Haematopoiesis (and Immune System Overview)

Question 1

What is immunology?

Answer 1

a branch of biochemical / biomedical science that is concerned with
the molecular, cellular and biochemical processes involved with how
the body defends itself against disease

Question 2

What do immunological processes protect?

Answer 2

Immunological processes protect / defend our bodies against infectious
disease as well as non-communicable diseases such as cancer

Question 3

What do immune cells recognise?

Answer 3

recognise ‘self’ from ‘non-self’ or ‘altered-self’.

Question 4

Receptors on the surface of immune cell membranes recognise what?

Answer 4

protein markers of ‘self’

Question 5

Self-reactive immune cells are weeded out
through …

Answer 5

… positive selection during lymphocyte
maturation

Question 6

Pathogen associated molecular patterns
(PAMPs) are …

Answer 6

… ‘non-self’ molecules

Question 7

What are PAMPS?

Answer 7

Pathogen associated molecular patterns

Question 8

what recognises PAMPs?

Answer 8

Immune cell receptors
such as, toll-like receptor
(TLR), recognise PAMPs

Question 9

Whats MHC?

Answer 9

Major Histocapability Complex (MHC)

Question 10

What do PAMPs include ?

Answer 10

lipopolysaccharide (LPS), lipoteichoic acid, flagellin,
peptidoglycan (bacteria) and dsRNA (viruses)

Question 11

Innate immunity can be…

Answer 11

… cellular or not

Question 12

What components of the innate immune system are NOT cellular?

Answer 12

Physical barrier
Skin
Mucosa
Sebaceous glands
Goblet cells

Question 13

What is the purpose of physical barriers?

Answer 13

purpose to keep foreign invaders out

Question 14

14

Question 15

What is the function of lysosymes?

Answer 15

hydrolyses NAG-NAM
glyosidic bonds (gram +ve bacteria)

Question 16

whats Human B1-defensin?

Answer 16

a poly-peptide with positively charged and
hydrophobic regions, that creates pores in the membrane

Question 17

What is Human B1-defensin secreted by?

Answer 17

epithelial cells

Question 18

What are complement proteins?

Answer 18

plasma pro-proteins that are activated in a
cascade creating the membrane attack complex

Question 19

What are the innate immune cells?

Answer 19

Neutrophil
Eosinophil
Basophil
Monocyte

Question 20

Innate immune cells are activated against what?

Answer 20

Innate immune cells are activated against
‘non-self’ antigen
non-specifically via
PAMP recognition

Question 21

What are granulocytes?

Answer 21

cytosolic granules, multi-lobed or bi-lobed nuclei

contain granules which kill cells in response to receptor activation.

Question 22

18

Question 23

What percentage of all leukocytes are neutrophils?

Answer 23

50 to 70%

Question 24

What are neutrophils important for?

Answer 24

important for bacterial and fungal infections, last only hours to a few days in circulation

Question 25

what does adaptive immunity involve?

Answer 25

Involves humoral and cell mediated responses that involve the T and B lymphocytes

Question 26

Adaptive immune responses are...

Answer 26

... specific

Question 27

Adaptive immune responses are ‘specific'. What does this mean?

Answer 27

each lymphocytes activation receptor will recognise a specific antigen lymphocyte is different.

Question 28

What do humoral responses involve?

Answer 28

involve the production and secretion of immuno globulin proteins (antibodies) – B lymphocytes

Question 29

What do cell mediated responses invovle?

Answer 29

involve cytotoxicity – T lymphocytes (lots of different types)

Question 30

What percentage of leukpcytes are lymphocytes?

Answer 30

30% of leukocytes

Question 31

What can lymphocytes form?

Answer 31

can form memory cells which can last for years (basis of vaccination)

Question 32

Define antigen

Answer 32

“substance that is capable of inducing an immune response”

Question 33

Antigens can be...

Answer 33

‘non-self’, ‘altered-self’ or ‘self’

Question 34

What antigens are 'non-self'?

Answer 34

Foreign invaders microorganisms - Endotoxins (bacteria) - Exotoxins (bacteria)

Question 35

what antigens are altered self?

Answer 35

- Viral infected cells - Malignant cells

Question 36

What antigens are autoimmune ?

Answer 36

to attack self.

Question 37

Define epitope

Answer 37

Immunogenic region of an antigen – important for adaptive immunity

Question 38

WHats haematopoiesis?

Answer 38

blood cell development

Question 39

All blood cells (leukocytes and erythrocytes)

Question 40

23

Question 41

Haematopoietic stem cells (HSC) are...

Answer 41

‘multi-potent’

Question 42

Haematopoietic stem cells (HSC) are ‘multi-potent’ and able to differentiate into: ?

Answer 42

- Leukocytes - Erythrocytes - Platelets

Question 43

The process of haematopoiesis is under...

Answer 43

under strict regulation & ensures that blood cell development occurs in accordance with specific needs

Question 44

The initial step in haematopoiesis is ...

Answer 44

... to whether follow a ‘myeloid’ or an ‘lymphoid’ differentiation path – committed

Question 45

Specific cytokines & chemokines dictate...

Answer 45

... the direction that haematopoietic stem cells differentiate

Question 46

What drives HSC differentiation to a common lymphoid progenitor?

Answer 46

FLT-3 ligand, tumour necrosis factor (TNF-α), transforming growth factor (TGF-β) in combination with (interleukin ) IL-2, IL-7, IL-12 and stromal cell derived factor (SDF-1)

Question 47

what drives HSC differentiation to a common lyeloid progenitor?

Answer 47

- GM-CSF = granulocyte macrophage colony stimulating factor - G-CSF = granulocyte colony stimulating factor - EPO = erythropoietin - TPO = thrombopoietin - SCF = stem cell factor

Question 48

How are blood cells distinguished?

Answer 48

Blood cells are distinguished by light microscopy following haematoxylin and eosin (H&E) staining.

Question 49

What colour do eosinophils stain?

Answer 49

stain red since cytoplasmic vesicles contain basic proteins that bind ‘eosin’ an acid dye

Question 50

What colour do basophils stain?

Answer 50

stain blue as they bind the basic dye ‘haematoxylin’

Question 51

What defines a set of diseases known as leukaemia?

Answer 51

Blockade in haematopoiesis

Question 52

leukaemia can occur at various stages during...

Answer 52

... myeloid or lymphoid development (myeloid leukaemia / lymphoid leukaemia).

Question 53

Genetic mutations prevent...

Answer 53

... normal differentiation, leading to over proliferation of ‘non-functional’ blast cells (cancer)

Question 54

What happens in the bone marrow due to genetic mutations?

Answer 54

Bone marrow over-crowded, reduced normal functioning blood cells (symptoms), bone marrow failure and death

Question 55

What are the primary sites (organs) of the immune system?

Answer 55

Thymus (T cells) Bone marrow (granulocytes B cells)

Question 56

what are primary lymphoid organs?

Answer 56

Sites in the body where granulocytes / lymphocytes are synthesised (and matured) in an antigen independent setting

Question 57

What occurs at the primary lymphoid organs?

Answer 57

- lymphocyte generation and education - central selection - diversification

Question 58

What are secondary lymphoid organs?

Answer 58

Sites where immuno-competent T and B lymphocytes are exposed to antigen (activated) through antigen presentation processes

Question 59

What are the secondarey lymphoid organs?

Answer 59

1) Lymph nodes (antigen from extracellular tissue fluid) 2) Spleen (antigen from blood) 3) Mucosal Associated - Lymphoid Tissue (MALT) Peyer’s patches (gut), appendix, tonsils and adenoids