immunology

Question 1

Why do we need an immune system?

Answer 1

defence against pathogens and defence against self (cancer)

Question 2

How can you be invaded?

Answer 2

through respiratory system, digestive system, urogenital tract or a break in the skin

Question 3

What are the routes of attack?

Answer 3

circulatory system and lymph system

Question 4

Why not live in a sterile environment?

Answer 4

you would have an impaired immune system

Question 5

What is the first line of defence?

Answer 5

skin, acid, bile mucus

Question 6

What is the second line of defence?

Answer 6

innate immune response

Question 7

What is the third line of defence?

Answer 7

adaptive immune system

Question 8

What is the chemical that damaged cells release?

Answer 8

histamine

Question 9

What does histamine do to blood vessels?

Answer 9

make them ‘leaky’

Question 10

What is innate immunity?

Answer 10

it is present before any response to pathogens and comprises barriers and chemical defences

Question 11

What occurs in the third line of defence?

Answer 11

antibody generation, specific proteins against specific targets

Question 12

What is adaptive immunity?

Answer 12

develops after exposure to microbes or toxins. it is the third line of defence

Question 13

What are the two main sites of development and maturation of immune cells?

Answer 13

in the bone marrow - production of Hematopoietic stem cells (HCSs). in thymus - T-lymphocyte maturation

Question 14

What organs are secondary lymphoid organs?

Answer 14

spleen, lymph nodes, mucosal associated lymphoid tissue (MALT)

Question 15

What is the main trigger for the immune response?

Answer 15

danger signals from damaged cells are the main trigger

Question 16

What is active immunity?

Answer 16

occurs naturally when a pathogen infects the body or can be induced when antigens are introduced into the body via vaccination

Question 17

What is passive immunity?

Answer 17

it is conferred naturally when antibodies cross from mother to foetus across placenta or can be conferred by artificially injecting antibodies into a non-immune individual

Question 18

What can disrupt the immune system?

Answer 18

allergy, autoimmune disease, latency, cancer

Question 19

What does the B stand for in B-lymphocyte?

Answer 19

Bursa of Fabricius

Question 20

What was the controversy surrounding Matzinger and Mirkwood?

Answer 20

In 1978 they (her and her dog) published a paper together in the Journal of Experimental Medicine

Question 21

What does innate immunity ultimately result in?

Answer 21

inflammation

Question 22

What is the goal of inflammation?

Answer 22

bring phagocytes to the injured area to isolate, destroy and inactivate invaders and to also remove debris and prepare subsequent healing

Question 23

What are neutrophils?

Answer 23

a blood phagocyte which is involved in oxygen related killing and express toll-like receptors

Question 24

What are macrophages/monocytes?

Answer 24

resident phagocyte which lasts for weeks - killing is nitrogen related and they express toll-like receptors and produce cytokines

Question 25

What do macrophages/monocytes do?

Answer 25

eat and clear bacteria and dead cells

Question 26

What are the four stages of phagocytosis?

Answer 26

attachment, internalisation, degradation, exocytosis

Question 27

What are NK cells?

Answer 27

they are lymphocyte-like with no immunological memory - they are very aggressive white blood cells

Question 28

What do NK cells require?

Answer 28

cell-cell contact to function

Question 29

How do NK cells kill?

Answer 29

via release of perforins, pores form in the cell membrane which results in cell lysis

Question 30

What do toll-like receptors recognise?

Answer 30

specific structures present on pathogens like peptidoglycan or viral/bacterial genetic material

Question 31

What does recognition by the toll-like receptors result in?

Answer 31

a signalling cascade and transcription factor activation. production of proteins required for cell signalling, interferons and pro-inflammatory cytokines

Question 32

How do cells in the immune system know where to go and what to do when they get there?

Answer 32

soluble communication factors called cytokines and chemokines

Question 33

What can the action of cytokines be?

Answer 33

autocrine, paracrine or endocrine

Question 34

What are cytokines produced by?

Answer 34

immune cells and connective tissue

Question 35

What does the name cytokine mean?

Answer 35

cell movement

Question 36

What the the chemokine receptors?

Answer 36

7 TMD and GPCR

Question 37

What does an interferon do?

Answer 37

interferes with viral replication, enhances phagocyte activity of macrophages, stimulates production of antibodies, enhances killing power of NK cells and cytotoxic T cells, slows cell division and tumour growth

Question 38

What are the three pathways of activation in the complement system?

Answer 38

classical, alternative + lectin

Question 39

What do the three pathways of activation in the complement system result in?

Answer 39

Membrane attack complex (MAC) formation and cell lysis

Question 40

What is the humoral defence?

Answer 40

antibodies made by B-lymphocytes which detect bacteria and viruses

Question 41

What are antigens?

Answer 41

toxin or diseased cell in body which acts as a flag to alert the adaptive immune system

Question 42

How many receptors are on the surface of a B-lymphocyte?

Answer 42

> 10,000

Question 43

What does each B cell have?

Answer 43

its own membrane bound receptor

Question 44

What are the functions of antibodies?

Answer 44

neutralisation, opsonisation, agglutination + phagocytosis, innate immune cell recruitment, activation of complement system, T-lymphocyte recruitment

Question 45

What happens in active immunity?

Answer 45

a dead or modified antigen is introduced, secondary response is harder and faster

Question 46

What happens after a phagocyte has engulfed a pathogen?

Answer 46

phagocytes that have engulfed a pathogen display part of the organism on proteins called MHCs on their surface - innate and adaptive cells can do this

Question 47

Where are T-lymphocytes made and where do they mature?

Answer 47

made in bone marrow, mature in thymus

Question 48

What are the two main classes of T-lymphocytes?

Answer 48

CD4 helper cells and CD8 cytotoxic cells

Question 49

What is the function of CD4 helper cells?

Answer 49

they activate other cells - they have receptors that identify the MHC2 and peptide, they then become activated and clone to helper and memory T cells and raise the alarm via cytokines which alerts other CD4s and activates CD8s

Question 50

What do T cells also activate?

Answer 50

they also 'finish' activation of B cells. If a CD4 cell binds to a B cell it releases cytokines and activates B cell leading to antibody production

Question 51

What do CD8 cytotoxic T cells do?

Answer 51

roam the body looking for diseased cells - they can bind to MHC1 and peptide - they release enzymes that punch holes in cells (perforin and granzymes) - also triggers apoptosis which kills the cell and pathogen inside

Question 52

What are regulatory T cells?

Answer 52

a subset of CD4 cells which release inhibiting cytokines that prevent adaptive immune system from producing too many antibodies or cytotoxic cells that can cause damage to self

Question 53

What are some autoimmune diseases?

Answer 53

diabetes, rheumatoid arthritis, multiple sclerosis

Question 54

What does HIV/AIDS do to T cells?

Answer 54

invades CD4 cells to reduce numbers