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)

A prominent 19 kDa surface antigen of Legionella pneumophila, cloned in Escherichia coli, was found to be intimately associated with peptidoglycan. The DNA region encoding this antigen was mapped on an 11.9 kb plasmid by means of deletion analysis and transposon mutagenesis. PhoA+ gene fusions, gene-rated by TnphoA insertions into this region, confirmed the presence of a gene encoding a secreted protein. PhoA+ transposon insertions were also associated with loss of the 19 kDa antigen in immunoassays using a monoclonal antibody (mAb1E9) and the replacement of the 19 kDa antigen with larger fusion proteins in immunoblots using Legionella immune serum. A 1540bp PstI fragment carrying the gene was sequenced, and the open reading frame encoding the antigen was identified. The gene encodes a polypeptide 176 amino acid residues long and 18913Da in size. The presence of a signal sequence of 22 amino acids with a consensus sequence for cleavage by signal peptidase II indicates that the antigen is a lipoprotein, and striking similarity with peptidoglycan-associated lipoproteins (PALs) from E. coli (51% amino acid homology) and Haemophilus influenzae (55% homology) is noted. We conclude that the 19kDa antigen of L. pneumophila is the structural equivalent of the PAL found in other Gram-negative species and suggest that its post-translational acylation may explain its potency as an immunogen.
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PMID:Characterization of a Legionella pneumophila gene encoding a lipoprotein antigen. 176 77

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

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

The protein P2 comprises a large proportion of the outer membrane of nontypable Haemophilus influenzae and functions as a porin. In view of the importance of the protein as a surface antigen, the present study was designed to purify and analyze P2 with particular emphasis on detection of antigenic determinants expressed on the bacterial surface and identification of bactericidal targets on P2. The P2 protein was purified by using detergent solubility, anion-exchange chromatography, and gel-filtration chromatography sequentially. Two monoclonal antibodies to P2 were developed. One antibody (2E6) recognized a determinant expressed on the bacterial surface, whereas the other antibody (3F3) recognized an internal epitope. The surface-exposed 2E6 determinant was present on 12% of strains from a nationwide collection. P2 is a bactericidal target for antibody 2E6. Cyanogen bromide cleavage of P2 resulted in two fragments, as in type b strains. Both monoclonal antibodies recognized epitopes on the larger fragment. These observations have potentially important implications regarding the development of vaccines to prevent H. influenzae infections and the development of a serotyping system for epidemiologic studies.
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PMID:Purification and analysis with monoclonal antibodies of P2, the major outer membrane protein of nontypable Haemophilus influenzae. 245 40

A micro-enzyme-linked immunosorbent assay for quantitation of immunoglobulin A-specific anti-Haemophilus influenzae antibody is described and characterized. It had a sensitivity of 27 ng/ml, which is appropriate to detect antibody levels in normal saliva. Specificity for H. influenzae was achieved with the H1H2 group of antigens. Absorption studies for a range of bacteria showed little cross-reactivity, with the exception of Pseudomonas aeruginosa. Absorption studies involving various antigen preparations obtained from H. influenzae indicated that the H1H2 antigen group included significant amounts of surface antigen. An analysis of saliva from normal subjects and patients with chronic obstructive lung disease showed significant differences in levels of antibody, highlighting the potential value of the assay.
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PMID:Development of an immunoglobulin A-specific anti-Haemophilus influenzae antibody assay for detection of antibody in human mucosal secretions. 349 46

We administered a combined preparation of hepatitis B virus (HBV) vaccine and Haemophilus influenzae type b (Hib) conjugate vaccine (meningococcal protein conjugate) to 20 healthy adult volunteers. Participants received two doses of vaccine one month apart, and had serum samples drawn each time they received the vaccine and 1 month after the second dose. In 18 of 19 persons who were positive for antibody to hepatitis B surface antigen (anti-HBs), these levels had a median fold increase of 23.4 (range 0.69 to 270) 1 month after the first dose of vaccine. Anti-HBs levels generally fell slightly one month after the second dose was given. All of the study participants initially had detectable levels of antibody to Hib capsular polysaccharide (anti-PRP), and 19 of the 20 exhibited a median fold increase of 11.2 (range 0.81 to 740) in anti-PRP 1 month after vaccination. Over half (65%) continued to demonstrate increased levels of anti-PRP with the second dose of vaccine. Most participants experienced some slight to moderate discomfort at the injection site. The results indicate that the combined Hib/HBV vaccine produces increased antibody levels in healthy adults who have previously been exposed to these two antigens.
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PMID:Safety and immunogenicity of a combined hepatitis B virus-Haemophilus influenzae type B vaccine formulation in healthy adults. 839 80

Membrane proteins of Pasteurella multocida have been shown previously to elicit protective immunity. We have identified an 87-kDa outer membrane antigen, Oma87, which is present in all 16 serotypes of P. multocida. The gene encoding this protein was cloned and sequenced and found to have significant similarity to the D15 protective surface antigen of Haemophilus influenzae. Oma87 was localized to the outer membrane of the cell, and proteinase K treatment suggested that the protein is surface exposed. Native and recombinant Oma87 were strongly immunostained by convalescent-phase antiserum, indicating that the protein is expressed in vivo. Specific Oma87 antiserum protected mice against homologous, lethal P. multocida challenge. These results suggest that Oma87 is a protective outer membrane antigen of P. multocida.
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PMID:Cloning, sequencing, expression, and protective capacity of the oma87 gene encoding the Pasteurella multocida 87-kilodalton outer membrane antigen. 875 48

A recombinant hepatitis B vaccine was administered to over 5000 infants in a prospective, randomized and blinded study. Infants were given either recombinant hepatitis B vaccine (Engerix-B, SmithKline Beecham Pharmaceuticals, 10 micrograms dose-1) or a Haemophilus influenzae type b (Hib) conjugate vaccine at 2, 4 and 6 months of age simultaneously with diphtheria-tetanus-pertussis and oral polio vaccines. Adverse reactions were ascertained by parental reports and interviews, and review of medical records. Blood specimens collected from 269 infants given hepatitis B vaccine were assayed for antibody to hepatitis B surface antigen (anti-HBs) by enzyme immunoassay. Infants given hepatitis B vaccine experienced low rates of adverse reactions that were similar or lower than the rates in infants given Hib conjugate vaccine. The geometric mean anti-HBs concentrations were 9.6 mIU ml-1 after one dose, 333 mIU ml-1 after two doses and 1812 mIU ml-1 after three doses (99% had levels > or = 10 mIU ml-1). Antibody responses to diphtheria and tetanus toxoids were unaffected by simultaneous administration of hepatitis B or Hib conjugate vaccine. Engerix-B vaccine was safe and immunogenic when given with other routine childhood immunizations at 2, 4 and 6 months of age, and should provide long-term protection against hepatitis B virus infection.
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PMID:Safety and immunogenicity of a recombinant hepatitis B vaccine administered to infants at 2, 4 and 6 months of age. The Kaiser-UCLA Vaccine Study Group. 881 29

Nontypeable Haemophilus influenzae (NTHi) is an important cause of otitis media in children and of pneumonitis in adults with depressed resistance. Lipooligosaccharide (LOS) is a major surface antigen of NTHi and elicits bactericidal and opsonic antibodies. We prepared detoxified LOS (dLOS) protein conjugates from NTHi for use as experimental vaccines. LOS from NTHi 9274 was treated with anhydrous hydrazine and had its toxicity reduced to clinically acceptable levels. dLOS was bound to tetanus toxoid (TT) or high- molecular-weight proteins (HMPs) from NTHi through a linker of adipic acid dihydrazide to form dLOS-TT or dLOS-HMP. The molar ratio of the dLOS to protein carriers ranged from 26:1 to 50:1. The antigenicity of the conjugates was similar to that of the LOS alone as determined by double immunodiffusion. Subcutaneous or intramuscular injection of the conjugates elicited a 28- to 486-fold rise in the level of immunoglobulin G antibodies in mice to the homologous LOS after two or three injections and a 169- to 243-fold rise in the level of immunoglobulin G antibodies in rabbits after two injections. The immunogenicity of the conjugates in mice and rabbits was enhanced by formulation with monophosphoryl lipid A plus trehalose dimycolate. In rabbits, conjugate-induced LOS antibodies induced complement-mediated bactericidal activity against the homologous strain 9274 and prototype strain 3189. These results indicate that a detoxified LOS-protein conjugate is a candidate vaccine for otitis media and pneumonitis caused by NTHi.
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PMID:Synthesis, characterization, and immunologic properties of detoxified lipooligosaccharide from nontypeable Haemophilus influenzae conjugated to proteins. 892 67

The role of a 76 kDa surface antigen (p76) of Haemophilus somnus in virulence was investigated. The p76 gene from a virulent isolate of H. somnus (strain 2336) was introduced into an asymptomatic carrier strain (129Pt) lacking this gene. This was accomplished by the development of a system for genetic exchange in H. somnus. The cloned p76 gene was inserted into the broad host range vector pLS88, electroporated into H. influenzae for modification and then into the H. somnus strain 129Pt. The recombinant plasmid was characterized from selected transformants and expression of the p76 protein was demonstrated by Western immunoblotting. However, transformants were not serum resistant and surface exposure of the recombinant protein could not be detected, suggesting that additional genetic elements might be required for export.
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PMID:Transformation of a virulence associated gene of Haemophilus somnus into a strain lacking the gene. 931 Nov 21


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