title: Immune responses associated with homologous protection conferred by commercial vaccines for control of avian pathogenic Escherichia coli in turkeys.
abstract: Avian pathogenic Escherichia coli (APEC) infections are a serious impediment to sustainable poultry production worldwide. Licensed vaccines are available, but the immunological basis of protection is ill-defined and a need exists to extend cross-serotype efficacy. Here, we analysed innate and adaptive responses induced by commercial vaccines in turkeys. Both a live-attenuated APEC O78 ΔaroA vaccine (Poulvac® E. coli) and a formalin-inactivated APEC O78 bacterin conferred significant protection against homologous intra-airsac challenge in a model of acute colibacillosis. Analysis of expression levels of signature cytokine mRNAs indicated that both vaccines induced a predominantly Th2 response in the spleen. Both vaccines resulted in increased levels of serum O78-specific IgY detected by ELISA and significant splenocyte recall responses to soluble APEC antigens at post-vaccination and post-challenge periods. Supplementing a non-adjuvanted inactivated vaccine with Th2-biasing (Titermax® Gold or aluminium hydroxide) or Th1-biasing (CASAC or CpG motifs) adjuvants, suggested that Th2-biasing adjuvants may give more protection. However, all adjuvants tested augmented humoral responses and protection relative to controls. Our data highlight the importance of both cell-mediated and antibody responses in APEC vaccine-mediated protection toward the control of a key avian endemic disease.
authors.forename: Jean-Rémy
authors.initials: JR
authors.lastname: Sadeyen
authors.forename: Zhiguang
authors.initials: Z
authors.lastname: Wu
authors.forename: Holly
authors.initials: H
authors.lastname: Davies
authors.forename: Pauline M
authors.initials: PM
authors.lastname: van Diemen
authors.forename: Anita
authors.initials: A
authors.lastname: Milicic
authors.forename: Roberto M
authors.initials: RM
authors.lastname: La Ragione
authors.forename: Pete
authors.initials: P
authors.lastname: Kaiser
authors.forename: Mark P
authors.initials: MP
authors.lastname: Stevens
authors.affiliation: Avian Infectious Diseases Programme, The Pirbright Institute, Compton RG20 7NN, Berkshire, UK. francis.dziva@sta.uwi.edu.
authors.forename: Francis
authors.initials: F
authors.lastname: Dziva
mesh_terms: D056704:Adaptive Immunity; D000818:Animals; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D004926:Escherichia coli / Q000502:physiology; D004927:Escherichia coli Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D022361:Escherichia coli Vaccines / Q000276:immunology*; D005260:Female; D007113:Immunity, Innate; D011201:Poultry Diseases / Q000276:immunology* / Q000382:microbiology; D014422:Turkeys; D014613:Vaccines, Attenuated / Q000276:immunology; D015164:Vaccines, Inactivated / Q000276:immunology
chemical_list: D022361:Escherichia coli Vaccines; D014613:Vaccines, Attenuated; D015164:Vaccines, Inactivated