Analysis of the expression of outer-membrane proteins in Neisseria meningitidis in iron-replete and iron-deficient media

FerreirÃ3s, C.M.; Criado, M.T.; Rao, Mrinalini C.; Pintor, M.

doi:10.1111/j.1574-6968.1990.tb03797.x

Cited by 8 publications

(9 citation statements)

References 25 publications

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“…The cells grown under iron-restricted conditions (of all serogroups and serotypes examined) bind 2-to 35-fold more gold-labelled HTF than do cells grown under iron-sufficient conditions, indicating the increased expression of HTF receptor activity under such stress. The findings of increased expression of the HTF receptor under iron limitation are in general agreement with results obtained from studies on whole cells and from Western blot analysis of OMPs of N. meningitidis grown under different conditions (1,8,9,13,17). In contrast, these findings do not agree with those reported by Simonson et al (14), who concluded that iron-replete and iron-restricted cells bind approximately the same number of HTF molecules.…”

Section: Discussionsupporting

confidence: 81%

Localization of the meningococcal receptors for human transferrin

et al. 1993

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The interaction between gold-labelled human transferrin (Au-HTF) with live meningococci after growth in vivo or in different in vitro conditions was examined by electron microscopy to localize and quantify the numbers of HTF-binding sites on the cell surface. It was clearly demonstrated that HTF binds to the surface of live meningococci (of different serogroups and serotypes) after growth in either iron-sufficient or iron-restricted cultures, although the degree of labelling was always higher (2-to 35-fold) in the latter case. The commensal Neisseria polysaccharea behaved similarly. Ultrathin sections showed that Au-HTF was localized predominantly on the outer membrane of the cells and vesicles, with hardly any internalization. Au-HTF labelling on meningococci was significantly reduced after incubation with unlabelled HTF or with rabbit antiserum containing antibodies against transferrin-binding proteins (TBPs), demonstrating the specificity of

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Section: Discussionsupporting

confidence: 81%

Localization of the meningococcal receptors for human transferrin

et al. 1993

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“…Excreted blebs and bacterial outer membranes were obtained as previously described [19] from cultures grown in MH or MH-EDDA for SDS-PAGE analysis, and only from those grown in MH-EDDA for TBP2 isolation. The cultures were centrifuged at 48 000 x g, the pellets being resuspended in 0.1 M acetate buffer-0.2 M lithium chloride (pH 5.8), with two 10-s ultrasonic pulses, incubated for 2 h at 45°C in a shaking water bath and passed through a 21-gauge needle.…”

Section: Extraction Of Ompsmentioning

confidence: 99%

Purification of the Neisseria meningitidis transferrin binding protein-2 (TBP2) to homogeneity using column chromatography

Ferrón¹

1993

FEMS Microbiology Letters

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A method for purifying TBP2 from N. meningitidis has been developed using affinity chromatography on Tf-agarose followed by ion exchange chromatography; the Tf-binding activity of fractions was evaluated by a dot-blot technique. This method allowed the purification of the TBP2 in milder conditions than those used previously and to a high degree of homogeneity as was demonstrated by Coomassie brilliant blue or Silver staining after SDS-PAGE electrophoresis. The SDS-PAGE profile of the material obtained in the Tf-agarose affinity chromatography step shows only two detectable proteins, identified as the TBP1 and the TBP2, with a small amount of contamination. Passage through a MonoQ HR anion exchange column, allowed the isolation of TBP2 in the absence of TBP1. Our results demonstrate the conservation of the antigenic reactivity of this protein, which produces monospecific serum with the antibodies elicited reacting exclusively with the TBP2 in whole outer membrane vesicles.

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“…The outer membrane composition of bacteria grown in normal culture media, in which iron is freely available, can be significantly different from that of invasive bacteria recovered directly from hosts, especially in the case of N. meningitidis. In particular, iron-regulated OMPs (IROMPs), some of which are involved in iron uptake mechanisms (26,27), are synthesized only under iron restriction (11,19) and later the antigenicity of the outer membrane of N. meningitidis (2-4, 15, 17).…”

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confidence: 99%

Immunogenicity and antigenic heterogeneity of a human transferrin-binding protein in Neisseria meningitidis

et al. 1992

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Growing Neisseria meningitidis on an iron restriction medium induces the synthesis of new outer membrane proteins, some of them true iron-regulated outer membrane proteins (IROMPs) and others synthesized because of the stress produced by the iron restriction. Some of these proteins are antigenic and can be considered for the development of vaccines; this is especially desirable in the case of N. meningitidis serogroup B, for which polysaccharide vaccines are not efficient. The antigenicity of N. meningitidis 37- and 70-kDa IROMPs has been studied previously; in this work, we studied the immunogenicity and antigenic heterogeneity of another IROMP, the human transferrin-binding protein 2 (TBP2), which seems to be indispensable for meningococcal growth inside the host. Mice were inoculated with purified outer membrane vesicles (blebs) from 5 selected N. meningitidis strains, and the five serum samples obtained were analyzed for anti-TBP2 antibodies by using the homologous strain and for cross-reactivity with the TBP2 of the 4 other selected strains and another 35 heterologous N. meningitidis strains. The TBP2s of the 5 strains tested were all immunogenic in mice to various degrees depending on the strain, and all five TBP2s shared one or more epitopes with heterologous strains (as shown by the cross-reactivities of the five serum samples), although the number of cross-reacting strains was very variable, ranging from 2 for strain V002 to 35 for strain P391. This suggests that the TBP2 epitopes of different strains differ in nature or in their accessibility to the immune system. Under the iron restriction conditions used, all strains synthesized a non-TBP2 antigenic 56-kDa protein thought to be a stress protein.

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Analysis of the expression of outer-membrane proteins in Neisseria meningitidis in iron-replete and iron-deficient media

Cited by 8 publications

References 25 publications

Localization of the meningococcal receptors for human transferrin

Localization of the meningococcal receptors for human transferrin

Purification of the Neisseria meningitidis transferrin binding protein-2 (TBP2) to homogeneity using column chromatography

Immunogenicity and antigenic heterogeneity of a human transferrin-binding protein in Neisseria meningitidis

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