Formyl-Peptide Receptor Activation Enhances Phagocytosis of Community-Acquired Methicillin-Resistant Staphylococcus aureus.

Background: Formyl-peptide receptors (FPRs) are important pattern recognition receptors that sense specific bacterial peptides. Formyl-peptide receptors are highly expressed on neutrophils and monocytes, and their activation promotes the migration of phagocytes to sites of infection. It is currently unknown whether FPRs may also influence subsequent processes such as bacterial phagocytosis and killing. Staphylococcus aureus, especially highly pathogenic community-acquired methicillin-resistant S aureus strains, release high amounts of FPR2 ligands, the phenol-soluble modulins.

Methods: We demonstrate that FPR activation leads to upregulation of complement receptors 1 and 3 as well as FCγ receptor I on neutrophils and, consequently, increased opsonic phagocytosis of S aureus and other pathogens.

Results: Increased phagocytosis promotes killing of S aureus and interleukin-8 release by neutrophils.

Conclusions: We show here for the first time that FPRs govern opsonic phagocytosis. Manipulation of FPR2 activation could open new therapeutic opportunities against bacterial pathogens.