The AgI/II family adhesin AspA is required for respiratory infection by Streptococcus pyogenes

Linda Franklin, Angela H. Nobbs, Laura Bricio-Moreno, Christopher J Wright, Sarah E Maddocks, Jaspreet Singh Sahota, Joe Ralph, Matthew O'Connor, Howard F. Jenkinson, Aras Kadioglu*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

13 Citations (Scopus)

Abstract

Streptococcus pyogenes (GAS) is a human pathogen that causes pharyngitis and invasive diseases such as toxic shock syndrome and sepsis. The upper respiratory tract is the primary reservoir from which GAS can infect new hosts and cause disease. The factors involved in colonisation are incompletely known however. Previous evidence in oral streptococci has shown that the AgI/II family proteins are involved. We hypothesized that the AspA member of this family might be involved in GAS colonization. We describe a novel mouse model of GAS colonization of the nasopharynx and lower respiratory tract to elucidate these interactions. We used two clinical M serotypes expressing AspA, and their aspA gene deletant isogenic mutants in experiments using adherence assays to respiratory epithelium, macrophage phagocytosis and neutrophil killing assays and in vivo models of respiratory tract colonisation and infection. We demonstrated the requirement for AspA in colonization of the respiratory tract. AspA mutants were cleared from the respiratory tract and were deficient in adherence to epithelial cells, and susceptible to phagocytosis. Expression of AspA in the surrogate host Lactococcus lactis protected bacteria from phagocytosis. Our results suggest that AspA has an essential role in respiratory infection, and may function as a novel anti-phagocytic factor.

Original languageEnglish
Article number62433
Pages (from-to)e62433
Number of pages8
JournalPLoS ONE
Volume8
DOIs
Publication statusPublished - 30 Apr 2013

Keywords

  • GROUP-A STREPTOCOCCUS
  • BIOFILM FORMATION
  • EPITHELIAL-CELLS
  • M-PROTEIN
  • VACCINE DEVELOPMENT
  • SURFACE PROTEIN
  • C5A PEPTIDASE
  • MAC PROTEIN
  • BINDING
  • I/II

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