neutrotaxis

[nōō′trə-tăksĭs]
n.
  1. A response designated as attractive, repulsive, or neutral, shown by neutrophilic white blood cells when stimulated by a substance.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.