immunology

Question 1

what are 5 main components of the innate immune system

Answer 1

mechanical barriers
physiological - stomahc acid, fever etc
chemical mediators
phagocytic leukocytes
natural killer cells

Question 2

what are the main points of the innate immune system?

Answer 2

first line of defence
produce local redness and swelling associated
non-specific response

Question 3

what are the 3 pathways of complement activation?

Answer 3

classical, lectin or mannose binding pathway and alternative pathway

Question 4

what is different about the mannose binding pathway?

Answer 4

involves manose bidning lectin which binds sugars on the surface of proteins to MASP 1 and 2

Question 5

what is different about the alternative pathway?

Answer 5

it has autoactivation of C3 when in contact with bacteria

Question 6

what does the complement do to help fight of pathogens

Answer 6

produce MAC to stab invading pathogens
produce anaphylatoxins
opsinisation of pathogens for phagocytosis by macrophages and neutrophils
attract neutrophils to the site of infection - complement products of C5a

Question 7

what is the role of phagocytes in the immune system?

Answer 7

include macrophages, dendritic cells and neutrophils
they engulf pathogens by phagocytosis and express MHC II (macrophages) to make APC
secrete interleukin 1 and tumour necrosis factor (TNF)

Question 8

what do neutrophils do in the immune system?

Answer 8

reside in the blood
activated and attracted to the site of infection
they have a double mechanism to bind to the blood vessel

neutrophils attack F-met peptides and once activated become phagocytotic and produce TNF

Question 9

what do natural killer cells do in the immune system?

Answer 9

produce cytokines

destroy infected cells - uses fas ligand to bind to fas on target cell inducing apoptosis

Question 10

where are B cells made?

Answer 10

derived from pluripotent hematopoietic stem cells in the bone marrow

lymphoid lineage

mature in lymph nodes

Question 11

where are T cells made?

Answer 11

derived from pluripotent hematopoietic stem cells in the bone marrow

lymphoid lineage

mature in the thymus

Question 12

how are B cells activated?

Answer 12

binding of antigen to receptors on the cell surface which causes the cell to divide and proliferate
a second signal is often needed

Question 13

what is the main roles of B cells?

Answer 13

antibody production
activation of Tcells
activation of innate immunity

Question 14

how are T cells activated?

Answer 14

antigen presented with MHC class I or II and CD80

Question 15

what is the function of T cells?

Answer 15

release cytokines

Question 16

what do cytokines do?

Answer 16

chemoattraction
autoactviation
augmentation of inflammation
stimulation of Ab production by B cells
activate macrophages

Question 17

what is the role of BCR?

Answer 17

transduction and mediating internalization

Question 18

what is the role of TCR?

Answer 18

responsible for recognising fragments of antigen as peptides bound to MHC

Question 19

what is the role of CD4?

Answer 19

receptors on T helper cells that bind to MHCII

Question 20

what is the role of CD8?

Answer 20

receptors on T cytotoxic cells that bind to MHCI

Question 21

what is the role of CD28?

Answer 21

expressed on T cells, provide co-stimulatory signals required for T cell activation

Question 22

what is the role of CD80?

Answer 22

co stimulatory molecule for T cell activation

Question 23

What is the role of T cytotoxic cells?

Answer 23

have CD8 receptors which recognise MHC I

they destory cells by releasing enzymes which distrupt the cell membrane

Question 24

what is the role of T helper cells?

Answer 24

have CD4 receptors which redcognise MHC II
activate B cells
activate phagocytes
produce Th1 and Th2 cytokines - they augment cell mediated and humoral immunity

Question 25

what is the role of MHC I?

Answer 25

present endogenous antigens synthesised int he cytoplasm | display on surface membrane to CD8 receptors on cytotoxic cells

Question 26

what is the role of MHC II?

Answer 26

Present exogenous antigens from extracellular material | displays antigen to CD4 receptors on t helper cells

Question 27

what antibody types are monomers?

Answer 27

IgG, IgE and IgD

Question 28

what does IgG do?

Answer 28

neutralises toxins opsinisation main Ig in the blood

Question 29

what does IgE do?

Answer 29

antibody of allergy and antiparasitic activity

Question 30

what does IgM do?

Answer 30

main antibody of primary responses | good opsiniser

Question 31

what does I gA do?

Answer 31

secreted into mucus, tears and saliva preventing entrance of pathogens

Question 32

what does IgD do?

Answer 32

found on B cell membrane | helps cell division

Question 33

what type of antibody is a dimer?

Answer 33

IgA

Question 34

what type of antibody is a pentamer?

Answer 34

IgM

Question 35

how does immune memory work?

Answer 35

B cells remember antigen and when confronted a second time with the same antigen the ab response in much quicker

Question 36

how does vaccination work?

Answer 36

relies on introduction of pathogenic source immune response develops and provides long lasting immunity booster injection may be needed

Question 37

What is antibody switching?

Answer 37

immature B cells produce IgD and IgM when activated B cells switch Ig class depending on location and function

Question 38

how is diveristy of antibodies generated?

Answer 38

``` the variable region of the antibody made up of the building blocks: V (varible) gene D (diveristy) gene J (joining) gene somatic mutations changes affinity ```

Question 39

what is autoimmunity?

Answer 39

missdirected adaptive immune repsonse = loss of self tolerance hypersensitivity reactions = over reaction of adpative immuen response immunodeficiencies = components of immuen system are absent or defective

Question 40

what is clonal deletion, during the development of B or T cells?

Answer 40

if developing B or T cells recognise self antigen they will be triggered to die, so this clone of cells is deleted

Question 41

during T cell activation, which moleucles on the T cell recognise the Ag/MHC complex and 2nd signall on the antigen presenting cell?

Answer 41

T cell receptor (CD4 or CD8) recognise Ag/MHC and CD28 recognises the 2nd signal - CD80

Question 42

what are the 3 main types of T cell?

Answer 42

cytotoxic T cell T helper cell Regulatory T cell

Question 43

which antibdy class is common on mucosal surfaces such as in the GI tract and respiratory tract?

Answer 43

IgA

Question 44

what molecule that is expressed on endothelial cells in repsonse to cytokines released by hperactive macrophages binds to a ligand on the surface of neurophils

Answer 44

selectin

Question 45

which cytokines are released by hyperactive macrophages?

Answer 45

TNF and IL-1

Question 46

what is required to stimulate primed macrophages to become hyperactive?

Answer 46

IFN-y and LPS (lipopolysaccharide from gran negative bacteria)

Question 47

what is the difference between resting and primed macrophages?

Answer 47

primed macrophages express more MHC class II and take up larger objects by phagocytosis

Question 48

where would you expect to find iC3b?

Answer 48

on the surface of a bacterial cell

Question 49

oligmers of which protein form the pore through bacterial membranes as part of the membrane attack complex

Answer 49

C9

Question 50

which pathway is activated by the sugars on pathogens such as bacteria, yeast and certain parasites?

Answer 50

lectin or mannose binding pathway

Question 51

autoactivation of which complement protein is involved in the alternative pathway of complement activation

Answer 51

C3

Question 52

viral peptides are loaded onto.......

Answer 52

MHC class I molecules