innate immunity

Question 1

what is innate immunity?

Answer 1

fast (1-4 days) first line of non-specific defence

Question 2

what is adaptive immunity?

Answer 2

slow long lived specific and acquired

Question 3

what do both innate and adaptive immunity have?

Answer 3

cellular components and humoral components

Question 4

what are humoral components?

Answer 4

antibodies

Question 5

what is tissue homeostasis?

Answer 5

A homeostatic process involved in the maintenance of an internal steady state within a defined tissue of an organism, including control of cellular proliferation and death and control of metabolic function.

Question 6

what is immune response in healthy indiviuals?

Answer 6

low to prevent uneccessary inflammation

Question 7

what happens to the immune system during disease?

Answer 7

homeostasis is shifted to prevent infectious pathogens from entering the body and causing disease

Question 8

is the innate immune system effective?

Answer 8

yes- regular contact with potential pathogens which are destroyed within minutes or hours, only rarely causing disease

Question 9

what are non professional immune cells?

Answer 9

epithelial/endothelial cells + fibroblasts (contribute to innate immune system to prevent infection)

Question 10

what are the three parts of the innate immune system?

Answer 10

• epithelium
• innate cell subsets and compliment
• chemokines/cytokines

Question 11

what is epithelium’s role in innate immunity?

Answer 11

Physical barrier
Produces antimicrobial peptides
Produces cytokines/chemokines

Question 12

what are the innate cell subsets?

Answer 12

Phagocytic cells (macrophages, neutrophils)
Antigen-presenting cells (dendritic cells)

Question 13

what are the roles of chemokines and cytokines in innate immunity?

Answer 13

Chemokine – Cell recruitment
Cytokine – Cell activation/proliferation

Question 14

what are the components of innate immunity?

Question 15

what is the role of physical barriers (epithelium) in innate immunity?

Answer 15

Epithelial barriers produce a number of different compounds e.g., in the oral cavity the following are produced;
Antimicrobial peptides
Immunoglobulins (secretory IgA)
Lactoferrin
Lysozyme
Cystatins
Epithelium provides structural/mechanical support

Question 16

what do antimicrobial peptides do?

Answer 16

help to destroy the pathogens (kill microbes by binding to their membrane) or inform the immune system to respond (neutralise microbial virulence factors)

Question 17

what are examples of antimicrobial peptides?

Answer 17

β-defensins
Human Neutrophil Peptides (HNPs)
Cathelicidins (e.g., LL-37)
Psoriasin proteins (S100 family)

Question 18

what do SIgAs do?

Answer 18

secretory immunoglobulin A
- coat microbes for host recognition
- produced at mucosal surfaces
- binds to flagella and can prevent motility
- binds to and neutralizes bacterial toxins
- cross links target macromolecules and bacteria therefore trapping them and preventing effects on mucosa
- prevents attachment of bacteria to mucosal surfaces

Question 19

what does lactoferrin do?

Answer 19

glycoprotein that transports iron ions, has antimicrobial activity
- present in saliva
- produced by neutrophils

Question 20

what do lysozymes do?

Answer 20

target cell walls of bacteria
- present in saliva
- produced by macrophages and neutrophils

Question 21

what do cystatins do?

Answer 21

anti-protease activity and support remineralisation of teeth

Question 22

what is microbial recognition by the host?

Answer 22

• Cells involved in immune responses have receptors for components of microorganisms (antigens)
• Toxins and virulence factors = microbial antigens
• Receptor activation orchestrates the immune response
• Different receptors recognize different antigens from different pathogens

Question 23

what is an example of a receptor which recognises microbes?

Answer 23

toll-like receptors

Question 24

What do toll like receptors recognise?

Answer 24

recognise bacteria and fungi

Question 25

what do intracellular receptors do?

Answer 25

recognise viruses

Question 26

what are examples of toll-like receptors?

Answer 26

TLR2 TLR4

Question 27

what do dectin and glucan receptors recognise?

Answer 27

fungi

Question 28

what do NOD receptors recognise?

Answer 28

bacteria

Question 29

what is PRR?

Answer 29

pattern recognition receptor - recognise microbes

Question 30

what is PAMPS?

Answer 30

pathogen associated molecular patterns

Question 31

describe the host cell pathogen interaction sequence

Question 32

what are cytokines?

Answer 32

- small proteins

Question 33

what are examples of cytokines?

Answer 33

- Interleukin family (e.g. IL-1α, IL-1β, IL-6, IL-8 etc) - TNF family (e.g. TNF-α) - Interferons (e.g., IFN-γ) - “unassigned” (e.g., TGF-β)

Question 34

what are the three function categories of cytokines?

Answer 34

autocrine paracrine endocrine

Question 35

describe cytokine binding

Answer 35

- induces conformational changes in a majority of receptors intracellularly - signal transduction – leads to the activation of transcription factors that leads to control of gene regulation

Question 36

what can both PRR signalling and cytokine receptor signalling lead to?

Answer 36

the transcription and subsequent translation of certain proteins

Question 37

what is chemotaxis?

Answer 37

the movement of a cell in a direction corresponding to a gradient of increasing or decreasing concentration of a particular substance (e.g., chemokines)

Question 38

what are the four classes of chemokines?

Answer 38

- C chemokines (2 members) - CC chemokines (31 members) - CXC chemokines (18 members) - CX3C chemokines (1 member)

Question 39

which chemokine plays an important role in oral mucosa?

Answer 39

CXCL8

Question 40

what is the most prominent cell at the oral mucosa?

Answer 40

neutrophils

Question 41

what happens to neutrophils during inflammation?

Answer 41

- increase in number - attracted along a CXL8 (IL-8) (interleukin 8) gradient to site of inflammation

Question 42

what is the name of cells which control interactions between immune cells and endothelial cells?

Answer 42

cell adhesion molecules

Question 43

what are the three main families of adhesions/receptors?

Answer 43

Selectins (e.g., P and E- selectins) Integrins (e.g., LFA-I) Immunoglobulin superfamily

Question 44

which receptor types are generally found of endothelial cells?

Answer 44

selectins and immunoglobin

Question 45

which receptor types are generally found on migrating immune cells?

Answer 45

integrins

Question 46

what is degranulation by neutrophils?

Answer 46

Granules in cell (known as vesicles) containing numerous antimicrobial peptides and enzymes Released upon activation of receptors (e.g. TLRs)

Question 47

what are neutrophil extracellular traps?

Answer 47

Activation induces neutrophils to release proteins and some genetic material (chromatin) to form extra-cellular fibril matrix Trap pathogens Many antimicrobials also associated with the NET so bacteria ‘held’ whilst ‘administered’

Question 48

how do monocytes migrate to tissues?

Answer 48

similarly to neutrophils, via cell adhesion molecules

Question 49

what are the pro-inflammatory machrophages?

Answer 49

M1

Question 50

what are the anti-inflammatory macrophages?

Answer 50

M2

Question 51

what are the two types of antigen presenting cells?

Answer 51

non-professional professional

Question 52

what are examples of non-professional antigen presenting cells?

Answer 52

Epithelial cells/fibroblasts/endothelial cells

Question 53

what are examples of professional antigen presenting cells?

Answer 53

macrophages and dendritic cells

Question 53

what are examples of professional antigen presenting cells?

Answer 53

macrophages and dendritic cells

Question 54

phagocytosis

Question 55

antigen presentation

Answer 55

Antigen presentation is the expression of antigen molecules on the surface of a macrophage or other antigen-presenting cell in association with MHC class II molecules when the antigen is being presented to a CD4+ helper T cell or in association with MHC class I molecules when presentation is to CD8+ cytotoxic T cells.

Question 56

degranulation

Question 57

which cell types can drive degranulation?

Answer 57

mast natural killer monocyte macrophage neutrophil

Question 58

what is the largest component of human blood?

Answer 58

plasma (composes 55%)

Question 59

what are the four enzymatic cascades systems in plasma?

Answer 59

- complement - kinins - coagulation factors - fibrinolytic system

Question 60

what is the complement cascade system in plasma?

Answer 60

- A collection of soluble proteins present in circulation. - Drives inflammation or opsonisation - Opsonisation refers to coating of pathogens by antibodies or complement proteins - Three pathways; classical, alternative or lectin pathway

Question 61

what is the classical pathway of complement?

Answer 61

antibody attached to microbe

Question 62

what is the alternative pathway of complement?

Answer 62

microbial cell wall

Question 63

what is the mannose binding lectin pathway of complement?

Answer 63

carbohydrates on pathogen surface

Question 64

what are anaphylotoxins?

Answer 64

- lead to smooth muscle contraction and capillary leakage – allowing increased infiltration of immune cells to site of infection

Question 65

what triggers the complement cascade?

Answer 65

initiating factor

Question 66

C3- C5

Question 67

what are the functions of anaphylatoxins?

Answer 67

- Promote immune cell recruitment - Increase adhesion of cells to vessel walls - Induces granulation - Promotes cytokine production - Induces antigen presentation - Regulate adaptive immune responses