Complement System p1 (classical pathway)

Question 1

A complex series of more than 30 soluble and cell-bound proteins that interact in a very specific way to enhance host defense mechanism against foreign cells

Answer 1

Complement

Question 2

Is complement a heat-labile or heat-stable substance?

Answer 2

Heat-labile

Question 3

Who gave the term “complement”?

Answer 3

Paul Erlich

Question 4

Who was awarded a Noble Prize for elucidating the nature of complement?

Answer 4

Jules Bordet

Question 5

Effect of complement activation:

Answer 5

Activation of immune system
Opsonization (C3b, C4b, C5b)
Lysis of foreign cells and immune complexes

Question 6

What is the effect of chronic complement activation?

Answer 6

Leads to inflammation and tissue damage

Question 7

Where are acute phase reactants produced?

Answer 7

Hepatocytes

Question 8

The two most common acute phase reactant in the body

Answer 8

C-reactive protein
Serum amyloid A

Question 9

Who signals the production of acute phase reactants in the hepatocytes?

Answer 9

Cytokines

Question 10

What is the response time of the production of acute phase reactants?

Answer 10

12-24 hours

Question 11

Where are most plasma complement protein synthesized?\

Answer 11

Liver

Question 12

All plasma complement protein are synthesized in the liver except:

Answer 12

C1

Question 13

Where is C1 produced?

Answer 13

Epithelial cells and Factor D (made in adipose tissue)

Question 14

Plasma complement protein are released in inactive precursor called:

Answer 14

Zymogens

Question 15

In what ways can the complement system be activated?

Answer 15

Classical pathway
Alternative pathway
Lectin pathway

Question 16

This is an antibody-independent pathway which plays a major role as a natural defense system

Answer 16

Classical pathway

Question 17

Aka properdin system

Answer 17

Alternative pathway

Question 18

Stabilized C3 convertase of the alternative pathway

Answer 18

Properdin

Question 19

This pathway’s major constituent is mannose binding lectin (MBL)

Answer 19

Lectin pathway

Question 20

What triggers the proteins in the classical pathway?

Answer 20

Antigen-antibody combination

Question 21

Where is mannose found?

Answer 21

Cell walls
Outer coating of the bacteria, viruses, and protozoa

Question 22

How many proteins are involved in the classical pathway?

Answer 22

9

Question 23

Which immunoglobulin is the most efficient in the activation of the classical pathway?

Answer 23

IgM

Question 24

Can the IgG activate the classical pathway?

Answer 24

Yes

Question 25

IgGs capable of activating the classical pathway?

Answer 25

IgG 1, 2, 3

Question 26

Most efficient IgG for the complement fixation

Answer 26

IgG 3

Question 27

Meaning of MAC

Answer 27

Membrane Attack Complex

Question 28

What protein is always involved in the recognition stage of the classical pathway?

Answer 28

C1

Question 29

In the classical pathway, after the C1 has been fixed, what proteins are next to be activated?

Answer 29

C4, C2, C3

Question 30

What is the C4, C2, C3 known as?

Answer 30

Activation unit

Question 31

What is the last stage of the classical pathway?

Answer 31

Formation of the MAC

Question 32

What should happen in order to produce the mechanism of lysis?

Answer 32

C5 protein up to C9 should match to its respective complements

Question 33

What is the end product of the classical pathway?

Answer 33

Lysis of the foreign cells

Question 34

What are the subunits that consists the recognition unit in classical pathway?

Answer 34

C1q, C1r, C1s

Question 35

What is the complex of the recognition stage in the classical pathway made up of?

Answer 35

One C1q Two C1r Two C1s

Question 36

Which subunits in the recognition stage of the classical pathway generate enzyme activity to begin the cascade?

Answer 36

C1r, C1s

Question 37

Composed of six strands that form six globular heads with a collagen like tail portion

Answer 37

C1q

Question 38

This protein recognizes the FC region of two adjacent antibody molecules Binds to the Fc portion of the antibody

Answer 38

C1q

Question 39

What should be the conditions for the C1q to initiate the classical pathway?

Answer 39

At least two of the globular heads of C1q must be bound

Question 40

Process of the recognition stage of the classical pathway

Answer 40

Fc region is bonded with C1q Activation of C1r Cleaves the thioester bond of C1s Activates C1s End of recognition stage

Question 41

Where does the binding of the C1q to the FC region occur?

Answer 41

Ch2 region for IgG Ch3 region for IgM

Question 42

What are the two adjacent antibody molecule in the classical pathway?

Answer 42

IgG and IgM

Question 43

What is the end product of the activation unit of the classical pathway?

Answer 43

Formation of C5 convertase

Question 44

What is the second most abundant complement protein?

Answer 44

C4

Question 45

This protein cleaves by C1s to form C4a and C4b

Answer 45

C4

Question 46

What will form if there is a delay in the binding of the C4b to protein which resulted in the reaction with water molecules?

Answer 46

iC4b

Question 47

What are the proteins mainly involved in the activation unit of the classical pathway?

Answer 47

C4 C2

Question 48

Next component to be activated after C4 in the activation unit of the classical pathway

Answer 48

C2

Question 49

This is closely associated with the gene for factor B (alternative pathway) on chromosome 6 in the major histocompatibility complex (MHC class III)

Answer 49

C2 gene

Question 50

When combined with C4b in the presence of magnesium ions C2 is cleaved by C1s to form:

Answer 50

C2a and C2b

Question 51

C2a binds to C4b to form:

Answer 51

C3 convertase

Question 52

Aka C3 convertase

Answer 52

C4b2a

Question 53

What is the half life of C4b2a?

Answer 53

15 seconds to 3 minutes

Question 54

If binding does occur, C3 is cleaved in to two parts:

Answer 54

C3a C3b

Question 55

What is the most significant step in the entire process of complement activation of the classical pathway?

Answer 55

Cleavage of C3 component to form C3a and C3b

Question 56

What are the functions of C3b?

Answer 56

Formation of MAC Acts as an opsonin which enhances phagocytosis

Question 57

What new enzyme is created if C3b is bound within 40 nm of the C4b2a?

Answer 57

C5 convertase

Question 58

Where is the MHC III gene found?

Answer 58

Short hand of the chromosome 6

Question 58

Where is the MHC III gene found?

Answer 58

Short hand of the chromosome 6

Question 59

How close should C2 be to be bound to C1s?

Answer 59

60nm

Question 60

How close should the C4 be to be bound to C1s?

Answer 60

40 nm

Question 60

How close should the C4 be to be bound to C1s?

Answer 60

40 nm

Question 61

Aka C5 convertase

Answer 61

C4b2a3b

Question 62

What is the. Response time of CRP?

Answer 62

6-8 hours

Question 63

What is the response time of Serum Amyloid-A?

Answer 63

24 hours

Question 64

A small peptide which causes the increase vascular permeability

Answer 64

Anaphylatoxins

Question 65

What happens when there is an increase in vascular permeability?

Answer 65

Contraction of smooth muscle and release of histamine from the basophils and mast cells

Question 66

What are the proteins involved in the increase vascular permeability?

Answer 66

C3a C4a C5a

Question 67

What is the beginning of the MAC?

Answer 67

Cleaving of C5 into C5a and C5b by C5 convertase

Question 68

What should happen to achieve lysis?

Answer 68

Binding in the c5 and c9

Question 69

What happens when no binding of c6 occurs to the C5b?

Answer 69

Inactivated

Question 70

Trimolecular complex that has a high affinity for lipid constituents of the cell membrane

Answer 70

C5b67

Question 71

They interact with the cell membrane to form a small hole in the membrane

Answer 71

C7 C8

Question 72

This protein is inserted into the lipid bilayer of the cell membrane

Answer 72

C8

Question 73

What constitutes as the complete lysis of the cell?

Answer 73

Binding of C9 to C5b678