Immunology-T Cell Activation and Function

Question 1

What signals are necessary to activate T cells?

Answer 1

Signal 1: TCR with antigen

Signal 2: CD28 of T cell with CD80 of APC

Question 2

Perforin and Granzymes

Answer 2

molecules within granules of CTL that are released upon direct cell contact and stimulation

Perforin: similar to C9, forms pores in target cell membrane

Granzymes: enter target cell through perforin pores, cause apoptosis

Question 3

What happens to Th0 cells are presented with antigen from macrophages?

Answer 3

Th0>Th1

release of IL-12

if related to gut, secrete IL-25, activating Th0 to produce IL-13 and change to Th2

Question 4

What do Th1 cells secrete?

Answer 4

IL-2: proliferation of all T cell populations

Gamma interferon: activate tissue macrophages, principal effector mech in defense against intracellular bacteria

Question 5

What do Th2 cells secrete?

Answer 5

IL-4: stimulates B cell growth and heavy chain switch, proliferation of basophils/mast cells

IL-5: proliferation and differentiation of eosinophils

Question 6

What do both Th1 and Th2 secrete?

Answer 6

IL-3 and GM-CSF

activate and induce proliferation of neutrophils and macrophages

Question 7

What do regulatory T cells secrete?

Answer 7

IL-10 and TGF-beta

down-regulate immune responses to inhibit the immune response after elimination of original infection