Compliment System

Question 1

complement system

Answer 1

part of the immune system that enhances the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promotes inflammation, and attacks the pathogen’s cell membrane

Question 2

Is the compliment system part of innate or adaptive immunity?

Answer 2

Innate however this system can be recruited and brought into action by antibodies generated by the adaptive immune system

Question 3

Factor H

Answer 3

Regulates the alternative pathway ensuring that the compliment system does not attack host.

Question 4

Elements of innate immune system

Answer 4

mucous secretions, compliment proteins, and certain white blood cells including neutrophils, macrophages, and dendritic cells

Question 5

What are the two major functions of the compliment system?

Answer 5

1. Alters the membrane of pathogens and debris (opsonization)
2. Enhances the inflammatory response via release of anaphylatoxins that promote cell activation or migration to inflammatory site

Question 6

Chemotaxis

Answer 6

Migration to inflammatory site

Question 7

Mechanisms of complement system activation

Answer 7

1. Spontaneous turnover of C3 engages the alternative pathway
2. Binding to the target of Abs engages the classical pathway
3. Binding of lectins to carbs on target engages the lectin pathway

Question 8

Immune functions triggered by complement

Answer 8

1. Phagocytosis via opsonization (C3b)
2. Inflammation by attracting macrophages and neutrophils (C3a and C5a)
3. Membrane attack on invading cell

Question 9

What are the three complement pathways?

Answer 9

1. Classic
2. Mannose-Binding Lectin
3. Alternative

Question 10

What is the classical pathway triggered by?

Answer 10

Activation of the C1-complex via antigen binding to antibody

Question 11

Which pathway is homologous to the classical pathway?

Answer 11

Mannose-binding lectin; There is no C1 complex however C2 and C4 are still present

Question 12

Alternative pathway

Answer 12

Continuously activated at a low level, as a result of spontaneous C3 hydrolysis. Does not rely on pathogen-binding antibodies like the other pathways.

Question 13

CD59 (protectin)

Answer 13

Protects you from attacking yourself

Question 14

DAF/Factor I

Answer 14

Prevents the formation of additional C3 convertase which is a common factor in all three activation pathways of the human complement system (also C5 convertase)

Question 15

Paroxysmal nocturnal hemoglobinurina

Answer 15

• Results in premature death and impaired production of blood cells (RBC, leukocytes, platelets) due to attack from the compliment system
• Affects both sexes equally, deficiency in DAF protein

Question 16

Atypical hemolytic uremic syndrome

Answer 16

• Results from chronic uncontrolled activation of the complement system
• Multiple blood clots throughout the body which can lead to stroke, heart attack, kidney failure, and death
• Mutation in Factors I/H or membrane cofactor protein

Question 17

Hereditary Angioedema

Answer 17

• Recurrent attacks of severe swelling
• Type I is deficiency of C1
• Type II is atypical C1
• Type III due to mutations in Factor XII gene

Question 18

Sleep deprivation can lead to the activation of what?

Answer 18

pro-inflammatory cytokines and activation of the innate immune system