Salmonella enteritidis ghost vaccine induces effective protection against lethal challenge in specific-pathogen-free chicks

• Published in: Immunobiology (1979) 2011-05, Vol.216 (5), p.558-565
• Main Authors: Peng, Wei, Si, Wei, Yin, Lu, Liu, Huifang, Yu, Shenye, Liu, Siguo, Wang, Chunlai, Chang, Yuehong, Zhang, Zhuo, Hu, Shouping, Du, Yanfen
• Format: Article
• Language: English
• Subjects: Advanced Basic Science; Allergy and Immunology; Animals; Antibodies, Bacterial - metabolism; Bacterial Proteins - genetics; Bacterial Proteins - immunology; Bacterial Proteins - metabolism; Bacterial Vaccines; Bacteriolysis; Bacteriophage phi X 174; CD4-Positive T-Lymphocytes - immunology; CD4-Positive T-Lymphocytes - metabolism; CD4-Positive T-Lymphocytes - pathology; CD8-Positive T-Lymphocytes - immunology; CD8-Positive T-Lymphocytes - metabolism; CD8-Positive T-Lymphocytes - pathology; Cell Proliferation; Cells, Cultured; Chickens; Gallus gallus; Genetic Vectors - genetics; Ghost vaccine; Humoral and cellular immunity; Immune protection; Immunity, Active; Interferon-gamma - secretion; Interleukin-4 - secretion; Salmonella enteritidis; Salmonella enteritidis - immunology; Salmonella enteritidis - pathogenicity; Vaccination
• ISSN: 0171-2985; 1878-3279
• DOI: 10.1016/j.imbio.2010.10.001

Abstract 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 × 109 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.