Monoclonal antibodies demonstrate regional specificity in the spinal funiculi of the chick embryo.

To explore the extent and significance of chemical diversity of neurons, monoclonal antibodies were generated that bind to the chick embryonic central nervous system with varying degrees of regional specificity. Mice were immunized against a homogenate of optic nerves from 8-day chick embryos. Antibody was screened by an indirect fluorescence immunohistochemical method using frozen sections of embryonic neural tissues. From 3 fusion experiments, 58 lines of hybrydoma were cloned. Twenty-three monoclonal antibodies were studied in detail, and here reported, for their characteristic staining patterns in the spinal cord of 6-day embryos. The majority of the antibodies bound preferentially to different subregions of spinal funiculi, in which glial elements are still undeveloped. At least 6 subregions could be distinguished in the funiculi, probably corresponding to the developing spinal tracts. For 8 of the antibodies, immunoreactive polypeptides were identified in an electrophoretic analysis.