Evasion proteins against mucosal immune Target Function/ effect on immune system Ref.
Staphylococcal superantigen-like protein-7 (SSL-7) SIgA It enhances the ability to colonize in mucosal environments such as the nasal passage by binding to SIgA. [28]
Evasion proteins against innate immune Target Function/ effect on immune system Ref.
Proteins including extracellular adherence protein (Eap), collagen-binding protein (Cna) and serine-aspartate repeat protein E (SdrE) C1q in classical pathway, lectin pathway, alternative pathway They inhibit the activation of the complement system by blocking these three pathways. [36-38]
Staphylococcal Protein A (SpA) IgG It results in the inverted tagging and blocking of the C1q binding sites, preventing complement initiation. [30]
B cells It interferes in B-cells activation and proliferation, reducing the phagocytosis of MRSA, impeding antibody production and causing disordered activation, finally leading to the death of the B cells. [44, 45]
Staphylococcal complement inhibitor (SCIN) C3 convertases It binds and stabilizes C3 convertases, interfering with the activation of the complement system. [32]
Extracellular fibrinogen-binding protein (Efb); its homolog extracellular complement-binding protein (Ecb) C3 They prevent C3 from recognition by macrophages. [33]
Second Immunoglobulin-binding protein (Sbi) IgG It avoids neutrophil-mediated opsonophagocytosis. [46]
C3 It binds to complement, leading to the cleavage and consumption of complement Factor C3. [34]
Factor I C3b It mediates C3b cleavage to iC3b, inhibiting initiation of the alternative pathway as well the activation of the terminal complement cascade. [35]
Staphylokinase (SAK) Complement It digests IgG and complement. [25]
chemotaxis inhibitory protein of staphylococci (CHIPS) C5aR It binds to C5aR to evade complement. [29]
FPR1 It binds to FPR1 to block the chemotaxis of neutrophils. [47]
Staphylococcal superantigen-like protein-7 (SSL-7) C5 It inhibits the opsonization of bacteria by inhibiting the cleavage of C5. [31]
Proteases, e.g., staphopain A (Scp A), aureolysin (Aur) Complement They degrade complement preventing opsonization and bacteria lysis. [30]
Neutrophils ScpA inhibits the chemotaxis and activation of neutrophils. [48]
Staphylococcal superantigen-like 5 (SSL5) P-selectin glycoprotein ligand 1 (PSGL-1) It binds to PSGL-1 of sialyl Lewis X, thus blocking PSGL-1 interaction with the natural ligand P-selectin and abrogating neutrophil rolling on endothelial cells. [39]
Proteins including extracellular adherence protein (Eap) Intercellular adhesion molecule 1 (ICAM-1) It binds to ICAM-1, blocking the neutrophil recruitment to the infection site. [32]
Staphylococcal complement inhibitor (SCIN), chemotaxis inhibitory protein of staphylococci (CHIPS) Neutrophils They impair neutrophil recruitment as chemotaxis inhibitors. [49]
Nuc NETs It is a nuclease produced by MRSA to evade NETs. [50, 51]
Panton-Valentine leukocidin (PVL) Neutrophils It causes neutrophil lysis at the dose of 0.04 µg/mL. [52]
Phenol-soluble-modulins (PSMs) Neutrophils They directly kill neutrophils mainly by disrupting the membrane. [41]