• Medientyp: E-Artikel
  • Titel: M1 Protein-Dependent Intracellular Trafficking Promotes Persistence and Replication of Streptococcus pyogenes in Macrophages
  • Beteiligte: Hertzén, Erika; Johansson, Linda; Wallin, Robert; Schmidt, Heike; Kroll, Mirko; Rehn, Anders P.; Kotb, Malak; Mörgelin, Matthias; Norrby-Teglund, Anna
  • Erschienen: S. Karger AG, 2010
  • Erschienen in: Journal of Innate Immunity
  • Sprache: Englisch
  • DOI: 10.1159/000317635
  • ISSN: 1662-811X; 1662-8128
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  • Beschreibung: <jats:p>&lt;i&gt;Streptococcus pyogenes&lt;/i&gt; is an important human pathogen that causes a variety of diseases including life-threatening invasive diseases, such as toxic shock and deep tissue infections. Although &lt;i&gt;S. pyogenes&lt;/i&gt; are classically considered extracellular pathogens, a clinical significance of an intracellular source has been emphasized. In patients with deep tissue infections, an intracellular reservoir of &lt;i&gt;S. pyogenes&lt;/i&gt; within macrophages was shown to contribute to prolonged bacterial persistence. Here we demonstrate that intracellular survival of &lt;i&gt;S. pyogenes&lt;/i&gt; in macrophages is associated with an M1 protein-dependent intracellular trafficking in the phagosomal-lysosomal pathway, which results in impaired fusion with lysosomes. The phagocytic vacuoles harbouring M1 protein-expressing bacteria not only served as a safe haven for the bacteria, but also as a replicating niche. An M1 protein-dependent modulation of macrophages was further supported by differences in NF-ĸB signalling between cells infected with either the wild-type or M1 protein-deficient strains, thereby indicating a suppressed inflammatory response when M1 protein was involved. Evidence of egress of bacteria out of their host cell and subsequent re-infection of new cells emphasize the importance of intracellular bacteria as a reservoir for dissemination of infection and continued tissue injury.</jats:p>
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