Isolation of K88 Antigen Variants (ab, ac, ad) from Porcine Enterotoxigenic <i>Escherichia coli</i> Belonging to Different Serotypes

González, Enrique A.; Vázquez, Froilán; Garabal, J.I.; Blanco, Jorge

doi:10.1111/j.1348-0421.1995.tb03296.x

Cited by 16 publications

(9 citation statements)

References 31 publications

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“…The predominantly identified FaeGac adhesin, which is associated with acute diarrhea in piglets (19), was used to immunize a llama. Using phage-display technology, the VHHs from the llama immune library were panned against the antigens FaeGac and FaeGad for isolating VHHs specific for conserved epitopes of FaeG variants.…”

Section: Anti-f4mentioning

confidence: 99%

Orally fed seeds producing designer IgAs protect weaned piglets against enterotoxigenicEscherichia coliinfection

Virdi

Coddens

Buck

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

121

132

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Oral feed-based passive immunization can be a promising strategy to prolong maternal lactogenic immunity against postweaning infections. Enterotoxigenic Escherichia coli (ETEC)-caused postweaning diarrhea in piglets is one such infection that may be prevented by oral passive immunization and might avert recurrent economic losses to the pig farming industry. As a proof of principle, we designed anti-ETEC antibodies by fusing variable domains of llama heavy chain-only antibodies (VHHs) against ETEC to the Fc part of a porcine immunoglobulin (IgG or IgA) and expressed them in Arabidopsis thaliana seeds. In this way, four VHH-IgG and four VHH-IgA antibodies were produced to levels of about 3% and 0.2% of seed weight, respectively. Cotransformation of VHH-IgA with the porcine joining chain and secretory component led to the production of light-chain devoid, assembled multivalent dimeric, and secretory IgA-like antibodies. In vitro analysis of all of the antibody-producing seed extracts showed inhibition of bacterial binding to porcine gut villous enterocytes. However, in the piglet feed-challenge experiment, only the piglets receiving feed containing the VHH-IgA-based antibodies (dose 20 mg/d per pig) were protected. Piglets receiving the VHH-IgA-based antibodies in the feed showed a progressive decline in shedding of bacteria, significantly lower immune responses corroborating reduced exposure to the ETEC pathogen, and a significantly higher weight gain compared with the piglets receiving VHH-IgG producing (dose 80 mg/d per pig) or wild-type seeds. These results stress the importance of the antibody format in oral passive immunization and encourage future expression of these antibodies in crop seeds. molecular farming | mucosal immunity | nanobody | enteric infections | antibiotic replacement

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Section: Anti-f4mentioning

confidence: 99%

Orally fed seeds producing designer IgAs protect weaned piglets against enterotoxigenicEscherichia coliinfection

Virdi

Coddens

Buck

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

121

132

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“…These three K88 fimbrial variants differ in hemagglutination and porcine enterocyte binding activities, which suggests that they have binding specificities to different host receptors (2,5). K88ac fimbrial ETEC strains are by far most commonly associated with clinical diarrheal disease in young pigs (18,48,49) and are the only K88 ϩ ETEC variant associated with porcine diarrheal disease in the United States (48).…”

mentioning

confidence: 99%

Characterization of the Binding Specificity of K88ac and K88ad Fimbriae of Enterotoxigenic Escherichia coli by Constructing K88ac/K88ad Chimeric FaeG Major Subunits

2009

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Enterotoxigenic Escherichia coli (ETEC) strains expressing K88 (F4) fimbriae are the major cause of diarrhea in young pigs. Three antigenic variants of K88 fimbriae (K88ab, K88ac, and K88ad) have been identified among porcine ETEC strains. Each K88 fimbrial variant shows a unique pattern in binding to different receptors on porcine enterocytes. Such variant specificity in fimbrial binding is believed to be controlled by the major subunit (FaeG) of the K88 fimbriae, because the genes coding for the only other fimbrial subunit are identical among the three variants. Uniqueness in binding to host receptors may be responsible for differences in the virulence levels of porcine diarrhea disease caused by K88 ETEC strains. To better understand the relationships between the structure of FaeG proteins and fimbrial binding function, and perhaps virulence in disease, we constructed and expressed various K88ac/K88ad faeG gene chimeras and characterized the binding activity of each K88 chimeric fimbria. After verifying biosynthesis of the chimeric fimbriae, we examined their binding specificities in bacterial adherence assays by using porcine brush border vesicles that are specific to either the K88ac or K88ad fimbria. Results showed that each fimbria switched binding specificity to that of the reciprocal type when a peptide comprising amino acids 125 to 163 was exchanged with that of its counterpart. Substitutions of a single amino acid within this region negatively affected the binding capacity of each fimbria. These data indicate that the peptide including amino acids 125 to 163 of the FaeG subunit is essential for K88 variant-specific binding.Enterotoxigenic Escherichia coli (ETEC) strains are a major cause of diarrheal disease in humans and farming animals (37,40,41,47,50). The key virulence factors of ETEC in diarrhea include (i) bacterial adhesins or colonization factor antigens that mediate bacterial attachment to host enterocytes and initiate E. coli colonization and (ii) enterotoxins, which disrupt fluid homeostasis in the host small intestines and cause fluid hyper-secretion that results in diarrhea. For pigs, ETEC strains expressing K88 fimbriae are responsible for much of the neonatal, and a majority of the postweaning, diarrheal infections (11,14,24,34,49,51).

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“…Three serological variants of K88 exist in nature: K88ab, K88ac, and K88ad (14,22,32,37). However, K88ac is by far the most common variant associated with diarrheal disease in pigs (18,39). Each antigenic variant of K88 exhibits uniqueness in its hemagglutinating properties with respect to erythrocytes from various species (2,4).…”

mentioning

confidence: 99%

Inhibition of Adhesion ofEscherichia coliK88ac Fimbria to Its Receptor, Intestinal Mucin-Type Glycoproteins, by a Monoclonal Antibody Directed against a Variable Domain of the Fimbria

et al. 2000

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Strains of enterotoxigenic Escherichia coli that express K88 fimbriae are among the most common causes of diarrhea in young pigs. Adhesion of bacteria to receptors on intestinal epithelial cells, mediated by K88 fimbriae, is the initial step in the establishment of infection. Three antigenic variants of K88 fimbriae exist in nature: K88ab, K88ac, and K88ad. K88ac is the most prevalent and may be the only variant of significance in swine disease. Each K88 fimbrial variant is composed of multiple antigenic determinants. Some of these determinants are shared among the three variants and may be referred to as conserved epitopes, whereas others are unique to a specific variant and may be referred to as variable epitopes. In this study, monoclonal antibodies (MAbs) specific to either variable or conserved epitopes of K88ac fimbriae were produced. The specificity of each MAb was tested by enzyme-linked immunosorbent and immunoblot assays. Fab fragments were prepared from these MAbs and were tested for their ability to block the binding of K88-positive bacteria and purified fimbriae to porcine enterocyte brush border vesicles and purified K88 receptors, respectively. The purified receptors were intestinal mucin-type sialoglycoproteins (

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Isolation of K88 Antigen Variants (ab, ac, ad) from Porcine Enterotoxigenic Escherichia coli Belonging to Different Serotypes

Cited by 16 publications

References 31 publications

Orally fed seeds producing designer IgAs protect weaned piglets against enterotoxigenicEscherichia coliinfection

Orally fed seeds producing designer IgAs protect weaned piglets against enterotoxigenicEscherichia coliinfection

Characterization of the Binding Specificity of K88ac and K88ad Fimbriae of Enterotoxigenic Escherichia coli by Constructing K88ac/K88ad Chimeric FaeG Major Subunits

Inhibition of Adhesion ofEscherichia coliK88ac Fimbria to Its Receptor, Intestinal Mucin-Type Glycoproteins, by a Monoclonal Antibody Directed against a Variable Domain of the Fimbria

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