title: Mutants of Escherichia coli heat-labile toxin lacking ADP-ribosyltransferase activity act as nontoxic, mucosal adjuvants.
abstract: A nontoxic mutant (LTK7) of the Escherichia coli heat-labile enterotoxin (LT) lacking ADP-ribosylating activity but retaining holotoxin formation was constructed. By using site-directed mutagenesis, the arginine at position 7 of the A subunit was replaced with lysine. This molecule, which was nontoxic in several assays, was able to bind to eukaryotic cells and acted as a mucosal adjuvant for co-administered proteins; BALB/c mice immunized intranasally with LTK7 and ovalbumin developed high levels of serum and local antibodies to ovalbumin and toxin. In addition, mice immunized intranasally with fragment C of tetanus toxin and LTK7 were protected against lethal challenge with tetanus toxin. Thus nontoxic mutants of heat-labile toxin can act as effective intranasal mucosal adjuvants.
authors.affiliation: Department of Biochemistry, Imperial College of Science, Technology and Medicine, London, United Kingdom.
authors.forename: G
authors.initials: G
authors.lastname: Douce
authors.forename: C
authors.initials: C
authors.lastname: Turcotte
authors.forename: I
authors.initials: I
authors.lastname: Cropley
authors.forename: M
authors.initials: M
authors.lastname: Roberts
authors.forename: M
authors.initials: M
authors.lastname: Pizza
authors.forename: M
authors.initials: M
authors.lastname: Domenghini
authors.forename: R
authors.initials: R
authors.lastname: Rappuoli
authors.forename: G
authors.initials: G
authors.lastname: Dougan
mesh_terms: D000276:Adjuvants, Immunologic; D000818:Animals; D001427:Bacterial Toxins / Q000737:chemistry / Q000276:immunology* / Q000633:toxicity; D004768:Enterotoxins / Q000737:chemistry / Q000276:immunology* / Q000633:toxicity; D004926:Escherichia coli; D029968:Escherichia coli Proteins; D005260:Female; D005753:Gastric Mucosa / Q000276:immunology*; D008168:Lung / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D016297:Mutagenesis, Site-Directed; D009297:Nasal Mucosa / Q000276:immunology*; D009666:Nose / Q000276:immunology; D010047:Ovalbumin / Q000276:immunology; D011065:Poly(ADP-ribose) Polymerases / Q000737:chemistry / Q000235:genetics / Q000633:toxicity; D013329:Structure-Activity Relationship
chemical_list: D000276:Adjuvants, Immunologic; D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D010047:Ovalbumin; C027538:heat-labile enterotoxin, E coli; D011065:Poly(ADP-ribose) Polymerases