Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The specificity by which Haemophilus species acquired iron from transferrin (TF) was investigated. In a plate bioassay H. influenzae used iron bound to human, bovine and rabbit TFs but not mouse, rat, dog, horse, guinea-pig, pig or ovo- TFs or human and bovine lactoferrins. In contrast, H. pleuropneumoniae used iron only from pig TF whilst H. parainfluenzae was unable to utilize iron bound to any of the human or animal TFs tested. The inhibition of growth imposed on H. influenzae type b strain Eagan by the addition of the synthetic iron chelator EDDA to the culture medium was reversed by 30% iron-saturated human TF added directly to the medium but not when the TF was contained inside a dialysis bag. Dot-blotting of whole cells revealed that human TF bound to the surface of bacteria cultured in iron-restricted but not in iron-plentiful media. Incubation of whole bacterial cells in the presence of the proteolytic enzyme trypsin also abolished TF-binding activity, suggesting that the TF receptor was a protein. In competition dot blotting experiments, human and bovine but not rabbit, dog, mouse or guinea-pig TFs blocked the binding of a horseradish peroxidase--human TF conjugate. SDS-PAGE and Western blotting of outer membranes revealed the presence of a TF-binding protein of approximately 72 kDa. These results suggest that the acquisition of TF-bound iron by H. influenzae type b probably involves a direct interaction with an outer-membrane protein which shows some TF-species specificity.
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PMID:Siderophore-independent acquisition of transferrin-bound iron by Haemophilus influenzae type b. 214 16

The ability of Haemophilus influenzae, H. parainfluenzae and H. paraphrophilus to utilize iron complexes, iron-proteins and exogenous microbial siderophores was evaluated. In a plate bioassay, all three species used not only ferric nitrate but also the iron chelates ferric citrate, ferric nitrilotriacetate and ferric 2,3-dihydroxybenzoate. Each Haemophilus species examined also used haemin, haemoglobin and haem-albumin as iron sources although only H. influenzae could acquire iron from transferrin or from haemoglobin complexed with haptoglobin. None of the haemophili obtained iron from ferritin or lactoferrin or from the microbial siderophores aerobactin or desferrioxamine B. However, the phenolate siderophore enterobactin supplied iron to both H. parainfluenzae and H. paraphrophilus, and DNA isolated from both organisms hybridized with a DNA probe prepared from the Escherichia coli ferric enterobactin receptor gene fepA. In addition, a monospecific polyclonal antiserum raised against the E. coli 81 kDa ferric enterobactin receptor (FepA) recognized an iron-repressible outer membrane protein (OMP) in H. parainfluenzae of between 80 and 82 kDa (depending on the strain). This anti-FepA serum did not cross-react with any of the OMPs of H. paraphrophilus or H. influenzae. The OMPs of each Haemophilus species were also probed with antisera raised against the 74 kDa Cir or 74 kDa IutA (aerobactin receptor) proteins of E. coli. Apart from one H. parainfluenzae strain (NCTC 10665), in which an OMP of about 80 kDa cross-reacted with the anti-IutA sera, no cross-reactivity was observed between Cir, IutA and the OMPs of H. influenzae, H. parainfluenzae or H. paraphrophilus.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Utilization of enterobactin and other exogenous iron sources by Haemophilus influenzae, H. parainfluenzae and H. paraphrophilus. 215 Apr 14

Nine clinical isolates of Haemophilus somnus were screened for their ability to use different transferrins as a source of iron growth. All nine strains were capable of using bovine but not porcine, human or chicken transferrin. A screening assay for siderophore production did not show any evidence of siderophore production by these strains. When iron-deficient cells from these strains were screened for their ability to bind peroxidase-conjugated transferrin, binding was detected with conjugated bovine, but not human or porcine transferrin. Competition binding studies demonstrated that the binding of peroxidase-conjugated bovine transferrin was competitively inhibited by unconjugated bovine transferrin but not transferrin from other species. The induction of receptor expression by low iron conditions was inhibited by chloramphenicol and rifampicin but not ampicillin indicating that new protein and mRNA synthesis was required for expression of receptor activity. Affinity isolation of receptor proteins with biotinylated bovine transferrin, but not human or porcine transferrin, yielded three proteins from H. somnus strain H74. Two of the proteins were identified as 105 kDa and 73 kDa iron-regulated outer membrane proteins. A third protein of 85 kDa that was isolated did not co-migrate with any iron-regulated outer membrane protein. Affinity isolation of receptor proteins from other strains of H. somnus yielded a 73 kDa protein from all strains and a 105 kDa and 85 kDa protein in four of the six strains analysed.
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PMID:Response of Haemophilus somnus to iron limitation: expression and identification of a bovine-specific transferrin receptor. 215 61

An Escherichia coli clone producing a high-molecular-weight surface antigen of Haemophilus influenzae type b (Hib) was isolated from a library of Hib DNA fragments cloned as lysogens in a lambda replacement vector. The antigen is found in sarcosyl-insoluble outer membrane protein preparations and was produced by all 36 H. influenzae isolates tested. Absorption studies indicated that the antigen is a surface determinant on all isolates tested. Antibodies to the antigen (D15) were found in eight of nine convalescent-phase sera from children with invasive Hib infection. Affinity-purified antibodies prepared against the cloned antigen gave protection against the development of bacteremia in a rat pup model.
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PMID:Expression in Escherichia coli of a high-molecular-weight protective surface antigen found in nontypeable and type b Haemophilus influenzae. 218 12

We compared outer membrane protein (OMP) patterns of Haemophilus influenzae isolated in metropolitan Atlanta, Ga., from July 1983 to June 1985. Of 74 randomly selected H. influenzae serotype b, biotype I, isolates (24% of the total number of H. influenzae, and 32% of the total number of H. influenzae serotype b, biotype I, isolates), 66 (89.2%) had the same OMP pattern. Of the remaining eight, five (6.7%) had an identical OMP pattern. The other three isolates had separate and distinct patterns. A greater diversity of OMP patterns was found with H. influenzae serotype b, biotype II, and nonserotypeable H. influenzae. Of the 18 H. influenzae serotype b, biotype II, isolates (5.8% of the total number of H. influenzae isolates), 1 had an OMP pattern similar to that of the predominate biotype I OMP type, 6 (33% of the biotype II) had the same pattern, and 11 had heterogeneous patterns. Of the 19 recoverable, nonserotypeable biotype II isolates (6.8% of the total number of H. influenzae), 18 had different OMP patterns, and no pattern was similar to those observed with serotype b. These findings indicate that most H. influenzae strains isolated during this 2-year period were indistinguishable by serotype, biotype, or OMP patterns.
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PMID:Major subtypes of invasive Haemophilus influenzae from 1983 to 1985 in Atlanta, Ga. 219 Oct 7

Haemophilus influenzae type b is a major cause of bacterial meningitis and other invasive diseases in children under four years of age. One surface antigen, the type b capsular polysaccharide, polyribosylribitol phosphate (PRP), is a primary virulence factor of the organism. Antibody directed against PRP is protective; however, the purified polysaccharide is poorly immunogenic in young children. Polysaccharide-protein conjugate vaccines have been prepared which are significantly more immunogenic and efficacious in young children compared to the plain polysaccharide vaccine. Noncapsular surface antigens may also play a role in the virulence of H. influenzae. Some mutants (or phase variants) which differ in lipooligosaccharide (LOS) structure exhibit decreased virulence in the infant rat model of bacteremia. Proteins including the IgA protease, pili, a 98K outer membrane protein (OMP) as well as OMPs P1, P2 and P6 have also been examined in considerable detail, but whether they have a role in the virulence of the organism remains to be determined. However, antibody directed against the 98K OMP as well as P1, P2 and P6 is protective in the infant rat model of bacteremia. The role of antibody directed against LOS epitopes in protection is less clear, due at least in part, to phase variation in LOS antigens. Characterization of one surface antigen of H. influenzae type b, the capsular polysaccharide, already has led to the prevention of many cases of Haemophilus disease. Characterization of the noncapsular antigens together with a more detailed understanding of the mechanisms of virulence, most likely will permit development of even better vaccines, and possibly better treatment modalities, in the future.
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PMID:Haemophilus influenzae: surface antigens and aspects of virulence. 219 7

Haemophilus influenzae is a gram-negative rod, causing severe infections in childhood, including meningitis, sepsis, epiglottits, pneumonia and otitis. Most of the invasive infections are due to serotype b. Since ampicillin-resistance is increasing, modern cephalosporines like cefotaxime and ceftriaxone are the antibiotics of choice in severe disease. Bacterial meningitis due to Haemophilus influenzae and epiglottitis are both still life-threatening diseases with a lethality of 5% to 25%, and there are severe sequelae in 35% of meningitis cases. Efforts have been made to develop efficacious vaccines. While immunogenicity of type b polysaccharide was low in the high-risk age (below 18 months), conjugated vaccines with either diphtheria-toxoid or Neisseria meningitis outer membrane protein and the Hib polysaccharide were found to be strongly immunogenic even in the first months of life. These vaccines show every few side-effects and can easily be combined with other immunizations such as DPT and DT. Thus, the incidence of invasive infections due to Haemophilus influenzae type b might decline in future.
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PMID:[Haemophilus influenzae type B. Disease and prevention]. 219 58

The outer membrane protein composition of Haemophilus influenzae grown under a variety of culture conditions including growth in sputum and serum, and intraperitoneally in rats was analyzed. The pattern of the major outer membrane proteins, a, b,c, d, e and P6 remained very similar under all these conditions. Outer membrane proteins expressed during iron limitation were also expressed in bacteria growing in rats, in serum or in sputum. To determine the expression of the major outer membrane proteins and lipopolysaccharide in patient materials (sputum, cerebrospinal fluid, postmortem tissue) monoclonal antibodies specific for the outer membrane proteins a, b,c, d and P6 as well as lipopolysaccharide were used in immunoblotting. They showed the same reaction patterns with bacteria in the patient materials as with the bacteria isolated from these specimens. We conclude that the major outer membrane components expressed under in vitro conditions are also expressed in various clinical materials during infection.
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PMID:In vivo and in vitro expression of outer membrane components of Haemophilus influenzae. 220 Sep 43

The affinities of IgG antibodies to Haemophilus influenzae b capsular polysaccharide (polyribosyl ribitol phosphate [PRP]) elicited 1 month after immunization of 47 infants 2-greater than 18 months of age with a PRP-outer membrane protein conjugate (PRP-OMP) were measured by ELISA. Thirty-four sera had affinities distributed normally about a logarithmic mean of 3.2 x 10(5) l/mol, but 13 samples had undetectable affinities (less than 10(4) l/mol). Median affinities of sera from children 2-6 (1.5 x 10(5) l/mol) and 7-11 months of age (1.6 x 10(5) l/mol) were significantly greater than the median affinities of sera from infants 12-18 (1.8 x 10(4) l/mol) or greater than 18 months of age (4.2 x 10(4) l/mol). Sera from children greater than 18 months of age vaccinated with PRP conjugated to diphtheria toxoid had a median affinity of 6.1 x 10(4) l/mol, equivalent to that of the same age group vaccinated with PRP-OMP. Children vaccinated with PRP conjugate vaccines may produce antibodies of very low affinity, a finding that may have significance for protection from invasive disease.
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PMID:Antibody affinity in infants after immunization with conjugated capsular polysaccharide from Haemophilus influenzae type b. 223 Feb 42

A prospective nationwide surveillance of invasive Haemophilus influenzae type b disease among adults (greater than or equal to 16 years old) was conducted in Finland during 1985 through 1988. Thirty-one cases were identified (annual incidence, 0.22/100,000). Of these infections, 71% occurred in patients with severe underlying conditions. The overall case fatality rate was 26%. Septicemia (13 patients) and pneumonia (seven patients) were the most common clinical manifestations of H influenzae type b infection; the others were epiglottitis (six patients), meningitis (three patients), and arthritis (two patients). Epiglottitis occurred in significantly younger patients, all of whom were women and four of whom were previously healthy. Subtyping of the H influenzae type b isolates according to the major outer membrane protein subtype, biotype, and lipopolysaccharide serotype showed that patterns that were uncommon (14%) among children were more common (27%) in the adults.
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PMID:Spectrum of invasive Haemophilus influenzae type b disease in adults. 224 74


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