Perforin -
Cytotoxic T Lymphocyte-Mediated Apoptosis

Cytotoxic T lymphocytes (CTLs) recognize foreign antigens presented on the surface of infected host cells,
Upon activation, CTLs secrete perforin, a transmembrane pore-forming molecule, which promotes entry of the CTL granule serine proteases called granzymes.
Granzymes cleave proteins at aspartate residues and thus activate a variety of cellular caspases. In this way, the CTL kills target cells by directly inducing the effector phase of apoptosis.
Cytotoxic T cell
NK cell
Plasma cell
Monocyte