Chapter 9: Antigen-Presenting Cells and T Cell Activation T cells that express the CD4 marker will typically function in the immune system as: T cells that express the CD8 marker will typically function in the immune system as: Label the following diagram that illustrates the molecular interactions of T cells with antigen- presenting cells: APC Virus infected cell 333 T cell (helper) 55 T cell (cytotoxic) Mature, naïve T cells require three signals for activation. a) What is signal #1? b) What is signal #2? c) What is signal #3?
d) What type of cell can provide both signal #1 and signal #2? Give an example. e) What happens if the T cell receives signal #1, but does not receive signal #2? f) What type of cell is the best activator of T cells? Why is this so? Hint: Table 9.1 on the Canvas course site. g) What does CD4 or CD8 do? h) What does CD3 do? Look at the table in the Chapter 1 review exercises. Can you add to them to make them more complete?