Evaluation of the Salmonella enterica Serovar Pullorum Pathogenicity Island 2 Mutant as a Candidate Live Attenuated Oral Vaccine.
Salmonella enterica serovar Pullorum (S. Pullorum) is a highly adapted pathogen that causes pullorum disease (PD), an important systemic disease of poultry that causes severe economic losses in developing countries. In the interests of developing a safe and immunogenic oral vaccine, the efficacy of a Salmonella pathogenicity island 2 (SPI2)-deleted mutant of S. Pullorum (S06004ΔSPI2) was evaluated in chickens. S06004ΔSPI2 was severely less virulent than the parental wild-type strain S06004 as determined by the 50% lethal dose (LD50) for 3-day-old chickens when injected intramuscularly. Two-day-old chickens immunized with a single oral dose of S06004ΔSPI2 showed no differences in body weight or clinical symptoms compared with those in the negative-control group. S06004ΔSPI2 bacteria were not isolated from livers or spleens of immunized chickens after a short period of time, and specific humoral and cellular immune responses were significantly induced. Immunized chickens were challenged with S. Pullorum strain S06004 and Salmonella enterica serovar Gallinarum (S. Gallinarum) strain SG9 at 10 days postimmunization (dpi), and efficient protection against the challenges was observed. None of the immunized chickens died, the clinical symptoms were slight and temporary following challenge in immunized chickens compared with those in the control group, and these chickens recovered by 3 to 5 dpi. Overall, these results demonstrate that S06004ΔSPI2 can be used as a live attenuated oral vaccine.
Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, People's Republic of China.
Junlei
J
Yin
Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, People's Republic of China.
Zhao
Z
Cheng
Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, People's Republic of China.
Xiaochun
X
Wang
Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, People's Republic of China.
Lijuan
L
Xu
Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, People's Republic of China.
Qiuchun
Q
Li
Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, People's Republic of China.
Shizhong
S
Geng
Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, Jiangsu, People's Republic of China jiao@yzu.edu.cn.
Xinan
X
Jiao
D000284:Administration, Oral; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D002645:Chickens; D064420:Drug-Related Side Effects and Adverse Reactions / Q000473:pathology; D044404:Genomic Islands; D007273:Injections, Intramuscular; D007928:Lethal Dose 50; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008099:Liver / Q000382:microbiology; D011201:Poultry Diseases / Q000276:immunology / Q000473:pathology / Q000517:prevention & control*; D012481:Salmonella Infections, Animal / Q000276:immunology / Q000473:pathology / Q000517:prevention & control*; D022562:Salmonella Vaccines / Q000008:administration & dosage / Q000009:adverse effects / Q000235:genetics / Q000276:immunology*; D019779:Salmonella enterica / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D017384:Sequence Deletion; D013154:Spleen / Q000382:microbiology; D016019:Survival Analysis; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000009:adverse effects / Q000235:genetics / Q000276:immunology; D014774:Virulence
D000907:Antibodies, Bacterial; D022562:Salmonella Vaccines; D014613:Vaccines, Attenuated