Vaccines to Control Salmonella in Poultry.

This review is focused on describing and analyzing means by which Salmonella enterica serotype strains have been genetically modified with the purpose of developing safe, efficacious vaccines to present Salmonella-induced disease in poultry and to prevent Salmonella colonization of poultry to reduce transmission through the food chain in and on eggs and poultry meat. Emphasis is on use of recently developed means to generate defined deletion mutations to eliminate genetic sequences conferring antimicrobial resistance or residual elements that might lead to genetic instability. Problems associated with prior means to develop vaccines are discussed with presentation of various means by which these problems have been lessened, if not eliminated. Practical considerations are also discussed in hope of facilitating means to move lab-proven successful vaccination procedures and vaccine candidates to the marketplace to benefit the poultry industry.

Estudio recapitulativo- Vacunas para controlar Salmonella en la avicultura. Esta revisión se centra en describir y analizar los medios mediante los cuales las cepas de serotipo de Salmonella enterica han sido modificadas genéticamente con el propósito de desarrollar vacunas seguras y eficaces para proteger contra la enfermedad inducida por Salmonella en la avicultura y prevenir la colonización de las aves por Salmonella para reducir la transmisión a través de la cadena alimentaria por la contaminación en el interior y exterior del huevo y en los productos cárnicos de origen avícola. Se hace hincapié en el uso de medios desarrollados recientemente para generar mutaciones definidas de deleción para eliminar secuencias genéticas que confieren resistencia contra los antimicrobianos o elementos residuales que podrían conducir a inestabilidad genética. Se analizan los problemas asociados con los medios anteriores para desarrollar vacunas y se presentan diversos medios mediante los cuales estos problemas se han reducido, si no eliminado. También se discuten las consideraciones prácticas para facilitar medios para transferir a condiciones comerciales y de mercado, los procedimientos de vacunación y candidatos a vacunas que han sido exitosos mediante pruebas en el lab-oratorio para beneficiar a la industria avícola.

Salmonella typhimurium Vaccine Candidate Delivering Infectious Bronchitis Virus S1 Protein to Induce Protection.

Infectious bronchitis (IB) is a highly infectious viral disease of chickens which causes significant economic losses in the poultry industry worldwide. An effective vaccine against IB is urgently needed to provide both biosafety and high-efficiency immune protection. In this study, the S1 protein of the infectious bronchitis virus was delivered by a recombinant attenuated Salmonella typhimurium vector to form the vaccine candidate χ11246(pYA4545-S1). S. typhimurium χ11246 carried a sifA- mutation with regulated delayed systems, striking a balance between host safety and immunogenicity. Here, we demonstrated that S1 protein is highly expressed in HD11 cells. Immunization with χ11246(pYA4545-S1) induced the production of antibody and cytokine, leading to an effective immune response against IB. Oral immunization with χ11246(pYA4545-S1) provided 72%, 56%, and 56% protection in the lacrimal gland, trachea, and cloaca against infectious bronchitis virus infection, respectively. Furthermore, it significantly reduced histopathological lesions in chickens. Together, this study provides a new idea for the prevention of IB.

A bacterial vesicle-based pneumococcal vaccine against influenza-mediated secondary Streptococcus pneumoniae pulmonary infection.

Streptococcus pneumoniae (Spn) is a common pathogen causing a secondary bacterial infection following influenza, which leads to severe morbidity and mortality during seasonal and pandemic influenza. Therefore, there is an urgent need to develop bacterial vaccines that prevent severe post-influenza bacterial pneumonia. Here, an improved Yersinia pseudotuberculosis strain (designated as YptbS46) possessing an Asd+ plasmid pSMV92 could synthesize high amounts of the Spn pneumococcal surface protein A (PspA) antigen and monophosphoryl lipid A as an adjuvant. The recombinant strain produced outer membrane vesicles (OMVs) enclosing a high amount of PspA protein (designated as OMV-PspA). A prime-boost intramuscular immunization with OMV-PspA induced both memory adaptive and innate immune responses in vaccinated mice, reduced the viral and bacterial burden, and provided complete protection against influenza-mediated secondary Spn infection. Also, the OMV-PspA immunization afforded significant cross-protection against the secondary Spn A66.1 infection and long-term protection against the secondary Spn D39 challenge. Our study implies that an OMV vaccine delivering Spn antigens can be a new promising pneumococcal vaccine candidate.