Cells of the immune system?

Question 1

what drives cellular differentiation?

Answer 1

cytokines
- differentiation is also driven by the location of the stem cells

Question 2

what are the features of immature T and B cells?

Answer 2

found in the bone marrow
- the TCR/BCR genes are still in the germline state

Question 3

what is gene rearrangement of TCR/BCR genes?

Answer 3

DNA based mechanism that loops out genes, creating a new and unique DNA sequence

Question 4

what part of antibody genes are rearranged?

Answer 4

the heavy and light chains

Question 5

what part of T cell receptors undergo rearrangement?

Answer 5

Alpha and beta chains

Question 6

what is clonal expansion?

Answer 6

selective expansion of lymphocytes that interact with antigen

Question 7

what happens when B cells undergo clonal expansion?

Answer 7

the daughter cells produce antibody specific for the interacting antigen

Question 8

what can help determine an adaptive immune system?

Answer 8

immunization

Question 9

how do neutrophils respond during an infection?

Answer 9

they expand in response to infection

Question 10

what are the features of neutrophils?

Answer 10

-produced in the bone marrow
- most abundnat leukocyte but short-lived
-dead and dying neutrophils are a mjor component of pus
-Produced reactive oxygen species (ROS) and NETS

Question 11

what is the function of neutrophils producing reactive oxygen species?

Answer 11

they are used to kill microbes

Question 12

what are NETS?

Answer 12

DNA and histones that are released by a dying neutrophil

Question 13

why do neutrophils breakdown?

Answer 13

production of reactive oxygen species effects the ingegrity of the cell wall and othe essential parts of the cellular structure and so the neurophil dies

Question 14

what is the function of NETS?

Answer 14

Neutrophil Extracellular Traps bind bacteria

Question 15

what is the primary function of dendritic cells?

Answer 15

to excite the immune system

Question 16

what are the features of dendritic cells?

Answer 16

-Antigen-presenting cells that can activate naive T cells
-Express both MHC-I and MHC-II and costimulatory molecules
- Migratory function (ferry antigen from the periphery to the lymph node)
-all solid organs and blood contain dendritic cells

Question 17

what cell is responsible for acute transplant rejection?

Answer 17

dendritic cells

Question 18

what are the dendritic cell subsets derived from?

Answer 18

common myeloid progenitor cells

Question 19

what are the subsets of dendritic cells?

Answer 19

• Langerhans cells
• Dermal dendritic cells
• Thymic dendritic cells

Question 20

what are langerhans cells?

Answer 20

dendritic cells of the epidermis

Question 21

what are dermal dendritic cells?

Answer 21

cells specialised in cross-priming

Question 22

what is the role of thymic dendritic cells?

Answer 22

medial central tolerance

Question 23

what is central tolerance?

Answer 23

deletion of autoreactive T cells

Question 24

what allows cross priming?

Answer 24

the phagolysosome leaking into the cytoplasm

Question 25

what is exogenous processing?

Answer 25

outside 'stuff' gets loaded onto MHC-II

Question 26

what is endogenous processing?

Answer 26

inside 'stuff' gets loaded onto MHC-I

Question 27

what does MHC-II activate?

Answer 27

Helper T cells (CD4)

Question 28

what does MHC-I activate?

Answer 28

Cytotoxic T cells (CD8)

Question 29

what is the role of conventional dendritic cells?

Answer 29

Main subset involved in stimulating naive and memory T cells

Question 30

what is the role of plasmacytoid dendritic cells?

Answer 30

release large amounts of interferon type 1

Question 31

what is the role of interferon type 1?

Answer 31

puts the body into a state of high alert

Question 32

what is the role of peripheral tolerance?

Answer 32

keeps autoreactive immunes cells at bay

Question 33

what happens to immune cells that show a lack of co-stimulation?

Answer 33

lack of co-stimulation leads to anergy (non-responsiveness) or cell death

Question 34

what is the result of a cell undergoing co-stimulation?

Answer 34

leads to lymphocyte activation

Question 35

what are the features of macrophages?

Answer 35

- monocyte in the blood is a macrophage precursor - role in antigen clearance - monocytes can activate coagulation through upregulation of clotting factors

Question 36

how is macrophage activation enhanced by the immune system?

Answer 36

presentaion of intracellular antigens by macrophages leads to interactions with CD4 T cells CD4 T Cells then release INFg which activates anti-bacteria activity in macrophages

Question 37

what is the role of a natural killer cell?

Answer 37

Recognise inhibitory receptors on normal cells (MHC-I) If MHC-I is missing or altered, Natural killer cells become activated and lyse the target cell

Question 38

why does lack of MHC-I activate a natural killer cell?

Answer 38

build up of a positive signal to lyse the cell, which is inhibited by the presence of MHC-I, is not inhibited due to MHC-I not being present

Question 39

what are Natural Killer cells?

Answer 39

NK cells are primarily an innate cell, but are essential for the development of tumour immunity NK cells infiltrate lymph nodes and contribute to T cell activation

Question 40

how to natural killer cells help with cancer?

Answer 40

Caner and viruses interfer with the expression of MHC-I on the cell surface which can cause the NK cell to become activated

Question 41

what receptors are important for triggering macrophages and NK cells?

Answer 41

Fc receptors - recognises the fc region of an antibody

Question 42

how do natural killer cells kill host cells via antibody-dependent cellular cytotoxicity?

Answer 42

- Antibodies bind antigens on the surface of target cells - NK cell CD16 Fc receptors recognise cell-bound antibodies - Cross-linking of CD16 triggers degranulation into a lytic synapse - Tumour cells die by apoptosis

Question 43

what is a hot tumour?

Answer 43

high mutational burden

Question 44

why is a tumor with more mutations easier to generate a T cell response to?

Answer 44

There is a greater variety of peptides specific to the tumor that the T cells can recognise