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)

In an attempt to establish if cross protection can be induced by different strains of Haemophilus parasuis, three groups of 12 gnotobiotic pigs were immunized each with an aluminum hydroxide adsorbed whole cell bacterin of one of three H. parasuis strains. Two weeks later, four pigs within each vaccinated group were challenged with aerosols of live cultures of each of the three test strains and observed for response. Two virulent strains V1 and V2 protected all the vaccinated pigs, while all nonvaccinated controls succumbed to Glasser's disease when challenged with these strains. Vaccination with strain LV (of low virulence) protected the pigs against challenge with strain V2, but not against strain V1. Strain LV did not cause disease in the immunized animals and only in one of ten nonimmunized pigs upon second challenge. The results suggest that strains may differ in antigenicity and that virulence and immunoprotection are positively related. Strains to be used in commercial vaccines should therefore be selected carefully. Antibodies detected in the sera of vaccinated pigs were to outer membrane proteins of the bacteria, but not to lipopolysaccharides or capsular polysaccharides. This would suggest that for gnotobiotic pigs outer membrane proteins are more immunogenic than lipopolysaccharide or capsular antigens. Further work is needed to determine if outer membrane proteins also contribute protective immunogens.
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PMID:Cross protection among Haemophilus parasuis strains in immunized gnotobiotic pigs. 188 82

The cytotoxicity of purified lipopolysaccharide (LPS) from a prototype Haemophilus influenzae type b (Hib) strain (Eagan) and three transformants, differing in their LPS phenotype, for bovine aortal endothelial cells (BAOEC) was investigated. All LPS preparations caused cell disruption and release of lactate dehydrogenase (LDH), an indicator of cytotoxicity, from BAOEC monolayers but to differing extents. There was no correlation between the cytotoxicity of purified Hib LPS to BAOEC monolayers and potential to cause bacteraemia in experimental animals.
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PMID:In vitro cytotoxicity of Haemophilus influenzae lipopolysaccharides for bovine aortal endothelial cells. 188 91

Recurrent and chronic pulmonary infection is still the major cause of morbidity and mortality in cystic fibrosis. Although respiratory viruses are responsible for some of the acute exacerbations of the pulmonary disease, bacteria, and in some patients Aspergillus fumigatus, are the most important pathogens. Staphylococcus aureus and Haemophilus influenzae are the most prevalent pathogens in cystic fibrosis of childhood, whereas Pseudomonas aeruginosa and in some centres also Pseudomonas cepacia predominate in older children and adult patients. The chronic Pseudomonas aeruginosa infection is peculiar, since it is predominantly an endobronchial infection in small bronchioles caused by mucoid, alginate producing strains which gradually lose most of the O-antigenic determinants of the lipopolysaccharide. Although P. aeruginosa produces a number of other toxins which may play a role initially, most if not all of the pathology is caused by immune complex mediated chronic inflammation. The bacteriological results of antipseudomonas chemotherapy are disappointing, as these bacteria are virtually never permanently eliminated. The clinical results of repeated maintenance chemotherapy every 3 months are, however, good, since it is possible to preserve lung function for years and keep the patients alive. Antiinflammatory treatment with steroids for years is used in some patients with benefit.
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PMID:Cystic fibrosis: infection. 190 Jun 40

A chromosomal locus, lic3, one of several involved in lipopolysaccharide (LPS) biosynthesis by Haemophilus influenzae, was cloned and its DNA sequence determined. lic3 comprises four closely apposed open reading frames (ORFs). ORF1 includes tandem repeats of the tetramer CAAT and two start codons out of frame with each other are found upstream of the repeats. ORF1 encodes a protein with no known homologues. ORF2 encodes the UDP-galactose-4-epimerase (galE) gene. ORF3 encodes a hydrophobic protein with no known homologues. ORF4 encodes the adenylate kinase (adk) gene. A deletion/insertion mutation lacking the 3' end of ORF1, all of galE, and the 5' end of ORF3 was constructed in the parent Hib strain (RM7004). These mutants had a galE phenotype, as evidenced by galactose sensitivity, altered LPS when grown in the absence of exogenous galactose, and reduced virulence in infant rats.
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PMID:Molecular analysis of a complex locus from Haemophilus influenzae involved in phase-variable lipopolysaccharide biosynthesis. 195 82

Unidentified low-molecular-weight factor(s) in serum or nasopharyngeal secretions were known to phenotypically increase the resistance of Haemophilus influenzae type b (Hib) to bactericidal and opsonic antibodies, and resistance was attributed to two hypothetical mechanisms. Serum components generating resistance were studied. Mechanism 1, present in some Hib strains and their capsule-deficient mutants and accompanied by apparent increases in lipopolysaccharide content, was reproduced with a mixture of glucose, lactate, urea, and bicarbonate. Mechanism 2, present only in capsulated Hib and accompanied by increased capsulation, was reported with a mixture of Ca++ and lactate. Hib incubated with these compounds in buffer or grown in serum filtrate was resistant, but Hib grown in conventional media containing the metabolites in serum filtrate was resistant, but Hib grown in conventional media containing the metabolites was not. The resistant phenotype, which resembles Hib in vivo, may depend on nutrient balance as well as the specific factors. Lactate apparently is an important energy source for Hib.
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PMID:Host metabolites that phenotypically increase the resistance of Haemophilus influenzae type b to clearance mechanisms. 201 56

The phagocytosis of Haemophilus influenzae type b (Hib) by rat macrophages and the intracellular fate of ingested organisms was investigated using an acridine orange-crystal violet assay. There was a correlation between the ability of organisms to survive in macrophages in vitro and their ability to cause invasive disease. Encapsulated Hib survived and replicated within macrophages, whereas capsule-deficient mutants, although more susceptible to phagocytosis, were killed after ingestion. Differences in lipopolysaccharide also affected the ability of encapsulated Hib to survive in macrophages. The presence of viable intracellular organisms in macrophages in vivo may enhance the persistence of bacteremia and may also be important in mediating the entry of Hib into the central nervous system.
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PMID:Relationship between intracellular survival in macrophages and virulence of Haemophilus influenzae type b. 203 2

Twenty-four Haemophilus influenzae type b strains from 836 children and young adults in an open population were subtyped by outer-membrane-protein (OMP) analysis on sodium dodecyl sulphate-polyacrylamide gels, lipopolysaccharide serotyping and biotyping. The results were compared with those obtained with H. influenzae type b strains from 97 patients with meningitis in the same city (Amsterdam). OMP subtype 1 was significantly more common among the CSF isolates than in carrier strains (82% vs 50%; p less than 0.002). The other OMP subtypes found among carriers were rarely isolated from patients. The lipopolysaccharide serotype and biotype distribution did not differ between the two groups. The combination of OMP subtype 1, lipopolysaccharide 1, biotype I was much more common in isolates from patients than in those from carriers (71% vs 42%; p less than 0.01). The data suggest that various H. influenzae type b subtypes are less virulent than those commonly isolated from invasive infections.
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PMID:Differences in subtype distribution of Haemophilus influenzae type b from carriers in the general population and patients with meningitis. 205 15

Three monoclonal antibodies (MAbs) to lipopolysaccharide of Actinobacillus actinomycetemcomitans strain Y4 (serotype b) and eight MAbs to a serotype b-specific polysaccharide antigen of strain Y4 were obtained. Latex particles sensitized with an MAb to the Y4 lipopolysaccharide produced a positive agglutination with whole cells of all three serotypes of A. actinomycetemcomitans, but not with Haemophilus aphrophilus, Haemophilus paraphrophilus, Haemophilus influenzae, Porphyromonas (Bacteroides) gingivalis, "Bacteroides" intermedius, Fusobacterium nucleatum and Escherichia coli. On the other hand, latex particles sensitized with an MAb to the serotype b-specific polysaccharide antigen agglutinated with whole cells of serotype b A. actinomycetemcomitans and P. gingivalis, but not with heated and trypsinized cells of P. gingivalis. The simple and rapid latex agglutination assay using MAbs may be useful for the identification of A. actinomycetemcomitans.
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PMID:Monoclonal antibody-coated latex agglutination assay for identification of Actinobacillus actinomycetemcomitans. 212 92

The Haemophilus-Actinobacillus-Pasteurella (HAP) group of bacteria contains a number of important veterinary and human pathogens. Although each species has specific characteristics and host range, most share the general property of being resistant to cellular defense mechanisms. In some cases (e.g. Pasteurella multocida, Pasteurella haemolytica and Actinobacillus pleuropneumoniae) resistance results in part from the presence of an antiphagocytic capsule that protects the bacilli against ingestion by neutrophils and macrophages. In other instances the bacteria aggressively attack mononuclear and polymorphonuclear phagocytes. For example, P. haemolytica, A. pleuro-pneumoniae and Actinobacillus actinomycetemcomitans each produce a leukotoxin that functionally impairs, and ultimately kills, leukocytes from cattle, pigs and human beings, respectively. Components of Pasteurella multocida and Haemophilus somnus have also been reported to adversely affect leukocyte functions. Another important area of research that is just emerging concerns the ability of lipopolysaccharide and other components of HAP bacteria to stimulate or modulate macrophage release of inflammatory mediators such as interleukin-1. In this paper, we provide an overview of the interactions of HAP bacteria with phagocytes and identify some of the common strategies by which they evade cellular defenses.
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PMID:Interactions of Haemophilus-Actinobacillus-Pasteurella bacteria with phagocytic cells. 219 2

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


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