title: Characterization of a Salmonella Typhimurium ghost carrying an adjuvant protein as a vaccine candidate for the protection of chickens against virulent challenge.
abstract: In this study we describe the generation of a safe, immunogenic, genetically inactivated Salmonella Typhimurium ghost vaccine candidate carrying the Escherichia coli heat-labile enterotoxin B subunit (LTB) protein as an adjuvant molecule. An asd(+) p15A ori(-) plasmid pJHL187-LTB harbouring the E lysis gene cassette and a foreign antigen delivery cassette containing the eltB gene was used to transform a Δasd Salmonella Typhimurium (JOL1311) strain to construct the ghost strain, JOL1499. Incubation of mid-logarithmic phase JOL1499 cultures at 42°C resulted in co-expression of the eltB and E lysis genes, leading to the generation of Salmonella Typhimurium ghost cells carrying the LTB protein (Salmonella Typhimurium-LTB ghost). The production of LTB in Salmonella Typhimurium-LTB ghost preparations was confirmed by western blot analysis, and functional activity of the LTB protein to bind with GM1 receptors was determined by means of GM1 enzyme-linked immunosorbent assay. Efficacy of the Salmonella Typhimurium-LTB ghost as a vaccine candidate was evaluated in a chicken model using 56 chickens at 5 weeks old, which were divided into four groups (n = 14): group A was designated the non-vaccinated control group, whereas the birds in groups B, C, and D were immunized intramuscularly with 10(9), 10(8), and 10(7) ghost cells, respectively. Compared with the non-immunized chickens (group A), immunized chickens (groups B, C and D) exhibited increased titres of plasma IgG and intestinal secretory IgA antibodies. After oral challenge with 10(9) colony-forming units of a virulent Salmonella Typhimurium strain, the vaccinated group B birds showed a decrease in internal organ colonization with the challenge strain.
authors.affiliation: a College of Veterinary Medicine , Chonbuk National University , Jeonju , Republic of Korea.
authors.forename: Chetan V
authors.initials: CV
authors.lastname: Jawale
authors.forename: John Hwa
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000276:Adjuvants, Immunologic; D000818:Animals; D001427:Bacterial Toxins / Q000235:genetics / Q000276:immunology*; D002645:Chickens / Q000276:immunology*; D004768:Enterotoxins / Q000235:genetics / Q000276:immunology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000276:immunology*; D005260:Female; D015870:Gene Expression; D007070:Immunoglobulin A / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D011201:Poultry Diseases / Q000382:microbiology / Q000517:prevention & control*; D012481:Salmonella Infections, Animal / Q000382:microbiology / Q000517:prevention & control*; D012486:Salmonella typhimurium / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D014611:Vaccination / Q000662:veterinary*; D015164:Vaccines, Inactivated / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D015164:Vaccines, Inactivated; C027538:heat-labile enterotoxin, E coli