cell-mediated immunity


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cell-·me·di·at·ed im·mu·ni·ty (CMI),

, cellular immunity
Immune responses mediated by activated, antigen-specific T lymphocytes. These T cells may function as effector cells or may orchestrate propagation of the inflammatory response and cellular recruitment through their secretion of cytokines and chemokines.
Synonym(s): delayed hypersensitivity (1)

cell-mediated immunity

n.
Immunity resulting from a cell-mediated immune response. Also called cellular immunity.

cell-me·di·at·ed im·mu·ni·ty

, cellular immunity (CMI) (sel'mē'dē-āt-ĕd i-myū'ni-tē, sel'yū-lăr)
Immune responses that are initiated by T lymphocytes and mediated by T lymphocytes, macrophages, or both (e.g., graft rejection, delayed-type hypersensitivity).
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CELL-MEDIATED IMMUNITY

cell-mediated immunity

Abbreviation: CMI.
The regulatory and cytotoxic activities of T cells during the specific immune response. This process requires about 36 hr to reach its full effect. Synonym: T-cell–mediated immunity See: illustration; humoral immunity

Unlike B cells, T cells cannot recognize foreign antigens on their own. Foreign antigens are recognized by antigen-presenting cells (APCs) such as macrophages, which engulf them and display part of the antigens on the APC's surface next to a histocompatibility or “self-” antigen (macrophage processing). The presence of these two markers, plus the cytokine interleukin-1 (IL-1) secreted by the APCs activates CD4 helper T cells (TH cells), which regulate the activities of other cells involved in the immune response.

CMI includes direct lysis of target cells by cytotoxic T cells, creation of memory cells that trigger a rapid response when a foreign antigen is encountered for the second time, and delayed hypersensitivity to tissue and organ transplants. T cells also stimulate the activity of macrophages, B cells, and natural killer cells. These functions are controlled largely by the secretion of lymphokines such as the interleukins, interferons, and colony-stimulating factors. Lymphokines facilitate communication and proliferation of the cells in the immune system.

See also: immunity

cell-mediated immunity

Action by the immune system involving T cells (T LYMPHOCYTES) and concerned with protection against viruses, fungi, TUBERCULOSIS and cancers and rejection of foreign grafted material. Cell-mediated immunity is not primarily effected by ANTIBODIES.
References in periodicals archive ?
Efficacy assessment of a cell-mediated immunity HIV-1 vaccine (the Step study): a double-blind, randomised, placebo-controlled, test-of-concept trial.
Our study demonstrated that 0.5% green tea by-product inclusion in the finishing diet had positive effects on the cell-mediated immunity of pigs.
Rejection of a transplanted organ is a function of cell-mediated immunity, so it is not surprising that drugs that suppress transplant rejection also inhibit vulvovaginal cell-mediated immunity.
The effect of mushrooms on increased NK cell activity is related to higher production of interferon-gamma, a critical cytokine involved in both innate and cell-mediated immunity. Dietary Supplementation with White Button Mushroom Enhances Natural Killer Cell Activity in C57BL/6 Mice, was published in the Journal of Nutrition (2007) Vol.
Protective immunity against Newcastle disease: the role of cell-mediated immunity. Avian Dis.
A total of 79% of the adolescents who received the booster showed persistent cell-mediated immunity to any of the three pertussis antigens.
We conducted a prospective study of 60 patients in a tertiary care referral center to ascertain the status of cell-mediated immunity as determined by delayed hypersensitivity reactions in patients with nasopharyngeal carcinoma (NPC) or allergic rhinitis.
A sampling of topics includes ABC transporter, cell-mediated immunity, Herceptin, Frederick Sanger, and von Willebrand disease.
One project at NADC appears to have uncovered an immunological "trapdoor" that may help scientists overcome maternal immunity through vaccines that trigger cell-mediated immunity. The study involved developing a T-cell response to introduction of bovine viral diarrhea virus to calves.
It is unclear, however, whether PRN also adversely affects cytotoxic T lymphocytes (CTLs), the primary (1[degrees]) effectors of cell-mediated immunity. In this study we examined both the direct and indirect effects of PRN exposure on CTL activation and effector cell function to gauge its likely impact on cell-mediated immunity.
When a primary immune deficiency is suspected in a patient, it's often helpful to consider the patient's history and symptoms in terms of the four components of specific host resistance: antibody, complement, phagocytic cells, and cell-mediated immunity.

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