Antigen Localization Influences the Magnitude and Kinetics of Endogenous Adaptive Immune Response to Recombinant Salmonella Vaccines


The use of recombinant attenuated Salmonella vaccine (RASV) strains is a promising strategy for presenting heterologous antigens to the mammalian immune system to induce both cellular and humoral immune responses. However, studies on RASV development differ on where heterologous antigens are expressed and localized within the bacterium, and it is unclear how antigen localization modulates the immune response. Previously, we exploited the plasmid-encoded toxin (Pet) autotransporter system for accumulation of heterologous antigens in cell culture supernatant. In the present study, this Pet system was used to express early secretory antigen 6 (ESAT-6), an immunodominant and diagnostic antigen from Mycobacterium tuberculosis, in Salmonella enterica serovar Typhimurium strain SL3261. Three strains were generated, whereby ESAT-6 was expressed as a cytoplasmic (SL3261/cyto), surface-bound (SL3261/surf), or secreted (SL3261/sec) antigen. Using these RASVs, the relationship between antigen localization and immunogenicity in infected C57BL/6 mice was systematically examined. Using purified antigen and specific tetramers, we showed that mice infected with the SL3261/surf or SL3261/sec strain generated large numbers of Th1 CD4+ ESAT-6+ splenic T cells compared to those of mice infected with SL3261/cyto. While all mice showed ESAT-6-specific antibody responses when infected with SL3261/surf or SL3261/sec, peak total serum IgG antibody titers were reached more rapidly in mice that received SL3261/sec. Thus, how antigen is localized after production within bacteria has a more marked effect on the antibody response than on the CD4+ T cell response, which might influence the chosen strategy to localize recombinant antigen in RASVs.

Publication DOI:
Divisions: College of Health & Life Sciences > School of Biosciences
College of Health & Life Sciences
Funding Information: We acknowledge the NIH Tetramer Core Facility (contract HHSN272201300006C) for provision of the MHC I-A(b) M. tuberculosis ESAT-6 1-20 (MTEQQWNFAGIEAAASAIQG) and 4-17 (QQWNFAGIEAAASA) tetramers. This work was funded by a Wellcome Trust Sir Henry Wellcome
Additional Information: © Crown copyright 2017. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.
Uncontrolled Keywords: Adaptive Immunity,Animals,Antibodies, Bacterial/blood,Antigens, Bacterial/genetics,Bacterial Proteins/genetics,Mice, Inbred C57BL,Plasmids,Salmonella Vaccines/genetics,Salmonella typhimurium/genetics,T-Lymphocytes/immunology,Tuberculosis Vaccines/genetics,Vaccines, Synthetic/genetics,Parasitology,Microbiology,Immunology,Infectious Diseases
Publication ISSN: 1098-5522
Last Modified: 03 Jul 2024 07:10
Date Deposited: 28 Aug 2019 13:50
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Related URLs: https://iai.asm ... 17/article-info (Publisher URL)
PURE Output Type: Article
Published Date: 2017-11-17
Accepted Date: 2017-08-19
Authors: Sevastsyanovich, Yanina R
Withers, David R
Marriott, Claire L
Morris, Faye C
Wells, Timothy J
Browning, Douglas F (ORCID Profile 0000-0003-4672-3514)
Beriotto, Irene
Ross, Ewan (ORCID Profile 0000-0001-5733-9361)
Ali, Hossam Omar
Wardius, Catherine A
Cunningham, Adam F
Henderson, Ian R
Rossiter, Amanda E



Version: Published Version

License: Creative Commons Attribution

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