innate immunity

Question 1

what is the innate immune response?

Answer 1

first line of defence, no memory, present from birth, effective, non specific

Question 2

what compounds to epithelial barriers produce?

Answer 2

antimicrobial peptides, immunoglobulins, lactoferrin, lysozyme, cystatins

Question 3

what are antimicrobial peptides?

Answer 3

catatonic and amphipathic, attach and disrupt membranes eg human neutrophil peptides

Question 4

where is secretory IgA produced?

Answer 4

mucosal surfaces

Question 5

what does S-IgA do?

Answer 5

binds to flagella and 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 bacterial to mucosal surfaces

Question 6

what is lactoferrin?

Answer 6

Glycoprotein that transports iron ions but has antimicrobial activity, present in saliva, produced by neutrophils

Question 7

what is lysozyme?

Answer 7

present in saliva and produced by phagocytic cells, targets cell walls of bacteria

Question 8

what are cystatins?

Answer 8

anti-protease activity and supports re-mineralization of teeth

Question 9

what are antigens?

Answer 9

cells involved in immune response have receptors for components of microorganisms

Question 10

what are toxins and virulence factors?

Answer 10

microbial antigens

Question 11

what happens when a receptor is activated?

Answer 11

immune response begins

Question 12

give 2 examples of toll- like receptors

Answer 12

TLR-2 TLR-6heteridimer

TLR-4

Question 13

what are dectin and glucan receptors for?

Answer 13

fungal recognition

Question 14

what are NOD-like receptors for?

Answer 14

bacterial recognition

Question 15

what are protease-activated receptors for?

Answer 15

microbial and allergen recognition

Question 16

what are cytokines?

Answer 16

small proteins which signal molecules to co-ordinate immune responses

Question 17

what are the cytokine families?

Answer 17

interleukin, TNF, interferons, unassigned

Question 18

what is the autocrine function of cytokines?

Answer 18

alter behaviour of cell from which they were secreted

Question 19

what is the paracrine function of cytokines?

Answer 19

alter behaviour or neighbouring cells

Question 20

what is the endocrine function of cytokines?

Answer 20

enter circulation and alter behaviour of distant cells

Question 21

what does cytokine binding to receptors induce?

Answer 21

conformational change

Question 22

what are chemokines?

Answer 22

small signalling proteins- chemotactic cytokines

Question 23

what is chemotaxis?

Answer 23

movement of a cell in a direction corresponding to a gradient of increasing or decreasing concentration of a particular substance

Question 24

what is the main function of chemokines

Answer 24

recruitment (directing)

Question 25

what are the classes of chemokines?

Answer 25

C, CC, CXC, CX3C

Question 26

what do cell adhesion molecules control?

Answer 26

interactions between immune cells and endothelial cells

Question 27

what are the 3 main families of cellular adhesion molecules?

Answer 27

selectins, integrins, immunoglobulin superfamily

Question 28

what are neutrophils?

Answer 28

phagocytic granulocytes, most numerous cells in innate immune response, circulate in blood and move into tissue when required, contain numerous granules

Question 29

what is the primary function of neutrophils?

Answer 29

engulf and destroy invading pathogens

Question 30

what is degranulation?

Answer 30

granules in cells (vesicles) containing numerous antimicrobial peptides and enzymes are released upon activation of receptors

Question 31

what are neutrophil extracellular traps?

Answer 31

activation induces neutrophils to realease proteins and some genetic material to for extra-cellular fibril matrix, trap pathogens

Question 32

what are monocytes?

Answer 32

precursors to macrophages which circulate in blood-differentiate into macrophages in tissues

Question 33

what is the role of macrophages?

Answer 33

early responders to infection or tissue damage, long lived, phagocytose and present antigen

Question 34

what other innate immune cells are at oral mucosa?

Answer 34

NKC, innate lymphoid cells, mast cells, dendritic cells, eosinophils and basophils

Question 35

what are the 3 stages of phagocytosis?

Answer 35

degradation and removal of pathogenic threat, antigen presentation, safely break down and dispose of apoptotic cells

Question 36

what are the 2 types of antigen presenting cell?

Answer 36

non-professional- epithelial, fibroblasts, endothelial cells

professional- macrophages and dendritic cells

Question 37

what are the 6 stages of phagocytosis?

Answer 37

1. chemotaxis + adherence of miscrobe to phagocyte
2. ingestion of microbe by phagocyte
3. formation of phagosome
4. fusion of phagosome with lysosome to form phagolysosome
5. digestion of ingested microbe by enzymes
6. discharge of waste materials

Question 38

what does plasma contain?

Answer 38

water, salts, antibodies and other proteins

Question 39

what are the 4 enzymatic cascade systems in plasma?

Answer 39

complement
kinins
coagulation factors
fibrinolytic system

Question 40

what is complement?

Answer 40

a collection of soluble proteins present in circulation, drives inflammation/opsonisation-coating of pathogens by antibodies/complement proteins

Question 41

what are the 3 complement pathways?

Answer 41

classical-antibody attached to microbe
alternative-microbial cell wall
mannose binding lectin (MBL) -carb on pathogen surface

Question 42

what are anaphylatoxins?

Answer 42

glycoproteins such as complement proteins C3, C4, C5 that drive immune responses

Question 43

what are the functions of anaphylatoxins?

Answer 43

promote immune cell recruitment
increase adhesion of cells to vessel walls
induces granulation
promotes cytokine production
induces antigen presentation
regulate adaptive immune response