cell-mediated immunity

Also found in: Dictionary, Thesaurus, Legal, Acronyms, Encyclopedia, Wikipedia.

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

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

cell-mediated 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).
Enlarge picture

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.


effected by cellular rather than chemical elements.

cell-mediated hypersensitivity
see delayed hypersensitivity.
cell-mediated immunity
see cellular immunity.
cell-mediated lympholysis assay
a test of cell-mediated immunity in which activated cytoxic T lymphocytes cause lysis of 51Cr-labeled target cells.
References in periodicals archive ?
Cross-reactive, cell-mediated immunity and protection of chickens from lethal H5N1 influenza virus infection in Hong Kong poultry markets.
Our finding that patients with NPC have a low degree of cell-mediated immunity confirms a finding by Hsu et al, who published the results of their study of 344 patients with NPC in 1980.
If there is an adverse indirect effect on cell-mediated immunity due to PRN exposure, it could result from altered antigen processing and presentation characteristics of the APC.
The need to stimulate cell-mediated immunity has become more acute with the advent of modern, recombinant vaccines, says Beltz.
In cell-mediated immunity, white blood cells processed by the thymus are involved and attack the antigen directly.
Although the immune system changes are not well understood, a shift from cell-mediated immunity toward humoral immunity is believed to occur.
002% of the genome coding sequence to recognize, researchers in a range of medical specialties explore how pathogen molecules are converted to molecules that are targets for cell-mediated immunity, the binding of processed peptides to major histocompatibility complex (MHC) molecules, and the role of the pathogen itself in modifying the immune response by interfering with antigen processing and the downstream immune responses.
Older adults, a fast-growing population in the United States, are the population most susceptible to the disease, which is believed to be associated with an age-related decline in cell-mediated immunity to latent varicella-zoster virus (N.
Most, if not all, are vaccines that induce cell-mediated immunity (CMI), but for more than 20 years, I have argued that a vaccine candidate must approach or realize complete blockade of HIV inflection at the site of cell entry.
Documentation has already been established that cell-mediated immunity is depressed in patients with nasopharyngeal carcinoma.
Listeria monocytogenes as a short-lived delivery system for the induction of type 1 cell-mediated immunity against the p36/LACK antigen of Leishmania major.

Full browser ?