Adaptive immunity

Question 1

immune memory consists of

Answer 1

T and B lymphocytes

Question 2

T cells and antibodies can

Answer 2

recognise infinite number of targets

Question 3

when does the adaptive system kick in

Answer 3

2-4 days after

Question 4

adaptive immune system is specfic

Answer 4

to the given organism

Question 5

why is the adaptive immune system useful

Answer 5

it is rapidly protective on re-exposure from the same infectious agent

Question 6

property of the adaptive immune system

Answer 6

forms basis for the protective effects of vaccination

Question 7

antigen

Answer 7

any molecules or part of a molecule recognised by the variable antigen receptors of lymphocytes are known as antigens

Question 8

what does a vaccine do

Answer 8

• Priming the body for a pathogen
• Ability of body to remember an infectious agent to which it has been exposed – basis for natural and artificial immunity
• initiates production of memory cells
• they will recognise agent an produce massive number of lymphocytes and immunoglobulins that overwhelm invaders

Question 9

founding father of immunology

Answer 9

Edward Jenner

Question 10

E Jenner

Answer 10

• Observed that naturally occurring pustualar eruptions on the teats of cows could be transferred to the hands or arms of milkers but they had natural immunity against smallpox
  o Demonstrated that injecting fluid from cowpox pustules into skin of children led to acquisition of a high degree of immunity to smallpox

Question 11

the lymphatic system provides

Answer 11

a critical interact bw activated dendritic cells and lymphocytes

Question 12

Lymphocytes enter the…

Answer 12

lymphoid tissue to be activated by dendritic cells

-return to the bloodstream though the lymph if not activated

Question 13

what controls migrations through lymphoid tissue and cellular interactions

Answer 13

guided and controlled by adhesive cell surface molecules whose expression is regulated by cytokines and chemokine

Question 14

name 4 innate granulocytes

Answer 14

neutrophils
eosinophil
basophil
monocyte
dendritic cell

Question 15

name 2 cells of the adaptive immune system

Answer 15

B lymphocyte (matures in bone marrow)

T lymphocyte (matures in thymus)

Question 16

name some lymph tissue

Answer 16

• adenoid
• tonsil
• lymph node
• thymus
• heart
• thoracic duct
• spleen
• Peyers patch in small intestine
• appendix
• large intestine
• bone marrow
• lymphatics- e,g. in legs

Question 17

how do T lymphocytes recognise antigens?

Answer 17

via T cell receptors generated during their differentiation- they interacts wit AMPCs via complementary ligand

Question 18

each T lymphocyte expresses an antigen receptor of only

Answer 18

one specificity- whole population of lymphocytes is collectively capable of recognising any antigen

Question 19

describe the structure of the T cell receptor

Answer 19

• transmembrane
• invariant constant (c) region- closest to the membrane and the same in all T cells
• V variable regions made up of an alpha and beta chain and different in all T cells

Question 20

what are Clusters of Differentiation

Answer 20

• major classes of T cells often referred to as CD4 and CD7

Question 21

CD4

Answer 21

a marker of helper T cells- MHCII

Question 22

CD8

Answer 22

a marker of cytotoxic T cells- MHC I

Question 23

MHC are

Answer 23

co-receptors that plan an important role in signal transduction on antigen bind by T cells

Question 24

dendritic cells

Answer 24

play a crucial role in activating the adaptive immune system

Question 25

dendritic cells begin life

Answer 25

as a phagocyte but activated by conserved components of micro-organism of by inflammatory cytokines released by macrophages

Question 26

once activated dendritic cells become dedicated to

Answer 26

displaying components of ingested micro-organism for recognition by naive T cells and subsequent differentiation of naive T lymphocytes into effector T cells

Question 27

T lymphocytes role | CD8T+/cytotoxic T cells

Answer 27

kill viruses, infected and cancerous cells

Question 28

T lymphocyte role | CD4+

Answer 28

activate other cells of the immune system

Question 29

B lymphocytes

Answer 29

secrete immunoglobulins

Question 30

lymphoid lineage

Answer 30

cellular differentiation

Question 31

mature lymphocytes which have no yet encountered antigen are known as

Answer 31

naive lymphocytes

Question 32

how Naive cells differentiate

Answer 32

differentiation into effector cells is stimulated by encounter with antigen and preceded with a vigorous proliferation that selectively expands the numbers of those lymphocytes with receptors specific for the inducing antigen. clonal expansion of antigen-specific lymphocytes

Question 33

where do T helper cells and cytotoxic T cells fully mature

Answer 33

peripheral tissue- äter stimulation in lymphoid tissue by dendritic cells

Question 34

Natural Killer cells

Answer 34

Lymphoid lienage contains third major cell type which lacks antigen-specific receptors and is capable of killing virus-infected cells immediately without prior activation or clonal expansion. Regarded as part of INNATE immune system- don’t need prior activation.

Question 35

activation of NK cells

Answer 35

occurs via binding of activated receptors to surface molecules produced by cell damage e.g. cancer or those encoding infectious viruses

Question 36

what stimulate the lymphoid pathway

Answer 36

cytokines

Question 37

describe the lymphoid pathway

Answer 37

- Move into either blood stream or thymus (thymocytes- a nursery for T cells)- then move into the blood cell as mature but naïve helper T cells, then migrate to secondary lymphoid tissues and wait to receive info from dendritic tissues) - Dendritic cells go straight from bone marrow into the blood and then to the secondary lymphoid tissue where is interacts with T cell

Question 38

where are dendritic cells numerous

Answer 38

epithelial and mucosal surfaces

Question 39

langerhans

Answer 39

o first recognised in the skin in the 19th century. They are as a subset of dendritic cells that reside in the keratinised epidermis for several months

Question 40

Second population of skin-resident dendritic cells is found in the dermal layer - known as

Answer 40

dermal dendritic cells

Question 41

in mucosal epithelium of the gut

Answer 41

dendritic cells are concentrated are specialised sites of antigen collection which overlie lymphoid tissues

Question 42

some cells of the mucosal epithelium of the gut

Answer 42

have specialised surface properties that enable them to extend their long dendritic processes between the cells of the epithelium and into the lime to sample antigens --> these cells are directly exposed to ingested antigens and to commensal bacteria

Question 43

processes of the dendritic cell (in the mucusal epithelium)

Answer 43

have a specialized role in preventing inflammatory responses to harmless gut residents

Question 44

summary of activation of the adaptive immune system

Answer 44

1) dendritic cell displays a component of microorganism for recognition by T cell bearing a receptor for that component 2) stimulates it to proliferate and differentiate into effector cell 3) when effector cell recognised the same antigen displayed on the surface of B cell, the T cell activates the B cell 4) B cell proliferates and secretes antibodies that recognised the micro-organism

Question 45

T cell targeting

Answer 45

Unlike B cells whose surface immunoglobulin molecules are adapted to serve as antigen receptors, T cells are unable to interact directly with intact antigen so must interact with other cells of the immune system.

Question 46

who do T cells know which cells to interact with

Answer 46

T cells are focused on their target cell by MHC molecules - which carry fragment of antigen (usually peptide fragments of proteins) fro internal compartments of the target cell surface and display them for recognition by T cells

Question 47

all naive T cells are

Answer 47

activated by antigen fragments displayed on MHC molecules on the surface of Dendritic cells - after activation they are triggered to kill or activate cells displaying the same complex of MHC and antigen

Question 48

which cells have MHC molecules

Answer 48

dendritic cells

Question 49

who discovered that MHCs were related tot he rejection of skin grafts

Answer 49

Peter Medawar (1944)

Question 50

Peter Medawar

Answer 50

Became a clinical immunologist because of WWII - the large number of burns victims presented an opportunity to research skin graft rejection. Established that the timing and vigor of rejection is related to the degree of differences between histocompatibility antigens of donor and recipient. - Differences in the MAJOR HISTOCOMPATIBILITY COMPLEX result in rejection within the first week - Differences in the MINOR HISTOCOMPATIBILITY COMPLEX result in a slower rejection process. Medawar’s work led the way to the routine use of tranplantation. Matching of major histocompatibility antigens, at times with the use of immunosuppressants, means that kidney, lung and heart transplants are now commonplace.