Complement and Bacterial Infections: From Molecular Mechanisms to Therapeutic Applications

J Innate Immun. 2018;10(5-6):455-464. doi: 10.1159/000491439. Epub 2018 Aug 27.


Complement is a complex protein network of plasma, and an integral part of the innate immune system. Complement activation results in the rapid clearance of bacteria by immune cells, and direct bacterial killing via large pore-forming complexes. Here we review important recent discoveries in the complement field, focusing on interactions relevant for the defense against bacteria. Understanding the molecular interplay between complement and bacteria is of great importance for future therapies for infectious and inflammatory diseases. Antibodies that support complement-dependent bacterial killing are of interest for the development of alternative therapies to treat infections with antibiotic-resistant bacteria. Furthermore, a variety of novel therapeutic complement inhibitors have been developed to prevent unwanted complement activation in autoimmune inflammatory diseases. A better understanding of how such inhibitors may increase the risk of bacterial infections is essential if such therapies are to be successful.

Keywords: Antibiotic resistance; Antibody therapy; Bacteria; Complement; Eculizumab; Infections; Inflammatory diseases; Membrane attack complex; Neisseria.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Anti-Bacterial Agents / therapeutic use
  • Antibody-Dependent Cell Cytotoxicity
  • Autoimmune Diseases / immunology*
  • Bacterial Infections / drug therapy
  • Bacterial Infections / immunology*
  • Complement Activation
  • Complement Inactivator Proteins / therapeutic use
  • Complement System Proteins / metabolism*
  • Drug Resistance
  • Host-Pathogen Interactions
  • Humans
  • Phagocytosis


  • Anti-Bacterial Agents
  • Complement Inactivator Proteins
  • Complement System Proteins