Lecture 2

Question 1

which gene segments encode the V region of the H chain and TCRbeta?

Answer 1

V
D
J

Question 2

which gene segments encode the v region of the L chain and TCR alpha?

Answer 2

V

J

Question 3

when does gene rearrangement occur?

Answer 3

during B cell development

Question 4

what is the name of gene rearrangement?

Answer 4

non-homologous end joining recombination (NHEJ)

Question 5

how does NHEJ occur?

Answer 5

after DNA breaks, a single V and a single J gene segment are joined together to encode the V region of the light chain

Question 6

does the heavy or light chain have greater variability?

Answer 6

H chains as they have V, D and J gene segments

Question 7

what are the sequences called which guide DNA rearrangement?

Answer 7

recombination signal sequences (RSS)

Question 8

what is light chain isotope exclusion?

Answer 8

a single B cell can only express either kappa or lambda, never both

Question 9

what are the 5 mechanisms for generating antibody diversity?

Answer 9

multiple germline genes 
combinatorial diversity
junctional diversity
combinations of heavy and light chains 
somatic hypermutation

Question 10

what us somatic hypermutation?

Answer 10

higher than normal spontaneous mutation rate
occurs in germinal centres as B cells recognise antigens and proliferate
uses the enzyme AID - activation-induced deaminase