Attenuated Salmonella typhimurium delivering DNA vaccine encoding duck enteritis virus UL24 induced systemic and mucosal immune responses and conferred good protection against challenge

Vet Res. 2012 Jul 6;43(1):56. doi: 10.1186/1297-9716-43-56.


Orally delivered DNA vaccines against duck enteritis virus (DEV) were developed using live attenuated Salmonella typhimurium (SL7207) as a carrier and Escherichia coli heat labile enterotoxin B subunit (LTB) as a mucosal adjuvant. DNA vaccine plasmids pVAX-UL24 and pVAX-LTB-UL24 were constructed and transformed into attenuated Salmonella typhimurium SL7207 resulting SL7207 (pVAX-UL24) and SL7207 (pVAX-LTB-UL24) respectively. After ducklings were orally inoculated with SL7207 (pVAX-UL24) or SL7207 (pVAX-LTB-UL24), the anti-DEV mucosal and systemic immune responses were recorded. To identify the optimum dose that confers maximum protection, we used different doses of the candidate vaccine SL7207 (pVAX-LTB-UL24) during oral immunization. The strongest mucosal and systemic immune responses developed in the SL7207 (pVAX-LTB-UL24) (1011 CFU) immunized group. Accordingly, oral immunization of ducklings with SL7207 (pVAX-LTB-UL24) showed superior efficacy of protection (60-80%) against a lethal DEV challenge (1000 LD50), compared with the limited survival rate (40%) of ducklings immunized with SL7207 (pVAX-UL24). Our study suggests that the SL7207 (pVAX-LTB-UL24) can be a candidate DEV vaccine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic / genetics
  • Administration, Oral
  • Animals
  • Bacterial Toxins / genetics
  • Bacterial Toxins / metabolism
  • Dose-Response Relationship, Immunologic
  • Ducks*
  • Enterotoxins / genetics
  • Enterotoxins / metabolism
  • Escherichia coli / genetics
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism
  • Immunity, Mucosal
  • Mardivirus / immunology*
  • Marek Disease / immunology*
  • Marek Disease / virology
  • Plasmids / genetics
  • Poultry Diseases / immunology*
  • Poultry Diseases / virology
  • Random Allocation
  • Salmonella typhimurium / immunology
  • Vaccines, Attenuated / genetics
  • Vaccines, Attenuated / metabolism
  • Vaccines, DNA / genetics
  • Vaccines, DNA / metabolism
  • Viral Proteins
  • Viral Vaccines / genetics
  • Viral Vaccines / immunology*


  • Adjuvants, Immunologic
  • Bacterial Toxins
  • Enterotoxins
  • Escherichia coli Proteins
  • Vaccines, Attenuated
  • Vaccines, DNA
  • Viral Proteins
  • Viral Vaccines
  • heat-labile enterotoxin, E coli