title: A systemic vaccine based on Escherichia coli O157:H7 bacterial ghosts (BGs) reduces the excretion of E. coli O157:H7 in calves.
abstract: Cattle are the main reservoir of enterohemorrhagic Escherichia coli O157:H7, a bacterium that, in humans, causes hemorrhagic colitis and hemolytic uremic syndrome (HUS), a life-threatening disease, especially in children and older people. Therefore, the development of vaccines preventing colonization of cattle by E. coli O157:H7 could be a main tool for an HUS control program. In the present study, we evaluated bacterial ghosts (BGs) of E. coli O157:H7 as an experimental vaccine against this pathogen. BGs are empty envelopes of Gram-negative bacteria, which retain the morphological surface make-up of their living counterparts and are produced by controlled expression of the cloned protein E, which causes loss of all the cytoplasm content. In this work, E. coli O157:H7 BGs were used for subcutaneous immunization of calves. The vaccinated animals elicited significant levels of BG-specific IgG but not IgA antibodies in serum. Low levels of IgA and IgG antibodies against BGs were detected in saliva from vaccinated animals. Following oral challenge with E. coli O157:H7, a significant reduction in both the duration and total bacterial shedding was observed in vaccinated calves compared to the nonimmunized group. We demonstrated that systemic vaccination with E. coli O157 BGs provides protection in a bovine experimental model. Further research is needed to reach a higher mucosal immune response leading to an optimal vaccine.
authors.affiliation: Instituto de Patobiología, Instituto Nacional de Tecnología Agropecuaria (INTA), Nicolás Repetto y De los Reseros, 1686 Hurlingham, Argentina.
authors.forename: D A
authors.initials: DA
authors.lastname: Vilte
authors.forename: M
authors.initials: M
authors.lastname: Larzábal
authors.forename: U B
authors.initials: UB
authors.lastname: Mayr
authors.forename: S
authors.initials: S
authors.lastname: Garbaccio
authors.forename: M
authors.initials: M
authors.lastname: Gammella
authors.forename: B C
authors.initials: BC
authors.lastname: Rabinovitz
authors.forename: F
authors.initials: F
authors.lastname: Delgado
authors.forename: V
authors.initials: V
authors.lastname: Meikle
authors.forename: R J C
authors.initials: RJ
authors.lastname: Cantet
authors.forename: P
authors.initials: P
authors.lastname: Lubitz
authors.forename: W
authors.initials: W
authors.lastname: Lubitz
authors.forename: A
authors.initials: A
authors.lastname: Cataldi
authors.forename: E C
authors.initials: EC
authors.lastname: Mercado
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D057138:Bacterial Shedding; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology / Q000382:microbiology* / Q000517:prevention & control*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D004927:Escherichia coli Infections / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D019453:Escherichia coli O157 / Q000276:immunology*; D022361:Escherichia coli Vaccines / Q000008:administration & dosage / Q000276:immunology*; D007114:Immunization / Q000379:methods / Q000662:veterinary; D008297:Male; D011897:Random Allocation
chemical_list: D000907:Antibodies, Bacterial; D022361:Escherichia coli Vaccines