Because viruses lurk inside host (e.g. human) cells where antibodies cannot reach them, the only way they can be eliminated is by killing the infected host cell. To do this, the immune system uses a k [..]

a group of T cells that is activated by helper T cells and have the ability to destroy cells infected by foreign invaders (such as viruses). Also known as cytotoxic T cells.

also called cytotoxic T cells; differentiated (trained) T cells that recognize specific antigens on the surface of a target cell, e.g, a body cell infected with virus; the killer T cell binds to the target cell and kills its; also defends against cancer cells