• monoclonal antibodies;
  • axon guidance;
  • ectopic neurons;
  • neuronal morphology


We have isolated and characterized four monoclonal antibodies (mAbs B33, E1.9, B30, and B10) that recognize mouse trigeminal sensory neurons at specific times during development. These antibodies permit the study of neuronal differentiation, axon outgrowth, and neuronal maturation in the trigeminal sensory system. With B33, we can follow migrating neural crest and placode cells into the anlagen of the trigeminal ganglion. E1.9 immunoreactivity marks neuronal differentiation and appears in the central nervous system at embryonic day 8.5 (E8.5) and in the peripheral nervous system at E9. E1.9 and B30 show the axonal outgrowth of trigeminal sensory neurons and reveal the pioneering of the peripheral tracts by an early population of ganglionic neurons. At this stage, in the central nervous system, mesencephalic trigeminal neurons are also E1.9 and B30 positive as they migrate to their final location in the rostral metencephalon. B30 and B10 allow us to follow the maturation of these neurons. Also, in about 1% of the embryos, we identified mispositioned or misrouted trigeminal neurons. Furthermore, these biochemical markers facilitate the study of neuronal development in vitro. We find that, based on morphological and biochemical criteria, the maturation of trigeminal neurons in culture is target independent.