scholarly journals A bivalent vaccine confers immunogenicity and protection against Shigella flexneri and enterotoxigenic Escherichia coli infections in mice

npj Vaccines ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Pedro Henrique Q. S. Medeiros ◽  
David T. Bolick ◽  
Solanka E. Ledwaba ◽  
Glynis L. Kolling ◽  
Deiziane V. S. Costa ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shigella Flexneri ◽  
Enterotoxigenic Escherichia Coli ◽  
Bivalent Vaccine

scholarly journals Structure of the master regulator Rns reveals an inhibitor of enterotoxigenic Escherichia coli virulence regulons

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Charles R. Midgett ◽  
Kacey Marie Talbot ◽  
Jessica L. Day ◽  
George P. Munson ◽  
F. Jon Kull
Keyword(s):  
Escherichia Coli ◽  
Small Molecules ◽  
Family Member ◽  
Shigella Flexneri ◽  
Decanoic Acid ◽  
Enterotoxigenic Escherichia Coli ◽  
Gram Negative Bacteria ◽  
Enteric Infections ◽  
First Time ◽  
Arac Family

AbstractEnteric infections caused by the gram-negative bacteria enterotoxigenic Escherichia coli (ETEC), Vibrio cholerae, Shigella flexneri, and Salmonella enterica are among the most common and affect billions of people each year. These bacteria control expression of virulence factors using a network of transcriptional regulators, some of which are modulated by small molecules as has been shown for ToxT, an AraC family member from V. cholerae. In ETEC the expression of many types of adhesive pili is dependent upon the AraC family member Rns. We present here the 3 Å crystal structure of Rns and show it closely resembles ToxT. Rns crystallized as a dimer via an interface similar to that observed in other dimeric AraC’s. Furthermore, the structure of Rns revealed the presence of a ligand, decanoic acid, that inhibits its activity in a manner similar to the fatty acid mediated inhibition observed for ToxT and the S. enterica homologue HilD. Together, these results support our hypothesis that fatty acids regulate virulence controlling AraC family members in a common manner across a number of enteric pathogens. Furthermore, for the first time this work identifies a small molecule capable of inhibiting the ETEC Rns regulon, providing a basis for development of therapeutics against this deadly human pathogen.

scholarly journals Genetic Characterization and Immunogenicity of Coli Surface Antigen 4 from Enterotoxigenic Escherichia coli when It Is Expressed in a Shigella Live-Vector Strain

2003 ◽  
Vol 71 (3) ◽  
pp. 1352-1360 ◽  
Author(s):  
Zeev Altboum ◽  
Myron M. Levine ◽  
James E. Galen ◽  
Eileen M. Barry
Keyword(s):  
Escherichia Coli ◽  
Shigella Flexneri ◽  
Regulatory Protein ◽  
Electron Microscopic Examination ◽  
Amino Acid Sequences ◽  
Enterotoxigenic Escherichia Coli ◽  
Electron Microscopic ◽  
Bacterial Surface ◽  
Fimbrial Subunit ◽  
Mucosal Antibody

ABSTRACT The genes that encode the enterotoxigenic Escherichia coli (ETEC) CS4 fimbriae, csaA, -B, -C, -E, and -D′, were isolated from strain E11881A. The csa operon encodes a 17-kDa major fimbrial subunit (CsaB), a 40-kDa tip-associated protein (CsaE), a 27-kDa chaperone-like protein (CsaA), a 97-kDa usher-like protein (CsaC), and a deleted regulatory protein (CsaD′). The predicted amino acid sequences of the CS4 proteins are highly homologous to structural and assembly proteins of other ETEC fimbriae, including CS1 and CS2, and to CFA/I in particular. The csaA, -B, -C, -E operon was cloned on a stabilized plasmid downstream from an osomotically regulated ompC promoter. pGA2-CS4 directs production of CS4 fimbriae in both E. coli DH5α and Shigella flexneri 2a vaccine strain CVD 1204, as detected by Western blot analysis and bacterial agglutination with anti-CS4 immune sera. Electron-microscopic examination of Shigella expressing CS4 confirmed the presence of fimbriae on the bacterial surface. Guinea pigs immunized with CVD 1204(pGA2-CS4) showed serum and mucosal antibody responses to both the Shigella vector and the ETEC fimbria CS4. Among the seven most prevalent fimbrial antigens of human ETEC, CS4 is the last to be cloned and sequenced. These findings pave the way for CS4 to be included in multivalent ETEC vaccines, including an attenuated Shigella live-vector-based ETEC vaccine.

scholarly journals Construction and Characterization of Bivalent Shigella flexneri 2a Vaccine Strains SC608(pCFAI) and SC608(pCFAI/LTB) That Express Antigens from Enterotoxigenic Escherichia coli

2005 ◽  
Vol 73 (1) ◽  
pp. 258-267 ◽  
Author(s):  
Ryan T. Ranallo ◽  
C. Piyumi Fonseka ◽  
Fred Cassels ◽  
Jay Srinivasan ◽  
Malabi M. Venkatesan
Keyword(s):  
Escherichia Coli ◽  
Vaccine Strain ◽  
Shigella Flexneri ◽  
Immunoblot Analysis ◽  
Enterotoxigenic Escherichia Coli ◽  
Enzyme Linked Immunosorbent Assay ◽  
Live Attenuated Vaccine ◽  
Fimbrial Subunit ◽  
Semialdehyde Dehydrogenase ◽  
Structural Subunit

ABSTRACT An invasive strain of Shigella flexneri 2a (SC608) has been developed as a vector for the expression and delivery of heterologous antigens. SC608 is an aspartate semialdehyde dehydrogenase (asd) derivative of SC602 (icsA iuc), a well-characterized live attenuated vaccine strain which has undergone several clinical trials in human volunteers. When administered orally at a single 104 (CFU) dose, SC602 is both immunogenic and efficacious against shigellosis. Using asd-based plasmid vectors, we designed SC608 to express the enterotoxigenic Escherichia coli (ETEC) fimbrial subunit CfaB (CFA/I structural subunit) alone or in combination with the E. coli B subunit of heat-labile enterotoxin (LTB). The expression of each heterologous protein in SC608 was verified by immunoblot analysis. Each strain was comparable to the parent strain, SC602, in a HeLa cell invasion assay. After intranasal immunizations of guinea pigs, serum and mucosal immune responses were detected against both Shigella lipopolysaccharide and heterologous ETEC antigens by enzyme-linked immunosorbent assay and ELISPOT analysis. All immunized animals were subsequently protected against a challenge with wild-type S. flexneri 2a in a keratoconjunctivitis Sereny test. Serum antibodies generated against LTB and CfaB demonstrated antitoxin and agglutination activities, respectively. These results suggest that CfaB and LTB expressed in SC608 retain important conformational epitopes that are required for the generation of antibodies that have functional activities. These initial experiments demonstrate that a fully invasive Shigella vaccine strain can be engineered to deliver antigens from other diarrheal pathogens.

scholarly journals Attenuated Shigella flexneri 2a Vaccine Strain CVD 1204 Expressing Colonization Factor Antigen I and Mutant Heat-Labile Enterotoxin of Enterotoxigenic Escherichia coli

2000 ◽  
Vol 68 (9) ◽  
pp. 4884-4892 ◽  
Author(s):  
Hilary Koprowski ◽  
Myron M. Levine ◽  
Richard J. Anderson ◽  
Genevieve Losonsky ◽  
Mariagrazia Pizza ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Vaccine Strain ◽  
Guinea Pigs ◽  
Oral Vaccine ◽  
Shigella Flexneri ◽  
Surface Expression ◽  
Enterotoxigenic Escherichia Coli ◽  
Secretory Iga ◽  
Colonization Factor ◽  
Heat Labile

ABSTRACT A multivalent live oral vaccine against both Shigellaspp. and enterotoxigenic Escherichia coli (ETEC) is being developed based on the hypothesis that protection can be achieved if attenuated shigellae express ETEC fimbrial colonization factors and genetically detoxified heat-labile toxin from a human ETEC isolate (LTh). Two detoxified derivatives of LTh, LThK63 and LThR72, were engineered by substitution—serine to lysine at residue 63, or lysine to arginine at residue 72. The genes encoding these two derivatives were cloned separately on expression plasmids downstream from the CFA/I operon. Following electroporation into S. flexneri 2a vaccine strain CVD 1204, coexpression of CFA/I and LThK63 or LThR72 was demonstrated by Western blot analysis, GM1 binding assays, and agglutination with anti-CFA/I antiserum. Hemagglutination and electron microscopy confirmed surface expression of CFA/I. Guinea pigs immunized intranasally on days 0 and 15 with CVD 1204 expressing CFA/I and LThK63 or LThR72 exhibited high titers of both serum immunoglobulin G (IgG) and mucosal secretory IgA anti-CFA/I; 40% of the animals produced antibodies directed against LTh. All immunized guinea pigs also produced mucosal IgA (in tears) and serum IgG anti-S. flexneri 2a O antibodies. Furthermore, all immunized animals were protected from challenge with wild-type S. flexneri 2a. This prototype Shigella-ETEC hybrid vaccine demonstrates the feasibility of expressing multiple ETEC antigens on a single plasmid in an attenuated Shigella vaccine strain and engendering immune responses against both the heterologous antigens and vector strain.

scholarly journals EatA, an Immunogenic Protective Antigen of Enterotoxigenic Escherichia coli, Degrades Intestinal Mucin

2013 ◽  
Vol 82 (2) ◽  
pp. 500-508 ◽  
Author(s):  
Pardeep Kumar ◽  
Qingwei Luo ◽  
Tim J. Vickers ◽  
Alaullah Sheikh ◽  
Warren G. Lewis ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Protective Antigen ◽  
Shigella Flexneri ◽  
Enterotoxigenic Escherichia Coli ◽  
Effective Vaccine ◽  
Major Protein ◽  
Passenger Domain ◽  
Content Type ◽  
Intestinal Mucin

ABSTRACTEnterotoxigenicEscherichia coli(ETEC) is a major cause of morbidity and mortality due to infectious diarrhea in developing countries for which there is presently no effective vaccine. A central challenge in ETEC vaccinology has been the identification of conserved surface antigens to formulate a broadly protective vaccine. Here, we demonstrate that EatA, an immunogenic secreted serine protease of ETEC, contributes to virulence by degrading MUC2, the major protein present in the small intestinal mucous layer, and that removal of this barrierin vitroaccelerates toxin access to the enterocyte surface. In addition, we demonstrate that vaccination with the recombinant secreted passenger domain of EatA (rEatAp) elicits high titers of antibody and is protective against intestinal infection with ETEC. These findings may have significant implications for development of both subunit and live-attenuated vaccines against ETEC and other enteric pathogens, includingShigella flexneri, that express similar proteins.

scholarly journals Deletion of FaeG alleviated Enterotoxigenic Escherichia coli F4ac-induced apoptosis in the intestine

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pengpeng Xia ◽  
Yunping Wu ◽  
Siqi Lian ◽  
Guomei Quan ◽  
Yiting Wang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Clinical Symptoms ◽  
Mucosal Damage ◽  
Enterotoxigenic Escherichia Coli ◽  
Intestinal Epithelial ◽  
Antibody Microarray ◽  
E Coli ◽  
Fimbrial Subunit ◽  
Induced Apoptosis ◽  
Weaning Piglets

AbstractEnterotoxigenic Escherichia coli (ETEC) F4ac is a major constraint to the development of the pig industry, which is causing newborn and post-weaning piglets diarrhea. Previous studies proved that FaeG is the major fimbrial subunit of F4ac E. coli and efficient for bacterial adherence and receptor recognition. Here we show that the faeG deletion attenuates both the clinical symptoms of F4ac infection and the F4ac-induced intestinal mucosal damage in piglets. Antibody microarray analysis and the detection of mRNA expression using porcine neonatal jejunal IPEC-J2 cells also determined that the absence of FaeG subunit alleviated the F4ac promoted apoptosis in the intestinal epithelial cells. Thus, targeted depletion of FaeG is still beneficial for the prevention or treatment of F4ac infection.

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