Salmonella enterica Serovar Enteritidis Ghosts Carrying the Escherichia coli Heat-Labile Enterotoxin B Subunit Are Capable of Inducing Enhanced Protective Immune Responses

Abstract

The Escherichia coli heat-labile enterotoxin B subunit (LTB) is a potent vaccine adjuvant. Salmonella enterica serovar Enteritidis ghosts carrying LTB (S. Enteritidis-LTB ghosts) were genetically constructed using a novel plasmid, pJHL187-LTB, designed for the coexpression of the LTB and E lysis proteins. S. Enteritidis-LTB ghosts were characterized using scanning electron microscopy to visualize their transmembrane tunnel structures. The expression of LTB in S. Enteritidis-LTB ghost preparations was confirmed by immunoblot and enzyme-linked immunosorbent assays. The parenteral adjuvant activity of LTB was demonstrated by immunizing chickens with either S. Enteritidis-LTB ghosts or S. Enteritidis ghosts. Chickens were intramuscularly primed at 5 weeks of age and subsequently boosted at 8 weeks of age. In total, 60 chickens were equally divided into three groups

Evaluation of immunogenicity and protective efficacy of adjuvantedSalmonellaTyphimurium ghost vaccine against salmonellosis in chickens

“…We utilized our previously constructed plasmid vector pJHL187-LTB carrying the regulatory E-lysis system and the foreign protein delivery system carrying the eltB gene (Jawale & Lee 2014b). For generation of a S. Typhimurium ghost carrying LTB adjuvant protein, the JOL1311 strain was transformed with plasmid pJHL187-LTB and the resultant strain was named JOL1499.…”

“…BGs maintain all surface proteins of the original bacterium in their original state and, therefore, possess all the structural, immunogenic, and bio-adhesive properties of the original bacterium (Eko et al 1999;Jawale & Lee 2014b); however, as the genetically inactivated BG cannot replicate inside the immunized host, it might subject to rapid clearance by the host (Desin et al 2013). Combination with a suitable adjuvant increases the persistence of the non-replicating BG antigens in order to induce long-lasting immune responses (Desin et al 2013).…”

Evaluation of Salmonella Gallinarum ghost formulated with Montanide™ ISA 70 VG adjuvant as a vaccine against fowl typhoid

“…The bacterial ghost cells were generated from the JOL1367 strain as described previously (Jawale and Lee, 2014a). The induction of gene E-mediated bacteriolysis Acta Veterinaria Hungarica 63, 2015 was monitored by measuring the optical density at 600-nm wavelength (OD600) and the colony-forming units (CFU) of viable cells at different lysis time-points.…”

“…Outer membrane protein fraction samples from S. Gallinarum-LTB ghosts and vector control strain ghost cells were prepared as described previously (Jawale and Lee, 2014a). Briefly, the S. Gallinarum-LTB ghost cells were resuspended in sterile PBS and subjected to sonication for 30 min.…”

“…More recently, we have demonstrated the vaccine potential of S. Gallinarum ghosts for protection against fowl typhoid (Chaudhari et al, 2012;Jawale and Lee, 2014b). The vaccine construction strategy incorporates a foreign immunomodulator protein such as Escherichia coli heat-labile enterotoxin B subunit (LTB) into the architecture of the ghost membrane, which may improve the immunogenic potential of the vaccine (Jawale and Lee, 2014a).…”