Final answer:
Upon antigen activation, CD8 cytotoxic T cells release perforins which are proteins that create pores in the target cell membranes, allowing granzymes to enter and induce apoptosis.
Step-by-step explanation:
Upon antigen activation, CD8 cytotoxic T cells release perforins, which are proteins that punch holes in the membrane of target cells, leading to cell death. After recognizing infected cells through the interaction between their T-cell receptors (TCR) and antigen-presented with MHC I on the surface of the target cell, these cytotoxic T cells release perforin along with granzymes. Granzymes, which are proteases, enter through the perforin-created pores and induce apoptosis in the target cell. This process is part of the body's immune response to pathogens and provides a controlled means of eliminating infected cells without releasing the pathogens to infect nearby cells.