L19: Immunology II

Question 1

How can B & T cells make enough different antibodies to recognise all pathogens?

Answer 1

Generation of antibody diversity - VDJ recombination

Question 2

What does immunoglobulin (secreted antibody & BCR) recognise?

Answer 2

Whole antigen

Question 3

What is VJ segment?

Answer 3

Kappa/lambda light chain

Question 4

What is VDJ gene segment?

Answer 4

Heavy chain

Question 5

How do B cells generate diverse immunoglobulins?

Answer 5

Cutting & pasting gene segments together

Question 6

What does the junction between V,D & J segments determine?

Answer 6

Antigen specificity

Question 7

What are framwork regions encoded by?

Answer 7

V segments

Fold to form the domain structure of the variable region

Question 8

What do CDRs determine?

Answer 8

Antigen binding specificity

Question 9

What is CDR 3 encoded by?

Answer 9

VDJ junction

Question 10

How many classes of TCR can T cells express?

Answer 10

2
‘Normal’ T cells express alpha-beta TCR genes

‘Unconventional’ T cells express gamma-lambda TCR genes

Question 11

How can TCR be made?

Answer 11

Rearrangment of VDJ segments

Question 12

What recombination makes a-chain & b-chain

Answer 12

a-chain: VJ
b-chain: VDJ

Question 13

Recombination in B cells
1st
2nd
3rd

Answer 13

1st: Heavy chain D-J
2nd: Heavy chain V-DJ
3rd: Light chain V-J

Question 14

Recombination in T cells
1st
2nd
3rd
3th

Answer 14

1st: gamma recombination V-J
2nd: … recombination D-J, then V-DJ if fails
3rd: beta recombination D-J, then V-DJ
4th: alpha recombination V-J

Question 15

Describe the Allelic Exclusion process

Answer 15

Each Ig/TCR gene has 2 alleles, but only 1 must be rearranged

Rearrangement starts on 1 allele, if unsuccessful, 2nd allele rearranges, if this is unsucccessful, cell dies

Question 16

Define central tolerance

Answer 16

Eliminating T/B lymphocytes that are autoreactive