sopB of Salmonella enterica serovar Typhimurium is a potential DNA vaccine candidate in conjugation with live attenuated bacteria

• Published in: Vaccine Vol. 27; no. 21; pp. 2804 - 2811
• Main Authors: Nagarajan, Arvindhan G, Balasundaram, Sudhagar V, Janice, Jessin, Karnam, Guruswamy, Eswarappa, Sandeepa M, Chakravortty, Dipshikha
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 11.05.2009; Elsevier
• Subjects: Allergy and Immunology; Animals; Applied microbiology; Bacterial Proteins - genetics; Bacterial Proteins - immunology; Bacterial Vaccines - immunology; Bacteriology; Biological and medical sciences; CD4-Positive T-Lymphocytes - cytology; CD4-Positive T-Lymphocytes - immunology; CD8-Positive T-Lymphocytes - cytology; CD8-Positive T-Lymphocytes - immunology; Computational Biology; DNA vaccine; Female; Fundamental and applied biological sciences. Psychology; Histocompatibility Antigens Class I - immunology; Histocompatibility Antigens Class II - immunology; Interferon-gamma - blood; Interferon-gamma - immunology; Lymphocyte Count; Mice; Mice, Inbred BALB C; Microbiology; Miscellaneous; Salmonella; Salmonella enterica; Salmonella Infections - immunology; Salmonella Infections - microbiology; Salmonella Infections - prevention & control; Salmonella typhimurium - genetics; Salmonella typhimurium - immunology; SopB; Spleen - cytology; Spleen - immunology; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies (general aspects); Vaccines, Attenuated - immunology; Vaccines, DNA - genetics; Vaccines, DNA - immunology; DNA vaccine; Salmonella; SopB; Bacteria; Conjugation; Attenuated strain; Genetic vaccine; Salmonella typhimurium; Enterobacteriaceae
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/j.vaccine.2009.02.092

Abstract The immune response against Salmonella is multi-faceted involving both the innate and the adaptive immune system. The characterization of specific Salmonella antigens inducing immune response could critically contribute to the development of epitope based vaccines for Salmonella . We have tried to identify a protective T cell epitope(s) of Salmonella , as cell mediated immunity conferred by CD8+ T cells is the most crucial subset conferring protective immunity against Salmonella . It being a proven fact that secreted proteins are better in inducing cell mediated immunity than cell surface and cytosolic antigens, we have analyzed all the genbank annotated Salmonella pathogenicity island 1 and 2 secreted proteins of Salmonella enterica serovar Typhimurium ( S. typhimurium ) and S. enterica serovar Typhi ( S. typhi ). They were subjected to BIMAS and SYFPEITHI analysis to map MHC-I and MHC-II binding epitopes. The huge profile of possible T cell epitopes obtained from the two classes of secreted proteins were tabulated and using a scoring system that considers the binding affinity and promiscuity of binding to more than one allele, SopB and SifB were chosen for experimental confirmation in murine immunization model. The entire SopB and SifB genes were cloned into DNA vaccine vectors and were administered along with live attenuated Salmonella and it was found that SopB vaccination reduced the bacterial burden of organs by about 5-fold on day 4 and day 8 after challenge with virulent Salmonella and proved to be a more efficient vaccination strategy than live attenuated bacteria alone.