into the genetic susceptibility that is independent of HLA background.
Assuntos
Antígenos de Bactérias/imunologia , Síndrome de Behçet/genética , Predisposição Genética para Doença/genética , Interleucina-12/genética , Polimorfismo Genético , Regiões Promotoras Genéticas/genética , Subunidades Proteicas/genética , Streptococcus sanguis/imunologia , Células Th1/imunologia , Adulto , Idoso , Síndrome de Behçet/imunologia , Síndrome de Behçet/fisiopatologia , Estudos de Casos e Controles , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Feminino , Regulação da Expressão Gênica , Antígenos HLA-B/genética , Antígenos HLA-B/imunologia , Antígeno HLA-B51 , Heterozigoto , Humanos , Interleucina-12/fisiologia , Subunidade p40 da Interleucina-12 , Leucócitos Mononucleares , Masculino , Pessoa de Meia-Idade , Subunidades Proteicas/fisiologia , RNA Mensageiro/análise , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Infecções Estreptocócicas/imunologia , Infecções Estreptocócicas/fisiopatologiaRESUMO
Yanagihori et al. found an HLA-independent higher frequency of IL-12B promoter polymorphism in Adamantiades-Behçet's disease (ABD) patients than in controls. Stimulation with streptococcal antigens specifically increased expression of patients' peripheral blood mononuclear cells IL-12 p40/p70. The authors provide evidence for an antibacterial host response toward T-helper type 1 immunity mediated by IL-12 in patients with ABD, which is HLA independent.
Assuntos
Síndrome de Behçet/imunologia , Síndrome de Behçet/fisiopatologia , Antígenos HLA/imunologia , Interleucina-12/fisiologia , Células Th1/imunologia , Antígenos de Bactérias/imunologia , Síndrome de Behçet/genética , Biomarcadores Tumorais/fisiologia , Proteínas de Ligação a DNA/fisiologia , Regulação da Expressão Gênica/imunologia , Predisposição Genética para Doença/genética , Antígenos HLA/genética , Heterozigoto , Humanos , Interleucina-12/genética , Mycoplasma fermentans/imunologia , Fosfopiruvato Hidratase/fisiologia , Polimorfismo Genético , Regiões Promotoras Genéticas/genética , Infecções Estreptocócicas/imunologia , Streptococcus sanguis/imunologia , Células Th1/fisiologia , Proteínas Supressoras de Tumor/fisiologiaRESUMO
Salivary proteins modulate bacterial colonization in the oral cavity and interact with systemic pathogens that pass through the oropharynx. An interesting example is the opportunistic respiratory pathogen Streptococcus pneumoniae that normally resides in the nasopharynx, but belongs to the greater Mitis group of streptococci, most of which colonize the oral cavity. Streptococcus pneumoniae also expresses a serine-rich repeat (SRR) adhesin, PsrP, which is a homologue to oral Mitis group SRR adhesins, such as Hsa of Streptococcus gordonii and SrpA of Streptococcus sanguinis. As the latter bind to salivary glycoproteins through recognition of terminal sialic acids, we wanted to determine whether S. pneumoniae also binds to salivary proteins through possibly the same mechanism. We found that only a capsule-free mutant of S. pneumoniae TIGR4 binds to salivary proteins, most prominently to mucin MUC7, but that this binding was not mediated through PsrP or recognition of sialic acid. We also found, however, that PsrP is involved in agglutination of human red blood cells (RBCs). After removal of PsrP, an additional previously masked lectin-like adhesin activity mediating agglutination of sialidase-treated RBCs becomes revealed. Using a custom-spotted glycoprotein and neoglycoprotein dot blot array, we identify candidate glycan motifs recognized by PsrP and by the putative S. pneumoniae adhesin that could perhaps be responsible for pneumococcal binding to salivary MUC7 and glycoproteins on RBCs.
Assuntos
Cápsulas Bacterianas/metabolismo , Mucinas/metabolismo , Proteínas e Peptídeos Salivares/metabolismo , Streptococcus pneumoniae/metabolismo , Adesinas Bacterianas/genética , Adesinas Bacterianas/metabolismo , Antígenos de Bactérias/imunologia , Antígenos de Bactérias/metabolismo , Aderência Bacteriana/fisiologia , Hemaglutinação/imunologia , Humanos , Proteínas Imobilizadas , Proteínas de Membrana/imunologia , Proteínas de Membrana/metabolismo , Boca/microbiologia , Mucinas/imunologia , Mutação , Ácido N-Acetilneuramínico/metabolismo , Nasofaringe/microbiologia , Proteínas e Peptídeos Salivares/imunologia , Streptococcus pneumoniae/genética , Streptococcus pneumoniae/imunologia , Streptococcus sanguis/genética , Streptococcus sanguis/imunologia , Streptococcus sanguis/metabolismoRESUMO
Immune reactions against microorganisms play an important pathogenic role in Adamantiades-Behçet's disease. We had previously obtained Streptococcus sanguinis (strain BD113-20), isolated from the oral cavity of patients with Adamantiades-Behçet's syndrome. To investigate the pathogenesis of this isolate, we examined neutrophil reactions and levels of cytokine production by lymphocytes after stimulation with the strain. The reactions of neutrophils were examined by chemiluminescence assay using whole blood. The amounts of interferon gamma (IFN-gamma) and interleukin (IL)-4, IL-8, IL-10 and IL-12, produced by peripheral blood mononuclear cells, were measured by ELISA. Strain BD113-20 activated neutrophils from Adamantiades-Behçet's patients and healthy volunteers, and, in addition it increased the IFN-gamma production by lymphocytes. Lymphocytes from Adamantiades-Behçet's patients showed a dominant T helper-1 immune response. Results indicated that both bacterial stimulation and host hypersensitivity might be involved in the symptoms and pathogenesis of Adamantiades-Behçet's disease.
Assuntos
Síndrome de Behçet/imunologia , Linfócitos/imunologia , Neutrófilos/imunologia , Infecções Estreptocócicas/imunologia , Streptococcus sanguis/imunologia , Adulto , Idoso , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Hipersensibilidade , Interferon gama/análise , Interleucinas/análise , Medições Luminescentes , Masculino , Pessoa de Meia-Idade , BocaRESUMO
Complement system activation has been shown to be involved in inflammation and regeneration processes that can be observed within the dental pulp after moderate carious decay. Studies simulating carious injuries in vitro have shown that when human pulp fibroblasts are stimulated by lipoteichoic acid (LTA), they synthetize all complement components. Complement activation leads to the formation of the membrane attack complex (MAC), which is known for its bacterial lytic effect. This work was designed to find out whether human pulp fibroblasts can kill Streptococcus mutans and Streptococcus sanguinis via complement activation. First, histological staining of carious tooth sections showed that the presence of S. mutans correlated with an intense MAC staining. Next, to simulate bacterial infection in vitro, human pulp fibroblasts were incubated in serum-free medium with LTA. Quantification by an enzymatic assay showed a significant increase of MAC formation on bacteria grown in this LTA-conditioned medium. To determine whether the MAC produced by pulp fibroblasts was functional, bacteria sensitivity to LTA-conditioned medium was evaluated using agar well diffusion assay and succinyl dehydrogenase (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide [MTT]) assay. Both assays showed that S. mutans and S. sanguinis were sensitive to LTA-conditioned medium. Finally, to evaluate whether MAC formation on cariogenic bacteria, by pulp fibroblasts, can be directly induced by the presence of these bacteria, a specific coculture model of human pulp fibroblasts and bacteria was developed. Immunofluorescence revealed an intense MAC labeling on bacteria after direct contact with pulp fibroblasts. The observed MAC formation and its lethal effects were significantly reduced when CD59, an inhibitor of MAC formation, was added. Our findings demonstrate that the MAC produced by LTA-stimulated pulp fibroblasts is functional and can kill S. mutans and S. sanguinis. Taken together, these data clearly highlight the function of pulp fibroblasts in destroying cariogenic bacteria.
Assuntos
Ativação do Complemento/fisiologia , Cárie Dentária/microbiologia , Polpa Dentária/citologia , Fibroblastos/fisiologia , Células Cultivadas , Complexo de Ataque à Membrana do Sistema Complemento/imunologia , Complexo de Ataque à Membrana do Sistema Complemento/fisiologia , Polpa Dentária/fisiologia , Fibroblastos/imunologia , Imunofluorescência , Humanos , Streptococcus mutans/imunologia , Streptococcus sanguis/imunologiaRESUMO
A simple method for obtaining an active preparation of IgA-specific protease from a bacterial source is presented. In this method Streptococcus sanguis was inoculated onto the surface of a dialysis membrane on nutrient agar. Following growth, the membrane was removed from the agar surface and washed in a small volume of buffer. A solution with protease activity against IgA1 monoclonal proteins was obtained by clarification of the wash and appeared to be similar to enzyme preparations obtained by other methods.