Genetically engineered enteropathogenic Escherichia coli strain elicits a specific immune response and protects against a virulent challenge.
Enteropathogenic Escherichia coli (EPEC), a major cause of severe disease with diarrhea in infants, is also involved in weaned rabbit colibacillosis. EPEC O103 is frequent in rabbit-fattening units of Western Europe. It causes high mortality and growth retardation, leading to substantial economic losses. We report here the construction by allelic exchange of an EPEC O103 strain mutated in espB and tir, two essential virulence genes. Upon live oral administration to weaned rabbits, the E22DeltaTir/EspB mutant strain efficiently colonized the intestinal tract without any adverse consequences. The rabbits were challenged with the highly pathogenic parental strain E22. The mutant provided complete protection to rabbits and total resistance to intestinal colonization by E22. In addition, E22DeltaTir/EspB strain induced a specific humoral response against the bacterial adhesin AF/R2. These Abs prevent bacterial attachment to epithelial cells in vitro. These results open the way for the development of an efficient vaccine strategy against rabbit EPEC infections.
Boullier
Séverine
S
UMR 1225, Institut National de la Recherche Agronomique, Ecole Nationale Vétérinaire de Toulouse, 31076 Toulouse cedex 3, France. s.boullier@envt.fr
Nougayrède
Jean-Philippe
JP
Marchès
Olivier
O
Tasca
Christian
C
Boury
Michèle
M
Oswald
Eric
E
De Rycke
Jean
J
Milon
Alain
A
D018830:Adhesins, Escherichia coli / Q000276:immunology; D000284:Administration, Oral; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology; D001422:Bacterial Adhesion / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics; D001835:Body Weight; D003967:Diarrhea / Q000276:immunology / Q000382:microbiology; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000276:immunology* / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000276:immunology* / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics; D017353:Gene Deletion; D006367:HeLa Cells; D006801:Humans; D007422:Intestines / Q000382:microbiology; D016254:Mutagenesis, Insertional; D011817:Rabbits; D011956:Receptors, Cell Surface / Q000235:genetics; D014774:Virulence / Q000235:genetics
D018830:Adhesins, Escherichia coli; D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; C087863:EaeB protein, E coli; D029968:Escherichia coli Proteins; D011956:Receptors, Cell Surface; C109287:Tir protein, E coli; C103954:afr2 protein, E coli