Week 6 Immunology

Front 1

Classical pathway [LO]

Back 1

[LO]

Front 2

Lectin pathway [LO]

Back 2

[LO]

Front 3

alternate complement pathway [LO]

Back 3

[LO]

Front 4

Role of constituent proteins [LO]

Back 4

[LO]

Front 5

role of the complement system in protecting from and causing disease. [LO]

Back 5

[LO]

Front 6

what is the role of the C3ac5a split product?

Back 6

Aggregation of platelets.
Chemotactic for leukocytes (C5a >>>> C3a).
Acts on mast cells --> histamine --> vasodilation --> ↑↑ vascular permeability.

Front 7

What is the role of the split product C3a & C5a

Back 7

Are rapidly degraded by serum carboxypeptidase

Front 8

What is the role of the split product C3b

Back 8

Opsonisation (process whereby opsonins make an invading microorganism more susceptible to phagocytosis).
Bystander lysis.

Front 9

What is the role of the split product C5b

Back 9

Opsonisation (process whereby opsonins make an invading microorganism more susceptible to phagocytosis).
Bystander lysis.

Front 10

What is the role of the split product C1 INH

Back 10

Removes C1r and C1s from C1q
Binds to C1rC1s blocking activity

Front 11

What is the role of the split product Factor 1

Back 11

Cleaves C3b, C4b into inactive forms

Front 12

What is the role of the split product Factor H

Back 12

Inhibits C3bB formation
Disrupts C3bBb complexes
Acts with Factor I – ↑ decay of C3b --> C3c + C3d

Front 13

What is the role of the regulatory protein CR1

Back 13

Binds C4b, displacing C2b.
Binds C3b, displacing Bb.
Cofactor for Factor I (FI; which regulates complement activation by cleaving cell-bound or fluid phase C3b and C4b.

Front 14

What is the role of the regulatory protein DAF

Back 14

Same function as CR1 except it doesn’t at as a cofactor for Factor I.

Front 15

What is the role of the regulatory protein MCP

Back 15

Increases inactivation of C3b and C4b.

Front 16

What is the role of the regulatory protein Vitronectin (S protein)

Back 16

Prevents C5b, C6 and C7 binding to membrane.

Front 17

What is the role of the regulatory protein CD59?

Back 17

Prevents C5b – C7 formation on homologous cells

Front 18

What is the role of the regulatory protein (Thermal instability)?

Back 18

Very short half life (T1/2).

Front 19

What are the AgAb complexes in the Classical pathway?

Back 19

C1q, C1r, C1s, C4, C2

Front 20

What are the mannose binding lectin or ficolin binds carbohydrates on pathogen surfaces?

Back 20

MBL, MASP-2, C4, C2

Front 21

What are the proteins on the pathogen surfaces of the alternative pathway?

Back 21

C3, B factor, D factor

Front 22

What does C3a do?

Back 22

peptide mediator of:
1. inflammation
2. phagocyte recruitment

Front 23

What is the function of C3b

Back 23

1. Binds to complement receptors of phagocytes
2. Opsonisation of pathogens
3. Removal of immune complexes

Front 24

What are the Terminal Complement components?

Back 24

C5b, C6, C7, C8, C9

Front 25

Where does C1q bind?

Back 25

Multiple Fc regions

Front 26

Which Abs does C1q bind?

Back 26

IgM, IgG1, IgG3

Front 27

Where does complement reside?

Back 27

It is confined to the surface on which it is initiated.

Front 28

Describe what C1-INH does

Back 28

Front 29

Describe the actions of the C1 inhibitor

Back 29

Front 30

What removes C1r and C1s

Back 30

Front 31

What can remove MASPs?

Back 31

Front 32

What does the Factor I do?

Back 32

Front 33

What does Factor I have to be bound to be a regulator?

Back 33

CR1 or the Membrane cofactor protein

Front 34

What breaks c3b down to ic3b and C3dg?

Back 34

Factor I

Front 35

What does FI do to both C3b and C4b?

Back 35

C3b --> ic3b and c3dg
C4b --> c4c, c4d

Front 36

What are the serine protease inhibitors in the complement system

Back 36

C1-INH and Factor I

Front 37

What displaces Bb in the alternate complement pathway?

Back 37

Factor H

Front 38

What is C4BP?

Back 38

cofactor for factor I, cleaves c4b to C4d, C4c

Front 39

function of DAF

Back 39

Competes with B for C3b
Splits up C4b2a and c3bBb with CR1
And prevents MAC with CD59

Front 40

Where does DAf reside? What does it to in conjunction with what?

Back 40

on host cells also dissociate C4b2a and C3bBb in conjunction with CR1

Front 41

What prohibits the MaC from forming?

Back 41

CD59 and DAF on host cells prevent binding of C9 in MAC complex

Front 42

What does CD59 do?

Back 42

Front 43

What are the classical pathway deficiencies?

Back 43

C1 deficiency
C2 deficiency
C4 definciency

Front 44

What are the symptoms and prognostics of C1 deficiency?

Back 44

skin and kidney disorders- pts rarely reach adulthood

Front 45

What is the most common classical pathway deficiency?

Back 45

C2 deficiency, has milder effects

Front 46

What is C4 deficiency

Back 46

coded in 2 genes
partial deficiency more common

Front 47

What are deficiencies associated with alternate and lectin pathways?

Back 47

Front 48

What happens if deficient in C1-INH

Back 48

desregulated bradykinin production (Bradykinin is a peptide that causes blood vessels to dilate (enlarge))

Front 49

What causes dysreagulation of bradykinin

Back 49

C1-INH deficiency

Front 50

What causes C1-INH deficiency

Back 50

autosomal dominant hereditary angioedema

Front 51

What is the good news about hereditary angioedema?

Back 51

transient - however life threatening if airways blocked

Front 52

How is hereditary angioedema treated?

Back 52

C1-INH concentrate doses

Front 53

What occurs if a factor H mutation exists

Back 53

Impaired C3 convertase -->
atypical haemolytic uraemic sydrome
endothelial damage --> fibrin depostion
Haemolytic anaemia
thrombocytopenia
renal failure

Front 54

Which deficiency causes the following and why?
atypical haemolytic uraemic sydrome
endothelial damage --> fibrin depostion
Haemolytic anaemia
thrombocytopenia
renal failure

Back 54

Impaired C3 convertase by factor H deficiency - Factor H inhibits Bb and therefore cannot convert to c3a, c3b (positive feedback)

Front 55

What deficiency causes PNH and complement mediated red cell lysis

Back 55

CD59 and DAF

Front 56

What does CD59 and DAF deficiencies cause

Back 56

CD59 - prevent membrane complexes
DAF - usurps Bb for binding with c3b, membrane complexes and prevents c5 convertase when with
- splits c3bBb, c4b2a
Causes paroxymal nocturnal haemoglobinuria and complement mediated red cell lysis

Front 57

When is classical pathway used?

Back 57

Ag Ab complexes

Front 58

When is lectin pathway used?

Back 58

microbes with terminal manose groups or acetylated sugars

Front 59

When is alternative pathway used?

Back 59

bacteria, fungi virus or tumour cells.

Front 60

What deficiencies cause lupus like disease?

Back 60

C1, C2, C4

Front 61

What deficiencies cause severe recurrent bacterial infections?

Back 61

C3
fH
fI
B
D

Front 62

What deficiencies cause neisserial infection?

Back 62

Factor P

Front 63

What causes RECURRENT Neisserial infection?

Back 63

c6, c7, c8, c9

Front 64

What is complement testing performed on?

Back 64

fresh serum

Front 65

Describe classical pathway screen

Back 65

Front 66

Describe Alternative pathway screen

Back 66

Front 67

Describe Opsonisation

Back 67

Front 68

Describe the agents responsible for chemotaxis and inflammation

Back 68

C3a and C5a:
‘anaphylatoxins’

Front 69

What is the c3aR located on?

Back 69

esinophils, basophils more than neutrophils

Front 70

Where is the c5aR found?

Back 70

white cells

Front 71

What does the binding of c3aR or c5aR do?

Back 71

++ adhesive properties of host cells
+++ extravasion
primes phagocytes to excrete enzymes, vasoactive amines and inflammatory cytokines
•  swelling, heat and pain
•  fever and shock
•  C3a and C5a:
‘anaphylatoxins’

Front 72

What does C3b perform?

Back 72

from classical pathway coats and opsonises the aggregated complex

Front 73

What is the role of CR1 and where is it located?

Back 73

CR1 on red cells binds C3b (and C4b) to carry the complex to sites of macrophage residency

Front 74

What primes B cells?

Back 74

Binding of antigen bound to C3 fragments enhances antigen specific B cell selection and maturation

Ag bound to BCR, C3 fragment (C3d) bound to CR2