Immunology - Content. ELISpot Assay explained with a flash animation. BEN. Virtual Immunology Lab. BIOL 230 Lecture Guide - Cell Mediated Immunity: A Cytotoxic T-Lymphocyte Inducing Apoptosis of a Virus-Infected Cell. A Cytotoxic T-lymphocytes (CTL) using Perforins and Granzymes to Induce Apoptosis of a Virus-Infected Cell Binding of the CTL to the infected cell triggers the CTL to release pore-forming proteins called perforins and proteolytic enzymes called granzymes.