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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The composition of lipooligosaccharide (LOS) can modify the virulence of Haemophilus influenzae type b (Hib). A genomic library of Hib strain A2 was constructed in the lambda bacteriophage EMBL3. Twenty-six phage clones expressed a Hib LOS oligosaccharide epitope in Escherichia coli that was detected by the monoclonal antibody (MAb) 6E4. None of the clones bound a polyclonal sera specific for Hib A2 LOS or an anti-H. influenzae lipid A MAb. One clone, designated EMBLOS-1, assembled an oligosaccharide with an apparent molecular weight of 1,400 (the 1.4K oligosaccharide) on a 4.1K lipopolysaccharide (LPS) species in E. coli LE392 and produced a novel 5.5K LPS that bound 6E4. Binding of 6E4 to the 5.5K EMBLOS-1 LPS band was abolished by treatment with sodium metaperiodate but was not affected by digestion with proteinase K, confirming the carbohydrate nature of the epitope. The EMBLOS-1 Haemophilus insert hybridized to similar restriction fragments in type b and nontypeable strains regardless of whether they expressed the 6E4 epitope. The 6E4 epitope did not undergo phase variation in Hib strain A2 at a frequency of greater than 10(-3). The oligosaccharide of the Salmonella minnesota Re mutant and 2-keto-3-deoxyoctulosonic acid (KDO) inhibited binding of 6E4 to Hib A2 LOS. We conclude that a gene(s) encoding an enzyme(s) that assembles a stable Hib LOS epitope containing KDO is conserved in H. influenzae and that the cloned Hib LOS synthesis gene products assemble a Hib LOS epitope on an E. coli K-12 LPS core.
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PMID:Cloning and expression in Escherichia coli of a Haemophilus influenzae type b lipooligosaccharide synthesis gene(s) that encodes a 2-keto-3-deoxyoctulosonic acid epitope. 169 6

Haemophilus influenzae and its extracellular products (EP) did not release histamine in leukocyte suspensions from normal individuals. However, the EP were found to enhance basophil histamine release triggered by anti-IgE and by the calcium ionophore A23187. Experiments with EP indicate that it is the content of endotoxins which is responsible for the potentiating effect. Removal of endotoxin from the EP thus completely abolished the potentiating effect, whereas inactivation of its protease and proteins by heat-treatment or by proteinase K did not change the potentiation. A reinforcement of mediator release by the extracellular products of H. influenzae might play a pathophysiological role in chronic obstructive pulmonary disease.
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PMID:Haemophilus influenzae potentiates basophil histamine release possibly by its endotoxins. 169 61

The immunogenic and protective potentials of an outer membrane-enriched fraction (OM) from a serotype 5 strain of Actinobacillus (Haemophilus) pleuropneumoniae (APP) and the same OM degraded with proteinase K or periodate were evaluated in swine. Groups of pigs were vaccinated with two doses of OM, proteinase K-treated OM (P-OM), periodate-treated OM (PI-OM), or placebo vaccine and challenged intranasally with the homologous strain of APP. Results from triplicate experiments indicated that proteinase K treatment of OM resulted in an improved efficacy. This improved efficacy of P-OM vaccine over untreated OM vaccine was evidenced not only by less severe lung lesions in P-OM vaccinated pigs but also by significant reduction (P less than 0.05) in the number of P-OM vaccinated pigs which developed lung lesions upon challenge with APP. Assessment of sera from vaccinated animals by immunoblotting, complement fixation test, or ELISA indicated that the immunogenicity of some but not all protein or carbohydrate components were reduced (or eliminated) by proteinase K and periodate treatments respectively.
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PMID:Improved protection of swine from pleuropneumonia by vaccination with proteinase K-treated outer membrane of Actinobacillus (Haemophilus) pleuropneumoniae. 204 82

Monoclonal antibodies (MAbs) directed against epitopes in the oligosaccharide portion of the lipooligosaccharide (LOS) of nontypable Haemophilus influenzae (NTHI) were used to characterize the LOS of this pathogen. Western blot (immunoblot) analysis with four LOS-specific MAbs and proteinase K-derived LOS preparations from 69 NTHI strains allowed the classification of these strains into nine LOS antigenic groups. The use of these MAbs in a more sensitive colony blot radioimmunoassay system together with these same NTHI strains identified 14 LOS antigenic groups. Extensive cross-reactivity was detected between the LOS epitopes of these NTHI strains and the LOS of H. influenzae type b. The epitopes recognized by these MAbs were not accessible to antibody on the surface of every strain. These LOS epitopes were also not stably expressed by NTHI growing in vitro; the observed frequency of LOS antigen variation ranged from 1 to 24% when large numbers of colonies of NTHI strains were screened for reactivity with the LOS-directed MAbs in the colony blot radioimmunoassay. This LOS antigenic variation was sometimes associated with alterations in the profile of the LOS molecule as resolved by dodecyl sulfate-polyacrylamide gradient gel electrophoresis followed by staining with silver. These data indicate that considerable antigenic diversity exists among NTHI strains with regard to the oligosaccharide epitopes in their LOS molecules.
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PMID:Antigenic characterization of the oligosaccharide portion of the lipooligosaccharide of nontypable Haemophilus influenzae. 244 82

We previously demonstrated that pneumococcal extracts contain a highly specific inhibitor of human neutrophil elastase (HNE). We now show that the active inhibitor in these extracts is a high-molecular-weight, heat-stable substance that appears to be RNA, since inhibitory activity of pneumococcal extracts is decreased by incubation with ribonuclease but not by incubation with deoxyribonuclease or proteinase K. Moreover, metabolically labeled ([3H]uridine) pneumococcal RNA, isolated by phenol extraction followed by ethanol precipitation, strongly inhibits HNE. Pneumococcal capsular polysaccharide, although polyanionic, is only weakly inhibitory toward HNE and is not a major source of elastase-inhibitory activity in pneumococcal extracts. On the other hand, the capsule of Haemophilus influenzae type b contains polyribosylribitol phosphate. This highly charged polyanion possesses HNE-inhibitory activity, but only under special circumstances to be discussed below. Pneumococci (type I, type II smooth, type II rough) and H. influenzae (type b) all release HNE-inhibitory activity into their culture medium during growth. By contrast, Klebsiella pneumoniae and Staphylococcus aureus release little (if any) stable HNE-inhibitory activity during growth. We propose that some bacterial pneumonias may spare host tissue because polyanions released by the invading microorganisms (e.g. RNA from autolysing pneumococci) inhibit elastase released from inflammatory neutrophils and thereby modulate accompanying tissue proteolysis. Pneumonias caused by microorganisms that do not release stable polyanionic inhibitors of HNE (e.g., Staphylococcus and Klebsiella) may be correspondingly more injurious to the lung.
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PMID:Inhibition of human neutrophil elastase by bacterial polyanions. 244 47

Isolates of Haemophilus influenzae type b (Hib) can be divided into three antigenic groups based on their reactivities with a set of two monoclonal antibodies (MAbs) directed against epitopes in the oligosaccharide region of Hib lipooligosaccharide (LOS) (P. A. Gulig, C. C. Patrick, L. Hermanstorfer, G. H. McCracken, Jr., and E. J. Hansen, Infect. Immun. 55:513-520, 1987). Approximately 24% of Hib strains react with both of these LOS-specific MAbs. Immunoprecipitation experiments involving several of these strains indicated that the epitopes recognized by these MAbs resided in two different LOS molecules, both of which were synthesized by these particular Hib strains. In addition, Western blot (immunoblot) analysis of proteinase K-treated cell extracts of these strains that had been subjected to sodium dodecyl sulfate-polyacrylamide gradient gel electrophoresis revealed two different LOS staining patterns when they were probed independently with the two MAbs. Colony blot radioimmunoassay of hundreds of colonies of one of these Hib strains showed that each colony bound both MAbs. Immune electron microscopy confirmed that individual cells of this same Hib strain expressed both types of LOS molecule at the same time. An antibody accessibility radioimmunoassay was used to show that different Hib strains of this type varied in the relative amounts of each of the two MAbs that they could bind to their cell surfaces. These findings indicate that some Hib strains can synthesize two antigenically distinct LOS molecules simultaneously.
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PMID:Antigenic evidence for simultaneous expression of two different lipooligosaccharides by some strains of Haemophilus influenzae type b. 278 4

The techniques of capsular serotype, biotype determination and sodium dodecylsulphate polyacrylamide gel electrophoresis of sarcosinate-insoluble outer membrane protein (OMP) and of proteinase K lipopolysaccharide (LPS) preparations were applied to 41 genital and neonatal Haemophilus influenzae isolates. Twelve percent were capsulated (4b, 1a). Distribution of strains between biotypes was similar to that of isolates of other non-systemic pathogenic origin; only one isolate was biotype IV. The OMP profiles showed great variability with 4 group of proteins: a 16-Kd major peptide which was observed in all strains; 27-30-Kd major OMP including one constant 30-Kd peptide present in all strains except one; 32- to 50-Kd major OMP; and 49- to 54-Kd minor OMP. The rough LPS profiles also revealed heterogeneity. In view of the variability observed among H. influenzae strains, it is not possible to establish a relationship between pathogenicity and a macromolecular marker.
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PMID:[Heterogeneity of strains of Haemophilus influenzae of genital and neonatal origin: analysis of capsular serotypes, biotypes and electrophoretic profiles of external membrane proteins and LPS]. 350 Jul 32

Sera from pigs infected with Haemophilus (Actinobacillus) pleuropneumoniae were tested for antibodies to outer membrane proteins (OMPs) of the organism by immunoblotting. Convalescent sera were produced in naturally born, colostrum-fed pigs and in cesarean-derived, colostrum-deprived pigs given H. pleuropneumoniae serotype 5 intranasally twice at 5-week intervals. Sera, collected at weekly intervals, were reacted with Sarkosyl-insoluble, OMP-enriched preparations of H. pleuropneumoniae which had been separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electrophoretically transferred to nitrocellulose. Antibodies were detected to OMPs with an apparent molecular weight of 16,500 (16.5K OMP); to 29K, 38.5K, 43.5K, 45K, 49.5K, and 66.5K OMPs; and to several high-molecular-weight (greater than or equal to 94,000) OMPs, but not to the major 42K OMP. Antibodies to the heat-modifiable OMP (29K/43.5K) and the 38.5K OMP were detected in sera from noninfected pigs. Antibodies were also detected to two broad 54,000- and 95,000-molecular-weight bands which did not stain with Coomassie blue, stained with silver nitrate, resisted proteinase K digestion, and were eliminated by oxidation with sodium metaperiodate. This indicates that the 54,000- and 95,000-molecular-weight bands represent polysaccharide, possibly capsular or lipopolysaccharide immunogens. Adsorption of sera with cells from the homologous serotype 5 strain removed antibodies to the 45K, 49.5K, 66.5K, and greater than or equal to 94K OMPs and to the two polysaccharide bands, indicating that these antibodies were directed primarily to surface-exposed epitopes. When tested with OMP preparations from other serotype 5 strains, heterogeneity was apparent, both in the reactions with OMPs and with the polysaccharide bands. Silver staining of proteinase K-treated, whole-cell lysates from serotype 5 strains also indicated variable expression of the polysaccharide bands. Sera also reacted with OMPs from H. pleuropneumoniae serotypes 1 and 7; however, several OMPs and the lipopolysaccharide or polysaccharide determinants of these serotypes appeared to be type specific.
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PMID:Antibody response of swine to outer membrane components of Haemophilus pleuropneumoniae during infection. 353 48

The lipooligosaccharides (LOS) of nontypable Haemophilus influenzae are an antigenically heterogeneous group of macromolecules. Immunodiffusion and enzyme-linked immunosorbent assay inhibition studies with phenol-water-extracted LOS and absorbed antisera specific for the oligosaccharide portion of the LOS identified six LOS strain-specific antigens. To facilitate screening large numbers of strains to search for LOS antigenic heterogeneity, a system utilizing proteinase K whole cell digests in Western blots was developed. Seventy-two nontypable H. influenzae LOS extracts were analyzed in this Western blot assay. Thirty-seven of these extracts could be segregated into 10 antigenically distinct LOS groups based on immunologic recognition by one or more of the rabbit antisera. Thirty-five of the strains did not contain these LOS antigens. These results demonstrate that antigenic differences exist among the LOS of nontypable H. influenzae strains, and this heterogeneity has the potential to be used to establish an LOS-based serogrouping system.
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PMID:Antigenic diversity of lipooligosaccharides of nontypable Haemophilus influenzae. 354 63

A serotyping system for nontypable Haemophilus influenzae (NTHI) was developed by using isolated outer membrane protein (OMP) preparations and rabbit antisera. OMPs of 23 strains were isolated by molecular sieve chromatography of outer membranes in 1.5% sodium deoxycholate buffer. These OMP preparations were relatively free of lipopolysaccharide as determined by silver staining of sodium dodecyl sulfate gels and by dot assay with a monoclonal antibody which is specific for the lipid A of H. influenzae. Three antisera raised to whole organisms were used to serotype 21 of 23 strains with a kinetic enzyme-linked immunosorbent assay. Digestion of OMP preparations with proteinase K removed greater than 90% of the antigenic reactivity, indicating that the system is based on OMP antigens. Marked antigenic heterogeneity of OMPs exists among strains of NTHI. By determining the pattern of serological reactivity of OMPs with the three antisera, isolates were divided into groups based on antigenic differences. Six serotypes were identified. This OMP serotyping system is based on multiple antigenic determinants. Future studies will focus on identifying serotype-specific epitopes to further refine this serological classification scheme for NTHI.
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PMID:Antigenic heterogeneity of outer membrane proteins of nontypable Haemophilus influenzae is a basis for a serotyping system. 387 83


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