title: A Live Oral Fowl Typhoid Vaccine with Reversible O-Antigen Production.
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, Apmi 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.
authors: Arindam
authors: A
authors: Mitra
authors: Paweł
authors: P
authors: Łaniewski
authors: Roy
authors: R
authors: Curtiss
authors: Kenneth L
authors: KL
authors: Roland
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002645:Chickens; D009154:Mutation; D019081:O Antigens / Q000276:immunology*; D011201:Poultry Diseases / Q000382:microbiology / Q000517:prevention & control*; D012475:Salmonella / Q000145:classification / Q000235:genetics / Q000472:pathogenicity; D012481:Salmonella Infections, Animal / Q000276:immunology / Q000517:prevention & control*; D014436:Typhoid-Paratyphoid Vaccines / Q000008:administration & dosage / Q000276:immunology*; D014774:Virulence
chemical_list: D019081:O Antigens; D014436:Typhoid-Paratyphoid Vaccines