title: Immunogenicity and protective efficacy of a single-dose live non-pathogenic Escherichia coli oral vaccine against F4-positive enterotoxigenic Escherichia coli challenge in pigs.
abstract: Enterotoxigenic Escherichia coli strains expressing F4 (K88) fimbriae (F4-ETEC) are one of the most important causes of post-weaning diarrhea (PWD) in pigs. F4, a major antigen, plays an important role in the early steps of the infection. Herein, the efficacy of a live oral vaccine consisting of a non-pathogenic E. coli strain expressing F4 for protection of pigs against PWD was evaluated. Three blinded, placebo-controlled, block design, parallel-group confirmatory experiments were conducted, using an F4-ETEC PWD challenge model, each with a different vaccination-challenge interval (3, 7, and 21days). The pigs were vaccinated via the drinking water with a single dose of the Coliprotec® F4 vaccine one day post-weaning. Efficacy was assessed by evaluating diarrhea, clinical observations, intestinal fluid accumulation, weight gain, intestinal colonization and fecal shedding of F4-ETEC. The immune response was evaluated by measuring serum and intestinal F4-specific antibodies. The administration of the vaccine resulted in a significant reduction of the incidence of moderate to severe diarrhea, ileal colonization by F4-ETEC, and fecal shedding of F4-ETEC after the heterologous challenge at 7 and 21days post-vaccination. The 7-day onset of protection was associated with an increase of serum anti-F4 IgM whereas the 21-day duration of protection was associated with an increase of both serum anti-F4 IgM and IgA. Significant correlations between levels of serum and intestinal secretory anti-F4 antibodies were detected. Maternally derived F4-specific serum antibodies did not interfere with the vaccine efficacy. The evaluation of protection following a challenge three days after vaccination showed a reduction of the severity and the duration of diarrhea and of fecal shedding of F4-ETEC. The 7-day onset and the 21-day duration of protection induced by Coliprotec® F4 vaccine administered once in drinking water to pigs of at least 18days of age were confirmed by protection against F4-ETEC and induction of F4-specific protective immunity.
authors.affiliation: OIE Reference Laboratory for Escherichia coli (EcL), Faculty of Veterinary Medicine, Université de Montréal, 3200 Sicotte Street, Saint-Hyacinthe, Québec J2S 2M2, Canada.
authors.forename: John Morris
authors.initials: JM
authors.lastname: Fairbrother
authors.affiliation: Prevtec Microbia Inc., 3395 Casavant Blvd. West, Saint-Hyacinthe, Québec J2S 0B8, Canada. Electronic address: enadeau@prevtecmicrobia.com.
authors.forename: Éric
authors.initials: É
authors.lastname: Nadeau
authors.affiliation: Prevtec Microbia Inc., 3395 Casavant Blvd. West, Saint-Hyacinthe, Québec J2S 0B8, Canada.
authors.forename: Louise
authors.initials: L
authors.lastname: Bélanger
authors.affiliation: Prevtec Microbia Inc., 3395 Casavant Blvd. West, Saint-Hyacinthe, Québec J2S 0B8, Canada.
authors.forename: Cindy-Love
authors.initials: CL
authors.lastname: Tremblay
authors.affiliation: Prevtec Microbia Inc., 3395 Casavant Blvd. West, Saint-Hyacinthe, Québec J2S 0B8, Canada.
authors.forename: Danielle
authors.initials: D
authors.lastname: Tremblay
authors.affiliation: Prevtec Microbia Inc., 3395 Casavant Blvd. West, Saint-Hyacinthe, Québec J2S 0B8, Canada.
authors.forename: Mélanie
authors.initials: M
authors.lastname: Brunelle
authors.affiliation: KLIFOVET AG, Geyerspergerstr. 27, 80689 Munich, Germany.
authors.forename: Regina
authors.initials: R
authors.lastname: Wolf
authors.affiliation: KLIFOVET AG, Geyerspergerstr. 27, 80689 Munich, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Hellmann
authors.affiliation: Elanco Animal Health, Eli Lilly and Company Limited, Basingstoke, Hampshire, United Kingdom.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Hidalgo
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis / Q000097:blood; D000917:Antibody Formation; D057138:Bacterial Shedding; D003967:Diarrhea / Q000382:microbiology / Q000473:pathology / Q000517:prevention & control / Q000662:veterinary*; D054307:Enterotoxigenic Escherichia coli / Q000276:immunology*; D004927:Escherichia coli Infections / Q000382:microbiology / Q000473:pathology / Q000517:prevention & control / Q000662:veterinary*; D022361:Escherichia coli Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D007070:Immunoglobulin A / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007422:Intestines / Q000276:immunology; D010919:Placebos / Q000008:administration & dosage; D044967:Serum / Q000276:immunology; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology / Q000473:pathology / Q000517:prevention & control*; D016896:Treatment Outcome; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D022361:Escherichia coli Vaccines; D007070:Immunoglobulin A; D007075:Immunoglobulin M; D010919:Placebos; D014613:Vaccines, Attenuated
keywords: Enterotoxigenic Escherichia coli; F4 (K88) fimbriae; Immune response; Live vaccine; Pig; Post-weaning diarrhea