cell-mediated immunity

(redirected from T-cell response)
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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 ?
To minimize the impact of anti-TB treatment on T-cell responses, only those patients with less than three weeks of anti-TB chemotherapy were included.
For example, on the basis of exome sequencing data of chronic lymphocytic leukemia, epitope prediction algorithm NetMHCpan has been used to identify the HLAbinding peptides that are derived from leukemia-specific mutations, followed by experimental validation of their binding to HLA-I and quantification of the potential of eliciting a [CD8.sup.+] T-cell response [88].
Developmental activation of the AhR diminished the virus-specific [CD4.sup.+] T-cell response to infection.
OSP is encephalitogenic in mice [52] and elevated T-cell responses to OSP have been reported in a small proportion of patients with MS in two studies [53, 54].
However, with purified proteins or peptides, in most cases adjuvants or suitable danger signals are necessary in order to prime T-cell responses. In the last decade, dendritic cells (DCs), powerful antigen presenting cells, have surfaced as the most important cells, to target antigens for uptake, processing, and presentation to T cells [1].
Vaccine regimens involved heterologous prime-boost combinations, as this has been shown to result in better T-cell responses to HIV compared with homologous prime-boost strategies.
"In most solid tumors, those antibodies are not going to be enough; they probably won't hurt, but they're not sufficient, and you need the T-cell response to get real tumor-cell killing," said Dr.
In the proof-of-concept trial, 133 patients infected with hepatitis C virus (HCV) genotype 1 were randomized to either triple therapy comprising the experimental GI-5005 vaccine, which is designed to elicit a T-cell response specific to HCV, along with pegylated interferon alfa-2b plus ribavirin (P/R), or the standard P/R therapy alone.
"Years of animal studies on vaccines and other immunotherapies have demonstrated that it's the T-cell response that mediates tumor destruction.
"This clinical efficacy is probably related to a vaccine-induced HPV-16 T-cell response," said Dr.
No correlation was observed between baseline viral load and HIV-specific CD4+ and CD8+ T-cell responses. Subjects who started HAART at the time of acute infection had no better HIV-specific T-cell responses than those who started therapy after seroconversion, and the absence of any treatment or the incomplete virological control did not prevent the development of an HIV-specific CD4+ T-cell response.
"Avoiding sources of false positive T-cell response, eliminating toxic contaminants that inhibit T-cell activation, and developing and validating reproducible production processes have been the key drivers in the development of this new product line."