title: Enterotoxicity and immunological properties of two mutant forms of Escherichia coli STIp with lysine or arginine substituted for the asparagine residue at position 11.
abstract: Two variants of Escherichia coli heat-stable enterotoxin Ip, in which the amino acid residue at position 11 was substituted with lysine or arginine, were purified to near homogeneity from the culture supernatants of toxin-producing mutant strains. Neither the purified heat-stable enterotoxin Ip(Lys-11) nor the purified heat-stable enterotoxin Ip(Arg-11) showed a positive response in the suckling mouse assay or in the mouse intestinal loop assay. Furthermore, live bacteria producing these mutant heat-stable Ip enterotoxins did not cause fluid accumulation in mouse intestinal loops, in contrast to bacteria producing native heat-stable enterotoxin Ip. Nevertheless, antisera raised against both heat-stable enterotoxin Ip(Lys-11) and heat-stable enterotoxin Ip(Arg-11) neutralized the enterotoxic activity of native heat-stable enterotoxin Ip. These results demonstrate that heat-stable enterotoxin Ip(Lys-11) and heat-stable enterotoxin Ip(Arg-11) lose enterotoxicity but retain epitopes which are common to native heat-stable enterotoxin Ip.
authors.affiliation: Department of Biochemistry, Faculty of Pharmaceutical Sciences, Tokushima Buni University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Okamoto
authors.forename: J
authors.initials: J
authors.lastname: Yukitake
authors.forename: K
authors.initials: K
authors.lastname: Okamoto
authors.forename: A
authors.initials: A
authors.lastname: Miyama
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial; D001427:Bacterial Toxins / Q000235:genetics / Q000276:immunology / Q000633:toxicity*; D001428:Bacterial Vaccines / Q000302:isolation & purification; D004768:Enterotoxins / Q000235:genetics / Q000276:immunology / Q000633:toxicity*; D004926:Escherichia coli / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000517:prevention & control; D029968:Escherichia coli Proteins; D007422:Intestines / Q000187:drug effects; D051379:Mice; D016297:Mutagenesis, Site-Directed; D009500:Neutralization Tests
chemical_list: D000907:Antibodies, Bacterial; D001427:Bacterial Toxins; D001428:Bacterial Vaccines; D004768:Enterotoxins; D029968:Escherichia coli Proteins; C034151:heat stable toxin (E coli)