Cloning, nucleotide sequence, and hybridization studies of the type IIb heat-labile enterotoxin gene of Escherichia coli

Pickett, Carol L.; Twiddy, E M; Coker, Christopher; Holmes, Randall K.

doi:10.1128/jb.171.9.4945-4952.1989

Cited by 47 publications

(47 citation statements)

References 47 publications

(55 reference statements)

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“…The genes coding for LTIIa and LT-IIb are chromosome-located (Guth et al, 1986;Holmes et al, 1986;Pickett et al, 1986;Fukuta et al, 1988;Pickett et al, 1989).…”

Section: The Heat-labile Enterotoxinsmentioning

confidence: 99%

Escherichia coli virulence factors

Mainil

2013

Veterinary Immunology and Immunopathology

122

104

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a b s t r a c t Escherichia coli was described in 1885 by a German pediatrician, Theodor Escherich, in the faeces of a child suffering diarrhoea. In 1893, a Danish veterinarian postulated that the E. coli species comprises different strains, some being pathogens, others not. Today the E. coli species is subdivided into several pathogenic strains causing different intestinal, urinary tract or internal infections and pathologies, in animal species and in humans. Since this congress topic is the interaction between E. coli and the mucosal immune system, the purpose of this manuscript is to present different classes of adhesins (fimbrial adhesins, afimbrial adhesins and outer membrane proteins), the type 3 secretion system, and some toxins (oligopeptide, AB, and RTX pore-forming toxins) produced by E. coli, that can directly interact with the epithelial cells of the intestinal, respiratory and urinary tracts.

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“…The genes coding for LTIIa and LT-IIb are chromosome-located (Guth et al, 1986;Holmes et al, 1986;Pickett et al, 1986;Fukuta et al, 1988;Pickett et al, 1989).…”

Section: The Heat-labile Enterotoxinsmentioning

confidence: 99%

Escherichia coli virulence factors

Mainil

2013

Veterinary Immunology and Immunopathology

122

104

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“…While the B polypeptides of CT and LT-I exhibit over 80% homology to each other, both CT and LT-I have less than 14% amino acid sequence homology to the B subunits of either LT-IIa or LT-IIb (15,(28)(29)(30). The extensive diversity in amino acid sequences between type I and type II HLT not only results in antigenically distinct groups but also imparts different ganglioside binding specificity to the respective B subunits.…”

mentioning

confidence: 99%

Comparative Analysis of the Mucosal Adjuvanticity of the Type II Heat-Labile Enterotoxins LT-IIa and LT-IIb

et al. 2000

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The heat-labile enterotoxins (HLT) of Vibrio cholerae and Escherichia coli constitute a family of bacterial toxins that are related in structure and function (10,11,16,35). Both are oligomeric protein toxins composed of one A polypeptide and five B polypeptides in which the quaternary structure is maintained by noncovalent bonds between the A polypeptide and a pentameric ring of B subunits (7,13,32). The biological effects of the enterotoxins are determined by the binding specificity of the fully assembled B subunits and the enzymatic activity of the A subunit. The pentameric ring formed by the B subunits mediates binding to the sugar residues of gangliosides present on the surface of various eukaryotic cells (3,18).Two serogroups of HLT have been distinguished on the basis of distinct immunoreactivity (15, 28). Serogroup I consists of cholera toxin (CT) and the E. coli HLT LT-I, which includes two antigenic variants isolated from humans and pigs, designated respectively (19,28). Serogroup II enterotoxins include E. coli type II HLT initially designated LT-like toxins and later called LT-II enterotoxins (9). Based on immunoreactivity and amino acid sequence homology, two antigenic variants of LT-II, designated LT-IIa and LT-IIb, have been isolated (9)(10)(11)17). Although serogroup I and serogroup II enterotoxins induce similar morphological effects on Y1 adrenal cells and activate adenylate cyclase in cell cultures, both LT-IIa and LT-IIb appear to be more potent than either CT or LT-I in Y1 adrenal cell assays; however, neither LT-IIa nor LT-IIb induces the typical fluid accumulation in ligated ileal loops observed with CT and LT-I (16). In human T84 intestinal cells, only CT elicited a cyclic AMP-dependent chloride response that is responsible for the massive effusion of water into the lumen of the gut (39).Comparison of the predicted amino acid sequences of type I and type II enterotoxins reveals a large degree of variability. While the B polypeptides of CT and LT-I exhibit over 80% homology to each other, both CT and LT-I have less than 14% amino acid sequence homology to the B subunits of either LT-IIa or [28][29][30]. The extensive diversity in amino acid sequences between type I and type II HLT not only results in antigenically distinct groups but also imparts different ganglioside binding specificity to the respective B subunits. Specifically, the high-affinity receptor for CT and LT

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“…Of the two, LT-I is most commonly associated with animal and human ETEC strains. A homology of 55% has been reported between LT and cholera toxin (CT) suggesting they are conserved and possess similar modes of actions (Pickett et al, 1989).…”

Section: Lt Toxinmentioning

confidence: 99%