Binding and surface exposure characteristics of the gonococcal transferrin receptor are dependent on both transferrin-binding proteins

Cornelissen, Cynthia Nau; Sparling, P. Frederick

doi:10.1128/jb.178.5.1437-1444.1996

Cited by 116 publications

(200 citation statements)

References 59 publications

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“…Siderophoremediated iron transport is characteristically employed by pathogens such as Escbericbia coli, Klebsiella, Salmonella, Sbigella and Psezrdomonas spp. The second mechanism relies on the direct binding of transferrin to a bacterial cell surface transferrin receptor and is further distinguished from siderophore-mediated iron uptake by a marked host transferrin species specificity (Williams & Grifiths, 11-192 ;Cornelissen & Sparling, 1994). For example, the transferrin iron uptake systems of Haemopbih inflzlnaae and Neisseria meningitidis, organisms which have no natural non-human hosts, are specific for human transferrin and discriminate against other mammalian transferrins (Morton & Williams, 1989;Schryvers & Morris, 1988).…”

Section: Introductionmentioning

confidence: 99%

“…For example, Pastewella baemohtica, which can cause serious infections in cattle, sheep and goats, can sequester transferrin-bound iron from a broad range of ruminant transferrins (Ogunnariwo & Schryvers, 1990). Whilst the biochemical mechanism by which pathogenic bacteria acquire transferrin-bound iron via siderophoreindependent mechanisms has not been fully elucidated, several studies have demonstrated that the utilization of iron from transferrin requires a direct interaction between outer-membrane transferrin-binding proteins (Tbps) and the iron-binding glycoprotein (Morton & Williams, 1990 ;Holland et al, 1991 ;Irwin e t al., 1993;Gray-Owen e,t al., 1995 ;Cornelissen & Sparling, 1996). Using transferrin affinity chromatography of detergent-solubilized membranes, two Tbps (Tbpl and Tbp2) can be purified from bacteria such as H. infaenxae (Schryvers, 1989;Holland e t al., 1992), N .…”

Section: Introductionmentioning

confidence: 99%

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Conservation and antigenic cross-reactivity of the transferrin-binding proteins of Haemophilus influenzae, Actinobacillus pleuropneumoniae and Neisseria meningitidis

et al. 1996

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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 T b p l 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 nontypable strains examined bound human transferrin; whilst most strains possessed a T b p l of approximately 105 kDa, the molecular mass of Tbp2 varied from 79 to 94 kDa. Antisera raised against affinity-purified native H. influenzae TbpllTbp2 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 TbplR 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 T b p l 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 monospecif ic 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 T b p l 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. influenre, N. meningitidis and A. pleuropneumoniae despite their transferrin species specificity.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Conservation and antigenic cross-reactivity of the transferrin-binding proteins of Haemophilus influenzae, Actinobacillus pleuropneumoniae and Neisseria meningitidis

et al. 1996

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“…These data indicate that gonococci undergo an adaptive response upon exposure to stress conditions and that the regulatory system pilA/pilB seems to be involved in the induction of this response. (Biswas & Sparling, 1995;Cornelissen & Sparling, 1996).…”

Section: Analysis Of the Protein Profile In Pi/a/pi/b Mutants Comparementioning

confidence: 99%

Control of Neisseria gonorrhoeae pilin gene expression by environmental factors: involvement of the pilA/pilB regulatory genes

et al. 1997

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The control of the expression of the pilin gene (pi/€) in Neisseria gonorrhoeae under a wide variety of growth conditions has been studied. The expression of pi/€ was measured using transcriptional fusions between pi/€ and the gene encoding chloramphenicol acetyltransferase (CAT), and the level of pilin production was measured by Western blot analysis. Many of the conditions tested affected both growth rate and pilin gene expression (e.9. isoleucine, high osmolarity, high temperature, anaerobic growth, pH 6, urea and iron depletion). Changes in the level of many other proteins were also observed, depending on the conditions, indicating that gonococci undergo an adaptive response to environmental variations. Moreover, environment-induced changes in the level of many proteins, including pilin, seem to involve the pi/A/pi/B regulatory system, which has been previously proposed to modulate the expression of the gonococcal pilin gene.

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“…Numerous investigators have relied heavily on solid-phase dot blot assays to estimate receptor-ligand binding kinetics. However, Cornelissen and Sparling reported that solid-phase assays did not accurately represent the binding of ligand to live cells, perhaps because receptor conformations important for ligand binding were disrupted by the drying process (15). Therefore, we had previously developed a liquid-phase 125 I-Hb binding assay to measure the equilibrium binding kinetics of Hb to HpuAB on live meningococci (69).…”

mentioning

confidence: 99%

“…Therefore, we had previously developed a liquid-phase 125 I-Hb binding assay to measure the equilibrium binding kinetics of Hb to HpuAB on live meningococci (69). In those experiments, wildtype HpuAB saturably bound 125 I-Hb with a moderate affinity approximately 50-fold lower than that of the interaction of Tf with the TbpAB receptor (15,69). We did not detect significant Hb binding to mutant strains lacking either HpuA, HpuB, or both receptor components by using that assay or a solidphase dot blot analysis (69).…”

mentioning

confidence: 99%

Analysis of Haptoglobin and Hemoglobin-Haptoglobin Interactions with theNeisseria meningitidisTonB-Dependent Receptor HpuAB by Flow Cytometry

Rohde

Dyer

2004

Infect Immun

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Neisseria meningitidis expresses a two-component TonB-dependent receptor, HpuAB, which mediates hemeiron (Hm-Fe) acquisition from hemoglobin and hemoglobin-haptoglobin complexes. Due to genetic polymorphisms in the human haptoglobin gene, haptoglobin (and hemoglobin-haptoglobin) exists as three structurally distinct phenotypes. In this study, we examined the influence of the haptoglobin phenotype on the interactions of HpuAB with apo-haptoglobin and hemoglobin-haptoglobin. Growth assays confirmed that HpuAB utilizes hemoglobin-haptoglobin more efficiently than hemoglobin as an Fe source and revealed a preference for human-specific, polymeric 2-2 or 2-1 hemoglobin-haptoglobin complexes. We developed a flow cytometry-based assay to measure the binding kinetics of fluorescein-labeled ligands to HpuAB on live, intact meningococci. The binding affinity of HpuAB for hemoglobin-haptoglobin phenotypes correlated well with the ability of each ligand to support Neisseria meningitidis growth, with higher affinities exhibited for types 2-2 and 2-1 hemoglobin-haptoglobin. Saturable binding of Hb and apo-haptoglobin suggested that HpuAB-mediated utilization of hemoglobin-haptoglobin involves specific interactions with both components. In contrast to previous studies, we detected binding of HpuB expressed alone to hemoglobin, apo-haptoglobin, and hemoglobon-haptoglobin of all three phenotypes. However, in the absence of HpuA, the binding capacity and/or affinity of the receptor was reduced and the dissociation of hemoglobin was impaired. We did not detect binding of HpuA alone to hemoglobin, apo-haptoglobin, or hemoglobin-haptoglobin; however, the lipoprotein is crucial for optimal recognition and use of ligands by the receptor. Finally, this study confirmed the integral role of TonB and the proton motive force in the binding and dissociation of Hb and hemoglobin-haptoglobin from HpuAB.

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Binding and surface exposure characteristics of the gonococcal transferrin receptor are dependent on both transferrin-binding proteins

Cited by 116 publications

References 59 publications

Conservation and antigenic cross-reactivity of the transferrin-binding proteins of Haemophilus influenzae, Actinobacillus pleuropneumoniae and Neisseria meningitidis

Conservation and antigenic cross-reactivity of the transferrin-binding proteins of Haemophilus influenzae, Actinobacillus pleuropneumoniae and Neisseria meningitidis

Control of Neisseria gonorrhoeae pilin gene expression by environmental factors: involvement of the pilA/pilB regulatory genes

Analysis of Haptoglobin and Hemoglobin-Haptoglobin Interactions with theNeisseria meningitidisTonB-Dependent Receptor HpuAB by Flow Cytometry

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