Vaccination of calves with EspA, a key colonisation factor of Escherichia coli O157:H7, induces antigen-specific humoral responses but does not confer protection against intestinal colonisation

• Published in: Veterinary microbiology Vol. 123; no. 1; pp. 254 - 261
• Main Authors: Dziva, Francis, Vlisidou, Isabella, Crepin, Valérie F., Wallis, Timothy S., Frankel, Gad, Stevens, Mark P.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 20-07-2007; Elsevier Science
• Subjects: Animals; Antibodies, Bacterial - immunology; Antigens, Bacterial - immunology; Applied microbiology; bacterial antigens; bacterial colonization; Bacteriology; Biological and medical sciences; calves; Carrier State; Cattle; cattle diseases; Cattle Diseases - immunology; Cattle Diseases - prevention & control; chromosome elimination; Colonisation; Drug Administration Routes; enterocytes; Escherichia coli; Escherichia coli O157 - immunology; Escherichia coli O157:H7; Escherichia coli Proteins - immunology; Escherichia coli Vaccines - administration & dosage; Escherichia coli Vaccines - immunology; EspA; Fundamental and applied biological sciences. Psychology; humoral immunity; intestinal microorganisms; Intestines - microbiology; Male; Microbiology; Miscellaneous; mutants; Mutation; protective effect; Ruminantia; Time Factors; vaccination; Vaccine; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies (general aspects); Vaccine; Cattle; Colonisation; Escherichia coli; EspA; Bovine; Microbiology; Digestive system; Vaccination; Gut; Antigen; Vertebrata; Mammalia; Bacteria; Artiodactyla; Veterinary; Ungulata; Humoral immunity; Enterobacteriaceae
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/j.vetmic.2007.02.016

Enterohaemorrhagic
Escherichia coli (EHEC) infections in humans are frequently associated with direct or indirect contact with ruminant faeces and may result in haemorrhagic colitis and severe renal and neurological sequelae. Broadly cross-protective vaccines for control of EHEC do not yet exist and the molecular mechanisms that influence bacterial persistence in the intestines of ruminants are incompletely understood. We sought to determine the role in colonisation and protective efficacy of EspA, which forms a filamentous extension of the locus of enterocyte effacement-encoded type III secretion system that injects EHEC proteins into enterocytes. A non-polar deletion of
espA severely impaired the ability of
E. coli O157:H7 to colonise the intestines of calves. Vaccination of calves with highly purified recombinant EspA induced high-titre antigen-specific IgG1 (also reactive to native EspA) and salivary IgA responses, however these responses did not protect calves against intestinal colonisation by
E. coli O157:H7 upon experimental infection.