Pathogens and the host: innate immunity

Question 1

Innate immunity is rapidly evoked and non-specific. True or false?

Answer 1

True

Question 2

Adaptive immune system is more specific than innate immune system. True or false?

Answer 2

True

Question 3

What are the four soluble factors that the innate immune system uses to provide defence against bacterial infections?

Answer 3

lysozymes
acute phase proteins
complement
interferons (cytokines)

Question 4

what is the role of lysozymes?

Answer 4

splitting of bacterial wall of susceptible bacteria

Question 5

what is the role of acute phase proteins?

Answer 5

opsonisation

attraction of phagocyte and increased blood flow

Question 6

What are complements?

Answer 6

a system of proteins with the role of opsonisation

Question 7

Interferons have antiviral resistance against viral infections. True or false?

Answer 7

True

Question 8

Myeloid cells are used by adaptive immune system and lymphoid cells are used by innate immune system. True or false?

Answer 8

False - myeloid - innate immune system

lymphoid - adaptive immune system

Question 9

Where and how are myeloid stem cells produced?

Answer 9

Pluripotent stem cells produce myeloid stem cells in the bone marrow

Question 10

Lymphocytes are larger than monocytes. True or false?

Answer 10

False - smaller

Question 11

Macrophages are antigen-presenting cells. True or false?

Answer 11

True

Question 12

Where do macrophages reside?

Answer 12

Tissues

Question 13

How do macrophages identify microbes?

Answer 13

by the deployment of different pattern recognition receptors - major ones are called toll-like receptors

Question 14

Neutrophils are the most important cellular component in bacterial destruction. True or false?

Answer 14

True

Question 15

Where are neutrophils found?

Answer 15

In blood - move to tissues only after infection occurs

Question 16

Neutrophils are antigen-presenting cells. True or false?

Answer 16

False

Question 17

What is the function of neutrophils?

Answer 17

Engulfing and destroying extracellular microorganisms

Question 18

Macrophages produce MHC Class I molecules. True or false?

Answer 18

False - MHC Class II

Question 19

What are the four types of PRRs?

Answer 19

Fc receptors
Complement - C3b
Toll-like
Scavenger

Question 20

What are the three stages involved in killing of opsonised microbes?

Answer 20

ingestion of microbe by pseudopodia
metabolic reactions take place in phagosome generating oxygen and nitrogen radicals which damage microbes
formation of phagolysosomes which have conditions e.g. low pH that kill microbes

Question 21

In the killing of opsonised microbes, pseudopodia ingest the microbe. How does this differ in innate and adaptive response?

Answer 21

In innate - complement receptors carry this out
In adaptive - Fc receptors carry this out
both systems require PRRs

Question 22

Basophils are categorised by red granules. True or false?

Answer 22

False - violet-blue granules

Question 23

Basophils are active in allergic responses. True or false?

Answer 23

True

Question 24

Which complements do basophils bind?

Answer 24

C3a, C3b and C5a

Question 25

Which type of cell play an important role in the defence against parasitic infections?

Answer 25

Eosinophils

Question 26

How do eosinophils work?

Answer 26

They gather at a parasitic infection or site of allergic reaction such as asthma they release their toxins, contained in their granules

Question 27

Natural killer cells are only present in innate immune response. True or false?

Answer 27

False - in innate and adaptive response

Question 28

NK cells are phagocytes. True or false?

Answer 28

False

Question 29

How do NK cells recognise virally infected cells?

Answer 29

Secretion of interlukin-12 or interferon-gamma which kills virally infected cells

Question 30

How many receptors do NK cells have and what are they?

Answer 30

2 receptors - inhibitory and activating

Question 31

When both receptors on NK cells are occupied, the NK cell becomes activated. True or false?

Answer 31

False - not activated when both receptors are occupied so doesn't kill virally infected cells

Question 32

When the activating receptor is occupied (not the inhibitory one) what happens?

Answer 32

The NK cells receive a signal to secrete chemicals that kill virally infected cells

Question 33

NK cells distinguish infected and non-infected cells by targeting those with MHC Class I molecules and destroying those cells. True or false?

Answer 33

False - cells which express MHC class I do not get killed by NK cells

Question 34

Virally infected cells inhibit the expression of MHC Class I molecules. What does this result in?

Answer 34

Killing of those cells by NK cells

Question 35

Normal (non-infected) cells respond to interferon-a and interferon-B by increasing expression of MHC Class I. What effect does this have?

Answer 35

Gives inhibitory signal to NK cells so these normal cells do not get killed