- Cell-mediated immunity
Cell-mediated immunity is an
immune responsethat does not involve antibodiesor complement but rather involves the activation of macrophages, natural killer cells (NK), antigen-specific cytotoxic T-lymphocytes, and the release of various cytokinesin 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 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
apoptosisin body cells displaying epitopesof foreign antigen on their surface, such as virus-infected cells, cells with intracellular bacteria, and cancer cells displaying tumorantigens;
# 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
phagocytesand microbesthat infect non-phagocytic cells. It is most effective in removing virus-infected cells, but also participates in defending against fungi, protozoans, cancers, and intracellular bacteria. It also plays a major role in transplant rejection.
Wikimedia Foundation. 2010.
Look at other dictionaries:
cell-mediated immunity — /sel mee dee ay tid/, Immunol. immunity independent of antibody but dependent on the recognition of antigen by T cells and their subsequent destruction of cells bearing the antigen or on the secretion by T cells of lymphokines that enhance the… … Useful english dictionary
cell-mediated immunity — cell′ me diated immu′nity n. imu immunity conferred to an individual through the activity of T cells, involving the direct destruction of viruses, foreign particles, etc Compare antibody mediated immunity • Etymology: 1970–75 … From formal English to slang
cell-mediated immunity — /sel mee dee ay tid/, Immunol. immunity independent of antibody but dependent on the recognition of antigen by T cells and their subsequent destruction of cells bearing the antigen or on the secretion by T cells of lymphokines that enhance the… … Universalium
cell-mediated immunity — noun Immunity as a result of a cell mediated immune response … Wiktionary
cell-mediated immunity — (CMI), cellular immunity immunity mediated by T lymphocytes either through release of lymphokines or through exertion of direct cytotoxicity, transmissible by transfer of lymphocytes but not serum; it includes type IV hypersensitivity reactions,… … Medical dictionary
cell-mediated immunity — The type of immunity that results from T cells coming into close contact with foreign cells or infected cells to destroy them; it can be transferred to a nonimmune individual by the transfer of cells … Dictionary of microbiology
cell-mediated immunity — (Medicine) cellular immunity activated by T lymphocytes (rather than antibodies), CMI … English contemporary dictionary
cell mediated immunity — Immune response that involves effector T lymphocytes and not the production of humoral antibody. Responsible for allograft rejection, delayed hypersensitivity and in defence against viral infection and intracellular protozoan parasites … Dictionary of molecular biology
cell-mediated — cell me·di·at·ed sel .mēd ē .āt əd adj relating to or being the part of immunity or the immune response that is mediated primarily by T cells and esp. cytotoxic T cells rather than by antibodies secreted by B cells <cell mediated immunity>… … Medical dictionary
cell-mediated — adjective : relating to or being the part of immunity or the immune response that is mediated primarily by T cells and especially cytotoxic T cells rather than by antibodies secreted by B cells cell mediated immunity cell mediated reactions… … Useful english dictionary