Deck 5: The Complement System

Question 1

Each complement component below is an anaphylotoxin except

A)C3a
B)C4a
C)C5a
D)C2a

Answer 1

C2a

Question 2

Which complement regulatory protein is expressed on red blood cells to prevent them from being damaged by complement?

A)C4 binding protein
B)C1 inhibitor
C)S protein
D)Factor H
E)decay accelerating factor

Answer 2

decay accelerating factor

Question 3

The abbreviation C3a in relation to complement gives what information?

A)The capital C indicates this is a complement component.
B)The lower case letter indicates that this is a fragment of the component.
C)The numeral tells which complement component.
D)All of the above.

Answer 3

All of the above.

Question 4

Which of the following is TRUE regarding the C3 convertase in the classic complement pathway?

A)Magnesium is required to stabilize the complex.
B)It is incorporated into the membrane attack unit.
C)It is inactivated once it splits a C3 molecule into C3a and C3b.
D)Its composition is C2bC4a.
E)All of the above.

Question 5

All of the following can activate the alternate pathway of complement except

A)mannose.
B)lipopolysaccharides from gram negative bacteria.
C)teichoic acid from gram positive bacteria.
D)certain fungal cell walls.
E)certain parasites.

Question 6

Which of the following are TRUE regarding the alternate pathway of complement activation?

A)Factor D has a similar function to C1qrs, and Factor B has a similar function to C2.
B)The activation surface of an organism serves to spontaneously cleave C3 into C3a and C3b.
C)Unlike the classic complement pathway, the alternate pathway is independent of calcium and magnesium.
D)The composition of the C3 convertase is a Factor B/Properdin complex.

Question 7

Which of the following is TRUE regarding paroxysmal nocturnal hemoglobinuria (PNH)?

A)It can be diagnosed by the deficiency of CD55 and CD59 on red blood cells.
B)Red blood cells are deficient in the complement regulatory proteins DAF (decay accelerating factor)and protectin.
C)Symptoms include lysis of red blood cells with hemoglobin appearing in the urine and a tendency to develop blood clots.
D)All of the above.

Question 8

When antigen binds to antibody, the is (are)activated.

A)mannose binding pathway
B)alternate pathway
C)classic pathway
D)All of the above

Question 9

Which complement regulatory protein(s)below act(s)to prevent initial complement activation? (Check as many as apply.)

A)C1 inhibitor
B)decay accelerating factor
C)Factor I
D)C4 binding protein
E)Factor H

Question 10

All of the following are functions of complement except

A)chemotaxis.
B)specific, selective antigen binding.
C)anaphylotoxin.
D)cell lysis.
E)opsonization.

Question 11

In what way(s)is complement antiviral?

A)Can opsonize viral particle.
B)Can directly disrupt viral particle.
C)Can block viral receptors.
D)All of the above.

Question 12

All of the following conditions have been associated with deficiencies in complement regulatory proteins except

A)hereditary angioedema.
B)paroxysmal nocturnal hemoglobinuria.
C)chronic susceptibility to Neisseria infections.
D)systemic lupus erythematosus.
E)hemolytic- uremic syndrome.

Question 13

What is (are)the consequence(s)of complement C5 being cleaved into C5a and C5b?

A)C5a perforates the cell membrane.
B)C5b binds to C6, C7, C8, and C9.
C)C5b is released into the plasma as a potent anaphylotoxin.
D)All of the above.

Question 14

What is the recognition unit in the classic complement pathway?

A)Factor B and properdin
B)mannose and mannose binding lectin
C)C2 and C4
D)C1qrs
E)C3

Question 15

Each complement component below is an opsonin except

A)C4a
B)C3b
C)iC3b
D)C1qrs

Question 16

All of the following are properties of complement fragment C5a except

A)promotes ability of neutrophils to adhere to blood vessel walls.
B)serves as initial binding molecule of the membrane attack complex.
C)promotes increases expression of complement 1 receptor on phagocytes.
D)promotes adherence of red blood cells, lymphocytes, and endothelial cells to material requiring phagocytosis.
E)most potent chemotactic fragment.

Question 17

Complement components are completely destroyed if a specimen is

A)kept at body temperature for 30 minutes.
B)kept at room temperature for 30 minutes.
C)frozen.
D)heated to 56° C for 30 minutes.
E)All of the above.

Question 18

Which of the following cell wall components can initiate the mannose binding lection pathway of complement activation?

A)Glucose
B)Mannose
C)Fucose
D)N- acetylglucosamine
E)All of the above

Question 19

What is (are)the consequence(s)of complement C3 being cleaved into C3a and C3b in the classic pathway?

A)C3b complexes with C2a4b to form C5 convertase.
B)C3a enters the plasma as an anaphylotoxin.
C)C3b attaches to the cell membrane as an opsonin.
D)All of the above.

Question 20

A person with a genetic deficiency in complement C3 would be predisposed to have

A)immune complex diseases.
B)accelerated, chronic inflammatory reactions.
C)recurrent bacterial infections.
D)autoimmune diseases.
E)no discernible effect since deficiencies in the classic pathway can be compensated for by the alternate and mannose binding lectin pathways.

Question 21

If complement CH50 is decreased and complement AH50 is normal in a specimen, the specimen may be deficient in factor(s)

A)properdin.
B)C3.
C)C1, C2, or C4.
D)Factor B.
E)C5, C6, C7, C8, or C9.

Question 22

In the complement fixation test, the presence of an antibody/antigen reaction is detected because

A)it precipitates complement proteins.
B)complement C5-9 are consumed in the specimen.
C)complement is bound and is unavailable to lyse sensitized red blood cells.
D)complement is activated and it lyses red blood cells.
E)complement C3 is consumed in the specimen.

Question 23

Systemic lupus erythematosus is highly associated with C1q genetic deficiency.

Question 24

The complement system is a group of proteins solely comprised of activators and substrates for the system.

Question 25

For each of the three complement pathways, once C5 is split into C5a and C5b, formation of the membrane attack complex is identical for all three paths.

Question 26

The alternate complement activation path and the mannose binding lectin path both function completely independent of antibody.

Question 27

The activated components of complement are generally very stable to promote a long period of activity and shortened time of infection.

Question 28

The only complement receptor on red blood cells is .

Question 29

Name one complement regulatory protein that inhibits the membrane attack complex.

Question 30

Complement fragments only attach to foreign cells, not host cells.

Question 31

The most abundant complement component in plasma is .

Question 32

The cells with receptors for the anaphylotoxins are .

Question 33

How should specimens be collected and stored if they are to be tested for complement activity?

A)Serum can be refrigerated but not frozen.
B)Serum should be separated from red blood cells.
C)Serum can be stored one to two hours at room temperature prior to testing.
D)All of the above.

Question 34

Hereditary angioedema is associated with a deficiency in .

Question 35

The only complement receptor on red blood cells is CR4.

Question 36

A complement fixation test is done to see if a specimen contains antibodies to rubella virus. A control negative for antibodies and a control positive for antibodies are run, and the sensitized sheep cells are tested alone with no specimen or complement added. Which of reactions below is correct if the specimen does contain antibodies?

A)Positive control, no lysis; negative control, lysis; specimen, no lysis; red cells no lysis
B)Positive control, lysis; negative control, no lysis; specimen, lysis; red cells lysis
C)Positive control, lysis; negative control, no lysis; specimen, lysis; red cells no lysis
D)Positive control, no lysis; negative control, lysis; specimen, no lysis; red cells lysis

Question 37

When there is a complement deficiency, the CH50 increases.

Question 38

The C3 convertases for the classic and mannose binding lectin paths of complement activation are identical.

Question 39

A specimen has a reduced total hemolytic complement as measured by CH50. When individual components were measured, total C3 was very reduced, but total C4 was within normal limits. How can these results be best explained?

A)The subject has severe liver disease.
B)There has been a recent significant activation of the mannose binding lectin complement path.
C)There has been a recent significant activation of the alternate complement path.
D)There has been a recent significant activation of the classic complement path.

Question 40

Complement activity of the alternate pathway can be assessed using rabbit red blood cells.

Question 41

List the three stages of complement cascade.

Question 42

Explain why one molecule of IgM can activate complement but it takes about 1000 molecules of IgG on a cell surface to activate complement.

Question 43

Discuss how the anaphylotoxin complement fragments promote a better immune response.

Question 44

Describe the mechanism of acquired (nongenetic)complement deficiency.

Question 45

Explain how genetic deficiencies of early complement components are associated with immune complex and autoimmune disorders such as systemic lupus erythematosus.