Analysis of glia cell differentiation in the developing chick peripheral nervous system: sensory and sympathetic...

To identify and analyse precursor cells of neuronal and glial cell lineages during the early development of the chick peripheral nervous system, monoclonal antibodies were raised against a population of undifferentiated cells of E6 dorsal root ganglia (DRG). Non-neuronal cells of E6 DRG express surface antigens that are recognized by four monoclonal antibodies, G1, G2, GLI 1 and GLI 2. The proportion of non-neuronal cells in DRG that express the GLI 1 antigen is very high during ganglion formation (80% at E4) and decreases during later development (15% at E14). GLI 2 antigen is expressed only on a minority of the cells at E6 and increases with development. The G1 and G2 antigens are expressed on about 60-80% of the cells between E6 and E14. All cells that express the established glia marker O4 are also positive for the new antigens. In addition, it was demonstrated that GLI 1-positive cells from early DRG, which are devoid of O4 antigen, could be induced in vitro to express the O4 antigen. Thus, the antigen-positive cells are considered as glial cells or glial precursor cells. Surprisingly, the antigen expression by satellite cells of peripheral ganglia is dependent on the type of ganglion: antigens G1, G2 and GLI 1 were not detectable on glial cells of lumbosacral sympathetic ganglia and GLI 2 was expressed only by a small subpopulation. These results demonstrate an early immunological difference between satellite cells of sensory DRG and sympathetic ganglia.(ABSTRACT TRUNCATED AT 250 WORDS)