1. Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA 2. College of Animal Science and Technology, Southwest University, Chongqing, China
✉ Corresponding author: Qingke Kong, qingke.kongedu or kongqikicom, Tel/Fax: 352-294-4140
Citation:
Su H, Liu Q, Wang S, Curtiss R III, Kong Q. Regulated Delayed Shigella flexneri 2a O-antigen Synthesis in Live Recombinant Salmonella enterica Serovar Typhimurium Induces Comparable Levels of Protective Immune Responses with Constitutive Antigen Synthesis System. Theranostics 2019; 9(12):3565-3579. doi:10.7150/thno.33046. https://www.thno.org/v09p3565.htm
Shigella flexneri (S. flexneri), a leading cause of bacillary dysentery, is a major public health concern particularly affecting children in developing nations. We have constructed a novel attenuated Salmonella vaccine system based on the regulated delayed antigen synthesis (RDAS) and regulated delayed expression of attenuating phenotype (RDEAP) systems for delivering the S. flexneri 2a (Sf2a) O-antigen.
Methods: The new Salmonella vaccine platform was constructed through chromosomal integration of the araC PBAD lacI and araC PBAD wbaP cassettes, resulting in a gradual depletion of WbaP enzyme. An expression vector, encoding Sf2a O-antigen biosynthesis under the control of the LacI-repressible Ptrc promoter, was maintained in the Salmonella vaccine strain through antibiotic-independent selection. Mice immunized with the vaccine candidates were evaluated for cell-mediate and humoral immune responses.
Results: In the presence of exogenous arabinose, the Salmonella vaccine strain synthesized native Salmonella LPS as a consequence of WbaP expression. Moreover, arabinose supported LacI expression, thereby repressing Sf2a O-antigen production. In the absence of arabinose in vivo, native Salmonella LPS synthesis is repressed whilst the synthesis of the Sf2a O-antigen is induced. Murine immunization with the Salmonella vaccine strain elicited robust Sf2a-specific protective immune responses together with long term immunity.
Conclusion: These findings demonstrate the protective efficacy of recombinant Sf2a O-antigen delivered by a Salmonella vaccine platform.
Su, H., Liu, Q., Wang, S., Curtiss, R. III, Kong, Q. (2019). Regulated Delayed Shigella flexneri 2a O-antigen Synthesis in Live Recombinant Salmonella enterica Serovar Typhimurium Induces Comparable Levels of Protective Immune Responses with Constitutive Antigen Synthesis System. Theranostics, 9(12), 3565-3579. https://doi.org/10.7150/thno.33046.
ACS
Su, H.; Liu, Q.; Wang, S.; Curtiss, R. III; Kong, Q. Regulated Delayed Shigella flexneri 2a O-antigen Synthesis in Live Recombinant Salmonella enterica Serovar Typhimurium Induces Comparable Levels of Protective Immune Responses with Constitutive Antigen Synthesis System. Theranostics 2019, 9 (12), 3565-3579. DOI: 10.7150/thno.33046.
NLM
Su H, Liu Q, Wang S, Curtiss R III, Kong Q. Regulated Delayed Shigella flexneri 2a O-antigen Synthesis in Live Recombinant Salmonella enterica Serovar Typhimurium Induces Comparable Levels of Protective Immune Responses with Constitutive Antigen Synthesis System. Theranostics 2019; 9(12):3565-3579. doi:10.7150/thno.33046. https://www.thno.org/v09p3565.htm
CSE
Su H, Liu Q, Wang S, Curtiss R III, Kong Q. 2019. Regulated Delayed Shigella flexneri 2a O-antigen Synthesis in Live Recombinant Salmonella enterica Serovar Typhimurium Induces Comparable Levels of Protective Immune Responses with Constitutive Antigen Synthesis System. Theranostics. 9(12):3565-3579.
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