0408 Principles of innate immunology

Question 1

Which immune system is characterised by specificity inherited in the genome?

Answer 1

Innate immunity

Question 2

Which immune system is characterised by an immediate trigger response and which is characterised by a delayed, signal response.

Answer 2

Innate immunity = immediate response. Adaptive immunity = signal response

Question 3

Which immune system recognizes broad classes of pathogens and which recognizes specific types of pathogens

Answer 3

Innate immunity = broad classes of pathogens. Adaptive immunity = specific types of pathogens

Question 4

Which immune system is able to discriminate between closely related molecular structures

Answer 4

Adaptive immune system

Question 5

Which immune system is encoded in multiple gene segments

Answer 5

Adaptive immune system

Question 6

Describe some of the barriers of the innate immune system

Answer 6

Epithelial barriers are the first line of define: skin, epithelial cells on gut, lungs and eyes/nose. Other physical barriers include mucus (lungs,nose,throat). Fatty acids, antibacterial peptides and enzymes (stomach,etc)

Question 7

What are the 2 broad categories of viruses that cause disease in humans (think molecular level)

Answer 7

DNA (e.g. parvovirus, hperpesvirus) and RNA viruses (e.g.retroviruses, coronaviruses)

Question 8

What are macrophages? Describe their general role

Answer 8

Macrophages are phagocytes derived from monocytes.
Roles:
• Phagocytosis - engulf and then digest, cellular debris and pathogens
• Anitgen presenting cell- display antigens with MHC
• Cytokine production - Rounding other cells e.g. neutrophils

Question 9

Where do you find macrophages?

Answer 9

Damaged tissues – monocytes from the circulation enter damaged tissue and change to macrophages

Question 10

What are neutrophils? Describe their general role

Answer 10

Neutrophils are white blood cells formed from bone marrow.
Role
• Phagocytosis - engulf and then digest, cellular debris and pathogens

Question 11

Where do you find neutrophils

Answer 11

Circulation – floating in the plasma of systemic circulation. They move to damaged tissue through the endothelium of vessels

Question 12

What are dendritic cells? Describe their general role

Answer 12

Dendritic cells are specilized antigen-presenting cells. Their main function is to process antigen material and present it on the cell surface to the T and B cells

Question 13

What are dendritic cells? describe their general role

Answer 13

Dendritic cells are antigen presenting cells. They are present in external tissues. Once activated they move to lymph nodes to activate T, NK and B cells

Question 14

What are eosinophils and mast cells? Describe their general role

Answer 14

Eosinophils and Mast cells are both components of plasma what are involved in the activation of an allergy response. Eosinophils are involved in protection against anti-body coated parasites and mast cells contain heparin and histamine

Question 15

Where do you find Eosinophils and Mast cells

Answer 15

Systemic circulation – floating in plasma

Question 16

What are natural killer cells? Describe their general role

Answer 16

NK cells are lymphocytes of the innate immune system. They protect us from infected cells and tumours by detecting MHC absence or abnormality on infected cell surfaces, triggering cytokine release, causing lysis or apoptosis.

Question 17

What do dead neutrophils form?

Answer 17

Pus

Question 18

Name the 2 (professional) antigen presenting cells in the innate immune system

Answer 18

Dendritic cells and macrophages

Question 19

What are pathogen-associated molecular patterns (PAMPs)

Answer 19

PAMPs are molecules associated with groups of pathogens. PAMPs are proteins, nucleic acids or lipids which we don’t have, or which have modifications to them that make them dissimilar to ours

Question 20

What are the 4 main types of recognition receptors

Answer 20

TLRs (toll-like receptors), C-type lectin receptors, NLRs (nucleotide-binding oligomerization domain receptors) and RLRs (RIG-I like receptors)

Question 21

Which of the 2 types of receptors are found in the cell surface and which are found in the cytosol?

Answer 21

Surface= TLRs and C-type lectin receptors

Cytosol= NLRs and RLRs

Question 22

Which 2 types of receptors recognize PAMPs and DAMPs

Answer 22

TLRs and NLRs

Question 23

What are damage-associated molecular pattern molecules (DAMPs)

Answer 23

DAMPs are molecules released by stressed cells undergoing necrosis that act as danger signals to promote and exacerbate the inflammatory response

Question 24

Describe the role of Toll-like receptors (TLRs)

Answer 24

TLRs are cell surface protein receptors responsible for defence against microbial infection. They recognize PAMPs and DAMPs and initiate the signal cascade to activate proinflammatory cytokines

Question 25

Describe the role of C-type lectin receptors (CLRs)

Answer 25

CLRs are cell surface protein receptors the recognize microbial polysacharaides. They bind to carbohydrates released/attached to pathogens and activate the signal cascade to activate proinflammatory cytokines

Question 26

Describe the role of NLRs (nucleotide-binding oligomerization domain receptors) ?

Answer 26

NLRs are cytosolic protein receptors that recognize peptidoglycans in bacterial walls. They detect intracellular PAMPs and DAMPs and cooperate with TLRs to regulate inflammatory and apoptosis response

Question 27

Describe the role of RLRs (RIG-I-Like Receptors) ?

Answer 27

RLRs are cytosolic protein receptors that recognize intracellular virus replication. They sense double stranded RNA, an intermediate in virus replication and produce interferons in infected cells.

Question 28

List the 3 pathways compliment proteins use to converge on activation of C3 convertase

Answer 28

Classical, alternative and lectin pathway

Question 29

What are the 2 activated forms of C3 and what is each form responsible for ?

Answer 29

C3a= enhancing inflammation. C3b = opsonization (promote macrophage phagocytosis) and initiating the membrane attack complex (lysis)