Antigenic Variation During Infection with Neisseria gonorrhoeae: Detection of Antibodies to Surface Proteins in Sera of Patients with Gonorrhea

1984 ◽  
Vol 149 (2) ◽  
pp. 166-174 ◽  
Author(s):  
K. Zak ◽  
J.- L. Diaz ◽  
D. Jackson ◽  
J. E. Heckels
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Antigenic Variation ◽  
Surface Proteins

scholarly journals Neisseria gonorrhoeae MutS Affects Pilin Antigenic Variation through Mismatch Correction and Not bypilEGuanine Quartet Binding

2015 ◽  
Vol 197 (10) ◽  
pp. 1828-1838 ◽  
Author(s):  
Ella Rotman ◽  
H. Steven Seifert
Keyword(s):  
Homologous Recombination ◽  
Neisseria Gonorrhoeae ◽  
Antigenic Variation ◽  
Synthetic Lethality ◽  
Phase Variation ◽  
Surface Proteins ◽  
Loss Of Function ◽  
Content Type ◽  
Mismatch Correction ◽  
Guanine Quartet

ABSTRACTMany pathogens use homologous recombination to vary surface antigens to avoid immune surveillance.Neisseria gonorrhoeaeachieves this in part by changing the properties of its surface pili in a process called pilin antigenic variation (AV). Pilin AV occurs by high-frequency gene conversion reactions that transfer silentpilSsequences into the expressedpilElocus and requires the formation of an upstream guanine quartet (G4) DNA structure to initiate this process. The MutS and MutL proteins of the mismatch correction (MMC) system act to correct mismatches after replication and prevent homeologous (i.e., partially homologous) recombination, but MutS orthologs can also bind to G4 structures. A previous study showed that mutation of MutS resulted in a 3-fold increase in pilin AV, which could be due to the loss of MutS antirecombination properties or loss of G4 binding. We tested two site-directed separation-of-function MutS mutants that are both predicted to bind to G4s but are not able to perform MMC. Pilus phase variation assays and DNA sequence analysis ofpilEvariants produced in these mutants showed that all threemutSmutants and amutLmutant had similar increased frequencies of pilin AV. Moreover, themutSmutants all showed similar increased levels of pilin AV-dependent synthetic lethality. These results show that antirecombination by MMC is the reason for the effect that MutS has on pilin AV and is not due topilEG4 binding by MutS.IMPORTANCENeisseria gonorrhoeaecontinually changes its outer surface proteins to avoid recognition by the immune system.N. gonorrhoeaealters the antigenicity of the pilus by directed recombination between partially homologous pilin copies in a process that requires a guanine quartet (G4) structure. The MutS protein of the mismatch correction (MMC) system prevents recombination between partially homologous sequences and can also bind to G4s. We confirmed that loss of MMC increases the frequency of pilin antigenic variation and that two MutS mutants that are predicted to separate the two different functions of MutS inhibit pilin variation similarly to a complete-loss-of-function mutant, suggesting that interaction of MutS with the G4 structure is not a major factor in this process.

scholarly journals PacBio Amplicon Sequencing Method To Measure Pilin Antigenic Variation Frequencies of Neisseria gonorrhoeae

mSphere ◽  
2019 ◽  
Vol 4 (5) ◽  
Author(s):  
Egon A. Ozer ◽  
Lauren L. Prister ◽  
Shaohui Yin ◽  
Billy H. Ward ◽  
Stanimir Ivanov ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Antigenic Variation ◽  
Amplicon Sequencing ◽  
Common Mechanism ◽  
Macrophage Infection ◽  
Gene Encoding ◽  
Transmitted Infection ◽  
Variable Regions ◽  
Content Type ◽  
Strain Fa1090

ABSTRACT Gene diversification is a common mechanism pathogens use to alter surface structures to aid in immune avoidance. Neisseria gonorrhoeae uses a gene conversion-based diversification system to alter the primary sequence of the gene encoding the major subunit of the pilus, pilE. Antigenic variation occurs when one of the nonexpressed 19 silent copies donates part of its DNA sequence to pilE. We have developed a method using Pacific Biosciences (PacBio) amplicon sequencing and custom software to determine pilin antigenic variation frequencies. The program analyzes 37 variable regions across the strain FA1090 1-81-S2 pilE gene and can be modified to determine sequence variation from other starting pilE sequences or other diversity generation systems. Using this method, we measured pilin antigenic variation frequencies for various derivatives of strain FA1090 and showed we can also analyze pilin antigenic variation frequencies during macrophage infection. IMPORTANCE Diversity generation systems are used by many unicellular organism to provide subpopulations of cell with different properties that are available when needed. We have developed a method using the PacBio DNA sequencing technology and a custom computer program to analyze the pilin antigenic variation system of the organism that is the sole cause of the sexually transmitted infection, gonorrhea.

scholarly journals A Double-Strand Break Does Not PromoteNeisseria gonorrhoeaePilin Antigenic Variation

2019 ◽  
Vol 201 (13) ◽  
Author(s):  
Lauren L. Prister ◽  
Jing Xu ◽  
H Steven Seifert
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Antigenic Variation ◽  
Dna Structure ◽  
Strand Break ◽  
Double Strand Break ◽  
Content Type ◽  
G4 Dna ◽  
Recombination System ◽  
Guanine Quadruplex ◽  
Pilin Gene

ABSTRACTThe major subunit of the type IV pilus (T4p) ofNeisseria gonorrhoeaeundergoes antigenic variation (AV) dependent on a guanine quadruplex (G4) DNA structure located upstream of the pilin gene. Since the presence of G4 DNA induces genome instability in both eukaryotic and prokaryotic chromosomes, we tested whether a double-strand break (DSB) at the site of thepilEG4 sequence could substitute for G4-directed pilin AV. The G4 motif was replaced by an I-SceI cut site, and the cut site was also introduced to locations near the origin of replication and the terminus. Expression of the I-SceI endonuclease from an irrelevant chromosomal site confirmed that the endonuclease functions to induce double-strand breaks at all three locations. No antigenic variants were detected when the G4 was replaced with the I-SceI cut site, but there was a growth defect from having a DSB in the chromosome, and suppressor mutations that were mainly deletions of the cut site and/or the entirepilEgene accumulated. Thus, thepilEG4 does not act to promote pilin AV by generating a DSB but requires either a different type of break, a nick, or more complex interactions with other factors to stimulate this programmed recombination system.IMPORTANCENeisseria gonorrhoeae, the causative agent of gonorrhea, possesses a DNA recombination system to change one of its surface-exposed antigens. This recombination system, known as antigenic variation, uses an alternate DNA structure to initiate variation. The guanine quadruplex DNA structure is known to cause nicks or breaks in DNA; however, much remains unknown about how this structure functions in cells. We show that inducing a break by different means does not allow antigenic variation, indicating that the DNA structure may have a more complicated role.

scholarly journals Comparative proteomics of three Giardia lamblia strains: investigation of antigenic variation in the post-genomic era

Parasitology ◽  
2020 ◽  
Vol 147 (9) ◽  
pp. 1008-1018 ◽  
Author(s):  
Joachim Müller ◽  
Sophie Braga ◽  
Anne-Christine Uldry ◽  
Manfred Heller ◽  
Norbert Müller
Keyword(s):  
Giardia Lamblia ◽  
Antigenic Variation ◽  
Restriction Analysis ◽  
Surface Proteins ◽  
Differentially Expressed ◽  
Laboratory Research ◽  
Persistent Diarrhoea ◽  
Reading Frame ◽  
Expression Levels ◽  
Predominant Variant

AbstractGiardia lamblia is a causative agent of persistent diarrhoea widespread in regions with low hygienic standards. Laboratory research is based on cloned lines issuing from various patient isolates typed in the late 1980s and 90s using restriction analysis and serology. In the present study, we compared the well-characterized strain WBC6 with another clone of the parent WB isolate termed WBA1 and with a clone from another isolate, GS/M-83-H7, using shotgun mass spectrometry proteomics. We identified 398 proteins differentially expressed between the GS and both WB isolates and 97 proteins differentially expressed between the two WB isolates. We investigated the expression levels of the predominant variant-specific surface proteins (VSPs) in each clone and matched the previously described major VSPs of each strain to the corresponding open reading frame sequences identified by whole-genome sequencing efforts. Furthermore, since the original WB isolate comes from a patient treated with metronidazole, we compared the susceptibilities of the strains to nitro compounds, as well the expression levels of enzymes involved in nitro reduction and on the corresponding enzyme activities and found distinct differences between the three strains.

scholarly journals Low-Phosphate-Dependent Invasion Resembles a General Way for Neisseria gonorrhoeae To Enter Host Cells

2006 ◽  
Vol 74 (7) ◽  
pp. 4266-4273 ◽  
Author(s):  
Christiane Kühlewein ◽  
Cindy Rechner ◽  
Thomas F. Meyer ◽  
Thomas Rudel
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Rho Gtpases ◽  
Wide Spectrum ◽  
Cell Types ◽  
Surface Proteins ◽  
Host Cells ◽  
Animal Origin ◽  
Target Cells ◽  
Pit Formation ◽  
Serious Disease

ABSTRACT Obligate human-pathogenic Neisseria gonorrhoeae expresses numerous variant surface proteins mediating adherence to and invasion of target cells. The invariant major outer membrane porin PorB of serotype A (P.IA) gonococci triggers invasion into Chang cells only if the medium is devoid of phosphate. Since gonococci expressing PorBIA are frequently isolated from patients with severe disseminating infections, the interaction initiated by the porin may be of major relevance for the development of this serious disease. Here, we investigated the low-phosphate-dependent invasion and compared it to the well-known pathways of entry initiated by Opa proteins. P.IA-triggered invasion requires clathrin-coated pit formation and the action of actin and Rho GTPases. However, in contrast to Opa-initiated invasion via heparan sulfate proteoglycans, microtubules, acidic sphingomyelinase, phosphatidylinositol 3-kinase, and myosin light chain kinase are not involved in this entry pathway. Nor are Src kinases required, as they are in invasion, e.g., via the CEACAM3 receptor. Invasion by PorBIA occurs in a wide spectrum of cell types, such as primary human epithelial and endothelial cells and in cancer cells of human and animal origin. Low-phosphate-dependent invasion is thus a pathway of gonococcal entry distinct from Opa-mediated invasion.

Anaplasma marginale(Rickettsiales: Anaplasmataceae): recent advances in defining host–pathogen adaptations of a tick-borne rickettsia

Parasitology ◽  
2004 ◽  
Vol 129 (S1) ◽  
pp. S285-S300 ◽  
Author(s):  
K. M. KOCAN ◽  
J. DE LA FUENTE ◽  
E. F. BLOUIN ◽  
J. C. GARCIA-GARCIA
Keyword(s):  
Antigenic Variation ◽  
Control Strategies ◽  
Anaplasma Marginale ◽  
Surface Proteins ◽  
Host Cells ◽  
Developmental Cycle ◽  
Persistent Infections ◽  
Phylogenetic Studies ◽  
Major Surface Proteins ◽  
Major Surface

The tick-borne intracellular pathogenAnaplasma marginale(Rickettsiales: Anaplasmataceae) develops persistent infections in cattle and tick hosts. While erythrocytes appear to be the only site of infection in cattle,A. marginaleundergoes a complex developmental cycle in ticks and transmission occurs via salivary glands during feeding. Many geographic isolates occur that vary in genotype, antigenic composition, morphology and infectivity for ticks. In this chapter we review recent research on the host–vector–pathogen interactions ofA. marginale. Major surface proteins (MSPs) play a crucial role in the interaction ofA. marginalewith host cells. The MSP1a protein, which is an adhesin for bovine erythrocytes and tick cells, is differentially regulated and affects infection and transmission ofA. marginalebyDermacentorspp. ticks. MSP2 undergoes antigenic variation and selection in cattle and ticks, and contributes to the maintenance of persistent infections. Phylogenetic studies ofA. marginalegeographic isolates usingmsp4andmsp1α provide information about the biogeography and evolution ofA. marginale:msp1α genotypes evolve under positive selection pressure. Isolates ofA. marginaleare maintained by independent transmission events and a mechanism of infection exclusion in cattle and ticks allows for only the infection of one isolate per animal. Prospects for development of control strategies by use of pathogen and tick-derived antigens are discussed. TheA. marginale/vector/host studies described herein could serve as a model for research on other tick-borne rickettsiae.

scholarly journals Altering the Neisseria gonorrhoeae pilE Guanine Quadruplex Loop Bases Affects Pilin Antigenic Variation

Biochemistry ◽  
2020 ◽  
Vol 59 (10) ◽  
pp. 1104-1112
Author(s):  
Lauren L. Prister ◽  
Shaohui Yin ◽  
Laty A. Cahoon ◽  
H Steven Seifert
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Antigenic Variation ◽  
Guanine Quadruplex

scholarly journals Expressed var genes are found in Plasmodium falciparum subtelomeric regions.

1997 ◽  
Vol 17 (2) ◽  
pp. 604-611 ◽  
Author(s):  
R Hernandez-Rivas ◽  
D Mattei ◽  
Y Sterkers ◽  
D S Peterson ◽  
T E Wellems ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Antigenic Variation ◽  
Protein Product ◽  
Terminal Segment ◽  
Surface Proteins ◽  
Var Genes ◽  
Active Expression ◽  
Transmembrane Sequence ◽  
High Level ◽  
Carboxy Terminal

The antigenic variation and cytoadherence of Plasmodium falciparum-infected erythrocytes are modulated by a family of variant surface proteins encoded by the var multigene family. The var genes occur on multiple chromosomes, often in clusters, and 50 to 150 genes are estimated to be present in the haploid parasite genome. Transcripts from var genes have been previously mapped to internal chromosome positions, but the generality of such assignments and the expression sites and mechanisms that control switches of var gene expression are still in early stages of investigation. Here we describe investigations of closely related var genes that occur in association with repetitive elements near the telomeres of P. falciparum chromosomes. DNA sequence analysis of one of these genes (FCR3-varT11-1) shows the characteristic two-exon structure encoding expected var features, including three variable Duffy binding-like (DBL) domains, a transmembrane sequence, and a carboxy-terminal segment thought to anchor the protein product in knobs at the surface of the parasitized erythrocyte. FCR3-varT11-1 cross-hybridizes with var genes located close to the telomeres of many other P. falciparum chromosomes, including a transcribed gene (FCR3-varT3-1) in chromosome 3 of the P. falciparum FCR3 line. The relatively high level transcription from this gene shows that the polymorphic chromosome ends of P. falciparum, which have been proposed to be transcriptionally silent, can be active expression sites for var genes. The pattern of the FCR3-varT11-1 and FCR3-varT3-1 genes are variable between different P. falciparum lines, presumably due to DNA rearrangements. Thus, recombination events in subtelomeric DNA may have a role in the expression of novel var forms.

scholarly journals Transposon Mutagenesis Identifies Sites Upstream of the Neisseria gonorrhoeae pilE Gene That Modulate Pilin Antigenic Variation

2007 ◽  
Vol 189 (9) ◽  
pp. 3462-3470 ◽  
Author(s):  
Kimberly A. Kline ◽  
Alison K. Criss ◽  
Anne Wallace ◽  
H. Steven Seifert
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Gene Conversion ◽  
Dna Sequences ◽  
Antigenic Variation ◽  
Transposon Mutagenesis ◽  
Repeat Sequence ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Type Iv ◽  
Pilin Gene

ABSTRACT Gene conversion mediates the variation of virulence-associated surface structures on pathogenic microorganisms, which prevents host humoral immune responses from being effective. One of the best-studied gene conversion systems is antigenic variation (Av) of the pilin subunit of the Neisseria gonorrhoeae type IV pilus. To identify cis-acting DNA sequences that facilitate Av, the 700-bp region upstream of the pilin gene pilE was targeted for transposon mutagenesis. Four classes of transposon-associated mutations were isolated, distinguishable by their pilus-associated phenotypes: (i) insertions that did not alter Av or piliation, (ii) insertions that blocked Av, (iii) insertions that interfered with Av, and (iv) insertions that interfered with pilus expression and Av. Mutagenesis of the pilE promoter did not affect the frequency of Av, directly demonstrating that pilin Av is independent of pilE transcription. Two stretches of sequence upstream of pilE were devoid of transposon insertions, and some deletions in these regions were not recoverable, suggesting that they are essential for gonococcal viability. Insertions that blocked pilin Av were located downstream of the RS1 repeat sequence, and deletion of the region surrounding these insertions completely abrogated pilin Av, confirming that specific sequences 5′ to pilE are essential for the recombination events underlying pilin Av.

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