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Siggins MK, Lynskey NN, Lamb LE, Johnson LA, Huse KK, Pearson M, Banerji S, Turner CE, Woollard K, Jackson DG, Sriskandan S. Extracellular bacterial lymphatic metastasis drives Streptococcus pyogenes systemic infection. Nat Commun 2020; 11:4697. [PMID: 32943639 PMCID: PMC7498588 DOI: 10.1038/s41467-020-18454-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 08/24/2020] [Indexed: 12/15/2022] Open
Abstract
Unassisted metastasis through the lymphatic system is a mechanism of dissemination thus far ascribed only to cancer cells. Here, we report that Streptococcus pyogenes also hijack lymphatic vessels to escape a local infection site, transiting through sequential lymph nodes and efferent lymphatic vessels to enter the bloodstream. Contrasting with previously reported mechanisms of intracellular pathogen carriage by phagocytes, we show S. pyogenes remain extracellular during transit, first in afferent and then efferent lymphatics that carry the bacteria through successive draining lymph nodes. We identify streptococcal virulence mechanisms important for bacterial lymphatic dissemination and show that metastatic streptococci within infected lymph nodes resist and subvert clearance by phagocytes, enabling replication that can seed intense bloodstream infection. The findings establish the lymphatic system as both a survival niche and conduit to the bloodstream for S. pyogenes, explaining the phenomenon of occult bacteraemia. This work provides new perspectives in streptococcal pathogenesis with implications for immunity. Pathogenic agents can spread from an initial to a secondary site via the lymphatics. Here, using a mouse model of infection, the authors show that S. pyogenes readily transit through sequential lymph nodes within efferent lymphatics to reach the bloodstream and drive systemic infection, while remaining extracellular.
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Affiliation(s)
- Matthew K Siggins
- Department of Infectious Disease, Imperial College London, London, W12 0NN, UK. .,MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2DD, UK. .,NLHI, Imperial College London, London, W2 1PG, UK.
| | - Nicola N Lynskey
- Department of Infectious Disease, Imperial College London, London, W12 0NN, UK.,MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2DD, UK.,The Roslin Institute, University of Edinburgh, Edinburgh, EH25 9RG, UK
| | - Lucy E Lamb
- Department of Infectious Disease, Imperial College London, London, W12 0NN, UK
| | - Louise A Johnson
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Kristin K Huse
- Department of Infectious Disease, Imperial College London, London, W12 0NN, UK.,MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2DD, UK
| | - Max Pearson
- Department of Infectious Disease, Imperial College London, London, W12 0NN, UK.,MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2DD, UK
| | - Suneale Banerji
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Claire E Turner
- Department of Infectious Disease, Imperial College London, London, W12 0NN, UK.,The Florey Institute, University of Sheffield, Sheffield, S10 2TN, UK
| | - Kevin Woollard
- Centre for Inflammatory Disease, Department of Immunology & Inflammation, Imperial College London, London, W12 0NN, UK
| | - David G Jackson
- MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS, UK
| | - Shiranee Sriskandan
- Department of Infectious Disease, Imperial College London, London, W12 0NN, UK. .,MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2DD, UK.
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Rapid Lymphatic Dissemination of Encapsulated Group A Streptococci via Lymphatic Vessel Endothelial Receptor-1 Interaction. PLoS Pathog 2015; 11:e1005137. [PMID: 26352587 PMCID: PMC4564194 DOI: 10.1371/journal.ppat.1005137] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 08/10/2015] [Indexed: 11/29/2022] Open
Abstract
The host lymphatic network represents an important conduit for pathogen dissemination. Indeed, the lethal human pathogen group A streptococcus has a predilection to induce pathology in the lymphatic system and draining lymph nodes, however the underlying basis and subsequent consequences for disease outcome are currently unknown. Here we report that the hyaluronan capsule of group A streptococci is a crucial virulence determinant for lymphatic tropism in vivo, and further, we identify the lymphatic vessel endothelial receptor-1 as the critical host receptor for capsular hyaluronan in the lymphatic system. Interference with this interaction in vivo impeded bacterial dissemination to local draining lymph nodes and, in the case of a hyper-encapsulated M18 strain, redirected streptococcal entry into the blood circulation, suggesting a pivotal role in the manifestation of streptococcal infections. Our results reveal a novel function for bacterial capsular polysaccharide in directing lymphatic tropism, with potential implications for disease pathology. Pathogens are known to invade the host not only via the systemic circulation but also via the lymphatic network, however the mechanisms underlying the latter route and the consequences for disease outcome have not been well studied. The important human pathogen, group A streptococcus, is responsible for a number of clinical syndromes affecting both the lymphatic vessels and draining lymph nodes, such as lymphangitis and lymphadenitis. How such pathologies are orchestrated, and their significance in the development of serious infection are currently unknown. In this study, we show that the hyaluronan capsule secreted by group A streptococcus is critical for bacterial spread to draining lymph nodes, and we demonstrate that this occurs as a result of a specific interaction with the lymphatic vessel endothelial receptor-1. Genetic deletion or functional blockade of this receptor prevented streptococcal transit to draining lymph nodes in a murine model of infection, which in turn enhanced bacterial spread into the blood circulation. Together these results define a novel interaction between the group A streptococcal capsule and the lymphatic endothelial receptor-1 as a critical axis in the establishment of lymphatic tropism for this pathogen, with clear implications for disease severity in the host.
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