| mediator | An object or substance by which something is mediated, such as 1. <anatomy> A structure of the nervous system that transmits impulses eliciting a specific response. 2. <chemistry> A chemical substance (transmitter substance) that induces activity in an excitable tissue, such as nerve or muscle, or 3. <cell biology> A substance released from cells as the result of the interaction of antigen with antibody or by the action of antigen with a sensitised lymphocyte. (18 Nov 1997) |
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