TH 1 and 2

Question 1

CD3

Answer 1

• molecule expressed on mature T cells
• TCR binds epitope on MHC
• > signaling event occurs after antigen binding
• CD3 activates the t cell to secrete cytokines

Question 2

T cell activation signal 1

Answer 2

• TCR binds to epitope on MHC

- > CD3 activates the T cell

Question 3

T cell activation signal 2

Answer 3

• Costimulation to induce a T cell response
• > CD28 and CD40L
• Triggers transcription of IL-2 and IL-2R and induces proliferation of T cells
• CD40L interacts with CD40 on APC
• > T helper cells can now make and secrete cytokines that help B and Cytotoxic T cells

Question 4

CD 4

Answer 4

• provide help to B cells and cytotoxic T cells (CTLs)

Question 5

Naive lymphocyte

Answer 5

• a mature lymphocyte that has not yet interacted with the antigen it can recognize with its TCR

Question 6

Th 1 secretes

Answer 6

• IL-2
• Interferon-y
• > activates macrophages
• > promotes CMI** (cell mediated immunity)
• > resistance to intracellular pathogens

Question 7

Th 2 secretes

Answer 7

• IL 4-5
• stimulates B proliferation and Ab secretion
• > resistance to extracellular pathogens
• **Humoral Immunity