<prompt> Perforin -Cytotoxic T cellNK cellPlasma cellMonocyte  <response>: Cytotoxic T Lymphocyte-Mediated ApoptosisCytotoxic 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. 