BAMS: Pathology and immunity (innate immunity 1)

Question 1

what is inflammation?

Answer 1

the immune response
aimed at eliminating the inciting cause

Question 2

what are 4 examples of an inciting cause for an inflammatory reaction?

Answer 2

1. invading microorganisms
2. particulate materials (allergens or prostheses)
3. altered self cells (growth disorders/cell injury)
4. transformed malignant cells (neoplasia)

Question 3

what is an example of an acute inflammatory condition?

Answer 3

gingivitis - can be reversible

Question 4

what is an example of a chronic inflammatory condition?

Answer 4

periodontitis - immune system fails to resolve and prevent inciting cause from causing excessive damage

Question 5

what are 4 examples of responses/processes utilised by innate immune cells in response to pathogenic threat?

Answer 5

phagocytosis
degranulation
antigen presentation
mediator release

Question 6

what type of support does epithelium in the oral cavity provide?

Answer 6

structural, mechanical (physical barrier) and immunological support

Question 7

what are the different types of epithelium in the oral cavity?

Answer 7

lining mucosa (buccal mucosa)
masticatory epithelia
tongue mucosa
crevicular/junctional epithelia

Question 8

what compounds are produced by epithelial barriers in the oral cavity?

Answer 8

antimicrobial peptides
secretory IgA
lysozyme

lactoferrin
cystatins

(important in supporting teeth structures)

Question 9

what can be found in oral secretions (saliva, gingival crevicular fluid GCF)?

Answer 9

the compounds produced by epithelia:
e.g., antimicrobial peptides
secretory IgA
lysozyme

lactoferrin
cystatins

Question 10

what is secretory IgA?

Answer 10

an antibody produced by B cells

Question 11

what are cathelicidins?

Answer 11

examples of antimicrobial peptides (AMPs) (e.g., LL-37)

–> main type of AMPs in saliva and sweat, tears etc.,

Question 12

what do antibodies and AMPs do to microorganisms in oral cavity?

Answer 12

attach and disrupt microorganisms membranes, preventing them from damaging oral cavity

Question 13

what is lysozyme?

Answer 13

an enzyme found in saliva

Question 14

what is the shape of lyzosymes?

Answer 14

C shape - active site in the gap in the middle - uses pincers to target components of bacterial cell wall

Question 15

what do lysozymes do to microorganisms?

Answer 15

cleaves proteins within cell wall of bacteria - cleavage of this protein leads to lysis of cell

or can migrate across cell wall of microorganisms and embed into membrane - leading to lysis of cell

Question 16

what do immune cells have receptors for?

Answer 16

for antigens on microorganisms

Question 17

what can the antigens/ components of microorganisms recognised by immune cell receptors be?

Answer 17

cell wall components and virulence factors

Question 18

are receptors on immune cells unique for each antigen from different pathogens?

Answer 18

yes

Question 19

what are the main receptors on immune cells?

Answer 19

toll-like receptors

Question 20

how many toll-like receptors have been identified in humans?

Answer 20

10

Question 21

what do plasma membrane toll-like receptors recognise?

Answer 21

microorganisms that are external to the cell

Question 22

what do intracellular toll-like receptors recognise?

Answer 22

microorganisms that are invading the hose cell

Question 23

what toll-like receptors do we need to be aware of?

Answer 23

TLR-2, TL-4

Question 24

why do we need to know TLR-2 and TLR-4?

Answer 24

they recognise a variety of microorganism antigens

and they are found on a variety of innate immune cells

Question 25

what innate immune cells have the TLR-2?

Answer 25

monocytes, dendritic cells, mast cells, eosinophils, basophils

Question 26

what innate immune cells have the TLR-4?

Answer 26

macrophages, dendritic cells, mast cells, eosinophils

Question 27

aside from toll-like receptors, what other receptors are found on innate immune cells?

Answer 27

dectin and glucan receptors (fungal pathogens) NOD-like receptors (intracellular pathogens - viruses) protease-activated receptors (PARs) (allergens)

Question 28

what do dectin and glucan receptors recognise?

Answer 28

fungal pathogens

Question 29

what do NOD-like receptors recognise?

Answer 29

intracellular pathogens (viruses)

Question 30

what do protease-activated receptors (PARs) recognise?

Answer 30

allergens

Question 31

what is the collective term for the receptors on innate immune cells?

Answer 31

pattern recognition receptors (PRRs) that recognise pathogen associated molecular patterns (PAMPs)

Question 32

what is an example of an effector response by a host cell?

Answer 32

production of soluble mediators (protein release, chemical release) phagocytosis antigen presentation degranulation

Question 33

what are examples of soluble mediators produced by immune cells?

Answer 33

(focusing on 1-3) 1. antimicrobial peptides 2. enzymes (lysozyme and granzyme) 3. cytokines and chemokines 4. complement proteins 5. prostaglandins and leukotrienes 6. immunoglobulins (e.g., B cells) 7. growth factors 8. matrix metalloproteinases (MMPs)

Question 34

what are cytokines?

Answer 34

the hormones of the immune system - signalling molecules --> tell immune cells what to do

Question 35

are cytokines small or large proteins?

Answer 35

small (<80kDa in size)

Question 36

how are cytokines grouped?

Answer 36

into families by structure

Question 37

examples of the cytokine families?

Answer 37

interleukin family (e.g., IL-1beta, IL-6, IL-8) TNF family (e.g., TNF-alpha) interferons (e.g., IFN-gamma)

Question 38

are cytokines pro-inflammatory or anti-inflammatory?

Answer 38

some pro, some anti-inflammatory

Question 39

what are the different types of signals produced by cytokines?

Answer 39

autocrine paracrine endocrine

Question 40

what is autocrine signalling?

Answer 40

alter behaviour of cell which they were secreted e.g., self-regulating

Question 41

what is paracrine signalling?

Answer 41

alter behavior of neighboring cells

Question 42

what is endocrine signalling?

Answer 42

enter circulation and alter behavior of distant cells

Question 43

when would endocrine cytokines be produced by innate immune cells?

Answer 43

when immune cells at site of infection would produce endocrine cytokines to call for help from immune cells circulating in lymph and blood

Question 44

what do cytokine receptors recognise?

Answer 44

just cytokines

Question 45

what does cytokine binding induce?

Answer 45

conformational changes which results in signal transduction and leads to cellular effector response

Question 46

examples of effector responses from cytokine receptor activation?

Answer 46

similar as with microbial recognition: promote production of more cytokines and chemokines production of antimicrobial peptides production of growth factors production of receptors - to recognise more threats degranulation

Question 47

what are chemokines?

Answer 47

chemotactic cytokines (a type of cytokine)

Question 48

what is chemotaxis?

Answer 48

the movement of a cell in a direction corresponding to a gradient of increasing concentration of a substance

Question 49

what is the primary role of chemokines?

Answer 49

cell recruitment (directing and telling immune cells where to go)

Question 50

how do chemokines signal?

Answer 50

through chemokine receptors on immune cells (similar process to cytokines)

Question 51

what is the main example of a chemokine?

Answer 51

IL-8 (CXCL8) (has lots of functions in recruiting immune cells to site of where inciting cause is - site of infection)

Question 52

what are cytokines and chemokines vital for?

Answer 52

tissue homeostasis (e.g., following inflammation need anti-inflammatory cytokines to be produced)