Lymphocyte Activation

Question 1

What state do lymphocytes need to be in to carry out their function?

Answer 1

Activated - they recieve a signal

Question 2

An activated lymphocyte is in an active state of p…………. (division) or d……………… (develop specialised features) ie. It is changed

Answer 2

Proliferation

Differentiation

Question 3

Eukaryotic cell cycle

Answer 3

Enter cell cycle sequence (remain in G1 for ~48hours)

Enter S phase (DNA synthesis)

Divide

POPULATIONS OF EFFECTOR LYMPHOCYTES

Eg. B cells to memory or plasma cells
Eg. T cells to Tc, Th, Tm and cytocrine secretors

Question 4

After mitogenic or antigenic stimulation, what changes does lymphocyte activation result in?

Answer 4

Increase in size
More extensive cytoplasm
Nucleoli visible, nucleus less dense stain
After ~72hrs resemble lymphoblasts (actively synthesizing DNA; fine chromatin & basophilic nucleoli)

Question 5

What changes can be seen in an activated B cell?

Answer 5

More cytoplasm
Nucleoli visible
Extensive rough ER because synthesising antibody

Question 6

What 2 signals do lymphocyte receptors require to become activated?

Answer 6

1 - bing ag via ag receptor on lymphocyte
2 - co-stimulatory molecules on lymphocyte surface & antigen presenting cells required for cell-cell interaction & signal transduction events (cytoplasm to nucleus)