Thanks for the several answers and references to follow up. Its
clear that T-cells (and other similar immune system cells) have to
work with three "senses":
1) Systemic "fire bell": immuno-response from organs has to be
systemic simply because the path from organs to infection is circulation:
no immuno-activating signal can flow against the circulation so the
only mechanism avaliable is to signal all-hands-on-deck and rely on
some immuno-cells encountering the infection as they circulate.
2) Local activation: chemical triggers from infection area; (directional
concentration gradient?)
3) Touch everything. (Everything? or do they work on a track across a
cell membrane or otherwise be guided).
Time to read some more; thanks for tolerating the bio-illiterate...
--
John.
John J. Barton jjb at watson.ibm.com (914)784-6645
H1-C13 IBM Watson Research Center P.O. Box 704 Hawthorne NY 10598
