CTLs do not simply lyse target cells. The mechanism is more the activation of apoptotic pathways in target cells.
Virally infected cells presenting viral peptide on MHC I encounter antigen specific CTL, initiating CTL expression of weaponry.

Perforin - forms pore in cell membrane
Granzyme - enters cell via perforin pore; granzyme is a protease that targets signaling proteins - initiating apoptosis
CD95L (ligand) - binds CD95 on target cell, initiating apoptosis - activates enzymatic portion on target cell - this activates apoptotic enzymes.

Note: apoptosis does not result in release of cell contents, the cell segregates and compartmentalises itself into apoptotic bodies which are phagocytosed.

	Created by Austin Davies over 10 years ago

Lecture 23 - immunology