Complement receptor
A complement receptor is a receptor of the complement system, part of the innate immune system. Complement receptors bind proteins of the complement system, and can thus detect pathogens without mediation by antibodies.[1] Complement activity can be triggered by specific antigen-antibody complexes, sugars or pathogens directly.
Complement receptor | |
---|---|
Identifiers | |
Symbol | Complement receptor |
Membranome | 116 |
Complement receptors
Many white blood cells express complement receptors on their surface, particularly monocytes and macrophages. All four complement receptors bind to fragments of complement component 3 or complement component 4 coated on pathogen surface, but the receptors have different functions. Complement receptor (CR) 1, 3, and 4 work as opsonins (stimulate phagocytosis), whereas CR2 is expressed only on B cells as a co-receptor.
Red blood cells (RBCs) also express CR1. With these receptors, RBCs bring antigen-antibody complexes bound to complement fragments in the blood to the liver and spleen for degradation.[2]
CR # | Name | Ligand[1] | CD |
CR1 | - | C3b, C4b, iC3b | CD35 |
CR2 | - | C3d, iC3b, C3dg, Epstein-Barr virus | CD21 |
CR3 | Macrophage-1 antigen or "integrin αMβ2" | iC3b | CD11b+CD18 |
CR4 | Integrin alphaXbeta2 or "p150,95" | iC3b | CD11c+CD18 |
- | C3a receptor | C3a | - |
- | C5a receptor | C5a | CD88 |
Clinical significance
Defects in these receptors can be associated with disease.[3]
See also
References
- Janeway, CA Jr; Travers P; Walport M; et al. (2001). "The complement system and innate immunity". Immunobiology: The Immune System in Health and Disease. New York: Garland Science. Retrieved 29 December 2017.
- Peter Parham, The Immune System (2nd ed.), Taylor&Francis
- "Complement Receptor Deficiency: eMedicine Dermatology". Retrieved 7 December 2010.
External links
- Complement+receptors at the US National Library of Medicine Medical Subject Headings (MeSH)