Cell-mediated immunity
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220280608
2008-06-19T02:43:56Z
JForget
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Reverted edits by [[Special:Contributions/124.254.82.109|124.254.82.109]] ([[User talk:124.254.82.109|talk]]) to last version by 170.223.207.25
'''Cell-mediated immunity''' is an [[immune response]] that does not involve [[antibodies]] or [[complement system|complement]] but rather involves the activation of [[macrophage]]s, [[natural killer cell]]s (NK), [[antigen]]-specific [[cytotoxic]] [[T-lymphocytes]], and the release of various [[cytokines]] in response to an antigen. Historically, the immune system was separated into two branches: [[humoral immunity]], for which the protective function of immunization could be found in the humor (cell-free bodily fluid or [[blood plasma|serum]]) and '''cellular immunity''', for which the protective function of immunization was associated with cells.
Cellular immunity protects the body by:
# activating antigen-specific cytotoxic T-lymphocytes that are able to induce [[apoptosis]] in body cells displaying [[epitopes]] of foreign antigen on their surface, such as [[virus]]-infected cells, cells with intracellular [[bacterium|bacteria]], and cancer cells displaying [[tumor]] antigens;
# activating macrophages and natural killer cells, enabling them to destroy intracellular pathogens; and
# stimulating cells to secrete a variety of cytokines that influence the function of other cells involved in adaptive immune responses and innate immune responses.
Cell-mediated immunity is directed primarily at microbes that survive in [[phagocytes]] and [[microbes]] that infect non-phagocytic cells. It is most effective in removing virus-infected cells, but also participates in defending against [[fungi]], [[protozoan]]s, [[cancer]]s, and intracellular bacteria. It also plays a major role in [[transplant rejection]].
{{Blood}}
{{Immune_system}}
[[Category:Immune system]]
{{immunology-stub}}
[[ar:مناعة خلوية]]
[[es:Inmunidad celular]]
[[id:Kekebalan selular]]
[[it:Immunità cellulare]]
[[pl:Odpowiedź odpornościowa komórkowa]]
[[pt:Imunidade mediada por célula]]
[[sv:Cell-medierad immunitet]]