Mutants of Escherichia coli heat-labile toxin lacking ADP-ribosyltransferase activity act as nontoxic, mucosal adjuvants.
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.
Douce
G
G
Department of Biochemistry, Imperial College of Science, Technology and Medicine, London, United Kingdom.
Turcotte
C
C
Cropley
I
I
Roberts
M
M
Pizza
M
M
Domenghini
M
M
Rappuoli
R
R
Dougan
G
G
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
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