The Complement System

Question 1

Complement consists of a group of __________ proteins circulating in inactive form.

Answer 1

serum

Question 2

Once activated, the catalytic cascade can lead to multiple possible outcomes. Name 3 discussed in class.

Answer 2

1. Directly lyse target cell membrane
2. Chemotaxis
3. Opsonization to enhance phagocytosis

Question 3

What are the three pathways of complement activation?

Answer 3

1. Classical
2. Lectin
3. Alternative

Question 4

CR1 is expressed on ________________ and ________________.

Answer 4

leukocytes and erythrocytes

Question 5

C3aR and C5aR are expressed on __________________.

Answer 5

granulocytes

Question 6

C3aR and C5aR stimulate the release of ________________ cytokines. The “a” in their name refers to ________________.

Answer 6

pro-inflammatory; anaphylatoxins

Question 7

Which receptor is involved in removal of immune complexes?

Answer 7

CR1

Question 8

The classical pathway begins with the formation of ________________________.

Answer 8

Antigen-antibody complexes

Question 9

The lectin pathway is initiated when ______________ proteins recognize ______________ ______.

Answer 9

soluble; microbial Ags

Question 10

The alternative pathway is initiated in __________ ways.

Answer 10

three

Question 11

Which pathway is initiated by IgM or IgG binding to a multivalent antigen?

Answer 11

classical

Question 12

Small amounts of _____ are always being cleaved.

Answer 12

C3

Question 13

In the _____________ pathway, MBL binds to microbial surfaces and serve as a docking site for MBL associated serine proteases (MASPs).

Answer 13

lectin

Question 14

MASPs cleave _____ and ______ to form the _________________.

Answer 14

C2; C4; C3 convertase

Question 15

The planar form of IgM has many more C1q binding sites than the staple form of IgM. T or F?

Answer 15

FALSE; the opposite is true

Question 16

Monomeric IgG has how many binding sites for C1q per molecule?

Answer 16

one; it is therefore less efficient at activating complement than IgM

Question 17

The three complement pathways converge at the formation of the ___ ______________.

Answer 17

C5 convertase

Question 18

C5 initiates the generation of what system?

Answer 18

MAC - membrane attack complex

Question 19

The membrane attack complex is the result of ______________________________________.

Answer 19

the deposition of C proteins

Question 20

C protein deposition results in a ______ structure, which disrupts ____________ integrity, resulting in ________ __________.

Answer 20

pore; osmotic; cell death