Detalle Publicación


Evaluation of a Salmonella strain lacking the secondary messenger C-di-GMP and RpoS as a live oral vaccine

Autores: Latasa, C.; Echeverz, M.; García, B.; Gil, C.; García-Ona, E.; Burgui, S.; Casares Lagar, Noelia; Hervas Stubbs, Sandra; Lasarte Sagastibelza, Juan José; Lasa, I. (Autor de correspondencia); Solano, C. (Autor de correspondencia)
Título de la revista: PLOS ONE
ISSN: 1932-6203
Volumen: 11
Número: 8
Páginas: e0161216
Fecha de publicación: 2016
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 ¿XIII, immunogenic enough to protect mice against a lethal oral challenge of a S. Typhimurium virulent strain. ¿XIII 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-¿, TNF-¿, IL-2, IL-17 and IL-10. ¿XIII was unable to form a biofilm and did not survive under desiccation conditions, indicating that it could be easily eliminated from the environment. Moreover, ¿XIII shows DIVA features that allow differentiation of infected and vaccinated animals. Altogether, these results show ¿XIII as a safe and effective live DIVA vaccine.