scholarly journals Coimmunization with Two Enterotoxigenic Escherichia coli (ETEC) Fimbrial Multiepitope Fusion Antigens Induces the Production of Neutralizing Antibodies against Five ETEC Fimbriae (F4, F5, F6, F18, and F41)

2020 ◽  
Vol 86 (24) ◽  
Author(s):  
Qiangde Duan ◽  
Wenwen Wu ◽  
Shengmei Pang ◽  
Zhiming Pan ◽  
Weiping Zhang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Neutralizing Antibodies ◽  
Computational Models ◽  
Oral Vaccine ◽  
Enterotoxigenic Escherichia Coli ◽  
Economic Losses ◽  
Prevention Measures ◽  
Content Type ◽  
Vaccine Candidates ◽  
Postweaning Diarrhea

ABSTRACT Fimbriae mediate the initial adherence of enterotoxigenic Escherichia coli (ETEC) to the piglet small intestine and play an important role in development of ETEC-driven postweaning diarrhea (PWD). PWD inflicts huge economic losses on the swine industry each year, making development of alternative treatment and prevention measures for PWD essential. Vaccine candidates that induce antifimbria antibodies that block the initial attachment and colonization of ETEC pathogens with fimbriae are one approach that could help prevent PWD. In this study, we constructed two multiepitope fusion antigens (MEFAs) that carried, expressed, and displayed representative epitopes of F4, F5, F6, F18, and F41 ETEC fimbriae. These MEFAs used either the F4 major subunit FaeG or the F18 adhesive subunit FedF as a backbone. To assess the potential of these MEFAs as antifimbria vaccine candidates that could help prevent PWD, we generated computational models of the MEFAs, constructed them, and then tested their immunogenicity by using them to immunize mice. Computational modeling showed that all relevant epitopes were exposed on the MEFA surface. We found that coadministration of our MEFAs in mice successfully induced five fimbria-specific antibodies in accordance with the epitopes included in the MEFA constructs. Furthermore, the induced antibodies can significantly inhibit the ability of ETEC strains that express F4, F5, F6, F18, and F41 fimbriae to adhere to piglet small intestinal IPEC-1 and IPEC-J2 cells. Our findings indicate that the antifimbria antibodies induced by our FaeG-Fim41a-FanC-FasA and FedF-FasA-Fim41a-FanC fimbria MEFAs blocked adherence of five ETEC fimbriae, suggesting these multivalent fimbria MEFAs may be useful for developing broadly protective antifimbria vaccines against PWD caused by ETEC infections. IMPORTANCE Enterotoxigenic Escherichia coli (ETEC)-associated postweaning diarrhea (PWD) is still a leading disease in recently weaned piglets. Vaccination is considered to be the most ideal and efficacious strategy for preventing PWD. Recently, a commercialized live monovalent F4 oral vaccine and a bivalent F4/F18 oral vaccine have been demonstrated to effectively protect piglets in the F4-positive (F4+) and F18+ ETEC challenge models. However, they will not provide cross-protection against F5+, F6+, or F41+ ETEC-associated PWD cases, as they lack all five fimbria antigens. Thus, a multivalent vaccine containing all five ETEC fimbriae would be more effective in preventing ETEC-driven PWD. In this study, we designed two fimbria-targeted MEFAs using the MEFA technology, and further study demonstrated that these coadministered MEFAs in mice can induce protective antibodies against the five fimbriae expressed by ETEC. These MEFAs could be used as an efficient PWD vaccine candidate; furthermore, MEFA-based structural technology provides an alternative and promising strategy for the development of vaccines against pathogens with heterogeneous virulence factors.

scholarly journals Application of a Novel Epitope- and Structure-Based Vaccinology-Assisted Fimbria-Toxin Multiepitope Fusion Antigen of Enterotoxigenic Escherichia coli for Development of Multivalent Vaccines against Porcine Postweaning Diarrhea

2020 ◽  
Vol 86 (24) ◽  
Author(s):  
Ti Lu ◽  
Rodney A. Moxley ◽  
Weiping Zhang
Keyword(s):  
Escherichia Coli ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Enterotoxigenic Escherichia Coli ◽  
Economic Losses ◽  
Type I ◽  
Effective Prevention ◽  
Postweaning Diarrhea ◽  
Neutralizing Epitopes ◽  
Fusion Antigen

ABSTRACT Enterotoxigenic Escherichia coli (ETEC) strains producing K88 (F4) or F18 fimbriae and enterotoxins are the predominant cause of pig postweaning diarrhea (PWD). We recently identified neutralizing epitopes of fimbriae K88 and F18, heat-labile toxin (LT), heat-stable toxins type I (STa) and type II (STb), and Shiga toxin 2e (Stx2e). In this study, we explored a novel epitope- and structure-based vaccinology platform, multiepitope fusion antigen (MEFA), for PWD vaccine development. By using an epitope substitution LT toxoid, which lacks enterotoxicity but retains immunogenicity, as the backbone to present neutralizing epitopes of two ETEC fimbriae and four toxins, we generated PWD fimbria-toxin MEFA to mimic epitope native antigenicity. We then examined MEFA protein immunogenicity and evaluated MEFA application in PWD vaccine development. Mice subcutaneously immunized with PWD MEFA protein developed strong IgG responses to K88, F18, LT, and STb and moderate responses to the toxins Stx2e and STa. Importantly, MEFA-induced antibodies inhibited adherence of K88 or F18 fimbrial bacteria to pig intestinal cells and also neutralized LT, STa, STb, and Stx2e toxicity. These results indicated that PWD fimbria-toxin MEFA induced neutralizing antibodies against an unprecedent two fimbriae and four toxins and strongly suggested a potential application of this MEFA protein in developing a broadly protective PWD vaccine. IMPORTANCE ETEC-associated postweaning diarrhea (PWD) causes significant economic losses to swine producers worldwide. Currently, there is no effective prevention against PWD. A vaccine that blocks ETEC fimbriae (K88 and F18) from attaching to host receptors and prevents enterotoxins from stimulating water hypersecretion in pig small intestinal epithelial cells can effectively protect against PWD and significantly improves pig health and well-being. The fimbria-toxin MEFA generated from this study induced neutralizing antibodies against both ETEC fimbriae and all four ETEC toxins, suggesting a great potential of this fimbria-toxin MEFA in PWD vaccine development and further supporting the general application of this novel MEFA vaccinology platform for multivalent vaccine development.

scholarly journals A Multiepitope Fusion Antigen Elicits Neutralizing Antibodies against Enterotoxigenic Escherichia coli and Homologous Bovine Viral Diarrhea VirusIn Vitro

2013 ◽  
Vol 20 (7) ◽  
pp. 1076-1083 ◽  
Author(s):  
Emad A. Hashish ◽  
Chengxian Zhang ◽  
Xiaosai Ruan ◽  
David E. Knudsen ◽  
Christopher C. Chase ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Viral Infection ◽  
Neutralizing Antibodies ◽  
Cell Epitope ◽  
Enterotoxigenic Escherichia Coli ◽  
Bovine Viral Diarrhea ◽  
Content Type ◽  
Diarrhea Virus ◽  
Viral Diarrhea ◽  
Fusion Antigen

ABSTRACTDiarrhea is one of the most important bovine diseases. EnterotoxigenicEscherichia coli(ETEC) and bovine viral diarrhea virus (BVDV) are the major causes of diarrhea in calves and cattle. ETEC expressing K99 (F5) fimbriae and heat-stable type Ia (STa) toxin are the leading bacteria causing calf diarrhea, and BVDV causes diarrhea and other clinical illnesses in cattle of all ages. It is reported that maternal immunization with K99 fimbrial antigens provides passive protection to calves against K99 fimbrial ETEC and that BVDV major structural protein E2 elicits antibodies neutralizing against BVDV viral infection. Vaccines inducing anti-K99 and anti-STa immunity would protect calves more effectively against ETEC diarrhea, and those also inducing anti-E2 neutralizing antibodies would protect calves and cattle against diarrhea caused by both ETEC and BVDV. In this study, we used the ETEC K99 major subunit FanC as a backbone, genetically embedded the STa toxoid STaP12Fand the most-antigenic B-cell epitope and T-cell epitope predicted from the BVDV E2 glycoprotein into FanC for the multivalent antigen FanC-STa-E2, and examined immunogenicity of this multivalent antigen to assess vaccine potential against bovine diarrhea. Mice intraperitoneally (i.p.) immunized with this multivalent antigen developed anti-K99, anti-STa, and anti-BVDV antibodies. Moreover, elicited antibodies showed neutralization activities, as they inhibited adherence of K99 fimbrialE. coli, neutralized STa toxin, and prevented homologous BVDV viral infectionin vitro. Results from this study suggest that this multiepitope fusion antigen can potentially be developed as a vaccine for broad protection against bovine diarrhea and that the multiepitope fusion strategy may be generally applied for multivalent vaccine development against heterogeneous pathogens.

scholarly journals Immunizations with Enterotoxigenic Escherichia coli Heat-Stable Toxin Conjugates Engender Toxin-Neutralizing Antibodies in Mice That Also Cross-React with Guanylin and Uroguanylin

2019 ◽  
Vol 87 (7) ◽  
Author(s):  
Yuleima Diaz ◽  
Morten L. Govasli ◽  
Ephrem Debebe Zegeye ◽  
Halvor Sommerfelt ◽  
Hans Steinsland ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Cross Reactivity ◽  
Enterotoxigenic Escherichia Coli ◽  
Middle Income ◽  
Content Type ◽  
Endogenous Peptides ◽  
Heat Stable ◽  
Important Challenge

ABSTRACT Infection with enterotoxigenic Escherichia coli (ETEC) is a common cause of childhood diarrhea in low- and middle-income countries, as well as of diarrhea among travelers to these countries. In children, ETEC strains secreting the heat-stable toxin (ST) are the most pathogenic, and there are ongoing efforts to develop vaccines that target ST. One important challenge for ST vaccine development is to construct immunogens that do not elicit antibodies that cross-react with guanylin and uroguanylin, which are endogenous peptides involved in regulating the activity of the guanylate cyclase-C (GC-C) receptor. We immunized mice with both human ST (STh) and porcine ST (STp) chemically coupled to bovine serum albumin, and the resulting sera neutralized the toxic activities of both STh and STp. This suggests that a vaccine based on either ST variant can confer cross-protection. However, several anti-STh and anti-STp sera cross-reacted with the endogenous peptides, suggesting that the ST sequence must be altered to reduce the risk of unwanted cross-reactivity. Epitope mapping of four monoclonal anti-STh and six anti-STp antibodies, all of which neutralized both STh and STp, revealed that most epitopes appear to have at least one amino acid residue shared with guanylin or uroguanylin. Despite this, only one monoclonal antibody displayed demonstrable cross-reactivity to the endogenous peptides, suggesting that targeted mutations of a limited number of ST residues may be sufficient to obtain a safe ST-based vaccine.

scholarly journals Current Progress in Developing Subunit Vaccines against Enterotoxigenic Escherichia coli-Associated Diarrhea

2015 ◽  
Vol 22 (9) ◽  
pp. 983-991 ◽  
Author(s):  
Weiping Zhang ◽  
David A. Sack
Keyword(s):  
Escherichia Coli ◽  
Subunit Vaccine ◽  
Vaccine Development ◽  
Enterotoxigenic Escherichia Coli ◽  
Cell Vaccine ◽  
Virulence Determinants ◽  
Subunit Vaccines ◽  
Content Type ◽  
Vaccine Candidates ◽  
Colonization Factor

ABSTRACTDiarrhea continues to be a leading cause of death in children <5 years of age, and enterotoxigenicEscherichia coli(ETEC) is the most common bacterial cause of children's diarrhea. Currently, there are no available vaccines against ETEC-associated diarrhea. Whole-cell vaccine candidates have been under development but require further improvements because they provide inadequate protection and produce unwanted adverse effects. Meanwhile, a newer approach using polypeptide or subunit vaccine candidates focusing on ETEC colonization factor antigens (CFAs) and enterotoxins, the major virulence determinants of ETEC diarrhea, shows substantial promise. A conservative CFA/I adhesin tip antigen and a CFA MEFA (multiepitope fusion antigen) were shown to induce cross-reactive antiadhesin antibodies that protected against adherence by multiple important CFAs. Genetic fusion of toxoids derived from ETEC heat-labile toxin (LT) and heat-stable toxin (STa) induced antibodies neutralizing both enterotoxins. Moreover, CFA-toxoid MEFA polypeptides, generated by fusing CFA MEFA to an STa-LT toxoid fusion, induced antiadhesin antibodies that broadly inhibited adherence of the seven most important ETEC CFAs associated with about 80% of the diarrhea cases caused by ETEC strains with known CFAs. This same antigen preparation also induced antitoxin antibodies that neutralized both toxins that are associated with all cases of ETEC diarrhea. Results from these studies suggest that polypeptide or subunit vaccines have the potential to effectively protect against ETEC diarrhea. In addition, novel adhesins and mucin proteases have been investigated as potential alternatives or, more likely, additional antigens for ETEC subunit vaccine development.

scholarly journals Immunogenicity and protective efficacy of enterotoxigenic Escherichia coli (ETEC) total RNA against ETEC challenge in a mouse model

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mandi Liu ◽  
Yue Zhang ◽  
Di Zhang ◽  
Yun Bai ◽  
Guomei Liu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Mouse Model ◽  
Immune Responses ◽  
Protective Efficacy ◽  
Enterotoxigenic Escherichia Coli ◽  
Economic Losses ◽  
Th2 Response ◽  
Total Rna ◽  
Etec Infection

AbstractEnterotoxigenic Escherichia coli (ETEC), an essential cause of post-weaning diarrhea (PWD) in piglets, leads to significant economic losses to the pig industry. The present study aims to identify the role of ETEC total RNA in eliciting immune responses to protect animals against ETEC infection. The results showed that the total RNA isolated from pig-derived ETEC K88ac strain effectively stimulated the IL-1β secretion of porcine intestinal epithelial cells (IPEC-J2). The mouse model immunized with ETEC total RNA via intramuscular injection (IM) or oral route (OR) was used to evaluate the protective efficiency of the ETEC total RNA. The results suggested that 70 μg ETEC total RNA administered by either route significantly promoted the production of the serum IL-1β and K88ac specific immunoglobulins (IgG, IgM, and IgA). Besides, the ETEC RNA administration augmented strong mucosal immunity by elevating K88ac specific IgA level in the intestinal fluid. Intramuscularly administered RNA induced a Th1/Th2 shift toward a Th2 response, while the orally administered RNA did not. The ETEC total RNA efficiently protected the animals against the ETEC challenge either by itself or as an adjuvant. The histology characterization of the small intestines also suggested the ETEC RNA administration protected the small intestinal structure against the ETEC infection. Particularly of note was that the immunity level and protective efficacy caused by ETEC RNA were dose-dependent. These findings will help understand the role of bacterial RNA in eliciting immune responses, and benefit the development of RNA-based vaccines or adjuvants.

scholarly journals Immunogenicity in Swine of Orally Administered Recombinant Lactobacillus plantarum Expressing Classical Swine Fever Virus E2 Protein in Conjunction with Thymosin α-1 as an Adjuvant

2015 ◽  
Vol 81 (11) ◽  
pp. 3745-3752 ◽  
Author(s):  
Yi-Gang Xu ◽  
Xue-Ting Guan ◽  
Zhong-Mei Liu ◽  
Chang-Yong Tian ◽  
Li-Chun Cui
Keyword(s):  
Immune Responses ◽  
Lactobacillus Plantarum ◽  
Classical Swine Fever Virus ◽  
Oral Vaccine ◽  
Classical Swine Fever ◽  
Fever Virus ◽  
Economic Losses ◽  
E2 Protein ◽  
Content Type ◽  
Cellular Immune

ABSTRACTClassical swine fever, caused by classical swine fever virus (CSFV), is a highly contagious disease that results in enormous economic losses in pig industries. The E2 protein is one of the main structural proteins of CSFV and is capable of inducing CSFV-neutralizing antibodies and cytotoxic T lymphocyte (CTL) activitiesin vivo. Thymosin α-1 (Tα1), an immune-modifier peptide, plays a very important role in the cellular immune response. In this study, genetically engineeredLactobacillus plantarumbacteria expressing CSFV E2 protein alone (L. plantarum/pYG-E2) and in combination with Tα1 (L. plantarum/pYG-E2-Tα1) were developed, and the immunogenicity of each as an oral vaccine to induce protective immunity against CSFV in pigs was evaluated. The results showed that recombinantL. plantarum/pYG-E2 andL. plantarum/pYG-E2-Tα1 were both able to effectively induce protective immune responses in pigs against CSFV infection by eliciting immunoglobulin A (IgA)-based mucosal, immunoglobulin G (IgG)-based humoral, and CTL-based cellular immune responses via oral vaccination. Significant differences (P< 0.05) in the levels of immune responses were observed betweenL. plantarum/pYG-E2-Tα1 andL. plantarum/pYG-E2, suggesting a better immunogenicity ofL. plantarum/pYG-E2-Tα1 as a result of the Tα1 molecular adjuvant that can enhance immune responsiveness and augment specific lymphocyte functions. Our data suggest that the recombinantLactobacillusmicroecological agent expressing CSFV E2 protein combined with Tα1 as an adjuvant provides a promising strategy for vaccine development against CSFV.

scholarly journals Complete Genome Sequence of Enterotoxigenic Escherichia coli Podophage LL11

2019 ◽  
Vol 8 (32) ◽  
Author(s):  
Matthew Theodore ◽  
Lauren Lessor ◽  
Chandler O’Leary ◽  
Rohit Kongari ◽  
Jason Gill ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genome Sequence ◽  
Alternative Treatment ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Opportunistic Pathogen ◽  
Foodborne Illness ◽  
Enterotoxigenic Escherichia Coli ◽  
Content Type ◽  
Illness Study

Enterotoxigenic Escherichia coli (ETEC) is an opportunistic pathogen that commonly causes foodborne illness. Study of bacteriophages against this pathogen could be useful to develop alternative treatment approaches. Here, we present the complete genome sequence of LL11, a T7-like podophage that infects ETEC.

scholarly journals Complete Genome Sequence of Enterotoxigenic Escherichia coli Siphophage LL5

2019 ◽  
Vol 8 (27) ◽  
Author(s):  
Denish Piya ◽  
Lauren Lessor ◽  
Mei Liu ◽  
Jason J. Gill
Keyword(s):  
Escherichia Coli ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Enterotoxigenic Escherichia Coli ◽  
Content Type ◽  
Traveler’S Diarrhea ◽  
Traveler's Diarrhea

ABSTRACT Here, we describe the complete genome sequence of siphophage LL5. LL5 is a T1-like phage isolated against enterotoxigenic Escherichia coli, which causes traveler’s diarrhea. LL5 is included as a component phage in the commercial prebiotic product PreforPro.

scholarly journals Genomic Avenue to Avian Colisepticemia

mBio ◽  
2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Sagi Huja ◽  
Yaara Oren ◽  
Eva Trost ◽  
Elzbieta Brzuszkiewicz ◽  
Dvora Biran ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genetic Analysis ◽  
Virulence Factors ◽  
Iron Uptake ◽  
Secretion System ◽  
Economic Losses ◽  
Content Type ◽  
E Coli ◽  
Type 3 Secretion System ◽  
Type 3

ABSTRACTHere we present an extensive genomic and genetic analysis of Escherichia coli strains of serotype O78 that represent the major cause of avian colisepticemia, an invasive infection caused by avian pathogenicEscherichia coli(APEC) strains. It is associated with high mortality and morbidity, resulting in significant economic consequences for the poultry industry. To understand the genetic basis of the virulence of avian septicemic E. coli, we sequenced the entire genome of a clinical isolate of serotype O78—O78:H19 ST88 isolate 789 (O78-9)—and compared it with three publicly available APEC O78 sequences and one complete genome of APEC serotype O1 strain. Although there was a large variability in genome content between the APEC strains, several genes were conserved, which are potentially critical for colisepticemia. Some of these genes are present in multiple copies per genome or code for gene products with overlapping function, signifying their importance. A systematic deletion of each of these virulence-related genes identified three systems that are conserved in all septicemic strains examined and are critical for serum survival, a prerequisite for septicemia. These are the plasmid-encoded protein, the defective ETT2 (E. colitype 3 secretion system 2) type 3 secretion system ETT2sepsis, and iron uptake systems. Strain O78-9 is the only APEC O78 strain that also carried the regulon coding for yersiniabactin, the iron binding system of theYersiniahigh-pathogenicity island. Interestingly, this system is the only one that cannot be complemented by other iron uptake systems under iron limitation and in serum.IMPORTANCEAvian colisepticemia is a severe systemic disease of birds causing high morbidity and mortality and resulting in severe economic losses. The bacteria associated with avian colisepticemia are highly antibiotic resistant, making antibiotic treatment ineffective, and there is no effective vaccine due to the multitude of serotypes involved. To understand the disease and work out strategies to combat it, we performed an extensive genomic and genetic analysis of Escherichia coli strains of serotype O78, the major cause of the disease. We identified several potential virulence factors, conserved in all the colisepticemic strains examined, and determined their contribution to growth in serum, an absolute requirement for septicemia. These findings raise the possibility that specific vaccines or drugs can be developed against these critical virulence factors to help combat this economically important disease.

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