The answer is granzymes. are serine proteases which trigger the apoptotic cascade in target cells. Apoptotic enzymes activated by granzymes can also destroy viruses or other cytoplasmic pathogens in the target cells so that the pathogens cannot infect nearby cells. Dead target cells are rapidly ingested by macrophages. The Tc cells also produce perforin pores to allow granzymes to enter the target cell.
