T-cell Effector Functions

Question 1

T-cell migration

Answer 1

T-cell activation occurs in the secondary lymph organs but the infection is often occurs in the periphery

To guide the T-cell to the infection side, a guidance system of cytokines and chemokines is in place

Cytokines = upregulate adhesion molecule expression on the endothelium

Chemokines = attracts cells to the site

Question 2

CD8 T-cells

Answer 2

CD8 T-cells are cytotoxic

Their killing is very specific so they must have cell-cell contact

Adjacent cells are unaffected by the killing of the target cell

Question 3

Granzyme/perforin killing

Answer 3

Granules are released onto the target via the immunological synapse

Perforin creates pores in the target cell, this then allows granzyme entry

Granzyme activates the caspase cascade

Question 4

Contraction

Answer 4

As the antigen is cleared, the stimulus for co-stimulation subsides and T-cell responses decline

Homeostasis is restored

Question 5

Memory

Answer 5

Some progeny develop into long-lived quiescent cells

Memory cells are responsible for the accelerated and enhanced secondary immune response