Innate Immunity 2

Question 1

what are cytokines?

Answer 1

small proteins that act as signalling molecules to co-ordinate immune responses

Question 2

what are chemokines?

Answer 2

small proteins that are involved in directing cells to the site of infection

Question 3

give an example of a cell that is both chemokine and cytokine

Answer 3

IL-8 / CXCL8

Question 4

what is the most abundant cell type at the oral mucosa?

Answer 4

neutrophils

Question 5

what do neutrophils do during inflammation?

Answer 5

they increase in number and they are attracted along a CXCL8 gradient to the site of inflammation

Question 6

what do cell adhesion molecules do?

Answer 6

control interactions between immune cells and endothelial cells

Question 7

what are the three main families of cell adhesion molecules?

Answer 7

selectins, integrins and immunoglobulin superfamily

Question 8

what do cell adhesion molecules promote and what are they important for?

Answer 8

promote cell-cell interactions and are important for immune trafficking

Question 9

what are endothelial cells?

Answer 9

cells that line the interior surface of blood vessels and lymphatic vessels

Question 10

where are selectins and immunoglobins found?

Answer 10

on endothelial cells

Question 11

where are integrins found?

Answer 11

on migrating immune cells

Question 12

what is the primary funciton of neutrophils?

Answer 12

to engulf and destroy invading pathogens

Question 13

what do granules contain?

Answer 13

degradative enzymes and antimicrobial substances

Question 14

what is degranulation?

Answer 14

when the granules are released upon activation of receptors

Question 15

what happens when neutrophils are activated?

Answer 15

it induces them to release proteins and some genetic material (chromatin) to form extra-cellular fibril matrix which TRAPS PATHOGENS

Question 16

what do monocytes do?

Answer 16

circulate in the blood as precursors to macrophages

Question 17

what is the primary function of macrophages?

Answer 17

phagocytosis as well as presentation of antigen to adaptive immune cells

Question 18

what is the function of mast cells?

Answer 18

degranulation

Question 19

what is the function of dendritic cells?

Answer 19

present antigen to T cells

Question 20

what cells contain granules?

Answer 20

mast cells, natural killer cells, monocytes, macrophages and neutrophils

Question 21

what are granules?

Answer 21

vesicles containing preformed mediators

Question 22

what preformed mediators are contained within granules?

Answer 22

proteinases, antimicrobials, chemical mediators

Question 23

what are the preformed mediators in the granules in response to?

Answer 23

MAMPs (e.g. microbial antigens), complement proteins, cytokines and other inflammatory mediators

Question 24

what is phagocytosis?

Answer 24

degradation and removal of pathogenic threat, antigen presentation, safe break down and disposal of apoptotic cells

Question 25

what are the 2 types of antigen presenting cells?

Answer 25

non-professional and professional

Question 26

give an example of a non-professional APC

Answer 26

epithelial cells/fibroblasts/endothelial cells

Question 27

give an example of professional APCs

Answer 27

macrophages and dendritic cells

Question 28

what is the first step of phagocytosis?

Answer 28

CHEMOTAXIS and adherence of microbe to phagocyte

Question 29

what is the second step of phagocytosis?

Answer 29

INGESTION of microbe by phagocyte

Question 30

what is the third step of phagocytosis?

Answer 30

FORMATION of a phagosome

Question 31

what is the fourth step of phagocytosis?

Answer 31

FUSION of the phagosome with a lysosome to form a phagolysosome

Question 32

what is the fifth step of phagocytosis?

Answer 32

DIGESTION of ingested microbe by enzymes

Question 33

what is the sixth step of phagocytosis?

Answer 33

formation of RESIDUAL BODY containing indigestible material

Question 34

what is the seventh step of phagocytosis?

Answer 34

DISCHARGE of waste materials

Question 35

what happens to the degraded waste material in non-APCs

Answer 35

released and sometimes picked up by APCs

Question 36

what happens to the degraded waste material in APCs?

Answer 36

it is processed for antigen presentation

Question 37

what is the first step of antigen presentation?

Answer 37

a pathogen or extracellular antigen s phagocytised by an APC and placed into a vesicle. Ingested pathogens are digested by lysosomes to extract their antigens

Question 38

what is the second step of antigen presentation?

Answer 38

the antigens bind with MHC proteins that enter the vesicle

Question 39

what is an MHC protein?

Answer 39

major histocompatibility complex

Question 40

what is the third step of antigen presentation?

Answer 40

the MHC proteins, now carrying antigens, are released from the vesicle and travel to the outer surface of the cell membrane

Question 41

what is the fourth step of antigen presentation?

Answer 41

the APC cell is now presenting antigens which will activate T cells that bind with the MHC proteins

Question 42

what are the 4 enzymatic cascade systems of plasma factors?

Answer 42

complement, kinins, coagulation factors, fibrinolytic system

Question 43

what do the 4 enzymatic cascades produce?

Answer 43

inflammatory mediators

Question 44

what is complement?

Answer 44

a collection of soluble proteins present in circulation

Question 45

what does complement do?

Answer 45

drives inflammation or opsonisation

Question 46

what is opsonisaion?

Answer 46

the coating of pathogens by antibodies or complement proteins

Question 47

what are the 3 pathways of complement?

Answer 47

classical, alternative and lectin

Question 48

what is the initiating factor of the classical pathway of complement?

Answer 48

antibody attached to microbe

Question 49

what is the initiating factor of the alternative pathway of complement?

Answer 49

microbial cell wall

Question 50

what is the initiating factor of the lectin pathway of complement?

Answer 50

carbohydrates on pathogen surface

Question 51

what do anaphylatoxins lead to?

Answer 51

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

Question 52

what do all the complement pathways lead to?

Answer 52

the formation of C3 and C5 convertase enzymes

Question 53

what are the steps of complement?

Answer 53

binding of complement proteins to microbial cell surface or antibody - formation of C3 convertase - cleavage of C3 - formation of C5 convertase

Question 54

what do C3 and C5 convertase enzymes do?

Answer 54

degrade C3 or C5 proteins

Question 55

what are anaphylatoxins?

Answer 55

glycoproteins such as complement components C3, C4 and C5 (and their fragments) that drive immune response

Question 56

what do anaphylatoxins do?

Answer 56

promote immune cell recruitment, increase adhesion of cells to vessel walls, induces granulation, promotes cytokine production, induces antigen presentation and regulates adaptive immune responses

Question 57

how to neutrophils, monocytes and other immune cells migrate to site of infection?

Answer 57

via cell surface receptors on endothelial cells (selectins, integrins and immunoglobulin superfamily)

Question 58

what are the three main process involved in innate immunity?

Answer 58

degranulation, phagocytosis and antigen presentation

Question 59

why is complement important?

Answer 59

for innate and adaptive immune responses