Lecture 9 - Activation and differentiation of CD4 + T-cells (1) Flashcards
What is the role of the resident dendritic cells in the lymph node paracortex?
Capture and presenting antigens that are draining into the lymph nodes
What is needed in addition to antigens in order to activate a T-cell?
A co-stimulatory molecule
What happens when a T-cell recognises an antigen but is not co-stimulated?
It becomes anergic (unresponsive to the antigen)
How is T-cell activation inhibited?
By using an inhibitory co-stimulatory molecule
What is the role of CTLA-4?
It inhibits T-cell activation against self antigens
[…] events are important in supporting T-cell activation.
Cell adhesion
What is an example of important adhesion molecules for T-cell/DC interaction?
ICAM-1 and LFA-1 interactions
What happens when the T-cell receptor and MHCII interact?
- LFA-1 and ICAM-1 bind with higher affinity
- So more T-cell receptor/MHCII interactions can occur
What happens if the T-cell does not recognise the antigen?
- The LFA-1/ICAM-1 interaction is not strengthened
- T-cell moves to look for an antigen it can recognise
What is the point where CD4+ T cells and DCs make contact called?
The immunological synpase
What are the clusters of molecules that form at the T-cell/DC interface called?
Supramolecular activation clusters (SMACs)
The formation of the [A] facilitates important signals that promote [B] activation.
A - immunological synpase
B - T-cell
How does antigen binding and co-stimulation cause T-cell activation?
They activate intracellular signals to alter gene transciption
What happens when CD4+ T-cells are activated?
- T-cells are stimulated to proliferate (clonal expansion)
What happens during clonal expansion of CD4+ T-cells?
- The T-cells express IL-2 on their membranes
- And secreted IL-2
- IL-2 acts to drive T-cell proliferation
