WEEK 2 - overview of white blood cells

Question 1

how to study WBC

Answer 1

blood / bone marrow smears

two push-type peripheral blood smears suitable or characterisation of cellular blood elements

Question 2

what does leucocyte mean?

Answer 2

white cell

phrase leucocyte and lymphocyte are not interchangeable

Question 3

blood smear

Answer 3

humans contain about 5 litres of blood
accounts for 7% of body weight
red cells constitute 45% of blood volume
white blood cells around 1%

Question 4

are leucocytes more prominent in blood or bone marrow

Answer 4

very prominent in bone marrow

(more rare in the blood)

Question 5

bone marrow
trephine biopsy

Answer 5

Fine needle (apple core) of bone marrow (long thin bit of tissue)
- Keeps its structure

Question 6

what do you see in a bone marrow sample

Answer 6

shows normal architecture and cellularity
- haemopoietic cells
- fat spaces

Large amounts of fat deposit in bone marrow
- Fat soluble vitamins
- To support the production of cells

Question 7

normal bone marrow smear

Answer 7

cannot see structure (the fat)

shows haemopoietic cells at different stages of maturation

Question 8

myeloid progenitor cells from bone marrow

Answer 8

bone marrow –> hematopoietic stem cells –> myeloid progenitor cells

from myeloid cells
- erythrocytes
- monocyte
- neutrophil
- basophil
- eosinophil
- platlets

Question 9

lymphoid progenitor cells from bone marrow

Answer 9

bone marrow –> hematopoietic –> lymphoid progenitor cell

fom lymphoid cell
- t-cell
- b-cell

Question 10

how does the system (of WBCs) maintain themselves
- how does the cell make large numbers of differentiated cells

Answer 10

stem cells and committed cells are rare so need to proliferate
- bulk numbers

cell renewal
- stem cells are also able to generate new stem cells

committed transit amplifying cell (proliferation)

precursor cells
- terminally differentiated cells

Question 11

stem cell definition

Answer 11

a population of cells able

1. to sustain themselves by a process of self-renewal
2. to generate progeny that sustain both the mass and functional competence of the tissue

Question 12

differentiation system
regulation?

Answer 12

incredibly complex regulation

as cells pass through system become increasingly restrictive (less able to make other cells)

Question 13

human b cell differentiation

Answer 13

[bone marrow]
large pre b cell –> small pre b cell –> immature b cell

[spleen or lymph node]
–> mature b cell

[marginal zone]
–> marginal zone b cell

[germinal centre (secondary follicle)]
–> germinal centre B cell
———> memory B cell
———-> plasma cell

Question 14

spleen colony assay

Answer 14

how we knew self renewal was the case

1961-1964
establishment of assay for cells able to repopulate irradiated host

spleen from mice (big white patches on spleen are clones of cells

Question 15

spleen colony assay
method

Answer 15

radiated mice at various radiations

syngeneic bone marrow cells transplanted

remove the spleen and examine

the mice no longer die if injected

No. of colonies on spleen related to how much bone marrow was put in
- More bone marrow, more colonies

Whatever this cell is that does this is capable of making multiple different cells
Again and again
This is a stem cell (first idea that a cell can 1) self renew 2) proliferate like mad 3) differentiate

Question 16

spleen colony assay
spleen colonies contain renewing cells

Answer 16

This led directly to the current routine stem cell transplant therapy

Question 17

spleen colony assay
bone marrrow restores…

Answer 17

hematopoiesis in irradiated mice

Hematopoiesis is the process of producing new blood cells and plasma

Question 18

spleen colony assay
all cell lineages…

Answer 18

recover

Question 19

spleen colony assay
chromosome marking shows…

Answer 19

that spleeen cell colonies derive from a single cell that became know as the colony forming unit-spleen (CFU-s)

Question 20

spleen colony assay
CFU-s are…

Answer 20

rare
~1 per 10^4% bone marrow leucocytes

Question 21

spleen colony assay
cells from a single colony can…

Answer 21

restore all lineages in a secondary recipient showing that CFU-s are capable of self renewal

Question 21

spleen colony assay
mixed colonies demonstrate…

Answer 21

that CFU-s are multipotent

Multipotency defines the cell’s ability of self-renewal and developing into multiple specialized cell types present in a particular tissue or organ

Question 22

how does the system maintain itself
granulocyte/erythrocyte/megakaryocyte/monocyte - colony forming units

Answer 22

Culture in vitro
Jelly like tissue culture medium
When cells grows within it, it restricts the cells from spreading so make colonies in place

myelo-erythroid progenitor

Question 23

how does the system maintain itself
burst forming unit - erythroid

Answer 23

bust forming unit - erythroid

More restricted but Can make multiple cell types

Question 24

how does the system maintain itself? colony forming unit - erthroid

Answer 24

final precursor that can only give one cell type

Question 25

morphology relates to...

Answer 25

function

Question 26

red blood cells

Answer 26

transport O2 and CO2 typical conc. 5 x 10^12 cells/litre half life measured in days

Question 27

red blood cells development

Answer 27

bone marrow: early normoblast --> late normoblast --> nucleated red cell --> reticulocyte --> blood: --> red cells

Question 28

neutrophils

Answer 28

phagocytose and destory invading bacteria typical concentration around 5 x 10^9 cells/litre half life measured in hours-days

Question 29

neutrophil development

Answer 29

bone marrow: myeloblast --> promyelocyte --> myelocyte --> metamyelocyte --> blood: --> unsegmented neutrophil (band form) --> neutrophil

Question 30

neutrophil nets

Answer 30

neutrophil extra cellular traps or NETs extra cellular meshes composed of chromatin and neutrophil proteins NETs are released upon cellular activation they entrap bacteria while simulataneously providing a scaffold to promote high local concentrations of anti-microbial components thus killing microbes extracellularly

Question 31

eosinophils

Answer 31

destroy larger parasites modulate allergic inflammation typical concentration around 2 x 10^8 cells/Litre

Question 32

basophils

Answer 32

release histamine in certain immune reactions typical concentration around 4 x 10^7 cells/Litre

Question 33

monocytes

Answer 33

become tissue macrophages phagocytose microorganisms and damaged or senescent cells typical concentration around 4 x 10^8 cells/Litre

Question 34

which WBCs are part of non specific immunity

Answer 34

neurotphil monocyte eosinophil basophil

Question 35

which WBCs are part of specific immunity

Answer 35

lymphocyte

Question 36

Lymphocytes T-lymphocytes

Answer 36

t cells kill virus-infected cells regulate activities of other leukocytes

Question 37

lymphocytes B-lymphocytes

Answer 37

B cells make antibodies (immunoglobulins) --> plasma cells in bone marrow

Question 38

lymphocytes Natural killer cells

Answer 38

NK cells kill virus infected cells and some tumour cells innate cells they serve to contain viral infections while the adaptive immune response is generated

Question 39

immunofluorescence what

Answer 39

a light microscopy-based technique that allows the detection and localization of a wide variety of target biomolecules within a cell or tissue at a quantitative level. utilizes the binding specificity of antibodies and antigens.

Question 40

immunofluorescence method

Answer 40

incubate with fluorescent tagged antibody wash analyse by microscopy or flow cytometry

Question 41

flow cytometry what

Answer 41

a lab test that uses lasers to analyze the physical and chemical properties of cells and particles in a fluid fluorescence activated cell sorting (FACS)

Question 42

flow cytometry how does it work

Answer 42

Cells are labeled with fluorescent dyes, which emit light when exposed to a specific laser. The light signals are converted to electronic signals and analyzed by a computer

Question 43

overview leucocytes are generated from...

Answer 43

a common stem cell resident in the bone marrow

Question 44

overview production of vast numbers of cells are generated...

Answer 44

each day throughout life

Question 45

overview production of vast no. of cells brought about by...

Answer 45

integrated processes of cell proliferation, differentiation, maturation and apoptosis

Question 46

overview leucocytes perform..

Answer 46

various roles in host defence

Question 47

overview what has made the blood system particularly easy to follow

Answer 47

the advent of flow cytometry, monoclonal antibodies and FACs