from The American Heritage® Dictionary of the English Language, 4th Edition
- n. That which the immune system identifies as foreign to the body.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Any entity other than oneself.
- n. All agents and substances that are not body's own.
from the GNU version of the Collaborative International Dictionary of English
- n. That which is not oneself.
- n. Any material that enters the body and is not recognized by the immune system as being part of its body, thereby triggering an immune response; any material appearing to the immune system to be foreign to its body.
Sorry, no etymologies found.
It seems to me there is one: the word nonself-referring.
If they did not exactly scream "nonself," these antigens at least whispered "not quite self," and did so loudly enough to attract notice from the immune system.
The dividing line between self and nonself is taken to be the skin.
Crozier floats in this warm, buoyant sea of nonself and listens to dreams that are not his own.
In effect, it fails to distinguish between self and nonself.
In light of this and subsequent discoveries, Alan Houghton, a cancer immunologist at Sloan-Kettering, has come to refer to cancer cells as "altered self," rather than "nonself."
But cancer cells teeter on the edge between self and nonself.
IKE all tumor immunologists, Boon was working at a boundary as much philosophical as scientific: Where does self end and nonself begin?
Beginning in the earliest weeks of life our T cells are programmed in the thymus to recognize only nonself proteins; T cells that recognize self proteins are ablated, or destroyed, lest they attack our own tissues.
Each cell in effect cannibalizes every type of protein made inside it and allows the immune system to sample bits of the protein to make sure it is self and not nonself.