Epitopes

Question 1

What is the actual binding site of an antigen?

Answer 1

Epitopes

Question 2

Do lymphocytes recognize entire antigens?

Answer 2

No, they recognize small, discrete sites

Question 3

What is an epitope?

Answer 3

Small, discrete site on macromolecules

Question 4

Antigenic determinants

Answer 4

Epitopes

Question 5

How do B-cell epitopes bind AG

Answer 5

B-cells bind Ag directly via cell surface immunoglobulin

Question 6

What can Ag be for B-cells?

Answer 6

Almost anything

Question 7

For Ag in solution for B-cells what three things must the epitopes be?

Answer 7

1. Topographically accessible (outside surface)
2. Flexible and mobile
3. Sequential or conformational (nonsequential)

Question 8

What is a conformational epitope?

Answer 8

Nonsequential

Distinct entities that fold together

Question 9

How is the epitope size defined?

Answer 9

Defined by the binding site of the antibody

Lock and key fit

Question 10

What limits epitope size?

Answer 10

Complimentary binding between Ag-Ab

Question 11

What can hold more aa? Conformational or linear

Answer 11

Conformational epitopes cover much greater space on flatter surface binding sites of Ab
Can hold 15-22 aa

Question 12

Do all epitopes induce a response?

Answer 12

No, there is immunodominance

Question 13

How many aa can typically fit in a linear epitope binding site?

Answer 13

6-7 aa or sugars

Question 14

What are the four shapes of epitopes for B cells?

Answer 14

1. Pocket
2. Hot dog in bun
3. Semi-circle
4. Sphere

Question 15

If I stretch out a conformational epitope will it work?

Answer 15

No, it needs to be in a 3D shape

Question 16

Linear

Answer 16

sequential

Question 17

Conformational

Answer 17

Non-sequential

Question 18

Can we denature and digest a linear epitope?

Answer 18

Yes

Question 19

Can we denature and digest a conformational epitope?

Answer 19

No

Question 20

What do T-cell epitopes see?

Answer 20

Only peptides

Question 21

Can a T-cell recognize soluble native Ag

Answer 21

No

Question 22

Can a T-cell bump into something and recognize it?

Answer 22

No, it needs to be instructed

Question 23

How does a T-cell recognize Ag?

Answer 23

The Ag has to be processed and whole peptide fragments are presented in association with MHC molecules

Question 24

MHC

Answer 24

Major Histocompatibility Complex

Question 25

Oligomer

Answer 25

“few parts”

Question 26

T-cell epitopes are oligomeric peptides of how many aa?

Answer 26

7-20 aa

Question 27

MHC class 1 is how many aa?

Answer 27

9-11 aa

Question 28

What does MHC 1 do?

Answer 28

Shows peptides to killer T-cells

Question 29

How many aa is MHC class 2?

Answer 29

11-17 aa

Question 30

What does MHC 2 do?

Answer 30

Shows peptides to helper T-cells

Question 31

What is required to generate peptides?

Answer 31

Ag processing

Question 32

Ag is seen as part of a trimolecular complex. What are the 3 parts?

Answer 32

TCR (tcell receptor)
Ag
MHC

Question 33

Peptides must be amphipathic. What two regions do they need?

Answer 33

Hydrophilic - TCR

Hydrophobic - MHC

Question 34

Hydrophobic

Answer 34

MHC

Question 35

Hydrophilic

Answer 35

TCR

Question 36

What does the TCR recognize?

Answer 36

MHC and peptide

Question 37

Agretope

Answer 37

MHC binding site of the Ag

Question 38

How do agretope sites bind?

Answer 38

Via hydrophobic aa

Question 39

Epitope

Answer 39

TCR binding site

Question 40

How do epitope sites bind?

Answer 40

Hydrophilic aa

Question 41

How are immunodominant T-cell epitopes determined?

Answer 41

By what set of MHC molecules are expressed and what TCR are expressed