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Sang S, Song W, Lu L, Ou Q, Guan Y, Tao H, Wang Y, Liu C. The Trimeric Autotransporter Adhesin SadA from Salmonella spp. as a Novel Bacterial Surface Display System. Vaccines (Basel) 2024; 12:399. [PMID: 38675781 PMCID: PMC11054257 DOI: 10.3390/vaccines12040399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 03/25/2024] [Accepted: 03/26/2024] [Indexed: 04/28/2024] Open
Abstract
Bacterial surface display platforms have been developed for applications such as vaccine delivery and peptide library screening. The type V secretion system is an attractive anchoring motif for the surface expression of foreign proteins in gram-negative bacteria. SadA belongs to subtype C of the type V secretion system derived from Salmonella spp. and promotes biofilm formation and host cell adherence. The inner membrane lipoprotein SadB is important for SadA translocation. In this study, SadA was used as an anchoring motif to expose heterologous proteins in Salmonella typhimurium using SadB. The ability of SadA to display heterologous proteins on the S. typhimurium surface in the presence of SadB was approximately three-fold higher than that in its absence of SadB. Compared to full-length SadA, truncated SadAs (SadA877 and SadA269) showed similar display capacities when exposing the B-cell epitopes of urease B from Helicobacter pylori (UreB158-172aa and UreB349-363aa). We grafted different protein domains, including mScarlet (red fluorescent protein), the urease B fragment (UreBm) from H. pylori SS1, and/or protective antigen domain 4 from Bacillus anthracis A16R (PAD4), onto SadA877 or SadA1292. Whole-cell dot blotting, immunofluorescence, and flow cytometric analyses confirmed the localization of Flag×3-mScarlet (~30 kDa) and Flag×3-UreBm-mScarlet (~58 kDa) to the S. typhimurium surface using truncated SadA877 or SadA1292 as an anchoring motif. However, Flag×3-UreBm-PAD4-mScarlet (~75 kDa) was displayed on S. typhimurium using SadA1292. The oral administrated pSadBA1292-FUM/StmΔygeAΔmurI and pSadBA877-FUM/StmΔygeAΔmurI could elicit a significant mucosal and humoral immunity response. SadA could thus be used as an anchoring motif for the surface expression of large heterologous proteins as a potential strategy for attenuated bacterial vaccine development.
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Affiliation(s)
- Shuli Sang
- State Key Laboratory of Pathogen and Biosecurity, Institute of Biotechnology, Academy of Military Medical Sciences, 20 Dongda Street, Fengtai District, Beijing 100071, China; (S.S.); (W.S.); (L.L.); (Q.O.); (Y.G.); (H.T.)
| | - Wenge Song
- State Key Laboratory of Pathogen and Biosecurity, Institute of Biotechnology, Academy of Military Medical Sciences, 20 Dongda Street, Fengtai District, Beijing 100071, China; (S.S.); (W.S.); (L.L.); (Q.O.); (Y.G.); (H.T.)
| | - Lu Lu
- State Key Laboratory of Pathogen and Biosecurity, Institute of Biotechnology, Academy of Military Medical Sciences, 20 Dongda Street, Fengtai District, Beijing 100071, China; (S.S.); (W.S.); (L.L.); (Q.O.); (Y.G.); (H.T.)
| | - Qikun Ou
- State Key Laboratory of Pathogen and Biosecurity, Institute of Biotechnology, Academy of Military Medical Sciences, 20 Dongda Street, Fengtai District, Beijing 100071, China; (S.S.); (W.S.); (L.L.); (Q.O.); (Y.G.); (H.T.)
- School of Basic Medical Sciences, Guangxi Medical University, 22 Shuangyong Road, Nanning 530021, China
| | - Yiyan Guan
- State Key Laboratory of Pathogen and Biosecurity, Institute of Biotechnology, Academy of Military Medical Sciences, 20 Dongda Street, Fengtai District, Beijing 100071, China; (S.S.); (W.S.); (L.L.); (Q.O.); (Y.G.); (H.T.)
| | - Haoxia Tao
- State Key Laboratory of Pathogen and Biosecurity, Institute of Biotechnology, Academy of Military Medical Sciences, 20 Dongda Street, Fengtai District, Beijing 100071, China; (S.S.); (W.S.); (L.L.); (Q.O.); (Y.G.); (H.T.)
| | - Yanchun Wang
- State Key Laboratory of Pathogen and Biosecurity, Institute of Biotechnology, Academy of Military Medical Sciences, 20 Dongda Street, Fengtai District, Beijing 100071, China; (S.S.); (W.S.); (L.L.); (Q.O.); (Y.G.); (H.T.)
| | - Chunjie Liu
- State Key Laboratory of Pathogen and Biosecurity, Institute of Biotechnology, Academy of Military Medical Sciences, 20 Dongda Street, Fengtai District, Beijing 100071, China; (S.S.); (W.S.); (L.L.); (Q.O.); (Y.G.); (H.T.)
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