Salmonella enteritidis ghost vaccine induces effective protection against lethal challenge in specific-pathogen-free chicks.
Bacterial ghosts (BGs) are empty bacterial envelopes generated by expulsion of the bacterial genome and cytoplasmic contents from bacterial cells, and the process is mediated by lysis protein E encoded on bacteriophage PhiX174. BGs represent a new approach in vaccine development and have been applied to a variety of gram-negative bacterial vaccine candidates. In this study, a BG vaccine generated from Salmonella enteritidis (S. enteritidis) strain DH091 was prepared using the highly efficient plasmid, pBV-mE. The efficacy of the BG vaccine was tested using 75 chicks (Gallus gallus) kept under specific pathogen-free (SPF) conditions. A comprehensive evaluation of the immune response, including humoral and cellular immune responses, interferon-γ (IFN-γ) and interleukin-4 (IL-4) production, and histopathology of various tissues, was performed in BG-vaccinated animals subsequently challenged with S. enteritidis. The results were compared with animals that were immunized with the inactivated vaccine. S. enteritidis ghosts not only promoted the generation of high titer antibodies and IFN-γ and IL-4 production but also stimulated a significant increase in CD8(+) and CD4(+) T lymphocytes. In particular, the dramatic increase in CD8(+) T cells indicated that the vaccine was able to induce clearance of intracellular Salmonella. The protective effects of BG vaccination in SPF chicks against 5×10(9) colony forming units of S. enteritidis were a result of the induction of a more effective immune response than that observed with the inactivated vaccine. These findings demonstrate the potential of S. enteritidis ghosts to be used as effective vaccines.
State Key Laboratory of Veterinary Biotechnology, Division of Bacterial Diseases of Harbin Veterinary Research Institute of Chinese Academy of Agricultural Science, 427 Maduan Street, Harbin 150001, China.
Wei
W
Peng
Wei
W
Si
Lu
L
Yin
Huifang
H
Liu
Shenye
S
Yu
Siguo
S
Liu
Chunlai
C
Wang
Yuehong
Y
Chang
Zhuo
Z
Zhang
Shouping
S
Hu
Yanfen
Y
Du
D000818:Animals; D000907:Antibodies, Bacterial / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D001428:Bacterial Vaccines; D001433:Bacteriolysis; D010584:Bacteriophage phi X 174; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D049109:Cell Proliferation; D002478:Cells, Cultured; D002645:Chickens; D005822:Genetic Vectors / Q000235:genetics; D007110:Immunity, Active; D007371:Interferon-gamma / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D012477:Salmonella enteritidis / Q000276:immunology* / Q000472:pathogenicity; D014611:Vaccination
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D015847:Interleukin-4; D007371:Interferon-gamma