L4 Complement

Question 1

Complement is a biochemical pathway that is a key part of the innate/adaptive immune system and assists with the innate/adaptive immune system

Answer 1

innate; adaptive

Question 2

complement enhances/eliminates the inflammatory response, enhances/eliminates pathogens and enhances/eliminates the immune response

Answer 2

enhances, eliminates, enhances

Question 3

three steps of complement

Answer 3

1. opsonization
2. inflammation
3. lysis

Question 4

opsonization

Answer 4

acts like a glue to attach substances or antibodies to pathogens to phagocytosis by macrophages (poly-mononuclear neutrophils)

Question 5

inflammation

Answer 5

induces acute inflammation to dilate blood vessels by activating mast cells/basophils and to recruit inflammatory phagocytic cells to eat the invading organism

Question 6

lysis

Answer 6

generates a group of proteins able to penetrate the invading organisms cell wall and induce lysis

Question 7

the order of activation for complement pathways

Answer 7

1. alternating
2. lectin
3. classical

Question 8

alternating pathway

Answer 8

uses C3, activated spontaneously or via microbial surfaces
c3 –> c3a + c3b (c3b binds to pathogen and can help in opsonization or be converted to C3 convertase), or form C5 convertase whiich can help form membrane attack complex

Question 9

C3 is present in the circulation system and is produced by the

Answer 9

liver

Question 10

lectin pathway

Answer 10

activated via microbial surfaces
ex. mannose
mannose binding protein binds to mannose present on bacteria surface, C2 –> C2a + C2B and C4 –> C4a + C4b, C4b and C2b combine to form C3 convertase whcih helps convert C3 to C3b and C3a, C3b will eventually help form C5 convertase which can lead to MAC

Question 11

classical pathway

Answer 11

activated via antibody attachment and Fc portion, C1
C2 –> C2a + C2B and C4 –> C4a + C4b, C4b and C2b combine to form C3 convertase which helps convert C3 to C3b and C3a, C3b will eventually help form C5 convertase which can lead to MAC

Question 12

lectins activate the _____ pathway

Answer 12

lectin

Question 13

the common goal of the three pathways is to deposit clusters of _________ on a target

Answer 13

C3b

Question 14

anaphylatoxins

Answer 14

increase vascular permeability

C3a, C4a, and C5a

Question 15

chemoattractants

Answer 15

attract neutrophils and monocytes

C3a C5a

Question 16

membrane attack complex (MAC)

Answer 16

final phase of complement- C5b-9
lysis
creates perforations in cellular membranes

Question 17

C3b functions as an

Answer 17

opsonin

Question 18

microbes coated in C3b are ________ by virtue of C3b being recognized by complement receptor type I (CR1)

Answer 18

phagocytosed

Question 19

____________ helps to down-regulate the C3 convertase

Answer 19

decay accelerating factor (DAF)

Question 20

people with lack of DAF

Answer 20

• uncontrolled complement

- leads to RBC lysis

Question 21

RBC lysis

Answer 21

paroxysmal nocturnal hemoglobinuria (PNH)

Question 22

C1 inhibitor

Answer 22

protease inhibitor that down regulated C1 activation in the classical pathway of complement

Question 23

people who lack C1 inhibitor

Answer 23

uncontrolled C1 activation
excessive vasoactive peptides
can lead to angiodema

Question 24

how does C1 inhibitors regulate angiodema?

Answer 24

C1 inhibits bradykinin pathway

Question 25

assay for alternative pathway

Answer 25

AH50

Question 26

assay for lectin pathway

Answer 26

MBL

Question 27

assay for classical pathway

Answer 27

CH50

Question 28

C3 deficiency

Answer 28

profound risk of encapsulated bacteria infection

Question 29

C1, C2, C4 DEFICIENCY

Answer 29

associated with increased risk of immune complex disease example would be systemic lupus erythematosus (SLE)

Question 30

C1 inhibitor deficiency

Answer 30

excess of vasoactive peptides (bradykinin)

Question 31

C5b, C6, C7. C8, C9 deficiency

Answer 31

increased susceptibility to Neisseria and meningitidis infections due to not being able to form MAC

Question 32

MAC can induce lysis only on cells that have thin cell walls such as

Answer 32

neisseria species

Question 33

``` The Classical pathway of Complement is activated following antibody:antigen interaction with what component? C1q (and C1r-C1s) C3 convertase C5a C5b, C6, C7, C8, C9 ```

Answer 33

C1q (and C1r-C1s)

Question 34

T/F Complement activation typically occurs in the order of Alternative, Lectin, and Classical pathways, respectively.

Answer 34

T

Question 35

t/f Complement components C6, C7, C8, and C9 comprise the anaphylatoxins.

Answer 35

false

Question 36

T/F Complement component C5a is an opsonin because it coats/labels bacteria.

Answer 36

false

Question 37

``` Invasive meningococcal (Neisseria meningitidis) disease and disseminated gonococcal (Neisseria gonorrheae) infections are the only conditions (i.e. no autoimmune diseases) known to be associated with complement deficiencies in: C3 C1q C8 C4 C1 inhibitor ```

Answer 37

C8

Question 38

The highest rates of meningococcal disease are seen in infants, who have little natural antibody against Neisseria. Older teens and young adults have much higher rates of colonization (on mucous membranes), higher levels of antibody, but lower levels of disease. Which pathway of complement activation could involve this specific antibody?

Answer 38

classical

Question 39

You are called to see a patient with severe disease due to meningococcemia in the ICU. He has purpura fulminans and sequelae of sepsis including multisystem organ disease including liver and kidney failure. The resident ordered a CH50 and the result is low. You are trying to decide if this is more likely an acquired or inherited terminal complement deficiency. Which of the following is FALSE: 1. Testing for decreased levels of multiple complement components may help distinguish acquired from the inherited defect 2. Testing total complement after recovery of this illness may help distinguish acquired from inherited defect 3. Liver failure is a cause of low CH50 4. Vasculitis is a cause of low CH50 5. Obtaining an AH50 to test function of the alternate pathway may help to distinguish acquired from the inherited defect

Answer 39

5. Obtaining an AH50 to test function of the alternate pathway may help to distinguish acquired from the inherited defect

Question 40

The three main anatomic locations involved in attacks of hereditary angioedema are: Lower extremities, genitalia, abdomen Eyelids, upper extremity, upper airway Upper extremity, neck, gastrointestinal tract Lower extremities, gastrointestinal tract, skin Skin, upper airway, gastrointestinal tract

Answer 40

Skin, upper airway, gastrointestinal tract

Question 41

``` Pathogenesis of angioedema in hereditary angioedema is predominantly mediated by excess: Histamine C1 Inhibitor C3 Bradykinin Membrane Attack Complex ```

Answer 41

Bradykinin

Question 42

``` In Hereditary C1 Inhibitor Deficiency, on would expect the following complement levels: Low C4, Low C1 Inh Low C4, High C1 Inh Normal C4, Low C1 Inh Normal C4, High C1 Inh High C4, High C1 Inh ```

Answer 42

Low C4, Low C1 Inh

Question 43

hereditary angioedema

Answer 43

disease due to defect in C1 inhibitor decreadsed levels of C4 and C2 autosomal dominant plasma derived C1 inhibitor

Question 44

neisseria meningitidis

Answer 44

gram negative cocci produces polysaccharide capsule - major virulence factor complement deficiencies in C8