Adaptive Immunity

Question 1

what ability do adaptive immune cell receptors have that innate receptors do not?

Answer 1

Ability to reaarrange their structure

Question 2

what type of cells usually express MHC 1

Answer 2

virally infected cells

Question 3

what type of cells usually express MHC 2

Answer 3

antigen presenting cells

Question 4

What does the co receptor CD8 bind to

Answer 4

MHC 1 proteins

Question 5

what does the co receptor CD4 bind to

Answer 5

MHC 2 proteins

Question 6

what co receptor do both CD8+ and CD4+ TCRs both have

Answer 6

CD3

Question 7

what are the 2 possible chain combinations in T cell receptors

Answer 7

alpha and beta (majority)

delta and gamma

Question 8

what are the three regions of T cell receptors

Answer 8

transmembrane region
constant region
variable region

Question 9

what gene segments encode the variable region of the alpha chain

Answer 9

V and J

Question 10

what gene segments encode the variable region of the beta chain

Answer 10

V, D and J

Question 11

what does VDJ recombination allow for

Answer 11

different receptor structures that can recognise different antigens
due to the many combinations t cells can recognise millions of antigens

Question 12

what is the aim of thymic education

Answer 12

to stop any potential autoimmune conditions

Question 13

describe the process of positive selection in thymic education

Answer 13

TCR on t cells interact with MHC proteins on thymic cells. If there is no recognition of these proteins the cell is destroyed by apoptosis

Question 14

describe the process of negative selction in thyic education

Answer 14

Tests how T cells interact with self antigens. If there is a strong interaction these cells are destroyed by apoptosis

Question 15

what are the three signals required to activate CD4+ t cells

Answer 15

signal 1 - interaction between TCR and MHC II/ on APC
signal 2 - co stimulatory molecules interact
signal 3 - cytokines produced by APC dictate what type of subset of CD4+ it becomes

Question 16

what are the three signals required to activate a CD8+ t cell

Answer 16

signal 1 - interaction between TCR and MHC I
signal 2 - co stimulatory molecules interact
signal 3 - Cytokines produced by APC tells cell to have effector function e.g produce destructive enzymes

Question 17

What are B cell receptors made of

Answer 17

antibodies

Question 18

IgM

Answer 18

antibody that is both a B cell receptor and also produced by B cells before they class switch

Question 19

IgG

Answer 19

most abundant antibody, gives resistance to viruses, bacteria etc
a further 4 subsets

Question 20

IgA

Answer 20

found in glandular secretions e.g saliva

aim to attack pathogens before they reach internal tissues

Question 21

IgE

Answer 21

involved in allergic reactions

Question 22

IgD

Answer 22

B cell receptor

Question 23

what are the three main functions of antibodies in the human body

Answer 23

neutralisation - neutralise the threat
opsonisation - coating of pathogen with antibodies making it more readily taken up by macrophages
complement initiation - via the classical pathway

Question 24

what are the two chain types in B cell receptors

Answer 24

heavy and light

Question 25

what gene segments are rearranged to make the b cell receptor heavy chain

Answer 25

V D and J

Question 26

what gene segments are rearranged to make the b cell receptor light chain

Answer 26

V and J

Question 27

what antibody makes up immature B cell receptors

Answer 27

IgM

Question 28

what antibodies make up mature B cell receptors

Answer 28

IgM and IgD

Question 29

describe the process of negative selection for B cells

Answer 29

Bone marrow cells will express self peptides, if the immature B cells react with them they will be engulfed by macrophages. tests for reactivity against self antigens

Question 30

thymus dependent activation

Answer 30

activation of B cell with help of T cells

Question 31

thymus independent activation

Answer 31

activation of B cells without help of T cells

Question 32

describe the process of antigen dependent activation of B cells

Answer 32

``` T cell and B cel linteractions require co receptor binding Cytokine signals from Th cells help induce proliferation which produces plasma and memory cells plasma cells initially produce IgM before class switching to IgG (most common) ```

Question 33

describe the process of antigen independent activation of B cells

Answer 33

certain antigens can activate B cells directly cells differentiate into plasma cells and produce IgM (later switch to IgG) No memory B cells are produced and response is much weaker than antigen dependent activation

Question 34

affinity

Answer 34

strength of single body binding to antigen

Question 35

avidity

Answer 35

ability of antibody to form complexes

Question 36

central tolerance

Answer 36

2 types of selection for T cells - occurs in the thymus 1 type of selection for B cells - occurs in the bone marrow If mechanisms dysfunctional can lead to allergies/ autoimmunities

Question 37

peripheral tolerance

Answer 37

takes place in immune periphery against T and B cells that have escaped central tolerance