AP BIOLOGY

Detailed explanation-1: -A type of immune cell that can kill certain cells, including foreign cells, cancer cells, and cells infected with a virus. Killer T cells can be separated from other blood cells, grown in the laboratory, and then given to a patient to kill cancer cells.

Detailed explanation-2: -When the perfectly shaped virus antigen on an infected cell fits into the Killer T-cell receptor, the T-cell releases perforin and cytotoxins. Perforin first makes a pore, or hole, in the membrane of the infected cell. Cytotoxins go directly inside the cell through this pore, destroying it and any viruses inside.

Detailed explanation-3: -Killer lymphocytes, the commandos of the immune system, attack tumor cells and cells infected by viruses. They kill by secreting protein molecules that link to form pores in target cells; the cells promptly leak to death.

Detailed explanation-4: -Cytotoxic T lymphocytes, natural killer (NK) cells and antiviral macrophages can recognize and kill virus-infected cells.

Detailed explanation-5: -In cellular immunity, a killer T cell recognizes and kills a virus-infected cell because of the viral antigen on its surface, thus aborting the infection because a virus will not grow within a dead cell.