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Frontiers in Genetics 2024has been recognized as the second most prevalent pathogen associated with diarrhea that contains blood, contributing to 12.9% of reported cases, and it is additionally...
has been recognized as the second most prevalent pathogen associated with diarrhea that contains blood, contributing to 12.9% of reported cases, and it is additionally responsible for approximately 200,000 deaths each year. Currently, there is no licensed vaccine. Multidrug resistance in all spp. is a growing concern. Current vaccines, such as O-polysaccharide (OPS) conjugates, are in clinical trials but are ineffective in children but protective in adults. Thus, innovative treatments and vaccines are needed to combat antibiotic resistance. In this study, we used immuno-informatics to design a new multiepitope vaccine and identified strain SD197's membrane protein targets using methods. The target protein was prioritized using membrane protein topology analysis to find membrane proteins. B and T-cell epitopes were predicted for vaccine formulation. The epitopes were shortlisted based on an IC50 value <50, antigenicity, allergenicity, and a toxicity analysis. In the final vaccine construct, a total of 8 B-cell epitopes, 12 MHC Class I epitopes, and 7 MHC Class II epitopes were identified for the Lipopolysaccharide export system permease protein LptF. Additionally, 17 MHC Class I epitopes and 14 MHC Class II epitopes were predicted for the Lipoprotein-releasing ABC transporter permease subunit LolE. These epitopes were selected and linked via KK, AAY, and GGGS linkers, respectively. To enhance the immunogenic response, RGD (arginine-glycine-aspartate) adjuvant was incorporated into the final vaccine construct. The refined vaccine structure exhibits a Ramachandran score of 91.5% and demonstrates stable interaction with TLR4. Normal Mode Analysis (NMA) reveals low eigenvalues (3.925996e-07), indicating steady and flexible molecular mobility of docked complexes. Codon optimization was carried out in an effective microbial expression system of the K12 strain using the recombinant plasmid pET-28a (+). Finally, the entire analysis suggests that the suggested vaccine may induce a significant immune response against , making it a promising option for additional experimental trials.
PubMed: 38826807
DOI: 10.3389/fgene.2024.1361610 -
Frontiers in Immunology 2024is the etiologic agent of a bacillary dysentery known as shigellosis, which causes millions of infections and thousands of deaths worldwide each year due to 's unique...
INTRODUCTION
is the etiologic agent of a bacillary dysentery known as shigellosis, which causes millions of infections and thousands of deaths worldwide each year due to 's unique lifestyle within intestinal epithelial cells. Cell adhesion/invasion assays have been extensively used not only to identify targets mediating host-pathogen interaction, but also to evaluate the ability of -specific antibodies to reduce virulence. However, these assays are time-consuming and labor-intensive and fail to assess differences at the single-cell level.
OBJECTIVES AND METHODS
Here, we developed a simple, fast and high-content method named visual Adhesion/Invasion Inhibition Assay (vAIA) to measure the ability of anti-antibodies to inhibit bacterial adhesion to and invasion of epithelial cells by using the confocal microscope Opera Phenix.
RESULTS
We showed that vAIA performed well with a pooled human serum from subjects challenged with and that a specific anti-IpaD monoclonal antibody effectively reduced bacterial virulence in a dose-dependent manner.
DISCUSSION
vAIA can therefore inform on the functionality of polyclonal and monoclonal responses thereby supporting the discovery of pathogenicity mechanisms and the development of candidate vaccines and immunotherapies. Lastly, this assay is very versatile and may be easily applied to other species or serotypes and to different pathogens.
Topics: Humans; Bacterial Adhesion; Dysentery, Bacillary; Antibodies, Bacterial; Host-Pathogen Interactions; Shigella; Epithelial Cells; Shigella sonnei; Antibodies, Monoclonal; HeLa Cells
PubMed: 38680489
DOI: 10.3389/fimmu.2024.1374293 -
Vaccines Mar 2024Nanoparticles (NPs) have been widely utilized in vaccine design. Although numerous NPs have been explored, NPs with adjuvant effects on their own have rarely been...
Nanoparticles (NPs) have been widely utilized in vaccine design. Although numerous NPs have been explored, NPs with adjuvant effects on their own have rarely been reported. We produce a promising self-assembled NP by integrating the pentameric heat-labile enterotoxin B subunit (LTB) (studied as a vaccine adjuvant) with a trimer-forming peptide. This fusion protein can self-assemble into the NP during expression, and polysaccharide antigens (OPS) are then loaded in vivo using glycosylation. We initially produced two A conjugate nanovaccines using two LTB subfamilies (LTIB and LTIIbB). After confirming their biosafety in mice, the data showed that both nanovaccines (NP(LTIB)-OPS and NP(LTIIbB)-OPS) elicited strong polysaccharide-specific antibody responses, and NP(LTIB)-OPS resulted in better protection. Furthermore, polysaccharides derived from or were loaded onto NP(LTIB) and NP(LTIIbB). The animal experimental results indicated that LTIB, as a pentamer module, exhibited excellent protection against lethal infections. This effect was also consistent with that of the reported cholera toxin B subunit (CTB) modular NP in all three models. For the first time, we prepared a novel promising self-assembled NP based on LTIB. In summary, these results indicated that the LTB-based nanocarriers have the potential for broad applications, further expanding the library of self-assembled nanocarriers.
PubMed: 38675730
DOI: 10.3390/vaccines12040347 -
Pharmaceutics Apr 2024Shigellosis is one of the leading causes of diarrheal disease in low- and middle-income countries, particularly in young children, and is more often associated with...
Shigellosis is one of the leading causes of diarrheal disease in low- and middle-income countries, particularly in young children, and is more often associated with antimicrobial resistance. Therefore, a preventive vaccine against shigellosis is an urgent medical need. We have proposed Generalised Modules for Membrane Antigens (GMMA) as an innovative delivery system for O-antigen, and an Alhydrogel formulation (1790GAHB) has been extensively tested in preclinical and clinical studies. Alhydrogel has been used as an adsorbent agent with the main purpose of reducing potential GMMA systemic reactogenicity. However, the immunogenicity and systemic reactogenicity of this GMMA-based vaccine formulated with or without Alhydrogel have never been compared. In this work, we investigated the potential adjuvant effect of aluminium salt-based adjuvants (Alhydrogel and AS37) on GMMA immunogenicity in mice and rabbits, and we found that GMMA alone resulted to be strongly immunogenic. The addition of neither Alhydrogel nor AS37 improved the magnitude or the functionality of vaccine-elicited antibodies. Interestingly, rabbits injected with either GMMA adsorbed on Alhydrogel or GMMA alone showed a limited and transient body temperature increase, returning to baseline values within 24 h after each vaccination. Overall, immunisation with unadsorbed GMMA did not raise any concern for animal health. We believe that these data support the clinical testing of GMMA formulated without Alhydrogel, which would allow for further simplification of GMMA-based vaccine manufacturing.
PubMed: 38675229
DOI: 10.3390/pharmaceutics16040568 -
International Journal of Molecular... Apr 2024Shigellosis is a severe gastrointestinal disease that annually affects approximately 270 million individuals globally. It has particularly high morbidity and mortality... (Review)
Review
Shigellosis is a severe gastrointestinal disease that annually affects approximately 270 million individuals globally. It has particularly high morbidity and mortality in low-income regions; however, it is not confined to these regions and occurs in high-income nations when conditions allow. The ill effects of shigellosis are at their highest in children ages 2 to 5, with survivors often exhibiting impaired growth due to infection-induced malnutrition. The escalating threat of antibiotic resistance further amplifies shigellosis as a serious public health concern. This review explores pathology, with a primary focus on the status of vaccine candidates. These candidates include killed whole-cells, live attenuated organisms, LPS-based, and subunit vaccines. The strengths and weaknesses of each vaccination strategy are considered. The discussion includes potential immunogens, such as LPS, conserved T3SS proteins, outer membrane proteins, diverse animal models used in vaccine research, and innovative vaccine development approaches. Additionally, this review addresses ongoing challenges that necessitate action toward advancing effective prevention and control measures.
Topics: Humans; Shigella Vaccines; Dysentery, Bacillary; Animals; Shigella; Vaccines, Subunit; Vaccine Development; Vaccines, Attenuated
PubMed: 38673913
DOI: 10.3390/ijms25084329 -
The American Journal of Tropical... Jun 2024This study examined the relative proportion of enteric pathogens associated with severe gastroenteritis (GE) among children younger than 2 years in a phase III efficacy... (Randomized Controlled Trial)
Randomized Controlled Trial
This study examined the relative proportion of enteric pathogens associated with severe gastroenteritis (GE) among children younger than 2 years in a phase III efficacy trial of the ROTASIIL® vaccine in India, evaluated the impact of co-infections on vaccine efficacy (VE), and characterized the association between specific pathogens and the clinical profile of severe GE. Stored stool samples collected from cases of severe GE in the phase III trial were tested by quantitative polymerase chain reaction using TaqMan™ Array Cards. Etiology was attributed by calculating the adjusted attributable fraction (AF) for each pathogen. A test-negative design was used to estimate VE. The pathogens with the highest AFs for severe diarrhea were rotavirus (23.5%), adenovirus 40/41 (17.0%), Shigella spp./enteroinvasive Escherichia coli, norovirus GII, enterotoxigenic E. coli, and Cryptosporidium spp. A considerable proportion of the disease in these children could not be explained by the pathogens tested. Severe GE cases associated with rotavirus and Shigella spp. were more likely to have a longer duration of vomiting and diarrhea, respectively. Cases attributed to Cryptosporidium spp. were more severe and required hospitalization. In the intention-to-treat population, VE was estimated to be 43.9% before and 46.5% after adjustment for co-infections; in the per-protocol population, VE was 46.7% before and 49.1% after adjustments. Rotavirus continued to be the leading cause of severe GE in this age group. The adjusted VE estimates obtained did not support co-infections as a major cause of lower vaccine performance in low- and middle-income countries.
Topics: Humans; Rotavirus Vaccines; Infant; Gastroenteritis; Rotavirus Infections; Diarrhea; Coinfection; Rotavirus; Female; Vaccine Efficacy; Shigella; Male; India; Feces; Vaccines, Attenuated; Norovirus; Enterotoxigenic Escherichia coli
PubMed: 38626750
DOI: 10.4269/ajtmh.23-0348 -
Vaccines Feb 2024is a leading cause of moderate-to-severe diarrhea globally, with young children most affected. The burden of shigellosis drops increasingly with age, inferring the...
BACKGROUND
is a leading cause of moderate-to-severe diarrhea globally, with young children most affected. The burden of shigellosis drops increasingly with age, inferring the acquisition of natural immunity. We tested the hypothesis that IgG antibodies elicited against O-specific polysaccharide (O-SP) are correlates of age-acquired immunity.
OBJECTIVES
We examined levels and determinants of serum IgG to LPS and the association with the incidence of shigellosis in Israeli children and adolescents.
METHODS
We analyzed 1096 serum samples from 0- to 19-year-olds collected in 2008-2015 for IgG anti- LPS levels by ELISA. Corresponding age-specific incidences of culture-proven shigellosis from 2008 to 2015 were obtained. We compared ecologically IgG levels, prevalence above a proposed protective threshold, and shigellosis incidence.
RESULTS
In a multivariable analysis model, children aged 1-4, 5-14, and 15-19 years were 6.71, 27.68, and 48.62 times more likely to have IgG anti- LPS above the threshold than those aged < 1 year, respectively ( < 0.001). Infants 0-3 months old had relatively high IgG anti- LPS levels of maternal origin that dropped thereafter. Children of low socioeconomic status had a 2.73 times higher likelihood of having IgG anti- LPS above the threshold ( < 0.001). A significant inverse correlation between age-specific IgG anti- LPS levels and shigellosis incidence was observed (Spearman rho= -0.76, = 0.028).
CONCLUSIONS
The study results support anti- LPS antibodies as correlates of protection that can inform vaccine development.
PubMed: 38543873
DOI: 10.3390/vaccines12030239 -
Open Forum Infectious Diseases Mar 2024is a leading cause of acute watery diarrhea, dysentery, and diarrhea-attributed linear growth faltering, a precursor to stunting and lifelong morbidity. Several...
BACKGROUND
is a leading cause of acute watery diarrhea, dysentery, and diarrhea-attributed linear growth faltering, a precursor to stunting and lifelong morbidity. Several promising vaccines are in development and field efficacy trials will require a consortium of potential vaccine trial sites with up-to-date diarrhea incidence data.
METHODS
The Enterics for Global Health (EFGH) surveillance study will employ facility-based enrollment of diarrhea cases aged 6-35 months with 3 months of follow-up to establish incidence rates and document clinical, anthropometric, and financial consequences of diarrhea at 7 country sites (Mali, Kenya, The Gambia, Malawi, Bangladesh, Pakistan, and Peru). Over a 24-month period between 2022 and 2024, the EFGH study aims to enroll 9800 children (1400 per country site) between 6 and 35 months of age who present to local health facilities with diarrhea. species (spp.) will be identified and serotyped from rectal swabs by conventional microbiologic methods and quantitative polymerase chain reaction. spp. isolates will undergo serotyping and antimicrobial susceptibility testing. Incorporating population and healthcare utilization estimates from contemporaneous household sampling in the catchment areas of enrollment facilities, we will estimate diarrhea incidence rates.
CONCLUSIONS
This multicountry surveillance network will provide key incidence data needed to design vaccine trials and strengthen readiness for potential trial implementation. Data collected in EFGH will inform policy makers about the relative importance of this vaccine-preventable disease, accelerating the time to vaccine availability and uptake among children in high-burden settings.
PubMed: 38532963
DOI: 10.1093/ofid/ofad664 -
Open Forum Infectious Diseases Mar 2024In 2002, the Centre pour le Développement des Vaccins du Mali (CVD-Mali) was established as a partnership between the Mali Ministry of Health and the University of...
BACKGROUND
In 2002, the Centre pour le Développement des Vaccins du Mali (CVD-Mali) was established as a partnership between the Mali Ministry of Health and the University of Maryland, Baltimore. Since its creation, CVD-Mali has been dedicated to describing the epidemiology of infectious diseases, supporting the development of vaccines, and training a team of local researchers. CVD-Mali participated in the Global Enteric Multicenter Study from 2007 to 2010 and the Vaccine Impact on Diarrhea in Africa study from 2015 to 2018, where the importance of as an enteric pathogen was established.
METHODS
In the Enterics for Global Health (EFGH) surveillance study, CVD-Mali will conduct surveillance at 4 health centers serving the population currently participating in a demographic surveillance system and will measure the local incidence of diarrhea and related outcomes in 6- to 35-month-old children. Antibiotic sensitivity patterns and the costs related to these cases will also be measured.
RESULTS
We anticipate reporting the number of diarrhea episodes that are positive by stool culture, the antibiotic susceptibility of these isolates, and the management and outcomes of these cases.
CONCLUSIONS
In Mali, the EFGH study will contribute valuable information to understanding the burden of in this population. These data will inform the evaluation of vaccine candidates.
PubMed: 38532954
DOI: 10.1093/ofid/ofae003 -
Open Forum Infectious Diseases Mar 2024is a major cause of diarrhea in young children worldwide. Multiple vaccines targeting are in development, and phase 3 clinical trials are imminent to determine...
BACKGROUND
is a major cause of diarrhea in young children worldwide. Multiple vaccines targeting are in development, and phase 3 clinical trials are imminent to determine efficacy against shigellosis.
METHODS
The Enterics for Global Health (EFGH) surveillance study is designed to determine the incidence of medically attended shigellosis in 6- to 35-month-old children in 7 resource-limited settings. Here, we describe the microbiological methods used to isolate and identify . We developed a standardized laboratory protocol for isolation and identification of by culture. This protocol was implemented across all 7 sites, ensuring consistency and comparability of results. Secondary objectives of the study are to determine the antibiotic resistance profiles of , compare isolation of from rectal swabs versus whole stool, and compare isolation of following transport of rectal swabs in Cary-Blair versus a modified buffered glycerol saline transport medium.
CONCLUSIONS
Data generated from EFGH using culture methods described herein can potentially be used for microbiological endpoints in future phase 3 clinical trials to evaluate vaccines against shigellosis and for other clinical and public health studies focused on these organisms.
PubMed: 38532949
DOI: 10.1093/ofid/ofad576