| killer cell | 1. <immunology> Mammalian cells which can lyse antibody coated target cells. They have a receptor for the Fc portion of IgG and are probably of the mononuclear phagocyte lineage, though some may be lymphocytes. Not to be confused with cytotoxic T-cells which recognise targets by other means and are clearly a sub set of T lymphocytes. This confusion exists in the early literature. 2. Natural killer cell are CD3 negative large granular lymphocytes, mediating cytolytic reactions that do not require expression of Class I or II major histocompatibility antigens on the target cell. 3. Lymphokine activated killer cells are NK cells activated by interleukin-2 (LAK cells). (13 Nov 1997) |
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| killer 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) |
| killer cells, lymphokine-activated | Cytolytic lymphocytes with the unique capacity of killing natural killer (nk)-resistant fresh tumour cells. They are interleukin-2-activated nk cells that have no MHC (major histocompatibility complex) restriction or need for antigen stimulation. Lak cells are used for adoptive immunotherapy in cancer patients. (12 Dec 1998) |
| killer cells, natural | Cells responsible for spontaneous cytotoxicity of a variety of tumour cells without prior immunization. These natural killer cells are found in non-immune humans and experimental animals and are thought by some to be the same as killer cells (killing by antibody-dependent cell cytotoxicity), but they can also kill in the absence of antibody. (12 Dec 1998) |
| killer plasmid | <molecular biology> These plasmids are found in some strains of Kluyveromyces marxianus where the cells contain multiple cytoplasmic copies of dsDNA plasmids. Such cells secrete a glycoprotein toxin. The plasmids and the killer function can be transferred to yeast. (18 Nov 1997) |
| killer T-cell | 1. <immunology> Mammalian cells which can lyse antibody coated target cells. They have a receptor for the Fc portion of IgG and are probably of the mononuclear phagocyte lineage, though some may be lymphocytes. Not to be confused with cytotoxic T-cells which recognise targets by other means and are clearly a sub set of T lymphocytes. This confusion exists in the early literature. 2. Natural killer cell are CD3 negative large granular lymphocytes, mediating cytolytic reactions that do not require expression of Class I or II major histocompatibility antigens on the target cell. 3. Lymphokine activated killer cells are NK cells activated by interleukin-2 (LAK cells). (13 Nov 1997) |
| killer yeast | <microbiology> A yeast that secretes a toxin that can kill other yeasts. (09 Oct 1997) |
| lady-killer | A gallant who captivates the hearts of women. "A renowned dandy and lady-killer." Source: Websters Dictionary (01 Mar 1998) |