PbsP,a cell wall‐anchored protein that binds plasminogen to promote hematogenous dissemination of group B Streptococcus |
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| Authors: | Marco Buscetta Arnaud Firon Giampiero Pietrocola Carmelo Biondo Giuseppe Mancuso Angelina Midiri Letizia Romeo Roberta Galbo Mario Venza Isabella Venza Pierre‐Alexandre Kaminski Myriam Gominet Giuseppe Teti Pietro Speziale Patrick Trieu‐Cuot Concetta Beninati |
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| Institution: | 1. Metchnikoff Laboratory, Departments of Human Pathology and Medicine, University of Messina, Messina, Italy;2. Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram Positif, Paris, France;3. Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Pavia, Italy;4. Scylla Biotech Srl, Messina, Italy |
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| Abstract: | Streptococcus agalactiae (Group B Streptococcus or GBS) is a leading cause of invasive infections in neonates whose virulence is dependent on its ability to interact with cells and host components. We here characterized a surface protein with a critical function in GBS pathophysiology. This adhesin, designated PbsP, possesses two Streptococcal Surface Repeat domains, a methionine and lysine‐rich region, and a LPXTG cell wall‐anchoring motif. PbsP mediates plasminogen (Plg) binding both in vitro and in vivo and we showed that cell surface‐bound Plg can be activated into plasmin by tissue plasminogen activator to increase the bacterial extracellular proteolytic activity. Absence of PbsP results in a decreased bacterial transmigration across brain endothelial cells and impaired virulence in a murine model of infection. PbsP is conserved among the main GBS lineages and is a major plasminogen adhesin in non‐CC17 GBS strains. Importantly, immunization of mice with recombinant PbsP confers protective immunity. Our results indicate that GBS have evolved different strategies to recruit Plg which indicates that the ability to acquire cell surface proteolytic activity is essential for the invasiveness of this bacterium. |
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