phytomitogen

[fī′tō-mītə-jən, -jĕn′]
n.
  1. A mitogenetic lectin causing lymphocyte transformation accompanied by mitotic proliferation of the resulting blast cells identical to that produced by antigenic stimulation.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.