Lecture 3

Question 1

Where does the Ag bind to the BCR?

Answer 1

the V region of both the H chain and the L chain

Question 2

How many Ag binding sites do BCRs/TCRs have?

Answer 2

BCR 2, TCR 1

Question 3

What are the gene segments that are joined together to encode for the v region of the BCR H, TCR beta and delta chain?

Answer 3

V, D and J

Question 4

What are the gene segments that are joined together to encode for the v region of the BCR L chain, TCR alpha and gamma chain?

Answer 4

V and J

Question 5

What factors contribute to diversity of BCRs/TCRs?

Answer 5

• any V/D/J or V/J segment can be combined
• in B Cells: any H chain pairs with any L chain
• in T Cells: any alpha with any beta, or any gamma with any delta

Question 6

Are there multiple chances for recombination in a B cell H chain?

Answer 6

no– there would be no additional D segments to allow for recombination
- in B cell, one chance per chromosome

Question 7

Are there multiple chances for recombination in a BCR L or TCR A or G chain?

Answer 7

yes, until all V and J segments are used up
- unless the first V segment and the last J segment are used up

Question 8

What are the two types of BCR L chain?

Answer 8

kappa and lambda

Question 9

Are there multiple chances for recombination in a T cell beta chain?

Answer 9

yes two chances, because two D regions and 2 J regions

Question 10

What is the leader sequence?

Answer 10

before each V region, targets mRNA to the ER

Question 11

Are there multiple chances for recombination in a T cell delta chain?

Answer 11

no: there would be no additional D segments to allow for recombination