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1.
Actinobacillus actinomycetemcomitans is considered to be an aetiological agent in various forms of periodontitis, with serotype b-specific carbohydrate being the immunodominant antigen of A. actinomycetemcomitans Y4 in high-responder patients. Lipopolysaccharide (LPS) of the organism may also be an important antigen. The purpose of the present study was to clarify the importance of LPS as an antigen of A. actinomycetemcomitans. Twenty patients who had high antibody titres to strain Y4 were selected, and the reactivity of their sera with LPS was determined by ELISA and Western blotting. Two groups of patients were observed: group 1 had high IgG titres only to serotype b strain, whereas group 2 had high IgG titres to serotypes a, b and c strains. The results of adsorption tests showed that anti-A. actinomycetemcomitans Y4 antibody in group 1 patients mostly consisted of antibody reactive with the serotype b-specific carbohydrate, whereas the antibody in group 2 patients mostly consisted of antibody reactive with the LPS of all serotypes. These data show that anti-LPS antibody is present and predominant in anti-A. actinomycetemcomitans Y4 antibody from some high-responder patients, and indicate an important role for LPS as an antigen in the humoral immune response to the organism.  相似文献   

2.
The serotype c antigen of Actinobacillus actinomycetemcomitans consists of 6-deoxy-l-talose. A gene cluster involved in the synthesis of serotype-specific polysaccharide antigen was cloned from the chromosomal DNA of A. actinomycetemcomitans NCTC 9710 (serotype c). This cluster consisted of 17 open reading frames. Escherichia coli produced the polysaccharide that reacts with the serotype c-specific antibody when transformed with a plasmid containing the cluster. Comparing the structure of the gene cluster with a similar cluster from A. actinomycetemcomitans Y4 (serotype b), which produces a polysaccharide consisting of l-rhamnose and d-fucose, revealed that a 5.7 kb region containing seven genes in the cluster from strain Y4 was replaced by a 3.8 kb region containing three genes in strain NCTC 9710. The results suggest that these region, as well as dTDP-6-deoxy-l-talose-forming dTDP-4-keto-l-rhamnose reductase, is essential to the production of extracellular polysaccharide specific to serotype c.  相似文献   

3.
The serotype b-specific carbohydrate antigen (SbAg) of Actinobacillus actinomycetemcomitans Y4 is reported to be the O antigen of lipopolysaccharide, and the highest titers of serum antibody reactive with A. actinomycetemcomitans in early-onset periodontitis (EOP) patients bind SbAg. These high titers of serum antibody reactive with SbAg are associated with a lesser extent and severity of periodontal disease. The aim of this study was to determine if a limited number of genes code for anti-SbAg antibodies as has been shown for immunoglobulin G (IgG) reactive with the type b polysaccharide from Haemophilus influenzae. Serum IgG reactive with the SbAg was prepared from 20 high-titer EOP patients by affinity chromatography. The IgG subclass concentrations were determined, and heterogeneity was analyzed by isoelectric focusing (IEF). IgG2 was the dominant subclass (83% of total IgG) in the anti-SbAg IgG fraction and represented an average of 1.33% of total serum IgG2. The IgG2 reactive with SbAg was isolated from the affinity-purified IgG fraction by affinity chromatography with protein A and subclass-specific monoclonal antibodies. On IEF gels, only 4 to 20 bands were observed in the anti-SbAg IgG fractions, indicating limited heterogeneity. N-terminal amino acid sequence analysis of eight representative anti-SbAg IgG2 preparations indicated that variable heavy and light chains consisted largely of V(H)III and V(kappa)II, respectively. However, a significant fraction of anti-SbAg may use V(H) and V(lambda) genes with blocked N termini. In short, these findings indicate that IgG reactive with SbAg is very much like the antibody reactive with H. influenzae type b polysaccharide. Similarities include IgG2 dominance, limited bands on IEF gels, supporting an oligoclonal response, and use of genes from V(H)III and V(kappa)II regions.  相似文献   

4.
Sera of localized juvenile periodontitis (LJP) patients colonized by Actinobacillus actinomycetemcomitans serotype b often contain markedly elevated levels of immunoglobulin G (IgG) antibodies to serospecific determinants in the O polysaccharide of lipopolysaccharide (LPS), as well as to outer membrane proteins of this species. IgG antibodies in LJP sera are known to opsonize A. actinomycetemcomitans for subsequent phagocytosis and killing by human neutrophils. The objective of this study was to determine whether outer membrane proteins or serospecific determinants in LPS are the primary target for opsonic IgG antibodies in LJP sera. An A. actinomycetemcomitans serotype b O-polysaccharide affinity column was constructed and subsequently used to purify LPS-specific IgG antibodies from LJP serum. The affinity-purified anti-LPS IgG antibodies were enriched in content of IgG2 (66.2%, compared with 37.0% in the total IgG fraction) and were immunospecific for A. actinomycetemcomitans serotype b LPS. In an opsonophagocytic assay using neutrophils from donors who were homozygous for the H131 allotype of Fcy receptor IIa (CD32), it was found that LPS-specific IgG antibodies exhibited substantially greater opsonic activity toward A. actinomycetemcomitans serotype b than an LJP IgG fraction that was depleted of LPS-reactive antibodies but contained antibodies against outer membrane proteins of this species. The results of this study indicate that serospecific determinants in the O polysaccharide of A. actinomycetemcomitans serotype b are a principal target for opsonic antibodies in sera of LJP subjects.  相似文献   

5.
The extracellular antigens of Actinobacillus actinomycetemcomitans Y4 (serotype b) contain a 37-kDa protein which is a major target for IgGs from patients suffering from severe alveolar bone loss. Since the 37-kDa protein has not been studied sufficiently, our investigation focused on its characteristics, e.g., its localization, specificity, and whether it directly stimulates macrophages to produce cytokines. The 37-kDa protein was purified from the culture supernatant of the Y4 strain by means of chromatofocusing and gel filtration. The 37-kDa protein is a unique glycoprotein which forms immune complexes with monoclonal antibodies against rhamnose-fucose polysaccharide. Patients with A. actinomycetemcomitans-associated periodontitis had higher antibody titers to the purified 37-kDa protein than healthy subjects (p < 0.001). Anti-37-kDa protein antibodies recognized a 37-kDa band in the cytosolic, ribosomal, and total membrane fractions from Y4 cells. Extracellular substances from other strains of A. actinomycetemcomitans (serotypes a and c) also reacted in the Western blots, but Haemophilus spp. or several periodontopathic bacteria did not. These results suggested that the 37-kDa protein is a cytosolic protein that is passed through the cell membrane, and its protein portion is specific for A. actinomycetemcomitans but common to serotypes. This protein induced Il-1 beta, Il-6, and TNF-alpha release from murine macrophages. The Il-6-inducing activity of the 37-kDa protein was higher than that of LPS. These findings suggested that the 37-kDa protein which is released from live cells plays a role in A. actinomycetemcomitans-associated periodontitis, as antigen inducing the release of inflammatory cytokines which are associated with alveolar bone loss.  相似文献   

6.
The gene encoding an outer membrane protein A (OmpA)-like, heat-modifiable Omp of Actinobacillus actinomycetemcomitans ATCC 43718 (strain Y4, serotype b) was cloned by a PCR cloning procedure. DNA sequence analysis revealed that the gene encodes a protein of 346 amino acid residues with a molecular mass of 36.9 kDa. The protein expressed by the cloned gene reacted with a monoclonal antibody to the previously described 29-kDa Omp (Omp29) of strain Y4. This monoclonal antibody reacted specifically with Omp29 of A. actinomycetemcomitans (serotype b), but not with any Omp of Escherichia coli, including OmpA. This protein exhibited characteristic heat modifiability on sodium dodecyl sulfate-polyacrylamide gels, showing an apparent molecular mass of 29 kDa when unheated and a mass of 34 kDa when heated. The N-terminal amino acid sequence of the protein expressed in E. coli perfectly matched those deduced from the purified Omp29 of strain Y4. The deduced amino acid sequence of the gene coding for Omp29 from serotype b matched completely (except for valine at position 321) that of a recently reported omp34 gene described for A. actinomycetemcomitans serotype c (NCTC 9710). Because of the conserved nature of the gene within these serotypes, we designated the gene described herein from serotype b as omp34.  相似文献   

7.
Enteric pathogens harbor a set of enzymes (e.g., superoxide dismutases [SOD]) for detoxification of endogenous and exogenous reactive oxygen species which are encountered during infection. To analyze the role of the Mn-cofactored SOD (SodA) in the pathogenicity of yersiniae, we cloned the sodA gene of Yersinia enterocolitica serotype O8 by complementation of an Escherichia coli sodA sodB mutant and subsequently constructed an isogenic mutant by allelic exchange. Sequence analysis revealed an open reading frame that enabled the deduction of a sequence of 207 amino acids with 85% identity to SodA of E. coli. In a mouse infection model, the sodA null mutant was strongly attenuated in comparison to its parental strain. After intravenous infection, the survival and multiplication of the mutant in the spleen and liver were markedly reduced. In contrast, inactivation of sodA had only minor effects on survival and multiplication in the gut and Peyer's patches, as could be demonstrated in the orogastric infection model. The reduction in virulence was accompanied by a low but significant increase of susceptibility of the soda mutant to bacterial killing by polymorphonuclear leukocytes (PMN) and an alteration of the intracellular chemiluminescence response of PMN. These results suggest that the resistance of Y. enterocolitica to exogenous oxygen radicals produced by phagocytes involves the Mn-cofactored SOD. The important role of sodA for the pathogenicity of Y. enterocolitica could also be due to detoxification of endogenous, metabolically produced oxygen radicals which are encountered by extracellular enteric pathogens during the invasion of the host.  相似文献   

8.
A simple flow cytometric method was used to study simultaneously the phagocytosis of Streptococcus suis serotype 2 by polymorphonuclear and mononuclear blood leukocytes from swine and humans. Using this method with a bacteria-to-leukocytes ratio of 10:1 and after 60 min of incubation, 80.2 +/- 2.8% of swine granulocytes and 77.0 +/- 2.8% of swine monocytes were shown to contain FITC-labelled S. suis serotype 2 strain 735. Using the same strain, FITC-labelled bacteria were found in 95.5 +/- 3.2% of human granulocytes and in 92.8 +/- 3.6% of human monocytes. The phagocytosis rates of avirulent and virulent strains of S. suis were not significantly different.  相似文献   

9.
S19 ribosomal protein is a component of the protein-producing machinery, ribosome. When recombinant S19 proteins were cross-linked intermolecularly by plasma transglutaminase (coagulation factor XIIIa), this homodimer newly exhibited monocyte chemotactic activity. This effect was specific to monocytes. The S19 protein homodimer shared the immunoreactivity with the complement-derived chemotactic factor, component 5a (C5a). Monocytes pretreated with an anti-C5a receptor antibody or with a synthetic C5a receptor antagonist responded poorly in chemotaxis to this homodimer. These data indicate that the S19 protein homodimer possesses a 3-dimensional structure similar to C5a in terms of the immunologic epitope and the receptor ligand, although homology between their primary structures is only 4%. In contrast, the S19 protein homodimer did not attract polymorphonuclear leukocytes. In addition, the homodimer inhibited a chemotactic response of polymorphonuclear leukocytes to C5a in vitro and in vivo as a receptor antagonist. Furthermore, the S19 protein homodimer competitively inhibited the binding of radiolabeled C5a to polymorphonuclear leukocytes. The S19 protein homodimer with these opposite effects in the leukocyte chemotaxis seems to induce the monocyte/macrophage predominant infiltration in chronic inflammation.  相似文献   

10.
A simple semiquantitative slide test to assess the phagocytic activity of periphera polymorphonuclear leukocytes is described. Leukocytes are isolated from one drop of blood and latex particles are offered for phagocytosis. Cellular capacities and serum opsonins can be assessed separately. In the presence of pooled adult serum no defect of phagocytosis was seen in preterm and full-term newborns nor in pediatric patients with infectious or other diseases. In 4 of 7 premature newborns a definite deficiency of serum opsonins was demonstrated. In in vitro studies complement (plus possibly other heat-labile factors) promoted phagocytosis. Phagocytic rates were depressed by endotoxin and phenylbutazone.  相似文献   

11.
Heterogeneity of the lipopolysaccharide from Pseudomonas aeruginosa   总被引:1,自引:0,他引:1  
Lipopolysaccharide isolated from pseudomonas aeruginosa PAC1 and its phage-resistant mutant was degraded by mild acid hydrolysis into lipid A and three major polysaccharide-containing fractions which were separated on Sephadex G-75. The low-molecular-weight fraction contained glucose, rhamnose, heptose, galactosamine, alanine and phosphate. The higher-molecular-weight fractions consisted mainly of glucose, rhamnose and glucosamine together with amino compounds. Alkaline degradation of the lipopolysaccharide produced at least four different species each of which contained a low-molecular-weight polysaccharide similar if not identical to that produced by acid hydrolysis. Under certain growth conditions an abnormal lipopolysaccharide was produced which was defective in the low-molecular-weight polysaccharide and contained mainly high-molecular-weight material. Strains of different serotype yielded lipopolysaccharides which also exhibited heterogeneity but contained a low-molecular-weight polysaccharide similar to that obtained from strain PAC1 and PAC1R. It is suggested that each strain of P. aeruginosa may produce several lipopolysaccharides each containing a polysaccharide common to all. The relative proportions of the various lipopolysaccharides may be changed by growth conditions.  相似文献   

12.
The anti-inflammatory effects of the amide local anaesthetics lidocaine and bupivacaine were evaluated in vitro by examination of the metabolic activation and secretory responses of human polymorphonuclear granulocytes (PMNGs) and mononuclear cells. Pretreatment with lidocaine or bupivacaine had a dose-dependent inhibitory effect on PMNG luminol-amplified chemiluminescence stimulated by bovine serum albumin (BSA)/anti-BSA immune complexes (IC) or by serum-opsonized zymosan (SOZ) particles. Both lidocaine and bupivacaine inhibited the release of the inflammatory mediators leukotriene B4 (LTB4) and interleukin-1 (IL-1) evaluated by radioimmunoassay (RIA). Pretreatment of suspended PMNGs and monocytes with the anaesthetics caused a marked inhibition of LTB4 release when the cells were stimulated with SOZ. In short-term (24 h) cultures of mononuclear cells the addition of lidocaine or bupivacaine reduced, in a dose-dependent manner, the level of IL-1 detected after stimulation with lipopolysaccharide (LPS). In all three assays (chemiluminescence, LTB4 and IL-1 RIA) bupivacaine was found to be more potent than lidocaine. The present results show that amide local anaesthetics have marked suppressive effects on the metabolic activation and secretory functions of leukocytes stimulated by different agonists. Although the detailed mechanisms for these effects are not known, they may explain part of the potent anti-inflammatory actions of local anaesthetics previously described in vivo.  相似文献   

13.
The purpose of this study is to certify the importance of the fimbriae as an attachment factor of Actinobacillus actinomycetemcomitans, a human periodontopathic bacterium, and the significance of anti-fimbrial antibody function as an attachment inhibitor. Fimbrial antigen was prepared from the A. actinomycetemcomitans 310-a strain. Oligopeptides were synthesized according to the amino acid sequence of the fimbrial protein. The peptide antigen was conjugated with branched lysine polymer resin beads. The peptide antigen was suspended in PBS emulsified with incomplete Freund's adjuvant and used to immunize rabbits. A rabbit antiserum reacted with an approximately 54 kDa protein of the fimbriae protein from A. actinomycetemcomitans 310-a and with those of other fimbriated strains. This antiserum strongly inhibited the attachment of fimbriated A. actinomycetemcomitans strains to saliva-coated hydroxyapatite beads, buccal epithelial cells, and a fibroblast cell line, Gin-1. Such a synthetic fimbrial peptide antigen may be effective in inducing antibodies which inhibit adhesion and subsequent colonization by A. actinomycetemcomitans.  相似文献   

14.
OBJECTIVE: To determine if the ammonia produced by Helicobacter pylori affects the phagocytic ability of human polymorphonuclear leucocytes as measured by the oxidative burst. METHODS: Interactions between opsonized urease-positive and -negative strains of H. pylori with polymorphonuclear leucocytes were studied in two series of experiments. In the first series of experiments, concentrations from 0 to 50 mM of NH4Cl were added to polymorphonuclear leucocytes. In the second series of experiments, bacteria were pre-incubated for 1 h with urea (0 to 50 mM) before addition of phagocytes. Luminol-dependent chemiluminescence was measured every 5 min over a 50-min period. The pH was verified in each treatment. RESULTS: Inhibition of chemiluminescence, increasing with concentration, was noted in all treatments when NH4Cl was added. When urea was added to urease-positive strains, chemiluminescence was significantly reduced when compared to the urease-negative strain and the zymosan control. This effect could not be attributed to a change in pH in the experiments using NH4Cl or urea at a concentration of 5 mM and 10 mM. CONCLUSION: Ammonia generated by H. pylori may contribute to the decreased activity of polymorphonuclear leucocytes in vivo.  相似文献   

15.
JF Sweeney  AS Rosemurgy  S Wei  JY Djeu 《Canadian Metallurgical Quarterly》1993,128(1):40-5; discussion 45-6
Per protocol, adults with an Injury Severity Score of 18 or greater underwent Candida antigen titer measurements weekly. If titers were 1:4 or greater, neutrophil function against Candida albicans was determined with use of a tritiated glucose incorporation assay, and polymorphonuclear leukocytes obtained from healthy blood donors were studied concurrently for comparison. Polymorphonuclear leukocytes from healthy blood donors and injured patients with elevated titers were able to inhibit C albicans growth in a dose-dependent fashion. Polymorphonuclear leukocytes from injured patients with elevated titers had a significantly depressed ability to inhibit Calbicans growth compared with those from healthy blood donors at all effector cell-to-target cell ratios tested. Cytokine-treated polymorphonuclear leukocytes from healthy blood donors and injured patients with elevated Candida antigen titers demonstrated significantly improved anticandidal activity at all ratios of polymorphonuclear leukocytes-to-Candida. Granulocyte macrophage-colony stimulating factor was the most potent cytokine at reconstituting polymorphonuclear leukocyte function, followed by interferon gamma and interleukin 8. In conclusion, an elevated Candida antigen titer in injured adults is associated with impaired polymorphonuclear leukocyte antifungal activity. This depressed activity can be reconstituted by the addition of cytokine.  相似文献   

16.
Actinobacillus actinomycetemcomitans is frequently associated with severe periodontitis. Many periodontitis patients have elevated levels of serum IgG antibodies to A. actinomycetemcomitans, but the role of these antibodies is unknown. This study evaluated the functional capacity of anti-A. actinomycetemcomitans IgG antibody to enhance phagocytosis of A. actinomycetemcomitans by polymorphonuclear leukocytes. Chemoluminescence assays were done using sera from 64 subjects, 61 of whom had severe periodontitis; results were compared with the subject's anti-A. actinomycetemcomitans IgG titer and avidity. There was a strong correlation between chemoluminescence and antibody log titer (P < .00001) and a weak correlation between chemoluminescence and antibody avidity (P < .05). The results support the hypothesis that anti-A. actinomycetemcomitans IgG antibodies are important in promoting phagocytosis and killing of A. actinomycetemcomitans. Subjects who develop high levels of highly avid antibodies against A. actinomycetemcomitans may have greater resistance to continued or repeated infection by this pathogen.  相似文献   

17.
A water-soluble antigenic polysaccharide of high M(r) associated with the lipopolysaccharide has been isolated from phenol-water extraction of cells of Campylobacter coli serotype O:30. The polysaccharide and oligosaccharide degradation products formed on O-dephosphorylation and by periodate oxidation followed by reduction have been investigated by one- and two-dimensional 1H, 13C, and 31P NMR. It is concluded that the antigenic polysaccharide has a teichoic acid-like structure with a poly-Ribitol phosphate, [5-Ribitol-1-P]n, backbone with side chains at O-2 of O-(6-deoxy-beta-D-talo-heptopyranosyl)-(1-->4)-(2-acetylamino-2-deoxy-beta-D- glucopyranosyl) units. The structure is unusual in Gram-negative bacteria and is unique in possessing 6-deoxy-D-talo-heptose as a constituent sugar. Evidence for the relationship of the antigenic polysaccharide to the lipopolysaccharide of low M(r) is discussed.  相似文献   

18.
BACKGROUND: Interaction of Enterococcus spp. and host defense mechanisms is not well known. Opsonic requirements of Enterococcus faecalis and Enterococcus faecium to be phagocyted by human polymorphonuclear leukocytes (PMN) were evaluated. METHODS: Twenty strains (10 E. faecalis and 10 E. faecium) were studied. Phagocytosis was determined by a radiometric assay. Bacterial cells were labelled with 3H-adenine and opsonized with: a) 10% of human pool sera (HPS); b) 10% of decomplemented HPS, and c) albumin and fibronectin. RESULTS: Phagocytosis of Enterococcus spp. by PMN in the presence of HPS was significantly higher than that in the absence of opsonins. The phagocytosis of E. faecium was higher than that of E. faecalis. A strain-dependent effect of complement in the phagocytosis of Enterococcus spp. was observed. Neither albumin nor fibronectin showed an opsonic activity on Enterococcus spp. CONCLUSIONS: A great heterogeneity in the opsonic requirements of Enterococcus spp. was observed. Serum opsonins show a critical role in the phagocytosis of E. faecalis and E. faecium by PMN, this effect being more relevant with E. faecium. A strain-dependent opsonic activity of complement was observed.  相似文献   

19.
The main protective antigen of the causative agent of plague is capsular antigen F1. The preparations of this antigen isolated from Y.pestis strain EV are characterized by a high content of polysaccharide chains of endotoxins. This can be avoided by using R-variants of bacteria as producers. In this work the comparative study of the preparations of antigen F1 obtained from Y.pestis strain EV, Escherichia coli producer strain HB101 pFS1 with the complete structure of LPS and Salmonella minnesota producer strain Re595 pFS1 with maximally reduced LPS has been made. As revealed in this study, the physico-chemical properties of these preparations (the isoelectric point, electrophoretic mobility, the molecular weight of subunits) are identical. The preparation of antigen F1 obtained from S.minnesota has been found to give the highest yield and to have the lowest content of polysaccharide admixtures. This preparation has proved to possess the maximal protective potency, which may be linked with the adjuvant and immunogenic activity of microadmixtures of glycolipid Re, contained in F1.  相似文献   

20.
Periodontitis resulting from Papillon-Lefèvre Syndrome has been known to cause early loss of primary dentition with subsequent involvement of the permanent dentition. In this study, two Papillon-Lefèvre Syndrome patients were followed for 3 years after initial treatment and improvement of their periodontal condition. In addition, two new cases of Papillon-Lefèvre Syndrome are presented. The follow-up treatment of the first two patients included monitoring the oral hygiene and performing ultrasonic scaling. Their present clinical appearance is very satisfactory. The periodontal condition of the third (new) patient was brought under control by extracting the involved deciduous teeth under antibiotic coverage, and by scaling and root planing the already erupted permanent teeth as well as by maintaining a high standard of oral hygiene. In the fourth case, all permanent teeth had erupted and the periodontium had already been severely destroyed. Actinobacillus actinomycetemcomitans was not detected by microbiologic examination after the periodontal conditions improved, except in the fourth case. Western blot analysis showed that the three first three patients had positive antibody response to the same antigens of Actinobacillus actinomycetemcomitans. Phagocytosis by polymorphonuclear neutrophil leukocytes) had not decreased, but the expression of surface receptors of polymorphonuclear neutrophil leukocytes was within the normal limits.  相似文献   

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