| cytotoxic | <pharmacology> Chemicals that are directly toxic to cells, preventing their reproduction or growth. Cytotoxic agents can, as a side effect, damage healthy, noncancerous tissues or organs which have a high proportion of actively dividing cells, for example, bone marrow, hair follicles. These side effects limit the amount and frequency of drug administration. (16 Dec 1997) |
|---|---|
| cytotoxic cell | Cells of the immune system that inhibit or help to terminate an immune response, e.g., suppressor macrophages and suppressor T-cells. Synonym: cytotoxic cell. (05 Mar 2000) |
| cytotoxic drugs | <pharmacology> Anti-cancer drugs which act by killing or preventing the division of cells. See: chemotherapy. (13 Nov 1997) |
| cytotoxic reaction | An immunologic (allergic) reaction in which noncytotropic IgG or IgM antibody combines with specific antigen on cell surfaces; the resulting complex initiates the activation of complement which causes cell lysis or other damage, or which, in the absence of complement, may lead to phagocytosis or may enhance T lymphocyte involvement. (05 Mar 2000) |
| cytotoxic T lymphocyte-specific serine protease | <enzyme> Structural sequence given in first source Registry number: EC 3.4.21.- Synonym: cytotoxic t lymphocyte-specific serine protease ccp I, cytotoxic t lymphocyte specific serine protease ccp II, mast cell protease type II (26 Jun 1999) |
| cytotoxic T-cell | <haematology, immunology> Subset of T lymphocytes (mostly CD8) responsible for lysing target cells and for killing virus infected cells (in the context of Class I histocompatibility antigens). (18 Nov 1997) |
| cytotoxic t-lymphocyte | A type of CD8 or, less often, CD4 lymphocyte that kills diseased cells infected by a specific virus or other intracellular microbe. CTLs interact with MHC class I receptors (see Major Histocompatibility Complex). On infected cells and have the prime role in cellmediated immunity (see). Cytovene: See: Ganciclovir. (09 Oct 1997) |
| cytotoxicity | The quality or state of being cytotoxic. Antibody-dependent cell-mediated cytotoxicity (ADCC), a form of lymphocyte-mediated cytotoxicity that functions only if antibodies are bound to the target cell. Lymphocyte-mediated cytotoxicity, the toxic or lytic activity of T-lymphocytes, which may or may not be mediated by antibodies. Cytotoxic T lymphocytes may cause lysis of cells by production of cytolytic proteins such as perforin. B-cells may cause lysis of cells by antibody-complement binding to a target cell. Natural killer cells are cytotoxic without prior sensitization. Toxicity by lymphocytes may also be mediated by antibodies; there are three kinds of cytotoxic T-lymphocytes: those that are antigen-specific as a result of previous allergization (immunization), killer cells, and natural killer cells. See: antibody-dependent cell-mediated cytotoxicity. (05 Mar 2000) |
| cytotoxicity tests, immunologic | The demonstration of the cytotoxic effect on a target cell of a lymphocyte, a mediator released by a sensitised lymphocyte, an antibody, or complement. (12 Dec 1998) |
| cytotoxicity, immunologic | The phenomenon of target cell destruction by immunologically active effector cells. It may be brought about directly by sensitised T-lymphocytes or by lymphoid or myeloid "killer" cells, or it may be mediated by cytotoxic antibody, cytotoxic factor released by lymphoid cells, or complement. (12 Dec 1998) |
| antireticular cytotoxic serum | An antiserum specific for cells of the reticuloendothelial system. (05 Mar 2000) |
|---|---|
| T cytotoxic cells | Lymphocyte-like effector cells which mediate antibody-dependent cell cytotoxicity. They kill antibody-coated target cells which they bind with their fc receptors. (12 Dec 1998) |
| T-lymphocytes, cytotoxic | Immunised T-lymphocytes which can directly destroy appropriate target cells. These cytotoxic lymphocytes may be generated in vitro in mixed lymphocyte cultures (mlc), in vivo during a graft-versus-host (gvh) reaction, or after immunization with an allograft, tumour cell or virally transformed or chemically modified target cell. The lytic phenomenon is sometimes referred to as cell-mediated lympholysis (cml). These cells are distinct from natural killer cells (killer cells, natural) and from killer cells mediating antibody-dependent cell cytotoxicity. (12 Dec 1998) |