Immunology

Question 1

What cell is associated with the innate immune response?

Answer 1

neutrophils.

Question 2

What are the tissue resident innate immune cells?

Answer 2

macrophages, mast cells, NK cells, dendtritic cells.

Question 3

Which cell kills virally infected and cancer cells?

Answer 3

NK cells.

Question 4

Which cells mediate the allergic response

Answer 4

eosniphils.

Question 5

Which cells play a key role in the defence against parasites?

Answer 5

mast cells.

Question 6

How do macrophages kill?

Answer 6

phagolysosome and toxic reactive oxygen and nitrogen species.

Question 7

What do pathogens express and how do innate immune cells recognise these?

Answer 7

pathogen: PAMPs (pathogen associated molecular pattern)

immune cell: PRRs (pathogen recognition receptors)

Question 8

What is the acute phase response?

Answer 8

a change in plasma concentration of specific proteins in response to inflammation.

Question 9

What plasma proteins are involved in the acute phase response?

Answer 9

CRP (acts as opsonin)
manganese superoxidase
fibrinogen

Question 10

what are the cell adhesion molecules that neutrophils bind to?

Answer 10

selectins

ICAM1/VCAM1

Question 11

what is involved with selectins and neutrophils?

Answer 11

neutrophils bind weakly to selectins via integrins. selectin mediated rolling of neutrophils occur.

Question 12

what is involved with ICAM1/VCAM1 and neutrophils?

Answer 12

neutrophils bind strongly to ICAM1/VCAM1 via integrins. DIAPEDISIS occurs (squeeze through endothelial cells)

Question 13

How do neutrophils kill?

Answer 13

release of Anti-microbial proteins. produce toxic reactive oxygen species. release NETs (neutrophil extracellular traps - act as opsonins)

Question 14

What is the complement system?

Answer 14

a family of proteins produced by the liver. potent enzymatic cascade and amplification loop.

Question 15

how is the complement system activated?

Answer 15

1) classic complement pathway: antibodies (IgG, IgM) binding to antigens
2) alternative complement pathway: C3b
3) Lectin pathway

Question 16

which protein forms the membrane attack complex? how does it kill?

Answer 16

C5b. osmotic lysis.

Question 17

Which complement protein is a key mediatiator in the complement system and also acts as an opsonin?

Answer 17

C3

Question 18

What is the function of B-cells?

Answer 18

produce antibodies (plasma cells)
produce memory B-cells

Question 19

what do CD4+ T-cells do? CD8+ T-cells?

Answer 19

CD4+ = Helper T-cells. Key regulators of the adaptive immune response, help activate other cells.
CD8+ = Cytotoxic T-cells. kill virally infected cells.

Question 20

How do CD8+ cells kill?

Answer 20

1) Fas

2) release of perforin (both activate caspases)

Question 21

Which gene codes for antibodies and how is variation achieved?

Answer 21

segmented genes. random rearrangement of the segemnted genes.

Question 22

What constitutes the primary lymphoid tissue?

Answer 22

bone marrow: site of all leukocyte development

Thymus: site of T-cell maturation

Question 23

What tissue is secondary lymphoid tissue?

Answer 23

lymph nodes + spleen

Question 24

How does an antibody bind to an antigen?

Answer 24

via Fab —> epitope (on antigen)

Question 25

what is a dendritic cell? how does it do this?

Answer 25

professional antigen presenting cells. express antigen specific peptides on MHC moleculs

Question 26

in the secondary lymphoid tissue, which cells are found in "B-cell zones"?

Answer 26

Stromal cells. "trap" opsonised antigens

Question 27

what are the 2 types of MHC molecules? where are they found and who do they present to?

Answer 27

``` class I MHC: expressed on all nucleated cells. present antigen to cytotoxic T-cells (CD8+) class II MHC: expressed only on antigen presenting cells (dendritic, macrophages, B-cells). present antigen to CD4+ helper T-Cells ```

Question 28

What is the germinal centre and where is found?

Answer 28

found in secondary lymphoid tissue. site of B-cell proliferation and differentiation

Question 29

describe IgG

Answer 29

most abundant immunoglobulin in plasma. pass through placenta, providing protection to babies.

Question 30

describe IgM

Answer 30

largest of the antibodies. 1st antibody produced in infection.

Question 31

describe IgA

Answer 31

responsible for mucosal immunity.

Question 32

describe IgE

Answer 32

responsible for the allergic response.

Question 33

What are Peyer's patches? where are they found?

Answer 33

organised lymphoid tissue. found in the ileum.

Question 34

What special epithelial cell lines Peyer's patches?

Answer 34

M cells (have a characteristic membrane ruffle)

Question 35

what is the IELs found in epithelium called?

Answer 35

(intra-epithelial lymphocytes) CD8+ cytotoxic T-cells

Question 36

What is selective IgA deficiency associated with?

Answer 36

coeliac disease.

Question 37

what is type 1 hypersensitivity?

Answer 37

immediate hypersensitivity (allergy). IgE mediated.

Question 38

what is type 2 hypersensitivity?

Answer 38

direct cell killing/cytotoxic hypersensitivity. this is achieved via activation of the complement system (classical pathway only: IgG/M-->antigen) forming the membrane attack complex (C5b). eg. ABO blood incompatibility

Question 39

what is type 3 hypersensitivity

Answer 39

immune-complex mediated. eg. farmers lung, bird fanciers lung

Question 40

what is type 4 hypersensitivity?

Answer 40

delayed type hypersensitivity. (T-cell mediated). non-caseating granuloma formation. eg. TB, sarcoidosis, Rheumatoid arthritis.