MHC and Complement System

Question 1

Found on surfaces of most nucleated cells of the body; displays what is going on inside the cell especially in the case of viral infection and peptides bound in it are presented to cytotoxic T cells (CD8)

Answer 1

MHC Class I

Question 2

Specialized antigen-presenting cells (3)

Answer 2

macrophages
dendritic cells
B cells

Question 3

Found on specialized antigen-presenting cells; displays what is going on especially in the case of bacterial infection and present exogenous antigens to helper T cells (CD4)

Answer 3

MHC Class II

Question 4

Prevents the binding of endogenous peptides

Answer 4

Invariant chain (Ii, CD74)

Question 5

Facilitates exchange between MHC class II-CLIP complex and peptides

Answer 5

HLA-DM

Question 6

Activated by antibodies bound to antigens; C1 molecule is activated and induces proteolytic cascade

Answer 6

Classical Pathway

Question 7

C4b2b as well as C3bBb are equivalent to?

Answer 7

C3 convertase

Question 8

C3b function

Answer 8

Same as opsonins

Question 9

C4b2b3b as well as C3bBb2bis equivalent to?

Answer 9

C5 convertase

Question 10

C3b5b is important for?

Answer 10

Terminal Classical Pathway

Question 11

Formation of a tubular structure called Membrane Attack Complex (MAC)

Answer 11

C5b678 Complex

Question 12

It effectively punches a hole in the invader; can cause osmotic lysis of the microorganism

Answer 12

Membrane Attack Complex (MAC)

Question 13

Everything is the same from C5b to C5b6789 (until C3 convertase), other than that is different. True or False?

Answer 13

True

Question 14

Triggered by contact between
● microbial cell walls and
● complement components

Answer 14

Alternative Pathway

Question 15

Activated directly by microbial carbohydrates; defense mechanism

Answer 15

Lectin Pathway

Question 16

Most important lectin;

Answer 16

Mannose-Binding Lectin (MBL)

Question 17

Block the activities of active C1r and C1s

Answer 17

C1-INH

Question 18

Decay accelerating factor; binds to convertases and accelerates their decay; function is to protect normal body cells from complement attack

Answer 18

CD-55

Question 19

Inhibit the C56789 insertion and C9
polymerization in cell membranes

Answer 19

CD59 (Protectin)

Question 20

C3b bound to a microbial surface is a very
potent and effective opsonin

Answer 20

Opsonization

Question 21

Small peptides C3a and C5a molecules; degranulate mast cells and stimulate platelets to release vasoactive molecules (histamine and serotonin)

Answer 21

Anaphylatoxins

Question 22

A defense mechanism that can be activated by both innate and acquired immune mechanisms

Answer 22

Complement System

Question 23

Antigen + Antibody =

Answer 23

Active C1

Question 24

Most important complement protein

Answer 24

C3

Question 25

Other acceleration of convertase degradation found in plasma

Answer 25

Factor H & C4-binding protein (C4BP)

Question 26

Other acceleration of convertase degradation found in cell membranes (2)

Answer 26

CD35 and CD46

Question 27

Major contributor to acute inflammation; activation of the complement

Answer 27

Chemotaxis