Cholera toxin improves the F4(K88)-specific immune response following oral immunization of pigs with recombinant FaeG.
Oral immunization of both humans and animals with non-replicating soluble antigens often results in the induction of oral tolerance. However, receptor-dependent uptake of orally administered soluble antigens can lead to the induction of an antigen-specific immune response. Indeed, oral immunization of pigs with recombinant FaeG (rFaeG), the adhesin of the F4(K88) fimbriae of enterotoxigenic Escherichia coli (ETEC), induces an F4-specific humoral and cellular immune response. This response is accompanied with a reduction in the excretion of F4(+)E. coli following challenge. To improve the immune response against F4, rFaeG was orally co-administered with the mucosal adjuvant cholera toxin (CT). Oral immunization of pigs with rFaeG and CT significantly improved the induction of an F4-specific humoral and cellular immune response and also significantly reduced the faecal F4(+)E. coli excretion following F4(+) ETEC challenge as compared to rFaeG-immunized pigs. Therefore, the present study demonstrates that CT can act in pigs as a mucosal adjuvant for antigens that bind to the intestinal epithelium by a CT-receptor-independent mechanism.
Verdonck
F
F
Laboratory of Veterinary Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium. frank.verdonch@ugent.ac.be
Snoeck
V
V
Goddeeris
B M
BM
Cox
E
E
D018830:Adhesins, Escherichia coli / Q000276:immunology*; D000284:Administration, Oral; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D000942:Antigens, Bacterial / Q000276:immunology*; D002772:Cholera Toxin / Q000494:pharmacology*; D029968:Escherichia coli Proteins / Q000276:immunology*; D022361:Escherichia coli Vaccines / Q000276:immunology*; D036781:Fimbriae Proteins / Q000276:immunology*; D007114:Immunization; D011994:Recombinant Proteins / Q000276:immunology; D013552:Swine; D014614:Vaccines, Synthetic / Q000276:immunology*
D018830:Adhesins, Escherichia coli; D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D029968:Escherichia coli Proteins; D022361:Escherichia coli Vaccines; C494388:FaeG protein, E coli; C026888:K88 antigen, E coli; D011994:Recombinant Proteins; D014614:Vaccines, Synthetic; D036781:Fimbriae Proteins; D002772:Cholera Toxin