Abstract
Salmonella enterica serovar Gallinarum causes fowl typhoid, recognized worldwide as an economically important disease. The current vaccine, 9R, lacks a complete O antigen, which is a Salmonella virulence factor, and, in addition, has a number of other less well characterized chromosomal mutations. For optimal efficacy, 9R is administered by injection. In an effort to develop a vaccine suitable for oral administration, we constructed Salmonella Gallinarum strains with a reversible O-antigen phenotype. In this scenario, the vaccine strain produces full-length O antigen at the time it is administered to birds. After the vaccine has had time to colonize internal lymphoid tissues, the O-antigen is gradually lost, resulting in an attenuated strain. We found that strains carrying single mutations conferring this phenotype, δpmi and arabinose-regulated rfc, retained virulence. However, a mutant strain carrying both of these mutations was completely attenuated and immunogenic in chickens. This work demonstrates a novel approach for developing live Salmonella vaccines for poultry.
Original language | English (US) |
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Pages (from-to) | 52-56 |
Number of pages | 5 |
Journal | Avian diseases |
Volume | 59 |
Issue number | 1 |
DOIs | |
State | Published - Mar 1 2015 |
Keywords
- Salmonella Gallinarum
- chicken
- fowl typhoid
- live attenuated vaccine
- regulated O-antigen synthesis
ASJC Scopus subject areas
- Food Animals
- Animal Science and Zoology
- General Immunology and Microbiology