Innate immunity 1

Question 1

Examples of inciting causes

Answer 1

invading microorganisms, particulate materials (allergens, prostheses), altered self cells (growth disorders/cell injury), transformed malignant cells (neoplasia)

Question 2

What is inflammation?

Answer 2

an immune response aimed at eliminating the inciting cause

Question 3

4 stages of inflammation

Answer 3

initiation (response to harmful agents), progression (containment of agent), amplification (modulation of immune response), resolution (healing or failure to resolve)

Question 4

What is acute inflammation?

Answer 4

Inflamed tissue that can heal itself (e.g. gingivitis)

Question 5

What is chronic inflammation?

Answer 5

inflammation that cannot be resolved - e.g. periodontitis (alveolar recession)

Question 6

What is innate immunity?

Answer 6

an effective, first line of non-specific immunological defence against an inciting cause

Question 7

Which cells are involved in innate immunity?

Answer 7

Innate immune cells (leucocytes), and non-professional immune cells

Question 8

Mechanisms of action of innate immune cells

Answer 8

phagocytosis, degranulation, antigen presentation, mediator release

Question 9

what are the 4 types of epithelium in the oral cavity?

Answer 9

lining/buccal mucosa, masticatory epithelia, gustatory mucosa, crevicular/junctional epithelia

Question 10

Function of the epithelium

Answer 10

structural, mechanical and immunological support

Question 11

What are the compounds produced by epithelial barriers?

Answer 11

Antimicrobial peptides, secretory IgA, lactoferrin, lysozyme, cystatins

Question 12

Where are the compounds produced by epithelial barriers found?

Answer 12

In oral secretions (saliva, gingival crevicular fluid - GCF)

Question 13

Which of the 5 types of antibodies are produced by the epithelium?

Answer 13

Secretory IgA (produced by B cells)

Question 14

What is the main type of antimicrobial peptide (AMP) produced by the epithelium?

Answer 14

Cathelicidins (e.g. LL-37)

Question 15

Function of cathelicidins

Answer 15

attach and disrupt microbial membranes causing lysis

Question 16

What is the structure of IgA?

Answer 16

double headed with 4 antibody binding sites

Question 17

What is lysozyme?

Answer 17

an enzyme found in saliva that targets components of bacterial cells walls (e.g. peptidoglycan) causing lysis

Question 18

Name of peptide cell wall components/virulence factors that immune cell receptors bind to

Answer 18

antigens

Question 19

Main receptors for microbial recognition

Answer 19

toll-like receptors

Question 20

Where can toll-like receptors be located?

Answer 20

on plasma membrane to recognise external microorganism, on organelles to recognise intracellular/invading pathogens (e.g. viruses)

Question 21

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

Answer 21

10

Question 22

What are the types of receptors on immune cells?

Answer 22

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

Question 23

What do dectin and glucan receptors recognise?

Answer 23

Fungal pathogens

Question 24

What do NOD-like receptors recognise?

Answer 24

intracellular pathogens (viruses)

Question 25

What do protease-activated receptors (PARs) detect?

Answer 25

allergens (non-microbial)

Question 26

What are the receptors that recognise unique components of microbes (PAMP) collectively known as?

Answer 26

Pattern Recognition Receptors (PRRs)

Question 27

What are PAMPs?

Answer 27

Pathogen associated molecular patterns are unique components of microbes e.g. lipopolysaccharide

Question 28

What happens when a receptor detects a PAMP (microbial recognition)?

Answer 28

Microbial recognition -> cell activation -> effector response

Question 29

Examples of cellular responses (depends on cell type)

Answer 29

production of soluble mediators (protein/chemical release e.g. cytokines), phagocytosis, antigen presentation, degranulation

Question 30

Examples of soluble mediators produced by immune cells

Answer 30

antimicrobial peptides, enzymes (e.g. lysozyme, granzyme), cytokines, chemokines, immunoglobulins (B cells)

Question 31

What are cytokines?

Answer 31

small proteins that are soluble mediators produced by immune cells in response to microbial recognition.

Question 32

Function of cytokines

Answer 32

signalling molecules that coordinate immune responses. Either anti-inflammatory or pro-inflammatory (dampen/drive inflammation)

Question 33

How are cytokines grouped?

Answer 33

Grouped into families by structure (e.g. interleukin family, TNF family, Interferons)

Question 34

3 types of cytokines (depending on target cell)

Answer 34

autocrine, paracrine, endocrine

Question 35

What are autocrine cytokines?

Answer 35

Cytokines that alter behaviour of the cell they are secreted from e.g. self-regulating

Question 36

What are paracrine cytokines?

Answer 36

Cytokines that alter behaviour of neighbouring cells

Question 37

What are endocrine cytokines?

Answer 37

Cytokines that enter the circulation and alter behaviour of distant cells

Question 38

How are cytokines detected by target cells?

Answer 38

Via cytokine receptors (not microbial / PRRs receptors)

Question 39

What happens when cytokines bind to target immune cells?

Answer 39

Signal transduction occurs resulting in effector responses similar to microbial recognition responses

Question 40

What are the potential cellular responses as a result of cytokines binding?

Answer 40

Increased production of cytokines, chemokines, antimicrobial peptides, growth factors, receptors and degranulation

Question 41

What are chemokines?

Answer 41

Chemotactic cytokines (proteins) that are involved in immune cell recruitment/trafficking

Question 42

What is chemotaxis?

Answer 42

The movement of a cell in a direction corresponding to a gradient of increasing concentration of a substance (e.g. immune cell moving towards an increasing concentration of chemokines).

Question 43

How are chemokines detected by target cells?

Answer 43

Via chemokine receptors on immune cells

Question 44

Out of all the different classes of chemokines, which is the main example?

Answer 44

IL-8 (CXCL8)

Question 45

Function of chemokines and cytokines

Answer 45

tissue homeostasis - promote balance between pro-inflammatory and anti-inflammatory

Question 46

Consequences of an immune over-reaction

Answer 46

autoimmune problem (internal threat), allergic reaction (external threat)

Question 47

Consequences of an immune under-reaction

Answer 47

cancer, infection