II. Physiology: General

  1. Complement are components of both Innate Immunity and the humoral Immune System
  2. Multiple triggers including Antigen-Antibody complex as well as direct exposure to pathogen (see activation below)
  3. Results in inflammatory response (Chemoattractant), Phagocytosis (as Opsonin on cell surface) and pathogen lysis
  4. Solubilizes immune complexes to aid in clearance

III. Physiology: Complement Pathway

  1. Images
    1. idComplementPathway.jpg
  2. Activation
    1. Classical Pathway (C1, C2, C3, C4)
      1. C1q binds Antigen-Antibody complex
      2. C1r and C1s are activated and bind C1q (and Antigen-Antibody complex)
      3. C1 complex (C1q, C1r, C1s) acts on C2 and C4, resulting in C4b2a which activates C3
      4. Classical Pathway is regulated by C1 Esterase Inhibitor which dissociates C1r/s from C1q
    2. Alternate Pathway (Properdin, Factor B, Factor D, C3)
      1. Activation via microbe cell surface
    3. Lectin Pathway (Mannose Binding Lectin or MBL)
      1. Mannose Binding Lectin (MBL) binds mannose on microbe surface
      2. Mannose Binding Lectin Associated Proteases (MASP-1, MASP-2) are activated
      3. Classical Pathway (above) is stimulated
  3. Enzyme C3 Convertase (C3bBb or C4b2a) Formation
    1. Enzyme C3 Convertase splits C3 into C3a and C3b
    2. C3a stimulates inflammation (attracts Neutrophils, histamine release)
    3. C3b stimulates Phagocytosis, inflammation (as with C3) and lysis (see below)
  4. Opsonization
    1. Microbe coated with an Opsonin such as an Antibody or complement (e.g. C3b)
    2. Surface Opsonins target microbes for Phagocytosis
  5. Phagocytosis
    1. Phagocytes such as Neutrophils (PMNs) and Macrophages attract and engulf targeted organisms
  6. Inflammation (via C3a, C5a)
    1. Chemoattraction of Neutrophils
    2. Anaphylatoxic activation of Mast Cells and Basophils to degranulate, releasing histamines and vasoactives
      1. Inflammation occurs when histamine-induced capillary dilation results in fluid and protein release
  7. Lysis
    1. C3b splits C5 into C5a and C5b
    2. Membrane attack complex or MAC (C5b, C6, C7, C8, C9) binds microbe surface
    3. MAC promotes microbe lysis

IV. Labs

  1. Complement C3
    1. Marker for Intrinsic and Extrinsic Pathway Function
    2. Measured by immunochemical assay
  2. Complement C4
    1. Marker for Intrinsic Pathway Function
    2. Measured by immunochemical assay
    3. Deficient in 1% of population
    4. Deficient in 11% with Systemic Lupus Erythematosus
  3. Complement CH50
    1. Marker for function of entire intrinsic cascade
    2. Measured by serum ability to lyse IgG coated RBCs
      1. Most affected by delay in performing assay

V. Causes: Low Complement levels indicate depletion

  1. Rheumatic causes
    1. Systemic Lupus Erythematosus
    2. Mixed Connective Tissue Disease (MCTD)
    3. Vasculitis (especially cryoglobulinemia)
  2. Non-Rheumatic Causes
    1. Septic Shock
    2. Liver failure
    3. Severe Malnutrition
    4. Pancreatitis
    5. Severe burns
    6. Atheromatous embolization

VI. Indications: Follow rheumatic disease activity

  1. Complement fall 20% below baseline signal exacerbation

VII. Associated Conditions: Complement Disorders (2% of Immunodeficiency disorders)

  1. Autoimmune Condition or Rheumatologic Condition (associated with C1-C4 deficiencies)
    1. Systemic Lupus Erythematosus
  2. Recurrent encapsulated organism, esp. pyogenic infections (manifestations vary depending on missing complement type)
    1. Complement deficiencies include C1q, C2-C9 (except C4), Factor I, Properdin
    2. Neisseria infections are most common including Meningitis, Sepsis and Arthritis (associated with C5-C9 deficiencies)
    3. Recurrent infections with Streptococcus Pneumoniae and HaemophilusInfluenzae (associated with C3 deficiency)
  3. Hereditary Angioedema
    1. C1 Esterase Inhibitor Deficiency

VIII. References

  1. Mahmoudi (2014) Immunology Made Ridiculously Simple, MedMaster, Miami, FL

Images: Related links to external sites (from Bing)

Related Studies

Ontology: Complement 3 (C0009506)

Definition (NCI) Complement C3 (1663 aa, ~187 kDa) is encoded by the human C3 gene. This protein plays a role in complement-mediated immunity.
Definition (MSH) A glycoprotein that is central in both the classical and the alternative pathway of COMPLEMENT ACTIVATION. C3 can be cleaved into COMPLEMENT C3A and COMPLEMENT C3B, spontaneously at low level or by C3 CONVERTASE at high level. The smaller fragment C3a is an ANAPHYLATOXIN and mediator of local inflammatory process. The larger fragment C3b binds with C3 convertase to form C5 convertase.
Concepts Amino Acid, Peptide, or Protein (T116) , Immunologic Factor (T129)
MSH D003176
SnomedCT 165930004, 143317000, 2676007, 10473000
LNC LP16359-9, MTHU005207
English Complement -third component-C3, Complement component 3, COMPLEMENT C 03, C3 and PZP-Like Alpha-2-Macroglobulin Domain-Containing Protein 1, Complement C3 [Chemical/Ingredient], c3 complement component, complement component c3, complement c3, c3 complement, complement 3, Complement component 3 (procedure), C3(H20), Complement component C3, C3 - Complement component 3, C3(H20) (substance), Complement component C3 (substance), Complement component C3, NOS, Complement 3, C3, Complement Component 3, C3 Complement, C3, Complement, Complement C3, Complement, C3, Component 3, Complement
Swedish Komplement 3
Czech komplement C3, komplement 3
Finnish Komplementti C3
Russian KOMPLEMENT, KOMPONENT 3, KOMPONENT 3 KOMPLEMENTA, KOMPLEMENT C3, KOMPLEMENT 3, C3 KOMPLEMENTA, KOMPLEMENTA KOMPONENT 3, C3, C3 КОМПЛЕМЕНТА, КОМПЛЕМЕНТ 3, КОМПЛЕМЕНТА КОМПОНЕНТ 3, КОМПЛЕМЕНТ, КОМПОНЕНТ 3, КОМПОНЕНТ 3 КОМПЛЕМЕНТА, КОМПЛЕМЕНТ C3
Japanese 補体3, 補体C3, 補体第3成分
Italian Componente del complemento 3, Frazione del complemento 3
German KOMPLEMENT A 03, Komplement 3
French Protéine C3 du complément, Complément C3, Facteur C3 du complément, Composant C3 du complément, Fraction C3 du complément
Croatian KOMPLEMENT C3, KOMPONENTA KOMPLEMENTA 3
Polish Składnik C3, C3, Komplement 3, Dopełniacz C3
Spanish C3 (H20) (sustancia), C3 (H20), componente C3 del complemento (sustancia), componente C3 del complemento, Complemento C3
Portuguese Complemento C3

Ontology: Complement component C4 (C0009516)

Definition (NCI) Complement component-4 (1744 aa, ~193 kDa) is part of the complement cascade, which mediates the innate immune response to infection. The full length protein is a precursor that can is secreted as a trimeric molecule containing an alpha, beta and gamma chain. When the complement cascade is initiated, the protein is cleaved. This proteolysis releases both the alpha chain, C4 anaphylatoxin, which stimulates inflammation, and a dimer of the beta and gamma chains, which mediates the interaction between the antigen-antibody complex and other complement components.
Definition (MSH) A glycoprotein that is important in the activation of CLASSICAL COMPLEMENT PATHWAY. C4 is cleaved by the activated COMPLEMENT C1S into COMPLEMENT C4A and COMPLEMENT C4B.
Concepts Amino Acid, Peptide, or Protein (T116) , Immunologic Factor (T129)
MSH D003181
SnomedCT 143318005, 65044008, 165931000, 300899005
LNC LP16371-4, MTHU005208
Swedish Komplement 4
English COMPLEMENT C 04, C4, Complement Component-4, Complement C4 [Chemical/Ingredient], complement component c4, complement component 4, complement 4, complement c4, Complement component 4 (procedure), Complement component C4 (substance), C4 - Complement component 4, Complement component 4, Complement-fourth component-C4, Complement component 4 (substance), Complement component C4, Complement component C4, NOS, Complement component C4 (substance) [Ambiguous], Complement 4, C4 Complement Component, C4 Complement, Complement C4, Complement Component 4, Complement Component, C4, Complement, C4, Component 4, Complement, Component, C4 Complement, C4, Complement
Czech komplement C4, komplement 4
Finnish Komplementti C4
Russian KOMPLEMENT 4, KOMPONENT 4 KOMPLEMENTA, C4 KOMPLEMENTA, KOMPLEMENT, KOMPONENT 4, KOMPLEMENTA KOMPONENT 4, KOMPLEMENT C4, C4, C4 КОМПЛЕМЕНТА, КОМПЛЕМЕНТ 4, КОМПЛЕМЕНТА КОМПОНЕНТ 4, КОМПЛЕМЕНТ, КОМПОНЕНТ 4, КОМПОНЕНТ 4 КОМПЛЕМЕНТА, КОМПЛЕМЕНТ C4
Japanese β1E-グロブリン, 補体第4成分, 補体4, C4補体成分蛋白質, 補体C4
Italian Componente del complemento C4, Componente del complemento 4, Frazione del complemento 4
German KOMPLEMENT A 04, Komplement 4
Croatian KOMPONENTA KOMPLEMENTA 4, KOMPLEMENT C4
Polish Dopełniacz C4, C4, Składnik C4, Komplement 4
Spanish componente C4 del complemento, componente C4 del complemento (sustancia), C4 - componente 4 del complemento, componente 4 del complemento (sustancia), componente 4 del complemento, componente C4 del complemento (concepto no activo), cuarto componente del complemento, Complemento C4
French Complément C4, Facteur C4 du complément, Composant C4 du complément, Fraction C4 du complément
Portuguese Complemento C4

Ontology: Complement Activation (C0009528)

Definition (GO) Any process involved in the activation of any of the steps of the complement cascade, which allows for the direct killing of microbes, the disposal of immune complexes, and the regulation of other immune processes; the initial steps of complement activation involve one of three pathways, the classical pathway, the alternative pathway, and the lectin pathway, all of which lead to the terminal complement pathway. [GO_REF:0000022, GOC:add, GOC:mtg_15nov05, ISBN:0781735149]
Definition (NCI) Any physiologic process in which a protease directs the cleavage of complement components C4, C2, or factor B which then form the C3 and C5 convertases for the classical and lectin pathways, respectively. This process is involved in direct lysis of target cells, immune adherence and phagocytosis of pathogens, and recruitment and activation of immunocompetent cells.
Definition (CSP) factors which act in the complement sequence to activate, modulate or prevent the progression of the reaction.
Definition (MSH) The sequential activation of serum COMPLEMENT PROTEINS to create the COMPLEMENT MEMBRANE ATTACK COMPLEX. Factors initiating complement activation include ANTIGEN-ANTIBODY COMPLEXES, microbial ANTIGENS, or cell surface POLYSACCHARIDES.
Concepts Molecular Function (T044)
MSH D003167
English Activation, Complement, Activations, Complement, Complement Activations, complement response, complement activation, activation complement, Complement Activation, complement cascade, Complement activation, complement pathway regulation
Swedish Komplementaktivering
Czech komplement - aktivace
Finnish Komplementtiaktivaatio
French Activation du complément
Russian KOMPLEMENTA AKTIVATSIIA, КОМПЛЕМЕНТА АКТИВАЦИЯ
Croatian KOMPLEMENT, AKTIVACIJA
Polish Aktywacja komplementu, Aktywacja dopełniacza
Norwegian Komplementaktivering
German Komplementaktivierung
Italian Attivazione del complemento
Dutch Complementactivatie, Complementactivering, Complementcascade
Portuguese Ativação do Complemento
Spanish Activación de Complemento

Ontology: Complement Pathway, Alternative (C0009546)

Definition (GO) Any process involved in the activation of any of the steps of the alternative pathway of the complement cascade which allows for the direct killing of microbes and the regulation of other immune processes. [GOC:add, ISBN:0781735149]
Definition (NCI_BioC) The complement system of plasma proteins is an important part of the immune system that forms a cascade of factors that lyses foreign cells. There are two branches of the complement system, the classical pathway that is initiated by antibody-antigen complexes on a cell and the alternative pathway that is antibody independent. The ultimate result in either pathway is the creation of the membrane attack complex, a large pore in the cell membrane that results in cell lysis. The alternative pathway starts with the spontaneous conversion of C3 to an active protease. C3 contains a thioester group that is spontaneously hydrolyzed at a slow rate to create C3(H2O). From there, binding of factor B (Fb) and activation by factor D (Fd) cleaves factor B to create the active protease C3 convertase (AP convertase). This enzyme cleaves C3 to form C3b, which can go on to form a C5 activating convertase. At this point the alternative pathway proceeds in the same manner as the classical pathway, recruiting additional complement factors (C6, C7, C8 and C9) to ultimately form the membrane attack complex and lyse the associated cell. One question about the alternative pathway is how the spontaneous activation of C3 in plasma leads to the lysis of specific cells in the absence of antibody on the cell surface. Active C3b binds to the cell surface, particularly to complement activators like cell wall components and lipopolysaccharide. A constant low level of spontaneous C3b formation ensures that C3b can bind to invading cells and trigger the rest of the alternative complement pathway to lyse the cells even in the absence of an antibody response. The constant low level of C3b activation and potential activation of the alternative pathway is kept in check by a natural damper, factor H and factor I. Factors H and I in plasma inactivate C3b enzyme in solution. Factors H and I cannot inactivate C3b on the cell surface due to protection by properdin, ensuring that the alternative pathway is primarily inactive in plasma and specifically activated on the surface of invading.
Definition (CSP) complement activation sequence initiated by the activation of complement factor C3, which is triggered by the interaction of microbial polysaccharides and properdin without participation of an antigen-antibody reaction.
Definition (MSH) Complement activation initiated by the interaction of microbial ANTIGENS with COMPLEMENT C3B. When COMPLEMENT FACTOR B binds to the membrane-bound C3b, COMPLEMENT FACTOR D cleaves it to form alternative C3 CONVERTASE (C3BBB) which, stabilized by COMPLEMENT FACTOR P, is able to cleave multiple COMPLEMENT C3 to form alternative C5 CONVERTASE (C3BBB3B) leading to cleavage of COMPLEMENT C5 and the assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.
Concepts Molecular Function (T044)
MSH D003170
SnomedCT 86091003
English Alternative Complement Pathway, Complement Pathway, Alternative, Properdin Pathway, complement activation, alternative pathway, Complement activation alternative pathway, function, complement cascade, alternative pathway, Complement activation alternative pathway, function (observable entity), Complement activation alternative pathway, alternative complement pathway, Complement activation alternative pathway, NOS, Complement activation alternative pathway (function), Alternative Complement Activation Pathway, Complement Activation Pathway, Alternative
Spanish Vía Properdina, Vía Alternativa del Complemento, Vía Alternativa de Activación del Complemento, Vía de la Properdina, vía alternativa de activación del complemento (entidad observable), vía alternativa de activación del complemento (función), vía alternativa de activación del complemento
Swedish Komplementaktivering, alternativ
Czech komplement - alternativní dráha
Finnish Komplementin oikotieaktivaatio
French Voie alterne d'activation du complément, Voie de la properdine, Voie alterne du complément
Italian Attivazione della properdina, Attivazione alternativa del complemento
Russian AL'TERNATIVNYI PUT' AKTIVATSII KOMPLEMENTA, PROPERDINOVYI PUT', KOMPLEMENTA AKTIVATSIIA, AL'TERNATIVNYI PUT', АЛЬТЕРНАТИВНЫЙ ПУТЬ АКТИВАЦИИ КОМПЛЕМЕНТА, КОМПЛЕМЕНТА АКТИВАЦИЯ, АЛЬТЕРНАТИВНЫЙ ПУТЬ, ПРОПЕРДИНОВЫЙ ПУТЬ
Polish Alternatywna droga aktywacji dopełniacza, Droga properdynowa, Aktywacja dopełniacza alternatywna
Japanese 副経路(補体活性化), 補体活性化第2経路, プロペルジン経路, 補体副経路, 補体活性化副経路, 補体活性化第二経路, 副経路-補体活性化
Norwegian Alternativ komplementaktiveringsmekanisme, Properdinmediert komplementaktiveringsmekanisme
Portuguese Via Alternativa de Ativação do Complemento, Via da Properdina, Via Alternativa do Complemento, Via Properdina
German Alternative Komplementaktivierung, Komplementaktivierung, alternative, Properdininduzierte Aktivierung
Dutch Complementactivering, via alternatieve route

Ontology: Complement Pathway, Classical (C0009547)

Definition (NCI_BioC) The complement system is part of the defense against invading cells and is composed of about twenty different proteins found in the plasma. When activated, complement proteins form a pathway of proteolytic reactions that culminates in the lysis of foreign cells. The complement system also stimulates phagocytosis of foreign cells and an inflammatory response. There are two different complement systems, the classical complement pathway initiated by antibody complexes on the cell surface, and an alternative complement pathway that is initiated without antibodies. The complement system proteins are named with a capital C followed by a number. A small letter after the number indicates that the protein is a smaller protein resulting from the cleavage of a larger precursor by a protease. In the classical pathway, the first step is the initiation of the pathway triggered by recognition by complement factor C1 of antigen-antibody complexes on the cell surface. When C1 complex interacts with aggregates of IgG with antigen on a cell's surface, two C1-associated proteases, C1r and C1s, are activated. Other factors like lipopolysaccharide also activate C1s. Once C1s is activated, it cleaves C4 to form C4b that then binds to the cell membrane of the cell being attacked. The proteolytic complement cascade is then amplified on the cell membrane through sequential cleavage of complement factors and recruitment of new factors until a cell surface complex containing C5b, C6, C7, and C8 is formed. The addition of a multiple C9 proteins creates the membrane attack complex results in a large pore that spans the membrane of the cell being attacked, allowing ions to flow freely between the cellular interior and exterior. Ions flow out, but large molecules stay in, causing water to flood into the cell and ultimately burst the cell from osmotic pressure.
Definition (CSP) sequential activation of complement, initiated by antigen-antibody complex and the binding of complement factor C1q to the Fc region of the antibody.
Definition (MSH) Complement activation initiated by the binding of COMPLEMENT C1 to ANTIGEN-ANTIBODY COMPLEXES at the COMPLEMENT C1Q subunit. This leads to the sequential activation of COMPLEMENT C1R and COMPLEMENT C1S subunits. Activated C1s cleaves COMPLEMENT C4 and COMPLEMENT C2 forming the membrane-bound classical C3 CONVERTASE (C4B2A) and the subsequent C5 CONVERTASE (C4B2A3B) leading to cleavage of COMPLEMENT C5 and the assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.
Concepts Molecular Function (T044)
MSH D003171
English Classical Complement Pathway, Complement Pathway, Classical, classical complement pathway, Classical Complement Activation Pathway, Complement Activation Pathway, Classical
Spanish Vía Clásica del Complemento, Vía Clásica de Activación del Complemento, Vía Clásica del Sistema Complemento
Swedish Komplementaktivering, klassisk
Czech komplement - klasická dráha
Finnish Komplementin klassinen aktivaatiotie
French Voie classique du complément, Voie classique d'activation du complément
Russian KLASSICHESKII PUT' AKTIVATSII KOMPLEMENTA, KOMPLEMENTA AKTIVATSIIA, KLASSICHESKII PUT', КЛАССИЧЕСКИЙ ПУТЬ АКТИВАЦИИ КОМПЛЕМЕНТА, КОМПЛЕМЕНТА АКТИВАЦИЯ, КЛАССИЧЕСКИЙ ПУТЬ
Polish Klasyczna droga aktywacji dopełniacza, Aktywacja dopełniacza klasyczna
Japanese 補体活性化第1経路, 古典経路(補体活性化), 補体古典経路, 補体活性化古典経路, 補体活性化第一経路
Norwegian Klassisk komplementaktiveringsmekanisme
Portuguese Via Clássica de Ativação do Complemento, Via Clássica do Sistema Complemento, Via Clássica do Complemento
German Klassische Komplementaktivierung, Komplementaktivierung, klassische
Italian Attivazione sequenziale del complemento
Dutch Complementactivering, klassieke, Klassieke complementactivering

Ontology: Disorder of complement (C0272240)

Concepts Disease or Syndrome (T047)
SnomedCT 24419001
English Disorder of complement (disorder), Disorder of complement, complement system; disorder, disorder; complement system, Disorder of complement, NOS
Dutch complementsysteem; stoornis, stoornis; complementsysteem
Spanish defectos del sistema del complemento (trastorno), defectos del sistema del complemento, trastorno del complemento

Ontology: Complement abnormality (C0272241)

Concepts Disease or Syndrome (T047)
SnomedCT 18827005
English complement abnormality (diagnosis), Complement abnormality (disorder), Complement abnormality, Complement abnormality, NOS
Spanish anomalía del sistema del complemento (trastorno), anomalía del sistema del complemento

Ontology: Complement deficiency disease (C0272242)

Definition (NCI) A broad classification for rare genetic disorders with mostly autosomal recessive patterns of inheritance. They are caused by the ineffective or decreased biosynthesis of complement components. Complement deficiencies may also be acquired acutely post-infection or chronically from co-morbid autoimmune disorders. If complement components are adequately synthesized, their rapid depletion may result in functional deficiencies. Clinical signs of inherited deficiencies present within the first decade of life and are consistent with the signs of recurrent systemic infection or immune complex disease. Complement deficiencies decrease the effectiveness of the humoral immune response. Of all the complement deficiencies, C3 deficiency is associated with the poorest prognosis since it presents at an early age, when susceptibility to recurrent infection is great. Deficiencies of C3 and of the classical activating pathway components: C1, C4, C2 also predispose to immune complex disease.
Definition (CSP) rare disease where complement protein(s) are absent or in diminished amount relative to the normal requirement of an organism; associated with autoimmune disease or increased susceptibility to infections, problems encountered depend on which pathway is affected.
Concepts Disease or Syndrome (T047)
ICD10 D84.1 , D80-D89
SnomedCT 191014008, 24743004
English Complement deficiency, Defects in complement system, complement deficiency, deficiency complement, complement deficiencies, defects in the complement system, defects in the complement system (diagnosis), defects in complement system, Complement deficiency (disorder), complement deficiency disease (diagnosis), Complement deficiency disease, Defects in the complement system, Complement deficiency disease (disorder), complement system; defect, defect; complement system, Complement deficiency disease, NOS, Complement Deficiency
German Defekte im Komplementsystem
Korean 보체계통의 결손
Dutch complementsysteem; defect, defect; complementsysteem, Stoornissen in complementsysteem
Spanish enfermedad de deficiencia del sistema del complemento (trastorno), enfermedad de deficiencia del sistema del complemento

Ontology: Complement Pathway, Mannose-Binding Lectin (C1138407)

Definition (MSH) Complement activation triggered by the interaction of microbial POLYSACCHARIDES with serum MANNOSE-BINDING LECTIN resulting in the activation of MANNOSE-BINDING PROTEIN-ASSOCIATED SERINE PROTEASES. As in the classical pathway, MASPs cleave COMPLEMENT C4 and COMPLEMENT C2 to form C3 CONVERTASE (C4B2A) and the subsequent C5 CONVERTASE (C4B2A3B) leading to cleavage of COMPLEMENT C5 and assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.
Concepts Molecular Function (T044)
MSH D037582
Swedish Komplementaktivering, mannosbindande lektin
Czech lektinová dráha aktivace komplementu
Finnish Mannoosia sitovan lektiinin komplementtiaktivaatio
French Voie lectine liant le mannose, Voie d'activation par la lectine liant le mannose, Voie de la MBL, Voie des lectines liant le mannose, Voie des lectines, Voie de la lectine
Italian Attivazione del complemento della lectina, Attivazione del complemento della lectina legante il mannano, Attivazione della lectina legante il mannano (attivazione del complemento), Attivazione del complemento della lectina legante il mannosio
Russian MANNOZA-SVIAZYVAIUSHCHII LEKTIN, KOMPLEMENTA AKTIVATSII PUT', MANNAN-SVIAZYVAIUSHCHII LEKTIN, KOMPLEMENTA AKTIVATSII PUT', KOMPLEMENTA AKTIVATSIIA, MANNOZA-SVIAZYVAIUSHCHII LEKTIN, KOMPLEMENTA AKTIVATSII PUT', MANNOZA-SVIAZYVAIUSHCHII LEKTIN, КОМПЛЕМЕНТА АКТИВАЦИИ ПУТЬ, МАННОЗА-СВЯЗЫВАЮЩИЙ ЛЕКТИН, КОМПЛЕМЕНТА АКТИВАЦИЯ, МАННОЗА-СВЯЗЫВАЮЩИЙ ЛЕКТИН, МАННАН-СВЯЗЫВАЮЩИЙ ЛЕКТИН, КОМПЛЕМЕНТА АКТИВАЦИИ ПУТЬ, МАННОЗА-СВЯЗЫВАЮЩИЙ ЛЕКТИН, КОМПЛЕМЕНТА АКТИВАЦИИ ПУТЬ
Japanese マンナン結合レクチン補体経路, 補体経路-マンノース結合レクチン, マンノース結合レクチン補体経路
Spanish Vía del Complemento de la Lectina de Unión al Manano, Vía del Complemento de la Lectina, Lectina de Unión a Manosa de la Vía del Complemento, Vía de la Lectina de Unión a Manosa de Activación del Complemento, Vía de la Lectina de Unión a Manosa de la Vía de Activación del Sistema Complemento, Vía de la Lectina de Unión a Manosa del Sistema Complemento, Vía del Complemento de la Lectina de Unión a Manano, Vía de la Lectina de Activación del Complemento
Portuguese Via do Complemento da Lectina Ligante de Manana, Lectina Ligante de Manose da Via de Ativação do Complemento, Lectina Ligante de Manose da Via do Complemento, Via do Complemento da Lectina Ligante de Manose, Via da Lectina do Complemento, Via da Lectina Ligante de Manose da Via de Ativação do Sistema Complemento, Via do Complemento da Lectina de Ligação a Manana, Lectina Ligante de Manose do Sistema Complemento, Via da Lectina Ligante de Manose do Complemento, Via da Lectina do Sistema Complemento, Via da Lectina Ligante de Manose do Sistema Complemento, Lectina de Ligação a Manose da Via do Complemento
Polish Szlak dopełniacza lektyny wiążącej mannozę
Norwegian Mannosebindende lektinkomplementaktiveringsmekanisme
English Complement Pathway, Mannose Binding Lectin, Complement Pathway, Mannose-Binding Lectin, Lectin Pathway, Mannan-Binding (Complement Activation), Lectin Pathways, Mannan-Binding (Complement Activation), Mannan Binding Lectin Complement Pathway, Mannan Binding Lectin Pathway (Complement Activation), Mannan-Binding Lectin Complement Pathway, Mannan-Binding Lectin Pathway (Complement Activation), Mannan-Binding Lectin Pathways (Complement Activation), Mannose Binding Lectin Complement Pathway, Mannose-Binding Lectin Complement Pathway, Pathway, Mannan-Binding Lectin (Complement Activation), Pathways, Mannan-Binding Lectin (Complement Activation), Lectin Complement Pathway, Lectin-Complement Pathways, Lectin-Complement Pathway, Pathway, Lectin-Complement, Pathways, Lectin-Complement
German Komplement-Aktivierungsweg, Mannose-bindendes Lectin, Mannose-bindendes Lectin, Komplement-Aktivierungsweg, Mannose-bindendes Lectin
Dutch Complementroute, mannosebindend lectine-, Mannose-bindend lectinecomplementroute

Ontology: complement pathway (C1305430)

Definition (NCI_BioC) The complement pathway consists of a series of over thirty proteins in plasma that are part of the immune response. Activation of the complement system lyses bacterial cells, forms chemotactic peptides (C3a and C5a) attracting immune cells, and increases phagocytotic clearance of infecting cells. Complement can also increase the permeability of vascular walls and cause inflammation. Most complement proteins exist in plasma as inactive precursors that cleave and activate each other in a proteolytic cascade in response to three different mechanisms by which the complement system is activated, the classical pathway, the alternative pathway and the lectin-induced pathway. These three systems are distinct in the initiation of the proteolytic cascade but share most of their components and all three converge in the creation of a C3 convertase that cleaves the C3 complement protein, leading ultimately to the formation of the membrane attack complex, MAC, a pore causing lysis of cells. The classical pathway is activated by the recognition of foreign cells by antibodies bound to the surface of the cells. The alternative and lectin-induced pathways are both antibody independent. Proteolysis is triggered in the alternative pathway by the spontaneous activation of C3 convertase from C3 and is triggered in the lectin-induced pathway by the recognition of carbohydrates on the bacterial cell surface by mannan-binding protein, Mbp. In addition to providing a key part of the response to bacterial infection, the complement system can be involved in the response to fungi, viruses and protists. While activation of the complement system is a key part of the immune system, it must also be kept in check to prevent inappropriate or exaggerated responses. Twelve different proteins have been identified that inhibit complement activation to control the system, including Factor H, Factor I and C1 inhibitor. Deficiencies in components of the complement system have been identified in humans that cause a variety of immune related disorders. C3 deficiency is associated with recurrent bacterial infections, while a lack of C2 can cause antibody-antigen complexes to accumulate and cause the autoimmune disorder systemic lupus erythematosus. People lacking C1 inhibitor have also been identified and found to be prone to uncontrolled complement activation and dangerous swelling through production of C3a and C5a anaphylatoxins.
Definition (CSP) classical complement pathway is the sequential activation of complement, initiated by antigen-antibody complex and the binding of complement factor C1q to the Fc region of the antibody; alternative complement pathway is the complement activation sequence initiated by the activation of complement factor C3, which is triggered by the interaction of microbial polysaccharides and properdin without participation of an antigen-antibody reaction.
Concepts Molecular Function (T044)
English complement pathways, complement pathway, Complement Pathway

Ontology: CH50 Measurement (C3540691)

Definition (NCI_CDISC) A measurement of the complement required to lyse 50 percent of red blood cells in a biological specimen.
Definition (NCI) A measurement of the complement required to lyse 50 percent of red blood cells in a biological specimen.
Concepts Laboratory Procedure (T059)
English CH50 Measurement, Complement CH50, CH50, Total Hemolytic Complement