lecture 1 - antibodies, T cell receptors and MHC molecules

Question 1

what are the organisms that causes disease

Answer 1

pathogens

Question 2

examples of pathogens

Answer 2

bacteria
viruses
fungi
worms
protozoa

Question 3

specific/adaptive response exhibits

Answer 3

memory

Question 4

what features allow specific immune response to have memory

Answer 4

• clonally distributed receptors
• large repertoire (cells have lots of different receptors)

Question 5

what is the lag phase

Answer 5

time from infection until you get your response

Question 6

lag phase in secondary response

Answer 6

much shorter and the number of antibodies is much higher

Question 7

when a specific lymphocyte binds to a foreign antigen that lymphocyte activate and is

Answer 7

clonally expanded

Question 8

lymphocytes are

Answer 8

t cells and b cells

Question 9

BCR (b cell receptor) is expressed by B lymphocyte and binds to

Answer 9

free antigens

Question 10

when the B cell is activated the BCR is released from the cell now known as an

Answer 10

antibody

Question 11

TCR is not dimeric, what two chains does it have

Answer 11

an alpha and beta chain

Question 12

the TCR only binds to antigens are being displayed to it by

Answer 12

MHC molecules

Question 13

TCR is always on the T cell and never

Answer 13

secreted

Question 14

MHCs are expressed by

Answer 14

APC (antigen presenting cells)

Question 15

how do antibodies interact with the complement system

Answer 15

via the constant heavy chain regions

Question 16

complement system can cause destruction of what very quickly

Answer 16

pathogens

Question 17

how do antibodies activate effector cells

Answer 17

the Fc region of the antibody can be recognised by activator cells via the FcR (Fc receptor)

Question 18

antibody structure:
what chains to antibodies have

Answer 18

2 light and 2 heavy chain

Question 19

the variable domains of the two chains form the

Answer 19

antigen binding site

Question 20

which domain does the FcR bind to

Answer 20

the constant region

Question 21

what are the 5 antibody classes/isotypes

Answer 21

IgM, D, A, G and E

Question 22

what region determines the class

Answer 22

heavy chain constant regions

Question 23

light chains has 2 domains, how many can heavy chain have

Answer 23

4 or 5

Question 24

each domain is how many amino acids

Answer 24

around 100

Question 25

how are the domains held together

Answer 25

by disulphide bridge

Question 26

in variable regions we have pieces that are hypervariable in each variable region how many hypervariable regions are there

Answer 26

3 (HV1-3)

Question 27

HV regions are the bits that are interacting with the

Answer 27

antigen

Question 28

what part of the antigen will the antibody recognise

Answer 28

the epitope

Question 29

a linear/continuous epitope

Answer 29

the parts that are bound are next to each other in primary structure

Question 30

non linear epitope

Answer 30

parts arent close together in the primary structure but are when folded into 3D structure

Question 31

antibody and antigen form what type of interactions

Answer 31

non covalent

Question 32

what does TCR recognise on the MHC

Answer 32

peptide fragment of an antigen

Question 33

how many domains does a TCR have

Answer 33

4

Question 34

how many CDRs (complementary determining regions) are there in TCR

Answer 34

3

Question 35

what does MHC stand for

Answer 35

major histocompatibility complex

Question 36

MHC class I molecules are expressed in

Answer 36

nearly all cells types in the body

Question 37

class I is how many chains

Answer 37

1

Question 38

what are the subunits of the MHC class I

Answer 38

α1,2 and 3, β2 microglobulin

Question 39

MHC class II has how many chains

Answer 39

2, alpha and beta chain

Question 40

what are the domains in MHC class II

Answer 40

β1 and 2, α1 and 2

Question 41

MHCs are every polymorphic which means there are many

Answer 41

alleles of MHC molecules

Question 42

what are the 3 MHC class I molecules

Answer 42

HLA-A, HLA-B and HLA-C

Question 43

what are the 3 MHC class II molecules

Answer 43

HLA-DP, HLA-DQ and HLA-DR

Question 44

what cells are MHC class II molecules expressed in

Answer 44

APCs

Question 45

the groove on MHC class II is more ____ that the groove on MHC class I

Answer 45

open meaning it can bind a different array of proteins

Question 46

CD8 t cells binds to which MHC class

Answer 46

class I MHC by CD8 binding to the alpha1/alpha2 domain

Question 47

what does this binding do

Answer 47

stabilises TCR/MHC interaction

Question 48

CD4 t cells bind to which MHC class

Answer 48

class II by CD4 binding to the alpha2/beta2 domains