Term
| Complement proteins are synthesized where? |
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Definition
|
|
Term
| What is common b/w the alternative and classical complement pathways? |
|
Definition
| Both pathways generate the "C3b" fragment |
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|
Term
| What complement pathway leads to osmotic lysis of cells or microbes? |
|
Definition
| Terminal pathway of complement cascade ; this is done by MAC complex |
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Term
| Complement component C3b can bind to what in circulation ? |
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Definition
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|
Term
| How many base complement proteins are there? |
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Definition
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Term
| When is classical complement pathway initiated ? |
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Definition
| Only when IgM or IgG Abs bind to antigen or when antigen/antibody complex (immune complex is formed) |
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Term
| In an immune complex what is bound to Ab and what is bound to complement ? |
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Definition
Antigen is bound via Fab region of Ab
Fc region binds to complement protein |
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|
Term
| C1 is composed of what 3 components? |
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Definition
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|
Term
| Why is IgM more efficient at complement activation than IgG ? |
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Definition
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Term
| What is the classical complement pathway C3 convertase ? |
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Definition
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Term
| What does the C3 convertas complex in classical complement pathway do ? |
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Definition
| It cleaves C3 to C3a and C3b |
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|
Term
| What is hallmark of classical complement pathway activation ? |
|
Definition
| Formation of C3 convertase |
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|
Term
| What is required for C5 convertase formation in classical complement pathway ? |
|
Definition
|
|
Term
| What is the C5 convertase and what does it do? |
|
Definition
| C4b2a3b ; it cleaves C5 into C5a and C5b |
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Term
|
Definition
Are anaphylatoxins
Bind to mast cells and basophils, induce degranulation, and release of histamine and other inflammatory mediators |
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|
Term
| Function of histamine is ? |
|
Definition
| Increases vascular permeability |
|
|
Term
| C5a is chemotactic for what? |
|
Definition
|
|
Term
| When is anaphyhlatoxin C4a generated ? |
|
Definition
| Only following activation of the classical complement pathway |
|
|
Term
| What are the many function of C3b ? |
|
Definition
It serves as an opsonin on microbial surfaces
Facilitates elimination of immune complexes
Amplifies complement activity
is required for formation of C5 convertases in both alternative and complement pathways |
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|
Term
| MAC is formed by what complement proteins ? |
|
Definition
|
|
Term
|
Definition
| Is a weak kinin that increases vascular permeability , and so contributes to genesis of inflammation |
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|
Term
| What is the C3 convertase in alternative pathway ? |
|
Definition
|
|
Term
| What is the C5 convertase in terminal pathway ? |
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Definition
|
|
Term
| Components of the Terminal / Common Complement pathway ? |
|
Definition
|
|
Term
| What is the initiator molecule for generation of MAC in the terminal complement pathway ? |
|
Definition
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|
Term
| What are the complement proteins in the alternative complement pathway ? |
|
Definition
| C3b, Factor B, Factor D, Properdin, C3, C5 |
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|
Term
| How is alternative pathway activated ? |
|
Definition
| Invasion of an infectious agent causes spontaneous creation of C3b (or "tickover") |
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|
Term
| What happens to spontaneously generated C3b in absence of microbial infection ? |
|
Definition
| C3b is rapidly inactivated either by interaction with water or complement regulatory proteins |
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|
Term
|
Definition
| Causes hydrolysis of Factor B to Ba and Bb |
|
|
Term
| What is the alternative pathway C3 convertase ? |
|
Definition
|
|
Term
| What stabilizes the C3 convertase in the alternative complement pathway ? |
|
Definition
|
|
Term
| What is the alternative pathway C5 convertase ? |
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Definition
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|
Term
| C1 INH (C1 esterase inhibitor) does what ? |
|
Definition
| Inhibits C1 and the protease kallikrein |
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|
Term
| Kallikrein links what two things ? |
|
Definition
| The complement and intrinsic coagulation pathways |
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|
Term
| What does DAF (Decay Accelerating Factor) do ? |
|
Definition
| Blocks formation of alternative and classical pathway C3 convertases, by binding to C4b and C3b |
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|
Term
| What does C4bp (C4 binding protein) do ? |
|
Definition
Is a cofactor for Factor I
Binds to C4b preventing its attachment to cells |
|
|
Term
|
Definition
| Factor I cleaves C4b to its inactive form C4bi |
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|
Term
| What does AI (Anaphylatosin inhibitor) do ? |
|
Definition
| Binds to C3a, C4a, and C5a and inhibits their binding to receptors on mast cells and basophils |
|
|
Term
| What are the classical complement pathway regulators ? |
|
Definition
C ACFD
C1 INH
AI
C4bp
Factor I
DAF |
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|
Term
| What are the alternative complement pathway regulatory proteins ? |
|
Definition
FFAD
Factor H
Factor I
AI
DAF |
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|
Term
|
Definition
| Inactivates C3b/C4b via CR1 |
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|
Term
| What does Factor H do in alternative pathway? |
|
Definition
| Competitively binds with C3b, inducing dissociation of this convertase |
|
|
Term
| What are the 3 MAC inhibitors ? |
|
Definition
HRF (homologous restriction factor)
S-protein / vitronectin
CD59 / HRF20 |
|
|
Term
| What does kallikrein do ? |
|
Definition
| In presence of cofactor kininogen, Factor 12 is converted to Factor 12a |
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|
Term
| Do Factor 12a and kallikrein reciprocally activated each other ? |
|
Definition
|
|
Term
| Proteolytic hydrolysis of kininogen does what ? |
|
Definition
| Generates kininogen(a) and bradykinin (a vasodilator that increases vascular permeability). |
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|
Term
| What is the complement ligand fragment for CR1 receptor ? |
|
Definition
|
|
Term
| CR1 is found on what cells ? |
|
Definition
| Phagocytes and Erythrocytes |
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|
Term
| CR1 binds with C3b or C4b to do what ? |
|
Definition
Opsonin mediated recognition of antigen
Clearance of circulating immune complexes |
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|
Term
| CR2 receptor binds with what complement ligand fragment ? |
|
Definition
|
|
Term
| CR2 receptor is found on what cell type ? |
|
Definition
|
|
Term
| CR2 binding with C3bi occurs in what mode of infection ? |
|
Definition
| Mode of Epstein Barr virus infection |
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|
Term
| CH50 complement test is for what ? |
|
Definition
| Classical complement pathway |
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|
Term
| If CH50 test is not available, then what is done ? |
|
Definition
|
|
Term
| Does CH50 test detect deficiencies in specific complement components ? |
|
Definition
| No, it measures total classic complement pathway activity |
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