anti-antitoxin

an·ti-an·ti·tox·in

(ăn′tē-ăn′tē-tŏk′sĭn, ăn′tī-)
n.
An antiantibody that is directed against an antitoxin and counteracts its effects.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.