− | Lastly, the final line of defense for the innate response to viruses lies in the actions of [[Natural Killer cells|'''Natural Killer (NK) cells''']]. These warriors monitor the production of [[Major Histocompatability Complexes|MHC]] (Major Histocompatibility Complex) on the surface of cells, which is produced as part of the adaptive response. A cell whose cellular machinery is compromised by viral infection will experience a drop in the amount of MHC it produces. When a cell's MHC production drops, NK cells trigger '''apoptosis''', otherwise known as ''programmed cell death'', in these cells. In inducing apoptosis this stops the use of the machinery of the infected cells that is being hijacked by the viruses for their replication. Once a cell has undergone apoptosis, it's cleared by macrophages through the process of [[Phagocytosis|phagocytosis]], killing the virus inside. As such, this is a non-specific targeting based simply on the ability of a cell to function normally, which also lends them to playing a role in targeting malignant cells. NK cells are incapable of directly targeting viral infection. | + | Lastly, the final line of defense for the innate response to viruses lies in the actions of [[Natural Killer cells|'''Natural Killer (NK) cells''']]. These warriors monitor the production of [[Major Histocompatability Complexes|MHC]] (Major Histocompatibility Complex) on the surface of cells, which is produced as part of the adaptive response. A cell whose cellular machinery is compromised by viral infection will experience a drop in the amount of MHC it produces. When a cell's MHC production drops, NK cells trigger '''apoptosis''', otherwise known as ''programmed cell death'', in these cells. Inducing apoptosis stops the use of replication machinery of the infected cells being hijacked by the viruses for their replication. Once a cell has undergone apoptosis, it's cleared by macrophages through the process of [[Phagocytosis|phagocytosis]], killing the virus inside. As such, this is a non-specific targeting based simply on the ability of a cell to function normally, which also lends them to playing a role in targeting malignant cells. NK cells are incapable of directly targeting viral infection. |