Vaccines for preventing enterotoxigenic Escherichia coli infections in farm animals

Moon, Harley W.; Bunn, Thomas O.

doi:10.1016/0264-410x(93)90020-x

Cited by 166 publications

(66 citation statements)

References 55 publications

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“…The repetitive nature of the helically arranged subunits results in the display of the same epitopes 10 2 to 10 3 times on each fimbrial thread, or 10 5 to 10 6 times on each bacterial surface, rendering fimbriae major immunogens of fimbriated killed or live bacterial vaccines. A vaccine based on wild-type fimbriae has been successfully used, for example to prevent enterotoxigenic Escherichia coli diarrhoeal infections in farm animals (Moon & Bunn, 1993). The results obtained confirmed the high immunogenicity of fimbriae in live vaccines and purified proteins.…”

Section: Introductionmentioning

confidence: 61%

DAF- and collagen-binding properties of chimeric Dr fimbriae

et al. 2007

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Display of heterologous proteins on the surface of micro-organisms has become an increasingly used strategy for a range of applications in microbiology, biotechnology and vaccinology. In this study, the potential of the major structural protein DraE of Escherichia coli Dr fimbriae as a display system for heterologous sequences was tested. One copy of a heterologous sequence mimicking a small P k epitope of simian virus 5 was inserted into the draE gene, replacing the N-terminal region of the surface-exposed domain 2 as previously done with the glycoprotein D of herpes simplex virus type 1. The exposure of chimeric proteins on the bacterial surface was detected by immunofluorescence microscopy. Insertion of the heterogenic peptides had no detectable effect on the Ig-barrel structure of the DraE fimbrial subunits, as confirmed by FTIR spectroscopy. Additionally, the affinity of the chimeric fimbriae for DAF and type IV collagen was similar to that of the wild-type Dr fimbriae.

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Section: Introductionmentioning

confidence: 61%

DAF- and collagen-binding properties of chimeric Dr fimbriae

et al. 2007

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“…In swine production, diarrheal diseases precipitate major economic losses through high mortality rates, poor feed intake and poor growth (Wegmann 1990;Moon and Burn 1993). Comparatively little progress has been made in the development of vaccines to protect pigs against post-weaning diarrhea and edema disease.…”

Section: Vaccinationmentioning

confidence: 99%

Subtherapeutic use of antibiotics in pork production: Risks and alternatives

Adjiri-Awere¹,

Lunen²

2005

Can. J. Anim. Sci.

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The purpose of this review is to discuss the issue of subtherapeutic use of antibiotics in pork production and possible alternatives. Specifically, the review describes the potential problem of antibiotic resistance and reviews disease prevention and immune potentiation strategies as alternatives to subtherapeutic antibiotics. In recent years, the use of in-feed subtherapeutic antibiotics by the pork industry for growth promotion and disease prophylaxis has come under increased scrutiny. The potential risk of bacteria acquiring resistance to specific antibiotics and the detrimental effects that this may have on human health has resulted in the banning of certain antibiotics in some European countries. Despite the current interest in the reduction or elimination of subtherapeutic antibiotic use in livestock production, there may be a risk that such a reduction or elimination would have negative effects on animal welfare, nutrient utilization, manure production and economic sustainability. A number of alternatives to subtherapeutic antibiotics appear promising; however, more research is required before they can be considered viable commercial products. Consequently, a systems approach involving nutrition, bacteriology, immunology, pathology and herd management is needed to find a cost-effective and practical way to maximize the efficient production of high-quality pork without the use of subtherapeutic antibiotics. Key words: Pig, pork production, subtherapeutic antibiotics, alternatives

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“…The hybrid operon was constructed using an intermediate vector pRCK18, a derivative of pK18 (38) in which the polylinker sequence had been replaced by one with sites for BamHIXbaI-SpeI-ClaI-KpnI-NdeI-EcoRV-ApaI-PstI. 3 The EcoRV-KpnI fragment from pRC7 was inserted into pRCK18, followed by insertion of the KpnI-SpeI fragment from pRC2. The resultant plasmid was cleaved with EcoRV and SpeI and the hybrid operon cloned into the correspond- 2 The ApaI site is immediately adjacent to the EcoRV site shown in Fig.…”

Section: Construction Of Mutant and Hybrid Toxin Operonsmentioning

confidence: 99%

“…1. 3 Difficulties were encountered in the construction of the hybrid operons, possibly due to the toxicity of gene products encoded by fragments of the toxin genes; and necessitated the design and use of an intermediate vector.…”

Section: Construction Of Mutant and Hybrid Toxin Operonsmentioning

confidence: 99%

“…1). A structurally and functionally similar toxin, heat-labile enterotoxin (Etx), is produced by certain strains of enterotoxigenic Escherichia coli that are responsible for causing the generally milder "traveler's" diarrhea of humans and scouring in farm animals (2,3). Both Ctx and Etx are hetero-oligomeric proteins comprised of a single A-subunit (M r 28,000) and five B-subunits (M r 12,000 each) (4 -6).…”

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confidence: 99%

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Structural Basis for the Differential Toxicity of Cholera Toxin and Escherichia coli Heat-labile Enterotoxin

Rodighiero

Aman

Kenny

et al. 1999

Journal of Biological Chemistry

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Cholera toxin (Ctx) and E. coli heat-labile enterotoxin (Etx) are structurally and functionally similar AB 5 toxins with over 80% sequence identity. When their action in polarized human epithelial (T84) cells was monitored by measuring toxin-induced Cl ؊ ion secretion, Ctx was found to be the more potent of the two toxins. Here, we examine the structural basis for this difference in toxicity by engineering a set of mutant and hybrid toxins and testing their activity in T84 cells. This revealed that the differential toxicity of Ctx and Etx was (i) not due to differences in the A-subunit's C-terminal KDEL targeting motif (which is RDEL in Etx), as a KDEL to RDEL substitution had no effect on cholera toxin activity; (ii) not attributable to the enzymatically active A1-fragment, as hybrid toxins in which the A1-fragment in Ctx was substituted for that of Etx (and vice versa) did not alter relative toxicity; and (iii) not due to the B-subunit, as the replacement of the B-subunit in Ctx for that of Etx caused no alteration in toxicity, thus excluding the possibility that the broader receptor specificity of EtxB is responsible for reduced activity. Remarkably, the difference in toxicity could be mapped to a 10-amino acid segment of the A2-fragment that penetrates the central pore of the B-subunit pentamer. A comparison of the in vitro stability of two hybrid toxins, differing only in this 10-amino acid segment, revealed that the Ctx A2-segment conferred a greater stability to the interaction between the A-and B-subunits than the corresponding segment from Etx A2. This suggests that the reason for the relative potency of Ctx compared with Etx stems from the increased ability of the A2-fragment of Ctx to maintain holotoxin stability during uptake and transport into intestinal epithelia.The severe, and at times fatal, diarrheal disease caused by Vibrio cholerae is due to the potent action of cholera toxin (Ctx) 1 (for a review, see Ref. 1). A structurally and functionally similar toxin, heat-labile enterotoxin (Etx), is produced by certain strains of enterotoxigenic Escherichia coli that are responsible for causing the generally milder "traveler's" diarrhea of humans and scouring in farm animals (2, 3). Both Ctx and Etx are hetero-oligomeric proteins comprised of a single A-subunit (M r 28,000) and five B-subunits (M r 12,000 each) (4 -6). The A-subunit contains two distinct structural domains linked by a disulfide bridge: an A1-fragment (residues 1-192) that displays ADP-ribosyl transferase activity and an A2-fragment (residues 193-240) that mediates interaction with the B-subunit pentamer (4, 6). The B-subunits of Ctx and Etx (CtxB and EtxB, respectively) bind to cell surface receptors, principally G M1 -ganglioside, found ubiquitously on the plasma membranes of eukaryotic cells (7). Although Ctx and Etx exhibit a remarkable degree of structural homology, with 81.6% sequence identity between CtxA and EtxA and 82.5% sequence identity between CtxB and EtxB (8 -10), there are a number of subtle physicochemical and function...

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Vaccines for preventing enterotoxigenic Escherichia coli infections in farm animals

Cited by 166 publications

References 55 publications

DAF- and collagen-binding properties of chimeric Dr fimbriae

DAF- and collagen-binding properties of chimeric Dr fimbriae

Subtherapeutic use of antibiotics in pork production: Risks and alternatives

Structural Basis for the Differential Toxicity of Cholera Toxin and Escherichia coli Heat-labile Enterotoxin

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