Antigen Processing, Presentation, Co-Stimulation

Question 1

Can a T cell recognize an entire microbe?

Answer 1

NO.

Question 2

What is the only thing that will activate a T cell?

Answer 2

Cell surface PEPTIDES presented by cells that express MHC

Question 3

What is the primary Antigen-presenting cell?

Answer 3

Dendritic cells

Question 4

Where are dendritic cells found?

Answer 4

Mostly in skin, mucosa, lymph nodes, spleen, thymus

Question 5

Which MHC molecule do dendritic cells express?

Answer 5

MHC II

Question 6

Dendritic cells are the link between the ___________ and __________.

Answer 6

Innate and adaptive immune systems

Question 7

T/F: Macrophages are phagocytic cells.

Answer 7

TRUE

Question 8

T/F: Dendritic cells are important for both clearing debris (phagocytosis) and antigen presentation.

Answer 8

FALSE.

Macrophages!

Question 9

What are the three antigen presenting cells?

Answer 9

1. Dendritic cells
2. Macrophages
3. B cells

Question 10

What makes a cell a professional antigen presenting cell (APC)?

Answer 10

A cell that naturally expresses MHC II

Question 11

What interacts with the microbe at the site of infection?

Answer 11

Antigen Presenting Cell

Question 12

Where do APC and naive T and B cells interact?

Answer 12

Lymph nodes

Question 13

Which MHC is found on all nucleated cells?

Answer 13

MHC I

Question 14

Which cells have MHC II?

Answer 14

APCs

Question 15

What types of proteins are bound to MHC I?

Answer 15

Cytoplasmic proteins

Question 16

What types of proteins are found on MHCII?

Answer 16

Extracellular proteins

Question 17

T/F: CD8+ T cells recognize MHC II?

Answer 17

FALSE.

CD4+ recognizes MHC II

(II + II = 4)

Question 18

Give a brief description of the structure of MHC I?

Answer 18

Has two alpha subunits that create a cleft between them. This cleft is where the peptides bind

Question 19

Give a brief description of the structure of MHC II?

Answer 19

Alpha 1 and Beta 1 subunits create the peptide binding cleft.

Question 20

What are the two antigen processing pathways?

Answer 20

1. Extracellular proteins engulfed by professional APCs are processed and displayed by MHC II molecules
2. Cytoplasm proteins processed and displayed by MHC I molecules

Question 21

Understand the pathways for antigen processing!!

Answer 21

Look at the slides

Question 22

T/F: Once a T cell recognizes MHC, it will immediately activate.

Answer 22

FALSE.

Multiple receptors on T cells need to be engaged to activate the cell

Question 23

Which receptor recognizes the antigen in a T cell?

Answer 23

TCR

Question 24

Which proteins begin the signaling after TCR recognizes antigen?

Answer 24

CD3 (associated with TCR)

Question 25

In a T cell, _____ recognizes antigens, while _____ recognizes the corresponding MHC

Answer 25

TCR; CD4/CD8

Question 26

The binding of all of _____________ receptors in the ________ ________ of a T cell will activate the cell.

Answer 26

co-stimulatory; immunological synapse

Question 27

What are the co-stimulators molecules and their receptors?

Answer 27

1. B7 with CD28

2. ICAM-1 with LFA-1

Question 28

In order to deactivate a T cell, ____ will bind to ______.

Answer 28

B7; CTLA-4

Question 29

What two ways does CTLA-4 terminate the function of T cells.

Answer 29

1. Competes with CD28 for B7

2. Actively blocks signals from TCR and CD28 to the nucleus