scholarly journals Effect of Deletion of Genes Involved in Lipopolysaccharide Core and O-Antigen Synthesis on Virulence and Immunogenicity of Salmonella enterica Serovar Typhimurium

2011 ◽  
Vol 79 (10) ◽  
pp. 4227-4239 ◽  
Author(s):  
Qingke Kong ◽  
Jiseon Yang ◽  
Qing Liu ◽  
Praveen Alamuri ◽  
Kenneth L. Roland ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Lipid A ◽  
Outer Core ◽  
Wild Type ◽  
Core Oligosaccharide ◽  
Content Type ◽  
O Antigen ◽  
Serovar Typhimurium

ABSTRACTLipopolysaccharide (LPS) is a major virulence factor ofSalmonella entericaserovar Typhimurium and is composed of lipid A, core oligosaccharide (C-OS), and O-antigen polysaccharide (O-PS). While the functions of the gene products involved in synthesis of core and O-antigen have been elucidated, the effect of removing O-antigen and core sugars on the virulence and immunogenicity ofSalmonella entericaserovar Typhimurium has not been systematically studied. We introduced nonpolar, defined deletion mutations inwaaG(rfaG),waaI(rfaI),rfaH,waaJ(rfaJ),wbaP(rfbP),waaL(rfaL), orwzy(rfc) into wild-typeS.Typhimurium. The LPS structure was confirmed, and a number ofin vitroandin vivoproperties of each mutant were analyzed. All mutants were significantly attenuated compared to the wild-type parent when administered orally to BALB/c mice and were less invasive in host tissues. Strains with ΔwaaGand ΔwaaImutations, in particular, were deficient in colonization of Peyer's patches and liver. This deficiency could be partially overcome in the ΔwaaImutant when it was administered intranasally. In the context of an attenuated vaccine strain delivering the pneumococcal antigen PspA, all of the mutations tested resulted in reduced immune responses against PspA andSalmonellaantigens. Our results indicate that nonreversible truncation of the outer core is not a viable option for developing a live oralSalmonellavaccine, while awzymutant that retains one O-antigen unit is adequate for stimulating the optimal protective immunity to homologous or heterologous antigens by oral, intranasal, or intraperitoneal routes of administration.

scholarly journals Palmitoylation State Impacts Induction of Innate and Acquired Immunity by the Salmonella enterica Serovar TyphimuriummsbBMutant

2011 ◽  
Vol 79 (12) ◽  
pp. 5027-5038 ◽  
Author(s):  
Qingke Kong ◽  
David A. Six ◽  
Qing Liu ◽  
Lillian Gu ◽  
Kenneth L. Roland ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Lipid A ◽  
Inflammatory Responses ◽  
Outer Membrane Proteins ◽  
Acyl Chain ◽  
Wild Type ◽  
Proinflammatory Response ◽  
Content Type ◽  
Serovar Typhimurium

ABSTRACTLipopolysaccharide (LPS), composed of lipid A, core, and O-antigen, is a major virulence factor ofSalmonella entericaserovar Typhimurium, with lipid A being a major stimulator to induce the proinflammatory response via the Toll-like receptor 4 (TLR4)-MD2-CD14 pathway. WhileSalmonella msbBmutants lacking the myristate chain in lipid A were investigated widely as an anticancer vaccine, inclusion of themsbBmutation in aSalmonellavaccine to deliver heterologous antigens has not yet been investigated. We introduced themsbBmutation alone or in combination with mutations in other lipid A acyl chain modification genes encoding PagL, PagP, and LpxR into wild-typeS. entericaserovar Typhimurium. ThemsbBmutation reduced virulence, while thepagL,pagP, andlpxRmutations did not affect virulence in themsbBmutant background when administered orally to BALB/c mice. Also, all mutants exhibited sensitivity to polymyxin B but did not display sensitivity to deoxycholate. LPS derived frommsbBmutants induced less inflammatory responses in human Mono Mac 6 and murine macrophage RAW264.7 cellsin vitro. However, anmsbBmutant did not decrease the induction of inflammatory responses in mice compared to the levels induced by the wild-type strain, whereas anmsbB pagPmutant induced less inflammatory responsesin vivo. The mutations were moved to an attenuatedSalmonellavaccine strain to evaluate their effects on immunogenicity. Lipid A modification caused by themsbBmutation alone and in combination withpagL,pagP, andlpxRmutations led to higher IgA production in the vaginal tract but still retained the same IgG titer level in serum to PspA, a test antigen fromStreptococcus pneumoniae, and to outer membrane proteins (OMPs) fromSalmonella.

scholarly journals The Homolog of the Gene bstA of the BTP1 Phage from Salmonella enterica Serovar Typhimurium ST313 Is an Antivirulence Gene in Salmonella enterica Serovar Dublin

2017 ◽  
Vol 86 (1) ◽  
Author(s):  
Ana Herrero-Fresno ◽  
Irene Cartas Espinel ◽  
Malene Roed Spiegelhauer ◽  
Priscila Regina Guerra ◽  
Karsten Wiber Andersen ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Type Strain ◽  
Wild Type Strain ◽  
Luria Bertani ◽  
Wild Type ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Cattle Blood

ABSTRACTIn a previous study, a novel virulence gene,bstA, identified in aSalmonella entericaserovar Typhimurium sequence type 313 (ST313) strain was found to be conserved in all publishedSalmonella entericaserovar Dublin genomes. In order to analyze the role of this gene in the host-pathogen interaction inS. Dublin, a mutant where this gene was deleted (S. Dublin ΔbstA) and a mutant which was further genetically complemented withbstA(S. Dublin 3246-C) were constructed and tested in models ofin vitroandin vivoinfection as well as during growth competition assays in M9 medium, Luria-Bertani broth, and cattle blood. In contrast to the results obtained for a strain ofS. Typhimurium ST313, the lack ofbstAwas found to be associated with increased virulence inS. Dublin. Thus,S. Dublin ΔbstAshowed higher levels of uptake than the wild-type strain during infection of mouse and cattle macrophages and higher net replication within human THP-1 cells. Furthermore, during mouse infections,S. Dublin ΔbstAwas more virulent than the wild type following a single intraperitoneal infection and showed an increased competitive index during competitive infection assays. Deletion ofbstAdid not affect either the amount of cytokines released by THP-1 macrophages or the cytotoxicity toward these cells. The histology of the livers and spleens of mice infected with the wild-type strain and theS. Dublin ΔbstAmutant revealed similar levels of inflammation between the two groups. The gene was not important for adherence to or invasion of human epithelial cells and did not influence bacterial growth in rich medium, minimal medium, or cattle blood. In conclusion, a lack ofbstAaffects the pathogenicity ofS. Dublin by decreasing its virulence. Therefore, it might be regarded as an antivirulence gene in this serovar.

scholarly journals Terminal Deoxynucleotidyl Transferase Is Not Required for Antibody Response to Polysaccharide Vaccines againstStreptococcus pneumoniaeandSalmonella entericaSerovar Typhi

2018 ◽  
Vol 86 (9) ◽  
Author(s):  
Vivek Belde ◽  
Matthew P. Cravens ◽  
Dania Gulandijany ◽  
Justin A. Walker ◽  
Isabel Palomo-Caturla ◽  
...  
Keyword(s):  
Antibody Response ◽  
B Cell ◽  
Salmonella Enterica ◽  
Passive Immunization ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Human Infants ◽  
Content Type ◽  
Serovar Typhimurium

ABSTRACTB cell antigen receptor (BCR) diversity increases by several orders of magnitude due to the action of terminal deoxynucleotidyl transferase (TdT) during V(D)J recombination. Unlike adults, infants have limited BCR diversity, in part due to reduced expression of TdT. Since human infants and young mice respond poorly to polysaccharide vaccines, such as the pneumococcal polysaccharide vaccine Pneumovax23 and Vi polysaccharide (ViPS) ofSalmonella entericaserovar Typhi, we tested the contribution of TdT-mediated BCR diversity in response to these vaccines. We found that TdT+/−and TdT−/−mice generated comparable antibody responses to Pneumovax23 and survivedStreptococcus pneumoniaechallenge. Moreover, passive immunization of B cell-deficient mice with serum from Pneumovax23-immunized TdT+/−or TdT−/−mice conferred protection. TdT+/−and TdT−/−mice generated comparable levels of anti-ViPS antibodies and antibody-dependent, complement-mediated bactericidal activity againstS. Typhiin vitro. To test the protective immunity conferred by ViPS immunizationin vivo, TdT+/−and TdT−/−mice were challenged with a chimericSalmonella entericaserovar Typhimurium strain expressing ViPS, since mice are nonpermissive hosts forS. Typhi infection. Compared to their unimmunized counterparts, immunized TdT+/−and TdT−/−mice challenged with ViPS-expressingS. Typhimurium exhibited a significant reduction in the bacterial burden and liver pathology. These data suggest that the impaired antibody response to the Pneumovax23 and ViPS vaccines in the young is not due to limited TdT-mediated BCR diversification.

scholarly journals Salmonella enterica Serovar Typhimurium Uses PbgA/YejM To Regulate Lipopolysaccharide Assembly during Bacteremia

2019 ◽  
Vol 88 (1) ◽  
Author(s):  
Melina B. Cian ◽  
Nicole P. Giordano ◽  
Revathi Masilamani ◽  
Keaton E. Minor ◽  
Zachary D. Dalebroux
Keyword(s):  
Salmonella Enterica ◽  
Lipid A ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Transmembrane Domain ◽  
Wild Type ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Periplasmic Domain ◽  
Inner Membrane Protein ◽  
Substitution Mutations

ABSTRACT Salmonella enterica serovar Typhimurium (S. Typhimurium) relies upon the inner membrane protein PbgA to enhance outer membrane (OM) integrity and promote virulence in mice. The PbgA transmembrane domain (residues 1 to 190) is essential for viability, while the periplasmic domain (residues 191 to 586) is dispensable. Residues within the basic region (residues 191 to 245) bind acidic phosphates on polar phospholipids, like for cardiolipins, and are necessary for salmonella OM integrity. S. Typhimurium bacteria increase their OM cardiolipin concentrations during activation of the PhoPQ regulators. The mechanism involves PbgA’s periplasmic globular region (residues 245 to 586), but the biological role of increasing cardiolipins on the surface is not understood. Nonsynonymous polymorphisms in three essential lipopolysaccharide (LPS) synthesis regulators, lapB (also known as yciM), ftsH, and lpxC, variably suppressed the defects in OM integrity, rifampin resistance, survival in macrophages, and systemic colonization of mice in the pbgAΔ191–586 mutant (in which the PbgA periplasmic domain from residues 191 to 586 is deleted). Compared to the OMs of the wild-type salmonellae, the OMs of the pbgA mutants had increased levels of lipid A-core molecules, cardiolipins, and phosphatidylethanolamines and decreased levels of specific phospholipids with cyclopropanated fatty acids. Complementation and substitution mutations in LapB and LpxC generally restored the phospholipid and LPS assembly defects for the pbgA mutants. During bacteremia, mice infected with the pbgA mutants survived and cleared the bacteria, while animals infected with wild-type salmonellae succumbed within 1 week. Remarkably, wild-type mice survived asymptomatically with pbgA-lpxC salmonellae in their livers and spleens for months, but Toll-like receptor 4-deficient animals succumbed to these infections within roughly 1 week. In summary, S. Typhimurium uses PbgA to influence LPS assembly during stress in order to survive, adapt, and proliferate within the host environment.

scholarly journals Novel Salmonella enterica Serovar Typhimurium Protein That Is Indispensable for Virulence and Intracellular Replication

2001 ◽  
Vol 69 (12) ◽  
pp. 7413-7418 ◽  
Author(s):  
Tahar van der Straaten ◽  
Angela van Diepen ◽  
Kitty Kwappenberg ◽  
Sjaak van Voorden ◽  
Kees Franken ◽  
...  
Keyword(s):  
Amino Acid ◽  
Protein Function ◽  
Salmonella Enterica ◽  
Host Cells ◽  
Wild Type ◽  
Intracellular Replication ◽  
Oxygen Intermediates ◽  
Serovar Typhimurium

ABSTRACT Upon contact with host cells, the intracellular pathogenSalmonella enterica serovar Typhimurium promotes its uptake, targeting, and survival in intracellular niches. In this process, the bacterium evades the microbicidal effector mechanisms of the macrophage, including oxygen intermediates. This study reports the phenotypic and genotypic characterization of an S. enterica serovar Typhimurium mutant that is hypersusceptible to superoxide. The susceptible phenotype is due to a MudJ insertion-inactivation of a previously undescribedSalmonella gene designated sspJ that is located between 54.4 and 64 min of the Salmonellachromosome and encodes a 392-amino-acid protein. In vivo, upon intraperitoneal injection of 104 to 107bacteria in C3H/HeN and 101 to 104 bacteria in BALB/c mice, the mutant strain was less virulent than the wild type. Consistent with this finding, during the first hour after ingestion by macrophage-like J774 and RAW264.7 cells in vitro, the intracellular killing of the strain carrying sspJ::MudJ is enhanced fivefold over that of wild-type microorganisms. Wild-type salmonellae displayed significant intracellular replication during the first 24 h after uptake, but sspJ::MudJ mutants failed to do so. This phenotype could be restored to that of the wild type by sspJ complementation. The SspJ protein is found in the cytoplasmic membrane and periplasmic space. Amino acid sequence homology analysis did reveal a leader sequence and putative pyrroloquinoline quinone-binding domains, but no putative protein function. We excluded the possibility that SspJ is a scavenger of superoxide or has superoxide dismutase activity.

scholarly journals Lipid A’s Structure Mediates Neisseria gonorrhoeae Fitness during Experimental Infection of Mice and Men

mBio ◽  
2013 ◽  
Vol 4 (6) ◽  
Author(s):  
Marcia M. Hobbs ◽  
James E. Anderson ◽  
Jacqueline T. Balthazar ◽  
Justin L. Kandler ◽  
Russell W. Carlson ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Genital Tract ◽  
Lipid A ◽  
Female Genital Tract ◽  
Treatment Strategies ◽  
Wild Type ◽  
Genital Tract Infection ◽  
Content Type

ABSTRACT Phosphoethanolamine (PEA) on Neisseria gonorrhoeae lipid A influences gonococcal inflammatory signaling and susceptibility to innate host defenses in in vitro models. Here, we evaluated the role of PEA-decorated gonococcal lipid A in competitive infections in female mice and in male volunteers. We inoculated mice and men with mixtures of wild-type N. gonorrhoeae and an isogenic mutant that lacks the PEA transferase, LptA. LptA production conferred a marked survival advantage for wild-type gonococci in the murine female genital tract and in the human male urethra. Our studies translate results from test tube to animal model and into the human host and demonstrate the utility of the mouse model for studies of virulence factors of the human-specific pathogen N. gonorrhoeae that interact with non-host-restricted elements of innate immunity. These results validate the use of gonococcal LptA as a potential target for development of novel immunoprophylactic strategies or antimicrobial treatments. IMPORTANCE Gonorrhea is one of the most common bacterial sexually transmitted infections, and increasing antibiotic resistance threatens the use of currently available antimicrobial therapies. In this work, encompassing in vitro studies and in vivo studies of animal and human models of experimental genital tract infection, we document the importance of lipid A’s structure, mediated by a single bacterial enzyme, LptA, in enhancing the fitness of Neisseria gonorrhoeae. The results of these studies suggest that novel agents targeting LptA may offer urgently needed prevention or treatment strategies for gonorrhea.

scholarly journals The enzyme phosphoglucomutase (Pgm) is required by Salmonella enterica serovar Typhimurium for O-antigen production, resistance to antimicrobial peptides and in vivo fitness

Microbiology ◽  
2009 ◽  
Vol 155 (10) ◽  
pp. 3403-3410 ◽  
Author(s):  
G. K. Paterson ◽  
D. B. Cone ◽  
S. E. Peters ◽  
D. J. Maskell
Keyword(s):  
Antimicrobial Peptides ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Live Attenuated Vaccine ◽  
Antigen Production ◽  
O Antigen ◽  
Serovar Typhimurium

The enzyme phosphoglucomutase (Pgm) catalyses the interconversion of glucose 1-phosphate and glucose 6-phosphate and contributes to glycolysis and the generation of sugar nucleotides for biosynthesis. To assess the role of this enzyme in the biology of the pathogen Salmonella enterica serovar Typhimurium we have characterized a pgm deletion mutant in strain SL1344. Compared to SL1344, SL1344 pgm had impaired growth in vitro, was deficient in the ability to utilize galactose as a carbon source and displayed reduced O-antigen polymer length. The mutant was also more susceptible to antimicrobial peptides and showed decreased fitness in the mouse typhoid model. The in vivo phenotype of SL1344 pgm indicated a role for pgm in the early stages of infection, most likely through deficient O-antigen production. Although pgm mutants in other pathogens have potential as live attenuated vaccine strains, SL1344 pgm was not sufficiently attenuated for such use.

scholarly journals Single passage in mouse organs enhances the survival and spread of Salmonella enterica

2015 ◽  
Vol 12 (113) ◽  
pp. 20150702 ◽  
Author(s):  
Richard Dybowski ◽  
Olivier Restif ◽  
Alexandre Goupy ◽  
Duncan J. Maskell ◽  
Piero Mastroeni ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Probability Generating Function ◽  
Systemic Infection ◽  
Original Method ◽  
Wild Type ◽  
Immigration Process ◽  
Serovar Typhimurium ◽  
Intravenous Inoculation

Intravenous inoculation of Salmonella enterica serovar Typhimurium into mice is a prime experimental model of invasive salmonellosis. The use of wild-type isogenic tagged strains (WITS) in this system has revealed that bacteria undergo independent bottlenecks in the liver and spleen before establishing a systemic infection. We recently showed that those bacteria that survived the bottleneck exhibited enhanced growth when transferred to naive mice. In this study, we set out to disentangle the components of this in vivo adaptation by inoculating mice with WITS grown either in vitro or in vivo . We developed an original method to estimate the replication and killing rates of bacteria from experimental data, which involved solving the probability-generating function of a non-homogeneous birth–death–immigration process. This revealed a low initial mortality in bacteria obtained from a donor animal. Next, an analysis of WITS distributions in the livers and spleens of recipient animals indicated that in vivo -passaged bacteria started spreading between organs earlier than in vitro -grown bacteria. These results further our understanding of the influence of passage in a host on the fitness and virulence of Salmonella enterica and represent an advance in the power of investigation on the patterns and mechanisms of host–pathogen interactions.

scholarly journals Role of B7 Costimulatory Molecules in Mediating Systemic and Mucosal Antibody Responses to Attenuated Salmonella enterica Serovar Typhimurium and Its Cloned Antigen

2004 ◽  
Vol 72 (10) ◽  
pp. 5824-5831 ◽  
Author(s):  
Carlos A. Garcia ◽  
Michael Martin ◽  
Suzanne M. Michalek
Keyword(s):  
Salmonella Enterica ◽  
Immunoglobulin A ◽  
Costimulatory Molecules ◽  
Antibody Responses ◽  
Wild Type ◽  
Igg Antibody ◽  
Functional Roles ◽  
Serovar Typhimurium

ABSTRACT The purpose of the present study was to evaluate the ability of an attenuated Salmonella enterica serovar Typhimurium vaccine strain to up-regulate B7-1 and B7-2 on antigen-presenting cells and to examine the functional roles these costimulatory molecules play in mediating immune responses to Salmonella and to an expressed cloned antigen, the saliva-binding region (SBR) of antigen I/II. In vitro stimulation of B cells (B220+), macrophages (CD11b+), and dendritic cells (CD11c+) with S. enterica serovar Typhimurium induced an up-regulation of B7-2 and, especially, B7-1 expression. The in vivo functional roles of B7-1, B7-2, and B7-1/2 were evaluated in BALB/c wild-type and B7-1, B7-2, and B7-1/2 knockout (KO) mice following intranasal immunization with the Salmonella expressing the cloned SBR. Differential requirements for B7-1 and B7-2 were observed upon primary and secondary immunizations. Compared to wild-type controls, B7-1 and B7-2 KO mice had reduced mucosal and systemic anti-Salmonella antibody responses after a single immunization, while only B7-1 KO mice exhibited suppressed anti-Salmonella antibody responses following the second immunization. Mucosal and systemic antibody responses to SBR were reduced following the primary immunization, whereas a compensatory role for either B7-1 or B7-2 was observed after the second immunization. B7-1/2 double KO mice failed to induce detectable levels of mucosal or systemic immunoglobulin A (IgA) or IgG antibody responses to either Salmonella or SBR. These findings demonstrate that B7-1 and B7-2 can play distinct as well as redundant roles for mediating mucosal and systemic antibody responses, which are likely dependent upon the nature of the antigen.

scholarly journals Effect of Inactivation of degS on Salmonella enterica Serovar Typhimurium In Vitro and In Vivo

2005 ◽  
Vol 73 (1) ◽  
pp. 459-463 ◽  
Author(s):  
Gary Rowley ◽  
Andrew Stevenson ◽  
Jan Kormanec ◽  
Mark Roberts
Keyword(s):  
Sigma Factor ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Wild Type ◽  
Alternative Pathways ◽  
E Coli ◽  
Mammalian Tissues ◽  
Serovar Typhimurium

ABSTRACT The alternative sigma factor (RpoE σE) enables Salmonella enterica serovar Typhimurium to adapt to stressful conditions, such as oxidative stress, nutrient deprivation, and growth in mammalian tissues. Infection of mice by Salmonella serovar Typhimurium also requires σE. In Escherichia coli, activation of the σE pathway is dependent on proteolysis of the anti-sigma factor RseA and is initiated by DegS. DegS is also important in order for E. coli to cause extraintestinal infection in mice. We constructed a degS mutant of the serovar Typhimurium strain SL1344 and compared its behavior in vitro and in vivo with those of its wild-type (WT) parent and an isogenic rpoE mutant. Unlike E. coli degS strains, the Salmonella serovar Typhimurium degS strain grew as well as the WT strain at 42°C. The degS mutant survived very poorly in murine macrophages in vitro and was highly attenuated compared with the WT strain for both the oral and parenteral routes of infection in mice. However, the degS mutant was not as attenuated as the serovar Typhimurium rpoE mutant: 100- to 1,000-fold more degS bacteria than rpoE bacteria were present in the livers and spleens of mice 24 h after intraperitoneal challenge. In most assays, the rpoE mutant was more severely affected than the degS mutant and a σE-dependent reporter gene was more active in the degS mutant than the rpoE strain. These findings indicate that degS is important for activation of the σE pathway in serovar Typhimurium but that alternative pathways for σE activation probably exist.

Sign in / Sign up

Export Citation Format

Share Document