Microheterogeneity of Neisseria lipooligosaccharide: analysis of a UDP-glucose 4-epimerase mutant of Neisseria meningitidis NMB

Lee, F. K. N.; Stephens, David S.; Gibson, Bradford W.; Engstrom, J J; Zhou, Daoguo; Apicella, Michael A.

doi:10.1128/iai.63.7.2508-2515.1995

Cited by 32 publications

(19 citation statements)

References 28 publications

(27 reference statements)

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“…The galE mutants used in this study exhibit a truncated LOS devoid of galactose, in which the terminal three sugar molecules of the wild-type lacto-N-neotetraose are lacking or substituted by glucose extensions (33). galE mutants of the gonococcal strain MS11 exhibit increased resistance to serum compared to that of wild-type gonococci grown in the absence of CMP-NANA and bearing unsialylated LOS (47), suggesting that there are natural antibodies in NHS which are directed against the terminal portion of the gonococcal lacto-N-neotetraose but which do not recognize the galE LOS.…”

Section: Discussionmentioning

confidence: 99%

Complement factor C3 deposition and serum resistance in isogenic capsule and lipooligosaccharide sialic acid mutants of serogroup B Neisseria meningitidis

Vogel¹,

Weinberger²,

Frank³

et al. 1997

Infect Immun

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Serogroup B meningococci express sialic acids on their surfaces as a modification of the lipooligosaccharide (LOS) and as capsular material consisting of ␣2,8-linked sialic acid homopolymers. The aim of this study was to elucidate the impact of each sialic acid component on the deposition of complement factor C3 and serum resistance. For this purpose, we used isogenic mutants deficient in capsule expression (a polysialyltransferase mutant) or sialylation of the LOS (a galE mutant) or both (a mutant with a deletion of the cps gene locus). Bactericidal assays using 40% normal human serum (NHS) demonstrated that both the capsule and LOS sialic acid are indispensable for serum resistance. By immunoblotting with monoclonal antibody MAb755 that is specific for the C3 ␣-chain, we were able to demonstrate that C3 from 40% NHS was covalently linked to the surface structures of meningococci as C3b and iC3b, irrespective of the surface sialic acid compounds. However, C3b linkage was more pronounced and occurred on a larger number of target molecules in galE mutants with nonsialylated LOS than in meningococci with wild-type LOS, irrespective of the capsule phenotype. C3b deposition was caused by both the classical pathway (CP) and the alternative pathway of complement activation. Use of 10% NHS revealed that at low serum concentrations, C3 deposition occurred via the CP and was detected primarily on nonsialylated-LOS galE mutants, irrespective of the capsular phenotype. Accordingly, immunoglobulin M (IgM) binding to meningococci from heat-inactivated NHS was demonstrated only in both encapsulated and unencapsulated galE mutants. In contrast, inhibition of IgA binding required both encapsulation and LOS sialylation. We conclude that serum resistance in wild-type serogroup B meningococci can only be partly explained by an alteration of the C3b linkage pattern, which seems to depend primarily on the presence of wild-type LOS, since a serum-resistant phenotype also requires capsule expression.

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Section: Discussionmentioning

confidence: 99%

Complement factor C3 deposition and serum resistance in isogenic capsule and lipooligosaccharide sialic acid mutants of serogroup B Neisseria meningitidis

Vogel¹,

Weinberger²,

Frank³

et al. 1997

Infect Immun

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“…These mutants were defective in capsule formation, LOS sialylation, or altered in LOS structure or had a combination of these phenotypes. The characteristics of strain NMB are summarized in Table 1, and the creation and selection of the mutants have been described previously (29,30,32,56,57,60,69) or are described below. The serum-resistant gonococcal strain FA19 was also used (55).…”

Section: Methodsmentioning

confidence: 99%

“…LOS immu- notyping was performed as previously described (44). Structural analysis of LOS expressed by strain NMB and the mutants was performed by Tricine SDS-PAGE, compositional studies, nuclear magnetic resonance (NMR), and mass spectrometry (29,30,32,42). Immunoblots and whole-cell enzyme-linked immunosorbent assays (57,59,60) were used to quantitate amounts of (␣238)-linked polysialic acid capsule.…”

Section: Methodsmentioning

confidence: 99%

“…We next asked whether LOS structure influenced serum bactericidal activity in an encapsulated meningococcal background. A mutation in the ␣2,3 sialyltransferase gene, lst, was (32). (D) The LOS from HepI␤1-4 glucosyl transferase mutant NMBlgtF::aphA-3 (nonpolar lgtF mutant) had a GlcNAc/Hep ratio of 1:2.125 with no other hexoses detected, indicating that the predominant structure was Hep 2 (GlcNAc)KDO 2 3lipid A (29).…”

Section: Lst Mutation [Encapsulated; Gal␤134glcnac␤133gal␤13 4glc␤134mentioning

confidence: 99%

“…2A). The mutation was due to a Tn916 insertion in the amino terminus of the functional copy of the UDP-Glc4-epimerase, galE (32). UDP-Glc 4-epimerase activity was present in N. meningitidis NMB but not in SS3, indicating that the Tn916 insertion had abolished this activity.…”

Section: Gale Mutation [Encapsulated; Glc N -Hep 2 (Glcnacglc)pea3 Kmentioning

confidence: 99%

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The (α2→8)-Linked Polysialic Acid Capsule and Lipooligosaccharide Structure Both Contribute to the Ability of Serogroup BNeisseria meningitidisTo Resist the Bactericidal Activity of Normal Human Serum

Kahler

Martin²,

Shih³

et al. 1998

Infect Immun

143

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The molecular basis for the resistance of serogroup BNeisseria meningitidis to the bactericidal activity of normal human sera (NHS) was examined with a NHS-resistant, invasive serogroup B meningococcal isolate and genetically and structurally defined capsule-, lipooligosaccharide (LOS)-, and sialylation-altered mutants of the wild-type strain. Expression of the (α2→8)-linked polysialic acid serogroup B capsule was essential for meningococcal resistance to NHS. The very NHS-sensitive phenotype of acapsular mutants (99.9 to 100% killed in 10, 25, and 50% NHS) was not rescued by complete LOS sialylation or changes in LOS structure. However, expression of the capsule was necessary but not sufficient for a fully NHS-resistant phenotype. In an encapsulated background, loss of LOS sialylation by interrupting the α2,3 sialyltransferase gene,lst, increased sensitivity to 50% NHS. In contrast, replacement of the lacto-N-neotetraose α-chain (Galβ1-4GlcNAcβ1-3Galβ1-4Glc) with glucose extensions (GlcN) in a galE mutant resulted in a strain resistant to killing by 50% NHS at all time points. Encapsulated meningococci expressing a Hep2(GlcNAc)→KDO2→lipid A LOS without an α-chain demonstrated enhanced sensitivity to 50% NHS (98% killed at 30 min) mediated through the antibody-dependent classical complement pathway. Encapsulated LOS mutants expressing truncated Hep2→KDO2→lipid A and KDO2→lipid A structures were also sensitive to 50% NHS (98 to 100% killed at 30 min) but, unlike the wild-type strain and mutants with larger oligosaccharide structures, they were killed by hypogammaglobulinemic sera. These data indicate that encapsulation is essential but that the LOS structure contributes to the ability of serogroup B N. meningitidis to resist the bactericidal activity of NHS.

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The Effect of galE Gene Inactivation on Lipopolysaccharide Profile of Helicobacter pylori

Kwon

Woo

Perng

et al. 1998

Current Microbiology

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The galE gene product, UDP-galactose 4-epimerase, mediates the incorporation of galactose in extracellular polysaccharide materials such as the O-side chain of lipopolysaccharide (LPS). The O-side chain in H. pylori LPS has been shown to cross-react with Lewis x and/or y blood group antigens, suggesting its potential involvement in H. pylori-linked autoimmune disease. To study its role in H. pylori LPS biosynthesis, the galE gene was cloned, sequenced, and a galE-knockout H. pylori strain was constructed. The H. pylori galE gene encoded a protein of 344 amino acids with a molecular weight of 39K. The LPS profile from the galE-knockout H. pylori strain showed a lower molecular weight than that of the parental strain, indicating the involvement of the galE gene in LPS biosynthesis of H. pylori.

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Microheterogeneity of Neisseria lipooligosaccharide: analysis of a UDP-glucose 4-epimerase mutant of Neisseria meningitidis NMB

Cited by 32 publications

References 28 publications

Complement factor C3 deposition and serum resistance in isogenic capsule and lipooligosaccharide sialic acid mutants of serogroup B Neisseria meningitidis

Complement factor C3 deposition and serum resistance in isogenic capsule and lipooligosaccharide sialic acid mutants of serogroup B Neisseria meningitidis

The (α2→8)-Linked Polysialic Acid Capsule and Lipooligosaccharide Structure Both Contribute to the Ability of Serogroup BNeisseria meningitidisTo Resist the Bactericidal Activity of Normal Human Serum

The Effect of galE Gene Inactivation on Lipopolysaccharide Profile of Helicobacter pylori

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