L28 Immune System Influence on Homeostasis

Question 1

where do most immune cells originate?

Answer 1

bone marrow

Question 2

what is the fate of b-cells?

Answer 2

stay in bone marrow and later form plasma cells that are capable of making antibodies

Question 3

how does the lymphatic system help immune system?

Answer 3

gather and present foreign antigens to immune cells - increased adaptative responses to disease/ decreased suceptibility

Question 4

what immune cells are part of the innate immune system?

Answer 4

dendritic, macrophage, natural killer cell NKC

Question 5

what immune cells are part of the adaptive immune system?

Answer 5

B and T cells

Question 6

what are innate immune cells?

Answer 6

rapidly expressed immune cells - recognise continuously recurring surface materials of pathogens

Question 7

what are adaptive immune cells?

Answer 7

cells that are expressed only when present with antigens by innate cells

Question 8

which immune system is slower forming and why?

Answer 8

adaptive immune system because it is specialised

Question 9

what is a balanced immune system?

Answer 9

this is when immune cells have optimum effectiveness - they defeat pathogen as best they can without harming body cells

Question 10

what happens in an immune under-reaction?

Answer 10

disease (cancer) and infection (bacteria) can override the system and take over body cells

Question 11

what happens in an immune over-reaction to an internal threat?

Answer 11

auto immune problem example IBD, Type 1 diabetes

Question 12

what happens in an immune response over reaction to an external threat?

Answer 12

an allergic reaction example eczema, food sensitivities

Question 13

how does the body maintain a balanced immune system?

Answer 13

monitoring via homeostasis

Question 14

what cells trigger and regulate immune responses?

Answer 14

cytokines

Question 15

what happens if pathoegns override immune system?

Answer 15

progressive inflammation of cells

Question 16

what are exogensis antigens?

Answer 16

antigens that enter from outside the body such as bacteria and fungi - not all are bad

Question 17

apart from fighting infection, what role does the immune system play in the body?

Answer 17

maintaining homeostasis

Question 18

how are viruses recognised?

Answer 18

nucleic acid detection

Question 19

what are interferons?

Answer 19

protein signals that are induced when RNA viruses enter cell - they interfere with viral infection cycle

Question 20

where are interferons released?

Answer 20

from infected cells to local cells

Question 21

what is the purpose of interferon induction?

Answer 21

to signal the infection to neighbouring cells and initiate an immune response

Question 22

describe the pathway of RNA virus detection

Answer 22

1) RNA Virus enters cell
2) infected cells induce interferons
3) local cells turn on signalling pathways to produce STAT proteins
4) Different genes are turned on to prevent adsorption of virus onto cell surface and prevent mRNA transcription

Question 23

how do viruses block attacks from IFNs?

Answer 23

mutation and evolution

Question 24

what is the virus cycle?

Answer 24

1) adsorption
2) entry
3) uncoating
4) mRNA transcription
5) translation
6) genome replication
7) packaging

Question 25

what happens if virus outcompetes interferons?

Answer 25

the innate immune system stimulates a chemotaxis response

Question 26

what is chemotaxis?

Answer 26

Cells detect the direction and intensity of an extracellular chemical gradient, and migrate toward the source of stimulus - in this case it is towards infectious agent

Question 27

what happens when there is an immune/ chemotaxic response in lung tissue?

Answer 27

inflammation - impaired breathing can lead to hypoxia, no oxygen to brain leads to tissue death and damage

Question 28

what is hypoxia?

Answer 28

failure of delivering oxygen to tissues causes them to die - low oxygen levels in body

Question 29

what are 4 examples of where immune system is involved in homeostasis?

Answer 29

invasion of viruses, cancer growth, fat interactions and brain health

Question 30

how do NKC fight cancer cells?

Answer 30

secrete granzyme into tumour pore - digesting the tumour

Question 31

how do t-cells become activated in repsonse to cancer?

Answer 31

1) APC presents specific antigen to naive T-cell 2) APC uses MHC to present antigen protein to T-cell receptor 3) Naive T-cell is partially activated 4) B7 protein on APC binds with CD28 of T-cell 5) cytokines are released - fully activated

Question 32

How are T-cells fully activated in response to cancer?

Answer 32

1) APC'S MHC receptor presents protein to T-cell receptor (TCR) 2) B7 on APC binds with CD28 of T-cell 3) cytokine production

Question 33

what is MHC?

Answer 33

major histocompatibility complex (MHC), group of genes that code for proteins found on the surfaces of cells that help the immune system recognize foreign substances

Question 34

what is APC?

Answer 34

antigen presenting cells

Question 35

what is pro-inflammatory?

Answer 35

cytokines promote inflammation of cells

Question 36

what prevents B7(APC) and CD28(T-Cell) interactions?

Answer 36

CTLA4 and PD1

Question 37

what happens CTL4 and PD1 prevent B7 and CD28 interactions?

Answer 37

T-cell population is suppressed - cancer cells grow uncontrollably

Question 38

how are cells less likely to bind with CTL4 over CD28?

Answer 38

antibody introduction, CTL4 binds with antibody instead

Question 39

What 2 checkpoints are important in recognising and destroying tumour cells?

Answer 39

1) ipilimumab antibiotic targets CTLA4 | 2) nivolumab antibiotic targers PD1

Question 40

What does nivolumab target?

Answer 40

PD1

Question 41

what does ipilimumab target?

Answer 41

CTLA4

Question 42

What advantages do CTLA4 and PD1 have?

Answer 42

they prevent excessive responses of the immune system - somewhat regulation

Question 43

where is the immune system unexpectedly active?

Answer 43

brain and adipose tissue

Question 44

what happens adipose immune population when fat globules form?

Answer 44

they die - this is due to obesity

Question 45

An immune response in tissue causes inflammation what can this cause?

Answer 45

insulin resistance leading to diabetes type 2

Question 46

what happens NKT cells during obesity?

Answer 46

they deplete

Question 47

what do NKT produce?

Answer 47

anti-inflammatory cytokine IL10

Question 48

What happens as a result from NKT depletion?

Answer 48

pro-inflammatory state and obesity

Question 49

what molecule does NKT depend on?

Answer 49

CD1d to present antigens

Question 50

what are NKT cells regulators of?

Answer 50

adipocyte and lipid metabolism, insulin sensitivity

Question 51

what immune cells are found in brain?

Answer 51

microglia macrophages

Question 52

when do microglia macrophages become activated?

Answer 52

plaque deposition during Alzheimer's

Question 53

what helps the removal of amyloid plaques?

Answer 53

proteins in meningeal membranes

Question 54

why is the brain bad at detecting antigens?

Answer 54

we do not know

Question 55

2 hit hypothesis

Answer 55

vulernable to a second stimulus after first stimulus - infection and brian injury