Complement Flashcards
What are the two antibodies that are most potent in activation of complement system?
IgM, IgG
Components of complement are synthesized in the liver. They reside in all tissue fluid except?
CSF( cerebral spinal fluid)
Urine
What are the three methods of activation of the complement system?
Spontaneously
Antigen antibody complex
Bacterial products
What are functions of C1 inhibitor, factor I, factor s, factor H, CD59.
Inhibits the complement system
How is the classical pathway activated?
Antigen antibody complex
Write down The C1 complex of the classical and mannan binding lecting pathway
C1qr2s2
C2 is broken down to C2a and C2b. Which of the two is used in the complex reaction?
C2a
Write down the components of C3 convertase of the classical pathway.
C4b2a
Function of C3 convertase?
Breaks down C3 into C3a and C3b
Write down the components of C5 convertase of the classical pathway.
C4b2a3b
Function of C5 convertase?
Breaks C5 to C5a and C5b
Components of the membrane attack complex
C5b678 and poly 9
Which complement pathway is activated spontaneously?
Alternative pathway
Which complement components are bypassed in the alternative pathway?
C1, C4 and C2
Which component of the alternative pathway breaks down spontaneously?
C3 to C3a and C3b
Which factor breaks down factor B?
Factor D
Write down C 3 convertase of the alternative pathway
C3bBb
What is properdin? When is it formed?
A component that stabilizes the C3 convertase.
It’s formed during the formation of C3 convertase
What does the C3 convertase do in the alternative pathway?
Breaks down C3 into C3a and C3b
Write down C5 convertase of the alternative pathway?
C3bBb3b
Is the properdin system involved in the classical pathway? T or F
F
Which component of complement produces a kinin?
Function of a kinin?
Cleavage of C2a
Function: increase vascular permeability
Most important function of MAC(membrane attack complex)?
Protects against Neisseria
What are chemotactics?give examples.
Complement components that attract neutrophils and macrophages
Examples: C5a and C3a
Examples of anaphylaxins?
C3a C5a C4a. They cause degranulation of mast cells to produce inflammatory substances(eg histamin)
What initiates the formation of MAC
C5b by binding C6
What binds Fc portion of the antibodies igM and IgG
C1q
What is the the order of complement participation.
C4b c2a C3b C5b C6 C7 C8 C9
Kidneys transplanted from pigs to primates dies within minutes. Which complement pathway mediates this?
Alternative pathway
Which surface is spontaneous activation of C3 promoted?
Pig cells
List initiators of alternative pathways both pathogens and nonpathogens
Pathogens
Fungal and yeast cell.walls
Viruses and virus infected cells
Tumour cells. eg Raji
Parasites(trypanosomes)
Nonpathogens
Pure carbohydrates
Coverage venom factor
Human igG. IgA. IgE.
Rabbit and guine pig igG
Which pathway deals with non-specific innate immunity?
Alternative pathway
Which pathway deals with specific acquired immunity?
Classical pathway
Which pathways I similar to classical pathway?
Lectin pathway
Which complement components do complement receptors bind.
MBL, C1, and activated C4 and C3
Which receptor induces degradation of mast cells and basophils
C4a, C3a, C5a receptor
Which receptor blocks formation of C3 convertase aasnd binds immune complex to cells
CR1
Major lingand-C3b, C4b
Which receptor binds Epstein-barr virus
CR2
What does cleavage of C3dg by serum proteases generate
C3d and C3g
What activates the final part of the cascade of complement componentd
C3
What do the following deficiencies lead to
1. C2 and C4
2. C3 and factor D
3. Deficiency of C5-C9
4. Deficiency of regulatory proteins
Lupus erythematosus
Pyogenic bacterial infection
Neisseria
Cell lysis and inflammations
What executes cytolysis
MAC
Opsonization
Anaphylaxon
Activate phagocytosis and neutrophils
- C3b
- C3a,4a,5a
- C5a
Recognition unit of classical
C1q
Ab independent pathways
Alternative
Lectin
All three pathway converge at point of
Cleavage of C3
Ions needed for complement cascade
Can, mg
Which part of immunoglobulin structure is involved in activation of complement via classical
Fc region
What facilitates the binding of immune complex to several surfaces (erythrocytes) and enhance removal of liver and spleen?
C3b
What is C3 deficiency associated with?
Immon-complex disease and susceptibility to recurrent infections
Patients who produce less antibody and are more susceptible to pyogenic infection, are deficient in what?
C3b
