cytokine

noun

Etymology: From cyto- + -kine from Ancient Greek κίνησις (kínēsis, “movement”).

1. Any of various small regulatory proteins that regulate the cells of the immune system.

   “Thus, in the case of viral infection, mechanisms of resistance would be threefold, namely, interferon production, the immune response, including both antibody and lymphokine production, and the generation of lymphokine-like substances by the infected cells themselves. These latter substances have been defined as cytokines.”

   “A fundamental feature expressed by the vast majority of cytokines is a profound immunomodulatory activity. Many cytokines, presently available in pure recombinant form, modify bone cell metabolism.”