innate immunity

Question 1

What is the main features of the innate system?

Answer 1

first line of defense
act immediately
instructs adaptive system
clearance of dead tissues and initiation of repair
no memory (system)

Question 1

What is the main features of the innate system?

Answer 1

first line of defense
act immediately
instructs adaptive system
clearance of dead tissues and initiation of repair
no memory (system)

Question 2

What are the first barriers of defense?

Answer 2

anatomic and chemical barriers (usually found on skin and mucosal surfaces)

Question 3

What is the complement system?

Answer 3

proteins that work together to opsonise microbes, promote phagocyte recruitment, and directly kill microbes

Question 4

What is opsonisation?

Answer 4

is the process in which microorganisms is coated by serum components, thereby enhancing recognition and ingestion by phagocytic cells

Question 5

What is an important opsonin?

Answer 5

C3b

Question 6

What does the activation of the complement system release?

Answer 6

C3a, C5a (involved in inflammation)

Question 7

What does C3a and C5a do?

Answer 7

attract and activate neutrophils
activate mast cells (release of histamine and leukotriene = increase vascular permeability)

Question 8

What are cytokines?

Answer 8

any soluble protein that affects the behaviour of cells bearing appropriate receptors

Question 9

What are the major granulocytes?

Answer 9

neutrophil
eosinophil
basophil

Question 10

What are the major profession antigen-presenting cells?

Answer 10

macrophage
dendritic cell

Question 11

What is the major characteristic of nuetrophils?

Answer 11

multilobed nuclei
cytoplasmic granules

Question 12

What are the main functions of neutrophils?

Answer 12

phagocytosis,
degranulation,
release of neutrophil extracellular traps (NETs)

Question 13

What are the main functions of macrophages?

Answer 13

phagocytosis,
antigen presentation

Question 14

What are dendritic cells?

Answer 14

sample antigen and migrate to lymph nodes to present antigen

Question 15

What are the types of dendritic cells?

Answer 15

conventional dendritic cells
plasmacytoid dendritic cells
follicular dendritic cells
tissue resident dendritic cells

Question 16

Plasmacytoid DCs produce what major cytokine?

Answer 16

type I interferons (IFNs)

Question 17

What do all DCs express?

Answer 17

class I and class II MHC molecules –> crucial for presentation of antigens

Question 18

What are the major subsets of innate lymphoid cells (ILCs)?

Answer 18

ILC1, ILC2, ILC3

Question 19

What is the activity of ILC1?

Answer 19

macrophage activation

Question 20

What is the activity of ILC2?

Answer 20

mucus production
vasodilation
macrophage activation
thermoregulation

Question 21

What is the activity of ILC3?

Answer 21

promotion of: phagocytosis; release of antimicrobial peptides; epithelial cell survival

Question 22

What are the major functions of NK cells?

Answer 22

kill infected cells (perforin and granzymes)
secrete cytokines
antibody-dependent mediated cytotoxicity

Question 23

How are pathogens recognised by immune cells?

Answer 23

Phagocytes recognise pathogen associated molecular patterns (PAMPS) with pattern recognition receptors (PRRs)

Question 24

How do PRRs recgonise unique microbial macromolecules?

Answer 24

via repetitive structural proteins

Question 25

What are the types of PRRs?

Answer 25

Toll-like receptors (TLRs)
NOD-like receptors (NLRs)
RIG-like receptors (RLRs)
C-type lectin receptors (CLRs)
Cytosolic DNA sensors (CDSs)

Question 26

What are the two principle types of reactions of the innate immune system?

Answer 26

inflammation
antiviral defense

Question 27

What triggers the reactions of the innate system?

Answer 27

activation of transcription factors

Question 28

What induces an anti-viral state?

Answer 28

IFN-α and IFN-β

Question 29

What are the cardinal signs of inflammation?

Answer 29

redness
warmth
pain
swelling
loss of function

Question 30

What do macrophages release?

Answer 30

inflammatory mediators - TNF, IL1 and IL6

Question 31

Where can inflammatory mediators act?

Answer 31

locally or systemically

Question 32

What is the local effects of inflammatory mediators?

Answer 32

TNF and IL1 act on leukocytes and endothelium to induce acute inflammation
induce expression of IL6

Question 33

What are the systemic effects of inflammatory mediators?

Answer 33

protective = induction of fever
pathologic = decreased cardiac function, shock, thrombosis and capillary leak