Complement And Cytokines

Question 1

What are three phagocytes?

Answer 1

Neutrophils, monocytes/macrophages

Question 2

• kill virally infected and tumor cells
• Produce cytokines

Answer 2

Natural killer cells

Question 3

This enhances phagocytosis, recruit cells, kills cells/bacteria

Answer 3

Complement

Question 4

Accumulation of fluids and white blood cells to localized and remove irritant

Answer 4

Inflammation

Question 5

-set of plasma proteins that work together to facilitate the destruction and removal of pathogens
-Also play a role in regulation of immunity and tissue damage due to auto immune or hypersensitivity reactions

Answer 5

Complement system

Question 6

What are the major functions of complement?

Answer 6

-localized vasodilation and attract phagocytic cells (anaphylatoxins)
-Enhance phagocytosis (Opsonization)
-Lysis of cells, bacteria, viruses [Membrane attack complex MAC] (Form spores in the membrane)
-clearance of soluble immune complexes

Question 7

-Small soluble fragments of complement proteins (C5a, C3a)
-participates in Inflammation (Vasodilation, vascular permeability, activate mass cells, recruits phagocytosis to side of antigen deposition) 

Answer 7

Anaphylatoxins

Question 8

-enhances phagocytosis of complement coated pathogens due to receptors on macrophages or PMN
-C3b and C4b- opsonins

Answer 8

Opsonization

• Remember antibody IgG is also an opsonin 

Question 9

Explain lysis…

Answer 9

-Membrane attack complex MAC formation results in pore
through membrane
-attack cells, extracellular pathogens and virons (Extracellular viruses)
-C5b, C6, C7, C8, C9 Heart sequentially assembled into MAC

Question 10

Soluble immune complexes (Antigen – antibody) In circulation needs to be cleared. If not, what happens? 

Answer 10

Immune complexes deposit in tissues such as kidneys

Question 11

How are immune complexes cleared out of the body? 

Answer 11

-RBC bind to C3 on immune complexes
-RBC carry complexes to spleen and liver for disposal by macrophages

Question 12

What are the three complement pathways?

Answer 12

• classical pathway
• Alternative pathway
• Lectin pathway

Question 13

Pathway that is anybody directed

Answer 13

Classical pathway

Question 14

This pathway is initiated by C1q Binding to immune complexes 

Answer 14

Classical pathway

Question 15

This pathway is associated with innate immunity and can enhance classical pathway

Answer 15

Alternative pathway

Question 16

This pathway is initiated by C3b binding to surface of bacteria

Answer 16

Alternative pathway

Question 17

This pathway is associated with innate immunity

Answer 17

Lectin pathway

Question 18

Mannose-binding Lectin (MBL) Binding to Mannose residues On bacterial cell surface

Answer 18

Lectin pathway

Question 19

What is the order of classical pathway activation?

Answer 19

C1q, C1r, C1s, C4, C2, C3, C5, C6, C7, C8, C9

Question 20

Alternative pathway: Factor ___, Factor ____, and __________.

Answer 20

B, D, properdin

Question 21

What do proteases do?

Answer 21

Cleave proteins

Question 22

Many components become pro teases after cleavage into two fragments. what is an exception?

Answer 22

C2a which is the larger and bound, while C2b is smaller and soluble

Question 23

Many components become pro teases after cleavage into two fragments. What is an example? 

Answer 23

-small Soluble fragment “a”
-Larger bound fragment “b” 

Question 24

Complement system:

C3 Convertase cleaves C3 into ___ and ____

Answer 24

C3a and C3b

-classical: C4b2a (Enzymatic activity)
-Alternative: C3bBb (enzymatic activity)

Question 25

Complement system:

Addition of C3b to C3 convertase results in….

Answer 25

C5 convertase (C5–> C5a + C5b)

Classical: C4b2a3b (Enzymatic activity)
Alternative: C3bBb3b (enzymatic activity) 

Question 26

Alternative can amplify ___________ Pathway

Answer 26

Classical