L17: T cells and Immune Regulation

Question 1

Class I HLA molecules display small fragments of proteins synthesized ____. This is how an ____ can be detected by T
cells and how ____ antigens are detected too.

Answer 1

in the cell, intracellular protein, intracellular pathogen

Question 2

what is found on each T cell

Answer 2

CD3

Question 3

what happens when the antigen presented in the correct MHC on the correct APC and finds the correct T cell with correct TCR?

Answer 3

• Helper cells will provide t cell with cytokines
• Proliferation and differentiation because of cytokines it is receiving → drives proliferation of T cell
• proliferation for copies to go out in the periphery to find viral infection etc.
• “Army of T cells” t go fight infection → effector cells, control and regulate infectious environment
• Memory population of T cell clones with same TCR specificity → long term immunity/protection

Question 4

what are the two signals for T cells

Answer 4

signal 1 - soluble mediators (cytokines and hormones)
signal 2 - surface interactions (co-stimulators)

Question 5

signal 1

Answer 5

antigen presentation

Question 6

signal 2

Answer 6

costimulatory signal to fully acitvate T cell

Question 7

what are the costimulatory molecules on the TCR and APC respectively

Answer 7

• B7 (CD80 and CD86) on APC
• CD28 receptor on T cells

Question 8

what happens when there is no costumulation

Answer 8

anergy - no signal 2 - no fully activation of T cell

Question 9

what is signal 3

Answer 9

APC release cytokines to further activate T cell

Question 10

what is the general role of cytokines

Answer 10

regulation

Question 11

cytokines are often called

Answer 11

interleukins

Question 12

give some examples of cytokine jobs

Answer 12

chemotactic, pro-inflammatory, ant-inflammatory

Question 13

cytokines innate or adaptive

Answer 13

released from innate cells

Question 14

what are haematopoetic cytokines

Answer 14

replenish lost cells