Final answer:
Cytotoxic CD8+ T cells eliminate target cells by releasing perforin and granzymes, utilizing the Fas/FasL interaction to induce apoptosis, and secret cytokines to recruit other immune elements for cell destruction.
Step-by-step explanation:
Cytotoxic CD8+ T cells are key players in the immune system, responsible for killing cells that have been compromised by infection or have become cancerous. These cells employ three main mechanisms to eradicate target cells. Firstly, they release perforin and granzymes, where perforin punctures the target cell's membrane, allowing granzymes to enter and initiate apoptosis, a programmed cell death. Secondly, cytotoxic T cells can induce apoptosis through the interaction between Fas ligand on their surface and the Fas molecule (FasL) on the target cell, known as the Fas/FasL interaction. Lastly, they can utilize cytokine secretion to promote the death of the target cells. While cytokines themselves do not kill directly, they can recruit other immune agents to assist in the destruction of infected or cancerous cells.
Perforin/Granzyme Release: Cytotoxic T cells release perforin, a protein that creates pores in the target cell's membrane. Granzymes, proteases contained in the cytotoxic T cell's cytoplasmic granules, enter these pores and induce apoptosis, or controlled cell death.
Fas/FasL Interaction: Cytotoxic T cells express Fas ligand (FasL), which binds to the Fas molecule on the target cell's surface. This interaction triggers apoptosis in the target cell.
Cytokine Secretion: Cytotoxic T cells can also secrete cytokines that contribute to killing target cells. These cytokines enhance the killing ability of natural killer (NK) cells and activate other cytotoxic T cells.