title: An immunogenic Salmonella ghost confers protection against internal organ colonization and egg contamination.
abstract: The tightly regulated expression of the PhiX174 lysis gene E from a multi-copy plasmid led to the stable production of an Salmonella Enteritidis bacterial ghost. The present study was conducted to evaluate induction of the humoral and cell-mediated immune responses induced after single or double intramuscular immunization with the S. Enteritidis ghost and to assess its protective effect on colonization of the intestinal tract, visceral and reproductive organs, internal egg contamination, and egg production of laying chickens. A total of 60 chickens were equally divided into three groups (n=20); group A (non-immunized control), group B (immunized at 8 and 16 weeks of age) and group C (immunized at 16th week of age). Chickens from both immunized groups B and C demonstrated significant increases in plasma IgG, intestinal secretory IgA levels, and antigen-specific lymphocyte proliferative responses. The population of CD3+CD4+ positive T cells in the immunized chickens was also significantly increased after immunization and virulent challenge. In addition, the immunized groups B and C showed significantly higher egg production and a lower percentage of S. Enteritidis contaminated eggs after challenge compared to those of group A. A comparison of challenge strain isolation from the immunized-challenged and non-immunized-challenged layer hens showed that the double immunization group induced excellent protection against intestinal, liver, splenic, and ovarian Salmonella colonization; however, the single immunized chickens showed lower counts only in the splenic and ovarian organs. Overall, the data give compelling evidence that vaccination with the S. Enteritidis ghost induced robust protective immunity against experimental avian salmonellosis and may contribute to the reduce incidence of egg contamination.
authors.affiliation: College of Veterinary Medicine, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors.forename: Chetan V
authors.initials: CV
authors.lastname: Jawale
authors.affiliation: College of Veterinary Medicine, Chonbuk National University, Jeonju 561-756, Republic of Korea. Electronic address: johnhlee@jbnu.ac.kr.
authors.forename: John Hwa
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D002645:Chickens; D015169:Colony Count, Microbial / Q000662:veterinary; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004531:Eggs / Q000382:microbiology; D005260:Female; D007114:Immunization / Q000379:methods / Q000662:veterinary*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011201:Poultry Diseases / Q000276:immunology / Q000382:microbiology* / Q000517:prevention & control; D012481:Salmonella Infections, Animal / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control; D022562:Salmonella Vaccines / Q000008:administration & dosage / Q000276:immunology*; D012477:Salmonella enteritidis / Q000235:genetics / Q000276:immunology*; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D004269:DNA, Bacterial; D022562:Salmonella Vaccines; D015164:Vaccines, Inactivated
keywords: Bacterial ghost; CD4 T-cell response; Internal egg contamination; Protection; Salmonella Enteritidis