Staphylococcal superantigen-like protein 13 activates neutrophils via formyl peptide receptor 2

Cell Microbiol. 2018 Nov;20(11):e12941. doi: 10.1111/cmi.12941. Epub 2018 Sep 17.


Staphylococcal superantigen-like (SSL) proteins, one of the major virulence factor families produced by Staphylococcus aureus, were previously demonstrated to be immune evasion molecules that interfere with a variety of innate immune defences. However, in contrast to characterised SSLs, which inhibit immune functions, we show that SSL13 is a strong activator of neutrophils via the formyl peptide receptor 2 (FPR2). Moreover, our data show that SSL13 acts as a chemoattractant and induces degranulation and oxidative burst in neutrophils. As with many other staphylococcal immune evasion proteins, SSL13 shows a high degree of human specificity. SSL13 is not able to efficiently activate mouse neutrophils, hampering in vivo experiments. In conclusion, SSL13 is a neutrophil chemoattractant and activator that acts via FPR2. Therefore, SSL13 is a unique SSL member that does not belong to the immune evasion class but is a pathogen alarming molecule. Our study provides a new concept of SSLs; SSLs not only inhibit host immune processes but also recruit human neutrophils to the site of infection. This new insight allows us to better understand complex interactions between host and S. aureus pathological processes.

Keywords: FPR2; SSL13; Staphylococcus aureus; activation; neutrophils.

MeSH terms

  • Animals
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Cell Degranulation
  • Chemotactic Factors / metabolism
  • Female
  • HL-60 Cells
  • Humans
  • Immune Evasion
  • Mice, Inbred Strains
  • Neutrophil Activation
  • Neutrophils / microbiology*
  • Neutrophils / physiology
  • Peritonitis / metabolism
  • Peritonitis / microbiology
  • Receptors, Formyl Peptide / metabolism*
  • Receptors, Lipoxin / metabolism*
  • Respiratory Burst
  • Staphylococcal Infections / microbiology
  • Staphylococcal Infections / pathology
  • Staphylococcus aureus / pathogenicity*
  • Virulence Factors / metabolism*


  • Bacterial Proteins
  • Chemotactic Factors
  • FPR2 protein, human
  • Receptors, Formyl Peptide
  • Receptors, Lipoxin
  • Virulence Factors