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)

Haemophilus influenzae acquires iron from the iron-transporting glycoprotein transferrin via a receptor-mediated process. This involves two outer-membrane transferrin-binding proteins (Tbps) termed Tbp1 and Tbp2 which show considerable preference for the human form of transferrin. Since the Tbps are attracting considerable attention as potential vaccine components, we used transferrin affinity chromatography to examine their conservation amongst 28 H. influenzae type b strains belonging to different outer-membrane-protein subtypes as well as six non-typable strains. Whole cells of all type b and non-typable strains examined bound human transferrin; whilst most strains possessed a Tbp1 of approximately 105 kDa, the molecular mass of Tbp2 varied from 79 to 94 kDa. Antisera raised against affinity-purified native H. influenzae Tbp1/Tbp2 receptor complex cross-reacted on Western blots with the respective Tbps of all the Haemophilus strains examined. When used to probe Neisseria meningitidis Tbps, sera from each of four mice immunized with the Haemophilus Tbp1/2 complex recognized the 68 kDa Tbp2 of N. meningitidis strain B16B6 but not the 78 kDa Tbp2 of N. meningitidis strain 70942. Serum from one mouse also reacted weakly with Tbp1 of strain B16B6. Apart from a weak reaction with the Tbp2 of a serotype 5 strain, this mouse antiserum failed to recognize the Tbps of the porcine pathogen A. pleuropneumoniae. However, a monospecific polyclonal antiserum raised against the denatured Tbp2 of Neisseria meningitidis B16B6 recognized the Tbps of all Haemophilus and Actinobacillus strains examined. Since H. influenzae forms part of the natural flora of the upper respiratory tract, human sera were screened for the presence of antibodies to the Tbps. Sera from healthy adults contained antibodies which recognized both Tbp1 and Tbp2 from H. influenzae but not N. meningitidis. Convalescent sera from meningococcal meningitis patients contained antibodies which, on Western blots, recognized the Tbps2s of both pathogens. These data demonstrate the existence of shared epitopes on the Tbps of H. influenzae, N. meningitidis and A. pleuropneumoniae despite their transferrin species specificity.
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PMID:Conservation and antigenic cross-reactivity of the transferrin-binding proteins of Haemophilus influenzae, Actinobacillus pleuropneumoniae and Neisseria meningitidis. 900 13

Haemophilus somnus is an important cause of bovine respiratory disease and septicemia with all it's sequelae. The role of immune responses in protection and immunopathogenesis is not well understood. We showed that infection with bovine respiratory syncytial virus (BRSV) 6 days before H. somnus increased clinical scores and levels of IgE antibody to H. somnus over that of infection with H. somnus alone. To determine whether antigenic specificity of IgE responses differed from IgG responses, Western blots were done with sera from the infected calves, at 0 time and at 21 days post infection. Thus each calf was its own control. IgG antibodies recognized primarily a 40 kDa outer membrane protein (OMP) in whole cell H. somnus preparations and a 270 kDa immunoglobulin binding protein (IgBPs) in culture supernatants but generally not the 41 kDa major OMP (MOMP). IgE antibodies recognized primarily the 41 kDa MOMP in whole cell pellet preparations. Results were consistent among calves. With culture supernatants, IgE antibodies recognized both the 270 kDa IgBPs and the MOMP. Since some H. somnus strains from asymptomatic carriers (including strain 129Pt), do not have IgBPs and express a truncated MOMP (33 kDa rather than 41 kDa), reaction of strain 129Pt cells with serum from calves infected with H. somnus or BRSV and H. somnus was studied. IgE did not react with the truncated MOMP even at much lower (1:100) dilutions than in Western blots with virulent strain 2336 (serum dilution of 1:500). Reactions of IgE with the 40 and 78 kDa antigens in strain 129Pt were noted but since the major reactivities with the IgBPs and the MOMP were not detected, this strain may be useful for inducing protective rather than immunopathogenic responses.
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PMID:Specificity of IgG and IgE antibody responses to Haemophilus somnus infection of calves. 1682 20