scholarly journals Posttranslational Regulation of IL-23 Production Distinguishes the Innate Immune Responses to Live Toxigenic versus Heat-Inactivated Vibrio cholerae

mSphere ◽  
2019 ◽  
Vol 4 (4) ◽  
Author(s):  
Ana A. Weil ◽  
Crystal N. Ellis ◽  
Meti D. Debela ◽  
Taufiqur R. Bhuiyan ◽  
Rasheduzzaman Rashu ◽  
...  

ABSTRACT Vibrio cholerae infection provides long-lasting protective immunity, while oral, inactivated cholera vaccines (OCV) result in more-limited protection. To identify characteristics of the innate immune response that may distinguish natural V. cholerae infection from OCV, we stimulated differentiated, macrophage-like THP-1 cells with live versus heat-inactivated V. cholerae with and without endogenous or exogenous cholera holotoxin (CT). Interleukin 23A gene (IL23A) expression was higher in cells exposed to live V. cholerae than in cells exposed to inactivated organisms (mean change, 38-fold; 95% confidence interval [95% CI], 4.0 to 42; P < 0.01). IL-23 secretion was also higher in cells exposed to live V. cholerae than in cells exposed to inactivated V. cholerae (mean change, 5.6-fold; 95% CI, 4.4 to 11; P < 0.001). This increase in IL-23 secretion was more marked than for other key innate immune cytokines (e.g., IL-1β and IL-6) and dependent on exposure to the combination of both live V. cholerae and CT. While IL-23 secretion was reduced following stimulation with either heat-inactivated wild-type V. cholerae or a live isogenic ctxAB mutant of V. cholerae, the addition of exogenous CT restored IL-23 secretion in combination with the live isogenic ctxAB mutant V. cholerae, but not when it was paired with stimulation by heat-inactivated V. cholerae. The posttranslational regulation of IL-23 under these conditions was dependent on the activity of the cysteine protease cathepsin B. In humans, IL-23 promotes the differentiation of Th17 cells to T follicular helper cells, which maintain and support long-term memory B cell generation after infection. Based on these findings, the stimulation of IL-23 production may be a determinant of protective immunity following V. cholerae infection. IMPORTANCE An episode of cholera provides better protection against reinfection than oral cholera vaccines, and the reasons for this are still under study. To better understand this, we compared the immune responses of human cells exposed to live Vibrio cholerae with those of cells exposed to heat-killed V. cholerae (similar to the contents of oral cholera vaccines). We also compared the effects of active cholera toxin and the inactive cholera toxin B subunit (which is included in some cholera vaccines). One key immune signaling molecule, IL-23, was uniquely produced in response to the combination of live bacteria and active cholera holotoxin. Stimulation with V. cholerae that did not produce the active toxin or was killed did not produce an IL-23 response. The stimulation of IL-23 production by cholera toxin-producing V. cholerae may be important in conferring long-term immunity after cholera.

2015 ◽  
Vol 198 (2) ◽  
pp. 268-275 ◽  
Author(s):  
Archana Pant ◽  
D Anbumani ◽  
Satyabrata Bag ◽  
Ojasvi Mehta ◽  
Pawan Kumar ◽  
...  

ABSTRACTThe genesis of toxigenicVibrio choleraeinvolves acquisition of CTXϕ, a single-stranded DNA (ssDNA) filamentous phage that encodes cholera toxin (CT). The phage exploits host-encoded tyrosine recombinases (XerC and XerD) for chromosomal integration and lysogenic conversion. The replicative genome of CTXϕ produces ssDNA by rolling-circle replication, which may be used either for virion production or for integration into host chromosome. Fine-tuning of different ssDNA binding protein (Ssb) levels in the host cell is crucial for cellular functioning and important for CTXϕ integration. In this study, we mutated the master regulator gene of SOS induction,lexA, ofV. choleraebecause of its known role in controlling levels of Ssb proteins in other bacteria. CTXϕ integration decreased in cells with a ΔlexAmutation and increased in cells with an SOS-noninducing mutation,lexA(Ind−). We also observed that overexpression of host-encoded Ssb (VC0397) decreased integration of CTXϕ. We propose that LexA helps CTXϕ integration, possibly by fine-tuning levels of host- and phage-encoded Ssbs.IMPORTANCECholera toxin is the principal virulence factor responsible for the acute diarrheal disease cholera. CT is encoded in the genome of a lysogenic filamentous phage, CTXϕ.Vibrio choleraehas a bipartite genome and harbors single or multiple copies of CTXϕ prophage in one or both chromosomes. Two host-encoded tyrosine recombinases (XerC and XerD) recognize the folded ssDNA genome of CTXϕ and catalyze its integration at the dimer resolution site of either one or both chromosomes. Fine-tuning of ssDNA binding proteins in host cells is crucial for CTXϕ integration. We engineered theV. choleraegenome and created several reporter strains carrying ΔlexAorlexA(Ind−) alleles. Using the reporter strains, the importance of LexA control of Ssb expression in the integration efficiency of CTXϕ was demonstrated.


2012 ◽  
Vol 19 (4) ◽  
pp. 594-602 ◽  
Author(s):  
A. A. Tarique ◽  
A. Kalsy ◽  
M. Arifuzzaman ◽  
S. M. Rollins ◽  
R. C. Charles ◽  
...  

ABSTRACTA shortcoming of currently available oral cholera vaccines is their induction of relatively short-term protection against cholera compared to that afforded by wild-type disease. We were interested in whether transcutaneous or subcutaneous boosting using a neoglycoconjugate vaccine made from a synthetic terminal hexasaccharide of the O-specific polysaccharide ofVibrio choleraeO1 (Ogawa) coupled to bovine serum albumin as a carrier (CHO-BSA) could boost lipopolysaccharide (LPS)-specific and vibriocidal antibody responses and result in protective immunity following oral priming immunization with whole-cell cholera vaccine. We found that boosting with CHO-BSA with immunoadjuvantative cholera toxin (CT) orEscherichia coliheat-labile toxin (LT) following oral priming with attenuatedV. choleraeO1 vaccine strain O395-NT resulted in significant increases in serum anti-V. choleraeLPS IgG, IgM, and IgA (P< 0.01) responses as well as in anti-Ogawa (P< 0.01) and anti-Inaba (P< 0.05) vibriocidal titers in mice. The LPS-specific IgA responses in stool were induced by transcutaneous (P< 0.01) but not subcutaneous immunization. Immune responses following use of CT or LT as an adjuvant were comparable. In a neonatal mouse challenge assay, immune serum from boosted mice was associated with 79% protective efficacy against death. Our results suggest that transcutaneous and subcutaneous boosting with a neoglycoconjugate following oral cholera vaccination may be an effective strategy to prolong protective immune responses againstV. cholerae.


mSphere ◽  
2019 ◽  
Vol 4 (6) ◽  
Author(s):  
Ana A. Weil ◽  
Rachel L. Becker ◽  
Jason B. Harris

ABSTRACT Vibrio cholerae is a noninvasive pathogen that colonizes the small intestine and produces cholera toxin, causing severe secretory diarrhea. Cholera results in long lasting immunity, and recent studies have improved our understanding of the antigenic repertoire of V. cholerae. Interactions between the host, V. cholerae, and the intestinal microbiome are now recognized as factors which impact susceptibility to cholera and the ability to mount a successful immune response to vaccination. Here, we review recent data and corresponding models to describe immune responses to V. cholerae infection and explain how the host microbiome may impact the pathogenesis of V. cholerae. In the ongoing battle against cholera, the intestinal microbiome represents a frontier for new approaches to intervention and prevention.


2021 ◽  
Vol 6 (4) ◽  
pp. 192
Author(s):  
Edward T. Ryan ◽  
Daniel T. Leung ◽  
Owen Jensen ◽  
Ana A. Weil ◽  
Taufiqur Rahman Bhuiyan ◽  
...  

Vibrio cholerae O1, the major causative agent of cholera, remains a significant public health threat. Although there are available vaccines for cholera, the protection provided by killed whole-cell cholera vaccines in young children is poor. An obstacle to the development of improved cholera vaccines is the need for a better understanding of the primary mechanisms of cholera immunity and identification of improved correlates of protection. Considerable progress has been made over the last decade in understanding the adaptive and innate immune responses to cholera disease as well as V. cholerae infection. This review will assess what is currently known about the systemic, mucosal, memory, and innate immune responses to clinical cholera, as well as recent advances in our understanding of the mechanisms and correlates of protection against V. cholerae O1 infection.


2013 ◽  
Vol 81 (12) ◽  
pp. 4626-4634 ◽  
Author(s):  
Ediane B. Silva ◽  
Andrew Goodyear ◽  
Marjorie D. Sutherland ◽  
Nicole L. Podnecky ◽  
Mercedes Gonzalez-Juarrero ◽  
...  

ABSTRACTInfections with the Gram-negative bacteriumBurkholderia pseudomallei(melioidosis) are associated with high mortality, and there is currently no approved vaccine to prevent the development of melioidosis in humans. Infected patients also do not develop protective immunity to reinfection, and some individuals will develop chronic, subclinical infections withB. pseudomallei. At present, our understanding of what constitutes effective protective immunity againstB. pseudomalleiinfection remains incomplete. Therefore, we conducted a study to elucidate immune correlates of vaccine-induced protective immunity against acuteB. pseudomalleiinfection. BALB/c and C57BL/6 mice were immunized subcutaneously with a highly attenuated, Select Agent-excludedpurMdeletion mutant ofB. pseudomallei(strain Bp82) and then subjected to intranasal challenge with virulentB. pseudomalleistrain 1026b. Immunization with Bp82 generated significant protection from challenge withB. pseudomallei, and protection was associated with a significant reduction in bacterial burden in lungs, liver, and spleen of immunized mice. Humoral immunity was critically important for vaccine-induced protection, as mice lacking B cells were not protected by immunization and serum from Bp82-vaccinated mice could transfer partial protection to nonvaccinated animals. In contrast, vaccine-induced protective immunity was found to be independent of both CD4 and CD8 T cells. Tracking studies demonstrated uptake of the Bp82 vaccine strain predominately by neutrophils in vaccine-draining lymph nodes and by smaller numbers of dendritic cells (DC) and monocytes. We concluded that protection following cutaneous immunization with a live attenuatedBurkholderiavaccine strain was dependent primarily on generation of effective humoral immune responses.


2014 ◽  
Vol 82 (10) ◽  
pp. 4204-4211 ◽  
Author(s):  
Khatoun Al Moussawi ◽  
Barbara I. Kazmierczak

ABSTRACTThe bacterial pathogenPseudomonas aeruginosacauses acute infections associated with significant morbidity and mortality.P. aeruginosaelicits strong innate immune responses in immunocompetent hosts, and the resulting recruitment of neutrophils to the site of infection is necessary for bacterial clearance.P. aeruginosalipopolysaccharide and flagellin are recognized by extracellular Toll-like receptors, but the most rapid responses to infection occur when cytosolic receptors sense flagellin or type 3 secretion system (T3SS) structural proteins. The subsequent activation of the NLRC4 inflammasome and caspase-1 generates an interleukin-1β (IL-1β) signal that is required for the rapid neutrophilic response. A T3SS effector, exotoxin U (ExoU), can inhibit activation of the NLRC4 inflammasome and caspase-1. Thus, our observation that IL-1 receptor (IL-1R)-mediated signals were still required to initiate a response to ExoU-producing bacteria was unexpected. As both IL-1α and IL-1β signal via the IL-1R, we examined immune responses in mice lacking either of these cytokines. IL-1β-deficient mice responded to ExoU-producingP. aeruginosabacteria similarly to wild-type animals; however, IL-1α-deficient mice had an attenuated immune response. The situation was reversed following infections by ExoU-negative bacteria: here, IL-1α was dispensable for neutrophil recruitment, while IL-1β was required. IL-1α secretion by macrophages infected with ExoU-producingP. aeruginosaisolates was independent of both caspase-1 and caspase-11. This study documents distinct roles for IL-1α and IL-1β in the response toP. aeruginosainfection as a function of the T3SS effectors produced by the infecting strain. The redundancy of these two cytokines nonetheless allows the infected host to mount a response to ExoU-positive and -negative bacterial isolates.


2012 ◽  
Vol 80 (12) ◽  
pp. 4417-4425 ◽  
Author(s):  
Xiaogang Wang ◽  
Philip R. Hardwidge

ABSTRACTThe NF-κB pathway regulates innate immune responses to infection. NF-κB is activated after pathogen-associated molecular patterns are detected, leading to the induction of proinflammatory host responses. As a countermeasure, bacterial pathogens have evolved mechanisms to subvert NF-κB signaling. EnterotoxigenicEscherichia coli(ETEC) causes diarrheal disease and significant morbidity and mortality for humans in developing nations. The extent to which this important pathogen subverts innate immune responses by directly targeting the NF-κB pathway is an understudied topic. Here we report that ETEC secretes a heat-stable, proteinaceous factor that blocks NF-κB signaling normally induced by tumor necrosis factor (TNF), interleukin-1β, and flagellin. Pretreating intestinal epithelial cells with ETEC supernatant significantly blocked the degradation of the NF-κB inhibitor IκBα without affecting IκBα phosphorylation. Data from immunoprecipitation experiments suggest that the ETEC factor functions by preventing IκBα polyubiquitination. Inhibiting clathrin function blocked the activity of the secreted ETEC factor, suggesting that this yet-uncharacterized activity may utilize clathrin-dependent endocytosis to enter host cells. These data suggest that ETEC evades the host innate immune response by directly modulating NF-κB signaling.


Vaccines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 33
Author(s):  
Shang-Pin Liu ◽  
Shu-Chun Chuang ◽  
Chung-Da Yang

The peptide adjuvant, pleurocidin (PLE), and the Vibrio harveyi antigen, recombinant glyceraldehyde-3-phosphate dehydrogenase (rGAPDH) protein, were encapsulated with poly (lactide-co-glycolide) (PLG) polymers in our previous study to produce PLG-encapsulated PLE plus rGAPDH microparticles (PLG-PLE/rGAPDH MPs) that sustained stable release of both PLE and rGAPDH as well as, after two-time vaccination with MPs, generated long-term protective immunity against V. harveyi in grouper. Stable controlled-release of PLE plus rGAPDH from PLG-PLE/rGAPDH MPs is an attractive feature for developing an effective single-dose vaccine. In the present study, therefore, we aim to evaluate whether single administration with PLG-PLE/rGAPDH MPs in grouper would result in protective immunity against V. harveyi. Peritoneal vaccination of grouper with one dose of PLG-PLE/rGAPDH MPs raised serum titers over a long 12-week period. Moreover, twelve weeks after vaccination, significant lymphocyte proliferation and maximum TNF-α production were found in grouper immunized with a single dose of PLG-PLE/rGAPDH MPs. More importantly, immune responses elicited by single vaccination with PLG-PLE/rGAPDH MPs protected 80% of fish against a lethal peritoneal challenge of the highly virulent V. harveyi (Vh MML-1). In conclusion, our data truly reveal the feasibility of the development of a single-dose vaccine against V. harveyi based on PLG-PLE/rGAPDH MPs.


mSystems ◽  
2019 ◽  
Vol 4 (6) ◽  
Author(s):  
Dalong Hu ◽  
Zhiqiu Yin ◽  
Chao Yuan ◽  
Pan Yang ◽  
Chengqian Qian ◽  
...  

ABSTRACT The 7th cholera pandemic began in 1961 in Sulawesi, Indonesia, and then spread around the world in at least three waves. However, the lack of genome sequences for Vibrio cholerae strains under long-term surveillance in East Asia, especially in China, has restricted our understanding of the dynamics of the intracountry and intercountry evolution and transmission of the 7th-pandemic clones. In this study, we obtained the genome sequences of 60 V. cholerae strains isolated in Shanghai, the largest port in the world and the largest city in China, from 1961 to 2011. Our whole-genome-based phylogeny of 7th-pandemic strains revealed that all but one fell into five “stages,” most of which are single clades and share independent ancestors. Each stage dominated in succession for a period, with little overlap between them. In addition, two near-identical Shanghai strains belonging to a pre-7th-pandemic precursor and 4 nontoxigenic O1/O139 strains attributed to independent recombination events at the O-antigen loci were present. The major lineages of the 7th pandemic in Shanghai appeared to be closely related to V. cholerae strains isolated from South or Southeast Asia. Stage succession was consistently related to changes in society and human activity, implying that human-caused niche change may play a vital role in the cholera dynamics in Shanghai. IMPORTANCE V. cholerae is the causative agent of cholera, a life-threatening disease characterized by severe, watery diarrhea. The 7th pandemic started in Indonesia in 1961 and spread globally, currently infecting 1.3 million to 4 million people annually. Here, we applied whole-genome sequencing to analyze a long-term collection of V. cholerae clinical strains to reveal the phylogenetic background and evolutionary dynamics of the 7th pandemic in Shanghai, which had undergone breathtakingly rapid development in the last half-century. All but one of the Shanghai 7th-pandemic strains fell into five “stages” that were dominant in Shanghai and appeared to be closely related to 7th-pandemic strains of South or Southeast Asia. Our findings extended the understanding of the dynamics of the evolution and transmission of the 7th-pandemic clones in East Asia and the relationship between social changes and cholera epidemiology.


mBio ◽  
2020 ◽  
Vol 11 (6) ◽  
Author(s):  
Daichi Morita ◽  
Masatomo Morita ◽  
Munirul Alam ◽  
Asish K. Mukhopadhyay ◽  
Fatema-tuz Johura ◽  
...  

ABSTRACT Vibrio cholerae serogroup O1 is responsible for epidemic and pandemic cholera and remains a global public health threat. This organism has been well established as a resident flora of the aquatic environment that alters its phenotypic and genotypic attributes for better adaptation to the environment. To reveal the diversity of clinical isolates of V. cholerae O1 in the Bay of Bengal, we performed whole-genome sequencing of isolates from Kolkata, India, and Dhaka, Bangladesh, collected between 2009 and 2016. Comparison with global isolates by phylogenetic analysis placed the current isolates in two Asian lineages, with lineages 1 and 2 predominant in Dhaka and Kolkata, respectively. Each lineage possessed different genetic traits in the cholera toxin B subunit gene, Vibrio seventh pandemic island II, integrative and conjugative element, and antibiotic-resistant genes. Thus, although recent global transmission of V. cholerae O1 from South Asia has been attributed only to isolates of lineage 2, another distinct lineage exists in Bengal. IMPORTANCE Cholera continues to be a global concern, as large epidemics have occurred recently in Haiti, Yemen, and countries of sub-Saharan Africa. A single lineage of Vibrio cholerae O1 has been considered to be introduced into these regions from South Asia and to cause the spread of cholera. Using genomic epidemiology, we showed that two distinct lineages exist in Bengal, one of which is linked to the global lineage. The other lineage was found only in Iran, Iraq, and countries in Asia and differed from the global lineage regarding cholera toxin variant and drug resistance profile. Therefore, the potential transmission of this lineage to other regions would likely cause worldwide cholera spread and may result in this lineage replacing the current global lineage.


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