What are the different types of T cells?
- Helper T cells (CD4)
- Cytotoxic T cells (CD8)
- Natural killer cells (innate immunity)
- Gamma and Delta T cells
What types of cells will develop from CD4+ T helper cells?
- Th0 (will become Th1 or Th2)
- Treg cells (anti-inflammatory)
- Th17 (pro-inflammatory)
Treg cells will further develop into what?
- Natural
- Adaptive (Th3 cells)
What is the general name for CD4+ and CD8+ T cells
Helper cells and effector cells
When a pathogen (virus or bacteria) penetrates the skin barrier, where does it then go?
- Virus has to enter a cell to work
- Bacteria can stay in the interstitium (extracellular) or it can enter the cell
How does the immune system extract or attack pathogens once they are in the cell?
They can’t. Once they are inside cells we have no way to attack them directly. We have to kill the cell.
What immune cell decides between extracellular or intracellular response to a pathogen?
Niave T cell (T 0) in response to stimulation from macrophage (IL12) or unknown [ninja] cell (IL4)
Th1 and Th2 cells will respond to intracellular or extracellular pathogens?
- Th1 = Intracellular pathogens (cytotoxic)
- Th2 = Extracellular pathogens (chemical/Ig)
Sometimes the wrong signal will be activated
What do Th reg cells do?
They dampen the immune response
What do Th17 cells do?
They are pro-inflammatory and recruit neutrophils to the site of an infection
Can T helper cells become memory cells?
Yes. All of the different types can become memory cells
What do cytotoxic T cells do?
They attack and kills cells with intracellular pathogens
What proteins are expressed on the surface of a thymocyte after it has come out of the bone marrow?
VLA 4, 5, 6
Where does the thymocyte go after it has come out of the bone marrow?
To the thymus
VLA 4, 5 and 6 are expressed on the thyocyte. What does VLA stand for and why is it called that?
VLA = Very Late Antigen. They are proteins that were produced at a later stage.
What do VLA 4 and 5 connect with in the thymus?
They connect with fibronectin
What does VLA 6 connect with in the thymus?
Laminin
What is the purpose of VLA 4, 5 & 6 attaching to Fibronectin and Laminin in the thymus?
It allows the thymocyte to home in on the thalamus and to stay there for further development
