Learning Objective:

Understand how cytotoxic T cells recognize targets and induce apoptosis in virus-infected, neoplastic, and transplanted cells.

Cytotoxic T cell

Function

• Kill virus-infected cells, tumor cells, and donor graft cells by triggering apoptosis.

Mechanism:

• Release cytotoxic granules containing
  • Perforin → forms pores in the target cell membrane
  • Granzyme B → activates caspases → apoptosis

Recognition:

• Express CD8, which binds to MHC I on all nucleated cells.
• MHC I presents intracellular antigens (e.g., viral peptides).

Activity

Activity