Question

Which of the following statements is false regarding CD8 T cells?

1) CD8 T cells have only one effector function, which is cytotoxicity.
2) Compared with naive CD4 T cells, naive CD8 T cells have more stringent requirements for co-stimulatory activity.
3) Effector CD8 cells require co-stimulation to kill their target cells.
4) The most potent antigen-presenting cell for naive CD8 T cells is the dendritic cell.

Answer 1

The false statement regarding CD8 T cells is that they have only one effector function, which is cytotoxicity, as they can also emit cytokines. Effector CD8 T cells do not require co-stimulation to kill their target cells.

Step-by-step explanation:

The false statement regarding CD8 T cells is: CD8 T cells have only one effector function, which is cytotoxicity. In fact, CD8 T cells not only have the effector function of cytotoxicity but can also secrete various cytokines. This effectively debunks the first statement. Regarding naive CD8 T cells, they indeed have more stringent requirements for co-stimulatory activity compared to naive CD4 T cells, making the second statement true. The third statement that effector CD8 cells require co-stimulation to kill their target cells is also false; once they are effector cells, they do not require additional co-stimulation to carry out cell lysis. The fourth statement is true because dendritic cells are the most potent APCs for naive CD8 T cells as they can present antigens via MHC I molecules which are necessary for CD8 T cell activation.