1
|
Cheng H, Yang Z, Estabrook MM, John CM, Jarvis GA, McLaughlin S, Griffiss JM. Human lipooligosaccharide IGG that prevents endemic meningococcal disease recognizes an internal lacto-N-neotetraose structure. J Biol Chem 2011; 286:43622-43633. [PMID: 22027827 DOI: 10.1074/jbc.m111.291583] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Antibodies that initiate complement-mediated killing of Neisseria meningitidis as they enter the bloodstream from the oropharynx protect against disseminated disease. Human IgGs that bind the neisserial L7 lipooligosaccharide (LOS) are bactericidal for L3,7 and L2,4 meningococci in the presence of human complement. These strains share a lacto-N-neotetraose (nLc4) LOS α chain. We used a set of mutants that have successive saccharide deletions from the nLc4 α chain to characterize further the binding and bactericidal activity of nLc4 LOS IgG. We found that the nLc4 α chain conforms at least four different antigens. We separately purified IgG that required the nLc4 (non-reducing) terminal galactose (Gal) for binding and IgG that bound the truncated nLc3 α chain that lacks this Gal residue. IgG that bound the internal nLc3 α chain killed both L3,7 and L2,4 strains, whereas IgG that required the nLc4 terminal Gal residue for binding killed L2,4 stains but not L3,7 strains. These results show that the diversity of LOS antibodies in human serum is as much a function of the conformation of multiple antigens by a single glycoform as of the production of multiple glycoforms. Differences in sensitivity to killing by human nLc4 LOS IgG may account for the fact that fully two-thirds of endemic group B meningococcal disease in infants and children is caused by L3,7 strains, but only 20% is caused by L2,4 stains.
Collapse
Affiliation(s)
- Hui Cheng
- Department of Veterans Affairs Medical Center, San Francisco, California 94121
| | - Zhijie Yang
- Department of Veterans Affairs Medical Center, San Francisco, California 94121
| | - Michele M Estabrook
- Department of Veterans Affairs Medical Center, San Francisco, California 94121; Department of Pediatrics, University of California, San Francisco, California 94121
| | - Constance M John
- Department of Veterans Affairs Medical Center, San Francisco, California 94121
| | - Gary A Jarvis
- Department of Veterans Affairs Medical Center, San Francisco, California 94121; Department of Laboratory Medicine, University of California, San Francisco, California 94121
| | | | - J McLeod Griffiss
- Department of Veterans Affairs Medical Center, San Francisco, California 94121; Department of Laboratory Medicine, University of California, San Francisco, California 94121.
| |
Collapse
|
2
|
Stein DC, Miller CJ, Bhoopalan SV, Sommer DD. Sequence-based predictions of lipooligosaccharide diversity in the Neisseriaceae and their implication in pathogenicity. PLoS One 2011; 6:e18923. [PMID: 21533118 PMCID: PMC3078933 DOI: 10.1371/journal.pone.0018923] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 03/11/2011] [Indexed: 12/31/2022] Open
Abstract
Endotoxin [Lipopolysaccharide (LPS)/Lipooligosaccharide (LOS)] is an important virulence determinant in gram negative bacteria. While the genetic basis of endotoxin production and its role in disease in the pathogenic Neisseria has been extensively studied, little research has focused on the genetic basis of LOS biosynthesis in commensal Neisseria. We determined the genomic sequences of a variety of commensal Neisseria strains, and compared these sequences, along with other genomic sequences available from various sequencing centers from commensal and pathogenic strains, to identify genes involved in LOS biosynthesis. This allowed us to make structural predictions as to differences in LOS seen between commensal and pathogenic strains. We determined that all neisserial strains possess a conserved set of genes needed to make a common 3-Deoxy-D-manno-octulosonic acid -heptose core structure. However, significant genomic differences in glycosyl transferase genes support the published literature indicating compositional differences in the terminal oligosaccharides. This was most pronounced in commensal strains that were distally related to the gonococcus and meningococcus. These strains possessed a homolog of heptosyltransferase III, suggesting that they differ from the pathogenic strains by the presence a third heptose. Furthermore, most commensal strains possess homologs of genes needed to synthesize lipopolysaccharide (LPS). N. cinerea, a commensal species that is highly related to the gonococcus has lost the ability to make sialyltransferase. Overall genomic comparisons of various neisserial strains indicate that significant recombination/genetic acquisition/loss has occurred within the genus, and this muddles proper speciation.
Collapse
Affiliation(s)
- Daniel C Stein
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America.
| | | | | | | |
Collapse
|
3
|
Retargeting R-type pyocins to generate novel bactericidal protein complexes. Appl Environ Microbiol 2008; 74:3868-76. [PMID: 18441117 DOI: 10.1128/aem.00141-08] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
R-type pyocins are high-molecular-weight bacteriocins that resemble bacteriophage tail structures and are produced by some Pseudomonas aeruginosa strains. R-type pyocins kill by dissipating the bacterial membrane potential after binding. The high-potency, single-hit bactericidal kinetics of R-type pyocins suggest that they could be effective antimicrobials. However, the limited antibacterial spectra of natural R-type pyocins would ultimately compromise their clinical utility. The spectra of these protein complexes are determined in large part by their tail fibers. By replacing the pyocin tail fibers with tail fibers of Pseudomonas phage PS17, we changed the bactericidal specificity of R2 pyocin particles to a different subset of P. aeruginosa strains, including some resistant to PS17 phage. We further extended this idea by fusing parts of R2 tail fibers with parts of tail fibers from phages that infect other bacteria, including Escherichia coli and Yersinia pestis, changing the killing spectrum of pyocins from P. aeruginosa to the bacterial genus, species, or strain that serves as a host for the donor phage. The assembly of active R-type pyocins requires chaperones specific for the C-terminal portion of the tail fiber. Natural and retargeted R-type pyocins exhibit narrow bactericidal spectra and thus can be expected to cause little collateral damage to the healthy microbiotae and not to promote the horizontal spread of multidrug resistance among bacteria. Engineered R-type pyocins may offer a novel alternative to traditional antibiotics in some infections.
Collapse
|
4
|
O'Connor ET, Swanson KV, Cheng H, Fluss K, Griffiss JM, Stein DC. Structural Requirements for Monoclonal Antibody 2-1-L8 Recognition of Neisserial Lipooligosaccharides. Hybridoma (Larchmt) 2008; 27:71-9. [DOI: 10.1089/hyb.2007.0552] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Ellen T. O'Connor
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland
| | - Karen V. Swanson
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland
- Department of Laboratory Medicine and Veterans Affairs, VA Medical Center, University of California, San Francisco, California
| | - Hui Cheng
- Department of Laboratory Medicine and Veterans Affairs, VA Medical Center, University of California, San Francisco, California
| | - Kathryn Fluss
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland
| | - J. McLeod Griffiss
- Department of Laboratory Medicine and Veterans Affairs, VA Medical Center, University of California, San Francisco, California
| | - Daniel C. Stein
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland
| |
Collapse
|
5
|
O'Connor ET, Piekarowicz A, Swanson KV, Griffiss JM, Stein DC. Biochemical analysis of Lpt3, a protein responsible for phosphoethanolamine addition to lipooligosaccharide of pathogenic Neisseria. J Bacteriol 2006; 188:1039-48. [PMID: 16428408 PMCID: PMC1347319 DOI: 10.1128/jb.188.3.1039-1048.2006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The inner core of neisserial lipooligosaccharide (LOS) contains heptose residues that can be decorated by phosphoethanolamine (PEA). PEA modification of heptose II (HepII) can occur at the 3, 6, or 7 position(s). We used a genomic DNA sequence of lpt3, derived from Neisseria meningitidis MC58, to search the genomic sequence of N. gonorrhoeae FA1090 and identified a homolog of lpt3 in N. gonorrhoeae. A PCR amplicon containing lpt3 was amplified from F62DeltaLgtA, cloned, mutagenized, and inserted into the chromosome of N. gonorrhoeae strain F62DeltaLgtA, producing strain F62DeltaLgtAlpt3::Tn5. LOS isolated from this strain lost the ability to bind monoclonal antibody (MAb) 2-1-L8. Complementation of this mutation by genetic removal of the transposon insertion restored MAb 2-1-L8 binding. Mass spectrometry analysis of LOS isolated from the F62DeltaLgtA indicated that this strain contained two PEA modifications on its LOS. F62DeltaLgtAlpt3::Tn5 lacked a PEA modification on its LOS, a finding consistent with the hypothesis that lpt3 encodes a protein mediating PEA addition onto gonococcal LOS. The DNA encoding lpt3 was cloned into an expression vector and Lpt3 was purified. Purified Lpt3 was able to mediate the addition of PEA to LOS isolated from F62DeltaLgtAlpt3::Tn5.
Collapse
Affiliation(s)
- Ellen T O'Connor
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | | | | | | | | |
Collapse
|
6
|
Filiatrault MJ, Munson RS, Campagnari AA. Genetic analysis of a pyocin-resistant lipooligosaccharide (LOS) mutant of Haemophilus ducreyi: restoration of full-length LOS restores pyocin sensitivity. J Bacteriol 2001; 183:5756-61. [PMID: 11544241 PMCID: PMC95470 DOI: 10.1128/jb.183.19.5756-5761.2001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
DNA sequence and Southern blot analyses were used to determine the genetic defect of a Haemophilus ducreyi pyocin-resistant lipooligosaccharide (LOS) mutant, HD35000R. The region of the HD35000R chromosome containing the suspected mutation was amplified, and sequence analysis detected a 3,189-bp deletion. This deletion resulted in the loss of the entire waaQ gene, another open reading frame that encodes a putative homolog to a hypothetical protein (HI0461) of H. influenzae, the gene encoding an argininosuccinate synthase homolog, and a change in the 3' sequence of the lgtF gene. Southern blot analysis confirmed that no genomic rearrangements had occurred. Isogenic LOS mutants and the respective complemented mutants were evaluated for susceptibility to pyocin C. The mutants expressing truncated LOS were resistant to lysis by pyocin C, and complementation restored sensitivity to the pyocin. We conclude that HD35000R is defective in both glycosyltransferase genes and that pyocin resistance is due to truncation of the full-length LOS molecule.
Collapse
Affiliation(s)
- M J Filiatrault
- Department of Microbiology, State University of New York at Buffalo, Buffalo, New York 14214, USA
| | | | | |
Collapse
|
7
|
Abstract
Neisserial lipooligosaccharide (LOS) contains three oligosaccharide chains, termed the alpha, beta, and gamma chains. We used Southern hybridization experiments on DNA isolated from various Neisseria spp. to determine if strains considered to be nonpathogenic possessed DNA sequences homologous with genes involved in the biosynthesis of these oligosaccharide chains. The presence or absence of specific genes was compared to the LOS profiles expressed by each strain, as characterized by their mobilities on sodium dodecyl sulfate-polyacrylamide gel electrophoresis gel and their reactivities with various LOS-specific monoclonal antibodies. A great deal of heterogeneity was seen with respect to the presence of genes encoding glycosyltransferases in Neisseria. All pathogenic species were found to possess DNA sequences homologous with the lgt gene cluster, a group of genes needed for the synthesis of the alpha chain. Some of these genes were also found to be present in strains considered to be nonpathogenic, such as Neisseria lactamica, N. subflava, and N. sicca. Some nonpathogenic Neisseria spp. were able to express high-molecular-mass LOS structures, even though they lacked the DNA sequences homologous with rfaF, a gene whose product must act before gonococcal and meningococcal LOS can be elongated. Using a PCR amplification strategy, in combination with DNA sequencing, we demonstrated that N. subflava 44 possessed lgtA, lgtB, and lgtE genes. The predicted amino acid sequence encoded by each of these genes suggested that they encoded functional proteins; however, structural analysis of LOS isolated from this strain indicated that the bulk of its LOS was not modified by these gene products. This suggests the existence of an additional regulatory mechanism that is responsible for the limited expression of these genes in this strain.
Collapse
Affiliation(s)
- D Arking
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742, USA
| | | | | |
Collapse
|
8
|
Tong Y, Reinhold V, Reinhold B, Brandt B, Stein DC. Structural and immunochemical characterization of the lipooligosaccharides expressed by Neisseria subflava 44. J Bacteriol 2001; 183:942-50. [PMID: 11208793 PMCID: PMC94962 DOI: 10.1128/jb.183.3.942-950.2001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neisserial lipooligosaccharides (LOSs) are a family of complex cell surface glycolipids. We used mass spectrometry techniques (electrospray ionization, collision-induced dissociation, and multiple step), combined with fluorophore-assisted carbohydrate electrophoresis monosaccharide composition analysis, to determine the structure of the two low-molecular-mass LOS molecules (LOSI and LOSII) expressed by Neisseria subflava 44. We determined that LOSI contains one glucose on both the alpha and beta chains. LOSII is structurally related to LOSI and differs from it by the addition of a hexose (either glucose or galactose) on the alpha chain. LOSI and LOSII were able to bind monoclonal antibody (MAb) 25-1-LC1 when analyzed by Western blotting experiments. We used a set of genetically defined Neisseria gonorrhoeae mutants that expressed single defined LOS epitopes and a group of Neisseria meningitidis strains that expresses chemically defined LOS components to determine the structures recognized by MAb 25-1-LC1. We found that extensions onto the beta-chain glucose of LOSI block the recognition by this MAb, as does further elongation from the LOSII alpha chain. The LOSI structure was determined to be the minimum structure that is recognized by MAb 25-1-LC1.
Collapse
Affiliation(s)
- Y Tong
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742, USA
| | | | | | | | | |
Collapse
|
9
|
Steeghs L, Kuipers B, Hamstra HJ, Kersten G, van Alphen L, van der Ley P. Immunogenicity of outer membrane proteins in a lipopolysaccharide-deficient mutant of Neisseria meningitidis: influence of adjuvants on the immune response. Infect Immun 1999; 67:4988-93. [PMID: 10496868 PMCID: PMC96843 DOI: 10.1128/iai.67.10.4988-4993.1999] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/1999] [Accepted: 07/06/1999] [Indexed: 11/20/2022] Open
Abstract
The immunogenicity of outer membrane complexes (OMCs) or heat-inactivated bacteria of a lipopolysaccharide (LPS)-deficient mutant derived from meningococcal strain H44/76 was studied. The immune response in BALB/c mice to the major outer membrane proteins was poor compared to the immune response elicited by wild-type immunogens. However, addition of external H44/76 LPS to mutant OMCs entirely restored the immune response. By using an LPS-deficient mutant, it may be possible to substitute a less toxic compound as adjuvant in meningococcal outer membrane vaccines. Therefore, a broad panel of adjuvants were tested for their potential to enhance the immunogenicity of LPS-deficient OMCs. AlPO(4), Rhodobacter sphaeroides LPS, monophosphoryl lipid A and alkali-hydrolyzed meningococcal LPS showed significantly lower adjuvant activity than did H44/76 LPS. Adjuvant activity similar to H44/76 LPS was found for Escherichia coli LPS, meningococcal icsB and rfaC LPS, QuilA, subfractions of QuilA, and MF59. Good adjuvant activity was also found with meningococcal htrB1 LPS, containing penta-acylated lipid A. Antisera elicited with the less active adjuvants showed relatively high immunoglobulin G1 (IgG1) titers, whereas strong adjuvants also induced high IgG2a and IgG2b responses in addition to IgG1. Antisera with the IgG2a and IgG2b isotypes showed high bactericidal activity, indicating that adjuvants promoting the IgG2a and IgG2b response contribute most to the protective mechanism. Thus, this study demonstrates that the immunogenicity of meningococcal LPS-deficient OMCs can be restored by using less toxic adjuvants, which opens up new avenues for development of vaccines against meningococcal disease.
Collapse
Affiliation(s)
- L Steeghs
- Laboratory of Vaccine Research, National Institute of Public Health and the Environment, 3720 BA Bilthoven, The Netherlands.
| | | | | | | | | | | |
Collapse
|
10
|
Kahler CM, Stephens DS. Genetic basis for biosynthesis, structure, and function of meningococcal lipooligosaccharide (endotoxin). Crit Rev Microbiol 1999; 24:281-334. [PMID: 9887366 DOI: 10.1080/10408419891294216] [Citation(s) in RCA: 123] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The exclusive human pathogen Neisseria meningitidis expresses lipooligosaccharide (LOS), an endotoxin that is structurally distinct from the lipopolysaccharides (LPS) of enteric Gram-negative bacilli. Differences that appear to be biologically important occur in the composition and attachment of acyl chains to lipid A, phosphorylation patterns of lipid A, and the incorporation and phosphorylation of sugar residues in the LOS inner core. Further, unlike most enteric LPS, only two to five sugar residues are attached to the meningococcal LOS inner core, and there are no multiple repeating units of O-antigens. In contrast to Escherichia coli, where the LPS biosynthesis genes are organized as large operons, the meningococcal LOS biosynthesis genes are organized into small operons or are located individually in the chromosome. Some of these genetic loci in meningococci and gonococci display polymorphisms caused by localized chromosomal rearrangements. One mechanism of antigenic variation of meningococci LOS is the regulation of glycosyltransferase activity by slipped strand mispairing of homopolymeric tracts within the 5' end of the genes encoding these enzymes, resulting in the addition of different sugar residues to the LOS molecule. Meningococcal LOS is a critical virulence factor in N. meningitidis infections and is involved in many aspects of pathogenesis, including the colonization of the human nasopharynx, survival after bloodstream invasion, and the inflammation associated with the morbidity and mortality of meningococcemia and meningitis. Meningococcal LOS, which is a component of serogroup B meningococcal vaccines currently in clinical trials, has been proposed as a candidate for a new generation of meningococcal vaccines. The rapidly expanding knowledge of the genetic basis for biosynthesis, structure, and regulation of meningococcal LOS provides insights into unique endotoxin structures and the precise role of LOS in the pathogenesis of meningococcal disease.
Collapse
Affiliation(s)
- C M Kahler
- Department of Medicine, Emory University School of Medicine, Atlanta, Georgia 30303, USA
| | | |
Collapse
|
11
|
Banerjee A, Wang R, Uljon SN, Rice PA, Gotschlich EC, Stein DC. Identification of the gene (lgtG) encoding the lipooligosaccharide beta chain synthesizing glucosyl transferase from Neisseria gonorrhoeae. Proc Natl Acad Sci U S A 1998; 95:10872-7. [PMID: 9724797 PMCID: PMC27988 DOI: 10.1073/pnas.95.18.10872] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/08/1998] [Indexed: 11/18/2022] Open
Abstract
The lipooligosaccharide from Neisseria gonorrhoeae (GC), consists of lipid A, an oligosaccharide core and three branches, alpha, beta, and gamma. We report the cloning of the gene (lgtG, lipooligosaccharide glycosyl transferase G) encoding the glucosyl transferase of GC that initiates the beta chain which consists of a lactosyl moiety. This gene contains a homopolymeric tract of cytidine [poly(C)] and we demonstrate that changes in the number of Cs in poly(C) account for the variation of beta chain expression in different GC strains. Biochemical analyses and mass spectrometry clearly attribute the reactivity of mAb 2C7 to the presence of the lactosyl beta chain. In addition, we demonstrate that in the absence of the lactosyl group, a phosphoethanolamine is added to generate a new antigenic epitope as evidenced by the gain of reactivity to mAb 2-L1-8. These results show that, like the alpha chain, the beta chain of lipooligosaccharide is subject to antigenic variation.
Collapse
Affiliation(s)
- A Banerjee
- Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, New York, NY 10021, USA
| | | | | | | | | | | |
Collapse
|
12
|
Levin JC, Stein DC. Cloning, complementation, and characterization of an rfaE homolog from Neisseria gonorrhoeae. J Bacteriol 1996; 178:4571-5. [PMID: 8755886 PMCID: PMC178225 DOI: 10.1128/jb.178.15.4571-4575.1996] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Neisseria gonorrhoeae WS1 is a spontaneous pyocin (a bacteriocin produced by Pseudomonas aeruginosa)-resistant mutant of N. gonorrhoeae FA19 that produces a truncated lipooligosaccharide (LOS) and is non-transformable. The LOS-specific mutation in WS1 was moved into a transformable background by transforming FA19 with chromosomal DNA from WS1 (generating strain JWS-1). A clone (pJCL2) capable of restoring JWS-1 to wild-type LOS expression, as detected by its acquisition of reactivity with monoclonal antibodies and by its complemented sodium dodecyl sulfate-polyacrylamide gel electrophoresis profile, was isolated. Sequential unidirectional deletion and DNA sequence analysis of pJCL2 identified an open reading frame, designated lsi-7, that could complement the defect in JWS-1. Homology searches against various databases indicated that lsi-7 bad homology with several Escherichia coli genes involved in the phosphorylation of sugars. lsi-7 is adjacent to the lsi-6 gene, another gene involved in LOS biosynthesis. Complementation studies using Salmonella typhimurium lipopolysaccharide mutants showed lsi-6 and lsi-7 to be gonococcal homologs of S. typhimurium rfaD and rfaE, respectively. Reverse transcriptase PCR analysis demonstrated that lsi-6 and lsi-7 are part of the same transcriptional unit.
Collapse
Affiliation(s)
- J C Levin
- Department of Microbiology, University of Maryland, College Park, Maryland 20742, USA
| | | |
Collapse
|
13
|
Kahler CM, Carlson RW, Rahman MM, Martin LE, Stephens DS. Inner core biosynthesis of lipooligosaccharide (LOS) in Neisseria meningitidis serogroup B: identification and role in LOS assembly of the alpha1,2 N-acetylglucosamine transferase (RfaK). J Bacteriol 1996; 178:1265-73. [PMID: 8631701 PMCID: PMC177798 DOI: 10.1128/jb.178.5.1265-1273.1996] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
A lipooligosaccharide (LOS) mutant of Neisseria meningitidis serogroup B strain NMB (immunotype L3,7,9) was identified in a Tn916 (tetM) mutant bank by loss of reactivity with monoclonal antibody 3F11, which recognizes the terminal Galbeta1-->4GlcNAc epitope in the lacto-N-neotetraose moiety of the wild-type LOS structure. The mutant, designated 559, was found to express a truncated LOS of 3.0 kDa. Southern and PCR analyses demonstrated that there was a single intact Tn916 insertion (class I) in the mutant 559 chromosome. Linkage of the LOS phenotype and the Tn916 insertion was confirmed by transformation of the wild-type parent. Nucleotide sequence analysis of the region surrounding the transposition site revealed a 1,065-bp open reading frame (ORF). A homology search of the GenBank/EMBL database revealed that the amino acid sequence of this ORF had 46.8% similarity and 21.2% identity with the alpha1,2 N-acetylglucosamine transferase (RfaK) from Salmonella typhimurium. Glycosyl composition and linkage analysis of the LOS produced by mutant 559 revealed that the lacto-N-neotetraose group which is attached to heptose I (HepI) and the N-acetylglucosamine and glucose residues that are attached to HepII in the inner core of the parental LOS were absent. These analyses also showed that the HepII residue in both the parent and the mutant LOS molecules was phosphorylated, presumably by a phosphoethanolamine substituent. The insertion of nonpolar and polar antibiotic resistance cartridges into the parental rfaK gene resulted in the expression of LOS with the same mobility as that produced by mutant 559. This result indicated that the inability to add the lacto-N-neotetraose group to the 559 LOS is not due to a polar effect on a gene(s) downstream of rfaK. Our data indicate that we have identified the meningococcal alpha1,2 N-acetylglucosamine transferase responsible for the addition of N-acetylglucosamine to HepII. We propose that the lack of alpha-chain extension from HepI in the LOS of mutant 559 may be due to structural constraints imposed by the incomplete biosynthesis of the LOS inner core.
Collapse
Affiliation(s)
- C M Kahler
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | | | | | | | | |
Collapse
|
14
|
Danaher RJ, Levin JC, Arking D, Burch CL, Sandlin R, Stein DC. Genetic basis of Neisseria gonorrhoeae lipooligosaccharide antigenic variation. J Bacteriol 1995; 177:7275-9. [PMID: 8522539 PMCID: PMC177611 DOI: 10.1128/jb.177.24.7275-7279.1995] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Neisseria gonorrhoeae lipooligosaccharide (LOS) undergoes antigenic variation at a high rate, and this variation can be monitored by changes in a strain's ability to bind LOS-specific monoclonal antibodies. We report here the cloning and identification of a gene, lsi-2, that can mediate this variation. The DNA sequence of lsi-2 has been determined for N. gonorrhoeae 1291, a strain that expresses a high-molecular-mass LOS, and a derivative of this strain, RS132L, that produces a truncated LOS. In the parental strain, lsi-2 contains a string of 12 guanines in the middle of its coding sequence. In cells that had antigenically varied to produce a truncated LOS, the number of guanines in lsi-2 was altered. Site-specific deletions were constructed to verify that expression of a 3.6-kDa LOS is due to alterations in lsi-2.
Collapse
Affiliation(s)
- R J Danaher
- Department of Microbiology, University of Maryland, College Park 20742, USA
| | | | | | | | | | | |
Collapse
|
15
|
van Putten JP, Robertson BD. Molecular mechanisms and implications for infection of lipopolysaccharide variation in Neisseria. Mol Microbiol 1995; 16:847-53. [PMID: 7476183 DOI: 10.1111/j.1365-2958.1995.tb02312.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The lipopolysaccharides of the pathogenic Neisseria species are subject to structural variation owing to a combination of intrinsic changes in lipopolysaccharide (LPS) biosynthesis and external modification of the LPS molecule with sialic acid. This variation appears to control bacterial behaviour by altering their ability to interact with human cells and to evade host immune defences. This interconversion of LPS phenotypes, which is also observed during the natural infection, is probably due to environmental regulation of LPS biosynthesis superimposed on spontaneous changes in the DNA of distinct LPS loci. LPS variation may be a common strategy of mucosal pathogens to colonize and persist within the human host.
Collapse
Affiliation(s)
- J P van Putten
- Max-Planck-Institut fuer Biologie, Infektionsbiologie, Tuebingen, Germany
| | | |
Collapse
|
16
|
Lucas CE, Hagman KE, Levin JC, Stein DC, Shafer WM. Importance of lipooligosaccharide structure in determining gonococcal resistance to hydrophobic antimicrobial agents resulting from the mtr efflux system. Mol Microbiol 1995; 16:1001-9. [PMID: 7476176 DOI: 10.1111/j.1365-2958.1995.tb02325.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Levels of gonococcal resistance to antimicrobial hydrophobic agents (HAs) are controlled by the mtr (multiple transferrable resistance) system, composed of the mtrRCDE genes. The mtrR gene encodes a transcriptional repressor that appears to regulate expression of the upstream and divergent mtrCDE operon. The mtrCDE genes encode membrane proteins analogous to the MexABOprK proteins of Pseudomonas aeruginosa that mediate export of structurally diverse antimicrobial agents. In this study we found that a single base pair deletion in a 13 bp inverted repeat sequence within the mtrR promoter resulted in increased resistance of gonococci to both crystal violet (CV) and erythromycin (ERY) as well as to the more lipophilic non-ionic detergent Triton X-100 (TX-100). However, this cross-resistance was contingent on the production of a full-length lipooligosaccharide (LOS) by the recipient strain used in transformation experiments. Introduction of this mutation (mtrR-171) into three chemically distinct deep-rough LOS mutants by transformation resulted in a fourfold increase in resistance to TX-100 compared with a 160-fold increase in an isogenic strain producing a full-length LOS. However, both wild-type and deep-rough LOS strains exhibited an eightfold increase in resistance to CV and ERY as a result of the mtrR-171 mutation. This suggests that gonococci have different LOS structural requirements for mtr-mediated resistance to HAs that differ in their lipophilic properties. Evidence is presented that gonococci exclude HAs by an energy-dependent efflux process mediated by the mtr system.
Collapse
Affiliation(s)
- C E Lucas
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | | | | | | | | |
Collapse
|
17
|
Drazek ES, Stein DC, Deal CD. A mutation in the Neisseria gonorrhoeae rfaD homolog results in altered lipooligosaccharide expression. J Bacteriol 1995; 177:2321-7. [PMID: 7730260 PMCID: PMC176887 DOI: 10.1128/jb.177.9.2321-2327.1995] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The gonococcal lsi-6 locus was cloned and shown by DNA sequence analysis to have homology with the E. coli rfaD gene, which encodes ADP-L-glycero-D-mannoheptose epimerase. This enzyme is involved in the biosynthesis of the lipopolysaccharide precursor ADP-L-glycero-D-mannoheptose. A site-directed frameshift mutation in lsi-6 was constructed by PCR amplification and introduced into the chromosome of Neisseria gonorrhoeae MS11 P+ by transformation. The lipooligosaccharides (LOS) of mutant and parental strains were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The lsi-6 mutant produced LOS components with apparent molecular masses of 2.6 and 3.6 kDa as compared with a 3.6-kDa band of the MS11 P+ strain. The parental LOS phenotype was expressed when a revertant was constructed by transformation of the cloned wild-type gene into the lsi-6 mutant. The immunoreactivity of LOS from parental and constructed strains was examined by SDS-PAGE and Western blotting. Only the parental and reconstructed wild-type strains produced a 3.6-kDa LOS component that reacted with monoclonal antibody 2-1-L8. These results suggest that the lsi-6 locus is involved in gonococcal LOS biosynthesis and that the nonreactive mutant 3.6-kDa LOS component contains a conformational change or altered saccharide composition that interferes with immunoreactivity.
Collapse
Affiliation(s)
- E S Drazek
- Department of Bacterial Diseases, Walter Reed Army Institute of Research, Washington, D.C. 20307-5100, USA
| | | | | |
Collapse
|