9 Leukocytes

Question 1

why does the proportion of leukocytes differ in cell types

Answer 1

Number depends on the health of the individual at the time

Question 2

what do cells become

Answer 2

lymphoid or myeloid

Mononuclear or PMN/granulocytes

Question 3

Lymphoid Mononuclear cells

Answer 3

• Nk cells
• CD8+T cells
• CD4+ T cells
• gamma delta cells
• B cells

Question 4

Myeloid Mononuclear cells

Answer 4

• dendritic cells

- monocytes: macrophages or dendritic cells

Question 5

Myeloid PMN/granulocytes cells

Answer 5

• neutrophils
• eosinophils
• basophils
• mast cells

Question 6

where do all cells come from

Answer 6

Cells all come from hematopoietic stem cells

Question 7

what can cells become

Answer 7

depending what their exposed to, whether they go down the lymphoid progenitor route or myeloid progenitor route

Question 8

Macrophage

Answer 8

phagocytosis and activation of bacterial mechanisms. Antigen presentation

Question 9

Dendritic cell

Answer 9

antigen uptake in peripheral sites (great due to long dendrites). Antigen presentation in lymph nodes

Question 10

Neutrophil

Answer 10

phagocytosis and activation of bactericidal mechanisms

Question 11

Eosinophil

Answer 11

(adaptive immune system needs to be on to recognise the pathogen) killing of anti-body coasted parasites – extracellular digestion

Question 12

Mast cell

Answer 12

release of granules containing histamine and other agents

Question 13

what do macrophage contain

Answer 13

Granules stuffed full of enzymes – activated when a pathogen is engulfed

Question 14

Complement of other molecules - macrophage

Answer 14

proteases, cytokines

Question 15

what neutrophils contain

Answer 15

Granules with enzymes to cut, also have specific granules

Question 16

complement of other molecules - neutrophils

Answer 16

leukotrienes, cytokines, prostaglandins

Question 17

macrophage killing

Answer 17

Bacteria binding to endocytic receptors of macrophages induce their engulfment a and degradation
Bacterial components binding to signalling receptors of macrophages

Question 18

neutrophil killing

Answer 18

Neutrophil expresses receptors for many bacterial constituents
Neutrophils engulf and digest bacteria to which they bind
Recognition through antibodies – needs to be later on in process as require antibodies from adaptive

Question 19

what do eosinophils contain

Answer 19

Contain granules stuffed with enzymes – released to damage a large pathogen

Question 20

complement of other molecules - eosinophils

Answer 20

cytokines, enzymes, prostaglandins, leukotrienes

Question 21

what does eosinophils do

Answer 21

Extracellular digestion

Question 22

what do mast cells contain

Answer 22

preformed mediators

Question 23

what is an example of a preformed mediator

Answer 23

histamine

Question 24

what happens when mast cells are activated

Answer 24

generates newly synthesised molecules

Question 25

complement of other molecules - mast cells

Answer 25

cytokines, prostaglandins, leukotrienes

Question 26

what do mast cells lead to

Answer 26

inflammation

Question 27

which cells are long lived

Answer 27

mast cells | eosinophils

Question 28

which cells are short lived

Answer 28

neutrophils - but they are constantly remade

Question 29

which cells are sessile

Answer 29

stationary - mast cells sit in tissues

Question 30

which cells are mobile

Answer 30

eosinophils | neutrophils

Question 31

when do natural killer cells not kill

Answer 31

- Interaction with uninfected healthy cell | - Interaction with healthy allogenic cell of very similar HLA-C type

Question 32

when do natural killing cells kill

Answer 32

- no interaction of MHC class 1 expression - Interaction with healthy autologous cell - Interaction of healthy allogenic cell of different HLA-C type

Question 33

Cytotoxicity - Cytotoxic T cells

Answer 33

Collision and nonspecific adhesion Specific recognition redistributes cytoskeleton and cytoplasmic components of T cell Release of lytic granules at cell contact site

Question 34

when does the cytotoxic T cell recognise

Answer 34

Cytotoxic T cell recognises complex of viral peptide with MHC class 1 and kills infected cells

Question 35

what are the cytotoxic effector molecules

Answer 35

- perforin - granzymes - granulysin - Fas ligand

Question 36

Regulation - helper T cell (CD4)

Answer 36

Naïve CD4 T cell forms proliferating T cell then to immature effector T cell

Question 37

what do immature effector T cell form

Answer 37

TH1 cell | TH2 cell

Question 38

what do the TH1 cells do

Answer 38

macrophage activation, B cell activation and production of opsonising antibodies e.g. IgG1

Question 39

what do the TH2 cells do

Answer 39

general activation of B cells to make antibodies

Question 40

how do T cells function

Answer 40

by making contact with other cells and inducing them

Question 41

which T helper cell is formed when

Answer 41

Depending on naïve T cell signal depends what T helper it will become

Question 42

what does TH17 make

Answer 42

interleukin 17

Question 43

what does Treg make

Answer 43

regulate immune response

Question 44

effect of IL-17

Answer 44

inflammatory response

Question 45

what activates a T cell

Answer 45

Co-stimulatory signal and specific signal

Question 46

when does T cell becomes anergic

Answer 46

Specific signal alone

Question 47

when is there no effect the T cell

Answer 47

Co-stimulatory signal alone

Question 48

how are naive T cells activated to give effector T cells - MHC class 1

Answer 48

``` naive CD8 T cell recognises peptide + MHC class 1 proliferation and differentiation of CD8 T cells ```

Question 49

how are naive T cells activated to give effector T cells - MHC class 2

Answer 49

``` naive CD4 T cell recognises peptide + MHC class 2 proliferation and differentiation of CD4 T cells ```

Question 50

effector functions of T cells - virus infected cell death

Answer 50

cytotoxic T cells travel to infected tissue where virus-infected cells present specific antigen virus-infected cell dies by apoptosis

Question 51

effector functions of T cells - bacteria killed

Answer 51

effector TH1 cells travel to infected tissue where macrophages infected with or containing bacteria present specific antigen activated macrophage kills bacteria

Question 52

effector functions of T cells - antitoxin antibodies

Answer 52

effector TH2 cells interact with antigen-specific B cells in lymphoid tissue plasma cells make antitoxin antibodies

Question 53

effects of antibody production on bacterial toxins

Answer 53

neutralisation - ingestion by macrophage

Question 54

effects of antibody production on bacteria in extracellular space

Answer 54

opsonization - ingestion by macrophages

Question 55

effects of antibody production of bacteria in plasma

Answer 55

complement activation - lysis and ingestion

Question 56

Antibody-dependent cell mediated cytotoxicty (ADCC)

Answer 56

Antibody binds antigen on surface of target cells Fc receptors on NK cells recognise bound antibody Cross linking of Fc receptors signals the NK cell to kill target cell Target cell dies by apoptosis