Ch 5

Question 1

How are the BCR and the TCR analogous structures?

Answer 1

• I BCR FAB region is the same as TCR
• produced by gene rearrangment
• heavy chain= Beta chain TCR
• Light chain= alpha chain TCR

Question 2

how are the BCR and TCR different?

Answer 2

• no secreted form of T cell
• t cells only recognize only peptide antigen plus MHC.

Question 3

what is the CD3 complex of T-cells

Answer 3

One epsilon delta dimer, one epsilon gamma dimmer and one zeta heterodimer under the cell membrane

Question 4

what is the function of the CD3 complex?

Answer 4

CD3 complex binds and carries the TCR to the surface membrane. it provides intracellular signaling

Question 5

what are the 2 classes of TCR

Answer 5

Alpha/beta
delta/gamma
alpha beta most common

Question 6

how do gamma and delta chains compensate for less v-segments

Answer 6

2 d segments can be joined for delta. This helps with gene diversity and creates more n-nucleotides

Question 7

what are some characteristics of gamma/delta t-cells

Answer 7

• they don’t need MHC for antigen recognition
• recognize a wider variety of antigens
• found mostly in the gut

Question 8

where is the Delta VDJ gene segment located?

Answer 8

Between the alpha VJ segment of chrom. 14

Question 9

what happens when you join a VJ

Answer 9

the delta gene segment is clipped out

Question 10

what chromosome are gamma gene segments found?

Answer 10

chromosome 7

Question 11

what is antigen processing? of the T-cell

Answer 11

intracellular degredation of pathogens

Question 12

how is an antigen presented?

Answer 12

the peptide 9-24aa binds to MHC and is expressed on the cell surface.

Question 13

what is the cell order for antigen processing?

Answer 13

1- dendritic cells
2- b-cells
3- macrophages

Question 14

what co-receptor bind MHC 1

Answer 14

CD8 cytotoxic t-cells

Question 15

what co-receptor binds MHC 2

Answer 15

CD4 helper t-cell (cytokines)

Question 16

What Ig domain of the MHC1 does CD8 bind to?

Answer 16

alpha 3 domain

Question 17

what IG domain of MHC2 does CD2 bind to?

Answer 17

beta 2

Question 18

how do the MHC1 peptides bind

Answer 18

• the n and c terminus of the 9aa peptides are the only things that bind. there are 2aa side chains called the anchor residues that binds the pocket. the other side chain points outwards for t-cell interaction.

Question 19

how do the MHC 2 peptides bind

Answer 19

not restricted to a 9aa peptide like MHC1
- 10-25aa peptide chain hangs over the edges of the groove.
- 8-10 aa long peptide binds the groove; core epitope. there are nested sets
- 3-4 anchor residues bind the pocket.