title: Evaluation of a Salmonella Strain Lacking the Secondary Messenger C-di-GMP and RpoS as a Live Oral Vaccine.
abstract: Salmonellosis is one of the most important bacterial zoonotic diseases transmitted through the consumption of contaminated food, with chicken and pig related products being key reservoirs of infection. Although numerous studies on animal vaccination have been performed in order to reduce Salmonella prevalence, there is still a need for an ideal vaccine. Here, with the aim of constructing a novel live attenuated Salmonella vaccine candidate, we firstly analyzed the impact of the absence of cyclic-di-GMP (c-di-GMP) in Salmonella virulence. C-di-GMP is an intracellular second messenger that controls a wide range of bacterial processes, including biofilm formation and synthesis of virulence factors, and also modulates the host innate immune response. Our results showed that a Salmonella multiple mutant in the twelve genes encoding diguanylate cyclase proteins that, as a consequence, cannot synthesize c-di-GMP, presents a moderate attenuation in a systemic murine infection model. An additional mutation of the rpoS gene resulted in a synergic attenuating effect that led to a highly attenuated strain, referred to as ΔXIII, immunogenic enough to protect mice against a lethal oral challenge of a S. Typhimurium virulent strain. ΔXIII immunogenicity relied on activation of both antibody and cell mediated immune responses characterized by the production of opsonizing antibodies and the induction of significant levels of IFN-γ, TNF-α, IL-2, IL-17 and IL-10. ΔXIII was unable to form a biofilm and did not survive under desiccation conditions, indicating that it could be easily eliminated from the environment. Moreover, ΔXIII shows DIVA features that allow differentiation of infected and vaccinated animals. Altogether, these results show ΔXIII as a safe and effective live DIVA vaccine.
authors.affiliation: Laboratory of Microbial Biofilms, Instituto de Agrobiotecnología (Idab), Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Pamplona, Spain.|Recombina S. L. Mutilva, Navarra, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Latasa
authors.affiliation: Laboratory of Microbial Biofilms, Instituto de Agrobiotecnología (Idab), Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Pamplona, Spain.
authors.forename: Maite
authors.initials: M
authors.lastname: Echeverz
authors.affiliation: Laboratory of Microbial Biofilms, Instituto de Agrobiotecnología (Idab), Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Pamplona, Spain.
authors.forename: Begoña
authors.initials: B
authors.lastname: García
authors.affiliation: Laboratory of Microbial Biofilms, Instituto de Agrobiotecnología (Idab), Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Pamplona, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Gil
authors.affiliation: Laboratory of Microbial Biofilms, Instituto de Agrobiotecnología (Idab), Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Pamplona, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: García-Ona
authors.affiliation: Laboratory of Microbial Biofilms, Instituto de Agrobiotecnología (Idab), Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Pamplona, Spain.
authors.forename: Saioa
authors.initials: S
authors.lastname: Burgui
authors.affiliation: Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), Instituto de Investigación Sanitaria de Navarra (IdISNA), University of Navarra, Pamplona, Spain.
authors.forename: Noelia
authors.initials: N
authors.lastname: Casares
authors.affiliation: Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), Instituto de Investigación Sanitaria de Navarra (IdISNA), University of Navarra, Pamplona, Spain.
authors.forename: Sandra
authors.initials: S
authors.lastname: Hervás-Stubbs
authors.affiliation: Program of Immunology and Immunotherapy, Center for Applied Medical Research (CIMA), Instituto de Investigación Sanitaria de Navarra (IdISNA), University of Navarra, Pamplona, Spain.
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Lasarte
authors.affiliation: Laboratory of Microbial Biofilms, Instituto de Agrobiotecnología (Idab), Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Pamplona, Spain.|Navarrabiomed-Universidad Pública de Navarra, Instituto de Investigación Sanitaria de Navarra (IdISNA), Pamplona, Spain.
authors.forename: Iñigo
authors.initials: I
authors.lastname: Lasa
authors.affiliation: Laboratory of Microbial Biofilms, Instituto de Agrobiotecnología (Idab), Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Pamplona, Spain.
authors.forename: Cristina
authors.identifier: http://orcid.org/0000-0002-6207-1766
authors.initials: C
authors.lastname: Solano
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001426:Bacterial Proteins / Q000502:physiology*; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000172:deficiency; D005260:Female; D007371:Interferon-gamma / Q000097:blood; D016753:Interleukin-10 / Q000097:blood; D020381:Interleukin-17 / Q000097:blood; D007376:Interleukin-2 / Q000097:blood; D051379:Mice; D008807:Mice, Inbred BALB C; D012481:Salmonella Infections, Animal / Q000276:immunology / Q000517:prevention & control*; D022562:Salmonella Vaccines / Q000008:administration & dosage / Q000276:immunology / Q000627:therapeutic use*; D012486:Salmonella typhimurium / Q000276:immunology; D012808:Sigma Factor / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology / Q000627:therapeutic use
chemical_list: D001426:Bacterial Proteins; D020381:Interleukin-17; D007376:Interleukin-2; D022562:Salmonella Vaccines; D012808:Sigma Factor; D014409:Tumor Necrosis Factor-alpha; D014613:Vaccines, Attenuated; C069567:sigma factor KatF protein, Bacteria; D016753:Interleukin-10; C062025:bis(3',5')-cyclic diguanylic acid; D007371:Interferon-gamma; D006152:Cyclic GMP