Exam 4

Question 1

What causes activation of T-cells?

Answer 1

Dendritic cells present a pathogen to the T-cells, leading to T-cell activation

Question 2

How are helper and cytotoxic T-cell subset limited by MHC classes?

Answer 2

CD4 of helper T-cells are co-receptors for MHC-2
CD8 of cytotoxic T-cells are co-receptors for MHC-1

Question 3

To activate a T-cell, there are two signals required. What are the two signals?

Answer 3

Signal 1: formation of a complex between TCR and MHC-peptide
Signal 2: Co-stimulatory signal from mature DC to T-cell. Can be LFA-1 and ICAM-1, CD28 & B7

Question 4

What happens if signal 1 is given and signal 2 is not?

Answer 4

The cell becomes anergic

Question 5

After signal 1&2 cascade, how is the T-cell activated?

Answer 5

BY a new singular signal, the T-cell becomes active

Question 6

What is SMAC and what happens at the SMAC?

Answer 6

SMAC is the supramolecular activation cluster. It is the immunological synapse, where APCs and T-cells meet to exchange signals

Question 7

What determines proliferation of a T-lymphocyte into a certain subset?