- Section 1 Patients and their treatment
- Section 2 Background to medicine
- Section 3 Cell biology
- Section 4 Immunological mechanisms
- 4.1 The innate immune system
- 4.2 The complement system
- 4.3 Adaptive immunity
- 4.4 Immunodeficiency
- 4.5 Allergy
- 4.6 Autoimmunity
- 4.7 Principles of transplantation immunology
- Section 5 Principles of clinical oncology
- Section 6 Old age medicine
- Section 7 Pain and palliative care
- Section 8 Infectious diseases
- Section 9 Sexually transmitted diseases
- Section 10 Environmental medicine, occupational medicine, and poisoning
- Section 11 Nutrition
- Section 12 Metabolic disorders
- Section 13 Endocrine disorders
- Section 14 Medical disorders in pregnancy
- Section 15 Gastroenterological disorders
- Section 16 Cardiovascular disorders
- Section 17 Critical care medicine
- Section 18 Respiratory disorders
- Section 19 Rheumatological disorders
- Section 20 Disorders of the skeleton
- Section 21 Disorders of the kidney and urinary tract
- Section 22 Haematological disorders
- Section 23 Disorders of the skin
- Section 24 Neurological disorders
- Section 25 Disorders of the eye
- Section 26 Psychiatric and drug-related disorders
- Section 27 Forensic medicine
- Section 28 Sport and exercise medicine
- Section 29 Biochemistry in medicine
- Section 30 Acute medicine
(p. 315) The complement system
- Chapter:
- (p. 315) The complement system
- Author(s):
Marina Botto
, and Matthew C. Pickering
- DOI:
- 10.1093/med/9780198746690.003.0039
The complement system, consisting of soluble and membrane-bound proteins, is a major effector mechanism of host defence against infection and inflammatory responses. It has an important role in the removal of immune complexes and dying cells, and also modulates humoral and cell-mediated immune responses. Complement activation occurs through three pathways, each generating enzyme complexes, termed C3 convertases. These cleave native C3 to form C3b and C3a. C3b can covalently attach to surfaces (e.g. pathogen surfaces) where it triggers biological responses following interaction with membrane-bound receptors and can also trigger cleavage of native C5 to C5b and C5a. C5b triggers the formation of the membrane attack complex, which disrupts target cell membrane integrity and may result in cell lysis.
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- Section 1 Patients and their treatment
- Section 2 Background to medicine
- Section 3 Cell biology
- Section 4 Immunological mechanisms
- 4.1 The innate immune system
- 4.2 The complement system
- 4.3 Adaptive immunity
- 4.4 Immunodeficiency
- 4.5 Allergy
- 4.6 Autoimmunity
- 4.7 Principles of transplantation immunology
- Section 5 Principles of clinical oncology
- Section 6 Old age medicine
- Section 7 Pain and palliative care
- Section 8 Infectious diseases
- Section 9 Sexually transmitted diseases
- Section 10 Environmental medicine, occupational medicine, and poisoning
- Section 11 Nutrition
- Section 12 Metabolic disorders
- Section 13 Endocrine disorders
- Section 14 Medical disorders in pregnancy
- Section 15 Gastroenterological disorders
- Section 16 Cardiovascular disorders
- Section 17 Critical care medicine
- Section 18 Respiratory disorders
- Section 19 Rheumatological disorders
- Section 20 Disorders of the skeleton
- Section 21 Disorders of the kidney and urinary tract
- Section 22 Haematological disorders
- Section 23 Disorders of the skin
- Section 24 Neurological disorders
- Section 25 Disorders of the eye
- Section 26 Psychiatric and drug-related disorders
- Section 27 Forensic medicine
- Section 28 Sport and exercise medicine
- Section 29 Biochemistry in medicine
- Section 30 Acute medicine