Complement inhibition by gram-positive pathogens: molecular mechanisms and therapeutic implications

The plasma proteins of the complement system are essential in the innate immune response against bacteria. Complement labels bacteria with opsonins to support phagocytosis and generates chemoattractants to attract phagocytes to the site of infection. In turn, bacterial human pathogens have evolved different strategies to specifically impair the complement response. Here, we review the large arsenal of complement inhibitors produced by the gram-positive pathogens Staphylococcus aureus and Group A Streptococcus. We discuss how these bacterial molecules provide us with new tools to treat both infectious and inflammatory disease conditions in humans.